Enhancing Crack and Mold Resistance of Bamboo by In Situ Construction of Shape Memory Epoxy/Poly(furfuryl alcohol) Bioresin

Abstract

Bamboo, attributed to its short growth cycle and excellent mechanical properties, has become a popular alternative to wood and other building materials such as cement and steel. However, its susceptibility to cracking and molds hinders its broad application in architecture and furniture. In this study, the bioresin polyfurfuryl alcohol (PFA)-modified epoxy resin (EP)/polyetheramine (PEA) system was constructed and in situ cured inside bamboo. Results showed that the epoxy/PFA bioresin could fill in the vascular bundles and parenchyma cells of bamboo, in situ cured and combined with it via hydrogen bond to form a composite with good overall performance. Especially, the epoxy/PFA bioresin possessed good shape memory performance, which was able to counteract the dry shrinkage stress of bamboo. The three cycles of extreme heating–cooling tests and 6 h continuous drying test at 103 °C were conducted to verify the modification effect on crack resistance of bamboo. The PFA/EP/PEA-modified bamboo culms remained crack-free, while 75% of untreated ones cracked in heating–cooling tests. Besides, when all of the untreated bamboo culms cracked, only 33.3% of the PFA/EP/PEA-modified bamboo had cracks in the continuous drying test. Furthermore, the epoxy/PFA bioresin system in bamboo also improved the mold resistance. The bioresin composites comprising bamboo, epoxy, and PFA exhibit considerable potential for advancing the incorporation of bamboo into ecologically sustainable practices within the realms of construction and furniture applications. This advancement extends the lifespan of bamboo products as well as expands their application scope particularly in regions experiencing substantial fluctuations in outdoor humidity.