Experimental and modeling studies on the synthesis and properties of higher fatty esters of corn starch.

摘要

A systematic study was conducted on the synthesis of higher fatty esters of corn starch (starch laurate and starch stearate) using the corresponding vinyl esters. The reactions were carried out in DMSO using basic catalysts (Na2HPO4, K2CO3 and Na-acetate). Effects of process variables (vinyl ester to starch ratio, catalyst intake, reaction temp. and type of catalyst) on the degree of substitution (DS) of the starch laurate and starch stearate esters was determined by performing a total of 54 experiments. The results were adequately modeled using a non-linear multivariable regression model (R20.96). Basicity of the catalyst and reaction temp. had the highest impact on product DS. Thermal and mechanical properties of some representative product samples were determined. High-DS products (DS = 2.26-2.39) were totally amorphous whereas low-DS ones (DS = 1.45-1.75) were still partially crystalline. Thermal stability of the esterified products was higher than that of native starch. Mechanical tests showed that the products had a tensile strength (stress at break) between 2.7-3.5 MPa, elongation at break of 3-26%, and modulus of elasticity of 46-113 MPa.