Strong and highly flexible slivers prepared from natural bamboo culm using NaOH pretreatment

Abstract

Slivers have been split from fast-growing bamboo to manufacture bamboo weaving products. However, the flexibility and strength of bamboo slivers, especially the bamboo slivers from the inner layer of bamboo, is inadequate for weaving products in various shapes. Herein, we developed a simple method using NaOH pretreatment with various concentrations to process bamboo slivers from natural Moso bamboo (Phyllostachys pubescens) into super-flexible bamboo slivers with improved tensile strength. The changes in the structure and chemical compositions were further indicated to elucidate the strength and toughness strengthening mechanisms behind the alkali treatment. The results showed that the 5% NaOH treatment increased the tensile strength by up to 35 % and 70 % for slivers from the outer- and inner layers of the bamboo culm, respectively. The flexibility of all treated bamboo slivers was significantly improved. The most excellent flexibility of bamboo slivers was found at the 15 % NaOH treatment and this alkali-treated bamboo sliver was able to be violently bent without fracture. The density of 5% NaOH treated sliver from the outer and inner layer of bamboo increased by 14 % and 80.18 % compared with the untreated ones. The parenchyma cells in bamboo slivers collapsed to form in an interlocking structure due to the removal of lignin and hemicellulose, which lead to high strength and flexibility.