Morphology, Surface Structure, and Elastic Properties of PBT-Based Copolyesters with PEO-b-PEB-b-PEO Triblock Copolymer Soft Segments

Abstract

The elasticity of commonly known poly(butylene terephthalate)-poly(tetramethylene oxide) (PBT-PTMO)-based copoly(ether ester)s is increased by replacement of PTMO soft segments with poly-(ethylene oxide)-block-poly(ethylene-stat-butylene)-block-poly(ethylene oxide) (PEO-b-PEB-b-PEO) triblock copolymer soft segments containing a nonpolar middle block based on hydrogenated polybutadiene (PEB). The incorporation of this strongly incompatible PEB block resulted in the aimed increased phase separation between the PBT hard blocks and the soft segment phase, leading to a disperse PBT phase and hence to an increased elasticity. Dynamic shear experiments in combination with small-angle X-ray scattering revealed that crystallization of the PBT hard segments occurs from a microphase-separated melt. The resulting dispersed PBT hard phase in these materials is shown using transmission electron microscopy (TEM) and scanning force microscopy (SFM), whereas the increased elasticity is demonstrated using mechanical characterization. Hysteresis measurements reveal that the plastic deformation after recovery from 100% strain is only 1-6% (depending on composition) for the new PEB-containing copolyesters compared to 33% for a PBT-PTMO-based copoly(ether ester). The combination of results obtained with differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) points toward a complex morphology for the PEB-containing copolyesters. Five different phases exist: a crystalline pure PBT phase, pure amorphous PEB, and PBT phases and a PEO-rich phase besides an amorphous mixed PEO/PBT phase.

Synthesis and characteristics of poly(ethylene terephthalate) with EO‐PO‐EO triblock copolymers: A thermal and mechanical property study

“…Hence, five distinct phases were observed, including a crystalline pure PBT phase, pure amorphous PEB, PBT phases, and a PEO-rich phase besides an amorphous mixed PEO/PBT phase. 47 In this article, in order to copolymerize a PET-based multiblock polyether with high toughness and water absorption ability, a series of poly(ethylene terephthalate)-co-poly(ethylene glycol)-poly(propylene glycol)-poly (ethylene glycol) (PET-X%-E-P-E) with different composition ratio were synthesized. Furthermore, the effects of the E-P-E ratio on thermal, mechanical properties, crystallization behavior, and water absorption ability for copolymers were investigated.…”

Super‐ductile PBT alloy with excellent heat resistance

“…It is well known that the elongation at break of PBT drops seriously with ageing time even at 508C [2]. By contrast, a lot of articles are reported for the toughing by elastomeric modifiers, especially by core-shell rubber modifier, such as MBS (methylmethacrylate-butadiene-styrene terpolymer) and SEBS (hydrogenated styrene-butadiene-styrene block copolymer) [3][4][5][6][7][8]. Several studies described the toughening PBT by reactive blending with maleic anhydride grafted polyolefins and poly(ethylene-co-glycidyl methacrylate) (EGMA) [9][10][11][12][13][14][15].…”

Effects of co‐hard segments on the microstructure and properties thermoplastic poly(ether ester) elastomers

“…However, it does not change much with the variation of the content of the PBP co‐hard segments. This implies that the PTMO forms a distinct phase . The glass transition zones ( T g2 ) of some samples such as samples 3 and 6 are relatively wide, suggesting that the corresponding amorphous phases are mixtures of amorphous soft and hard segments.…”