Blending Modification Of The Cross-linking Starch

Starch is readily available inexpensive and biodegradable. In recent years, the research on biodegradable plastic, has become a hot topic. Starch-based foam materials were more highly focused. Previous literatures mostly focused on its chemical foams process, but its physical foam was seldom reported, so the physical cross-linking starch materials was systematically studied in this paper.The corn crosslinking starch,corn starch,oxidized starch, the tapioca crosslinking starch and water are prepared in the physical cross-linking starch. The characteristics of the freeze-drying starch are further studied by the differential scanning calorimeter, X-ray analytical, scanning electeon microscopic, electronic universal testing machine. The result were as follow:The peak temperature of starch is improved by low moisture content water. With the content of starch increasing between corn starch, corn crosslinking starch and tapioca crosslinking starch, the peak temperature and enthalpy first rised and then decreased. The oxidized starch have good flow characteristics,so the peak temperature and enthalpy rised with the increase of starch content.The xrd spectrum of physical cross-linked starch is a dispersion peak pattern after freeze-dried. Microcrystalline structure diffraction peaks is mainly caused by the starch retrogradation. When the physical cross-linking is greater than the steric effect, the number of hydrogen bonding and recrystallization performance is increasing. conversely,the number of hydrogen bonds and recrystallization performance decreased.The corn starch and the tapioca crosslinking starch appeared to have a honeycomb-like structure for the loss of a lot of water during freeze-drying treatment. The corn crosslinking starch and oxidized starch have a rectangle and gully hole structure. Ice formation process is the main factors influencing the surface morphology of material. With the improvement of the high cross-linked starch, the compression strength first increased and then decreased.The cross-linked starch contains phosphodiester bond, enhanced the role of hydrogen bonds.The oxidized starch overcomed the defect of the high concentration of poor flow characteristics and significantly improved mechanics performance.The study results show that starch content, phosphorus oxychloride content, the high cross-linked starch content have effect on compression strength.