Graft copolymerization of acrylic acid onto pet fiber using Ce (IV) initiator

Abstract

This thesis deals with the improvement the drawbacks of PET fiber, such as moisture regain and dyeability at low temperature by grafting technique. Ceric ammonium nitrate (CAN) initiated graft copolymerization of acrylic acid onto PET fiber was carried out. The variables affecting the grafted PET were investigated. The optimum condition of graft copolymer to obtain the optimum percentage of graft yield of 43.6% was found as follows: 323 K reaction temperature, 1-h reaction time, 1.82 mmol of CAN, 2.19 mol of acrylic acid, and 0.80 mol of nitric acid. The extent of acrylic acid homopolymerization affected the acrylic acid/PET grafting system. The poly(acrylic acid) homopolymer was characterized by the infrared spectroscopy. The morphology of the graft copolymer was characterized by scanning electron microscope (SEM). Based on the morphology of the PET fiber, it could be concluded that CAN in dilute nitric acid is redox initiator for the graft copolymerization of acrylic acid/PET system. The grafted PET fiber showed an increase in improved moisture regain to reach a maximum of 2.0% for 39.5% graft yield. The dyeability with the basic dye (methylene blue) and disperse dye (CI disperse blue 79) significantly increased by 100% and 22%, respectively, due to the grafting onto PET fiber. Both tenacity and elongation gradually decreased by 51.15% and 28.90%, respectively, with increasing graft yield, which reduced the fiber service lifespan. TGA curves of the acrylic acid grafted PET fiber indicated that the grafting did not change the decomposition temperature of PET fiber. A mechanism for grafting PET with acrylic acid using the ceric(IV) redox initiation was proposed.