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1

Digitale Medien

Methacrylate-based block ionomers I: Synthesis of block ionomers derived from t-butyl methacrylate and alkyl methacrylatesDedicated to Professor Maurice Morton to commemorate the establishment of the Maurice Morton Institute of Polymer Science at the University of Akron. (1994)

Deporter, Craig D. ; Long, Timothy E. ; McGrath, James E.

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 33 (1994), S. 205-216

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ISSN: 0959-8103

Schlagwort(e): block ionomer ; anionic polymerization ; methacrylates ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: Diblock and triblock copolymers of t-butyl methacrylate (tBMA) with 2-ethylhexyl methacrylate (EHMA) and n-hexyl methacrylate were prepared via alkyl lithium initiation and sequential addition techniques in THF at -78°C. The tBMA blocks were quantiatively and selectively hydrolyzed to afford poly(methacrylic acid) (PMAA) blocks which were then neutralized with alkali metal bases to form block ionomers. The unhydrolyzed copolymers had a phase mixed morphology as evidenced by thermal analysis while the hydrolyzed and neutralized polymers were multiphase materials. The carboxylic acid and ioncontaning triblock copolymers formed gels in nonpolar solvents which could be disrupted by the addition of polar additives. Certain carboxylic acid and ioncontaining EHMA/tBMA diblock copolymers also showed this behavior. The triblock ionomers did not show thermoplastic flow prior to degradation, except at the lowest ionic content studied (2%).

Zusätzliches Material: 8 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210330212

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2

Digitale Medien

Synthesis and properties of polydiacetylene-containing polyesters (1994)

Lovell, P. A. ; Stanford, J. L. ; Wang, Y-F. ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 34 (1994), S. 23-33

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ISSN: 0959-8103

Schlagwort(e): polyesters ; diacetylenes ; cross-polymerisation ; DSC ; Raman spectroscopy ; tensile deformation ; Raman shift factors ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: A series of diacetylene-containing polyesters with number-average molar masses (GPC) in the range 900-4200 g mol-1 were prepared from terephthaloyl chloride and hexa-2,4-diyne-1,6-diol using benzoyl chloride as a monofunctional reactant for control of molar mass. Degrees of crystallinity were estimated from WAXD to be up to 29%. Correlations between molar mass, melting behaviour, degree of crystallinity and thermal cross-polymerisation of diacetylene-containing polyesters have been established using hot-stage microscopy, DSC and resonance Raman spectroscopy. The polyester with M̄n of 1264 g mol-1 gave the best balance between processability and the ability to cross-polymerise efficiently. Its degree of crystallinity before cross-polymerisation was estimated from WAXD measurments to be 24%, a value coincident with the percentage conversion of diacetylene units to polydiacetylene chains measured by 13C solid-state NMR. The optimum conditions for compression moulding the polyester to produce a material with a strong Raman spectrum involved heating under vacuum at 120°C for 6h after an initial 3 h heat-up period. The material thus produced gave an intense Raman C=C stretching band, which upon tensile deformation shifted linearly with strain to lower wavenumber by 12.0 cm-1 %-1. The potential use of the diacetylene-containing polyesters in the preparation of model blends for use in quantitative micromechanics studies of stress transfer between phases is briefly discussed.

Zusätzliches Material: 9 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210340105

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3

Digitale Medien

Anionic polymerization of octamethylcyclotetrasiloxane in aqueous emulsion I: Preliminary results and kinetic study (1994)

De Gunzbourg, Anémone ; Favier, Jean-Claude ; Hémery, Patrick

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 35 (1994), S. 179-188

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ISSN: 0959-8103

Schlagwort(e): anionic polymerization ; octamethylcyclotetrasiloxane ; emulsion ; α,ω-dihydroxy polydimethylsiloxane ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: The synthesis of poly(dimethylsiloxane) (PDMS) by anionic polymerization of octamethylcyclotetrasiloxane (D4) in aqueous emulsion using an emulsifying agent acting also as initiator (benzyldimethyldodecylammonium hydroxide) is described. Stable emulsions of α,ω-dihydroxy PDMS with an easily controlled molar mass (up to 15 000), a low polydispersity index and high yields were obtained. The amount of cyclics formed (essentially D4 to D7) is lower than that observed in bulk. Kinetics analysis and computerized simulations are in good agreement with a reaction scheme involving simultaneous polyaddition/polycondensation processes. At high monomer consumption, polycondensation predominates leading to a broadening of the molecular weight distribution (MWD). The apparent rate constants of initiation, propagation and condensation at various temperatures and the corresponding activation energies were determined.

Zusätzliches Material: 10 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210350208

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4

Digitale Medien

A hydrocarbon-soluble difunctional orgaolithium anionic initiator. Synthesis of 2,2-bis[3-(1-lithio-2,3-dimethylpentyl)-4-methoxyphenyl]propane (1994)

Sanderson, Ronald D. ; Roediger, Andrew H. A. ; Summers, Gabriel J.

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 34 (1994), S. 163-171

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ISSN: 0959-8103

Schlagwort(e): anionic polymerization ; 2,2-bis[3-(1-propenyl)-4-methoxyphenyl]-propane ; difunctional initiator ; organolithium ; intramolecular ether linkage ; nonpolar solvents ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: The reaction of stoichiometric amounts of sec-butyllithium with 2,2-bis[3-(1-propenyl)-4-methoxyphenyl]propane (4) produces a new difunctional organolithium initiator, 2,2-bis[3-(1-lithio-2,3-dimethylpentyl)-4-methoxyphenyl] propane, which is soluble in hydrocarbon solvent in the absence of any polar additive. Following isolation and purification by gas liquid chromatography, the structures of (4) and the methanolysis product of the difunctional initiator were characterized by 1H NMR, FTIR and mass spectroscopy and elemental analysis. The dilithium initiator is effective for the polymerization of 1,3-butadiene and allows the preparation of polybutadienes with predictable molecular weights, narrow, monomodal molecular weight distribution and low 1,2-diene microstructure.

Zusätzliches Material: 5 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210340207

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5

Digitale Medien

Influence of the chemical modification of phenoxy resin on its miscibility with poly(2-vinyl pyridine)Presented in part at a conference on Polymer Spectroscopy Grasmere, UK, 28 March-1 April 1993. (1994)

Eguiburu, J. L. ; de Ilarduya, A. Martinez ; Iruin, J. J. ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 33 (1994), S. 393-398

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ISSN: 0959-8103

Schlagwort(e): phenoxy resin ; poly(2-vinyl pyridine) ; miscibility ; FTIR ; DSC ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: The influence of the chemical modification of the hydroxyl groups of phenoxy resin (PH) by benzoate, acetate and methoxy groups on its miscibility with poly(2-vinyl pyridine) (P2VPy) is investigated. Both DSC and FTIR results permit the definition of three distinctive regions: up to 40% modification all 50/50 blends are miscible; between 40 and 55% modification all blends present partial miscibility and at higher than 55% modification the blends are totally immiscible. Specific interactions between the hydroxyl groups of PH and the amine groups of P2VPy are put forward as an explanation for these observations.

Zusätzliches Material: 7 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210330409

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6

Digitale Medien

Effect of addition of organoaluminum and organoboron compounds in the stereospecific polymerization of acrylonitrile using dialkylmagnesium as catalyst (1994)

Nakano, Yasuhiro ; Hisatani, Kunio ; Kamide, Kenji

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 34 (1994), S. 397-405

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ISSN: 0959-8103

Schlagwort(e): stereospecific polymerization ; polyacrylonitrile ; tacticity ; dialkylmagnesium ; alkylaluminum ; additive ; anionic polymerization ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: An attempt was made to clarify the effect of addition of organoaluminum and organoboron compounds in the stereospecific polymerization of acrylonitrile (AN) initiated by dialkylmagnesium (R2Mg) above 100°C. The triad isotacticity (i.e. the content of mm (m: meso)) as well as the viscosity-average molecular weight (M̄v) of polyacrylonitrile (PAN) increased when trialkylaluminum (R3Al) and trialkylboron (R3B) were used as additives. Diisobutylaluminum hydride [(i-C4H9)2AlH] was found to be the best additive. in the stereospecific polymerization of AN, giving PAN with higher (mm) content (0.63), higher M̄v value (5.2 × 104), and a yield approximately double that obtained using (n-C6H13)2Mg alone. When the (n-C6H13)2Mg/(i-C4H9)2AlH system was used, the yield, (mm), and M̄v of PAN increased with polymerization temperature (Tp); maximum values of yield, (mm), and M̄v were obtained at c. 130°C. The optimum amount of additives was approximately equimolar to R2Mg as initiator. The 13C chemical shift of α-carbon in R2Mg at 90°C shifted by mixing with R3Al and R3B, respectively, indicating the existence of interaction between R2Mg and the additives. The main role of the additives is considered to be suppression of the self-association of R2Mg by strong interaction with R2Mg.

Zusätzliches Material: 5 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210340408

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7

Digitale Medien

Hydrocarbon-soluble difunctional organolithium anionic initiators. A gas-liquid chromatographic study of the reaction of sec-butyllithium with m-divinylbenzene (1994)

Sanderson, Ronald D. ; Roediger, Andrew H. A. ; Summers, Gabriel J.

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 35 (1994), S. 263-272

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ISSN: 0959-8103

Schlagwort(e): anionic polymerization ; 1,3-bis(1-lithio-3-methylpentyl)benzene ; gas-liquid chromatography ; high purity sec-butyllithium ; difunctional initiator ; nonpolar solvents ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: Quantitative gas-liquid chromatography provides an efficient, novel technique for the kinetic study of the reaction between sec-butyllithium and m-divinylbenzene. The reaction of stoichiometric amounts of ultra-high purity sec-butyllithium with pure m-divinylbenzene at -23°C produces an anionic initiator, 1,3-bis(1-lithio-3-methylpentyl)benzene, 2, without traces of monofunctional and polyfunctional impurities. The relative rates of formation of 2 with and without the presence of Lewis base, triethylamine, or Lewis acid, diethylzinc, were studied by gas-liquid chromatography. The presence of diethylzinc reduces the activity of sec-butyllithium to such an extent that the reaction did not proceed beyond the monofunctional component stage, that is, the formation of m-1-lithio-3-methylpentylvinylbenzene, 1. The reaction of sec-butyllithium with m-divinylbenzene at -79°C with a 10mol% ratio of triethylamine to sec-butyllithium yielded a homogeneous product with composition of 94% difunctionality and 6% monofunctionality, with the total disappearance of m-divinylbenzene as observed by GLC. However, precipitation due to agglomeration was observed at 25°C at 100% conversion.The high purity 1,3-bis(1-lithio-3-methylpentyl)benzene initiator, 2, is effective for the polymerization of 1,3-butadiene and allows the synthesis of polybutadienes with predictable molecular weights and narrow molecular weight distributions. Depending on the polymerization solvent, polybutadienes with microstructures ranging from 9 to 13% 1,2-vinyl content were observed by 1H NMR analysis and FTIR spectroscopy. However, the presence of diethylzinc retards the rate of polymerization of 1,3-butadiene, without any change in polymer microstructure. Triethylamine enhances the rate of 1,2-enchainment without significant reduction in the 1,4-enchainment of polybutadiene.

Zusätzliches Material: 8 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210350308

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8

Digitale Medien

Synthesis of highly isotactic (mm 〉 0.70) polyacrylonitrile by anionic polymerization using diethylberyllium as a main initiator (1994)

Nakano, Yasuhiro ; Hisatani, Kunio ; Kamide, Kenji

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 35 (1994), S. 207-213

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ISSN: 0959-8103

Schlagwort(e): stereospecific polymerization ; polyacrylonitrile ; tacticity ; diethylberyllium ; additive ; anionic polymerization ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: An attempt was made to synthesize steroregular polyacrylonitrile (PAN) with a high triad isotacticity (i.e. the content of mm (m, meso)) exceeding 0.70 by the anionic polymerization method. In the stereospecific polymerization of acrylonitrile (AN) initiated by diethylberyllium (Et2Be) in xylene at 130°C, the (mm) content as well as the viscosity-average molecular weight (MÞv) of PAN increased by addition of diisobutylaluminum hydride (i-C4H9)2AlH) as an additive to the polymerization system. Maximum (mm) content, attained in the molar ratio region of (i-C4H9)2AlH/Et2Be 〉 1.0, was about 0.73. The stereospecific polymerization of AN was also initiated using a mixture of Et2Be and di-n-hexylamagnesium ((Et2Be/(n-C6H13)2 Mg system), where both Et2Be and (n-C6H13)2 Mg can induce the stereospecific polymerization of AN at 130°C. The (mm) content of the PAN sample prepared using the Et2Be/(n-C6H13)2 Mg system ((mm) = 0.64) was higher than that of PAN samples synthesized using Et2Be alone ((mm) = 0.56) and (n-C6H13)2Mg alone ((mm) = 0.51) under the same conditions except initiator. A significant difference in 13C chemical shifts of α-carbons between Et2Be (1.35 ppm) and (n-C6H13)2Mg (10.72 ppm) dissolved in hydrocarbon solvent at 110°C leads us to the conclusion that when Et2Be induces the stereospecific polymerization in the Et2Be/(n-C6H13)2Mg system as initiator, the main role of (n-C6H13)2Mg is considered to be the suppression of the association of Et2Be (active site) itself.

Zusätzliches Material: 4 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210350211

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9

Digitale Medien

The preparation, compatibility and structure of PEEK-PES blends (1994)

Ni, Zhuo

New York, NY : Wiley-Blackwell

Polymers for Advanced Technologies 5 (1994), S. 612-614

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ISSN: 1042-7147

Schlagwort(e): PEEK-PES blend ; Sulfurization ; Compatibility ; DSC ; IR ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau

Notizen: Blends of polyetheretherketone and polyethersulfone (PEEK-PES blends) were prepared either by mechanically mixing fine PEEK and PES powders or by mixing PEEK and PES solutions in H2SO4 (98%). Partially compatible blends were obtained in the latter method. The sulfurization of PEEK or PES in concentrated sulphuric acid did not occur provided that the experiment was performed within 30 min. The Tg of the PEEK component increased and that of PES component decreased with the increase of PES weight fraction; the melting exothermic peak of the PEEK component did not appear in the DSC curves of the quenched blends, suggesting that PES can effectively reduce the crystallization of PEEK component. The major absorbances of the bands were characterized by IR spectroscopy; the frequency difference between PEEK or PES and their blends were observed. A linear correlation of absorbance ratios with PEEK weight fraction was found.

Zusätzliches Material: 3 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pat.1994.220050927

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10

Digitale Medien

Anionic synthesis and characterization of ω-formyl-functionalized polystyrenesDedicated to Professor Maurice Morton to commemorate the establishment of the Maurice Morton Institute of Polymer Science at the University of Akron. (1994)

Quirk, Roderic P. ; Kuang, Jianxin

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 33 (1994), S. 181-186

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ISSN: 0959-8103

Schlagwort(e): anionic polymerization ; functionalization ; aldehyde functional group ; 4-morpholinecarboxaldehyde ; diphenylphosphonic chloride ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: ω-Formyl-functionalized polystyrenes can be synthesized in quantitative yield by reacting poly(styryl)lithium (Mn = 2 × 103-8 × 103 g/mol) in benzene with a 0.1-0.4 molar excess of 4-morpholinecarboxaldehyde followed by methanol termination and precipitation into methanol. Narrow molecular weight distribution ω-formyl-functionalized polystyrenes were characterized by hydroxylamine end-group titration, thin layer chromatography and both 1H and 13C NMR spectroscopy. The mechanism of the functionalization was studied by trapping the tetrahedral α-amino alkoxide intermediate with diphenylphosphinic chloride.

Zusätzliches Material: 7 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210330209

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11

Digitale Medien

Some light on the concept of unreactivity arising from active center association in anionic polymerizationsDedicated to Professor Maurice Morton to commemorate the establishment of the Maurice Morton Institute of Polymer Science at the University of Akron. (1994)

Young, R. N. ; Fetters, L. J. ; Huang, J. S. ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 33 (1994), S. 217-231

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ISSN: 0959-8103

Schlagwort(e): organolithium ; anionic polymerization ; propagation reaction orders ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: A long held assumption in hydrocarbon based anionic polymerization involving organolithiums is that the aggregated species are unreactive and thus serve only as reservoirs from which the active singlet species momentarily emerge to participate in the initiation or propagation events. This work demonstrates that contrary to the notion of aggregate dormancy such species can participate in monomer addition. The approach involved freeze-dried vitrified polystyryllithium which was found to be reactive toward butadiene and methanol vapors. The sub-glass transition state of the polystyryllithium eliminates the establishment of the aggregate: singlet equilibrium as a result of the inability of chains to undergo diffusion. Furthermore, it is shown that the lower bound gradient for the dependence of propagation rate on active center concentration, within experimental error, is about 1/5 for the majority of those diene systems where the active center concentration covers at least two decades. A computer evaluation of the propagation rate: active center data was done with the aim of testing and determining the equilibrium constants of these aggregated systems.

Zusätzliches Material: 13 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210330213

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12

Digitale Medien

Partial crystallisation in liquid polymer electrolytes based on co-polymers of ethylene oxide/propylene oxide (1994)

Cameron, G. Gordon ; Ingram, Malcolm D. ; Qureshi, M. Younus ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 33 (1994), S. 347-351

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ISSN: 0959-8103

Schlagwort(e): polymer electrolytes ; ethylene oxide/propylene oxide co-polymers ; DSC ; crystallisation ; nucleation ; melting ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: Solutions of lithium perchlorate in a low molecular weight ethylene oxide/propylene oxide (EO/PO) co-polymer were studied by differential scanning calorimetry. The pure co-polymer was found to crystallise partially, while addition of the salt impaired crystallisation first by slowing crystal growth then by slowing nucleation. At high salt concentrations (∼1·0 molal) no crystallisation occurred. The solvation of Li+-ions and the introduction of ‘transient crosslinking’ between cations and anions effectively suppresses the separation of the polymer into microregions of EO and PO. The crystallisation phenomena are relevant to the use of these copolymers as ‘model’ polymer electrolyte systems.

Zusätzliches Material: 5 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pi.1994.210330401

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