Study On Starch Based Green Absorption Material

Hydrophobic micro-porous waxy corn starch was prepared by using waxy corn starch as material, enzymolysis reagent of compound enzyme being composed of a-amylase and glucoamylase, hexamethyl disilazane(HMDS) as hydrophobic modification reagent in this paper. The enzymolysis conditions of waxy corn starch, and hydrophobic modification reaction conditions of waxy corn starch, relation of micro-porous size to making pore conditions, thermal performance and physical property of micro-porous waxy corn starch and hydrophobic micro-porous waxy corn starch were discussed. The results were showed that the pore formation of waxy corn starch was influenced by amount of compound enzyme, ratio of a-amylase to glucoamylase, enzymolysis pH, enzymolysis temperature and enzymolysis time. The better technology conditions of preparing micro-porous waxy corn starch are mass ratio ofα-amylase to glucoamylase 1:3. concentration of starch 25%, enzymolysis temperature 55℃, enzymolysis time 12h enzymolysis pH 5.0, amount of compound enzyme 1.5% respectively.The hydrophobic of micro-porous waxy corn starch related to reaction time. reaction temperature, pH and amount of the hydrophobic agent. The better technology conditions for preparing hydrophobic micro-porous waxy corn starch are reaction time 4h, reaction temperature 55℃, pH 9.0 and amount of the hydrophobic agent 10%.Compared with the native starch, the volume rate, oil absorption rate, separated water percentage, transmittance, swelling volume and viscosity stability of micro-porous waxy corn starch increased, but its sedimentation volume decreased. The separated water percentage and sedimentation volume of hydrophobic micro-porous waxy corn starch was less than that of micro-porous waxy corn starch. But its viscosity stability, transmittance and swelling volume more than that of micro-porous waxy corn starch.The different pore structures of micro-porous waxy corn starch were obviously seen by SEM. Many holes and the structure of the ring layer shape owing to the holes being destroyed on the starch particles were observed after the waxy corn starch was hydrolyzed by two enzymes. It was showed by XRD,TGA and DSC that the crystallization degree and thermal stability of the micro-porous waxy corn starch increased after waxy corn starch being hydrolyzed by the compound enzyme. hydrophobic modification could result in the increase of oil absorption rate of micro-porous waxy corn starch. Hydrophobic group make the hydroxyl group number of the micro-porous waxy corn starch reduce by infrared spectroscopic analysis.