Plasticizing Effectiveness and Characteristics of Different Mono‐Alcohols, Di‐Alcohols, and Polyols for Starch‐Based Materials

Abstract

AbstractThe effectiveness of various alcohols as plasticizers for starch‐based materials is studied. Specifically, the impact of molecular structures, such as the number of hydroxyl groups, molecular weights, and chemical structures of these compounds, on the performance of starch‐based films is studied. Several alcohols are used, including mono‐alcohols (propanol, butanol, pentanol, and hexanol), di‐alcohols (ethylene glycol, propanediol, butanediol, and pentanediol), and polyols (glycerol, erythritol, xylitol, sorbitol). Tensile testing and DSC, TGA, DMA, XRD, and SEM characterization of the starch film are used to assess plasticizing effectiveness. Alcohols with a low number of ─OH groups, such as mono‐alcohols, are not retained in the starch matrix because their compatibility with starch is low. The presence of a long alkyl chain in the alcohol reduces compatibility with the starch matrix even more. This type of material has low or no plasticizer efficiency. Di‐alcohols are more compatible with starch, especially those with short alkyl chains like ethylene glycol. Polyols with many ─OH groups are more compatible with starch. The effectiveness of these alcohols as starch plasticizers is proportional to the number of ─OH groups present. All alcohols, whether liquid or solid, must facilitate water′s action.