Fiber(5 g) and silane (0.5 g) were put in a flask with the proper volume of acetone. After agitation for half an hour, the flask was sealed with a polytetrafluoroethylene film and then kept for 12 h at room temperature. The samples were then washed with acetone toremove compounds not covalently bonded to the fiber, and dried at 80 8C in an oven to a constant weight.