Influence of Aliphatic Polyesters on the γ Phase Crystallization of Poly(vinylidene fluoride)
Tiantian Song, Yuxin Wang, Huihui Li, Haijun Wang, Xiaoli Sun, Shouke Yan
Abstract
The polar phase of poly(vinylidene fluoride) (PVDF) is attractive for fabricating electroactive devices. However, the nonpolar α form is thermodynamically most accessible during the crystallization process. Here three types of aliphatic polyesters are chosen for blending with PVDF to explore their effect on inducing polar γ phase crystallization of PVDF. It is found that the ability of γ phase nucleation of PVDF enhances as the blend ratio of aliphatic polyesters and isothermal crystallization temperature increase. Poly(butylene succinate) (PBS) with highest melting temperature shows the highest ability for inducing γ phase crystallization. For example, the pure γ phase has been obtained under an appropriate blend ratio and isothermal crystallization temperature in PVDF/PBS blends. This is attributed to the hydrogen bonding interaction of H atoms in PVDF with carbonyls in PBS and the slow diffusion rate of PBS chains in PVDF. The addition of PBS lowers the folding surface free energy of the γ phase. This work offers a reference for selecting a suitable blending system to obtain pure γ phase PVDF and contribute to a better understanding of the relationship between intermolecular interaction and polymorphic phase selection.