基于蒸汽闪爆预处理的棉秆皮纤维及其PBS复合材料制备

发布时间：2018-07-05 12:50

本文选题：棉秆皮纤维 + 蒸汽闪爆　；参考：《江南大学》2017年硕士论文

【摘要】：棉秆是一种来源广、产量高、能高效再生的生物质能源。但是目前棉秆的利用价值还很低,主要由于其处理工艺以及成本方面受到限制。棉秆皮是附着在棉秆上的一层韧皮纤维,占棉秆重量的26%。棉秆皮主要由纤维素、半纤维素、木质素以及一些果胶、脂蜡质组成。本文着重研究结合蒸汽闪爆和超声波/微波棉秆皮分离棉秆皮纤维,从中提取纤维素等有效成分,制备棉秆皮纤维,并将制备的棉秆皮纤维与聚丁二酸丁二醇酯(PBS)混合制备复合材料。首先,本课题研究了蒸汽闪爆法预处理棉秆皮纤维。主要研究的是,蒸汽闪爆重要工艺参数蒸汽压力(0.8MPa,1.0MPa,1.2MPa,1.4MPa,1.6MPa)和闪爆保压时间(60s,120,180s,240s,360s)对蒸汽闪爆制备的棉杆皮纤维性能(成分、表面形态、力学性能)的影响。结果表明:蒸汽闪爆能有效地使得棉秆皮紧密的结构被打开,使其得到初步分离,同时还能去除棉秆皮中部分的非纤维素类物质。然而,过高或过低的条件均会产生一定的弊端。闪爆压力过低,棉秆皮得不到有效的分离;闪爆压力过高,棉秆皮分离后得到的纤维性能较差,纤维长度短,强力差。蒸汽闪爆的最优工艺为:蒸汽压力,1.2MPa;保压时间,3min。此时,得到的棉秆皮纤维的半纤维素含量为8.8%、长度为66.2mm、细度为48dtex、断裂强度为2.4cN/dtex以及得率为48%。其次,研究了超声波/微波-有机碱联合处理蒸汽闪爆后的棉秆皮纤维。超声波/微波协同处理(Simultaneously ultrasonic wave and microwave assisted treatment,简称SUMAT)是一种新型的强化加工方法,本文采用此方法辅助有机碱四甲基氢氧化铵(tetramethylammonium hydroxide,简称TMAOH)对蒸汽闪爆预处理后的棉秆皮纤维进行后处理,目的是获得性能更好的棉秆皮纤维。本章研究了超声波/微波功率、时间、温度以及有机碱浓度等重要工艺参数对棉秆皮纤维的强度以及长径比的影响。结果表明,棉秆皮经闪爆预处理脂蜡质、果胶和水溶物总量由21%降到6%左右,半纤维素含量由21.8%减少到15.2%,所得纤维细度59 dtex,长径比957,拉伸强度2.15 cN/dtex;SUMAT/TMAOH协同后处理,脂蜡质、果胶和水溶物总量降到1.4%,半纤维素含量减少到9.2%,所得棉秆皮纤维细度34 dtex,长径比1169,拉伸强度2.85 cN/dtex。棉秆皮木质素含量在预处理、后处理前后均没有明显变化。与现有方法相比,本文主要通过去除亲水性半纤维素、果胶、水溶物等,同时保留疏水性木质素而制得高长径比、高断裂强度的棉秆皮纤维。最后,将前期制备的棉秆皮纤维经过梳棉机梳理后,增强聚丁二酸丁二醇酯(PBS)制备复合材料。研究了热压工艺条件对复合材料力学性能的影响以及复合材料的降解性能。结果显示:PBS基质中增强棉秆皮纤维可以在一定程度上提高复合材料的力学性能和热学性能。对复合材料做水降解试验,发现复合材料表面有严重的破损,出现絮状的空洞,内部的棉秆皮纤维发黑,质量减轻。通过对热压工艺的温度、时间、压力以及纤维质量分数做了单因子试验,确定了复合材料热压工艺的最佳条件:压力2MPa、温度140℃、时间20min、纤维质量分数40%。蒸汽闪爆是一种有效的分离木质纤维素的方法,使棉秆皮得到初步的分离和分解,制备棉秆皮纤维。超声波/微波能进一步细化棉秆皮纤维,优化棉秆皮纤维性能。最后制备的复合材料具有生物降解性,可以作为建筑、汽车制造等行业的潜在应用材料。
[Abstract]:Cotton stalk is a kind of biomass energy with a wide source, high yield and high efficiency. However, the utilization value of cotton stalk is still low, mainly due to its processing technology and cost. The cotton stalk is a phloem fiber attached to the cotton stalk, and the 26%. cotton stalk, which accounts for the weight of cotton stalk, is mainly made of cellulose, hemicellulose and lignin. And some pectin, fat wax composition. This paper focuses on the separation of cotton stem skin fibers, such as steam flash explosion and ultrasonic / microwave cotton stalk, to extract cellulose and other effective components from cellulose, and to prepare the cotton stalk skin fibers and polybutylene dibutylene dibutylate (PBS) to prepare composite materials. The main research is the effect of steam explosion (0.8MPa, 1.0MPa, 1.2MPa, 1.4MPa, 1.6MPa) and flash time (60s, 120180s, 240s, 360s) on the fiber properties (composition, surface morphology and mechanical properties) of steam flicker. The results show that the steam explosion can be effective. The close structure of the cotton stalk is opened so that it can be separated initially and the non cellulose material in the cotton stalk skin can be removed. However, the high or low conditions of the cotton stalk can produce some disadvantages. The flicker pressure is too low, the cotton stalk can not be separated effectively; the flicker pressure is too high and the fiber properties of the cotton stalk peel are compared. The optimum technology of steam explosion is: steam pressure, 1.2MPa, pressure holding time, 3min. at this time, the hemicellulose content of cotton stalk skin fiber is 8.8%, the length is 66.2mm, the fineness is 48dtex, the fracture strength is 2.4cN/dtex and the yield is 48%. next, the ultrasonic / microwave organic alkali combined treatment steam flash is studied. The ultrasonic / microwave CO treatment (Simultaneously ultrasonic wave and microwave assisted treatment, for short SUMAT) is a new strengthening processing method. This method is used in this paper to assist the organic alkali four methyl ammonium hydroxide (tetramethylammonium hydroxide, TMAOH) for the pre treatment of steam flicker. In this chapter, the effects of ultrasonic / microwave power, time, temperature and organic alkali concentration on the strength of cotton stalk fiber and the ratio of length to diameter were studied in this chapter. 21% to 6%, hemicellulose content decreased from 21.8% to 15.2%, fiber fineness 59 dtex, length diameter ratio 957, tensile strength 2.15 cN/dtex; SUMAT/TMAOH synergistic treatment, fat wax, pectin and water soluble aggregate decreased to 1.4%, the content of hemicellulose decreased to 9.2%, cotton stalk fiber fineness 34 dtex, length diameter ratio 1169, tensile strength 2.85 cN/dte The content of X. cotton stalk lignin was not changed obviously before and after treatment. Compared with the existing methods, the paper made the cotton stalk skin fiber with high length diameter ratio and high breaking strength by removing hydrophilic hemicellulose, pectin, water soluble and hydrophobic lignin. Finally, the cotton stalk skin fibers prepared in the earlier period were combed. After combing the cotton machine, the composite materials were prepared by reinforced polybutylene dibutylate (PBS). The effects of hot pressing process conditions on the mechanical properties of the composites and the degradation properties of the composites were studied. The results showed that the mechanical and thermal properties of the composites were improved to a certain extent by the enhancement of cotton stalk in the PBS matrix. It was found that the surface of the composite material was seriously damaged, the floc holes appeared, the internal cotton stalk skin fiber was blackened and the quality was reduced. Through the single factor test on the temperature, time, pressure and fiber mass fraction of the hot pressing process, the optimum conditions for the hot pressing of the composite material were determined: pressure 2MPa, temperature at 140. 20min, fiber mass fraction 40%. steam flash explosion is an effective method of separating lignocellulose, which makes cotton stalk peel preliminary separation and decomposition and preparation of cotton stalk skin fiber. Ultrasonic / microwave can further refine cotton stalk skin fiber and optimize the properties of cotton stalk skin fiber. Finally, the composite material has biodegradability and can be used as a construction. The potential application materials of construction, automobile manufacturing and other industries.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS102.22;TB332

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