Fabrication of high modulus films by solid state rolling

Abstract

Solid state rolling of semicrystalline polymers represents a high speed process for producing oriented, high modulus films, tapes, and sheets. The important process variables include roll temperature, thickness of initial sheet, roll speed, take-up tension, roll diameter, and initial morphological state of the polymer. Roll temperature controls both the extent of maximum deformation and the rate of rolling. A minimum temperature exists for each polymer below which the orientation process is sharply limited. This condition is similar to the limitation present in the hydrostatic extrusion process, in which the alpha crystallization temperature limits the orientation process. Roll speeds as high as 20 m/min have been realized. It is apparent that film thickness and thickness reduction ratio have a strong effect on the ultimate rolling rate. The process, as currently practiced, is adiabatic, and therefore, heat transfer limited. The take-up tension influences the extent of orientation in the amorphous phase of the polymer. This in turn affects its thermal and chemical stability. The effect of roll diameter is to limit the extent of thickness reduction by causing roll-film slippage when the roll diameter to thickness reduction ratio is below some as yet undetermined value. The initial morphological state of the polymer affects the amount of crystalline deformation possible, the surface texture of the rolled film, and the tear resistance of the oriented film.

Short Review on Conductive Polymer Composites as Functional Materials

“…This is due to the thermal resistance effect caused by local clustering is dominated by particle-to-particle channelling. In the following research, Big [20] also found that the thermal conductivity can be drastically increased when the filler loading level is high. This explains that the connection of fillers at high loading levels improve heat conduction efficiently.…”

Dynamic Mechanical Properties of Rolled Polypropylene Sheets

“…Plastic deformation has been applied to the processing or forming of semi-crystalline polymers. Various processing methods such as drawing 3,4 , hydrostatic extrusion [5][6][7][8] , die-drawing 9 , roller-drawing 10,11 , and rolling [12][13][14][15][16][17][18][19][20][21][22][23][24][25] have been conducted. In several publications, drawing techniques for polymer sheets using rollers or heating devices have been described.…”