Abstract
Viscose rayon was graft copolymerized by γ-ray irradiation, being immersed in the solution system of styrene-acetone-water. From the results obtained by preliminary experiments, it was found that the water content of the solution system, as well as the supply of monomer from the solution system, played an important part in acceleration of graft copolymerization.
In order to check the completeness of homopolymer extraction, the grafted rayon, extracted beforehand for 24hrs., was ground to powder in dry ice-methanol and then extracted with benzene for 60hrs. by using soxhlet apparatus. It shows the existence of homopolymer in fiber that the amount of re-extracted polystyrene attains more than 20% on the base of original graft polystyrene.
By the photomicroscopic observation on the cross section of grafted rayon, using the various method of dyeing, the distribution of graft polystyrene in fiber was investigated. The results showed that polystyrene deposited in the outer layer of the cross section at low percent of grafting (for example 35%), penetrating into the inner layer at high percent of grafting (for example 212%). Furthermore, graft polystyrene was isolated from cellulose back bone by using the acid hydrolysis method and intrinsic viscosity was measured by using benzene and dioxane as solvent. It is interesting that it's intrinsic viscosity is very large compared with that of homopolymer. In addition, the various properties of grafted rayon were measured and discussed.
