Copolymerization Kinetics, Thermochemistry and Rheology

A study of the inhibitors for UPRs was published by Matynia et aL [187]. Efficient inhibiting systems consist of a quinone (benzoquinone, anthraqui-none, 1,4-naphthoquinone, or 9,10-phenanthrenquinone) and a diphenol derivative [ferf-butylhydroquinone or 4-(ferf-butyl)pyrocatechol[. 

The DSC method is commonly used for the study of the cming kinetics of a UPR. The kinetic analysis of the crosslinking process initiated with MEKP was performed by means of an empirical and theoretical model based on the concept of free-radical polymerization [190]. A calculation algorithm based on the downhill simplex method and the Rimge-Kutta procedure was proposed. The non-isothermal DSC analyses allowed to obtain the concentration of the initiator and the radicals as a function of cure temperature at 

Wave number [cm-i] Tentative assignment Component Cme evolution 

Also in that research, it was proved that the increase in the initiator concentration raised the polymerization rate, but did not affect the final conversion. On the contrary, the increase in styrene concentration reduced the 

UPRs based on a mixture of maleic anhydride, phthalic anhydride and adipic acid in a molar ration of 1 2 2 were prepared in the presence of the polyesterification catalysts, i.e. lead dioxide, p-toluenesulfonic acid monohydrate and zinc acetate dihydrate, and next crossHnked with styrene by using MEKP as the initiator and cobalt naphthenate (CoNp) as the promoter [197]. Most often, the catalysts used in the polyesterification process cannot be easily separated from the polyester, thus the effect of the residual catalysts on the curing process and color of the cured polyester resin should be taken into account. It was shown that the residual catalyst could affect the curing reaction even in a small amount (Table 28), increasing the activation energy a, frequency factor ko and the reaction order x. 

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