Thermal Characteristics, Kinetics and Thermodynamics of Thermal Degradation Reaction, and Hydrophobicity of Corn Starch Affected by Chemical and Physical Modifications

Abstract

In this work, glacial‐acetic (A) and citric (C) acids from organic acids “family with one and three functional groups, respectively", oleic acid (O) from the fatty acids family and sodium acetate (S) are used for esterification of corn starch in solution in the absence and the presence of 15%wt glycerin as a physical modifier. Discoloration test using CIELAB and as well as thermal gravimetric analysis shows that the glacial‐acetic acid leads to lower reduction in thermal characteristics of the modified starch. The variations of thermal properties start from T > 112 °C, T>136 °C, T>100 °C, and T> 124 °C for the modified starches with C, A, O, and S reagents, respectively, and the changes are constant beyond the amount of 4%wt reagent. The evaluations of kinetics and thermodynamics of thermal degradation reaction for the modified starches via a Coats–Redfern (CR) model prove that the acetic acid causes more activation energy for degradation compared to other reagents. Also, acetic acid‐modified starch demonstrates the highest hydrophobicity among other modified starches – even native starch – in the moisture sorption examination at 75% relative humidity (RH). The results illustrate that glycerin has the worst effect on the thermal and hydrophobicity properties of the modified starches.

A Comprehensive Study on the Effect of Highly Thermally Conductive Fillers on Improving the Properties of SBR/BR-Filled Nano-Silicon Nitride

“…In the present work, the statistical analysis related to the kinetics of vulcanization reaction of SBR/BR-Si 3 N 4 is performed by using the Python programming language. 45 …”

Catalytic effect of high thermal conductive SiC on the kinetics and thermodynamics of vulcanization reaction of SBR/BR-filled nano-SiC

“…The vulcanization reaction rate during the curing process is defined via the following equation 43 : where dα / dt and dH ( t ) /dt are the vulcanization and heat flow rates, respectively. In general, most vulcanization kinetics are defined via the following equation 44 : where A and E a are the pre-exponential factor and activation energy, respectively.…”

Design of acrylamide-based thermoresponsive copolymer with potential capability for physical network formation in water: a molecular dynamics study

“…In fact, the presented network structure (Figure S1b) needs the CPx chain consisted of a middle and end blocks with the water-compatible and thermoresponsive features, respectively. In the present work, the results of analysis of variance (ANOVA) performed by the Python programming language [48] were used to find the desirable CPx chain structure. The ANOVA provides the analysis of each calculated response in order to evaluate the statistical significance of physicochemical characteristics of the blocks [49].…”