Modified Corn Starches with Improved Comprehensive Properties for Preparing Thermoplastics

Abstract A novel method of starch modification was developed to obtain thermoplastic starch plastics with improved comprehensive properties. Corn starch was oxidized under mild conditions using sodium periodate to prepare dialdehyde starch, which had an acceptable average molecular weight. The dialdehyde starch with 35.2% carbonyl content was reacted with different alcohols (methanol, ethanol, and glycol) to prepare a series of novel starch derivatives, whose structures were characterized by 1 H‐NMR and FT‐IR. The thermogravimetric analysis showed that these starch derivatives had an improved thermal stability compared with dialdehyde starch. Thermoplastic starch and its derivatives were prepared when water and glycerol were added as plasticizers. The modified thermoplastic starch and its derivatives had better mechanical properties than other modified starches, and lower humidity absorption than conventional thermoplastic starches. The highest tensile strength and elongation at break reached 17.5 MPa and 149%, respectively, and the highest humidity absorption was about 37%.

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