Methyl lateral group

The effect of lateral methyl groups in the spacer on the phase behavior has been studied in several polybibenzoates [18,19] derived from poly(tetramethy]ene p,p bibenzoate), P4MB. The branched polymers display transition temperatures significantly lower than P4MB. Moreover, the substituents have a clear effect on the kind of mesophase formed. Thus, P4MB displays a smectic A mesophase, while the lateral methyl groups... 

Pour point Polyalkylene glycols with high proportions of propylene oxide, > 50%, exhibit very low pour points, down to -50 C. This results from the lateral methyl groups of the propylene oxide unit disrupting crystallisation. Table 2.9 shows a typical comparison. 

The Refs. [374, 375] are devoted to the synthesis of polyesterketones with lateral methyl groups. 

The copolymers of polyarylesterketones, containing lateral methyl groups, can be produced by low-temperature polycondensation of 2,2 -di-... 

Figure 21. Effect of lateral methyl groups on mesophase formation.

More recently a brief progress report by Rucker has appeared (757)], since it would seem to arise by a C —C cyclization involving a lateral methyl group of the polyisoprene chain. 

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