Effects of Poly(cyclohexanedimethylene terephthalate) on Microstructures, Crystallization Behavior and Properties of the Poly(ester ether) Elastomers.

Yi-Cheng Feng,Hui Zhao,Guo-Hua Hu,Qun-Chao Zhang,Tao Jiang,Tong-Hui Hao

doi:10.3390/ma10070694

Abstract

To understand the role of molecular structure on the crystallization behavior of copolyester in thermoplastic poly(ether ester) elastomers (TPEEs), series of poly(butylene-co-1,4-cyclohexanedimethylene terephthalate) (P(BT-co-CT))-b-poly(tetramethylene glycol) (PTMG) are synthesized through molten polycondensation process. The effects of poly(cyclohexanedimethylene terephthalate) (PCT) content on the copolymer are investigated by Fourier transform infrared spectroscopy (FT-IR), 1H and 13C nuclear magnetic resonance (NMR), gel permeation chromatographs (GPC), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), mechanical, and visible light transmittance tests. FT-IR and NMR results confirm the incorporation of PCT onto the copolymer. WAXD and DSC indicate that the crystalline structure of the copolymers changed from α-PBT lattice to trans-PCT lattice when the molar fraction of PCT (MPCT) is above 30%, while both crystallization and melting temperatures reach the minima. An increase in MPCT led to an increase in the number sequence length of PCT, the thermal stability and the visible light transmittance of the copolymer, but to a slight decrease in tensile strength and elastic modulus.

Highlights

Thermoplastic poly(ether ester) elastomers (TPEEs) are usually block copolymers composed of polyester segment and polyether segment [1,2,3]
Poly(butylene terephthalate) (PBT)-b-poly(tetramethylene glycol) (PTMG) is one of the most typical TPEEs with useful properties such as high tensile strength and elastic modulus. This is due to the thermodynamic immiscibility between the hard and soft segments, which dictates the crystallization behavior, morphology, and thermal and mechanical properties of PBT-b-PTMG [8,9]
The peaks at 2941 and 2862 cm−1 are assigned to the asymmetric and symmetric aliphatic C–H stretching vibrations of PBT [10]

Summary

Introduction

Thermoplastic poly(ether ester) elastomers (TPEEs) are usually block copolymers composed of polyester segment (hard segment) and polyether segment (soft segment) [1,2,3]. In addition to possessing rubber-like properties, TPEEs can be processed similar to thermoplastics. Because of the unique processing and mechanical properties, TPEEs are considered to be “third-generation synthetic rubbers”, which are applied in numerous applications such as electronics and automotive industries, in skin tissue engineering, and so on [4,5,6,7]. Poly(butylene terephthalate) (PBT)-b-poly(tetramethylene glycol) (PTMG) is one of the most typical TPEEs with useful properties such as high tensile strength and elastic modulus. This is due to the thermodynamic immiscibility between the hard and soft segments, which dictates the crystallization behavior, morphology, and thermal and mechanical properties of PBT-b-PTMG [8,9]

Methods

Results

Conclusion