writer：Li Xiangyang; Hong Zhenfei; Sun Jie; Geng Yong; Huang Youju; An Haining; Ma Zhe; Zhao Baijin;Shao Chunguang; Fang Yapeng; Yang Chuanlu; Li Liangbin*
keywords：Phase Behavior,Biodegradable Poly(hexamethylene succinate-co-hexamethylene adipate) Copolymers,FTIR
source：期刊
specific source：J. Phys. Chem. B 2009, 113, 2695–2704
Issue time：2009年

Whether a phase separation or a cocrystallization occurs in poly(hexamethylene succinate-co-hexamethylene

adipate) (P(HS-co-HA)) copolymers was studied with a combination of wide-angle X-ray diffraction (WAXD)

and Fourier transform infrared (FTIR) spectroscopy. With HA as the majority, the presence of HS comonomers

leads to weakening and broadening of (10l) peaks in the X-ray fiber diffraction patterns, while a crystal

structure similar to PHS is formed in the copolymer with HS as the majority. The X-ray diffraction patterns

imply possible cocrystallization between HS and HA comonomers, but cannot lead to an unambiguous

conclusion, which was clarified with the compensative tool of FTIR. Following the characteristic absorption

bands of crystals, cocrystallization of HS and HA comonomers was observed in copolymers with HA

comonomer as the majority during which HA initiated the nucleation at high temperatures. With HA as

minority, cocrystallization of HS and HA can still be achieved with a fast quenching to below 0 °C, while a

phase separation occurs and only HS comonomer crystallizes at high temperatures. This demonstrates that

P(HS-co-HA) has an asymmetric phase diagram. Because of the sensitivity to local conformations, FTIR

spectroscopic method is demonstrated to be a powerful tool on study phase behaviors of polymers with similar

crystal structure.