Styrene peroxide

Solomon (3, h, 5.) reported that various clays inhibited or retarded free radical reactions such as thermal and peroxide-initiated polymerization of methyl methacrylate and styrene, peroxide-initiated styrene-unsaturated polyester copolymerization, as well as sulfur vulcanization of styrene-butadiene copolymer rubber. The proposed mechanism for inhibition involved deactivation of free radicals by a one-electron transfer to octahedral aluminum sites on the clay, resulting in a conversion of the free radical, i.e. catalyst radical or chain radical, to a cation which is inactive in these radical initiated and/or propagated reactions. 

Poly(peroxyisobutyrolactone). 1536 Poly (styrene peroxide), 2957 Poly (vinyl acetate peroxide), 1539 Styrene, Oxygen, 2945... 

One report has appeared on the decomposition of poly (styrene peroxide). ... 

For example, transition metal salicylates (Ni(II), Co(II), Mn(II) and Fe(III) salicylates) accelerate decomposition of poly(styrene peroxides) [1203]. 

Figure 6.22 compares the performance of the one-step and two-step reactive compatibilization processes. The one-step process corresponds to screw profile B3. In order to make the comparison meaningful, the two-step process uses the same screw profile as the one-step process. Moreover, the composition of the free radical grafting system is the same for both processes, namely, PP/MA/styrene/peroxide = 100/1.5/1.6/0.3 by weight. In this way, the amount of grafted MA onto PP is the same (0.5 phr) in both processes. Five different PP/PA6 (80/20) blends are made using the two-step process in which the PP phase contains 0,20,40,60 or 80wt.% PP-g-MA. The rest of the PP phase is composed of an inert PP (the inert PP used has better mechanical properties than that used for the experiments in Fig. 6.21). The same number of PP/PA6 (80/20) blends is obtained using the one-step process. In order for the blends obtained with the one-step process to have the same compositions (the inert PP, PP-g-MA and PA6) as those obtained with the two-step proeess, the feed rates at the first and second hoppers for different chemicals are adjusted accordingly. Results show that the compatibilization perfonnance of the one-step process is quite similar to that of the two-step process. For example, none of the blends...

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