The mechanical properties and thermal conductivity of bamboo with freeze–thaw treatment

Abstract

The aim of this research was to investigate the effect of freeze–thaw treatment on bamboo with different initial moisture content (water-saturated, air-dried and oven-dried). Bamboo (Phyllostachys pubescens) were treated with two freeze treatments and its microstructure, chemical composition, mechanical properties and thermal conductivity were characterized by field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), mechanical testing machine and thermal conductivity tester, respectively. The results showed that the freeze–thaw treatment had little influence on the microstructure of bamboo, the chemical composition content and the cellulose crystalline structure of bamboo were also not altered. The crystallinity index was found to increase with the increase of initial moisture content. The bending strength and elastic modulus of the treated bamboo increased, the extent of the increase was dependent on the initial moisture content and the freezing temperature. The thermal conductivity of the treated bamboo increased remarkably, which might be possibly determined by the cellulose crystallinity, moisture content, and density of bamboo.