Starch Phosphate Grafting Of Acrylamide Cationic Polymer Paper Synthesis And Application Of Increased Dry Strength Agent

Starch and its derivatives have become the important chemical additives for paper-making industry,because of their special characteristics such as abundant resources in nature,comparatively low prices for their production,easily chemical modification,and bio-degradation etc.And graft-copolymerization starch has its own advantages,like the simple polymerization process,excellent effectiveness on increasing paper strength properties,the steady quality of its production for storage,the convenience for its usage, and the friendly-environment of its productions etc.Consequently,this kind of starch-production has the vast application and the great market of paper industry.On the basis of real circumstances and conditions of paper industry in our nation,this paper mainly studied the graft copolymerization process of cation-polyacrylamide with phosphate starch ester(sp-g-cpam)for paper dry strength additives.And the whole research paper separated three parts mentioned below.Firstly,there were three steps for synthesizing sp-g-cpam:1)Preparation of highly substituted phosphate canna starch.The optimal conditions for this production were found as follows,the reaction temperature of 140℃,NaH₂PO₄ dosage of 25%(based on dry starch weight),the reaction time of 3h,urea charge of 7.5%(based on dry starch weight),pH of 6.0.2)Graft copolymerization of acrylamide(AM)with phosphate starch ester(sp-g-pam)applying ammonium ceric sulfate as initiator.And its optimum reaction conditions are:AM charge of 15g,the initiator concentration of 10mmol/L,and the reaction temperature and time of 75℃and 2h,respectively.3)Cationzation of the graft copolymer.And the nearly optimal conditions were:the ratio of carbamoyl and formaldehyde and dimethylamino of 1:1:1.5(mol/mol/mol),the temperature and time of 60℃and 2h,respectively.Secondly,the structures of canna starch,its phosphate starch ester,sp-g-pam and sp-g-cpam were determined by Fourier Transform Infrared Spectroscopy(FT-IR).And it is also proven that this graft copolymerization is successful and the graft copolymer is the target product.Moreover,the products,which were more effective in increasing paper dry strength, were chosen to be under verification tests.And the results were shown that sp-g-cpam has comparatively good effectiveness in strengthening not only dry long-fiber paper sheets but also dry short-fiber ones,and meanwhile it also plays an apparent role in retention and drainage efficacy.Finally,this paper utilized Colloid Titration method in order to measure effluences of different additives' quantities on the pulp Colloid Titration Rate(CTR).Additionally,the functional principle of sp-g-cpam was preliminary researched by Scanning Electric Microsocopy(SEM)determining the surface of paper samples as well as the brink of breaking paper with and without the additives.