Preparation and characteristics of foamed bamboo shell/starch composite

In order to reduce environment pollution from waste bamboo shoot shell, starch/bamboo shoot shell foam composites were synthesized by baking method from the mixture of bamboo shell and corn starch. Response surface analysis was conducted by using software Design Expert Version 7.0.0 to optimize the foaming parameters, and the foam composites were characterized and analyzed with Fourier transform infrared spectroscopy, scanning electron microscope. The results showed that the interaction effects among NaOH solution mass fraction, 2,2′-Azobis (2-methylpropionitrile) and Na2B4O7·10H2O dosage on the density of foam composites were significant. With bamboo shoot shell powder of 5 g, corn starch of 2.5 g, foaming temperature of 66℃ and foaming time of 10 h, the optimized condition was as following: NaOH mass fraction 9.8%, 2,2′-Azobis(2-methylpropionitrile) 1.4 g and Na2B4O7·10H2O 0.26 g. At above condition, the holes with thin wall in foam composites were fine and uniform, and most holes were circle or similar. The coordinate linkage reaction occurred between bamboo shoot shell fiber and starch through Na2B4O7·10H2O besides the hydrogen bonds. The results can provide references for improving the properties of starch foamed material and comprehensive utilization for the bamboo industry resources.