Notin Laure, Viton Christophe, David Laurent, Alcouffe Pierre, Rochas Cyrille, Domard Alain
Société EUROPLAK, 740, av. du 8 Mai 1945, 83130 La Garde, France.
Acta Biomater. 2006 Jul;2(4):387-402. doi: 10.1016/j.actbio.2006.03.003. Epub 2006 May 5.
The morphology and mechanical properties of chitosan fibers obtained by gel-spinning are reported. The objectives were both to understand how the microstructure of the fibers could be modified and how the mechanical properties were improved by means of a dry-jet-stretching step. A highly deacetylated chitosan (degree of acetylation=2.7%) from squid-pens, with a high weight-average molecular weight (M(w)=540,000g/mol) was dissolved in an aqueous acetic acid solution, spun using gaseous ammonia as the coagulant, and then directly dried under hot air. A "post-drying" of 1week was necessary to stabilize the fibers in ambient atmosphere. A dry-jet-stretching ratio applied during the monofilament coagulation (maximal value of 4.3) allowed us to increase the density and favor the orientation of chains along the fiber axis. This allowed us to improve the mechanical properties of the fibers (Young's modulus of 82g/denier and tenacity of 2g/denier). The ageing in ambient atmosphere played an important role in the crystalline microstructure in relation to: the kinetics of ammonium acetate hydrolysis, the formation of a weak fraction of the anhydrous allomorph of chitosan, and an increase of the crystallinity index, whereas the Young's modulus was increased and the tenacity was slightly lowered. In addition, gel-jet-stretched or dry-jet-stretched fibers could be stored at least 3months in ambient atmosphere without any significant degradation.
报道了通过凝胶纺丝法制备的壳聚糖纤维的形态和力学性能。目的是了解如何通过干喷拉伸步骤来改变纤维的微观结构以及提高其力学性能。将来自鱿鱼笔的高度脱乙酰化壳聚糖（乙酰化度 = 2.7%），其重均分子量较高（M(w)=540,000g/mol），溶解于乙酸水溶液中，以气态氨作为凝固剂进行纺丝，然后在热空气下直接干燥。需要进行为期1周的“后干燥”以使纤维在环境大气中稳定。在单丝凝固过程中施加的干喷拉伸比（最大值为4.3）使我们能够提高纤维密度并有利于链沿纤维轴的取向。这使得我们能够改善纤维的力学性能（杨氏模量为82g/旦尼尔，强度为2g/旦尼尔）。在环境大气中的老化在晶体微观结构方面发挥了重要作用，这与醋酸铵水解动力学、壳聚糖无水同质多晶型物弱组分的形成以及结晶度指数的增加有关，而杨氏模量增加，强度略有降低。此外，凝胶喷拉伸或干喷拉伸的纤维在环境大气中可储存至少3个月而无任何明显降解。
