含中草药成分的纤维制备与性能研究Ⅰ.柿叶/纤维素共混纤维的制备及力学性能

以二甲基亚砜(DMSO)／多聚甲醛(PF)为溶剂,添加柿叶活性成分,应用湿法纺丝技术,制得含柿叶提取物的再生纤维素纤维。研究了纺丝原液浓度、凝固浴温度、柿叶添加量对共混纤维的力学性能的影响。结果表明,当纺丝原液质量分数在10％-12％,凝固浴温度在40-50℃,柿叶提取物质量分数在5％左右,纤维具有较好的可纺性,柿叶的添加使共混纤维的结晶度、取向度、强度均有一定程度的下降。DSC测试表明柿叶与纤维素之间有较好的相容性。     

凝固浴温度对Ionicell纤维结构及性能的影响

以离子液体1-丁基-3-甲基咪唑氯盐([BMIM]Cl)为溶剂,水为凝固浴,α-纤维素质量分数95.5%的棉浆为原料,通过干湿法纺丝制备再生纤维素(Ionicell)纤维。探讨了凝固浴温度对纤维结晶结构以及力学性能的影响。结果表明:在其他相同条件下,随着凝固浴温度的升高,纤维的结晶度、双折射和非晶区取向都呈现先增大后减小的趋势,纤维的断裂强度、初始摸量也呈先增大后减小的趋势,当凝固浴温度为20℃时纤维的力学性能最佳,断裂强度为2.98 cN/dtex,断裂伸长率为3.5%,初始模量为59.7 cN/dtex。     

凝固浴浓度对离子液体法纤维素纤维结构以及性能的影响

探讨了以离子液体1-丁基-3-甲基咪唑氯盐([BMIM]Cl)为溶剂制备的纤维素纤维纺丝工艺条件中凝固浴浓度对纤维结晶结构以及力学性能的影响。实验表明:在相同拉伸比和气隙条件下,凝固浴浓度对再生纤维素纤维的结构以及性能影响较大。随着凝固浴浓度的增加,纤维的结晶度和无定形取向都呈现先增大后减小的趋势,纤维的横向晶粒变小,拉伸强度、初始模量也呈先增大后减小的趋势。     

凝固浴温度对Lyocell纤维结构及性能的影响(英文)

探讨了以 Ｎ－甲基吗啉－Ｎ－氧化物（ＮＭＭＯ）为溶剂的Ｌｙｏｃｅｌｌ纤维纺丝工艺中凝固浴温度对最大纺丝速度和纤维结构及性能的影响。实验表明：随着凝固浴温度提高,最大纺丝速度和纤维延伸度提高,而非晶态取向度、结晶度、相对强度和初始模量下降。     

离子液体/二甲基亚砜复合溶剂干喷湿纺制备再生纤维素纤维凝固工艺研究

以棉浆粕为原料,使用离子液体/二甲基亚砜复合溶剂配制纺丝溶液,采用干喷湿法纺丝工艺制备纤维素纤维。探索了气隙长度、喷头牵伸比、凝固浴浓度、凝固浴温度对纤维结构与性能的影响。结果表明当采用气隙长度2.5 cm、喷头牵伸比1.9、凝固浴浓度30%、凝固浴温度35℃时可获得力学性能最佳、取向度最高、结晶较为完善的纤维素纤维。     

凝固条件对PAN初生纤维微结构的影响

通过湿法纺丝工艺制备聚丙烯腈(PAN)初生纤维,借助于X射线衍射仪、声速仪、扫描电子显微镜、小角X光散射仪等,研究了凝固浴温度、凝固浴浓度、喷丝头拉伸等凝固条件对初生纤维晶态结构、取向结构、形态结构的影响。结果表明:PAN纤维的凝聚态结构和形态结构在初生纤维形成时已基本形成;PAN初生纤维的结晶度达40%以上,其结晶度和结晶尺寸受凝固浴温度和浓度的影响;PAN初生纤维和原丝的晶区取向和全取向随着喷丝头拉伸的增大而增大;PAN初生纤维具有沿纤维轴向高度取向的沟槽,通过改变成形条件,可以获得沟槽浅且规整性完美的纤维表面;提高凝固浴浓度,可以形成结构均质、致密的PAN初生纤维,避免皮芯结构及芯部出现较多孔洞。     

纺丝工艺对离子液体法新型纤维素纤维性能的影响

以离子液体1-丁基-3-甲基咪唑氯盐（[BMIM]C1）为溶剂,用干湿法纺丝制备了再生纤维素纤维,通过正交试验设计和系统试验,考察了气隙长度、喷头拉伸比、凝固浴浓度和凝固浴温度等工艺参数对制得的再生纤维素纤维的力学性能的影响,找出离子液体法新型纤维素纤维的最佳纺丝工艺。试验结果表明,对于该体系,纺丝工艺参数中凝固浴温度和拉伸比对纤维的拉伸强度、初始模量的影响最大,气隙长度对纤维断裂伸长影响最大。     

凝固浴温度对超高相对分子质量聚酰胺6冻胶纺纤维结构和性能的影响

以氯化钙为络合剂,采用冻胶纺丝技术制备超高相对分子质量(UHMW)聚酰胺(PA)6纤维,重点研究凝固浴温度对UHMW PA6冻胶纺纤维结构和性能的影响,以期获得高强高模PA6纤维。试验结果表明:在较低凝固浴温度(4~8℃)下得到的纤维表面较为光滑;凝固浴温度越低,分子间排列越规整,取向度越好,成品丝条的双折射率越高,越易形成α晶型,结晶度越高,所得纤维的强度和模量也较大。综合考虑力学性能测试结果和室温的影响,凝固浴温度选为8℃。     

凝固浴组分对纤维素纤维结构和力学性能的影响

采用新型碱复合溶剂NaOH／j琉脲／尿素水溶液对纤维素进行溶解,并采用H2S04／Na2SO4溶液作为凝固浴,对纤维素溶液进行湿法纺丝,获得纤维素纤维。通过改变凝固浴组分,研究纤维素纤维结构和性能的变化,获得更好的纺丝条件。研究表明,当H2S04质量分数为8％～10％,Na2SO4质量分数6％～12％时,纺丝过程稳定,纤维素纤维的力学性能较好且相对稳定。纤维素纤维的断裂强度最大值可达2．06cN／dtex,纤维素纤维横截面均呈近圆形结构,且无明显的皮芯结构,同时纤维素纤维具有纤维素II的结晶特征,凝固浴组分变化对纤维素纤维的结晶度和取向因子影响不大。     

凝固浴温度对超高相对分子质量聚酰胺6冻胶纺纤维结构和性能的影响

以氯化钙为络合剂,采用冻胶纺丝技术制备超高相对分子质量（UHMW）聚酰胺（PA）6纤维,重点研究凝固浴温度对UHMW PA6冻胶纺纤维结构和性能的影响,以期获得高强高模PA6纤维。试验结果表明：在较低凝固浴温度（4～8 ℃）下得到的纤维表面较为光滑;凝固浴温度越低,分子间排列越规整,取向度越好,成品丝条的双折射率越高,越易形成α晶型,结晶度越高,所得纤维的强度和模量也较大。综合考虑力学性能测试结果和室温的影响,凝固浴温度选为8 ℃。     

抗菌再生纤维素纤维的制备与表征

利用实验室合成的非水溶性抗菌剂——聚六亚甲基胍十二烷基苯磺酸盐(PHGDBS),与纤维素共同溶解于离子液体中,经干喷湿纺制备了抗菌再生纤维素纤维,并研究了PHGDBS对纤维结构性能的影响。结果表明:所合成的PHGDBS能够溶解于离子液体中,且对细菌和真菌均有很好的抗菌效果。PHGDBS质量分数为2%时制备的再生纤维素纤维,对金黄色葡萄球菌和大肠埃希菌的抗菌率分别达99.7%和94.5%;经水洗15次后,抗菌率仍保持在90%以上。另外,PHGDBS的加入对纤维的表面和截面形态无显著影响,虽然再生纤维素纤维的结晶度和取向度减小,纤维的断裂强度有所下降,但仍可以满足服用性能。     

X-ray studies of regenerated cellulose fibers wet spun from cotton linter pulp in NaOH/thiourea aqueous solutions

Regenerated cellulose fibers were fabricated by dissolution of cotton linter pulp in NaOH (9.5 wt%) and thiourea (4.5 wt%) aqueous solution followed by wet-spinning and multi-roller drawing. The multi-roller drawing process involved three stages: coagulation (I), coagulation (II) and post-treatment (III). The crystalline structure and morphology of regenerated cellulose fiber was investigated by synchrotron wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) techniques. Results indicated that only the cellulose II crystal structure was found in regenerated cellulose fibers, proving that the cellulose crystals were completely transformed from cellulose I to II structure during spinning from NaOH/thiourea aqueous solution. The crystallinity, orientation and crystal size at each stage were determined from the WAXD analysis. Drawing of cellulose fibers in the coagulation (II) bath (H₂SO₄/H₂O) was found to generate higher orientation and crystallinity than drawing in the post-treatment (III). Although the post-treatment process also increased crystal orientation, it led to a decrease in crystallinity with notable reduction in the anisotropic fraction. Compared with commercial rayon fibers fabricated by the viscose process, the regenerated cellulose fibers exhibited higher crystallinity but lower crystal orientation. SAXS results revealed a clear scattering maximum along the meridian direction in all regenerated cellulose fibers, indicating the formation of lamellar structure during spinning.     

New class of cellulose fiber spun from the novel solution of cellulose by wet spinning method

A novel cellulose solution, prepared by dissolving an alkali-soluble cellulose, which was obtained by the steam explosion treatment on almost pure natural cellulose (soft wood pulp), into the aqueous sodium hydroxide solution with specific concentration (9.1 wt %) was employed for the first time to prepare a new class of multifilament-type cellulose fiber. For this purpose a wet spinning system with acid coagulation bath was applied. The mechanical properties and structural characteristics of the resulting cellulose fibers were compared with those of regenerated cellulose fibers such as viscose rayon and cuprammonium rayon commercially available. X-ray analysis shows that the new cellulose fiber is crystallographically cellulose II, and its crystallinity is higher but its crystalline orientation is slightly lower than those of other commercial regenerated fibers. The degree of breakdown of intramolecular hydrogen bond at C₃[X_am(C₃)] of the cellulose fiber, as determined by solid-state cross-polarization magic-angle sample spinning (CP/MAS) ¹³C NMR, is much lower than other, and the NMR spectra of its dry and wet state were significantly different from each other, indicating that cellulose molecules in the new cellulose fiber are quite mobile when wet. This phenomenon has not been reported for so-called regenerated cellulose fibers.     

离子液体法新型再生纤维素纤维的研究

采用离子液体1-乙基-3-甲基咪唑醋酸盐([EMIM]Ac)为溶剂,制备了纤维素/[EMIM]Ac溶液,研究了该体系的流变性能,利用干喷湿纺的方式制备的新型再生纤维素纤维,并对纤维的结构与性能进行了分析。结果表明,纤维素/[EMIM]Ac溶液为典型的切力变稀流体,在较高剪切速率下,纺丝溶液的黏度变化较小;由该体系制备的新型再生纤维素纤维具有纤维素Ⅱ晶型的结构;随着拉伸比的提高,纤维的取向程度及结晶度增大,纤维力学性能提高。以离子液体为溶剂制备的再生纤维素纤维表面光滑,质地紧密。     

离子液体法制备再生细菌纤维素纤维

以离子液体(氯化1-甲基-3-正丁基咪唑)溶解高聚合度细菌纤维素(BC),采用湿法纺丝制备再生细菌纤维素(RBC)初生纤维;通过红外光谱分析(FTIR)、广角X射线衍射(WAXD)分析、热失重(TG)分析、扫描电镜( SEM)、单丝强度拉伸等表征了RBC初生纤维的结构和性能.结果表明:该溶剂体系通过10 h的快速搅拌溶...     

Regenerated cellulose membrane prepared with ionic liquid 1‐butyl‐3‐methylimidazolium chloride as solvent using wheat straw

BACKGROUND: Currently, cellulose membranes are prepared by cellulose acetate hydrolysis or chemical derivatization dissolution and regeneration using cotton pulp or wood pulp. In this study, the concept ‘lignocelluloses biorefinery’ was used, and good quality long fiber was fractionated from wheat straw using clean technologies. The objective of this study is to develop wheat straw cellulose to prepare regenerated cellulose membrane with ionic liquid 1‐butyl‐3‐methylimidazolium chloride ([BMIM]Cl) as solvent. RESULTS: Wheat straw cellulose (WSC) fractionated from wheat straw contained 93.6% α‐cellulose and the degree of polymerization (DP) was 580. WSC was dissolved directly without derivatization in [BMIM]Cl. With increase in dissolving temperature, the DP of the regenerated cellulose dropped, which resulted in a decrease in the intensity of regenerated cellulose membrane. After regeneration in [BMIM]Cl, the WSC transformed from cellulose I to cellulose II, and the crystallinity of the regenerated cellulose was lower than the original cellulose. The regenerated WSC membrane had good mechanical performance and permeability, the tensile strength and breaking elongation were 170 MPa and 6.4%, respectively, the pure water flux was 238.9 L m^?2 h^?1 at 0.3 MPa pressure, and the rejection of BSA was stabilized at about 97%. CONCLUSION: Wheat straw cellulose fractionated from wheat straw satisfied the requirement to prepare regenerated cellulose membrane using ionic liquid [BMIM]Cl as solvent. Copyright © 2012 Society of Chemical Industry     

纤维素与聚丙烯腈共混纤维的结构与性能

纤维素与聚丙烯腈溶液共混后纺丝成纤得到改性纤维。含纤维素组分多的共混纤维具有腈纶手感,良好的机械性能。用X射线衍射研究共混纤维发现,纤维素与聚丙烯腈的晶体结构同存,各纤维的结晶程度及取向度相差较小。共混纤维的扫描电镜结果表明,含纤维素多的共混纤维中,纤维素为连续相,聚丙烯腈为分散相;纤维素微纤分布于整个纤维中。含聚丙烯腈多的共混纤维中,聚丙烯腈为连续相,纤维素为分散相,两组分之间结构分离。     

基于离子液体再生的纤维素热解特性

利用离子液体1-丁基-3-甲基咪唑氯([Bmim]Cl)溶解PH-101微晶纤维素,通过不同的再生方法获得两种再生的纤维素,并利用XRD确定其结晶度,场发射扫描电镜(SEM)获得其形貌特征,热重(TG)分析表征其热稳定性.采用Py-GC/MS 对不同结晶度纤维素进行快速热解,并对热解挥发分进行在线分析,观察结晶度对纤维素热解特性的影响.研究表明左旋葡聚糖产率随结晶度降低而减少,而小分子产物随结晶度降低而增多.