Dependence of Crystallization Behavior of Interacting Telechelic Poly(butylene succinate) Oligomer on Molecular Weight

Abstract

A large spherulite structure deteriorates the mechanical properties of crystalline polymers, and therefore various methods have been explored to increase primary nucleation density. Recently, chain-end modification has been proposed as an effective approach for regulating polymer crystal nucleation. However, the relevant nucleation mechanism still requires investigation. Therefore, in this work, 2-ureido-4[1H]-pyrimidinone (UPy) units, which can form stacks via quadruple hydrogen bonds with each other, are introduced as end groups for the preparation of interacting telechelic poly(butylene succinate) (PBS-UPy) oligomers with different molecular weights (Mns). The crystallization, especially the nucleation behavior of PBS-UPy, is studied in detail by comparing with the corresponding pre-polymer, the hydroxyl-terminal PBS (PBS-OH). The thermal properties of PBS-UPy exhibit similar Mn-dependent tendency to those of PBS-OH, but with weaker total crystallization rate. The spherulite growth rate is significantly reduced, whereas the primary nucleation density is highly promoted, after introducing UPy groups. Further investigation reveals that the mechanism of UPy stacks’ influence on nucleation ability changes from inhibition to promotion with respect to Mn. Even under an inhibition of nucleation ability, the final nucleation density is obviously increased because of a significant decline of the growth rate. In addition, the change in the impact of UPy stacks on nucleation ability is speculated to originate from the memory expression feasibility of ordered conformation in the melt during crystallization.

Crystallization, thermal and mechanical properties of stereocomplexed poly(lactide) with flexible PLLA/PCL multiblock copolymer

“…Therefore, the multi-block copolymers based on PLLA- b -PCL- b -PLLA exhibits poor crystallization ability. Similar phenomena have been reported by Chang et al 33 and Chen et al 34…”

Mechanical and Physical Changes in Bio-Polybutylene-Succinate Induced by UVC Ray Photodegradation

“…Melting temperature decreased in both PBS and PBS-CB during UVC exposure, showing a slight decrease in temperature stability, although values measured in PBS-CB were slightly higher than those in PBS at the same irradiation time. The melting temperature of PBS increases with the increase in molecular weight [42]. Therefore, the decrease in melting temperature values during irradiation suggests that the polymeric matrix undergoes a degradation effect during exposure to UVC rays with a consequent decrease in its molecular weight.…”

Promoting Co-Crystallization in Poly(butylene succinate) and Poly(butylene fumarate) Blends via End-Group Functionalization

“…The blend of UPy end-group functionalized poly( l -lactide) (PLLA-UPy) and poly( d -lactic acid) (PDLA-UPy) exhibits a marked enhancement of stereocomplex crystallization (a unique co-crystallization method) and the suppressed crystallization ability of homo-PLA, because the dimerization of UPy groups randomly connects the PLLA-UPy and PDLA-UPy chains, leading to a dramatic increase in compatibility and miscibility between different components [ 15 , 16 ]. Meanwhile, UPy has been considered for use as a linker for the supramolecular design of polymers, including PLA [ 17 ], poly(ethylene glycol) (PEG) [ 18 ], poly(ε-caprolactone) (PCL) [ 19 ], and poly(butylene succinate) [ 20 ], which could supply the foundation for manipulating co-crystallization behavior in crystalline/crystalline blends.…”