| Starch is abundant and cheap in China. Its graft copolymers with vinylmonomers have excellent properties of the synthetic and natural polymers, such as plasticity and film forming functionality,high-water absorbance, flocculence, adhesive effect and etc. In particular, the renew ability of starch and the biodegradability of the copolymers are beneficial to reduce the load of ambient pollution and the dependence on unrenewable resources. A great deal of attention has been focused on the investigation of the graft copolymers,and the utilization of these substances is becoming more wide-spread. It is the most important for Graft Copolymerization of vinylmonomers onto Starch to choose fit initiators. So normal initiators used for graft polymerization of vinyl monomers on starch are reviewed. The characterization, initiating mechanism and the application of initiators are discussed. This paper reported the graft copolymerization of acrylic acid (AA) onto cassava starch by K2S2O8-NaHSO3 initiators. We found that K2S2O8-NaHSO3 has a hopeful future. Results showed that the condition of reaction was the best when the concentration of AA was 1.2mol/L,the temperature was 35C, the time was 3h,the concentration of the initiator was 3mmol/L and the neutral degree was 80%. The graft copolymerization of acrylic acid onto starch with eerie ammonium nitrate as initiator has been studied. The effects of the reactions parameters, including the amount of inititor and monomer, pH, reaction temperature and time were investigated. The effect of the initiation system was the best when the concentration of AA was 1.2mol/L. the temperature was 50C, the time was 3h,the concentration of the initiator was 3mmol/L and the neutral degree was 80%. Graft polymerization of acrylic acid onto cassava starch using potassium per sulfate-sodium bisulfate as initiators was studied. Five reaction conditions of the graft polymerization are concentration of initiators, reaction temperature, concentration, degrade of neutralization of monomer and reaction times are investigated. We choose different levels of every factor, was chosen to form arthogonal test of five factors and four levels. The result showed that the grafting percentage was higher when concentrations of monomer and initiator were at 1.0mol/L and 3.0mmol/L respectively, the temperature of the reaction was 35 C, the reaction time was 3h, and the neutral degrade was 70%.The graft copolymerization of acrylamide (AM) onto starch initiated by potassium permanganate, potassium persulfate (KPS)- eerie ammonium nitrate was studied. The influence of the concentration of acrylamide and potassium persulfate, temperature and polymerization time on graft percentage and grafting efficiency was investigated. The experimental results showed that both the graft percentage and grafting efficiency were high for initiator of potassium permanganate when the proportion of the acrylmide and the starch was 2, theconcentration of the potassium permanganate was 1.5 mmol/L, the temperature of the reaction was 50 C,the reaction time was 3h, pH degree of the reaction was 2.The result initiated by potassium persulfate (KPS)- eerie ammonium nitrate was better when pH degree of the reaction was 2 to 3,the concentration of potassium persulfate (KPS)- eerie ammonium nitrate was 2 mmol/L, the temperature of the reaction was 50 C,the reaction time was 3h. Then we choose different levels of every factor to form arthogonal test of five factors and four levels. The optimum condition for graft copolymerization was obtained by the experiments when the concentration of the nitric acid was 0.3mol/L,the concentration of potassium persulfate(KPS)- eerie ammonium nitrate was 3.0mmol/L,the proportion of the acrylmide and the starch was 2,the temperature of the reaction was 50X2?the reaction time was 2h. At last, we indicated the figurations of two graft copolymerations using infrared spector and electron microscopy. |
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