The effect of extrusion variables on the fundamental properties of tubular polythene film

Abstract

The mechanism of formation of tubular polythene film is a complicated process, and extensive studies have shown that the properties of the film made are influenced profoundly and in a complex way both by the processing conditions used by certain design features of the equipment. Studies of the effect of the extrusion variables on the more important film properties, both optical and mechanical, are reviewed in this paper. The results are discussed in terms of the fundamental nature of polythene film, its surface, its crystalline structure and its orientation.

Melt fracture of polystyrene

“…There is general agreement among the workers who have investigated sharkskin that, for a particular polymer, shark skin occurs at a fixed linear velocity rather than at a cri tical shear rate (6,7,9). This is well illustrated by Clegg (7) who showed that the onset of sharkskin is independent of die diameter but considerably delayed by increasing temperature.…”

Effect of crystallinity on surface morphology and light transmittance of poly(vinylidene fluoride‐co‐hexafluoropropylene) thin film

“…In addition, a lot of investigations have shown that the majority of light scattering is resulted from the surface roughness, and in this case, the dominating cause for such roughness is crystallization on and beneath the surface. [27][28][29][30][31] Therefore, we assume that the transmittance loss of PVDF and HFP11 thin films can be attributed to light scattering from surface textures derived from crystalline domain and its grain boundaries. Figure 5 illustrates surface morphology of the PVDF and P(VDF-co-HFP) copolymer films.…”

Orientation, crystallization, and haze development in tubular film extrusion

“…It was first given extensive attention in the 1950s and early 1 9 6 0~~~"~ The first serious discussions related to tubular film characterization are those of Huck and Clegg. 48 A quantitative method of experimental investigation was devised by Clampitt et al49 This involves the measurement of the transmissivity T defined by 34 VOL. 8, NO.…”