Analysis of the Styrene-Divinylester Copolymerization; Reaction Heats, Double Bonds Conversion and Average Sequence Lengths

AUAD, MARÍA L.; ARANGUREN, MIRTA I.; BORRAJO, JULIO

POLYMER

Elsevier

Lugar: NY; Año: 2000 vol. 41 p. 3317 - 3329

0032-3861

A simple model, based on the free radical copolymerization theory of Mayo and Lewis, is developed to predict reaction heats, calorimetric and molar conversions and average sequence lengths, during the crosslinking reaction between a monounsaturated monomer (M1) and a multiunsaturated comonomer (M2). The M2-double bonds are assumed to react independently with equal initial reactivities. The input variables of the model are the initial reactivity ratios (r10, r20) and their variation with the global molar conversion, the initial composition of the reactive mixture (f10) and the molar heat of formation of the different bonds formed during the copolymerization (DH11, DH22, DH12). The application of this model allows to calculate the overall molar and calorimetric double bond conversions (Pm and Pc), the heat developed during the reaction (DHT), the conversions corresponding to each type of unsaturations (Pc1, Pc2, Pm1, Pm2), and the average sequence lengths of the reacted bonds ÖkN11l and kN22lÜ: Published data of experimental comonomers conversions in the system styrene–divinylester (S– DVER) were satisfactorily reproduced by including a functionality of both reactivity ratios with the overall conversion. Finally, it was shown that the assumption implicitly made in most published kinetic studies from the differential scanning calorimetric (DSC) data, that Pc and Pm are equivalent, is not general and this feature must be investigated in order to perform correct kinetic calculations. q2000 Elsevier Science Ltd. All rights reserved. Keywords: Crosslinking copolymerization; Reactivity ratios; Divinylester resins