High-strength alginate fibers wet-spun from pre-crosslinked sodium alginate solutions
Jixiao Hao, Shuai Yan, Hua Yuan, Cong Du, Yeqiang Tan
Abstract
Facing the severe problem of microplastic pollution, there is an urgent need to develop biodegradable fibers to replace the petrochemical fibers. Sodium alginate , a biomass polysaccharide , has gained widespread attentions recently for the fiber manufacture. However, the limited mechanical strength of alginate fibers restricts their usages as load-bearing fabrics and reinforcement fibers . Here, we develop a novel strategy to prepare alginate multifilaments using pre-crosslinked sodium alginate solutions. The increase in the pre-crosslinking ratio effectively hinders the disentanglement of sodium alginate chains at high stretches, causing an increase in the shear viscosity of the solution ascertained from the capillarity-driven thinning process from 4.5 Pa·s to 9.9 Pa·s and facilitating the high alignment and orientation of sodium alginate chains. The resultant fibers possess a breaking strength of 474 MPa, elongation at break of 16 %, Young's modulus of 14.4 GPa, and toughness of 51.8 MJ/m 3 , exceeding most biomass fibers without reinforcement additives. The high orientation degree of 0.865 and high spinnability of alginate multifilaments enable their applications in multi-channel encryption fabrics that exhibit distinct information under various optical conditions. This rheological regulation of spinning solutions provides a facile yet effective strategy to enhance the mechanical performance and broaden application scenarios of alginate fibers.