Effects of filler type and mixing method on the physical properties of a reinforced semirigid liquid crystal polymer

Semirigid liquid crystalline polymers (LCPs) show some advantages with respect to rigid LCP: in particular lower processing temperatures, better compatibility with flexible thermoplastics, but also some disadvantages. Thermal resistance of rigid LCPs is much better and the maximum working temperature is, in general, very high. The thermomechanical properties can be improved by adding inorganic fillers. In this work processing, mechanical and thermomechanical properties of a filled semirigid liquid crystal copolyester are reported. Several inorganic fillers have been used in order to put in evidence the influence of shape and dimensions of the particles on the properties of the filled materials. Both elastic modulus and tensile strength improve by increasing the filler content while the elongation at break decreases. The more eclatant improvement, however, arises from the creep and from thermomechanical behaviour. The creep rate is drastically reduced and the maximum working temperature is remarkably increased. The glass fibre filled polymer displays the best results. The only negative feature is the rise of the power necessary to process the material. Copyright (C) 1996 Elsevier Science Ltd