共查询到19条相似文献,搜索用时 144 毫秒
1.
2.
选择环保型溶剂N-甲基吗啉-N-氧化物水合物(NMMO·H_2O),成功实现了醋酸纤维素(CA)的溶解并制备了均匀透明的醋酸纤维素/N-甲基吗啉-N-氧化物水合物(CA/NMMO·H_2O)溶液,流变测试表明,CA/NMMO·H2O溶液均匀稳定。经过干喷湿纺工艺制备的醋酸纤维素纤维,断裂强度达到3.0c N/dtex,高于以丙酮为溶剂通过干法纺丝得到的醋酸纤维素长丝的强度。分析其原因,干喷湿纺纺丝过程中的喷头拉伸比大,所制备的醋酸纤维素纤维有较高的链段取向度和晶区取向度。所制备的醋酸纤维素纤维的沸水收缩率、接触角和回潮率与商业化的干法纺丝制备的醋酸纤维素长丝相当。 相似文献
3.
4.
《现代化工》2016,(3)
以芒草为原料,用Na OH/H_2O_2溶液体系预处理制备芒草纤维,在冰醋酸环境下,以浓硫酸为催化剂与醋酸酐酯化制备芒草醋酸纤维素。优化了预处理条件:温度、时间、次数和酯化条件:催化剂量、温度、时间、醋酸酐量,最佳条件下制备出的芒草纤维的纤维素、半纤维素和木质素的质量分数分别为75.3%、17.3%、5.1%,制备出芒草醋酸纤维素的取代度DS=2.8,特性黏度[η]=1.24 d L/g,达到美国联邦贸易委员会指南认定的三醋酸纤维素标准。利用扫描电镜(SEM)和热分析(TG、DSC)对制得样品进行表征。结果表明,可以利用Na OH/H_2O_2水溶液体系预处理芒草原料制备芒草纤维,并进一步酯化制备出高取代度的醋酸纤维素。 相似文献
5.
6.
以体积比为1∶2的N,N-二甲基甲酰胺和丙酮为溶剂、钛酸四丁酯[Ti(OiPr)4]和氯化钒[VC13]为前驱体、醋酸纤维素(CA)为模板,采用静电纺丝法制备了V-TiO2/醋酸纤维素纳米纤维.将V-TiO2/醋酸纤维素纳米纤维用0.1 mol/L NaOH/乙醇溶液水解得到V-TiO2/纤维素纳米纤维.在500℃煅烧V-TiO2/纤维素纳米纤维5h,得到直径为(200±53)nm的V-TiO2纳米纤维.利用扫描电子显微镜、X射线粉末衍射仪和紫外-可见漫反射光谱对纤维形貌、物相和结构进行了表征.以染料罗丹明B为目标降解物考察了纤维的光催化活性.结果表明:掺杂少量V后,TiO2对紫外光的最大吸收峰和吸收带边发生了红移,说明V-TiO2对光响应更宽、光利用率更高.TiO2和V-TiO2纳米纤维在20min内对罗丹明B的降解率分别为67%和77%. 相似文献
7.
《塑料工业》2018,(11)
以5,5-二甲基海因和1-溴-3-氯丙烷为原料合成了一种水溶性卤胺抗菌前驱体3-(3'-氯丙基)-5,5-二甲基海因(CPDMH),利用核磁共振氢谱确定了产物结构。CPDMH与醋酸纤维素(CA)溶液共混后静电纺丝,经次氯酸纳溶液处理后得到卤胺抗菌纳米纤维膜。研究了CA质量分数、电压、接收距离对纳米纤维形貌的影响;探讨了纳米纤维膜的抗菌性能和活性氯水释放性能。结果表明,纺丝溶液质量分数为10%、电压为20 k V、接收距离为15cm,得到的纳米纤维平均直径为342 nm。氯化后的纳米纤维膜可在1 min内杀灭金黄色葡萄球菌和大肠杆菌,活性氯在水中释放稳定,对环境无害。 相似文献
8.
9.
10.
研究了中低温稀酸预处理对皇竹草化学组成变化、纤维素酶水解得率与总糖得率的影响,并采用扫描电镜(SEM)对皇竹草纤维结构变化进行了分析.结果表明,随着硫酸浓度的增大、温度的升高和时间的延长,半纤维素含量大幅度降低,且预处理后纤维素酶水解得率也逐渐增大.较好的预处理条件为100 g皇竹草原料,在固液比1:5(g:mL)条件下,用质量分数4.0%硫酸在温度110 ℃下,经过8 h预处理后,纤维素保留率为87.48%,半纤维素水解率为93.68%,所得固体渣经纤维素酶水解72 h后得率为86.3%(纤维素酶用量40 FPIU/g,以纤维素质量计),100 g原料可得到总糖量为54.53 g.预处理后皇竹草纤维表面和细胞壁受到破坏,表面积增大,有利于纤维素酶水解作用的进行. 相似文献
11.
Cellulose triacetate (CTA) fibers were spun from a 35% (w/v) solution of CTA (molecular weight, 95,000) in trifluoroacetic acid (TFA)/CH2CL2 (60/40, v/v) using laboratory-scale spinning equipment, an air gap, and cold MeOH as the coagulant. The resulting fibers, of large diameter (ca. 80 μm) were saponified with a variety of reagents. The regenerated cellulose fibers had tenacities and moduli as high as 1.6 and 50 GPa, respectively. The fiber properties did not show a dependence on which cellulose polymorph was present. It is suggestes that for highly oriented fibers, the cellulose molecular weight is the primary parameter that determines the strength and modulus. This emphasizes the advantages of using a lyotropic cellulosic mesophase which permits relatively low solution viscosities at high concentrations and high polymer molecular weights. © 1995 John Wiley & Sons, Inc. 相似文献
12.
Samuel P. Kusumocahyo Toshiyuki Kanamori Takashi Iwatsubo Kimio Sumaru Toshio Shinbo Hideto Matsuyama Masaaki Teramoto 《应用聚合物科学杂志》2006,102(5):4372-4377
A new preparation method for polymer inclusion membrane (PIM) was developed. The preparation method—called post‐treatment method—is very convenient to prepare a hollow fiber PIM. Using this method, a commercial cellulose triacetate (CTA) hollow fiber membrane can be easily converted into a hollow fiber PIM. Thus, a CTA hollow fiber membrane was allowed to swell in 2‐nitrophenyl‐n‐octyl ether (NPOE) in the presence of chloroform as a solvent for CTA and N,N,N′,N′‐tetraoctyl‐3‐oxapentane diamide (TODGA) as a carrier. After evaporating chloroform, a hollow fiber PIM containing NPOE and TODGA was obtained. The result of the transport experiment of cerium(III) ions using the hollow fiber PIM showed that cerium ions were effectively transported from the feed solution to the strip solution through the hollow fiber PIM, indicating that the hollow fiber PIM was successfully prepared using the post‐treatment method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4372–4377, 2006 相似文献
13.
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。 相似文献
14.
15.
Binary blends of poly(caprolactone) (PCL) with cellulosic esters [cellulose diacetate (CDA), cellulose acetate–butyrate (CAB), and cellulose triacetate (CTA)] were studied by using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and wide-angle X-ray scattering (WAXS) techniques, and qualitative comparison was made with the results obtained by polarizing optical microscopy. The PCL–CAB system was proved to be partially miscible, whereas PCL–CDA and PCL–CTA appeared to be immiscible. A double-melting behavior was showed for PCL–CAB and PCL–CTA blends. As these peaks did not shift by varying the heating rate of DSC runs, this behavior can be due to melting of two populations of crystals of PCL, which may be different in size. On the other hand, blends of PCL containing a low amount of CAB or CDA seem to develop more crystallinity for the PCL than this polymer alone. The solvent seems to have a certain influence on the thermal and morphological behaviors of the as-cast blends of these three systems, affecting the extent of crystallinity of PCL, as well as its Tm and ΔHf. This finding is discussed in the light of WAXS and polarizing optical microscopy results. © 1994 John Wiley & Sons, Inc. 相似文献
16.
采用湿法纺丝,以乙醇、氯化钙和盐酸的混合溶液为凝固浴制备了改性酪蛋白(CLC)/羧甲基纤维素钠(CMC-Na)共混纤维。通过测试纺丝液流动性以及纤维的红外光谱、表面形态和力学性能,研究了CLC和CMC-Na不同配比与纺丝溶液pH改性后酪蛋白纤维的力学性能增加,纺丝溶液的流动性与CMC-Na维的红外光谱分析表明CLC与CMC-Na之间有良好的相互作用。CMC-Na质量分数为30%(相对于改性酪蛋白)的共混纤维性能较好,纤维表面较致密,有沿着纤维轴向取向的明显条纹,其断裂强度为341.19MPa。 相似文献
17.
18.
玉米黄浆是玉米淀粉生产中产生的主要下脚料,其中大约含有60%的蛋白质。为了合。理利用这些蛋白质,对玉米黄浆的脱色工艺进行了研究,并初步探讨了其在蛋白质复合纤维上的应用。首先,筛选出脱色效果较好的H2O2做为氧化性脱色剂;其次,探讨H2O2脱色工艺中反应浓度、时间、温度及pH值对脱色效果的影响,并由正交试验得出脱色处理最佳工艺为:H2O2浓度为70g/L,pH值为8,反应温度为70℃,反应时间为60min。由红外谱图可以看出脱色前后浆液中蛋白质基本无明显变化.脱色后浆液纺制的蛋白质复合纤维白度明显提高,断裂强度和断裂伸长率均略低于原浆液纺制的纤维。 相似文献