Effects of Waterborne Elastic Polyester with Different Compositions on the Properties and Compatibility of Maize Starch

Waterborne elastic polyester (WEP) with different content of hard polyester was applied in the maize starch (MS) based composites (MS/WEP) via solution casting method. The effects of WEP with different contents of hard polyester on the structure and properties of starch were studied by Fourier transform infrared, X-ray diffraction, ultraviolet-visible, tensile test, differential scanning calorimeter, thermogravimetric analysis and moisture measurement. The experimental results show that the addition of WEP does not change the crystalline type of starch, and only reduces the crystallinity of starch. And the structure and properties of MS/WEP are related to not only the content of starch but also the microstructure of WEP or the content of hard polyester in WEP. Waterborne elastic polyester with 30wt% hard polyester (WEP30) has the best modification effect on the maize starch among all the WEPs. For example, MS/WEP30 film has the optimum toughness, aging resistance and transmittance, the lowest crystallinity and glass transition temperature among all the MS/WEP films, and the lower moisture content. It is related to the compatibility between starch and WEP, resulting from the number of physical crosslinking points in WEP.