Research On Starch Graft Copolymer As Warp Sizes Instead Of PVA

There are mainly starch, PVA and polyacrylic size as sizing materials in textile warp sizing. Through PVA is excellent size, it is difficult to biodegrade and pollutes environment. Nowadays, PVA has amounted to twenty percent of sizes and has approximately 170,000 tons in order that environmental pollution is very serious.Some new sizes must be researched in order to solve the environmental pollution of PVA. Starch graft copolymer can replace PVA because it have excellent sizing and biodegradable properties. So far it has some defects, such as low grafting ratio, compliated process, high cost and poor properties. It is limited to replace PVA.In sizing it is very impotant of adhesivity and film-forming property in acordance with demands of sizing. According to the relation of structure and properties molecular structure model of grafted chain is developed. Grafted chain is a single bond structure of long lined carbon chain which have a large number of ester groups and just the right amount of hydrophilic groups. In other words, grafted monomer is mainly acrylate and hydrophilic monomer is auxiliary.Because acrylates are difficult to graft onto starch macromolecules grafting ratio is usually low when eerie initiator has not been used in graft copolymerization. DHU-1 initator is composed of oxidizer and reducer by anylasing some kinds of intiators. DHU-1 redox initator has not only outstanding initiating property, but also is cheap and plentiful. The maximum grafting ratio is 15% and more higher than some successful graft starch copolymers. DHU-1 initator can replace eerie salt to produce starch graft copolymers.Ethyl acrylate and acrylamide are used after some common acrylicmonomers are anylased. The amount of acrylamide does merely meet the need of solubility of starch graft copolymer. The relation of grafting ratio and sizing have been studied. The optimum grafting ratio is about 12%. By means of single factor experiments major factors affecting the polymerization reaction are thoroughly investigated including initiator concentration, monomer concentration, polymerization time, polymerization temperature, starch/water ratio and the way of addition of initiator and monomer. By way of orthogonal design the optimum conditions are as follows: oxidizer concentration, 0.125%; reducer concentration, 0.4%; ethyl acrylate concentration, 20%; acrylamide concentration, 1.4%; starch/water ratio, 1:3; polymerization time, 3h; polymerization temperature, 40 ℃. Initiator and monomers are added continuously in lh. Grafting ratio, grafting efficiency and total monomer conversion are 12.64%, 62.07% and 99.86%, respectively.The effect of pretreatment and aftertreatment on graft polymerization onto starch have been investigated. New process that graft polymerization is carried out before acidification is used in order that the process of production are simplified.Our starch graft copolymer not only can be biodegraded completely, but also is cheap. In contrast with the mixture sizes of 70% PVA and 30% oxidized starch it can save forty-nine percent of cost. It have outstanding properties of sizing and can replace PVA completely in warp sizing of 65/35 13tex T/C. Tensile strength, elonglation and hairiness are superior to the mixture sizes of 70% PVA and 30% oxidized starch. Abrasion resistance is equally matched and overcome the defect of other starch graft copolymers.