Dynamic viscoelasticity of hybrid kevlar and glass fiber reinforced LLDPE in the molten state

摘要

Kevlar and glass fibers were used to reinforce linear low density polyethylene (LLDPE), and composite sheets of 0.8, 1.5 and 2.5 mm thicknesses were obtained by using a compression molding technique. Dynamic viscoelastic properties of nonhybrid and hybrid composites of various compositions at 200 deg C are evaluated. Storage modulus (G') and loss modulus (G") increase with angular frequency (omega) and reinforcement. Replacement of glass fiber by Kevlar at constant loading of fibers in LLDPE increases the value of G', G" and eta'.The fractured surface of composite shows the gradient orientation of fibers particularly in 2.5 mm thick sheet. Top and bottom layers show relatively two-dimensional orientation as compared to the middle layer, which showns random orientation. The orientation of fibers decreases G' and eta' of Kevlar fiber and hybrid fiber reinforced LLDPE composites. The effect of change in distance between parallel plate of rheometer (change in strain amplitude) on dynamic rheological properties is studied and reported here.