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  • 1985-1989  (2)
  • 1955-1959  (29)
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  • 1
    Electronic Resource
    Electronic Resource
    Polymers and group interaction. IV. Hofmann reaction on polyvinylamides (1957)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 23 (1957), S. 915-930 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Hofmann degradation reaction has been applied to polyvinylamides in order to obtain aminocarboxylic polyampholytes. When the reaction is effected in aqueous solution, interactions occur between isocyanate and neighboring chloroimide ions, with the formation of butyrolactam ring units incorporated in the polymeric chain. The structural composition of the polymers has been determined on the basis of the following analytical results: total and volatile nitrogen, total and ionic chlorine, and conductometric and potentiometric titrations. In the case of polymethacrylamide the end product consists of about 57% lactam rings, 28% free amine chlorohydrate, and 8% methacrylic acid units, while about 5 to 6% amide groups remain unreacted. In the case of polyacrylamide the degree of conversion is usually lower; this difference in behavior has been interpreted as being due to the high substitution in the methacrylic derivative. When the reaction is effected in water-methanol (50/50) solution, any ring formation is absent; contrariwise, the isocyanate functions are transformed into carbamate units. In alcoholic medium it is possible to obtain polymers containing about 50% carbamic functions, as well as small amounts of free amines (3%); the residual percentages are acid or unreacted amide groups. On alkaline hydrolysis of these carbamic functions, free amine functions are produced; however, the rate of hydrolysis is very low if compared to that of usual amides. This effect has been attributed to the nitrogen substitution in the carbamate units and to the electrostatic repulsion effect of the carboxylate functions toward the hydroxyl ion. For verification, the alkaline hydrolysis rate constants of N-isopropyl methylcarbamate have been compared with those of methylcarbamate; they were found to be about ten times slower. Moreover, the corresponding activation energy of alkaline hydrolysis was 18.7 kcal./mole instead of 14.1 in the case of the unsubstituted methylcarbamate. The products obtained by Hofmann degradation on polymethacrylamide have been compared to those obtained by Lossen rearrangement reaction on polymethacroyl chloride; the structural units were found to be identical in both cases.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1957.1202310435
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  • 2
    Electronic Resource
    Electronic Resource
    Kinetics of polymerization of vinylene carbonate (1958)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 29 (1958), S. 257-274 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of polymerization of vinylene carbonate have been studied as a function of the concentration of initiator, the concentration of monomer, and the temperature. In acetone solution, the order of reaction with respect to the concentration of initiator is equal to 0.5, independent of the monomer concentration ((M) = 4.15 and 14.7 mole/l.); moreover any thermal polymerization is absent at 70°C. Contrary in ethylbenzoate ((M) = 3.41 mole/l. at 77°C.) the apparent order with respect to the initiator is 0.77; in agreement with the results of Scanlan in the case of vinylacetate. This behavior is interpreted on the basis of an efficiency factor q, corresponding to the fraction of solvent radicals able to reinitiate a growing chain. In ethylbenzoate solution this factor q is equal to 0.45 and 0.80 for vinylene carbonate and vinylacetate, respectively. With respect to the monomer concentration, the order of the reaction is 1 in the presence of ethylene carbonate as solvent over the total range of concentrations. The transfer constant with this solvent is negligible because it results from molecular weight determinations at constant initiator concentration. In acetone and in benzene the apparent order of reaction is 1, only in dilute solutions; in concentrated solutions small amounts of solvent cause a strong decrease of the rates of reactions. This behavior has been interpreted on the basis of a general kinetic scheme, in which the cross-termination rate constant Φ and the chain transfer constant with the solvent are the predominant factors. In ethylbenzoate the reaction is characterized by a partial degradative chain transfer. The overall activation energy of the polymerization of vinylene carbonate is 22.2 kcal./mole and the coefficient A of the Arrhenius equation is equal to 3.0 × 10-9.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1958.1202911919
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  • 3
    Electronic Resource
    Electronic Resource
    Hydrolysis of polyacrylamide and acrylic acid-acrylamide copolymers (1959)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 40 (1959), S. 217-226 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The hydrolysis of polyamides has been studied in buffered acid solution at 110°C. at an amide concentration of 0.05 M. In the case of polyacrylamide, the reaction was carried out in acetate buffer at different values of the ratio r (acetic acid/sodium acetate). The initial velocity is low and is proportional to the concentration of acetic acid; the rate constant is equal to 2.6 × 10-6; this reaction accelerates, however, as soon as the degree of conversion exceeds 3 to 5%. In the case of copolymers of acrylamide and acrylic acid (r1 = 1.38 and r2 = 0.36, respectively), the reaction proceeds in two distinct steps, of which the first is about 50 to 100 times more rapid than the second. By carrying out the reaction with copolymers of different composition (70, 74.5, 85, and 88 mole-% acid) and varying the degree of neutralization for each (r = 2, 10, and 49), it is shown that the rapid first step results from the interaction between an amide group and an undissociated, directly neighboring acid group, which moreover must be present in a welldetermined stereochemical position. The stereospecificity of the kinetics of this reaction was demonstrated by the difference in the behavior of two copolymers of the same over-all composition but different internal structure. The slow second step of the hydrolysis of the copolymer corresponds sensibly to the action on polyacrylamide by external acid; the retardation is a consequence of the fact that the requirements of vicinality and stereospecificity are not satisfied for the residual for the amide groups.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1959.1204013616
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  • 4
    Electronic Resource
    Electronic Resource
    Polymers and group interaction. VIII. Synthesis of a styrene-amino acid copolymer (1959)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 40 (1959), S. 227-236 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A copolymer of styrene-maleimide has been obtained by reaction of a styrene-maleic anhydride copolymer with ammonia under pressure in acetone solution at 70-90°C. The co(styrene-maleimide) polymer was submitted to Hofmann degradation reaction in aqueous medium and in water-tert-butyl alcohol solution. In aqueous solution the amine formation is accompanied by partial lactam formation resulting from interaction between acid and amine groups. In water-tert-butanol this cyclization reaction did not take place, since there was formation of tert-butyl carbamates. These carbamate groups may be hydrolyzed in acetic acid solution in the presence of hydrochloric acid, and afford free amino groups. In both media, appreciable hydrolysis proceeds simultaneously with the Hofmann reaction, so that the number of carboxyl groups exceeds by far the number of amino groups (75 vs. 20-25%).
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1959.1204013617
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  • 5
    Electronic Resource
    Electronic Resource
    Polymers and group interaction. V. Reaction of diazomethane on polymethacroyl chloride (1957)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 24 (1957), S. 261-274 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In order to follow the course of the Arndt-Eistert reaction on a polymeric system, polymethacryol chloride has been reacted with diazomethane in dioxane solution using different molar ratios of diazomethane/acid chloride at different temperatures. The structure of the reaction products has been determined by chemical methods and by infrared spectrometry. The contents of acid chloride and diazoketone units have been evaluated from chlorine and nitrogen analyses, respectively; conductometric and potentiometric titrations allow determination of the percentages of ketene and pseudo-acid groups. From these data it is concluded that the first reaction products of diazomethane on an acid chloride unit are diazoketone groups, as expected; however, the interaction of these primary groups with the neighboring acid chloride units yields principally β-ketocycloketene functions. The presence of these groups and their content have been confirmed by a decarboxylation reaction effected by hydrolysis in acidic medium, during which carbon dioxide is evolved, while the acid content decreases and cyclic ketones are formed. Their presence has also been confirmed by oxidation with dilute nitric acid, which transforms the polymer into polymethacrylic acid. These results of decarboxylation and of oxidation are unreconcilable with the formation of the higher homolog of polymethacrylic acid, the polyisopropenylacetic acid, which would be the normal chainlengthening reaction product of the Arndt-Eistert reaction. Infrared spectrometry shows, in the triple bond region, absorption bands at 4.65 and 4.73 μ, and, in the double bond region, bands at 5.55, 5.70, 5.80, and 6.10 μ. By comparison with the data in the literature, and especially with the spectrum of the glutaric bisdiazoketone, these different bands have been assigned and their relative intensities interpreted. The spectrometric results confirm the presence of diazoketone and β-ketoketene groups; moreover, they show relatively low amounts of cyclopentanone rings and of ester functions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1957.1202410607
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  • 6
    Electronic Resource
    Electronic Resource
    Polymers and group interactions. VI. Intramolecular acylations on copolymers of styrene and acrylic acid derivatives, a route to poly-2,4-methylenetetralone (1958)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 27 (1958), S. 441-457 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The intramolecular cyclization of 50/50 styrene-acrylic acid (or derivatives) copolymers has been investigated; the purpose of this work was the synthesis of a high molecular weight poly-2,4-methylenetetralone. The cyclization of styrene-(meth)acroyl chloride copolymers in the presence of aluminum chloride gives under rather mild experimental conditions high yields of tetralone units, together with some tricyclic units of the hexahydrophenalenedione type. This cyclization reaction was, however, always concomitant with a strong degradation of the polymeric chains: it results from the formation of a carbonium ion on the main chain through a secondary decarbonylation reaction, as shown by chemical determination. The cyclodehydration of a styrene(meth)acrylic acid copolymer was carried out with good yields in an acetylating mixture, in the presence of various catalysts such as zinc chloride, polyphosphoric acid, or phosphorus oxychloride. The cyclization to tetralone units is concomitant with the formation of anhydride groups, and in the case of acrylic acid, of enol-ester groups: the alkaline hydrolysis of the products yields terpolymers of styrene, acrylic acid, and methylenetetralone. Moreover, using polyphosphoric acid or phosphorus oxychloride, the intrinsic viscosity of the cyclized copolymers remains important, even at rather high degree of conversion. The cyclization of styrene-methyl(meth) acrylate copolymers in heterogeneous medium, in polyphosphoric acid, was also carried out; the degradation process is very small. The methacrylic ester copolymers undergo, however, an important gelification, while the acrylic copolymers yield, besides the usual tetralone units, some tetracyclic units of the tetrahydro-3,4-benzophenanthrene type.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1958.1202711534
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  • 7
    Electronic Resource
    Electronic Resource
    Ionic grafting (1958)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 33 (1958), S. 227-234 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cationic polymerization of isobutene has been carried out in carbon disulfide solution in the presence of AlBr3 and chloromethylpolystyrene at -60°C. in order to obtain graft copolymers. The separation of the graft copolymers from the reaction mixtures in benzene solution was based on a standardized precipitation technique involving use successively of butanone and methanol as precipitating agents. By this method, fractions with an intermediate solubility have been isolated and purified twice. The differences of solubility of their products are discussed. Their isobutene content and intrinsic viscosities have been determined. The degree of grafting of these products is usually low (5-18%).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1958.1203312622
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  • 8
    Electronic Resource
    Electronic Resource
    Polymer and group interactions. VII. Lactonization of polyethyl α-chloroacrylatePresented in part at the International Symposium on High Polymers, Prague, September 9-15, 1957. (1959)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 35 (1959), S. 519-528 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyethyl α-chloroacrylate (PCA) has been condensed in the presence of aluminum chloride and aromatic hydrocarbons; the molar ratio AICl3/PCA was usually higher than unity. Although the halogen content decreases with a higher degree of conversion, no aromatic hydrocarbons are incorporated into the polymer. The reaction proceeds through a nucleophilic substitution mechanism with intramolecular lactonization; the polymer composition has been calculated from the halogen content and the conductometric titration of free acid and lactone rings after opening. The degrees of polymerization of the reaction products were determined by the osmotic method in order to evaluate the importance of the chain degradation during the condensation. In spite of the high condensation temperature and the high degree of conversion, the degrees of polymerization are about 40-50% of that of the initial PCA. While the limited viscosity numbers vary only slightly, the Huggins-Schulz k′ constant values decrease regularly with an increasing degree of lactonization.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1959.1203512918
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  • 9
    Electronic Resource
    Electronic Resource
    Kinetics of polymerization of N-vinylurethane (1959)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 37 (1959), S. 445-454 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of polymerization of N-vinylurethane has heen studied hy rate determination as well as by determination of molecular weights. The order of reaction with respect to the initiator (azoisobutyronitrile) is equal to 0.5 both in bulk and in acetone solution (2.95 moles/1.); moreover, any thermal polymerization is negligible under these experimental conditions. The number-average molecular weights of the polymers were determined by the osmotic method; the chain transfer with monomer at 60°C. is equal to 2.5 × 10-5. It can be shown that the efficiency of the initiator is at least equal to 0.59, and that the chain termination proceeds principally through disproportionation. The ratio kp2/kt is about 0.18, which is practically equivalent to that of vinyl acetate. By polymerization in solution and by determination of the corresponding molecular weight, chain transfer constants at 60°C. were evaluated for acetone (Cs = 8.5 × 10-4) and for benzene (Cs = 1.25 × 10-4); these values were confirmed by rate measurements. The rate dependence on monomer concentration is different in each case. In dilute solution, the order is 1 in benzene, while it is nearly 1.5 in acetone. In concentrated solutions, the apparent order increases gradually, owing to the importance of both chain transfer and cross-termination reactions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1959.1203713215
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  • 10
    Electronic Resource
    Electronic Resource
    Hydrolysis of methacrylic acid-methyl methacrylate copolymers (1959)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 40 (1959), S. 203-216 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Several copolymers of methacrylic acid and methyl methacrylate have been prepared with acid contents of 28.8, 50, 60, 66, 72, 83, and 86.5%; they have been hydrolyzed in acidic medium at 110°C. at different neutralization ratios r = [HA]/[A-]. Except for those with the highest acid content, all the copolymers show a two-step hydrolysis, in which the second step is about 1/6-1/7 slower than the first. The order of reaction is one with respect to the acid concentration and one with respect to the ester concentration. On the basis of general catalysis, as suggested by Brønsted, two hydrolysis rate constants kHA and kA- may be evaluated; they correspond to the hydrolysis catalyzed by undissociated carboxyl groups and by carboxylate groups. At 110°C., kHA and kA- are equal, respectively, to 1.5 × 105 and 1.0 × 105; consequently, the rates of hydrolysis are practically insensitive to the ratios of neutralization r, except when r = 3. From comparison of the behavior of these acid-ester copolymers with that of a methyl methacrylic-N-vinylpyrrolidone copolymer in the presence of an acid-buffered solution (acetic tic or polymethacrylic acid), it becomes evident that the hydrolysis reaction consists essentially of a functional interaction between an ester function on one side, and a carboxyl and/or a carboxylate directly neighboring function on the other side. Moreover, on the basis of structural probability calculations, the immediate vicinality effect is insufficient to explain the rates and limited degree of conversion of the hydrolysis reaction. For the copolymers with high acid content (C72, C83, and C86.6) at r = 3, the rate of reaction is triple that at the other r-values. This strong increase of the reaction velocity is, as expected, characterized by an appreciable decrease in the energy of activation (16 kcal. instead of 23 kcal.) This behavior is attributed to a “concerted” mechanism which should be particularly enhanced at r = 3. It has been demonstrated that the stereochemical composition of these copolymers exerts a deep influence on the rate of hydrolysis as well as on the degree of conversion in these reactions.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1959.1204013615
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