Investigation of the physico-mechanical properties of electrospun PVDF/cellulose nanofibers.

The electro-activity and mechanical properties of PVDF depends mainly on the b-phase content and degree of crystallinity. In this study, cellulose fibers were used to improve these characteristics. This could be achieved because the hydroxyl groups on cellulose would force the fluorine atoms in PVDF to be in the trans-conformation, and the cellulose particles could act as nucleation centers. Electrospinning was used to prepare the PVDF/cellulose (nano)fibrous films, and this improved the total crystallinity and the formation of b-crystals. However, the presence and amount of cellulose in PVDF were found to have little influence on the b-phase content and on the total crystallinity of PVDF. Improvements in the extent of crystallinity and the b-phase content were primarily brought about by the chain- and crystal orientation as a result of electrospinning. The thermal stability of PVDF in the composites slightly increased with increasing cellulose content in the composites up to 1.0 wt %, while the modulus and tensile strength significantly increased up to the same filler level. The dielectric storage permittivity also increased with increasing cellulose content, but the presence of cellulose had no influence on the dynamics of the c- and b-relaxations of the PVDF