Sound absorption, structure and mechanical behavior of konjac glucomannan-based aerogels with addition of gelatin and wheat straw

Abstract

• KGM, gelatin and wheat straw were used to prepare aerogels for sound absorption. • Addition of gelatin contributes to formation of more small open pores. • Multi-cavity structure of wheat straw is beneficial to sound absorption. • Mechanical strength is improved with finer pores, thicker walls and nest structure. • Gelatin and wheat straw addition is considered in modeling of compressive behavior. Environment-friendly konjac glucomannan (KGM)-based aerogels with addition of gelatin and wheat straw are produced by freeze-drying method to have promising sound absorption performance, thermal stability and mechanical property. Results show that gelatin addition can significantly improve sound absorption performance at medium and high frequencies, as well as mechanical strength, because of the positive effect on increase of small open pores. Appropriate little addition of wheat straw can improve the sound absorption property due to the dissipation effect of sound energy by the unique multi-cavity structure. Better sound absorption performance is achieved than melamine foam, while the best result is obtained with a noise reduction coefficient of 0.38, and the coefficient reaches 0.88 at 4500 Hz. Wheat straw addition leads to strength reduction firstly but enhancement when the addition is more than 1.00%, where fine wheat straw bars form nest structures for strengthening. For potential loading capacity evaluation, a mechanical model is proposed and confirmed to be effective in predicting compressive stress – strain relationship of KGM-based aerogels with consideration of gelatin and wheat straw addition.