| With the decreasing of petroleum resource, how to develop and apply starch resources form depth and breadth has become a common concern of home and abroad scholars. It's widely attention for starch with its merit of extensive sources, low price, strong regrowth habits, less pollution to our environment and so on. Duo to hemicrystalline of native starch, with highly regular crystalline regions, water and chemical reagents could not easily enter into the inner crystalline regions because of this unique structure, which results in a high gelatinizing temperature, poor chemical reactivity of starch. Therefore, there has become an important research tasks on how to pretreatment the starch to decrease the structure in the crystalline region to improve the chemical reactivity of starch.In this thesis, maize starch was first mechanical activated by a high-energy stirring-type ball mill. Then the mechanical activation starch will be used to graft copolymerization reaction. Using potassium persulfate as initiator, styrene as monomer, The effect of mechanical activation time, reaction time, emulsifier concentration, initiator concentration, monomer-starch concentration proportion and reaction temperature on graft reaction were investigated by using G and GE as an evaluating parameter. The token of graft production were investigated respectively by using Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffractometry and scanning electron microscopy. The effect of raw material and composite emulsifier ratio on graft latex and its property of dope had been further investigated. The following main conclusions can be drawn on the basis of the experimental results and theoretical analysis.(1) Under the same experimental conditions, the G of graft copolymerization from 77.54,94.52 and 128.79%, the GE of graft copolymerization from 51.13,62.45and 76.35%, the C of graft copolymerization from 75.83,75.67and84.34% for non-activated (gelatinization). activation time 0.5h and activation time 1h of the maize starch . The results showed that the mechanical activation pretreatment obviously enhanced graft reactivity activity of maize starch.(2) The results of FTIR analysis are consistent with the successful grafting of styrene monomers onto starch. The DSC measurements demonstrated that the thermal stability of grafted product improved with the increase of G, and the crystallinity was decreased markedly. The results of XRD and SEM analysis indicate that the crystal structure of maize starch could be destroyed by mechanical activation, and graft reaction not only occurs in amorphous region, but also in the crystalline region. The graft reaction has the notable influence on the crystal structure of starch granule.(3) Under the same experimental conditions, using native maize starch as material, the performance of emulsion does measure up when the mass ratio of starch/styrene/butyl acrylate up to 1:2:1. Using activated maize starch as material, the performance of emulsion does measure up when the mass ratio of starch/styrene/butyl acrylate up to 1.5:2:1, and the solid content of emulsion up to 29.4%. The performance of the best prescription of emulsion up to par of interior wall coating. This emulsion can be used as film-forming substance for interior wall coating.
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