摘要:

AbstractThe mechanism of the formation of soluble and network polymers during the process of anionic polymerization of oligoesteracrylates (OEA) was investigated.It was shown that the network polymer was built from charged branching macromolecules. The anionic polimerization of OEA establishes the equilibrium in the process of electron distribution between functional groups of OEA and equilibrium between soluble and network polymers and residual OEA. Both types of equilibria are determined by the temperature and the ratio of concentration of OEA and catalyst. The equilibrium in the system of network and soluble polymers and residual OEA is established both by the interaction of catalyst with OEA and with “dead” network polymer which may be “vitalized” in t

ISSN:0360-8905    

DOI:10.1002/polc.5070420103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractAqueous hydrogen peroxide thermally decomposes into two hydroxyl radicals which readily initiate a radical polymerization process. Ethylenic monomers and aqueous hydrogen peroxide are generally nonmiscible liquids in all proportions, and the addition of an alcohol to the reaction medium greatly modifies the thermodynamic conditions. Liquid and solid products are obtained having 1.7 to 1.9 hydroxyl groups per macromolecule and their average molecular weights vary between 700 to 100,000. For diene monomer polymerization, low molecular weight oligomers as well as higher molecular weight polymers are obtained. Structures of the diene polymers obtained show that aqueous hydrogen peroxide‐initiated polymerization proceeds by a 1, 2 addition for their initiation step and a 1, 4 addition for propagatio

ISSN:0360-8905    

DOI:10.1002/polc.5070420104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractAn investigation was made of the kinetics of polymerization initiated with carboxylic acids of different acidity, namely, caprylic,p‐fluorobenzoic, ando‐chlorobenzoic acids at 220–280°C and also with capryllactam hydrochloride for comparison. The polymerization proceeds without an induction period, is little dependent on the acidity of the initiator, and can be expressed in terms of a simple kinetic equation:‐dL/dt = k I0aL. If carboxylic acids are used for initiation, the exponentais 0.82, the pre‐exponential factor and the activation energy of polymerization is 1.85 × 1012and 30 kcal/mol respectively. In the discussion, the polymerization of capryllactam is compared with the polymerizations of caprolactam and

ISSN:0360-8905    

DOI:10.1002/polc.5070420105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractA method is presented to recover the polymer formed in the free radical bulk polymerization of ethylene as a powder rather than as a melt. The paper mentions several advantages of this new approach, which has been used in a study on the production of medium and high density polyethylene with the aid of radical initiators at temperatures below the melting point of polyethylene (suspension bulk polymerization). The method of preparing products with a very high stiffness comparable to that of homopolymers made by the Ziegler process is, in principle, also applicable at polymerization termperatures above the melting point of polyethylene, provided (meth) acrylamide is employed as a comonomer.

ISSN:0360-8905    

DOI:10.1002/polc.5070420106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractPolyhydantoins have been prepared by a polyaddition cyclocondensation reaction of glutamic acid with aromatic diisocyanates in apolar medium (diphenyl ether).The reaction takes place in two steps: in the first with the formation of polyamide‐ureas and thermal cyclation of them in a second step. These polyhydantoins are soluble in polar solvents and show good thermal stabilit

ISSN:0360-8905    

DOI:10.1002/polc.5070420107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractQuaternary ammonium salts of α‐pyrrolidone, α‐piperidone and ε‐caprolactam, preparedextra situ, were used as catalysts in anionic polymerization of these lactams. Pyrrolidone and piperidone salts gave the corresponding lactam polymers of increased molecular weight, with an improved yield, as compared to those obtained using classical alkaline catalysts (a true high polymer of piperidone with a reduced viscosity of 4.58 was obtained for the first time). The caprolactam polymerization succeeded only at comparatively low temperatures (∼ 100°C).The high activity of these catalysts permitted us to prepare high polymers, using slow initiators or initiators of inferior activity. The influences of coexisting functional groups extraneous to the polymerization, namely water, are demonstrated.The polymerization data indicate that the dimension of catalyst cation plays an important part in molecular growth in the heterogeneous reaction phase and provide some arguments in favor of ou

ISSN:0360-8905    

DOI:10.1002/polc.5070420108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractDespite the considerable interest displayed by industry in latex polymers with functional groups, the study of the process of producing such latexes by the method of emulsion polymerization has just started. It should be expected that the introduction of functional groups into the interphase layer will entail a change in the course of the colloid and polymerization processes in the reaction system. In this work, the authors studied precisely this aspect of the process of emulsion copolymerization. Correlation between the polarity of a monomer (or monomer composition) on the one hand, and the kinetics of polymerization and adsorption of the emulsifier, on the other, has been shown in the case of alkyl acrylates and their copolymerization with functional monomers differing in their solubility in water. It has also been shown that localization in the interphase layer of functional groups capable of interaction, for instance, owing to the formation of hydrogen bonds, sharply intensifies the effect of these groups on the mechanical and thermomechanical properties of a polymer obtained through emulsion polymerization. The same fact leads to localization of crossing processes in interglobular regions in a latex polymer.

ISSN:0360-8905    

DOI:10.1002/polc.5070420109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractThe polymerization of monomers in a thin layer in air is very sensitive to the variations in the initial composition of the polymerized system. A study of the effect of initial mixture composition on the regularities of the polymerization kinetics elucidates the specific features of the process, and thereby facilitates its control. This paper reports the effect of active fillers (aerosil) on the kinetics of bulk polymerization of aminoalkylmethacrylates in a layer of specific thickness and in volume. The rheological parameters of the polymerized system were measured. Such investigations revealing the kinetics of the variations in the rheological parameters during polymerization are of considerable significance for establishing a relationship between both processes. Besides, they have practical value for the production technology of polymer coatings by direct polymerization of monomers. The data obtained in this work clearly demonstrate the effect of coagulation structure developed by adding an active filler into system to be polymerized on the polymerization process.

ISSN:0360-8905    

DOI:10.1002/polc.5070420110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractIn the anionic polymerization of ε‐caprolactam, approximately 0.5–1 keto group is formed per one activator molecule very quickly at 250–280°C. The concentration of the keto groups in the polymerizate depends on the initial concentrations of the catalytic components, the temperature, and the polymerization time. At a low effective basicity, the majority of keto groups originates during the first minutes, whereas at higher basicities most of the keto groups are formed in the later stages of the process. In polymers prepared in the presence of sodium caprolactam and N‐benzoylcaprolactam there occurs transitional branching and the primary branched chains become linearized during extende

ISSN:0360-8905    

DOI:10.1002/polc.5070420111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractN, 2‐Disubstituted andN, 2, 2‐trisubstituted amides of 3‐oxocarboxylic acids represent the model moieties incorporated in the anionic polymers of lactams and α‐substituted lactams as a result of side reactions of the catalyst components. Aminoketones traced in polymers prepared by means of 3‐oxoamides as activators indicate the prefered mechanism of regeneration of the growths centers during polymerization. The presence of ketone units in anionic α‐methyl‐ε‐caprolactam polymers indicates condensation at the α‐carbon atom similarly as in the case of nonsubstituted

ISSN:0360-8905    

DOI:10.1002/polc.5070420112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY