Crystallization and shear-induced formation of organogels in novel poly[(butylene succinate)-co -diolisobutyl]-[polyhedral oligomeric silsesquioxane] copolyesters

Abstract

A series of novel poly[(butylene succinate)-co-diolisobutyl]-[ polyhedral oligomeric silsesquioxane] (PBS-POSS) copolyestershave been synthesized for the first time directly from diacid and diols via melting polycondensation. Both PBS and POSS segments crystallized as revealed by X-ray diffraction, and the crystallization of PBS was found to be retarded by the incorporation of POSS into PBS chains based on differential scanning calorimetry and rheological results. Moreover, the copolyester containing 3 mol% POSS formed organogels in chloroform by the treatment of shear flow and was more thermally stable than the pristine sample, due to formation of a physically crosslinked network caused by the crystallization of POSS into crystals of larger sizes.

Polybutadiene/polyhedral oligomeric silsesquioxane nanohybrid: investigation of various reactants in polyesterification reaction

“…and Table , the values of T g and Δ H m are higher than those for the linear macromers. This phenomenon may be attributed to heterogeneous nucleation effect of the POSS molecules or POSS/polymer nanohybrids dispersed uniformly in the polymer matrix …”

Polyisobutylene containing organic/inorganic hybrid block copolymers and their crystalline behavior

“…We observed an opposite trend of crystallinity in copolymer composite with varying POSS content, where raftlike crystalline structure is formed due to aggregation of more and more POSS particles . Spherical POSS units in some copolymer composites are found to form a crystalline domain even though; they are linked to polymer backbone by covalent bond, where the crystallizable units are randomly distributed and separated by other monomeric units . But in blocky architecture POSS blocks are likely to be amorphous.…”

“…We did not find any microphase separated structures for the synthesized block copolymers (Supporting Information Fig. S2), but they formed somewhat unusual shaped particle of different size in the range of 10 to 15 nm because of aggregation and crystallization of POSS nanosphere, although TEM images does not show microphase separated PMAPOSS segment. Size and shape of the microstructure was found not to change significantly with increasing content of POSS segment into the block copolymers.…”

“…48 Spherical POSS units in some copolymer composites are found to form a crystalline domain even though; they are linked to polymer backbone by covalent bond, where the crystallizable units are randomly distributed and separated by other monomeric units. 49 But in blocky architecture POSS blocks are likely to be amorphous.…”