Rolltrusion processing of polypropylene for property improvement

These were made using a Perkin-Elmer DSC2 calorimeter fitted with computer integration accessories. Baseline corrections were made for all thermograms whatever the test run conditions. The significance of these measurements has already been addressed in the literature [5] and other aspects of the work will be addressed elsewhere. 

Wide angle X-ray measurements (WAXS) were made in three directions X, Y and Z for each specimen using monochromatic CuK(a)-radiation with an XRD5 GE diffractometer fitted with a graphite monochromator 

Wear rates were measured for roUtruded PP investigated for planes perpendicular to X, Y and Z directions. Anisotropic properties have been reported [8]. 

Using a modified commercial software package termed ABAQUS (initially formulated for metalworking technology), an attempt was made to simulate some features of the rolltrusion process at several deformation ratios X 5. Simulated deformed grid patterns compare favorably with 

The high stresses which the polymer experiences in the roller nip region transform spherulites into well-organized lamellae that are connected by tie molecules to provide strength enhancement according to their populations expressed as Z Y X XYZ (isotropic condition) of initial workpiece. XYZ denotes the starting sample. The special thermotropic network that is produced via rolltrusion is one in which the crystallites function in a sense as the crosslinks, akin to a conventional crosslinked system in most of its mechanical functions. 

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In rolled (see the chapter entitled Rolltrusion processing of polypropylene for property improvement) sheet, the c- and fl -axes are mixedly oriented in the rolling direction and the h-axes are random about it. With increasing compression ratio, the molecular orientation increases and the crystallinity decreases, resulting in an increase in the tensile modulus and a decrease in the elongation. 

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