GRAFT-POLYMERIZATION OF GLYCIDYL METHACRYLATE ONTO POLYETHYLENE TEREPHTHALATE FIBERS BY INITIATOR

Abstract

Glycidyl methacrylate (GMA) was graft-polymerized upon undrawn polyethylene terephthalate (PET) fiber and commercial PET fiber, in order to improve their dyeability utilizing the reactivity of its epoxy-ring with dyestuffs which have phenolic hydroxyl or amino groups.The graft reactions were carried out in aqueous solutions of dimethyl formamide (DMF) in which benzoyl peroxide (BPO) as the initiator and GMA as the monomer were dissolved.Since the commerical fibers has a poor reactivity the fibers was treated with benzyl alcohol at 150°C for 1 hr. preceeding the graft-polymerization.In the media of aqueous DMF, the graft polymer of GMA was given rise to opening of the epoxy-ring by water. At the content of DMF below 80% in the aqueous solution, the rate of the ring-opening increased with increase of water content in the solution, giving rise to gelation by cross-linking or net-work formation between hydroxyl formed and epoxy groups. It was difficult to extract the homopolymer, giving rise to a over estimation of the apparent grafting per cent of GMA. At the content of DMF above 80% in the solution, no ring-opening occured and the grafting per cent of GMA, measured from the weight increase of the sample, coincided with that estimated from the epoxy value. The graft reaction was, therefore, carried out in the 80% DMF solution in water.The grafting per cent of GMA, measured at a certain reaction time, varied with BPO concentration and had a maximum in the range of 0.005_??_0.01 mol/1 of BPO.The activation energy for the grafting is estimated as 14.7 Kcal/l for both the undrawn and the pretreated commercial PET.Mechanical properties such as tenacity, yield value, initial modulus and elongation of various grafted samples of the pretreated commercial PET were unchanged by the grafting. Dyeability of the grafted undrawn and commercial PET was examined by the use of Orange II. The ungrafted fibers lack dyeability. On the other hand, the dyeability of the grafted fibers increased with the increase of the grafting per cent of GMA. Orang II may react with the epoxy group of the graft polymer in pyridine. No decolorization of the dyed samples took place both in hot water and in pyridine.