【作者】 赵静娜；

【导师】 潘志娟；

【作者基本信息】 苏州大学 ， 纺织材料与纺织品设计， 2009， 硕士

【摘要】 静电纺丝是一种简单易行的制备纳米纤维的方法,目前采用静电纺丝的方法已经将100多种材料成功地制成了微米或纳米级纤维,目前关于静电纺方面的研究多数是无纺纤维毡,也有一些关于定向排列的静电纺纤维的研究,但是静电纺连续纱线的研究较少。在能源危机日益严峻、人们环保意识日益增强的今天,可降解材料(尤其是天然可降解材料)已经成为了研究的热点。蜘蛛丝是自然界强度最高的蛋白质纤维之一,有其它天然纤维和合成纤维无法比拟的综合力学性能,PLA和蜘蛛丝都有良好的生物可降解性和生物相容性,非常适合做人造肌腱、人造器官、组织工程支架材料、组织修复材料以及手术缝合线等生物医用材料。本文以聚乳酸和蜘蛛丝作为原料采用静电纺丝的方法制备得到连续的纳米级纤维纱。主要从纱线的静电纺丝工艺、后处理以及降解性和生物相容性等几个方面入手,进行了以下几方面的研究:静电纺丝工艺:以蜘蛛丝/六氟异丙醇(HFIP)和聚乳酸/HFIP的混合液为纺丝液,讨论了9wt%PLLA溶液和1wt%蜘蛛丝蛋白溶液质量混合比、纺丝温度、卷绕速度、纺丝液流量和纺丝电压对纱线内纤维的排列、纱线的形态结构和力学性能、以及纺丝稳定性的影响。综合各方面因素最后确定的优化纺丝工艺为:混合比为7:3,纺丝温度为150℃,纺丝电压14kv,纺丝液流量4ml/h,纺丝高度9cm,卷绕速度105±5rpm。在此工艺下,纱线的可纺性较好,纺丝稳定性也很好,纤维定向排列的程度较高,并且纱线在水中的稳定性很好。但这种初生纱的强度较低伸长偏大,需要对其进行后加工处理。后加工:讨论了加捻和后拉伸对蜘蛛丝/聚乳酸复合纳米级纤维纱的结构、力学性能及结晶结构的影响。加捻使原本松散的纱线抱合紧密,大大提高了纱线的力学性能,单股纱加捻2250T/m时强度可提高36.98%,双股纱加捻后纱线强度的提高更明显,1500T/m时强度提高了29.97%。热拉伸对初纺纱的作用非常显著。随着拉伸倍数的增加,纤维直径和纱线细度减小,断裂伸长呈下降趋势,断裂强度和初始模量明显提高。拉伸1.6倍时纱线强度提高了70%。但是拉伸倍数过大会造成纱线强度下降。热拉伸还改善了纤维的结晶结构,纤维的结晶度提高。生物降解性和细胞相容性:研究了蜘蛛丝/聚乳酸复合纳米级纤维纱的在磷酸缓冲液和放线菌酶降解液中的降解性能。结果表明,纱线在这两种溶液中的降解都很不明显,在磷酸缓冲液中降解90天后的SEM图上仍然看不到明显的纤维破碎痕迹,纱线失重率和强度损失率也都很小;在放线菌酶溶液中的降解也不明显,纱线失重率和强度损失率相对于磷酸缓冲液稍大,降解5周之后强度损失了15.28%。静电纺蜘蛛丝/PLLA混合纤维毡与成纤维细胞间具有良好的相容性,细胞在其表面的成活率很高,蜘蛛丝蛋白的加入增加了材料与细胞间的相容性,细胞活性的大小次序为:蜘蛛丝/PLLA混合纤维毡>纯PLLA>空白板。更多还原

【Abstract】 Electrospinning is a simple and cost-effective way to get fibers in micro- and nano-meters, currently, more than one hundred kinds of materials have been eletrospun into micro- and nano-meters fibers. Most of the published reports are about randomly nonwoven mat as far as today, some are about well-aligned electrospinning nanofibers, however, there were only several researches referring to continuous fibers bundles.Especially, the energy crisis has become more and more vital in today’s world, and the sence of environment protection has been enhanced globally, biodegradable materials, particularly native biodegradable materials attracts worldspread attentions. In which, spider is one of the strongest known natural materials with high tensile strength and toughness, having very superior mechanical properties, other more, Polylactic acid (PLA) is the most promising one. Both PLA and spider silk are perfect biomaterials due to their biodegradability and biocompatibility, with the potential applications of artificial tendon, organism, tissue engineering scaffolds, wound dressing materials, sutures and so forth.In this paper, Spider silk and PLA was used as raw materials, continuous nanofibers’bundles was achieved by electrospinning. The main contents of this paper include the effects of electrospinning process parameters, post-twisting and post-drawing on the filament, and then their biodegradability and biocompatibility, the details are as follow: Investigation on a technique for electrospinning continuous filaments constructed of nano-scale fiber bundles: spider protein (Ornithoctonus huwenna spider silk) and PLA mixed solution was used as electrtospinning solution, five factors were taken into account in our experimental process, including PLLA / spidroin solution mass proportion, reeling temperature, solution flow rate, rotating speed, voltages, besides, the continuous electropsinning time was another important element, finally, we get the optimized electrospinning parameters: mass ration of 9wt% PLLA and 1wt% spidroin solution 7:3, solution flow rate 4ml/h, reeling temperature 150℃, voltage 14kv, and winding speed 105±5rpm. In these conditions, the yarn goes smoothly and steadily, the inter-fibers shows a high degree of arrengment, the boundle shows no shrinkage in water, however, has a low stress and high strain, the mechnical properties need to be improved.Effect of the post-twisting and post-drawn on the structure and properties of the fiber bundles: we investigated the effect of post-twisting and post-drawing on the morphology, mechnical properties and crystalline structure of nanofiber bundles. Twisting made the loose bundle compact, the stress between individual fibers re inforced, the mechanical properties was also improved, single filament increased by 36.98% at 2250T/m and double filament increased by 29.97% at 1500 T/m.Post-drawing had an obvious effect on the as-spun bundles, with the increasing of the drawing ratio, fiber diameter and the liner destiny of the filament decreased, and stress at break and initial modulus increased by 70% and 93% respectively at a drawing ratio of 1.6, besides, heat-drawing can improve the crystalline structure, make a higher crystalline degree.The biodegradability and biocompatibility of the nano-scale fiber bundles: the biodegradability in phosphate buffer solution and actinomyces enzyme biodegradable fluid was studied respectively. The results didn’t show obvious effect, there was no clear degradable signal in the SEM image, after 90 days in phosphate buffer solution, only slight weight lose and stress lose could be observed, which was a little obvious when using actinomyces enzyme biodegradable fluid, with 15.28% stress lose after 5weeks.MTT method was used to investigate the cell biocompatibility of the electrospun filament, the result showed a good compatibility with big rat fibroblasts, also, the addition of spider protein enhanced the compatibility between cell and matrix material, cell activity degree: spider protein fiber mat>pure PLLA fiber mat>blank templet更多还原