Structure and Mechanical Properties and of PVDF Monofilament obtained by the laser-heated drawing

Abstract

The poly(vinylidene fluoride) monofilaments having diameter of 0.2 - 0.7 mm were drawn with heating by laser irradiation. It is estimated that the filament which have a diameter of 0.2 mm can be heated almost uniformly by the laser irradiation whereas only outer layer of the filament of 0.7 mm can be heated. Therefore, the 0.7 mm filament cannot be drawn stably under low drawing stress. And for the higher draw ratio, the drawing stress concentrated to the central part of the filament. The cross-sectional stress deviation in the filament with diameter of 0.7mm causes the α-form crystal remaining up to higher drawing stress, and restraining tensile strength of drawn filaments. By redrawing of the drawn filament still remaining α-form crystal not only improves the attaining tensile strength but also reduces the thermal shrinkage of drawn filaments.