| Polyvinyl Alcohol (PVA), Acrylics and Starches are major materials in warp sizing. PVA is regarded as non-tidy sizing agents, for PVA is hard to be biodegradated. Acrylics are easy to absorb the moisture and to readhere each other, so it can not be used individually. Starches have been used as sizing material for a long time. Nowadays, of all the sizing agents starches have amounted to about 69% of all the sizing agents. Raw starches have many disadvantages, such as bad film-forming ability, bad flexability, high glass temperature and low adhension for hydrophobic fibers. Due to above reseaons, PVA has become the essential part of sizing liquid, especially for polyester/cotton blended yarn, which will heavily pollute the enviroments when the rest liquid in the sizing box gone out and desized from the yarn in the following process. To avoid using PVA in sizing, modifying starch is a good way; and grafted starch copolymer is regarded as one of the best products among all the modified starches.Some provinces in westen China, such as Shaanxi, Gansu and Ningxia are rich in Potatoes. In Northen Shaanxi about 0.5 billion kilograms potatoes can not be properly used every year. The CCTV asked the technicians to find a way of using these potatoes. Some famous starch companies in Europe have already paied much attnention to the potato starch research.Suspension method is the traditional way to get starch grafted, which has several shortcomings. The process is complicated and hard to controll, and it also takes a long time. The products made by this way are in liquid states, thus their applications are limited. The rapid development of Microwave Induced Organic Reaction Enhancement Chemistry makes it possible that the starch graft sizing agents can be made in solid states.First, in this paper, we have designed the molecular structure of the graft starch according to the principle of using less PVA. We think that the graft starch should contain hydrophobic monomer and hydrophilic monomer. To meet this demands butyl acrylate and acrylic acid are chosen in this research.Secondly, in order to study the grafting process of starch graft, we have studied thegraftig rules of butyl acrylate and acrylic acid onto starch under microwave radiation respectively. These rules made a foundation of grafting butyl acrylate and acrylic acid onto starch. In fact it is necessary to study the grafting process of above two monomers onto starch, for the two grafting starch copolymers are also useful.The starch grafting process includes the ratio of hydrophobic monomer and hydrophilic monomer, total weight of monomers, polymerization time, and interfacial solution. These factors affect the rules of the starch grafting. Experiments show that the grafting starch copolymers water solubility and adhesion to yarn depend on the ratio of hydrophobic monomer and hydrophilic monomer and total weight of monomers. Our research indicate that the ideal grafting starch sizing agent should be made by the follwing way: the ratio of hydrophilic monomer and hydrophobic monomer is 1:2, total weight of monomers is 40% of that of starch, polymerization time is 9mins, and a mount of interfacial solution is essential.We have also studied the temperature curves of starch and monomers under microwave radiation, which are foundations of deciding the polymerization time .Thirdly, this paper has also investigated the relationship between the molecular weight of grafted poly and the properties of grafted starch. The molecular weight of grafted poly has a close effect on grafting starch's water solubility. The ideal molecular weight of grafted poly should be about ×103.Fourthly, by using optimum theory, we have optimized the grafting process,which based on the study of single monomer grafted onto starch. According to the optimization result, we have synthesized the grafted starch. Infrared spectrum (IR), SEM and DSC show that the starch and the monomers have been rearly synthesized under the microwave radiation. By controlling the molecular weight of... |
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