Whisker-reinforced Thermosetting Resin Matrix

In this article, thermoset resin composites reinforced with whiskers such as aluminum borate whiskers or potassium titanate whiskers pretreated with silicone coupling agent KH550 in different solvents were prepared by casting methods, The effects of whiskers on curing process were studied by gelation test and IR, and the mechanical and thermal properties of the composites were also mainly investigated through changing the amount, kind,size of whiskers and the mixing process. The morphologies of fracture surface were observed and analyzed by SEM to study the scattering degree of the whiskers and to find out the reinforcing mechanism of whiskers,, It was found that whiskers had almost no influence on the curing process, that the reinforcement of aluminum borate whiskers was much stronger than potassium titanate whiskers, and the bigger the aspect ratio of whiskers was, the better the properties of the composites was at certain range of the size of whiskers. What' smore, the coupling solvents played an important role on the reinforcing effect of whiskers, as well as the PH of them.The results of properties indicated that the bending strength of composites increased with the addition of 15wt% whiskers or so , thereafter it decreased slowly with increasing whiskers; but the impact strength unchanged or decreased with the addition of whiskers; the change of thermal properties with the content of whiskers was the same as the bending strength with it. In a word, the finest composites were obtained when the content of whiskers was about 15wt%. Another new mixing process could markedly improve the properties of the composites due to the better scattering of whiskers. We were delighted to find that the blending use of whiskers and glass cloth could also cause the great improvement of the properties of the composites ?SEM analysis demonstrated that there was an much more serious agglomeration of whiskers in the composites by the old mixing process than that by the new one, and that the toughening mechanism of whiskers was very complex and consisted of whisker-pull-out and crack deflection etc.