MECHANICAL-PROPERTIES AND STRUCTURE OF METHACRYLAMIDE (MAA) GRAFTED SILK FIBERS

Graft copolymerization was performed on silk fibres by using methacryl amide (MAA), and changes in the mechanical properties and structure we re investigated, Young's modulus of the MAA grafted silk fibre was ana lysed by applying the law of mixture by regarding the MAA grafted silk fibres as a composite comprising silk fibres and a MAA polymer resin, Young's modulus of the MAA polymer in the MAA grafted fibres was calc ulated to be approximately 4.6 GPa, which was larger than the value of a MAA polymer film, The MAA polymer in the MAA grafted silk fibres wa s oriented with respect to the fibre axis, When the volume fraction of the fibre in the MAA grafted silk fibres was more than 0.8, the tensi le strength of the MAA grafted silk fibres agreed with the strength ca lculated by assuming that the failure of the MAA grafted silk fibres w as caused by the failure of silk fibres and the MAA polymer was strain ed to the same extent as the silk fibres, The wide-angle X-ray diffrac tion measurements showed that crystallites in silk fibres treated with MAA to a large polymer add-on were destroyed by this treatment. The f racture of the MAA polymer matrix as well as the destruction of crysta llites in silk fibres influenced the strength of the MAA grafted silk fibres when the volume fraction of the fibre was less than 0.8.