Solid-State Modification of PBT with Cyclic Acetalized Galactitol and d-Mannitol: Influence of Composition and Chemical Microstructure on Thermal Properties

Abstract

Two bicyclic carbohydrate-based diols, 2,3:4,5di-O-methylene-galactitol (Galx) or 2,4:3,5-di-O-methylene-Dmannitol (Manx), were introduced into the backbone of poly(butylene terephthalate) using the solid-state modification technique (SSM). The resulting copolyesters had a unique block-like chemical microstructure that endows them with superior thermal properties when compared with their random counterparts obtained by melt copolymerization. The materials prepared by SSM displayed higher melting points, crystallization temperatures, and crystallinity due to the presence of long PBT sequences in the copolyester. The glass-transition temperatures also increased upon incorporation of the bicyclic comonomers, this effect being more pronounced for Manx units. The melting points of these block-like copolyesters decreased after melting due to the occurrence of randomization, but they remained higher than those of copolyesters prepared from the melt. SSM was demonstrated to be a very suitable technique for the incorporation of rigid monomers into the amorphous phase of PBT, leading to bio-based non-random copolyesters with remarkable thermal properties.

Partially renewable copolyesters prepared from acetalized d‐glucitol by solid‐state modification of poly(butylene terephthalate)

“…Hence, using a relatively low SSM reaction temperature, even though this temperature was below the melting point of the Glux crystals, was an appropriate approach to obtain PBT/Glux‐based materials where a significant part of the comonomer units are incorporated into the copolyester backbone. Similar results were obtained for the SSM of PBT with other sugar diols, namely, Galx and Manx . However, not all attempts to modify PBT with a sugar‐based diol were successful.…”

“…Interestingly, the molecular weight build‐up took a significant longer time compared with the chain scission reaction. Consequently, the total reaction time for the preparation of Glux‐based copolyesters is significantly longer compared with the reaction times necessary to incorporate similar amounts of 2,3:4,5‐di‐ O ‐methylene‐galactitol (Galx) or 2,4:3,5‐di‐ O ‐methylene‐ d ‐mannitol (Manx) under comparable SSM reaction conditions . The peculiar differences in reaction times can be explained by the differences in the molecular orientation and the melting point of the comonomers.…”

“…In particular, attention has been given to the modification of PBT with sugar‐derived bicyclic diols, since these lead to copolyesters, partially based on renewable resources, exhibiting remarkable thermal properties. Besides the incorporation by transesterification of a macrodiol derived from IS, recently the diols 2,3:4,5‐di‐ O ‐methylene‐galactitol (Galx) and 2,4:3,5‐di‐ O ‐methylene‐ D ‐mannitol (Manx) have been incorporated into PBT by SSM . Unlike IS, which is a cyclic diether obtained by the dehydration of D ‐glucose, these two symmetric compounds are cyclic diacetals derived from d ‐galactose and d ‐mannose, respectively.…”

Toughened aromatic poly-(decylene terephthalate) copolyesters with two renewable eugenol-based components via a random copolymerization method

“…Furthermore, the mechanical performance of synthesized polyesters from these renewable resources is far from ideal compared to DMT-based materials. 40,41 According to previously published reports from our group, 12 a methoxy group on the phenyl ring in the renewable eugenol-based monomers M1 and M2 reduces the structural symmetry of the entire system. strength and toughness) compared to conventional petroleum-based PET or PBT.…”

Modification of poly(ethylene 2,5-furandicarboxylate) with 1,4-cyclohexanedimethylene: Influence of composition on mechanical and barrier properties

“…Unfortunately, its T g was decreased to only M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT toughness of aliphatic polyesters. For example, the cyclic diol, 2,3:4,5-di-O-methylene-galactitol (Galx) and 2,4:3,5-di-O-methylene-D-mannitol (Manx) have been employed to improve the polyesters chain stiff so as to enhance their T g and mechanical properties [33][34][35][36]. The bio-based isosorbide has also been used as the monomers to modify polyesters [37][38].…”