Abstract
The discontinuous Kevlar fiber-reinforced composites which structure was random-in-plain fiber orientation were prepared by solvent-casting/melt processing method. The interfacial interaction of Kevlar fibers [original Kevlar tribe.(O-K), ac.olein-grafted Kevlar fibers(AL-g-K), methacrylonitrile-grafted Kevlar fiber(MAN-g-K)] with matrix polymers(Phenoxy, PMMA, and SAN) was investigated by dynamic mechanical analysis, thermomechanical analysis and FT-IR spectroscopy. In the dynamic mechanical analysis at 11 Hz, the storage modulus (E') and the decline temperature of were found to increase in the order of MAN-g-K, AL-g-K, and O-K. The tan peak temperature related to glass transition increased in the same order. By ther-momechanical analysis, the trends mentioned above were also seen for T obtained from the first displacement change as a function of temperature. However, the second transition which appeared at higher temperature may be due to interfacial interaction between the fiber and the matrix. Two onset temperatures of TMA displacement change increased also in the same order of MAN-g-K, AL-g-K, and O-K. By FT-IR spectroscopy, it was found that characteristic peaks(phenoxy : C-O-C(240 cm ), PMMA : C=O(1720 cm ), and SAN : C=N(2240 cm )) of composite films shifted to the amide peak (amide I: 1650 cm & amide II : 1540 cm ) of original Kevlar fiber, however, the amide peak of original and grafted Kevlar fibers of composites moved to the characteristic peaks of matrix polymers. From these results, it may be concluded that the interfacial interaction between reinforcement fibers and the matrix polymers (phenoxy, PMMA and SAN) increased in the order of MAN-g-K, AL-g-K and O-K.
