Crystallization behavior,tensile behavior and hydrophilicity of poly(vinylidene fluoride)/polyethylene glycol blends

In this study, polyethylene glycol (PEG) of different molecular weight was added into poly(vinylidene fluoride) (PVDF) through melt blending. The hydrophilicity, processability, mechanical properties of the blends were investigated. Moreover, to understand fully, the crystallization and melting behavior, crystalline structure, molecular interactions of the blends were also studied. Results revealed that the addition of PEG evidently enhances the ductile and reduces the rheological torque of PVDF, what’s more, the contact angle of the blends with water was greatly reduced. The solid surface tension γ_s, chromatic dispersion part γ _s ^d and polar part γ _s ^p suggested the surface tension of the blend gradually increased from 38.31 to 55.65 mJ/m² with the increase of PEG-20000 content.Wherein the dispersion part of the tension changed little, the polar part of the tension increased significantly from 5.74 to 20.41 mJ/m², indicating that the addition of PEG greatly enhanced the polar part of surface tension of the blend, and therefore evidently enlarged the hydrophilic property of the blends. Besides, to elucidate the related effecting mechanism, the crystallization and molecular interaction of the blends were also studied.