Preparation and characterization of regenerated cellulose/poly (vinylidene fluoride) (PVDF) blend films

Regenerated cellulose/poly (vinylidene fluoride) (PVDF) blend film was successfully prepared through coagulating their N,N-dimethyl acetamide (DMAC)/LiCl solution with water. The toughness of the blend films, compared with virgin regenerated cellulose film, was significantly improved when the content of PVDF in blend films was no more than 20 wt.%. The elongation at break increased from 12% to 34%, and the tensile strength was also improved from 89 to 106 MPa with the addition of PVDF till 20 wt.%. The mechanical properties of the blend films became worse when the content of PVDF in blend films was more than 20%. The oxygen permeability was firstly decreased from 2.3 1 (-10) to 0.036 1 (-10)cm(3)cm/cm(2)s Pa when the PVDF content increased from 0 to 5 wt.% in the blend films. Afterwards, the oxygen permeability would increase with the increasing of the PVDF content. The film showed some pores when the loading level of PVDF was more than 50%. The pore size of blend film became larger with the increasing of PVDF content. These phenomena were well correlated to the crystallinity, hydrogen bonds and morphologies of the blend films.