An attempt is made to prove the possibility of synthesizing copolymers of JV-vinylpyrrolidone (VP) and maleic anhydride (MA) with a kinetically regulated structure of the macromolecule. The influence of the charge-transfer complex (CTC), formed from VP and MA, on the dominating tendency toward alternating copolymerization of the two comonomers is studied. The process is carried out on the following model of interaction: a mixture of VP and MA (molar ratio 1:1) is added at a fixed value of mass flow to the reaction system where VP homopolymerization takes place. The copolymerization is studied under adiabatic and isothermal conditions at different mass flow values. The correlation between the parameters of the adiabatic process and the composition and molecular weight of the copolymers obtained in isothermal conditions at one and the same mass flow value is found. It was found that the decrease of the mixture mass flow to a certain value does not affect the copolymers composition and the dynamic of the temperature change in the adiabatic regime. The decrease of mass flow below that threshold leads to increasing the VP content in the product and to enhancing the rate of temperature increase in the adiabatic regime. The analysis of these data shows that it is quite possible to maintain a definite content of MA in the system, at which the dominating tendency toward alternation is disturbed. The results allow us to clarify the role of CTC in the VP/MA copolymerization process and to give a positive answer to the question: Is it possible to synthesize copolymers with a kinetically regulated structure of the macromolecule?
SYNOPSISThe aim of the present study is to clarify some problems concerning the synthesis of additional quantities of ethyl-2-cyanoacrylate monomer ( ECA) utilizing the waste residue (WR) from the large-scale depolymerization of ECA oligomers. The composition of WR was established by GPC and IR spectroscopy. WR was found to consist mostly of diethyl dicyanoglutarate (DEDCG) and low molecular weight products of its condensation with paraformaldehyde (pFA) . The DEDCG-pFA interaction was studied as a model, and the influence of DEDCG conversion on the average degree of polymerization (X, and Fw) of the oligomers formed was also followed. On this basis, it was found that oligomer formation in condensation of WR with pFA is consistent with a stepgrowth mechanism, the polymer chain length being determined by steric hindrance and destructive reactions. wherein R = alkyl and B-= organic or inorganic base.
This study deals with the copolymerization of trioxane (TO) and 1‐chloro‐2, 3‐epoxypropane (epichlorohydrin, ECH) catalyzed by EtB⊖F3 A⊕lEt2 in toluene. The rate of exhaustion of monomers during copolymerization was measured by gas chromatography. It was established that no homopolymers were formed. The copolymers obtained show a high alkali resistance, indicating a statistical distribution of the ECH in the polymer chain. During the first stages of the copolymerization the ECH is exhausted almost instantaneously, whereas TO is gradually exhausted, finally reaching a certain equilibrium depending both on the quantity of the initial ECH and on the temperature at which the process was carried out. Copolymerization is inhibited at increased ECH levels, and only homopolymerization occurs at a certain critical concentration of ECH.
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