Heterogeneous reaction kinetics between mono epoxy–terminated polydimethylsiloxane and gelatin: Effect of material ratio and temperature

ABSTRACT

Heterogeneous reaction kinetics between mono epoxy–terminated polydimethylsiloxane (PDMS-E) macromonomer and gelatin was studied. The purpose of this work was to establish the relationship between the reaction conversion rate and the reaction rate, and to confirm the optimization range of the reaction conditions, including material ratio and temperature. The Van Slyke method was used to monitor the reactions by measuring the conversion rate of amino groups in gelatin. The rate constant for the reaction of the amino group was calculated as k. The results showed that k followed the order k_0.8 > k_0.6 > k_0.4 > k_1.0 > k_0.2 when PDMS-E/gelatin material ratios were tuned from 0:1.0 to 1.0:1.0 at an interval of 0.2. The reaction conversion rate of amino groups reached its peak value at the ratio of 0.8:1.0. The temperature-dependent rate constant showed that k followed the order k₅₅ > k₅₀ > k₄₅ > k₄₀, and the reaction conversion rate of amino groups reached its peak value at 50°C. The reaction was accompanied by an increase in the endothermic process and a decrease in entropy.

KEYWORDS:

• Gelatin
• heterogeneous reaction
• kinetics
• material ratio
• mono epoxy–terminated polydimethylsiloxane
• temperature effect