【作者】 唐志荣；

【导师】 周文龙；

【作者基本信息】 浙江理工大学 ， 纺织工程， 2013， 博士

【摘要】 天然彩色棉是纤维本身具有自然色彩的棉花品种的统称,其颜色呈现是棉纤维细胞在分化和发育过程中色素物质沉积的结果。目前,通过国家审定并大规模种植同时成功应用于纺织品开发的只有绿色和棕色两大品系。天然彩色棉制品具有色泽自然、柔和典雅、质地柔软等特点,用天然彩色棉纤维生产的纺织品无需染色,可降低加工成本,减少污水排放,是名副其实的生态纺织品。但是,目前能纺织应用的天然彩色棉色谱不全、颜色单调、色素不稳定、纤维品质相对较差,这些问题已成为影响彩色棉产业发展的瓶颈。因此,影响天然彩色棉颜色的色素种类和性质,目前已成为研究和开发天然彩色棉产品的关键问题。本文主要研究绿色和棕色两种天然彩色棉纤维色素的提取、分离和组分的结构鉴定,并对绿色棉纤维颜色稳定性的改善及它们的抗菌性能和紫外可见漫反射光谱性能进行了初步探讨。本文首先系统研究了天然绿色棉和棕色棉纤维色素的溶解性能,通过比较分别选用无水乙醇和70%乙醇水溶液为溶剂进行绿色棉和棕色棉纤维色素提取,然后利用初步纯化的色素进行化学性质和光谱分析。结果表明两种天然彩色棉色素类型不同,天然绿色棉色素为极性较弱的碱溶性化合物,含有一种羟基被苷化、并且具有邻二酚羟基的黄酮醇类化合物；天然棕色棉色素为极性较强的水溶性化合物,含有缩合单宁或是缩合单宁氧化而成的苯醌类化合物。针对天然绿色棉色素提取较困难,采用无水乙醇为提取剂,运用正交实验设计方法,探索了天然绿色棉色素在超声波辅助下的最佳萃取工艺条件,并建立一种测定天然绿色棉纤维色素萃取效率的相对定量方法；同时探讨了超声波辅助萃取时不同的工艺条件对色素萃取效率的影响,并与普通浸提效率进行对比分析；文中对天然绿色棉色素的超临界萃取方法也进行了初步探索。研究结果发现：超声波辅助萃取比普通浸提有明显优势,在同等实验条件下,超声辅助萃取20min可达到普通浸提5h的效果,同时,超声波辅助萃取对天然绿色棉色素成分和结构无明显影响。研究表明在超声频率为40KHz、功率为100W时的萃取天然绿色棉色素的最佳工艺条件为：温度70℃,萃取时间100min,料液比为1：125。超临界流体萃取实验发现在压力30MPa、80℃萃取5h,同时加适量夹带剂的条件下可提取部分天然绿色棉色素。在一定的工艺条件下,超临界流体萃取可使天然绿色棉色素向外部转移,增深天然绿色棉纤维表层的颜色。研究获得了一种天然绿色棉色素物质并对结构进行了鉴定。通过对天然绿色棉色素成分用超声波辅助提取法萃取、采用C18反相硅胶柱进行分离纯化,并利用紫外光谱、红外光谱、质谱、核磁共振谱图进行结构表征。研究发现,天然绿色棉色素由多组分组成,其中一种主要组分具有类黄酮化合物的性质,分离干燥后该组分为淡黄色粉末,分子量为592。这种主要组分具有pH依赖性,在碱溶液中颜色随着pH的升高而加深,其颜色变化与碱处理使天然绿色棉纤维的颜色变化规律一致。通过结构鉴定得知,这种主要色素组分可能结构为具有3’,4’-OH、6,7-OH、5-OCH3,并且在6-C上连有葡萄糖基、3-OH被取代的黄酮醇类化合物。分离到的其它两种组分也属于性质类似的黄酮类化合物,其具体分子结构需进一步分离和鉴定。通过对天然棕色棉色素成分萃取,采用聚酰胺柱层析、反相高效液相色谱(RP-HPLC)、制备型液相色谱分离,并利用MADLI-TOF MS和ESI-MS进行分子鉴定,结果表明天然棕色棉色素提取物组分复杂,分子量主要分布在850-1250之间。高效液相色谱反相C18柱可大致将天然棕色棉色素分离,天然棕色棉色素提取液至少含有5种成分,包括4种在反相色谱柱上保留性较差的组分和1簇分子量跨度较大的混合组分。以聚酰胺为吸附剂,依次用蒸馏水、50%丙酮、pH=9.0的氨水和0.3%尿素水溶液为洗脱剂的柱层析体系可有效地将天然棕色棉色素提取液分为4部分。采用反相C18制备柱只能将蒸馏水洗脱部分的组分有效分离,得到了两种有色组分和两种无色组分。分离得到的两种有色成分不属于同一类物质,一种判断为除缩合单宁外的其它酚类化合物,另一种判断为B型缩合单宁的三聚或者更高聚体。分离得到的两种无色成分的结构相似,只相差一个苯环,推测两者可能为含多个芳环的木脂素类物质。针对天然绿色棉色素不稳定,研究获得了一种改善天然绿色棉纤维颜色稳定的新方法。用石油醚预处理天然绿色棉纤维,可提高天然绿色棉色泽的热稳定性和日晒牢度。通过GC-MS研究发现用石油醚预处理可去除天然绿色棉纤维中部分不利于颜色保持稳定的化学成分。石油醚预处理工艺对需高温整理的天然彩色棉产品具有潜在应用价值。发现了天然棕色棉的天然抗菌性。采用改良的AATTCC100-2004《纺织品抗菌性能的定量评估》对经脱脂处理后的天然彩色棉纤维抗菌性能进行定量测定,并用药敏纸片扩散法(抑菌圈法)对天然彩色棉色素进行抑菌实验分析。实验发现经石油醚进行脱脂处理后的天然棕色棉纤维表现出一定的抗菌性能。脱脂处理后的天然深棕色棉对肺炎克雷伯氏菌和金黄色葡萄球菌的抑菌率分别达到96.4%和89.1%；棕色棉颜色越深,抗菌性能越好；而普通白棉与天然绿色棉纤维抑菌效果不明显。天然棕色棉色素类物质影响天然棕色棉的抑菌性能,抑菌圈法测试结果表明天然棕色棉色素具有较好的抑菌效果并且有一定的抑菌耐久性。棕色棉色素在人体汗液环境处理中抑菌性能不变,在高温短时间处理后抑菌能力有所下降,并且处理温度越高,色素的抑菌能力下降越大,但抑菌能力仍有较好地保留。利用天然彩色棉的颜色特性,对两种天然彩色棉纤维的紫外可见漫反射光谱性能进行初步探讨。实验发现天然彩色棉纤维的紫外可见漫反射光谱与染色棉、白棉不同,用紫外可见漫反射光谱法在鉴别天然彩色棉、快速定量测定天然彩色棉与白棉纤维混纺比方面具有潜在应用价值。对本文研究的天然彩色棉与白棉混纺,在450nm波长处具有较好的定量关系,反射率与天然绿色棉含量的关系满足方程y=-14.165Ln(x)+16.3,其R2达到0.9918；反射率与天然棕色棉含量的关系满足方程为y=-14.799Ln(x)+6.0894,其R2达到0.9903。更多还原

【Abstract】 Naturally colored cotton (NCC) is a kind of cotton with natural color in its fiber. Theappearance of fiber color is the result of production and accumulation of the fiber pigment infiber cell. Up to now, only the brown and green NCC fiber can be used in machine spinningtextiles. NCC fibers are of interest in the textile industry because they require little dyeing andresult in less environmental pollution. NCC produces have some excellent properties, such asnatural luster, elegant, soft, and so on. But some of their shortcomings have restricted the furtherdevelopment of NCC industry, such as its monotonous color, poor fiber quality and bad colorstability. Therefore, the type and property of pigment of NCC fiber have become hot issues forthe development of NCC production. The main aim of this paper was to extract, separate andidentify the pigment of green NCC and brown NCC fiber. Also, the improvement of colorchange, the antibacterial performances and UV-visible diffuse reflectance spectral UV-VisDRS properties were analyzed preliminarily.At first, solubility of the pigment in green NCC and brown NCC fiber was researchedsystemically. Absolute ethyl alcohol and70%ethanol aqueous solution were selected as pigmentextraction solvent for green NCC and brown NCC, respectively. According to the chemicalcharacteristics and the wave spectra analysis, pigment types of two kinds NCCs are different.The pigment of green NCC is weaker polarity and alkali-soluble compound, and it may belong toflavonol with two adjacent hydroxide groups and indican replaced a hydroxide group. Thepigment of brown NCC is strong polarity and water-soluble compound, and it may belong tocondensed tannin (CT) or quinine from condensed tannin oxidation.Because of difficult extraction of green NCC pigment, this paper analyzed the optimumextraction process of green NCC pigment with ultrasonic-assisted by using orthogonal testdesign and using absolute ethyl alcohol as extractant, and built a method for the relativequantitative test of pigment in extract liquor of green NCC using an ultravioletspectrophotometer. Comparing with the ordinary extraction, effects of different processconditions with ultrasonic-assisted on pigment extraction efficiency were discussed. In the paper,the supercritical extraction method of green NCC pigment was also explored. The resultsindicated that the pigment composition extracted by ultrasonic-assisted method was as same as that extracted by ordinary extraction, while the extraction efficiency was significantly increased.At the same condition, the efficiency of ultrasonic-assisted extraction of green NCC pigment for20min was equivalent to that of ordinary extraction for5h. By orthogonal experiment, theoptimum extraction technology with ultrasonic frequency40KHz and power100W was:temperature70℃, time100min, solid-liquid ratio1陶奉125ml. At the condition of pressure30MPa,80℃,5h with right amount entainer, the green NCC pigment could be extracted bysupercritical fluid extraction method. In a certain process, supercritical fluid extraction can makegreen NCC pigment to external transfer, and deepen the color of fiber surface.This paper got a kind of pigment material in green NCC and identified its structure. Afterextraction with ultrasonic-assisted, the extracted pigments of green NCC were purified with C18reversed-phase silica gel column, and identified with UV-vis, IR, MS and NMR. Resultsindicated that green NCC pigment is multicomponent. One of the main ingredients was separated,and it has properties of flavonoid compound. After drying, this separated main component islight yellow powder, and molecular weight is592. It has intensive pH value dependence. Inalkali solution, its color darkens with the increase of pH value. This color change is consistentwith the color change rule of green NCC fiber with alkali treatment. Results indicated that thisgreen cotton pigment is a kind of flavonoid also, it has6,7–OH,5–OCH3,6–C–Glu in ring A and3’,4’–OH in ring B, in addition,3–OH is possibly being substituted. Other two separatedcomponents belong to flavonoid compounds also, and their properties are similar. Theirmolecular structure needs to separate and identify in the further.The extracted pigments of brown NCC were purified with polyamide columnchromatography, reverse-phase high-performance liquid chromatography (RP-HPLC) andpreparative liquid chromatography, and identified with UV-vis, MADLI-TOF MS and ESI-MS.Results indicated that there were many ingredients in brown NCC pigment extract, most ofwhich were in the850~1250molecular-weight (MW) region. The pigment extracts of brownNCC could be successfully separated by preparative C18-Reversed-phase chromatography, thepigment extracts consists of five components at least, including four poor reservationscompositions on reverse phase column and one cluster mixture with span bigger MW. Usingdistilled water,50%acetone, pH=9.0ammonia water and0.3%urea solution for elution agent inturn, the pigment extract could be effectively divided into four part fraction by polyamidecolumn chromatography. Two colored and two colorless compositions were isolated from thewater elusion segment by preparative C18-Reversed-phase chromatography. The two colored components didn’t belong to the same kind of substance. One belongs to another phenoliccompound in addition to the CT, the other may be the trimer or tetramer of B type CT. Thestructures of two colorless components were extremely similar. A phenyl was the only difference,and they probably belonged to lignans with multiple aromatic rings.This paper reports a novel treatment method for improving the color stability of green NCC.Pretreatment with petroleum ether can improve color thermal stability and light fastness. Ethanolextracts from green NCC were analyzed by Gas chromatography-mass spectrometry (GC-MS).Results indicated that treatment with petroleum ether can remove certain components which maybe detrimental to the color stability of green NCC. This treatment method is useful for thatneeding high-temperature finishing of green NCC products.The antibacterial property of brown NCC was discovered. The antibacterial activity ofNCCs was evaluated though improved AATCC Test Method100-2004, and the antibacterialperformance of the pigments in NCCs was analyzed with the K-B programe (Inhibition zonemethod). The experiment found that pigments in NCCs influence antibacterial properties ofNCCs. After degreasing process with petroleum ether, brown NCC shows excellent antibacterialproperties with a reduction rate of96.4%and89.1%, when contacting with Klebsiellapeneumoniae and Staphylococcus aureus, respectively. While the antibacterial effect of greenNCC and white cotton were not obvious. The darker was brown NCC, the better wasantibacterial performance. The antibacterial activity of brown NCC is relevant to its pigment.Inhibition zone methods showed that the pigment of brown NCC has good and durableantibacterial ability. The antibacterial effect of the pigment extract in brown NCC shows aninsignificant change under human body sweat conditions. General textile high temperaturecuring conditions will decrease its antibacterial activity, but the antibacterial activity still hassatisfied retention.Finally, using of the color character, UV-Vis DRS properties of NCCs were analyzedpreliminarily. It was found that UV-Vis DRS of NCC is different from dyeing cotton and whitecotton. UV-Vis DRS can identify NCC and rapidly determinate the blended ratio of NCC andwhite cotton fiber. For the investigative NCC and white cotton fiber,450nm wavelength can beused for characteristic wavelength to quantitatively predict. The relationships of reflectivity andgreen NCC content meet the equation: y=尼14.165Ln (x)+16.3, R2reaches0.9918; the relationships of reflectivity and brown NCC content meet the equation: y=尼14.799Ln (x)+6.0894, R~2reaches0.9903.更多还原