On influence of imide rings on the structure of polyesterimides
Polimery 1994, No 9, 514
The structural study of a series of polyesterimides (PEI) from derivatives of pyromellitic anhydride has been carried out by X-ray diffractometry and DSC. These copolymers were prepared by condensation of bis(Nchloroformylmethyl) pyromellitimide with polyoxyethylene glycols (PEOX) of various molecular weights. The increasein the molecular weight of PEOX units caused an increase in the crystallinity of PEIs studied. The differences between the degree of crystallinity and the weight fraction of polyglycol units in copolyimides prove that only some part of polyglycol in copolyimides can be retained within the crystalline structure.The dominating effect of poly(ethylene glycol) comonomer on the crystallinity, structure and thermal stability of these copolymers was demonstrated. The influence of imide rings on liquid crystal properties of esterimides was studied, too. Also in this case, it was noticed that imide ring did not favour an ordered structure. The parameters of the crystalline network in PEIs are identical to those of PEOX used in the synthesis of PEIs. The imideester groups not only do not introduce their own spatial structures, but they distort the order of glycol mers by the formation of the so-called excluded volumes with limited mobility which are, therefore, not able to participate in the formation of crystalline regions.
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