大麻纤维高温闪爆联合脱胶技术

研究大麻纤维高温闪爆联合脱胶工艺,讨论高温闪爆联合处理条件对大麻纤维性能及组分分离效果的影响。用FTIR、SEM对联合脱胶后大麻的表面形态结构和化学成分进行分析。研究发现:半纤维素和木质素的含量分别下降了81152 %和86168 % ,纤维素比率明显提高,达到大麻纤维脱胶的目的;工艺中高温蒸煮温度、用碱量、闪爆前处理、闪爆压力及温度,保压时间及闪爆次数等是影响纤维分离的重要因素;高温蒸煮及预浸处理对纤维的溶胀作用有利于闪爆条件的降低     

闪爆处理对大麻纤维的影响

针对大麻纤维手感刚硬,易折皱,染色困难等加工难题,将闪爆技术引入大麻纤维的处理,通过对闪爆处理前后大麻纤维的化学组成、表面结构、力学性能和染色性能的比较,研究闪爆处理工艺对大麻纤维性能的影响。结果表明:闪爆处理有利于大麻纤维果胶、木质素和半纤维素的脱除,特别是果胶的脱除;同时可提高大麻纤维的柔软性,改善其染色性能,但闪爆处理会损伤大麻纤维,使其强度有所降低。     

高温脱胶对大麻纤维成分与结构的影响

研究了大麻纤维高温脱胶技术,讨论了脱胶温度和碱量对大麻纤维成分与结构的影响。用SEM、FT-IR、XRD对大麻纤维高温脱胶前后的表面形态结构、聚集态结构进行了表征。实验结果表明:高温脱胶后大麻纤维中的半纤维素和木质素含量分别下降了79.1%和83.5%,纤维素含量提高;大麻纤维的结晶度上升,其结晶度与NaOH的质量分数及反应温度有关。     

苎麻纤维闪爆处理及性能研究

利用闪爆法对苎麻纤维进行脱胶处理,并测试苎麻纤维闪爆处理前后的化学成分、结晶度、力学性能、吸湿性、保水性及热学性能,分析闪爆处理分离苎麻纤维的可行性。结果表明,闪爆处理可以大幅降低苎麻纤维内部的木质素与胶质等,并能提高苎麻纤维的纤维素含量、结晶度及热学性能,但受闪爆机械冲击影响,苎麻纤维的力学性能、吸湿性与保水性有所下降。此外,在相同保压时间条件下,分次闪爆的效果优于一次闪爆。该研究证明可以利用分次闪爆法去除苎麻纤维内部的木质素、胶质等以及提高纤维分离度,为苎麻纤维的开发利用提供了一种洁净工艺。     

稳压时间对大麻韧皮纤维闪爆脱胶效果的影响

为提高大麻纤维的脱胶效果,采用先进的闪爆脱胶技术,对大麻韧皮纤维进行闪爆脱胶实验。针对大麻韧皮纤维在闪爆脱胶过程中,稳压时间对纤维分裂度的提高,对果胶、半纤维素、木质素的去除效果进行了研究与探讨。实验结果表明:适当延长稳压时间,对提高大麻纤维的分裂度,降低大麻纤维中果胶、半纤维素、木质素的含量等都有较为明显的效果。     

闪爆处理后大麻纤维脱胶工艺的研究

对闪爆处理后大麻进行化学处理，采用正交实验分析温度、时间、助剂对纤维失重率和分裂度的影响，得出化学处理过程中的最优工艺配比，并测定各工艺下的大麻纤维长度分布，为生产实践提供参考依据。     

蒸煮温度与碱用量对大麻纤维晶体结构与热性能的影响

研究了大麻纤维高温脱胶技术,讨论了不同蒸煮温度和碱量处理对大麻纤维晶体结构及热稳定性能的影响.用XRD和TG技术对高温脱胶后的大麻纤维晶体结构和热稳定性能进行了表征.试验结果表明:高温蒸煮处理提高了大麻纤维的结晶度、结晶指数和热稳定性,其结晶度、结晶指数和热稳定性与NaOH的用量及反应温度有关;大麻纤维的热稳定性与纤维的晶体结构有关;其最大速率分解温度的升高可能是受纤维素晶体中更高次序的纤维素结构、晶粒尺寸变大和分子链堆砌紧密程度提高所致.     

柔软整理对大麻纤维性能的影响

 为提高大麻纤维的柔软性、可纺性能,针对不同脱胶工艺处理后的大麻纤维在分梳前进行柔软整理。分析柔软整理前后大麻纤维经分梳后的物理机械性能。结果表明：柔软整理后大麻纤维的断裂强度及断裂伸长率均有不同幅度的提高,而且当脱胶程度较低时,柔软整理后大麻纤维的断裂强度与伸长率提高幅度较大;柔软整理后的大麻纤维比整理前的抗弯刚度、摩擦因数均有不同幅度的降低,而且当脱胶程度较低时,柔软整理后大麻纤维的摩擦因数降低的幅度较小;柔软整理后,大麻纤维的回潮率比柔软前均有不同幅度的提高,脱胶程度较低时大麻纤维柔软整理的作用较明显。说明柔软整理有助于改善大麻纤维的可纺性能。     

纺织服装用大麻研究现状

从大麻纤维性能、纱线成纱技术、织物开发与性能研究几个方面,综合阐述国内外纺织服装用大麻的研究成果与发展现状。结果表明:大麻纤维具有较苎麻、亚麻更高的强度,其果胶和木质素含量较高,主要采用化学脱胶工艺;国内大麻纺纱技术目前以湿法纺和干法纺为主,但为了提高大麻纤维利用率、改善成纱性能,常采取干湿并举的工艺;大麻纤维织物包括纯大麻、大麻+棉混纺、大麻+羊毛混纺等类别,其中大麻针织物具有优异的湿传递性能,独特的组织结构有利于散热散湿,适合制作夏季服装面料。目前对于大麻纤维的研究与其他天然纤维素纤维相比还不够成熟,尤其是对大麻混纺织物服用性能的研究比较少(如刺痒感、防护功能等),需要进一步研究探讨。     

液氨处理对大麻纤维结构与性能的影响

针对大麻纤维刚性大,延伸性差,纤维硬而脆,在外力作用下易产生永久变形等问题,采用液氨处理来改善其理化性能。研究液氨处理对大麻纤维理化性能的影响,并对实验结果进行分析,结果表明:大麻纤维经过液氨处理后,纤维密度由处理前的1.537 7 g/cm3下降为处理后的1.531 9 g/cm3;压缩率和压缩弹性率得到提高;静摩擦因数和动摩擦因数有所减小;液氨处理对大麻纤维的束纤维强力影响不大,但使其染色性能得到改善。     

剑麻纤维爆破法制浆和抄造性能的研究

本文采用蒸汽爆破制浆的方法，对剑麻原料进行制浆的研究。制得了得率高、强度好的剑麻爆破浆。分析了剑麻在蒸汽爆破前后纤维形态的变化，并对剑麻的爆破浆及其化学浆的抄造性能进行了比较。结果表明，爆破法剑麻浆是一种良好的造纸原料。     

大麻纤维在氯化锂/N,N-二甲基乙酰胺溶解体系中的溶解特性

为提高大麻纤维溶解性能,对大麻纤维进行氢氧化钠预处理和氯化锂/N,N-二甲基乙酰胺（LiCl/DMAc）溶解处理。用质量分数为18%的氢氧化钠在60℃处理大麻纤维1～4h,然后将预处理后的大麻纤维在不同温度（70、80、95℃）下溶解于质量分数为10％的LiCl/DMAc溶解体系。用扫描电镜、红外光谱仪 和 X 射线衍射仪对溶解前后的大麻纤维进行表征,测试溶解后溶液黏度值。结果表明：氢氧化钠预处理后纤维素的晶型由纤维素Ⅰ转变为纤维素Ⅱ;溶解温度升高,大麻纤维溶解性增强,95℃条件下,预处理2h和3h的大麻纤维在10%LiCl/DMAc溶解体系中能够完全溶解,溶解质量分别为1.0～1.2g和1.2～1.5g;预处理3h的大麻纤维/LiCl/DMAc溶液黏度值更大,溶液稳定。     

预处理方法对丝瓜络纤维性能的影响

为提高丝瓜络纤维资源的利用价值,采用气爆法、复合酶法、化学法对丝瓜络纤维进行处理,研究处理方法对纤维性能的影响。借助扫描电子显微镜、热重分析仪等对处理前后丝瓜络纤维的表面形态、脱胶率、化学成分、热学性能及吸湿性能进行分析,并根据纤维的吸放湿性能绘制吸放湿曲线。结果表明：预处理后丝瓜络纤维表面均出现条痕,化学处理的效果最明显;气爆处理纤维的脱胶率最低为20. 00%,纤维素含量为54. 61%,化学处理后纤维素含量高达81. 10%,酶处理效果介于二者之间,3 种处理方法对木质素的去除率均较低：丝瓜络纤维的回潮率随着脱胶率的提高而增加,3 种方法处理丝瓜络纤维后的吸放湿曲线规律基本一致;预处理有助于丝瓜络纤维热稳定性的提高,且脱胶率越高,热分解温度也越高。     

基于闪爆-碱煮联合工艺的天然竹纤维提取

为了提高对天然竹纤维的脱胶效果,本文研究了天然竹纤维闪爆-碱煮联合脱胶工艺,讨论了闪爆-碱煮联合处理条件对纤维脱胶效果的影响。用FTIR、SEM、强力仪对联合脱胶后竹纤维的化学成分、表面形态结构、强度进行分析。结果表明：闪爆-碱煮联合处理竹纤维的脱胶效果比单一碱煮或闪爆处理的效果好,纤维直径显著减小;闪爆条件越强烈,纤维脱胶率越高,纤维越分散,柔软性越好;竹纤维中半纤维素和木质素也得到了较好的脱除,纤维素含量达到63.59%;纤维断裂强度为21.98 cN/tex,断裂伸长率为3.56%。     

热处理对汉麻乳稳定性的影响及蛋白结构表征

为研究热处理对汉麻乳稳定性及其蛋白结构的影响,本实验通过汉麻乳氮溶解指数、离心沉淀率、乳化特性、乳液表面电位和粒径等指标监测汉麻乳热处理过程中稳定性的变化,利用傅里叶变换红外光谱表征热处理对汉麻乳蛋白二级结构的影响。结果表明：随着热处理温度的升高（55～95 ℃）,汉麻乳氮溶解指数由58.55%逐渐减小到39.81%,离心沉淀率由16.58%逐渐增加到34%,汉麻乳蛋白的平均粒径由192.2 nm逐渐增大到304.6 nm;傅里叶变换红外光谱分析结果显示,随着热处理温度的升高,汉麻乳蛋白分子二级结构发生变化,α-螺旋结构相对含量由28.57%减少到23.70%,无规卷曲结构的相对含量由21.13%增加至25.41%;汉麻乳在65 ℃热处理时,Zeta电位绝对值达到最大（20.57 mV）,此时汉麻乳表现最稳定,乳化活性及乳化稳定性最高,乳化活性指数为0.357 m2/g、乳化稳定性指数为43.74%。本研究结果将为汉麻乳加工及应用提供理论依据。     

Effect of steam explosion on the morphological,textural, and compositional characteristics of betel nut

To reduce the adverse physical effects on the oral mucosa caused by excessive hardness of betel nut fibers, steam explosion was used to soften betel nuts. The effect of three operating parameters (pressure holding time, explosion pressure, and initial moisture content) on the morphology, texture, and chemical composition of the betel nuts was investigated. The fiber hardness and Shore hardness decreased by 56.17%–89.28% and 7.03%–34.29%, respectively, and the transverse tensile strength and fiber tensile strength also decreased by up to 60.72% and 24.62%, respectively. Moreover, the coefficient of static friction and moisture content increased. After steam explosion, the betel nut increased in transverse diameter, became darker and more yellow–red in color, and showed a damaged microstructure. The contents of free phenol and alkaloids decreased after steam explosion treatment, with free phenols and total alkaloids decreasing from 34.32 mg(GAE)/g and 7.84 mg/g to 21.58 mg(GAE)/g and 6.50 mg/g, respectively, after the A-50 s treatment condition. The steam explosion increased the quantity of phenols, alkaloids, and soluble solids released from the betel nut under the same simulated release conditions of the texture analyzer. The research also showed that increased pressure holding time and explosion pressure enhanced the explosion efficiency, while the initial moisture content was reduced the explosion efficiency. Therefore, steam explosion is an effective pretreatment approach to soften betel nut and facilitate healthy development of the betel nut industry.     

Comparison of the performance of kenaf fiber using different reagents presoak combined with steam explosion treatment

To enhance the degumming effect of steam explosion on kenaf fiber, different chemical reagents including hydrogen peroxide (H₂O₂), sulfuric acid (H₂SO₄), and sodium hydroxide (NaOH) presoak combined with steam explosion were used and compared in this article. Distilled water coupled with steam explosion treatment and kenaf raw samples were used as control. The fiber morphology, chemical composition, crystalline structure, degree of fineness, and breaking tenacity of kenaf fibers after treatment were studied. The results showed that hydrogen peroxide (H₂O₂) performs better on removing lignin. It not only splits fibers, but also keeps the fiber’s tenacity during steam explosion treatment. Dilute sulfuric acid (H₂SO₄) performs better on hemicellulose removal, but it damages the fiber cellulose during steam explosion treatment and cause the fiber strength decrease a lot. Sodium hydroxide (NaOH) performs the best on removing hemicellulose and lignin, and splits fiber well. However, the breaking tenacity of the fiber is lower than the fiber pretreated by H₂O₂. Besides, NaOH is a pollutant to the environment. In conclusion, H₂O₂ could be considered as the most promising reagent to be used in combined presoak-steam explosion system.     

Effects of steam explosion on the characteristics of windmill palm fiber and its application to fiberboard

Windmill palm fiber (WPF) obtained from the leaf sheath was treated by steam explosion under the pressure of 2.0 MPa for 120 s to modify and improve the properties of the panels manufactured with it. For comparison, an alkali treatment and acid treatment have also been used to treat WPF. Fiber analysis, scanning electron microscopy (SEM) observation, Fourier transform infrared spectroscopy (FTIR) and chemical composition analysis showed that after the steam explosion treatment: (1) the length, width and fine elements of the windmill palm fibrils were more influenced by the steam explosion treatment than by the other two treatments. (2) A great number of spinulose spherical silica bodies and waxy layers were observed on the surfaces of all the fibers except for the steam explosion treated windmill palm fiber (SEWPF) surfaces, and (3) the cellulose fraction correspondingly increased with the decrease of the hemicelluloses and lignin contents. Finally, the SEWPFs were used to produce fiberboards, and the modulus of rupture (MOR), internal bond (IB), water absorption (WA) and thickness swell (TS) of the fiberboards were measured. The results showed that the WA and TS of the fiberboards made of SEWPF decreased 22 and 32%, respectively, in relation to those made of WPF, whereas the IB increased 46%. It is suggested that steam explosion can be a feasible approach to modify WPF and expand its uses.