Jutarat Prachayawarakorn and Wattana Klairatsamee

pp. 1233 - 1242

Abstract

Mulberry silks were chemically modified in order to increase weight gain, resulting from degumming
process using graft copolymerisation technique with vinyl monomers, i.e. MMA, MAA and MMA/MAA.
Due to the appearance of PMMA homopolymer granules adhered on the MMA- and MMA/MAA-grafted
silk surfaces resulting in surface roughness when silk was grafted by MMA in water, the influence of grafting
solvents was examined, using different water/ethanol volume ratios of 100/0, 75/25, 50/50, 25/75 and 0/100.
FTIR spectra of the grafted silks presented the absorption bands of the vinyl monomers used for the grafting
process. In addition, high values of % polymer add-on were obtained for all of the grafted silks. It was also
found that the suitable solvents were 25/75 water/ethanol for the silk grafted by MMA and MMA/MAA, and
water for the silk grafted by MAA, in order to get the smooth grafted silk surface and high polymer add-on.
Moreover, all the grafted silks showed slightly greater stiffness, as indicated by the increase of Young's
modulus and the decrease of elongation.