【作者】 董政娥；

【导师】 郁崇文；

【作者基本信息】 东华大学 ， 纺织工程， 2014， 博士

【摘要】 亚麻纤维天然古朴、色彩柔和,具有独特的凉爽舒适性,是化学纤维所不具备,其它天然纤维不可比拟的,被誉为“植物纤维中的皇后”。亚麻产品具有“绿色保健”的特点,倍受消费者青睐,是国际市场上最受欢迎的纺织品之一。然而亚麻脱胶技术存在的不足制约了亚麻纺织难以纺高支纱和生产高档产品。尽管粗纱煮漂工艺有助于纺高支纱,但是工业上多采用化学煮练,其产生的环境污染和对纱线性能的损伤,使得生物沤麻、生物脱胶以及生物煮漂工艺的工业化应用显得刻不容缓。但目前有关亚麻粗纱生物煮练多在中性或偏酸性条件下进行,使得其需要联合传统碱煮才能完成煮练任务。因此,为了减少、甚至不用氢氧化钠煮练,行业内尝试将碱性果胶酶用于棉纤维、织物精练和大麻脱胶。针对亚麻粗纱胶质成分及其采用工艺纤维纺纱特性,本文探讨了在碱性条件下进行生物煮练的可能性。在生物煮练工业化进程中,行业中多关注缩短煮练时间、煮练工艺制定及基于纤维残胶率、强度、分裂度等指标的效果评价,对纤维结构和性能演变研究则关注较少。基于此,本文筛选出含果胶酶和木聚糖酶的纤维单胞菌(Cellulomonas sp)DA8菌株,并采用其在碱性条件下处理亚麻粗纱,在探讨最优煮练工艺同时,结合DSC、TGA和TDA热分析技术、气相色谱-质谱技术、X射线小角散射技术和拉曼光谱分析技术对比分析研究了不同煮练后亚麻纤维结构和性能的演变特征。本文的研究结果如下：(1)筛选出碱性脱胶菌株DA8。经形态、生理生化和16SrDNA序列分析,将其分类鉴定为纤维单胞菌(Cellulomonas sp)。酶活测定表明该菌液同时具有果胶酶活力和木聚糖酶活力,并在pH为6.5-9.0,50℃以下酶活较稳定。DA8菌株在碱性条件下对亚麻粗纱煮练表明,纤维强力损伤小(下降14.19%)；扫描电子显微镜对比观察表明,和原纱亚麻纤维以及传统化学处理纤维相比,DA8处理后亚麻纤维表面胶质去除干净且表面光滑。以煮练后亚麻粗纱束纤维强度和分裂度为响应指标,通过正交实验优化了DA8菌液在碱性条件下的煮练工艺：初始pH为9,温度为40℃,浴比为1：15,时间为12h,摇床转速为200rmp。(2)探讨了漂白工序、碱性果胶酶对DA8细菌煮练的辅助作用,并与传统化学煮练和课题组筛选另一株DA10细菌和自提粗酶煮练和煮漂中试进行对比研究。研究表明漂白工艺对细菌煮练纤维强力损伤大概在1.5—1.9%左右,煮练后不进行水洗而直接进行一浴漂白和粗纱直接漂白对纤维强度损伤相对较大；和原纱试样相比,无论是DA8细菌煮练,还是以氢氧化钠为主的化学煮练均会损伤亚麻纤维强度,但和化学煮练相比,DA8细菌煮练中纤维强度损伤较小,且细菌煮漂后强力总体下降约是化学煮漂的58.8%；在碱性果胶酶辅助DA8细菌煮练中,碱性果胶酶与DA8用量比例为15：135时,纤维分裂度和强度均达最高,且JFC、EDTA和Na5P3O10同时添加有助于进一步提高煮练效果；在纤维性能上,自提粗酶→碱煮联合煮练较DA10细菌→碱煮联合煮练占一定优势。(3)对不同煮漂工序后纤维进行热性能分析的同时,进行了热解动力学分析和结晶动力学分析。由热解TGA曲线可知,亚麻粗纱不同煮漂工序后纤维的热解可分为3个过程：初始降解阶段、热解主要阶段和残渣热解阶段,在第三阶段,DA8细菌煮练及其煮漂工艺处理后纤维又分为炭化阶段和二次失重阶段,其他试样则只产生至炭化阶段；亚麻粗纱不同煮练后纤维热解残留质量不同表明生物煮练及其煮漂处理后纤维在热解过程中更加容易生成挥发性物质,而不会继续生成焦炭；TGA、DTA和DTG分析表明不同处理后亚麻纤维各个阶段的起始、拐点温度和终止温度向高温侧轻微移动,且主反应区间也增加；通过DSC曲线获得了不同煮练后纤维相转变温度,其大小顺序为S4>S0>S1>S3>S5>S2,而经工厂传统化学碱煮练-漂白纤维DSC曲线变化较平坦,无法确定其吸热峰和放热峰以及相转变温度；通过Coats和Redfern法求得第二反应阶段下活化能E和反应动力学参数,结果表明煮练处理后亚麻纤维热解第二阶段均可由一级反应过程描述,且拟合结果系数全部在0.99-1之间；DSC曲线计算获得了不同煮练后纤维结晶度的同时,通过Avrami方法计算获得了不同煮练后亚麻纤维结晶动力学基本参数。(4)采用裂解-气相色谱质谱分析了不同煮漂工序以及不同生物煮练后亚麻纤维的裂解产物特征。分析研究表明,不同煮漂工序后亚麻纤维在10℃/min升温速率下升温至570℃时热解共包含37种裂解产物,其中共同裂解产物包括二氧化碳、丙烯、环氧乙烷和呋喃半乳糖酐4种；不同煮漂工序后亚麻纤维的保留时间在16min前出现明显色谱峰,之后没有出现明显的特征峰；不同生物煮练后亚麻纤维裂解产物包括二氧化碳小分子化合物、乙醛类化合物、环氧乙烷和三十二烷杂环化合物以及吡哺戊糖糖类化合物；中试试样中自提粗酶煮漂后亚麻纤维的裂解产物增加较多,其中包括二氧化碳小分子化合物；醛、酮、醇、醚、酸和酯类化合物,醛类包括4-戊烯醛、4-戊烯醛；醇类包括环丁醇、2-己炔-1-醇；酮类包括3,3-二甲基-2-戊酮、羟基丙酮；醚类包括乙基缩水甘油基醚；酸类包括乙酸；杂环类化合物,2,3-二甲基-环氧乙烷、顺-2,3环氧丁烷、环氧丙烷、过氧化氢戊烷基、过氧化氢庚基、过氧化氢二丙基、3,4-戊二烯、1,8-二碘辛烷、过氧化氢戊烷基；阿拉伯糖糖类化合物。(5)采用X射线小角散射分析研究了不同煮练后亚麻纤维的结构演变特征。不同煮练后亚麻纤维X射线小角散射曲线有一个明显的散射峰,散射峰极大值对应的散射矢量q分布在0.6-0.8nm-1之间,其中工厂化学煮练漂白后纤维散射峰极大值对应的散射矢量最小,周期长度也最长；亚麻纤维平均周期长度分布在80-108nm之间,其中直接漂白后粗纱纤维的平均周期长度最低,说明其纤维分离度最差,细菌煮练后两种漂白方案处理纤维的平均周期长度相近,均为87.59nm,而原纱粗纱、化学煮练粗纱、DA8细菌煮练粗纱则相近；亚麻纤维的Guinier曲线在小角处呈上凹状表明煮练后纤维散射体系是密度不均匀体系,不同煮练工序处理后亚麻纤维微原纤形状不同,工厂化学漂白和DA8细菌煮练后微原纤近似于球状,其他方案处理与原纱纤维相同,其微原纤均为旋转椭球状或长棒状；亚麻粗纱煮练后,其Porod均呈正偏离,亚麻粗纱不同煮练工序处理后纤维微原纤截面层厚度分布在0.59-0.64nm之间,不同生物煮练后亚麻纤维微原纤界面层厚度则分布在0.62-0.70nm之间；除工厂酶漂粗纱纤维散射体具有表面分形结构外,其他处理均具有质量分形特征。(6)采用拉曼光谱分析研究了亚麻粗纱不同煮练后纤维结构演变特征。分析表明,亚麻粗纱不同处理后纤维中纤维素的主要特征峰为2897,1121,1098,378cm-1;2897cm-1峰产生于纤维素C-H及CH2的伸缩振动。1121cm-1峰归属于纤维素C-O-C糖苷键的对称伸缩振动和C-O-C环呼吸振动,而1098cm-1是纤维素C-O-C糖苷键的非对称伸缩振动峰。378cm-1归属于纤维素β—-D葡萄糖苷键。生物煮练后,在漂白工艺中0.3-0.4%浓度的NaOH用量即会使得亚麻纤维中纤维素结晶区由纤维纤维素Ⅰ向纤维素Ⅱ发生多晶形转变。采用纤维素拉曼峰强度比值R=I1120/11098表征不同处理后亚麻纤维分子变化程度,R值越大,表明半纤维、果胶等非纤维素碳水化合物和木质素的影响越大。综合分析表明,在碱性条件下进行亚麻粗纱生物煮练是可行的,通过现代分析技术提取、分析和对比不同煮练后纤维结构和性能演变特征,不仅为进一步合理制定生物煮练工艺、成功实现生物煮练工业化提供了数据支持,而且为进一步阐明碱性条件下生物煮练机理,和更好地开发、利用亚麻纤维奠定了较好的基础。更多还原

【Abstract】 Natural flax fiber is known as the Queen of plant fiber. It is quaint, soft, unique cool and comfortable. These properties are not available in chemical fibers and are incomparable for other natural fibers. Flax products have the feature of green health which does consumers a favor, and is one of the most popular in the international textile market. However, technology deficiencies of the flax degumming restrict linen textile spinning high counts yarn and production of high-end products. The processes of roving scouring and bleaching can help spinning high counts yarn, but chemical scouring was multi-used in industrial which produces environmental pollution and damage to the yarn properties. So it is urgent to make bio-retting, bio-degumming and bio-scouring and bleaching process industrial application.Currently the bio-scouring of the flax roving has been done more in neutral or slightly acidic conditions. The alkaline pectinase was used for cotton fiber, fabric scouring and degumming of hemp fibers. For gum composition of flax roving as well as its use of fiber spinning process characteristics, the paper discusses possibilities of the bio-scouring in alkaline conditions. In the industrialization process of the bio-scouring, more attention to shorten the scouring time, scouring process and its effects evaluation about residual gum, strength, splitting and other indicators was paid. But the structure and properties of the fiber is less of a concern. To achieve bio-scouring or biological degumming of the flax roving, an alkalophilic strain containing pectinase and xylanase was screened from the rotten wrack around Zhoushan archipelago sea area and used for flax roving under alkaline conditions. After exploring the optimal scouring process, some novel analysis methods such as thermal analysis technology of DSC, TGA and TDA, gas chromatography-mass spectrometry, X-ray small-angle scattering and Raman spectroscopy were used to discuss the structure and performance characteristics of different flax fibers after different scouring. The conclusions of this study are as follows:(1) An alkalophilic strain was screened from the rotten wrack around Zhoushan archipelago sea area. It was characterized as Cellulomonas sp and named DA8by strain morphology, physiology, biochemistry and the16s rDNA sequences. Enzyme activity showed that the activities of petinase and xylanase were obtained, and are stable under50℃and at pH values in the range of6.5to9.0. The application showed that the strain had a good characteristic of scouring, and less strength loss of flax fiber was14.19%. Scanning electron microscopy (SEM) showed that the gum in the flax fiber was mostly degraded, and the most smooth fiber surface was displayed, compared with fiber untreated and scoured by caustic soda. The fineness and strength of bundle fiber were evaluated and the orthogonal experimental design of bacterial scouring. An optimum processing was obtained:the initial pH is9.0, the scouring temperature is40℃, Liquor ratio is1:15, degum time is12h and the shake speed is200rpm. The effect of initial pH and scouring temperature on the fineness and strength of bundle fiber was higher.(2) The effects of bleaching process, role of alkaline pectinase on bacterial scouring of DA8, DA10bacteria and crude enzyme were analysized and compared. Studies have shown that the fiber strength damage on process of bacteria scouring and bleaching is about1.5-1.9percent, while the fiber strength damage after scouring without washing and directly bleaching and direct roving bleach is relatively large. Compared to the untreated sample, DA8bacteria scouring and sodium hydroxide chemical scouring will damage flax fiber strength. But the fiber strength damage from DA8bacteria scouring is small than that of chemical scouring, and the overall strength of the bacteria scouring and bleaching is a decrease of approximately58.8%of traditional chemical scouring and bleaching.It is concluded that the amount of alkaline pectinase and DA8ratio of15:135, the fiber fineness and strength reached the highest, and that JFC, EDTA and Na5P3O10will improve further the effect of bio-scouring of DA8. The crude enzyme-alkali scouring occupy a certain advantage compared with DA10bacteria-alkali scouring on fiber performance.(3) The analysis such as thermal performance, pyrolysis kinetic and crystallization kinetics was carried out for different fibers after different scouring and bleaching processes. TGA curve indicated pyrolysis of flax roving after different scouring and bleaching processes can be divided into three processes such as the initial degradation phase, the main phase and the residue pyrolysis stage. In the third stage, DA8bacteria scouring and its bleaching is divided into carbonized fiber weight loss phase and the second phase, while other samples occurs only charring. Different residues of flax roving show bio-scouring generated volatiles more easily and will not continue to produce coke during pyrolysis. TGA, DTA and DTG analysis showed initial temperature, peak temperature and final temperature in various stages have a slight move to the higher temperature side and the main reaction zone also increases for different samples. The transition temperature was obtained from DSC curves, and the order of S4> SO> S1> S3> S5> S2was concluded. While the DSC curve of the sample with conventional chemical scouring and bleaching is relatively flat, in which the endothermic peak, exothermic peak and the glass transition temperature can not be determined. The activation energy E and the kinetic parameters were calculated by the method of Coats and Redfern during the second reaction stages. The results show that pyrolysis of flax fibers after different scouring may be represented by a second stage reaction process description, and the fitting coefficients are good in the0.99-1for all samples. The crystallinity of the fiber after scouring was also calculated from DSC curves and the parameters of crystallization kinetics flax fibers after scouring was obtained through different Avrami method.(4) Features on Pyrolysis of flax fibers after scouring treatment were analysized using pyrolysis-gas chromatography mass spectrometry (PG-CMS). The results indicated there are total37kinds of pyrolysis compounds for flax fiber treated with different scouring and bleaching under the rate of10℃/min heating at the temperature of570℃. Wherein there are four kinds of co-pyrolysis products including in carbon dioxide, propylene, ethylene oxide and beta.-D-Glucopyranose. For different processes of scouring and bleaching there are significant peaks before16min of retention times, and there are no obvious characteristic peaks after16min of retention times. While for the flax fibers treated with different bio-scouring small molecule compounds such as carbon dioxide, ethylene oxide and tri-dodecyl heterocyclic compounds and sugar compounds like DL-Arabinose were included in the pyrolysis products. As far as the samples from pilot, the pyrolysis products increase considerably for the flax fibers mentioning the crude enzyme scouring and bleaching, which including small molecules of carbon dioxide, aldehydes, ketones, alcohols, ethers, acids and esters, aldehydes and DL-Arabinose etc..(5) Structural evolution characteristics of flax fibers treated different scouring were discussed by the Small angle X-ray scattering (SAXS). A distinct scattering peak can be observed by SAXS curve for flax fibers treated by different scouring and bleaching. Besides, a meridional peak between q=0.6-0.8nm-1was also observed, possibly for the first time in cellulose fibers, and this has been attributed to a crystalline/non-crystalline repeat distance between80-108nm. It has also been noted that there is considerable change in structure as flax fibers scouring of NaOH and bleaching in industry for its smallest meridional peak value. Thus repeat distant of chemical scouring-bleaching is the longest, while it is the lowest for samples of bleaching. The repeat distance is similar to two bleaching samples of DA8bacteria scouring and both of them is87.59nm. It is similar for that of samples untreated, NaOH cooked and DA8bacteria scoured. The results show that Guinier curve goes in the small concave corners, which indicates the density of scattering system is uneven for flax fiber with different scouring. The microfibrils of similar spherical is observed for two samples of DA8bacterial scouring and traditional chemical scouring and bleaching, while the micro-fibrils of rotated ellipsoidal or long rod are observed for the other samples. The results of Porod showed that there is a positive deviation for all samples untreated and treated. Analysis indicated that the structure of the cellulose micro-fibrils is consistent with cross section thickness of approximately0.59-0.64nm after different scouring and bleaching processes, while the cross section thickness of samples with different scouring are located about0.62-0.70nm. In addition to the sample of scouring with crude enzymatic and bleaching in pilot the surface of the scattering body has a fractal structure, other treatments have mass fractal characteristics.(6) The structure evolution characteristics of flax fiber after different scouring were studied by Raman spectroscopy. The results showed that the principal peaks of cellulose for treated flax fiber with different roving methods are2897,1121,1098,378cm-1respectively. The intensitive Raman line (2897cm-1) in the range of the CH and CH2stretching vibrations. The Raman line assigned to the vibrational mode Vs(C-O-C) of the fiber cellulose at1121cm-1, while the Raman lines at1098cm-1assigned to the skeletal vibrational modes Vs(C-O-C) and Vas(C-O-C)of the β(1→4) glycosidic linkages of the P-D-glucopyranosyl units of cellulose can serve as characteristic marker bands for multi-component systems like flax fiber. The Raman lines at378cm-1assigned to the β-D-glucopyranosyl units of cellulose. Two Raman lines of cellulose have been used to calculate the intensity rations R=I1120/I1098which had turned out as a sensitive response to molecular changes of flax fibers treated with different scouring. Bleaching of bio-scoured flax fibers in0.3-0.4%of alkali concentrations causes the polymorphic transformation of cellulose Ⅰ into cellulose Ⅱ.In conclusion, it is feasible that the bioscouring was carried out under alkaline conditons for flax roving. It is helpful to extract, analyze and compare the caracteristics on the evolution of the structure and performance after different scourings by modern analytical techniques. And it can provide data support for further developing process, industrialization and mechanisms discussing of bioscouring.更多还原