Poly random copolymer blend with PMMA

Elsewhere [182], the morphology of polystyrene/poly(methyl methacrylate) blends with methyl methacrylate/POSS random copolymers (containing 5.5% m/m—PMMA-POSS5 8.0% m/m - PMMA-POSSIO and 10.7% m/m—... 

EOS models were derived for polymer blends that gave the first evidence of the severe pressure - dependence of the phase behaviour of such blends [41,42], First, experimental data under pressure were presented for the mixture of poly(ethyl acetate) and polyfvinylidene fluoride) [9], and later for in several other systems [27,43,44,45], However, the direction of the shift in cloud-point temperature with pressure proved to be system-dependent. In addition, the phase behaviour of mixtures containing random copolymers strongly depends on the exact chemical composition of both copolymers. In the production of reactor blends or copolymers a small variation of the reactor feed or process variables, such as temperature and pressure, may lead to demixing of the copolymer solution (or the blend) in the reactor. Fig. 9.7-1 shows some data collected in a laser-light-scattering autoclave on the blend PMMA/SAN [46],... 

Besides the overall composition of blends and random copolymers, valuable information can be obtained in the case of block copolymers. If a block copolymer contains a homopolymer fraction, a shoulder or second maximum in the MMD curve can be obtained that should have a different chemical composition. Figure 9 shows the MMD of a block copolymer of methyl methacrylate and decyl methacrylate, in which a second lower molar mass maximum can be identified as poly(decyl methacrylate) (PDMA) by dual detection [37]. The increase in the PDMA content with molar mass in the main fraction is reasonable and corresponds well with what is expected from the synthesis. It is worth noticing that this type of information can only be obtained by the D-RI detector combination, because both PDMA and PMMA have a similar low response in UV. 

Random copolymer addition to binary blends involving copolymers with structural units equal or similar to the blend components or with specific interacting groups capable of non-reactive interaction with one of both the blend components comprises another ternary polymer addition approach. An early example involved EPR (ethylene-propylene rubber) addition to HDPE/PP blends, where synergistic impact strength was observed. In some cases, the random copolymers have been compared to block copolymers comprised of the same units. The compatibihzation of LLDPE/PMMA and LLDPE/poly(MMA-co-4-vinyl pyri-dine(4VP)) blends with poly(ethylene-co-methacrylic acid) (EMAA) addition were compared [47]. Modest improvements in LLDPE/PMMA dispersion and strength were observed. The specific acid-base interaction allowed for much larger improvements with EMAA addition to LLDPE/PMMA-CO-4VP blends. 

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