In this investigation, Carexmeyeriana fiber (CMF) was extracted by using the ultrasound alkali--oxygen technology in the research, and the performance characterization of CMF was revealed. Parameters such as ultrasonic and alkali--oxygen acting times, and the concentrations of NaOH and H2O2 were optimized by using the multi-target orthogonal method. The performance characteristics of CMF were investigated by means of scanning electron microscopy, ultraviolet, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction and other basic testing methods. The result revealed that the optimal parameters in the extraction process were ultrasonic irradiating for 70min, soaking in the alkali--oxygen bath for 100min, and the concentrations of NaOH as 8g/L and H2O2 as 12g/L. After extraction, the characteristic absorb peaks for the non-cellulose of CMF in the FTIR spectra decreased significantly, and the crystallinity increased from 46.5 to 50.6%. Warmth retention and excellent antibacterial properties of the extracted CMF were observed. It was expected that CMF can be developed as a functional fiber in the future.

The physical properties of natural growth fibers such as chemical composition content and fiber diameter are highly affected by environmental issues such as environmental changes and fiber extraction methods. These irregularities of the natural fibers seriously affect its utilization in composite as reinforcements. In this study, taking into account the importance of the fiber tensile strength, the correlation degrees between the kenaf fiber tensile strength and the fiber chemical composition, crystallinity, orientation degree were analyzed by the grey relational analysis method. Both the kenaf single fiber and fiber bundle were used as XRD and tensile strength test sample. The chemical composition content and the FTIR were carried out to obtain a correct result of the chemical composition content. It found that for the different XRD and tensile strength test samples, the single fiber showed lower crystallinity, higher orientation degree and tensile strength compared with the fiber bundle. The cellulose content and the orientation degree got the higher correlation degree with single fiber tensile strength, which was 0.674 and 0.640. The highest factor associated with the fiber bundle tensile strength was the orientation degree, the correlation degree was 0.747. The hemicellulose content and the crystallinity also got high correlation degree with the fiber bundle strength, which was 0.687 and 0.640.

To comprehensively evaluate the influence of different ratios of Carex meyeriana and cotton on yarn properties and encourage the C.meyeriana to applicate textile garments,this study used the method of fuzzy and comprehensive evaluation to evaluate the yarn properties of 12/88,25/75,37/63,46/54 ratios of C.meye-riana and cotton by measuring the fracture strength,elongation at break,hairiness,the evenness,knots, slubs,neps.The results of this study showed that the membership degrees of four different blended ratios were 0.370 5,0.238 6,0.210 4,and 0.180 5,respectively.indicating that lower C.meyeriana content was beneficial to the yarn’s comprehensive performances,in which the yarn properties of C.meyeriana/cotton 12/88 was the best in the four different blended ratios.The yarn properties of 25/75,37/63 blended ratios were similar.Dif-ferent C.meyeriana/cotton blended ratio could be chosen with the different demands.These results provide the basis for C.meyeriana fibers’application in textile garments.

In this paper, the pyrolysis behaviors and the release of volatile organic compounds (VOCs) of the curaua fiber and hemp fiber were investigated. Fourier transform infrared spectrometer (FTIR) was employed to analyze the main chemical composition of the curaua fiber and hemp fiber. The chemical composition mass fraction was tested by chemical method. The pyrolysis behaviors and the release of VOCs of the curaua fiber and hemp fiber could be investigated by thermogravimetry-mass spectroscopy (TG-MS). The activation energy of each stage during the fiber pyrolysis was calculated by the Coats-Redfern method. The results revealed that the main chemical components of the curaua fiber were the same to the hemp fiber, which were cellulose, hemicelluloses, lignin, pectin, wax and hydrotrope. The cellulose mass fraction of the curaua fiber (56.35%) was lower than that of the hemp fiber (71.37%), but the lignin mass fraction of the curaua fiber (19.70%) was higher than that of the hemp fiber (2.86%). The pyrolysis process of the curaua fiber and hemp fiber could be divided into 3 stages. In the first stage (50-250℃), the residual water and free water in the amorphous region evaporated. The next 2 stages were mainly the hemicelluloses pyrolysis (250-350℃) and the pyrolysis process of cellulose and lignin (350-700℃), respectively. The 3 independent first-order reaction models were constructed to describe the main pyrolysis process of the curaua fiber and hemp fiber. The first first-order reaction of the curaua fiber was mainly the hemicelluloses pyrolysis stage (265-356℃), the second first-order reaction of the curaua fiber was mainly the cellulose pyrolysis stage (356-426℃), and the third first-order reaction was mainly the lignin pyrolysis stage (426-463℃). The activation energies of the second and third first-order reaction stages (205.41, 497.56 kJ/mol) were higher than that of the first first-order reaction stage (125.06 kJ/mol). The activation energy in each stage was closely linked to the chemical composition and the mass fraction of each composition. Through the combination of the thermal analysis instrument and the mass spectrometer, it was detected that small amounts of formaldehyde, acrolein, and other VOC gas such as n-butane, benzene substance were released during the curaua fiber pyrolysis. The investigated result can be useful to the application of the curaua fiber, which can be developed as a kind of functional fiber, but the retardant problem and the environmental issues should be given attention to during the curaua fiber application.

为了探究四种洋麻/芳纶不同混纺比对其混纺织物增强复合材料力学性能的影响,对以环氧树脂为基体,精细化处理的洋麻和对位芳纶不同混纺比机织物为增强体的复合材料进行力学性能测试,并对洋麻纤维扫描电子显微镜(SEM)及傅里叶红外光谱(FTIR)测试分析纤维表面粗糙度及极性变化,从而来分析力学测试结果.结果表明,洋麻/芳纶30/70混纺织物增强复合材料弯曲强度最高,为248.81MPa,弯曲模量为12.91GPa,与纯芳纶织物增强复合材料相比,分别提高4.9％和7.1％;而洋麻/芳纶20/80混纺织物增强复合材料剪切强度最高,为24.58MPa,与纯芳纶织物增强复合材料相比,提高18.6％.SEM及FTIR表明洋麻纤维精细化处理后,纤维表面粗糙度增加,极性降低,提高了增强体与树脂的界面结合力,从而改善了复合材料的弯曲、剪切性能.

In order to extract more excellent properties of Carex meyeriana fibers applied in textile processing,this study adopted the laccase to treat C. meyeriana fibers. We used laccase dosage,p H,temperature as exploring factors,and the lignin content,fiber diameter,fracture strength as the evaluation index for response surface method to optimize the laccase treatment process. The results revealed that the optimize levels were 14% dosage of laccase,5. 5 of the p H and47 ℃ of the temperature,and the lignin content,diameter and fraction strength was 7. 71%,40. 06 μm and 203. 46 MPa,which decreased 60. 86% and 53. 04% and increased 34. 94% comparing to before treatment,respectively. We also tested the C. meyeriana fibers acquired by the optimized process through super depth of field,scanning electron microscope,FTIR and XRD. The super depth of field showed that the C. meyeriana fibers became finer,more uniform and softer; The Scanning electron microscope test and FTIR test showed that the pectin on the C. meyeriana fibers had further removed; The XRD test showed that the crystallinty increased from 57. 09% to 64. 53%. The above results indicate that the laccase treatment could improve the performance of the C. meyeriana fibers and be benefit for the application in textile processing.

为研究麻纤维化学成分对其增强复合材料界面性能的影响,选取麻纤维纤维素、半纤维素、果胶、木质素、水溶物、脂蜡质成分含量及回潮率作为影响因素,以麻纤维/不饱和聚酯树脂(UP)复合材料界面性能作为影响结果,构建Back Propagation (BP)神经网络的训练样本.首先,利用灰关联分析法对影响麻纤维/UP复合材料界面性能的因素进行关联度计算;其次,按照影响程度的大小进行排序,建立3层BP神经网络模型进行迭代训练;最后,预测麻纤维化学成分含量对麻纤维/UP复合材料界面性能的影响.预测结果表明:学习结束后模型的输出比较接近实测值,说明BP神经网络具有很强的学习能力,同时也证明了将BP神经网络用于麻纤维/UP复合材料界面剪切力预测的可行性;灰关联与BP神经网络联用后预测精度得到大大提高,预测误差最大可减小83.28％.

In order to prepare a new kind of natural fibers and analysis its properties, the curaua fiber was extracted by the method of ultrasound-alkali-H2O2 one-bath technology. The four parameters of ultrasonic time, alkali treatment time, the concentrations of NaOH and H2O2 were optimized by multiple indicator orthogonal experimental method based on the evaluation factors of fibers diameter, breaking strength and moisture regain. The basic physical properties, adiathermic property together with the antibacterial property of curaua fibers were evaluated. Further more, the mechanism of adiathermic property and the antibacterial composition were explored. The results show that the optimal parameters were ultrasonic time of 70 min, alkali-oxygen one bath time of 100 min, alkali weight concentration of 8 g/L, hydrogen peroxide weight concentration of 12 g/L in the solution of 0.75 L. The extracted curaua fibers are 47.19 μm in diameter, 152.59 mm in length, 2.03×10 4 MPa in tensile strength and 15.33% in moisture regain, which are comparable with ramie fibers. The curaua/cotton(70/30) net with the CLO value of 1.316 and the thermal resistance of 0.204 m2 K/W, has certain warmth retention property, which is slightly lower than wool fibers net. In vitro antibacterial test,we found that curaua fiber has excellent antibacterial effect to colibacillus and staphylocccus aureus. In addition, the SEM pictures show that there are lumens in the cross section of the fibers. The filter liquor of curaua fiber has flavonoids of antimicrobial substances, which was tested by the ultraviolet spectroscopy.