水解条件对改性腈纶染色性能的影响

探讨了水解温度、氢氧化钠浓度和水解时间对改性腈纶的染色性能的影响。纤维水解后结构发生了变化,用阳离子染料上染水解纤维时,染料的平衡上染量有较大的提高。提高水解温度、增加氢氧化钠浓度和延长水解时间,均能提高改性腈纶的染色性能。考虑到纤维的力学性能,较为适宜的水解条件为氢氧化钠质量分数12％～15％,水解温度低于90℃,水解时间为12～15 min。     

高吸水腈纶纤维的研制

用碱减量法对腈纶纤维进行表面改性，控制碱浓度为8％，水解时间为10分钟，水解温度为90℃，可以得到吸水率达54％的高吸水腈纶纤维。     

腈纶接枝蛋白质水解条件对吸水率和接枝率的影响

研究了腈纶表面接枝蛋白质水解工艺条件对吸水率和接枝率的影响关系。通过红外光谱分析结果证实了腈纶纤维已接枝上大豆蛋白。实验结果还表明,水解时间、水解温度及NaOH浓度都对腈纶纤维的吸水率和接枝率有很大的影响。在一定的水解强度范围内,腈纶的吸水率及接枝率均随水解强度的增加而不断提高;当水解强度过高时,接枝率反而会下降。腈纶表面接枝蛋白质的最佳水解工艺条件为:水解时间15 min、水解温度为90℃、NaOH浓度为10%。X-射线衍射分析表明,腈纶经过水解、接枝后,纤维的聚集态结构没有明显变化。     

蛋白质接枝改性腈纶的水解工艺研究

采用NaOH溶液对腈纶进行水解,表面接枝蛋白质制得改性腈纶。讨论了NaOH浓度、水解温度、水解时间对腈纶接枝效果的影响。结果表明:在水解反应温度80~90℃、NaOH溶液质量分数14%、水解时间15 m in时,改性腈纶接枝率较高。力学性能分析和电镜表面观察表明:在腈纶表面接枝大豆蛋白质,不仅可以赋予纤维表面完整的蛋白质覆盖层,而且还可以较好的弥补纤维因水解而产生的表面损伤和力学性能下降等缺陷。     

利用腈纶废料制备高吸水性树脂

本文介绍了腈纶废料制备高吸水性树脂的过程,阐述了利用腈纶废料制备高吸水性树脂的原理。将废旧腈纶在碱性条件下水解、中和、洗涤后,分别阐释了水质对吸水树脂吸水率的影响,温度、时间对腈纶水解反应的影响,以及交联剂用量和种类对产物吸水率的影响。     

丙烯腈系纤维

<正>20141126氢氧化钠水解聚丙烯腈的表征Hu X.…;Advanced Materials Research,2011,p.333(英)聚丙烯腈纤维在其聚合物链中包含至少质量分数为85%的丙烯腈共聚体。聚丙烯腈纤维中的氰基(-CN)在NaOH水溶液中水解后转换为羧基(-COOH)。研究用铬黄法表征氢氧化钠溶液中共聚丙烯腈纤维的水解。其最佳的水解技术是:氢氧化钠的质量分数为12%,时间为10 min,温度为80℃。另外,还用扫描电子显微镜对聚丙烯腈纤维和改性聚丙烯腈纤维     

聚丙烯腈酸性水解至羧酸研究

本文以腈纶为原料,在酸性条件下水解成含聚丙烯酸的PAN纤维。探讨和研究酸的性质、浓度、时间、温度对水解产率的影响,得出一些工艺参数,为聚丙烯腈的综合应用提供基础数据。     

聚天冬氨酸合成中的水解反应实验研究

通过聚天冬氨酸合成中水解反应的一系列实验,讨论了氢氧化钠用量和浓度、水解温度、搅拌时间、搅拌转速等对产物聚天冬氨酸阻垢性能的影响。结果表明:水解的适宜条件为NaOH与聚琥珀酰亚胺质量比为0.46∶1左右,NaOH浓度40%,水解温度25℃,搅拌时间10～15min,搅拌中转速,在此工艺条件下,产物聚天冬氨酸的阻垢性能优异。     

凝胶态腈纶的染色工艺与结构性能研究

主要研究了阳离子染料浓度、染色时间、染色温度等工艺条件对凝胶态腈纶上染率的影响,得出染料质量分数高于6%、染色时间大于20 s时,上染率基本达到饱和。研究还发现染色温度的最佳范围为45～50℃。在优化染色条件后测试了染色后纤维的色牢度、纤维结构,发现纤维的沾色牢度达到4～5级,纤维的断裂伸长率有所降低,但对纤维的微晶态结构没有较大影响。研究结果对凝胶染色腈纶的工业化生产有非常好的指导作用。     

黄麻纤维增强不饱和聚酯树脂初步研究

以油酸为偶联剂,将氢氧化钠-油酸处理后的黄麻纤维布作为填充材料制备了不饱和聚酯复合材料,并对氢氧化钠处理黄麻纤维的适宜浓度、复合材料的拉伸强度、冲击强度、吸水率进行了研究测试。结果表明:氢氧化钠的适宜浓度为20%,黄麻纤维增强不饱和聚酯树脂的冲击强度及拉伸强度最大值分别为12.75 kJ/m2和33.05 MPa,复合材料的最大吸水率为4.07%。经油酸处理的黄麻纤维可有效提高不饱和聚酯复合材料的性能。     

NaOH/尿素冷冻活化木材纤维的工艺研究

利用NaOH/尿素混合水溶液在冷冻条件下对木材纤维进行活化处理,通过无胶胶合压制纤维板的力学性能测试、傅里叶变换红外光谱以及X射线衍射分析表征了木材纤维的冷冻活化效果。结果表明：冷冻条件下NaOH/尿素的混合水溶液对木材纤维具有一定的活化效果,优选的活化工艺为NaOH和尿素的总质量（NaOH与尿素质量比为7：12）与木材纤维质量比为1：12,冷冻温度-15℃,冷冻时间1.0 h,木材纤维含水率20%。木材纤维经NaOH/尿素混合水溶液冷冻活化后,所得无胶胶合板材的静曲强度和内结合强度分别由未处理的32.16和0.29 MPa提高至45.53和1.21 MPa,吸水率和厚度膨胀率由未处理的53.95%和22.57%降低至43.62%和10.34%。傅里叶变换红外光谱和X射线衍射表征发现,NaOH/尿素混合水溶液的冷冻活化破坏了木材纤维中纤维素的氢键结构,促使了纤维素I型晶格扩张,产生了新的结晶变体,使分子缔合程度变小,木材纤维表面的羟基活性增强。     

胶束催化肉桂油水解制备苯甲醛

用微量量热法研究了十二烷基硫酸钠(SDS)和十六烷基三甲基溴化铵(CTAB)胶束对天然肉桂油碱性水解的催化作用,并考察了反应温度、时间、pH对该水解反应的影响。实验室实验及工厂放大实验结果表明,当反应温度为368-375 K、选择碳酸钠和三乙醇胺为混合碱调节pH=10、m(肉桂醛)∶m(水)=1∶4、c(CTAB)=2.03×10-3mol/L、反应时间14 h时,苯甲醛得率最高达61%。     

木质纤维的冷冻活化及其制备无胶板材

利用氢氧化钠-聚乙二醇-尿素混合溶液对木质纤维进行冷冻活化处理,然后制备无胶纤维板,通过对比无胶胶合纤维板力学性能,确定木质纤维较佳冷冻活化工艺,并利用傅里叶变换红外光谱、X射线衍射分析、差式扫描量热分析、热重分析、X射线光电子能谱分析对木质纤维的冷冻活化效果进行表征。研究结果表明:木质纤维较佳冷冻活化工艺为氢氧化钠、聚乙二醇、尿素的质量比7∶4.2∶12,活化剂质量(以氢氧化钠与尿素的总质量计)与木质纤维的质量比1∶12,冷冻温度-15℃,冷冻时间45 min;以此工艺活化处理的木质纤维为原料,所制备纤维板的吸水厚度膨胀率、内结合强度、静曲强度、弹性模量分别优于GB/T 11718—2009《中密度纤维板》性能要求(各指标数值分别提升了45%、238%、177%和129%);冷冻活化处理会破坏木质纤维中纤维素间的氢键,提高羟基的反应活性并增加活性羟基的数量,在扩张纤维素晶格的同时产生新的结晶并且降低木质纤维的热稳定性。     

Prediction of water retention capacity of hydrolysed electrospun polyacrylonitrile fibers using statistical model and artificial neural network

Box Behnken design of experiment was used to study the effect of process variables such as alkali concentration, temperature and time on water retention capacity of the alkaline hydrolysed electrospun fibres. The hydrolysis of electrospun polyacrylonitrile fibres was carried out using sodium hydroxide with different processing conditions like concentration of alkali, temperature and time. With the increase in the concentration of alkali, time and temperature, the water retention capacity of membrane was found to increase in the membranes. Water retention capacities of the membranes were modeled and predicted using empirical as well as artificial neural network (ANN model). The fiber diameter and mean flow pore diameter of electrospun polyacrylonitrile fibers and hydrolyzed fibers shown in SEM images were 310 ± 50, 275 ± 75 nm, 0.9258 and 1.12 microns, respectively. The present study indicated that the nanofibrous membranes have potential for the water absorbing applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

均匀试验设计法提取米糠中阿魏酸工艺优化

使用碱醇提取法从米糠中提取阿魏酸,采用HPLC法检测阿魏酸的含量。设计均匀试验,考察了阿魏酸的提取率与氢氧化钠浓度、提取温度、提取时间、氢氧化钠与乙醇比、固液比的关系,实验表明,阿魏酸最佳提取条件为:用1.3%的氢氧化钠溶液与乙醇按5.6∶1的比例混和,83.2℃下提取2.8 h,固液比为1∶9.4,提取液中加入0.2 g/L的亚硫酸钠溶液作为抗氧化剂,最大提取率为514 mg/100g。     

Hydrolysis of poly(acrylamide)–starch graft copolymer

Poly(acrylamide)–starch graft copolymer was treated independently with sodium hydroxide and different acid solutions. The different acids include phosphoric, hydrochloric, and sulphuric acid. The treatment was carried out under a variety of conditions including sodium hydroxide concentration, time, and duration of hydrolysis as well as type of acid used. The extent of hydrolysis was assessed by estimating amide and carboxyl content as well as the acrylate and starch content before and after treatment. It was found that the increment in carboxyl content is equal to the decrement in amide on using sodium hydroxide concentration up to 1N, while using higher concentration than 1N leads to a difference in formed carboxyl and decreased amide groups. The magnitude of this difference depends on sodium hydroxide concentration as well as temperature and duration of hydrolysis. The maximum value of carboxyl content obtained was 593 meq/100 g sample. The acidic treatment of the starch copolymer does not affect the conversion of amide groups to carboxyl groups, and the sole effect was hydrolysis of starch component of the copolymer. Evaluation of the alkali-treated copolymer as cation exchanger was carried out. The absorption efficiency % of different cations depends on the associated anions and follow the order: Cu²⁺ > Zn²⁺ > Co²⁺ > Mg²⁺. © 1995 John Wiley & Sons, Inc.     

Surface modification of polyacrylonitrile (PAN) fibers by grafting of natural polymer-soybean protein (SP)

Summary A novel method of modifying polyacrylonitrile (PAN) fibers by grafting of soybean protein (SP) onto it was studied. The reactant of PAN-g-SP fiber was prepared based on chlorination of the hydrolyzed PAN fiber. The effects of chlorination and grafting conditions on the grafting efficiency were investigated. The grafting efficiency first increases with the increase of the addition of thionyl chloride (SOCl₂), chlorination time and temperature and then levels off. In grafting reaction, grafting efficiency increases at first and then declines significantly with increasing addition of sodium hydroxide (NaOH), grafting temperature and time. The grafted polymer was characterized by FT-IR spectroscopy, X-ray diffraction and SEM images. The results indicated that SP was grafted onto the PAN fiber. PAN-g-SP also exhibits good hygroscopicty and proper mechanical properties.