w(残余单体)对聚丙烯腈聚合物及原丝性能影响

在相同聚合条件下完成聚合,聚合完成后进行脱单,根据实验需要调整脱单工艺,设计了w(残余单体)=10%、7%、4%、2%、1%、0.5%6种条件实验,在纺丝机头收取不同条件下聚丙烯腈合液样品,对聚合液样品的转化率、落球黏度、增比黏度进行测试;在相同纺丝条件下收取不同条件的聚丙烯腈聚原丝样品,对样品进行力学性能分析和截面形状分析。结果表明,随着w(残余单体)的下降,机头纺丝液转化率、落球黏度下降,增比黏度上升;随着w(残余单体)的降低,原丝单丝强度、拉伸模量上升,断裂伸长下降;在相同纺丝条件下,尤其是相同凝固条件下,随着w(残余单体)的下降,原丝截面从圆形向"腰形"转变。     

最新专利

<正>干喷湿纺低膨润度聚丙烯腈初生纤维的方法公开号CN 109137117A/公开日2019-01-04/申请人中复神鹰碳纤维有限责任公司题述方法先将衣康酸胺与丙烯腈、引发剂过硫酸铵进行聚合反应,制备的聚合原液经过脱单脱泡处理后,再进行原液的氨化处理,获得pH值为7～10的高固含量、高亲水性纺丝原液,然后纺丝原液经过干喷湿纺纺丝,在凝固浴中通过滴加氨水的方式控     

聚丙烯腈原丝毛丝形成与控制工艺研究

从纺丝生产工艺方面对聚丙烯腈(PAN)原丝毛丝形成的因素和控制进行了试验。研究表明:纺丝液应反应程度均一,有适宜的PAN相对分子质量和较窄的分布,并须经严格的脱单、脱泡及分级过滤;较缓的凝固过程和合理匹配凝固浴浓度、温度、循环量并辅以氨化处理等工艺优化;合理的水洗工艺可有效降低二甲基亚砜(DMSO)的残余质量分数;优质的油剂和合理的上油工艺;合理的干燥致密化工艺;分段牵伸,总牵伸倍数的控制等工艺优化,可有效避免和控制原丝制备过程中毛丝的形成。     

最新专利

<正>一种硫酸处理辐照改性聚丙烯腈预氧化纤维的制备方法公开号CN 106192362A/公开日2016-12-07/申请人仇颖超题述制备方法为以聚丙烯腈(PAN)为原料,预处理后与有机溶剂混合得均一透明纺丝液,将其进行真空干燥、脱泡、纺丝、固化、冻干得PAN原丝,然后对原丝改性处理得改性PAN原丝,最后将改性原丝拉伸、预氧化、硫酸处理、洗涤、干燥得硫酸处理辐照改性PAN预     

碳纤维用聚丙烯腈聚合试验装置简介

简要介绍了碳纤维用聚丙烯腈聚合设备的工艺流程,如原料输送、蒸馏、聚合、脱单、过滤、脱泡,并对配套设备及原丝制作注意事项进行了介绍。     

专利文摘

<正>碳纳米管改性的聚丙烯腈基碳纤维原丝及其制备方法本发明涉及一种碳纳米管改性的聚丙烯腈基碳纤维原丝及其制备方法,组分包括:碳纳米管和聚丙烯腈,其质量分数比为1%～20%:80%～99%;制备包括,⑴?将聚丙烯腈溶解在溶剂中,配成质量分数为3%～45%的聚丙烯腈溶液,过滤,脱泡;⑵?将聚丙烯腈的溶剂与水配成纺丝凝     

超重力脱单釜在聚丙烯腈聚合物脱单中的应用

为了降低高性能碳纤维用聚丙烯腈聚合液中w(残余单体),通过使用超重力脱单釜进行脱单。考察了超重力脱单釜的转速、温度、真空度、填料组合形式对脱单效果的影响。实验结果得出转子最佳转速为400r/min、温度为60℃、真空度为-0.095MPa的条件下,填料内斜型-栅格型-外斜型-栅格组合形式脱单效果最好,w(残余单体)可降至0.1%。同时也考察了两种不同形式脱单釜对高性能碳纤维原丝及对应碳丝性能的影响。结果得出原伞盘式脱单釜制备碳丝强度为5.01GPa,超重力脱单釜制备碳丝强度为5.51GPa。最后,通过工艺调优得出,最佳工艺条件下的超重力脱单釜明显优于原伞盘式脱单釜。     

腈纶二步湿法原液过滤探讨

二元共聚硫氰酸钠二步湿法纺丝过程中需要将聚丙烯腈溶液经过滤、脱泡送纺丝工序进行纺丝;过滤能去除3 0μ以下的粒子,减少对纤维成形的影响.就过滤效果问题进行探讨.     

专利文摘

聚丙烯腈碳纤维原丝的制备方法聚丙烯腈碳纤维原丝的制备方法,将丙烯腈与少量的丙烯酸甲酯、衣康酸溶解在49%～54%硫氰酸钠溶液中进行均相聚合,形成的聚合体留在硫氰酸钠溶液中,成为均相高分子溶液原液,经多级精密过滤、脱泡、调温后纺丝;纺丝以组合喷丝板喷丝,顺流长浸浴凝固成型,经水洗、两段水浴牵伸、上油、热辊烘干后,即制得性能优异的聚丙烯腈碳纤维原丝,生产流程短,工艺简单,采用先水洗后牵伸的工艺,通过调整牵伸倍数和牵伸浴长度制得断裂伸长均匀的原丝,使产品的断裂伸长不匀率控制在10%以内,聚丙烯腈碳纤维原丝是制备阻燃性能优异…     

壳聚糖纺丝原液制备及湿法纺丝工艺初探

研究了壳聚糖纺丝原液在真空脱泡和静置脱泡条件下的表观牯度和特性粘数的变化规律,讨论了尿素、醋酸钠等添加剂对纺丝原液性能的影响,在模拟纺丝设备上进行了纺丝,对纤维力学性能进行了初步分析.结果表明:真空脱泡条件下,壳聚糖纺丝原液粘度随脱泡时间的增加呈先下降后上升的趋势;在静置脱泡条件下,原液粘度呈下降趋势,随着时间的增加,其粘度下降趋缓;在壳聚糖纺丝原液中加入醋酸钠可提高原液的粘度,加速冻胶的形成;加入尿素,纺丝原液粘度下降,纺丝原液中的醋酸钠与壳聚糖摩尔比为0.2～0.4时,纤维力学性能较好.     

On the origin of order-disorder in drawn polyacrylonitrile

Drawn polyacrylonitrile can be characterized only insufficiently with regard to its molecular and supermolecular structures which substantially determine the physical properties. This paper points out that the so-called “superstructure” of polyacrylonitrile fibers can be cleared up after suitable thermooxidative treatment using x-ray small-angle scattering technique. The chemical reactions during the thermo-oxidative treatment lead to a “self-contrasting” effect so that the fibers as such are severely damaged yet information about the supermolecular structure can be obtained. The investigations show that changes in the course of fiber production (spinning, drawing, and annealing processes) affect alterations of the superstructure. The described method of investigation represents a so far unknown possibility for the purpose of detecting the supermolecular structure of drawn polyacrylonitrile.     

Effect of comonomers on melt processability of polyacrylonitrile

This work is concerned with the feasibility of achieving melt‐processable polyacrylonitrile copolymer systems as precursors for the manufacture of carbon fibers. Identification of suitable comonomers and achieving the optimum content of the comonomer were some of the main objectives of this investigation. It was seen that methyl acrylate (MA) was found to be suitable for enabling the melt processing of polyacrylonitrile (PAN), in terms of melt viscosity, time stability, and char yield. Below 10 mol % of MA, the PAN copolymer exhibited no flowability, even at very low molecular weights (～ 20,000). The long‐range order inherently present in PAN is speculated to be broken down at a critical value of about 10% MA at 220°C in the PAN‐based system, enabling its melt flowability. It was also seen that the incorporation of MA was seen to improve the temperature and molecular weight window of processability of the PAN system. The molecular weight cutoff for the 90/10 mol % acrylonitrile/methyl acrylate (AN/MA) system was about 50,000 at 220°C, whereas it was increased to about 100,000 in the presence of 15 mol % MA comonomer. Feasibility studies on the use of other comonomers such as higher acrylates and acrylamides were also conducted. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 69–83, 2002     

Bicontinuous porous membranes with micro-nano composite structure using a facile atomization-assisted nonsolvent induced phase separation method

The micro-nano composite structure can endow separation membranes with special surface properties, but it often has the problems of inefficient preparation process and poor structural stability. In this work, a novel atomization-assisted nonsolvent induced phase separation method, which is also highly efficient and very simple, has been developed. By using this method, a bicontinuous porous microfiltration membrane with robust micro-nano composite structure was obtained via commercially available polymers of polyacrylonitrile and polyvinylpyrrolidone. The formation mechanism of the micro-nano composite structure was proposed. The microphase separation of polyacrylonitrile and polyvinylpyrrolidone components during the atomization pretreatment process and the hydrogen bonding between polyacrylonitrile and polyvinylpyrrolidone molecules should have resulted in the nano-protrusions on the membrane skeleton. The membrane exhibits superhydrophilicity in air and superoleophobicity underwater. The membrane can separate both surfactant-free and surfactant-stabilized oil-in-water emulsions with high separation efficiency and permeation flux. With excellent antifouling property and robust microstructure, the membrane can easily be recycled for long-term separation. Furthermore, the scale-up verification from laboratory preparation to continuous production has been achieved. The simple, efficient, cost-effective preparation method and excellent membrane properties indicate the great potential of the developed membranes in practical applications.     

聚丙烯腈纤维水泥基复合材料抗干缩开裂性能研究

本文研究了在较低体积掺量下(≤1％)，聚丙烯腈纤维对水泥基材料的抗干缩开裂性能的影响，同时分析了其作用机理。结果表明，在合理掺量下聚丙烯腈纤维可以有效的延缓水泥基材料裂缝的扩展并减小裂缝的张开度。     

黄豆蛋白改性腈纶的研制

采用丙烯腈对黄豆蛋白进行疏水改性后,将其与聚丙烯腈共混纺丝,用常规腈纶的生产工艺纺制吸湿和吸水性良好的黄豆蛋白改性腈纶。采用黄豆蛋白质量分数为33％的改性黄豆蛋白与常规聚丙烯腈原液共混纺丝,当黄豆蛋白质量分数为10％时,获得的改性腈纶断裂强度2.75 cN／dtex,断裂伸长率25.4％,回潮率1.7％,保水率8.3％。     

Highly Aligned Centrifugal Spun Polyacrylonitrile Nanofibers Collected and Processed with Automated Tracks

A parallel automated track collector is integrated with a rationally designed centrifugal spinning head to collect aligned polyacrylonitrile (PAN) nanofibers. Centrifugal spinning is an extremely promising nanofiber fabrication technology due to high production rates. However, continuous oriented fiber collection and processing presents challenges. Engineering solutions to these two challenges are explored in this study. A 3D-printed head design, optimized through a computational fluid dynamics simulation approach, is utilized to limit unwanted air currents that disturb deposited nanofibers. An automated track collecting device has pulled deposited nanofibers away from the collecting area. This results in a continuous supply of individual aligned nanofibers as opposed to the densely packed nanofiber mesh ring that is deposited on conventional static post collectors. The automated track collector allows for simple integration of the postdraw processing step that is critical to polymer fiber manufacturing for enhancing macromolecular orientation and mechanical properties. Postdrawing has enhanced the mechanical properties of centrifugal spun PAN nanofibers, which have different crystalline properties compared with conventional PAN microfiber. These technological developments address key limitations of centrifugal spinning that can facilitate high production rate commercial fabrication of highly aligned, high-performance polymer nanofibers.     

Solubility of Highly Isotactic Polyacrylonitrile in Dimethyl Sulphoxide

The solubility of highly isotactic acrylonitrile homopolymer into dimethyl sulphoxide (DMSO) was measured. The dissolution of polymer increases drastically at temperature greater than some critical threshold and this process is a thermodynamic equilibrium process. It is shown that the dissolution temperature can be summarized as a function of molecular structural parameters. The dissolution temperature decreases with addition of KCl and NaCl and effect of NaCl is more prominent than KCl. As the concentration of KCl and NaCl increases beyond 0.025 mol/L, the dissolution temperature then increases. There is a decrease in the dissolution temperature of polyacrylonitrile containing sodium ethoxide and sodium hydroxide, and the dissolution temperature increases as the concentration of sodium ethoxide and sodium hydroxide increases beyond 0.01 mol/L. The dissolution temperature of polyacrylonitrile increases continuously with addition of diethylamine. A relationship between the dissolution temperature and the value of isotacticity of polyacrylonitrile was quantitatively obtained.     

潮汐-连续流组合人工湿地对污染河水的净化特性

构建了具有不同运行方式的两级垂直流人工湿地。连续运行1 a的结果表明:潮汐-连续流组合人工湿地能够有效地净化污染河水,其对COD、BOD5、SS、TP、TN、NH3-N的年平均去除率分别为85.6%、94.7%、98.7%、85.6%、74.1%、87.7%;采用间歇(潮汐)运行方式的一级垂直流人工湿地不仅能够实现对COD、BOD5、SS 90%左右的去除,而且还能够促进二级连续垂直流人工湿地对NH3-N、溶解态TP的有效去除;前置潮汐流湿地同二级连续流人工湿地相比,前者更利于植物的生长,在连续和间歇运行的垂直流人工湿地中植物对氮去除的贡献均高于对磷去除的贡献。     

The effect of pre-carbonization on the properties of PAN-based carbon fibers

A continuous stabilization and two-stage carbonization process was used to prepare polyacrylonitrile (PAN)-based carbon fibers, The effect of pre-carbonization (300 to 550°C) on the final properties and microstructure of carbon fibers was measured. Experimental results using an X-ray diffractometer indicated the presence of a less ordered structure at 2Θ from 5 to 18° in the pre-carbonized fibers and the final carbon fibers. This study found that the pre-carbonization process strongly affects the microstructure of the resulting carbon fibers. The results also showed that a suitable pre-carbonization was very conducive to improvement in tensile strength or in Young's modulus of the final carbon fibers. When the final carbon fiber was pre-carbonized at 300 and 550°C, respectively, these fibers had a higher tensile strength and higher Young's modulus than carbon fibers pre-carbonized at other conditions.     

The use of ultrafiltration for treatment of spent solventcleaning rinses from nickel-plating operations: membrane material selection study

Solvent-resistant hollow-fiber OF membranes were selected by measurement of fiber swelling and treatability studies on spent solvent cleaning rinse. The experimental results indicated that the membranes made of both cellulose acetate (CA) and polyacrylonitrile (PAN) materials could tolerate the solvent present and were suitable for treating the spent solvent rinses, whereas polyethersulfone and polysulfone membranes were not suitable. The CA membrane had the lowest fouling tendency when treating the spent solvent rinse. The results also showed that retentions of the emulsified solvent and oil-grease for the CA membrane were above 96% and 80%, respectively, and the PAN membrane had better retention than the CA membrane. It was hypothesized that there might be a critical micellar concentration for oil-grease for the PAN membrane.