Preparation of Acrylonitrile Modified Starch Grafting Dodecafluoroheptyl Methacrylate Polymer Emulsion and Its Application as Surface Sizing Agent

The surface sizing agent was synthesized through free radical polymerization,by using acrylonitrile modified starch as a dispersant,styrene(St) and butyl acrylate(BA) as monomers,dimethylaminoethyl methacrylate(DM) as cationic monomer,acrylamide (AM) as cross-linking monomer,and dodecafluoroheptyl methacrylate(FM) as functional monomer.The effects of oxidant,initiator and monomers on surface sizing were studied.The optimum synthesis conditions are as follows:the dosage of modified starch being 8%,FM being 0.3%,DM being 0.9%,AM being 3%,K2S2O8 being 0.5%,and m(St):m(BA) dosage being 2.5.And through testing the properties of papers,the size effect of modified starch graft copolymerization latex is better than that of the same condition of product without FM,particularly the size degree and the tensile strength of paper could improve obviously.