STUDY ON THE WATER RESISTANCE OF STARCH GRAFTED POLYMERS

摘要

Starch is a green chemical raw material with characteristics that include abundant availability, low price and complete degradation in the environment. As a surface sizing agent, its application is limited because of its effects on water resistance, film forming and sizing. So the sizing agent is commonly used in a variety of modified starch products. Starch graft polymer is one of the most important modifications of starch. The copolymer obtained by means of a grafting process, using starch and several monomers, is used in corrugated paper and paperboard to improve the water resistance. First, the initiator produces free radicals by dissociation which can initiate reaction with the starch. Then the initiator initiates vinyl or acrylic monomers, which will be grafted on the starch. The initiator is important to the chain initiation which is related to the possibility of the monomers that can be initiated, rate of initiation, grafting reaction time, percent grafting and so on. Using the H2O2-FeSO4 system as an initiator, styrene and butyl acrylate as monomers，starch as a skeleton, the surface sizing agent which had the water resistance was synthesized. FTIR was used to detect if the monomers had been grafted to the starch. By measuring the water resistance and grafting ratio, the best amount of catalyst and the amount of monomer were obtained. Simultaneously, the grafted starch was used for emulsifying AKD, which had got a better water resistance.