Studies On The Function Of Hydrophilic Constituent Units Of PALS Sizing Agents

In order to overcome the defeats of sizing performance of polyacrylate size (PALS) and develop the polyacrylate sizes which will be environmental and better performance, the paper investigated the sizing properties and biodegradability of polyacrylate sizes.The polyacrylate sizes were prepared in ethanol through a free radical copolymerization of butyl acrylate (BA) with acrylic acid(AA), methacrylic acid(MAA) and itaconic acid(IA), respectively. Influences of the hydrophilic units formed by the three monomers were evaluated with regard to the properties of sizing film, adhesion to fibers and the biodegradability of polyacrylate sizes. The potential relationship between the properties and content of itaconic acid unit was revealed. The results manifested that the performance of the polyacrylate sizes is strongly depended on the type and content of the hydrophilic units in the maceomolecular chains. The adhesion of the polyacrylate sizes to polyester fibers was enhanced through introducing IA units; the adhesion to cotton fibers was strengthened by introducing AA units. The copolymerization with appropriate ratio of IA to BA showed the highest adhesion to polyester fibers and favorable film characteristics such as breaking strength and breaking elongation. The molar ratio of IA to BA was found to be about 15:70. With the decrease of content of IA units in the poly[(itaconic acid)-co-(butyl acrylate)], the abrasion resistance of sizing film was reinforced. Itaconic acid should be used as a hydrophilic monomer during the preparation of polyacrylate sizes via solution polymerization when polyacrylate sizes are used for sizing polyester yarns. The contribution of the hydrophilic units for improving the biodegradability of the polyacrylate sizes followed the order: P(MAA/BA) < P(IA/BA)< P(AA/BA). The biodegradability of P(IA/BA) enhanced with the increase of content of IA units as the hydrophilic units.The effects of the blending ratio of the polyacrylate sizes/starch blend film were investigated. The breaking strength, breaking elongation and wear loss of film were used to quantitatively characterize the film indexes. The experiment results demonstrated that the blending ratio shows evident influences on the properties of the film.As the content of polyacrylate size in the film rises, the breaking elongation increases.