ALBERT

Notes: New synthetic techniques are now available for the preparation of “model” polymer networks of known and carefully controlled molecular structure. The preparation of such networks and their utilization in elucidating molecular aspects of rubberlike elasticity are illustrated using highly elastomeric, unfilled networks of polydimethylsiloxane. In one such preparative technique, hydroxyl-terminated chains are end-linked using either a tetrafunctional or trifunctional silicate, in either the undiluted state or in solution. Because of the selectivity and completeness of the reaction, the molecular weight and molecular weight distribution of the network chains are to good approximation those of the chains prior to their end-linking into the network structure. The experimentally determined stress-strain isotherms and degrees of equilibrium swelling of the resulting networks are then used to evaluate the molecular theories of rubberlike elasticity, particularly with regard to the dependence of the elastic modulus and ultimate properties on the degree of cross linking and the cross-link functionality. Another preparative technique employs random and block copolymers containing reactive vinyl groups in known amount and known distribution along the chains. Selectively cross-linking through these sites then yields model networks ranging from random to highly non-random in chain length distribution. These networks are particularly useful for characterizing the effects of very short chains on the average degree of cross-linking or average network chain length as obtained from stress-strain and swelling equilibrium measurements.

Notes: Some examples of interaction between various soluble and crosslinked synthetic polymers and physiological environment and its constituents are exemplified and discussed. Our view is confronted with several typical published data and is also illustrated by few original results.

Notes: Advances in the major areas of the cationic ring-opening polymerizations are discussed. In the first part synthesis of new polymers is reviewed; this includes mainly novel block and graft copolymers based on the di- and multicationically ended living polyacetals and polyethers (polyTHF).Recent data on thermodynamics of nonideal systems, giving dependence of [M]e on [M]o, are summarized with special emphasize of the differences between monomers due to variation of their nucleophilicities.Discussion of kinetics and mechanisms of polymerization of cyclic acetals and ethers is focused on the macroring formation and reactivities of active centers.The reactivity of covalent and various ionic growing species are compared in the polymerization of cyclic ethers (THF and oxepane) and oxazolines. Reasons for much lower reactivity of covalent than ionic species and reasons for similar reactivities of macroion-pairs and macroions are presented.It is shown, that the kinetically controlled proportions of macrorings in the polymerization of these and other heterocyclic monomers depend on the structure of the end-groups, formed upon initiation. Initiation with acids, giving H-X∼ (where X=heteroatom) end-groups, leads to the kinetically enhanced proportion of macrorings. This is particularly important for the low degrees of polymerization.

Notes: The immobilization of various enzymes, mainly of hydrolases, by carriers with e.g. maleimide, benzoquinone, N-substituted sulfamic acid, and diazonium groups will be described. As basic polymer mainly poly(vinyl alcohol) was used which was derivatized. The immobilization of enzymes was performed also with synthetic wood pulp. The influence of unfolding of the enzyme chains during the immobilization reaction on the characteristics of the immobilization products as well as the influence of the spacer length on the immobilization was investigated. An example of a soluble immobilized trypsin product is given. Some aspects of the characterization of immobilized enzymes will be discussed. Also some examples of whole cell immobilization as well as of application of immobilized enzymes and immobilized whole cells will be described.

Notes: The monomer-monomer interaction plays important roles in many cases of alternating copolymerizations. This article describes first a review of alternating copolymerizations in terms of the varieties of the types of reactions, the types of monomers, and the combinations of monomers. The reactions of alternating copolymerizations are classified into the following five types; (i) free radical alternating copolymerization involving polar vinyl monomers (Type-1), (ii) free radical alternating copolymerization between olefins and acrylic monomers with the assistance of Lewis acids (Type-2), (iii) alternating copolymerization of olefins and diolefins with Ziegler-Natta catalysts (Type-3), (iv) ring-opening copolymerization of heterocyclic monomers (Type-4), and (v) spontaneous alternating copolymerization via zwitterion intermediates (Type-5). The monomers which have been involved in alternating copolymerizations are polar vinyl compounds, mono-olefins, diolefins, heterocyclic compounds, SO2, CO2 and isocyanates. Then, the general patterns of the mechanisms of sequence control were described, and the detailed mechanisms were discussed in the copolymerizations of Types-1, -2 and -5 in which the monomer-monomer interaction has been reported to be responsible for the initiation and the sequence regulation.

Notes: Many properties of semi dilute and concentrated polymer solutions can be understood simply in terms of certain scaling laws (1). In the first part of this talk, we present scaling results for various problems connected with colloid science. (1) Near a solid wall (or an interface) when the chains are not adsorbed at the interface, a polymer solution is expected to show a depletion layer of sizeable thickness near the wall (2). (2) The existence of these layers may induce an attraction between colloïdal grains suspended in the solution. This attraction can lead to flocculation when the grain radius b is larger than the correlation length ζ(c) of the solution; in the opposite limit (b 〈 ζ) the attraction is weak (3). (3) We discuss the entropy of polymer chains confined in very narrow tubes of diameter D. For a single chain in a good solvent this problem has been understood sometime ago (4), but for chains in a melt the situation is surprisingly different (5). (4) Freely suspended liquid films occurring for instance in foams should be often stabilised by the addition of long polymer chains (always assuming no adsorption on the limiting surfaces) : the chains lose entropy by confinement, and the result is a stabilisation free energy (per cm2 of film) varying like the inverse film thickness (6).In the second part of the talk, we discuss some aspects of the motions and flows of entangled systems. (1) The cooperative diffusion of the polymer through the solvent (or vice versa) does not involve disentanglements and is amenable to simple scaling laws (7) which have to some extent be confirmed by photon beat experiments (8). It must be emphasized, however, that these laws are valid asymptotically for long chains, in very good solvents, and in a semi dilute regime where the chains do overlap, but where the concentration is still low enough, so that the friction processes are still dominated by the solvent viscosity (as opposed to monomer-monomer friction) : these limitations have not always been appreciated in the literature. (2) The simplest experiment displaying entanglements is based on viscometric flows at low shear rates. However, it has been recently realised that in many practical cases the standard boundary conditions - of zero slip at the walls - do not apply to these flows (9); when the wall is reasonably flat, and does not build strong links with the polymer, the friction forces involved in a finite slip are much weaker than the viscous stresses inside the polymer solution. This must, for instance, lead to strong deviations from the Poiseuille law in a capillary, whenever the tube diameter D is smaller than a characteristic length (of order 0.5 mm in typical cases). (3) A different approach is based on the studies of individual diffusion D* of a labeled chain, for which the reptation model (10) predicts a dependence of the form D* ∼ M-2 on molecular weight. Various systems have been used to measure D* (11) : here the emphasis will be on recent data using the stimulated Rayleigh effect (12) which is particularly well suited for slow diffusion.

Notes: The dynamics of polymer melts is well reflected in the complex shear compliance J*(ω,T,M) measured in wide ranges of frequency and temperature and for various molecular weights. In the frame of the meander model all typical features of J*(ω,T,M) are quantitatively described: (1) JeNo is due to intra-meander shear, and decreases by incorporating pairs of chain ends within the superstructure folds, i.e. with decreasing M. (2) This shear motion is guaranteed by a certain amount of edge-dislocations (with Burgers vector b equal to the chain distance d- for some polymers equal to d/2). The glass relaxation and its activation diagram are understood by asking for the probability for just this amount of dislocation segments to be present. The dielectric relaxation strengths and those of the thermal properties support the chosen segment lengths. (3) The step height to the steady state compliance, Jeo - JeNo (proportional to JeNo above MC, but strongly dependent on M-distribution), is due to inter-meaner shear (formation of shear bands). (4) These bands relax by disentanglement via chain reptation across half the length of a molecule within the flow relaxation time τF. (5) The Viscosity follows from η = τF/Δeo, and is proportional to M3.3 above and M1.3 below Mc. (6) The critical molecular weight Mc is predicated by the model in fair agreement with experimental data.(7) Neglecting flow, the stress-strain curves of uncrosslinked high molecular weight polymer metals can be derived by taking into account intra-and inter-meander shear deformation.

Notes: Experimental results are presented to show that suitable free radical sources, in combination with aryldiazonium, diaryliodonium, and triarylsulphonium salts, may be used to promote cationic polymerisation of alkyl vinyl ethers and cyclic ethers and cyclic ethers such as tetrahydrofuran. Mechanistic features vary between the different classes as monomer but a general feature is a free radically initiated chain reaction leading to formation of initiating or propagating cationic centres. The process is especially weil suited to use of photochemically active free radical sources and, for polymerisation of tetrahydrofuran, it is shown that at least thirty propagating cations are produced for each photon of light absorbed byu the free radical initiator β,β-dimethoxy-β-phenylacetophenone. Product studies confirm that the initiating free radicals undergo electron transfer oxidation.

Notes: The formation of a charge-transfer complex between 1-vinylindole (1a) and maleic anhydride (MA) was detected by 1H NMR analysis, and the corresponding Keq was measured (Keq=0,251 mol in CDCl3 at 25°C). It could be shown that this complex can be involved both in the initiation and propagation steps of the 1a-MA copolymerization by carrying out spontaneous copolymerization experiments and studying the influence of the feed composition on the conversion and [η] of the copolymer. The structure of the 1a-MA copolymer, investigated by 13C NMR spectroscopy, was found to be complicated due to the formation of indoline rings along the chains by an attack of the propagating MA radical at position 2 in the indole ring. As a consequence an excess of MA, with respect to a 1:1 mole ratio of monomer feed, was usually found in the copolymer. The mechanism of the cyclization reaction was clarified by copolymerizing MA with 2-methyl-1-vinylindole (1b), 3-methyl-1-vinylindole (1c), or 2,3-dimethyl-1-vinylindole (1d). An alternating copolymer with MA (mole ratio 1:1 of monomeric units), without irregularities, was obtained only by employing 1d as a comonomer.

Notes: Theoretical treatments of network formation and the applicability of the tree-like models to the calculation of structural parameters in the post-gel state and to more complex systems of practical importance are discussed. The unseparability of structural interpretation of network properties from network formation is stressed.

Notes: The characteristic fetures of isobaric volume and enthalpy recovery of glasses are briefly recalled and analysed in terms of a multiparameter model involving a distribution of retardation times, τi. The latter are assumed to depend both on temperature and on the instantaneous state (structure) of the glass, whereas the shape of the retardation spectrum is invariant and merely shifts, as τi, along the logarithmic time scale. Qualitative comparison of the theoretical predictions with various types of experiment reveals an excellent agreement. Some effects of structural recovery on the mechanical, or electrical properties of polymer glasses are also recalled and discussed in terms of the theoretical model The text which follows is merely an extended abstract of the work published elsewhere (see Refs 5 & 10)..

Notes: Recent advances and status of x-ray structure analysis of crystalline polymers are described using examples of α-modification of poly(ethylene oxybenzoate), poly(ethylene oxide), isotactic poly(methyl methacrylate), and cellulose I. Next the relationship between crystal structures and crystallite moduli (one- and three-dimensional) is discussed. Finally vibrational free energies of two crystal modifications of polyethylene are derived and discussed.

Notes: The author's Generalized Theory of Fracture Mechanics has been applied to several quite different polymeric materials which have in common a non-linear and inelastic deformation behaviour. Thus the normal Linear Elastic Fracture Mechanics cannot be applied. When applied to experimental data the theory provides a unique characterisation of fracture resistance and also sheds light on the molecular or microscopic fracture mechanisms of the material concerned.

Notes: While many well defined sequential copolymers have been synthesized by anionic and some by coordination polymerization techniques, cationic methods have not been exploited in this regard. This lecture focuses on “macromolecular engineering” by cationic techniques and summarizes the many recently developed and largely unpublished methods by which a great variety of sequential copolymers and modified polymers can readily be prepared. A new scheme for macromolecular engineering by carbocationic mechanism is proposed. Controlled initiation as a means of introducing head-groups into polymers or of graft-copolymer syntheses is described. Control of chain transfer to monomer became possible by the use of bifunctional initiator-chain transfer agents (inifers) or by proton sponges. The synthesis of telechelic α,ω-dichlorides, and -diolefins is outlined. α,ω-(Di-tert-chloro) polyisobutylene, a new symmetrical telechelic prepolymer has been used to prepare poly(α-methylstyrene-isobutylene-α-methylstyrene) thermoplastic elastomeric triblocks. Consequences of controlled termination are illustrated by the synthesis of diblock copolymers. Finally, by a combination of mechanistic elements, a system for macromolecular engineering by cationic techniques is outlined.

Notes: Stereospecific polymerizations of racemic mixtures of chiral cyclic monomers have been shown to be stereoselective with non chiral initiators and stereoelective with some chiral initiators.The bulkiness of the ring substituents influences the interaction of monomer with initiator and this leads to various kinetic schemes for stereoelective reactions, that may give efficient kinetic resolution of the monomer. In some cases a very strong effect of optical purity of monomer is observed in non racemic systems.Monomers having two chiral groups in the ring may be polymerized by an asymmetric polymer synthesis, giving optically active polymers starting from meso compounds.An analysis of several stereoelective processes leads to the conclusion that the monomer enantiomers play a major part in determining the chirality of the active centres.

Notes: In comparison to the number of publications on composition and structure of copolymers, there are only a few publications on the kinetics of radical copolymerizations. The equation by Melville and Walling is a first attempt to describe the kinetics. It was derived using the assumption that termination is chemically controlled. Since the 1960s it has been realized that in the case of radical polymerization reactions the chain termination is controlled by diffusion. Based on this knowledge Atherton and North developed a rate equation from which a termination constant can be ascertained from each monomer mixture composition. Russo and Munari continued North's works. They showed that the copolymerization rate can be adequately described if one assumes that the last two monomer units in the chain radical determine its segment flexibility. Apart from the constants known from the corresponding homopolymerizations the equation of Russo and Munari contains two other parameters, which are linearly connected. This equation was used in a discussion on copolymerization reactions in a homogeneous continuously stirred tank reactor (HCSTR). In this context the attainment of the steady state after disturbing input and output of the reactor was investigated.

Notes: The behaviour of polymers during stress relaxation at constant deformation is discussed. Special interest is devoted to the kinetics of the relaxation process and its physical interpretation. The various theories used in this field are compared, this comparison including in the first hand the theory of relaxation-time spectra and stress-aided thermal activation. Some discrepancies associated with these theories are pointed out, for instance the particular way in which the activation volume depends on the effective stress. Cooperatives effects are considered as a possible explanation of experimentally observed facts, especially with regard to the similarities in the stress relaxational behaviour of polymers and other solids, as for instance metals.The concept of effective stress incorporating the internal stress level is shown to be of primary importance in this context.

Notes: The presence of the crystals in the semicrystalline polymer reduces the mass fraction, determines the space distribution and modifies the transport properties of the amorphous component which is responsible for practically all the sorption, diffusion, and permeability. The conventional determination of the diffusion coefficient from the sorption or diffusion transient is strongly affected by the geometry of the sample. The spin echo method of the nuclear magnetic resonance in a pulsed magnetic field gradient measures the diffusion directly and hence reflects the anisotropy of the orientation of the amorphous component without any distortion by the shape of the sample. The anisotropy of a single amorphous layer of a thickness of less than 10 nm, however, cannot be detected by this method which measures the molecule displacement over about 300 nm.A very rough estimate of the transport properties of the volume element can be based on the fractional free volume of the polymer. This is particularly helpful in the description of the effects in elastically and plastically deformed material. The elastic tensional strain increases while the plastic strain as a rule decreases the free volume. In the latter case the amorphous component, at least at room temperature, permanently deviates from the thermodynamic equilibrium. A substantial part of this deviation can be removed by annealing. If the annealing of the fibrous material is performed with fixed ends which prevents shrinking the sample upon standing at room temperature tends to return, at least partially, to the transport properties before annealing.The sorption is proportional to the mass fraction of the amorphous component, the permeability to the square of it. The diffusion reflects the anisotropy of the morphology and of its influence on the transport properties of the amorphous component. In the fiber structure the amorphous layers parallel and perpendicular to the fiber axis differ substantially.In spite of the close connection between the morphology and the transport properties one must not forget that this connection is one-sided. A model of the structure with the proper transport parameters of the amorphous component has to yield the observed sorption and diffusion data. But these data are not sufficient for constructing unambiguously the structural model.

Notes: Highlights of recent research on the degradation and stabilization of polyolefins and poly(vinyl chloride) are outlined. The major defects in the molecular structure of poly(vinyl Chloride) are described and some controversial aspects of polyolefien photochemistry are discussed.

Notes: Applications of both polarized and depolarized dynamic light scattering to the study of polymers are described. Polarized light scattering is used to study translational diffusion, diffusion virial coefficients, rotational motion of long rod-shaped polymers, long-wavelength intramolecular motions, dynamics of pseudogels and gels and density fluctuations in bulk polymers. Depolarized scattering is used to study rotational diffusion of rigid macromolecules, local and long-wavelength intramolecular motions, dynamics in semi-dilute solutions, rotational motions of small molecules in glassy polymers and optical anisotrophy fluctuations of bulk polymers.

Notes: The statistical thermodynamics of the melt and the crystal are discussed by a unified approach which distinguishes between the two phases only in terms of a structure function minimizing the configurational free energy. The ensuing equations of state at atmospheric and elevated pressures are compared with typical experimental data for polymer and oligomer melts, and crystalline as well as semicrystalline systems, with satisfactory results. As to the glassy state, expansivity data clearly reflect nmot only the glass transition, but also sub-glass relaxation processes. In the spirit of the preceding discussion of the equilibrium melt, quasi-thermodynamic conditions are considered. Here the non-equilibrium character is reflected in the dependence of the extensive thermodynamic functions on thermal history in addition to the ambient variables of state. This state is discussed in terms of modifications of the liquid state model.

Notes: Some of the principles and advantages of affinity and polymeric drugs are demonstrated by the coupling by various methods of the anti-cancer drug daunomycin to antibodies against cancer cells and to dextran. In all the cases studied the conjugated drugs retain a significant amount of the original drug activity, and were less toxic. At higher concentrations the conjugated drug was more potent due to the lower toxicity. The mechanism of the action of the polymeric drugs are not yet known. We assume that they work through a slow release of the low molecular weight drug.

Notes: This paper deals with general and also specific aspects of matrix polyreactions on macromolecular templates, namely, mutual assistance of active centres of propagating chains and template units in elementry steps of propagatior. Such assistance has been found in polymerization of 4-vinylpyridine on polyacids and propargyl compounds on poly-4-vinylpyridine. These examples have shown that these kinds of assistance are the crucial points in kinetic template effects.

Notes: Different modes of interaction between the realm of photochemistry and photophysics and the domain of polymer chemistry are discussed. A distinction between photoinitiation and photopolymerization is drawn on the basis of the role of the excited state either in the chain starting or chain-growing process. Attention is drawn to specific properties or problems in the photochemistry and photophysics of macromolecules. The influence of neighbouring groups, high local concentrations etc. are discussed in relation to polymer transformation and excimer formation.

Notes: A survey is given on the actual knowledge about kinetics and mechanism of the synthesis of aromatic polyamides by dispersion polycondensation. Chemical activation of the reactants and swelling phenomena play an important role in this fast proceeding process. Molecular weight distribution of reaction products deviates from the most probable distribution.

Notes: In recent years thermodynamic equilibrium properties of amorphous polymer blends have been the subject of increasing interest. Experimental techniques, known in the study of polymer solutions, have been applied to blends and have been modified to deal with highly viscous systems. Determination of critical points, spinodal and cloud-point curves are now well possible by means of a low-speed centrifuge, pulse induced critical scattering and the centrifugal homogenizer.The classic Flory-Huggins model cannot describe the experimental results. Improvements can be made by the introduction of the contact surface areas of the segments, and by correcting the combinatorial entropy of mixing for orientational effects related to chain flexibility. Two-peaked spinodals may furthermore be described with a model accounting for three concentration ranges in the blend, the two dilute solutions of one polymer in the other and an intermediate range of uniform segment density. As a third possibility the introduction of holes in the lattice (simple lattice gas) can also lead to qualitatively correct descriptions, even in those cases where the phase diagram is still more complex (system poly(styrene-co-acrylonitrile)/polymethylmethacrylate) and shows three miscibility gaps.Strictly-binary polymer mixtures with a bimodal cloud-point curve should show two stable critical points. The fact that we did not find more than one may be attributed to polydispersity which easily shifts one of the critical points into the experimentally inaccessible meta-stable region.

Notes: Crystallization seggregation of chain ends and chains is always observed in oligomer multi-component systems. The driving forces of these processes can be classified by use of the thermodynamics of eutectoid systems. If folded-chain crystallization does not appear, a defined relationship between the chain length-and the crystal thickness distributions is predicted with its typical influence on the melting transition.With local equilibrium there is the opportunity for a quantitative description of the melting transition of eutectoid copolymers of ethylene by means of the same thermodynamics as used for the oligormers in spite of the existing crystal newtork. There is only need of taking into consideration a varied solubility in the microphases. Swelling phenomena are treated quantitatively on the same lines, thus, yielding the same relationship between the length distribution of the crystallizable sequences and the crystal thickness distribution as in the pure copolymeres.The melting transition is shown to depend on the swelling deformation in the non-crystallized regions which gives direct evidence for the existence of the molecular crystal network. Hence, local crystallization seggregation of non-crystallizable units is found to be in principles present in all the systems involved, thus, indicating its general importance.

Notes: 1Capabilities and limitations of methods for the determination of unperturbed macro - conformations in Θ - solutions as well as in metls and glasses are discussed, especially concerning the consequences for the micro-conformations. Quasi - isoenergetic polymer chains are concluded from thermolastic measurements on a configurätional copolymer.2Temperature dependent NMR- chemical shift measurements - beside those of coupling constants - are proposed for an independent determination of the micro - conformation on at a segemental level. Their populations are calculable from slow as well as from fast exchange spectra. Macro- dimensions as well as their temperature dependence as the consequence of the micro - conformations.3The dynamics of macromolecular chains - especially the anisotropy of motion - are discussed from NMR data.4The mechanism of stereospecific polymerizations as a consequence of conformational arrangements is discussed from NMR measurements.5Approaches to interpret thermal and mechanical data from configuration and conformation are reported.A short survey of the IUPAC lecture is presented, since detailed interpretation of the scientific work discussed either is given in the literature or will be published in the near future.

Notes: The polymerization of 1-(1-cyclopentenyl)vinyl acetate (1) and (3-methyl-1,3-butadien-2-yl) acetate (7) under radical conditions, leading to 1,4-polymers, and the copolymerization with vinyl monomers were studied. The reactivity ratios are compared with those previously described for some acetoxydienes. Polyketones and copolyketones were obtained by alkaline hydrolysis of the polymers of 1 and 7 and copolymers of 1 and 7 with styrene.

Notes: 1,4-Bis(2-diethylaminoethyl)benzene (4), synthesized from 1,4-divinylbenzene (1) and diethylamine (2) with lithium diethylamide as catalyst, was successively quaternized with 1,4-dibromobutane (5) to prepare a cationic polyelectrolyte 6 of the ionene type. Apparent molecular weights of the ionene samples were estimated by the sedimentation equilibrium method, and the result is discussed in connection with the true molecular weight. The rate constants for quaternization of first and second nitrogen atom of 4 (k1 and k2) were determined by the use of 13C NMR. It was found that the ratio of the rate constants, (k2/(k1/2)), markedly decreased in the 4/5 system, though it remained unity in the 4 ethyl bromide system.

Notes: The activated anionic polymerization of 2-pyrrolidone in the initial stage was studied at 30-70°C in the range of 1-60 min. Potassium tert-butoxide and N-benzoyl-2-pyrrolidone were used as initiator and activator, respectively. It can be seen from the polymerization process that side reactions occur parallel to the fast propagation reaction.

Notes: The polymerization of styrene initiated by titanium(III) chloride/alkyl halide redox systems was studied. Among the alkyl halides examined, the highest rate of polymerization was found in the system titanium(III) chloride/carbon tetrachloride. The polymerization rate can be described by the equation Rp=k·[Ti(III)]0,5·[CCl4]0,5·[St]1,0. The polymerization proceeded via a radical mechanism. The overall activation energy was estimated as 57,3 kJ/mol. It was found that titanium(III) chloride/chloroacetic acid systems, too, could initiate the polymerization of styrene.

Notes: N-vinylation of pyrazolecarboxylates and 1,2,3-triazolecarboxylates with vinyl acetate leads to the formation of the N-vinylpyrazoles and N-vinyl-1,2,3-triazoles. The structures are determined by mass and NMR spectra. The syntheses of crosslinked poly[1-(3,4-dicarboxypyrazol-1-yl)ethylene] (12) and poly[1-(4,5-dicarboxy-1,2,3-triazol-2-yl)ethylene] (13) are described. The swelling behaviour, the time dependence of the uptake of Cu2+-ions and the pH-dependence of the uptake of Cu2+-, Zn2+-, and Mg2+-ions of these resins were investigated.

Notes: Optically active poly(tert-butyloxirane)s of various molecular weights were prepared by polymerization of R(-)-tert-butyloxirane with different initiators or by stereoelective polymerization of the racemic monomer. Using identical conditions of polymerization (initiator, temperature etc.) it was found that the pure enantiomer polymerizes much faster than the racemic monomer. The chiroptical properties of the obtained polymers showed similarities in behaviour with those of a synthetized linear model molecule representative for a monomeric unit of the polymer. The enhanced optical activities of low molecular weight polymers were correlated with the presence of chelated hydroxylic end-groups.

Notes: In contrast to 13C NMR spectra, 15N NMR spectra allow one to characterize the sequence of copolypeptides built up by glycyl and β-alanyl residues, because the shifts of the Gly-Gly, β-Ala-Gly, Gly-β-Ala, and β-Ala-β-Ala bonds differ from each other by several p.p.m. Hence, the copolymerization of glycine-NCA and β-Alanine-NCA can be investigated by quantitative evaluation of the 15N NMR spectra obtained from the resulting copolymers. The copolymerization of these two amino acid NCAs initiated by primary amines leads to random sequences; the copolymerization is azeotropic in nature, and both copolymerization reactivity ratio parameters are near 1. If aprotic bases like pyridine and triethylamine are used as catalysts, the rate of incorporation of glycine is higher than that of β-alanine and the copolymers possess a block structure.

Notes: The polymerization of hexamethylcyclotrisiloxane (D3) was studied in methylene chloride solution in the presence of trifluoromethanesulfonic acid as catalyst. The reaction occurs mostly by addition of monomer to the ends of growing molecular chains. However, an important role is played by cleavage of a siloxane bond in the monomer by acid or water as well as by reverse processes of silanol and/or +ylester end group condensation to siloxane linkages. The latter account for the formation of large amounts of cyclic products and for the coupling of linear chain fragments. They are also responsible for the regeneration of the catalyst leading to establishment of stationary concentrations of reactive species in the polymerization system.The involvement of the above mentioned processes of condensation and siloxane bond cleavage contributes to a dramatic change in kinetics of the polymerization with introduction of water into the reaction system. In particular, the polymerization when carried out without water addition shows three interconnected features: 1 Strong acceleration of the rate with addition of small amounts of water to the system. 2 An apparent negative value of the activation energy. 3 Increase of the rate with decreasing initial concentration of the monomer. Above a certain level of water content the polymerization rate is only slightly dependent on the concentration of water. The energy of activation is 50 kJ/mol and the reaction is of 1st order in monomer, internally as well as externally.

Notes: The sequence polypeptides (Ala*-Ala-Gly)n, (Ala-Gly*-Gly)n, (Leu-Gly-Gly)n, (Val-Gly-Gly)n, and (Pro-Gly-Gly)n were synthesized by known methods, and their natural abundance 15N NMR spectra were measured in trifluoroacetic acid. These spectra were compared with those of other previously described sequence polypeptides and with the corresponding homopolypeptides. The spectra of all sequence polypeptides exhibit neighboring residue effects, so that glycine nitrogen atoms acylated by other χ-(or ω-)amino acids have chemical shifts different from that of the Gly-Gly bond. These neighboring residue effects cannot be summarized or explained by simple rules; however, they are useful for the characterization of copolypeptides. Such an application was tested in the case of four sequence polypeptides consisting of isomeric sequences of identical monomeric units. All isomeric sequences can be distinguished from each other, and the observed shift effects could be related to the neighboring residue effects of other copolypeptides.

Notes: The molecular weight dependence of the magnetic circular dichroism (MCD) for polystyrenes (PS) has been studied in various solvents by using the normalized dipole-strength D*. The normalized MCD intensity B* is not so much affected by the molecular weight as the normalized dipole strength D+. The ratio of the Faraday parameter to the dipole strength, B*/D*, decreases as the molecular weight increases to 4,0.103 and is constant above it. The increase of the normalized D* with the increase of molecular weight is interpreted in terms of the closer approach of chromophores. These results indicate that MCD for polystyrenes is influenced by the interaction of chromophores in a polymer chain: the decrease of B*/D* comes from the increase of the interaction of chromophores. This tendency is enhanced by solvent effects on MCD.

Notes: The anionic block copolymerisation of isoprene and 2-vinylpyridine (2VP) followed by a coordination with iron (III) chloride, leads to thermoreversibly crosslinked copolymers. These copolymers are character+ed by a low polydispersity (M̄w/M̄w≈1,1) between the coordination nodules of poly(2-vinylpyridine). The study of the swelling ratio at the equilibrium in benzene shows that such a polymeric network does not reach the equilibrium state expected from the thermodynamic analysis of the system. The presence of 2VP in the copolymer induces a screening effect which prevents the solvent diffusion through the polyisoprene network.

Notes: We tried to evaluate the reason for the very low polymerizability of methyl derivatives of 2-pyrrolidone in the presence of anionic polymerization catalysts. The polymerizability estimated from the influence of the methylated group on the reactivity of the lactam ring (steric, inductive, and thermodynamic factors) does not agree with the experimental results of homopolymerization and copolymerization of 2-pyrrolidone. The substitutional effects on the propagation process were analyzed and an explanation which is based on the slow-down of the molecular growth and the crystallization of the reaction mixture is proposed. Thus, in copolymerizations with a small percentage of substituted lactams, the propagation is very slow with regard to the crystallization, which would allow a quick encagement of the active site by hydrogen bonds, and lead to the spontaneous blocking of polymerization. If this percentage increases, the crystallization cannot take place, and this would, as a consequence. favor all the secondary reactions leading to the formation of bicyclic dimer and oligomers.A “chain multiplication” reaction was found in some cases.

Notes: A method is presented for inverting the Fredholm integral equations of the first kind that arise in many experimental determinations of molecular weight distributions of high polymers. The well known problems of instability and nonuniqueness are minimized by constraining the distribution to be the smoothest nonnegative one that is consistent with the data. Analyses of simulated photon correlation spectroscopy data show that good accuracy can be obtained for unimodal distributions and fair accuracy for certain bimodal ones, provided that systematic errors are kept below the random noise level. The method is completely automatic in that no initial estimate or prior information about the distribution is needed. However, if there happens to be a priori knowledge that the distribution is unimodal or that it is bimodal, constraining the distribution accordingly can further improve the stability and accuracy.

Notes: Several components have been found to be present in the 1H NMR absorption line in polycarbonate (poly(oxy-1,4-phenyleneisopropylidene-1,4-phenyleneoxycarbonyl)), swollen in carbon tetrachloride. The α-component, in the form of a Gaussian function is due to polymer chains present in areas with considerable degree of order. The intermediate β-component can be fitted with good accuracy by the calculated spectrum, by treating the magnetic dipole-dipole interaction as a perturbation of the proton two-spin system. The effect of second neighbours gives a finite width to components of that line. Such a type of fine structure determines with good accuracy the distance between two protons in the ortho-position in the phenyl ring executing some specific motions. Such phenyl rings can be present in tie-molecules of limited mobility performing a conformational reorientation motion. The γ-component is due to the micro-Brownian motion of polymer chains present in the system and also to lower molecular weight fractions of the polymer. This component can be generally described by an appropriate Lorentz function.

Notes: The melting temperatures of a syndiotacticity-rich poly(vinyl alcohol)-water gel were measured for concentrations below 70g.dm-3. In the gel chilled at a temperature below about 15°C the melting point first decreased monotonously then sharply in a jump and again monotonously with decreasing concentration, whereas in the gel chilled above 20°C the melting point decreased monotonously through-out. The change of the shear modulus of a gel chilled at 0°C with the rise of temperature from 0°C to the melting point was also measured. Initially the shear modulus decreased, then increased to a maximum value, and at last decreased towards the melting temperature, whereas a gel chilled at 40°C kept an almost constant value during heating from 40°C up to a high temperature and then decreased with further rise of temperature. The turbidity of dilute solutions chilled at 0°C passed a minimum and maximum with the rise of temperature in accord with the minimum and maximum of the shear modulus. It is thus concluded that in the gel chilled at temperatures below 15°C the junctions grow to some extent with the rise of temperature.

Notes: The crystallization kinetics of binary blends of samples of poly(ethylene oxide) with different molecular weights, namely 2000, 20 000, and 197000 has been investigated by means of polarized light microscopy in order to establish the dependence of the kinetic parameters upon the composition. The temperature and composition dependence of the growth rates of spherulites in thin films of supercooled melt has been analyzed by means of the theoretical expressions given by Hoffman and Lauritzen. The experimental results indicate that some kinetic and thermodynamic quantities such as the rate of crystallization, the equilibrium melting temperature, the free energy of formation of a nucleus of critical size, and the surface free energy of folding are strongly dependent upon the composition of the blends.

Notes: 2D NMR spectra have been measured at variable temperatures between -100°C and +110°C in a sample of melt crystallized deuterated polyethylene (PE). The line shape could be decomposed into a central part originating from deuterons in the amorphous regions and outer parts from crystalline regions of PE. The “NMR crystallinity” determined from this separation was 72% in agreement with the X-ray crystallinity of 74%. Changes of the crystalline NMR line shape were interperted in terms of oscillations around the chain axis, the r.m.s. oscillation amplitude varying from 5° at 40°C to 12° at 110°C. The central part of the NMR line shape indicates the existence of a “narrow” and a “medium” component due to different motional processes in the amorphous regions.

Notes: Oxidation of tertiary amines with N-chloronylon 66 (NCN) was investigated in several organic solvents. NCN was found to oxidize N,N-dimethylaniline (DMA) at room temperature to give N-methylaniline with 15-50% yield, depending on the solvents used. Oxidation of N,N-dimethylbenzylamine (DMBA) gave benzaldehyde with 15-30% yield and a small amount of N-methylbenzylamine. A mechanism was discussed. For comparison, N-chlorosuccinimide, a low molecular N-chloro-compound, was also used for oxidation of DMA and DMBA.

Notes: A series of active β-alanine 4-acyl-2-nitrophenyl esters with different lengths of alkyl groups was prepared, and their polycondensation was studied in various solvents. The results of the polycondensation of these esters with triethylamine at room temperature show that the conversion and the degree of polycondensation of the resulting poly(β-alanine)s depend on the chain length of the alkyl groups. No polymer was obtained in both protic and dipolar aprotic solvents such as methanol and DMSO, whereas nonpolar solvents such as diethyl ether, carbon tetrachloride, or benzene were found to be suitable for the polycondensation. The effect of a variety of amines on the polycondensation was examined for β-alanine 4-dodecanoyl-2-nitrophenyl ester (4e) in diethyl ether solution.

Notes: Partially hydrogenated 1,4-polybutadiene is degraded into GC-detectable reaction products after olefin-metathesis with 4-octene in the presence of WCI6/(CH3)4Sn. 1,4-polybutadiene is homogeneously hydrogenated with p-toluenesulfonohydrazide and serves as copolymer with non-hydrogenated and hydrogenated repeating units. Hydrogenated sequences up to an undecade are detectable. The experimental monomer sequence length distribution agrees satisfactorily with the theoretical one calculated under the assumption of an ideal statistical copolymer.

Notes: 2-(1,3-Dimethyl-2,6-dioxo-2,6-dihydropurin-7-yl)methylsuccinic acid (2a) and 2-(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)methylsuccinic acid (2b) were synthesized via the addition reaction of theophylline and thymine, respectively, to dimethyl methylenesuccinate, followed by hydrolysis of the resulting ester. The dicarboxylic acid derivatives 2a and 2b were further converted to their di-p-nitrophenyl esters 3a and 3b, which were allowed to polycondense with diamines such as 1,6-diaminohexane, 1,2-diaminoethane, 3-aminomethylbenzylamine, and piperazine in solutions. The resulting polyamides are white powders with molecular weights in the range of about 2000-6000. The DP of the polyamides varies with the kind of diamines and solvent used. All polyamides are soluble in DMSO and formic acid, the polyamides deriving from esters 3a and 3b and 1,2-diaminoethane and piperazine are also soluble in water.

Notes: Styrene isoprene styrene copolymers (SIS) modified by epoxidizing were investigated in order to obtain adhesive materials. Influences of experimental parameters (concentrations, solvents, compositions of SIS) are shown for epoxidation with monoperoxyphtalic acid at a yield of modification lower than 50%.

Notes: It was found that the formation constants (K) of CuX(QPVP)n- (X = ethylenediaminetetraacetate ion (edta) and N-(2-hydroxyethyl)ethylenediamine-N,N′,N′,-triacetate ion (hedta), QPVP = partially quarternized poly(4-vinylpyridine)) increase sharply with increasing degree of quarternization (Q) of QPVP. In the Cu(edta)2-/QPVP system. K values are 481.mol-1 for Q = 0%, 8701.mol-1, for Q = 25%, and 1,1.103l.mol-1 for Q = 61%, in aqueous methanol (volume ratio 1:1) at μ = 0,1 mol.l-1, pH = 8,0. and T = 25°C. In the system CH3Co(dmg)2H2O/QPVP, K decreases linearly with increasing degree of quarternization of QPVP from K = 1,7.103l.mol-1 for Q = 0% to K = 95l.mol-1 for Q = 61% in aqueous methanol (volume ratio 3:7) at μ = 0,05, pH = 8,0, and T = 25°C. The decrease in K is +scribed to a relatively large decrease in the rate constant of the forward reaction and a small increase in that of the backward reaction.

Notes: The method of gel permeation chromatography was used to study the structural changes of poly(2,6-dimethyl-1,4-phenylene oxide) in the course of thermooxidative degradation. During the degradation two principal processes occur: random scission and crosslinking. The latter process leads to the formation of insoluble fractions. The reaction rates and activation energies of both processes have been determined. The mechanism of degradation as well as the influence of some additives is discussed on the basis of experimental data.

Notes: Hemiporphyrazine type macroheterocycles with 2,2′-bi-1,3-dithiolylidene (tetrathiafulvalene) units in the polymeric chains (3a-e) were obtained by reaction of 2,2′-bi-1,3-dithiolylidenetetracarbonitrile (tetracyanotetrathiafulvalene) (1) with several diamines (2a-e). The black polymers were characterized by elemental analyses and IR spectra. Thermoanalytic measurements showed that decomposition starts without melting at temperatures 〉 300°C. The polymers were found to be polymeric organic semiconductors with activation energies of 0,6-1,4eV and electrical conductivities in the range from 10-14 to 10-10Ω-1.cm-1. In the case of the polymers 3a and 3b it was possible to obtain metal complexes (4a-b) by substituting the two hydrogen atoms inside the macroheterocyclic rings. Depending on the metal atoms the electrical conductivities were enhanced up to two orders of magnitude.

Notes: A series of new catalytic systems ZnEt2/cocatalyst were prepared and their activity in the alternating copolymerization of carbon dioxide with propylene oxide was studied. The systems ZnEt2/m-HXC6H4XH (mole ratio 1:1) system (X = NH, S) were chosen to elucidate the influence of the heteroatom on the activity of the catalytic system. The obtained results were discussed in terms of the influence of the basicity of the heteroatom and of its hybridization on the structure and association of the catalyst molecule.

Notes: Succinic esters of starch and dextrane (STS and DTS) have been prepared and transformed into the corresponding imidazolides. These are difficult to isolate in a pure state. Without previous isolation, however, they react smoothly with alcohols or amines giving the corresponding polymeric esters or amides. STS benzotriazolide has also been prepared, and isolated in a pure state. It has been found to have the same reactivity towards alcohols and amines than other previously described polymeric benzotriazolides. These results demonstrate that STS or DTS activated amides offer new opportunities to prepare polymer drug adducts with a main backbone degradable to safe metabolites in the body fluids.

Notes: Conformational transitions of histones F1 (H1), F2a (H2A), F2b (H2B), and F3 (H3) in the presence of carcinogens 4-nitroquinoline-N-oxide, 13-H-dibenzo[c,j]carbazole, and 7-H-dibenzo[c,q]carbazole were studied by the circular dichroism (CD) probe. The polypeptide main chain conformation of the very lysine rich histone F1 was not affected by these carcinogens, but the tertiary structure was modified slightly by the carbazoles. The secondary structure of histone F2a was significantly modified by the carbazoles which enhanced the helix content, whereas the effect of the 4-nitroquinoline-N-oxide on the backbone conformation was weak. The tertiary structure of F2a was affected by all three carcinogens, whereby the 7-H-dibenzo[c,g]carbazole produced the strongest enhancement of the CD bands assigned to tyrosine and phenylalanine chromophores. Moreover, this carcinogen produced extrinsic Cotton effects in the 300-380nm spectral zone. Similar effects of the carbazoles were observed with histone F2b, although in this case the main chain conformation was changed only slightly. The secondary structure of histone F3 was slightly affected by the carcinogens but the tertiary structure was significantly modified by the carbazoles. The CD bands of F3 which were assigned to the tyrosine and phenylalanine chromophores were most strongly enhanced by the 13-H-dibenzo[c,j]carbazole.

Notes: The structure of AB block copolymers with a polydiene block (polybutadiene or polyisoprene) and another block (polystyrene, poly(α-methylstyrene)), poly(2-vinylnaphthalene), poly(2-vinylpyridine) or poly(4-vinylpyridine) was studied by low angle X-ray diffraction and electron microscopy. The influence of the nature of the non-diene block (styrene, α-methylstyrene, 2-vinylnaphthalene), the nature and the microstructure of the diene block and the isomery of the vinylpyridine block on the parameters of the lamellar structure and the conformation of the macromolecular chains was established.

Notes: The binding of acridine orange to carboxyl and sulfate containing polyanions has been investigated by fluorescence spectroscopy. Particular attention has been given to solutions containing both carboxyl and sulfate groups in two different situations, first where both types of site are present attached to the same polymer backbone in a regular repeating structure (heparin), and secondly where individual polymer chains carry exclusively one type of site (hyaluronic acid/K-carrageenan mixtures). Greatly differing behaviour of the binding profiles as the concentrations of components were reduced have been explained in terms of the strong co-operativity of the dye-binding process. The carboxyl and sulfate sites of heparin appear to be equivalent in binding strength, while those of the polycarboxylate polysulfate mixture are no longer equivalent, binding profiles being dominated by the strong binding sulfate group.

Notes: The examination, by 1H NMR, of anionic hydroxytelechelic polybutadienes in conjunction with accurately measured Mn values allows the simultaneous determination of the number average functionality and the identification of the nature of the chain ends bearing the functional groups. The microstructure of the polymer chains has been studied by 13C NMR. A high proportion of isolated vinyl units has been found only if the percentage of vinyl is less than 70%, whereas the vinyl sequences are atactic. During the functionalization, if lithium is utilized as catalyst, only one molecule of ethylene oxide is added at each end of the polymer chain. With potassium, ethylene oxide polymerizes. Owing to the chain ends, reaction mechanisms of the addition of ethylene oxide onto the living polymer have been proposed.

Notes: This paper describes how a classical light scattering apparatus (FICA 42000) can be modified in order to allow measurements with red light using a gas laser. This apparatus is calibrated, and experimental results are compared with the theoretical results. The advantages of such measurements are that, when red light is used, one has no fluorescence problems, and the properties of the laser (i.e., collimation, stability and illumination) allow the possibility of simultaneous measurements of both gel permeation chromatography (GPC) and light scattering.

Notes: The mechanical degradation of polyacrylamide and dextran and the acid hydrolysis of dextran at different pH values is investigated in concentrated solutions in high shear laminar flow fields. The kinetics of degradation of polyacrylamide show that the reaction is first order, the rate constants of degradation are proportional to the molecular weight, and the polymer molecules are broken preferentially near the center of the chain. It is found that shear stress is the controlling factor of the degradation process, the rate constants increasing in poor solvents and with decreasing temperatures. The limiting molecular weight is a direct function of the shear stress. For dextran a transition range exists in which shear degradation is favored by hydrogen ions at pH values at which no hydrolysis occurs in the absence of a shearing field.

Notes: A series of α,α-disubstituted β-propiolactams (substituted nylon 3 polymers) was prepared from non-optically active lactams. Their thermal characteristics, densities, and x-ray fiber diffraction patterns were recorded. One of the α-substituents was always a methyl group while the other was either CH3, C2H5, n-C3H7, or n-C4H9. The melting point for the dimethyl substituted polymer was 268°C; the others were respectively 76, 74, and 72°C. X-ray fiber diffraction data on all four samples yielded the same fiber repeat of ≈8,4 Å. A minimum energy based conformational analysis for the α,α-dimethyl derivative indicates that two conformations correspond to this repeat, each of which is a 21 helix.

Notes: The change of the radial structure during the diffusion of dyestuffs in fibers of poly(ethylene terephthalate), [poly(oxyethyleneoxyterephthaloyl)], is studied with regard to the relationship between the dyestuff diffusion and the structure of high polymers. The fiber structure is described by interferometric measurements, which allow statements about order and orientation as a function of the diffusion path. The experimental results show that C. I. Disperse Red 60 raises the parameters which describe the order and orientation and that C. I. Disperse Blue 139 lowers these structure parameters.

Notes: Dilute solution properties of poly(2-biphenylyl methacrylate), (poly[1-(2-biphenylyloxycarbonyl)-1-methylethylene], POB) were studied by viscosity, sedimentation, light scattering and osmotic pressure in different solvents. The solvent dependence of intrinsic viscosity, [η], Huggins constant, KH, Mark-Houwink exponent, a, and expansion factor, αη, is very weak, although the chemical nature of the solvents is quite different (CHCl3, tetrahydrofuran, benzene, 1,4-dioxane). For poly(4-biphenylyl methacrylate) (poly[1-(4-biphenylyloxycarbonyl)-1-methylethylene], PPB) and other aromatic polymethacrylates the changes of [η], KH, a and aη are very high. The unperturbed dimensions calculated from viscometric and light scattering data by different methods, are in excellent agreement with one another and good agreement with those obtained from sedimentation data. POB has a higher flexibility factor (σ = 2,8) than PPB (σ = 2,7). In our opinion this is due to the fact that the 2-biphenylyl group is closer to the main chain than the 4-biphenylyl group. The very high value of σ explains the weak solvent dependence of [η], KH, a and αη in the case of poly(2-biphenylyl methacrylate).

Notes: The heterogeneous polymerization of L-proline N-carboxy anhydride was carried out in acetonitrile and benzene, using butylamine as the initiator. Polyproline I was formed in acetonitrile and polyproline II in benzene in the course of the polymerization. The conversion attained 99% and 66% after 1 week-polymerization in acetonitrile and benzene, resp. Extended chain crystals were obtained by the polymerization in acetonitrile. On the other hand, poly(L-proline) obtained by the polymerization in benzene gave aggregates into which many growing chain ends were occluded. The differences in the crystallization behaviour during the polymerization between the two different liquids may be due to the conformation of the resultant polymers. Polyproline I exhibits a cross-section per chain of 0.709 nm2, whereas polyproline II shows only one of 0,386 nm2. The wider the cross-section per chain the more the growing, active chain ends can react with the monomer, giving rise to a higher conversion. In contrast with the case of crystallization of such α-helical chains as poly(L-alanine) during polymerization, hexagonal lamellar crystals were formed.

Notes: Concentration distributions of dyestuffs C. I. Disperse Red 60 and C. I. Disperse Blue 139 in microtomic cuttings of fibers of poly(ethylene terephthalate), (poly(oxyethyleneoxyterephthaloyl)) are discussed. An interpretation of the results in relation to order and orientation along the fiber radius by interferometric investigations gives informations about the diffusion process. It is shown, that the diffusion of dyestuffs in high polymers depends - in a complicated way - on fiber structure (as a function of the diffusion path), fiber history, and experimental conditions: C. I. Disperse Red 60 shows a lower diffusion rate at higher radial orientations, whereas the diffusion rate of C. I. Disperse Blue 139 does not depend on the radial dependence of these structure parameters.

Notes: Methacrylic acid esters having two different and same kinds of nucleic acid bases such as theophylline-theophylline, theophylline-thymine, theophylline-uracil, and uracil-uracil, were synthesized, and polymerized in DMF or DMSO at 70°C using 2,2′-azoisobutyronitrile as an initiator. The polymers obtained were found to have molecular weights in the range of about 1800-4000, according to vapor pressure osmometr y and gel filtration measurement. The white powdery polymers were soluble in DMSO, DMF, and trifluoroacetic acid, but insoluble in water, alcohols, and common organic solvents.

Notes: The kinetics of polymerization of acrylamide initiated by potassium peroxodisulfate, in the presence and absence of Ag(I) and Cu(II) ions, was studied. The rate law for the polymerization was established. Cu(II) ions were found to reduce both the rate and degree of polymerization.

Notes: The reaction of a nitrile (acetonitrile) with a metalated amine (aniline and benzylamine) was attempted, in order to obtain the corresponding amide via hydrolysis of the amidine. This reaction was also applied for the preparation of polyamides, using diamines and dinitriles. The reaction of aliphatic diamines with aliphatic dinitriles yielded 20-30% of polyamides of low degrees of polymerization.

Notes: Polycarbonate 3 was synthesized by copolymerisation of 4-(p-hydroxyphenylisopropyl)phenol with [3,5-Bis(hydroxymethyl)phenylazo]-methylmalonodinitrile (2a). This azo groups containing polycarbonate was employed as initiator for graft copolymerisations. The content of azo functions in the resulting copolymers was determined by 1H NMR, microanalysis, and DSC-measurements, and Mn by vapor pressure osmometry. Grafting was carried out with styrene in 1,4-dioxane and the resulting products were characterized by IR, 1H NMR, HPLC, and vapor pressure osmometry.

Notes: Sulfadiazinacrylamid was absorbed after oral and intraperitoneal application in rats to a high extent; the absorption from the intraperitoneum was retarded. Glucose treatment delayed the absorption after both application forms. At comparatively high renal and enteral excretion rates the biological half life time of the monomer was estimated to 8 h. A tumouraffinity was not found but there were indications for a preferred storage in the RES.Poly[sulfadiazinacrylamide] was absorbed after intraperitoneal injection to a clear extent, where at the beginning of the treatment under simultaneous glucose load the absorption was delayed. 24 h after injection higher concentrations in metabolic organs and those of the RES were established. After oral application of the polymer an effective resorption was excluded. The elimination of the intraperitoneally injected polymer happened at negligibly low dose rates; after oral application the elimination process was finished within 24 h after treatment of the test animals. The polymer showed no tumouraffinity.

Notes: The dependence of the apparent dissociation constant and of intrinsic viscosity on the degree of dissociation of 2-hydroxyethyl methacrylate-methacrylic acid copolymers was investigated. It was found that the conformational transition indicated in the potentiometric titration was distinct only with copolymers containing at least ca. 48 mole% of methacrylic acid. The transition is probably related with the local configurational and conformational structure while being uncorrelated with the transition of the coiled form of the macromolecule into the expanded one.

Notes: The free radical copolymerizations of 6,8-dimethyl-4-oxo-5-chromanylmethyl acrylate (DCA) with styrene (St), methyl methacrylate (MMA), and vinyl chloride (VC) by the solution polymerization method were studied. For copolymerization of DCA(M1) with St(M2), the reactivity ratios were r1=0,32, r2=0,70; with MMA(M2) they were r1=0,43, r2=2,00; and with VC(M2) they were r1=4,00, r2=0,08. The Q and e values for DCA were 0,54 and 0,42, respectively. It was also shown that the chromanone skeleton acts as UV-absorber, and inhibits photodegradation of the copolymers.

Notes: Nascent polyethylene with high molecular mass (Mn ≈ 105, Mw ≈ 106) produced in hydrocarbon medium in presence of TiCl4/(C2H5)2AlCl/(C6H5)2Mg catalyst was studied by means of X-ray diffraction, electron and light microscopy, and low-angle light scattering. It consists of porous spherulite-fibril aggregates indicating a not very high degree of crystallinity α(α≈). Data, concerning the dependence of spherulite dimensions, degree of crystallinity and other structure parameters of nascent polyethylene on polymerization time and temperature are discussed. Using the same structure-analytical methods some samples of nascent polyethylene were studied after annealing them in nitrogen atmosphere at different temperatures between 110-250°C with successive cooling to room temperature. Furthermore both the endo- and exothermal transitions occurring in the nascent and annealed structures after heating to 250°C were studied by means of DTA and DSC. The experimental information leads to the conclusion that nascent polyethylene structures consist of crystalline folded chain lamellae with an increased amount of tie molecules between them as well as of extended chain crystals.

Notes: From theoretically and experimentally obtained light scattering cross sections of some polystyrene solutions and the discrepancy between theory and experiment the question of correlated fluctuations of the components of the scattering tensor δεik is discussed. It is found that this discrepancy can be explained only in part by the consideration of the intermolecular interference effects and the supposed change of the scattering cross section of the solvent in the solution.

Notes: The sequence distribution of inverted monomeric units in the stereoirregular polypropylenes, prepared with the TiCl4/Al(C2H5)3 catalyst system, has been examined by 13C NMR. Observed dyad and triad sequence distributions were in good agreement with those calculated from first-order Markov statistics. The regioselectivity of an inserting propene seems to depend not only on the polarity of the active carbon-titanium bond but also on the steric effects of the last propylene unit of a growing chain.

Notes: The effect of desorption of monomer radicals from particles on the particle number generated in interval I of an emulsion polymerization is calculated by means of a semi steady state model. It is shown that desorption leads to an increase in the particle number, and at the same time the orders of particle number with respect to emulsifier and initiator are changing. The general equation of Nomura N∝Sz0ϱ1-zi is found to apply, z increasing from 0,6 to 1,0 with increasing desorption. The values of z and N are dependent on the exact reaction mechanisms in the monomer/polymer system and on rate constants of chemical reactions and diffusion processes involved in the particle formation.

Notes: The effect of some solvent/nonsolvent pairs on the efficiency of the column fractionation of polystyrene was investigated. Extensive cloud point titration experiments were shown to be needed for the correct assessment of thermodynamic qualities of a solvent/nonsolvent pair used in the column fractionation of polymers. Besides the thermodynamic suitability of solvent pairs their kinetic behavior was shown to differ. Possible reasons for the observed differences were discussed.