Effects of borax and montmorillonite contents on mechanical properties of cassava btarch-based composite hydrogels

Abstract

Starch-based hydrogels possess attractive properties that are potentially advantageous for biomedical applications including biocompatibility, biodegradability, and compliancy. However, the use of the starch-based hydrogel is limited due to its fragility. This problem could be addressed by an addition of reinforcing filler and an increase of crosslinking density. In this work, borax and montmorillonite (MMT) were respectively used as a crosslinking agent and a filler for cassava starch-based composite hydrogels. Effects of borax and MMT contents of on physical properties of cassava starch-based composite hydrogels were investigated. Aqueous solutions of starch at a constant concentration of 15 %w/v was prepared at 95°C. The gelatinized starch solution was then cooled down to room temperature before adding sodium tetraborate decahydrate (borax) at various concentrations (0.05, 0.10, and 0.15 M). Compressive test results showed that compressive modulus and strength of the prepared hydrogels increased with increasing borax content. Also, their gel fraction and water take-up were increased as the crosslink density increased. With MMT addition of various content, compressive modulus and compressive strength of the MMT/starch composite hydrogels decreased while their gel fraction and water take-up capacity were insignificantly changed. This could be because the agglomeration of MMT in the hydrogel matrix.