Characterization of a fiber reinforced semirigid liquid crystalline polymer

Abstract

In this work, samples of a semirigid Liquid crystalline polymer reinforced with carbon and glass fibers has been characterized. Semirigid liquid crystalline polymers (LCPs) show some advantages with respect to rigid LCPs: in particular lower processing temperatures, and better compatibility with flexible thermoplastics, but also some disadvantages: lower mechanical properties and poor thermomechanical resistance. Both properties can be improved by adding inorganic fillers. Although elastic modulus and tensile strength of the glass fiber filled LCP improve remarkably with increasing the filler content, the same properties for the carbon fiber-filled samples do not increase with increasing ti-re content of the fiber; rather a maximum tensile strength is observed at about 20% of carbon fibers. The thermomechanical and the creep behavior are also drastically improved by adding the fibers. Ln particular, the creep curve is shifted by several decades toward longer times, and the heat distortion temperature increases about 60 degrees C by adding 20% of carbon fibers. The processability is, on the other hand, significantly worsened. By comparing the results for the carbon fiber-filled samples with those obtained for the same polymer reinforced with glass fibers, it is worth noting that the properties are similar, but lower amounts of carbon fibers are needed to obtain the same mechanical and thermomechanical properties. (C) 1997 John Wiley & Sons, Inc.