Journal of Applied Polymer Science, Vol.103, No.6, 3899-3906, 2007
Wear and mechanical properties of reactive thermotropic liquid crystalline polymer/unsaturated polyester/glass fiber hybrid composites
To improve the performance of unsaturated polyester (UP) under cold-heat alternate temperature, self-synthesized reactive thermotropic liquid crystalline polymer (TLCP)-methacryloyl copolymer (LCMC), UP, and glass fiber (GF) hybrid composites was prepared by molding technology. The apparent activation energy and crystal behavior analysis of LCMC/UP blends were investigated by Differential scanning calorimetry and X-ray diffraction (XRD), respectively, the results showed that the addition of LCMC can reduce apparent activation energy and accelerate the curing reaction of UP, the XRD analysis indicated that the crystal phase of LCMC still exist in the blends after blending with UP. The effect of LCMC content on the properties of LCMC/UP/GF hybrid composites such as impact strength, bending strength, and ring-on-block wear were also investigated through static mechanical tests and wear tests. The mechanical properties of hybrid composites increased significantly because of the addition of LCMC. The wear tests showed that LCMC can improve the wear resistance of the UP/GF/LCMC hybrid composites even though the content of LCMC was at a relatively low level (5-7.5 wt %). This makes it possible to develop novel kind of UP-based materials with good wear resistance for various applications. The Worn surface was observed by scanning electron microscopy (SEM) and the mechanism for the improvement is discussed in this paper. (c) 2006 Wiley Periodicals, Inc.
Keywords:thermotropic liquid crystalline polymer;unsaturated polyester;hybrid composites;mechanical properties;tribological property