接枝改性腈纶织物亲水性能的研究

利用等离子体辐照引发聚丙烯腈纤维大分子,进行反相微乳液接枝聚合,在腈纶织物上接枝季胺盐类单体(F单体),以改善腈纶织物的亲水性能,借助红外光谱和扫描电镜对改性腈纶进行表征,探讨了改性腈纶织物的吸水性、回潮率、透气性及力学性能与其接枝率的关系。结果表明:F单体已接枝到腈纶织物上,接枝率和回潮率呈线性关系;当接枝率为20%左右时,回潮率达到约7%;当接枝率小于20%时,对腈纶织物透气性影响较小;随着接枝率的增加,腈纶织物的抗弯刚度减小,断裂强力和伸长有所增加。     

静电纺丝法制备抗静电腈纶及其性能

在聚丙烯腈(PAN)聚合原液中加入一定量的聚苯胺(PAN)I,用静电纺丝法制备抗静电腈纶。采用单纤维强力机、扫描电子显微镜和纤维比电阻试验仪对抗静电腈纶的结构和性能进行测试,研究了PANI的加入量对抗静电腈纶的断裂强力、结构和抗静电性能的影响。结果表明:随着PANI加入量的增加,纤维的断裂强力降低,当PANI的加入量过大时,纤维的断裂强力下降严重;同时,随着PANI加入量的增加,纤维的体积比电阻减小。     

聚氨酯/聚苯胺导电复合材料的制备与应用

概述了聚氨酯与新型导电聚合物聚苯胺的复合材料的制备原理、工艺及性能等,包括聚氨酯内部渗透法、聚苯胺包裹法、共聚/接枝及化学氧化/电化学聚合等,对应用不同制备方法制作的聚氨酯/聚苯胺导电复合材料的性能做了比较,并对聚氨酯/聚苯胺导电复合材料的研究前沿和应用前景做了介绍。     

聚苯胺包覆炭黑的性能研究

本实验主要通过原位聚合方法,在苯胺的盐酸环境中,以炭黑和阳离子表面活性剂、阴离子表面活性剂为原料,过硫酸铵作为氧化剂,制备了炭黑/聚苯胺导电复合粒子,并对其性能测试进行了表征。在上一步的基础上,用阴离子表面活性剂(十二烷基苯磺酸钠)制备炭黑/聚苯胺导电复合粒子作为导电填料,分别以聚乙烯和聚乙烯-丙烯酸共聚物为基体,乙烯-乙酸乙烯酯为增塑剂,制成塑料电极板,然后进行性能测试。结果表明:聚苯胺为10%和15%时,塑料电极板具有较高的抗拉强度和较好的导电性。     

溶胀处理煤对煤结构与煤基聚苯胺导电性影响

首次选用苯胺为溶剂对神府煤(SFC)进行溶胀处理,以研究其对煤结构与煤基聚苯胺导电性的影响,对其结构进行TG/DSC、FTIR和SEM分析,并通过溶胀SFC处理煤为聚合基体,在苯胺和引发剂条件下聚合为煤基聚苯胺,测定了其导电率。结果表明:苯胺溶胀处理破坏了煤中非共价键,降低了煤的交联缔合度,疏松了煤的孔结构,在此条件下的煤基聚苯胺的导电率均小于溶胀处理前原煤为聚合基体的煤基聚苯胺导电率,这与煤大分子网络结构受到一定程度破坏有关,这可为煤基聚苯胺的扩大化生产提供重要参考。     

聚苯胺尼龙导电织物的制备及其传感性能

采用低温原位聚合法在尼龙织物表面形成一层聚苯胺导电材料，并用场发射扫描电子显微镜和显微拉曼成像光谱仪对其形貌及化学组成进行表征，用万用表和电化学工作站测试其导电性能。结果表明，聚苯胺聚合在尼龙织物的表面，赋予织物较好的导电性，织物电导率为31.62 S/m。聚苯胺尼龙织物的电阻随应变的增大而增大，当应变回复到初始状态时，织物电阻逐渐恢复并接近初始值，在3500次拉伸-回复循环后仍有96.2%的高循环稳定性。作为导电织物，聚苯胺尼龙织物具有良好的传感性能，在0~15%应变范围内可以准确监测人体的关节运动。同时，聚苯胺尼龙导电织物也具有热电性能，织物的塞贝克系数为8.406μV/K，有望作为温差传感器。     

聚苯胺改性负载型纳米二氧化钛的研究

采用悬浮聚合法制备聚苯乙烯微珠载体,通过矿化接枝技术将溶胶-凝胶法制备的纳米二氧化钛负载在微珠载体上,制成负载型纳米二氧化钛光催化剂。利用导电聚苯胺对负载型纳米二氧化钛光催化剂进行可见光改性研究,通过XRD,SEM等方法对负载型纳米二氧化钛光催化剂进行表征;通过光催化降解甲基橙实验评价了导电聚苯胺改性负载型纳米二氧化钛光催化剂在可见光条件下的光催化活性。实验结果表明：导电聚苯胺对负载型纳米二氧化钛光催化剂的改性,可有效改善负载型纳米二氧化钛光催化剂在可见光条件下的光催化性能,降解率提高了24.5%。     

聚苯胺包覆玻璃鳞片复合物的制备与表征

采用化学聚合和乳液聚合两种方法制备聚苯胺包覆玻璃鳞片复合物。通过XRD、红外光谱、SEM、表面接触角测试、电导率测试、EIS等手段对复合材料的结构、形貌和性能进行了表征。结果表明:不同方法制备的聚苯胺包覆玻璃鳞片复合材料在结构、微观形貌和电导率上有较大差别,其中乳液法制备的复合材料,聚苯胺在玻璃鳞片载体上能够生长成较长的纤维,具有较高的结晶度,电导率高达2.281 S/cm。最后以之为导电填料,制备环氧防腐导电涂料,经研究表明其具有优异的导静电、防腐性能和机械性能。     

表面活性剂对炭黑/聚苯胺电导率的影响

本课题主要研究了阳离子表面活性剂用量、阴离子表面活性剂以及复配的阴阳离子表面活性剂用量三方面对炭黑/聚苯胺复合粒子的电导率的影响,通过扫描电镜、四探针电导率测试仪对其进行了测试和表征。利用原位聚合法,合成了导电性能更为优良的添加表面活性剂的炭黑/聚苯胺复合粒子;在苯胺/阳离子表面活性剂摩尔质量比在5:1时,炭黑/聚苯胺复合粒子的电导率达到最高,数值为4 142.052 S·cm-1,比未加表面活性剂的要高出3个数量级;添加阴离子表面活性剂的炭黑/聚苯胺复合粒子的电导率也得到了提高,且比添加同比例的阳离子表面活性剂的相对高些;而添加复配的阴阳离子表面活性剂对炭黑/聚苯胺复合粒子的电导率的影响不大,但比未加表面活性剂的要高出2个数量级。本实验采用在苯胺和炭黑的聚合体系中添加表面活性剂,获得了导电率较高的炭黑/聚苯胺复合粒子,比未加表面活性剂的炭黑/聚苯胺复合粒子要高出3个数量级,且在扫描电镜的照片上观察到的效果较好。     

聚苯胺/涤纶导电织物再掺杂及洗涤性能的研究

采用现场吸附聚合法制备了聚苯胺 /涤纶导电织物 ,采用不同种类的酸对其进行再掺杂 ,研究了酸的种类对织物导电性能的影响 ,并对导电织物进行了洗涤实验及洗涤牢度实验。结果表明 :无机酸对导电织物的掺杂效果优于大多数有机酸。导电涤纶织物的导电性能受洗涤液酸碱度的影响 ,其中碱性洗涤液使导电性能降低 2个数量级 ,酸性洗涤液使导电性能下降 1个数量级 ,而且聚苯胺在涤纶织物表面具有良好的附着性     

Grafting of poly(acrylic acid) onto cellulosic microfibers and continuous cellulose filaments and characterization

Results from the grafting of poly(acrylic acid) (PAA) onto cellulosic microfibers and continuous cellulose filaments are presented. The grafting of PAA onto cellulosic fibers offers the possibility of developing enhanced ion exchange and fluid absorbency on the fibers. The grafting of PAA was carried out with a two‐step procedure. First, vinyl‐terminated ethoxy silane was deposited on the surface of the fiber. This was followed by a grafting polymerization reaction in aqueous media of acrylic acid with different concentrations of potassium persulfate (KPS), which acted as the initiator. The percentage of grafting increased with increasing KPS concentration and reached a maximum value at a concentration of about 0.4 wt % with respect to the weight of the fiber. The grafted copolymer was characterized by Fourier transform infrared spectroscopy. Strong evidence that the grafting reaction was successful was given by the presence of a band, with a maximum at 1732 cm^?1, that was characteristic of carbonyl group absorption and was not initially present in the cellulosic fibers. The water absorption of the cellulosic microfibers grafted with PAA was three times greater than the water absorption of the nongrafted microfibers. The mechanical properties of continuous cellulose filaments did not change drastically with PAA grafting. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 386–393, 2002     

The Distribution of Irradiation-Grafted Acrylic Acid in the Cross-Section of Polypropylene Fibers

Abstract

The relative efficiency of grafting of acrylic acid (AA) in the surface layer and in the bulk of preirradiated polypropylene fibers was studied by combining the ATR and transmission IR techniques. At graft percentage from 41 to 98, the surface layer contains 2–3 times higher concentration of the grafted chemical groups than the fiber bulk. At 140% of AA, the surface of the host polymer becomes screened by the grafted material.     

Thermal stability of grafted fibers

This paper presents the experimental results on the study of thermal stability of grafted fibers, i.e., polypropylene-, polyester-, and rayon-grafted fibers. These fibers were obtained by radiation grafting processes using hydrophylic monomers such as 1-vinyl 2-pyrrolidone, acrylic acid, N-methylol acrylamide, and acrylonitrile. The thermal stability of the fibers was studied using a Shimadzu Thermal Analyzer DT-30. It was found that the thermal stability of the fibers, which can be indicated by the value of the activation energy for thermal degradation, was not much improved by radiation grafting. The degree of improvement depends on the thermal stability of the monomers used for grafting. The thermal stability of a polypropylene fiber, either a grafted or an ungrafted one, was found to be inferior compared to the polyester of a rayon fiber, which may be due to the lack of C?O and C?C bonds in the polypropylene molecules. The thermal stability of a fiber grafted with acrylonitrile monomer was found to be better than that of an ungrafted one. However, no improvement was detected in the fibers grafted with 1-vinyl 2-pyrrolidone monomer, which may be due to the lower thermal stability of poly(1-vinyl–2-pyrrolidone), compared to the polypropylene or polyester fibers.     

Grafting modification of electrospun polystyrene fibrous membranes via an entrapped initiator in an acrylic acid aqueous solution

Ultrafine electrospun polymer fibers, with their large specific surface areas, have not found wide applications partly because the fiber surfaces usually carry an insufficient quantity of active groups. The electrospinning and surface‐grafting copolymerization of polystyrene fibrous membranes were carried out via the embedded radical initiator approach. The results from X‐ray photoelectron spectroscopy show that the initiator added to the polystyrene dope was deliberately expelled onto the fiber surfaces. The microstructure and hydrophilicity of the grafted membranes were investigated with Fourier transform infrared spectroscopy, scanning electron microscopy, and water contact angle and water uptake capacity measurements. An increase in the initiator dosages led to decreases in the grafting rate, water uptake, and hydrophilicity of the grafted membranes; the opposite was true for increases in the neutralization of acrylic acid (AA). However, the grafting, water uptake, and hydrophilicity of the grafted membranes presented nonlinear relationships with the concentration of AA. The initiator emigration technique will provide a facile and feasible platform for the surface‐grafting modification of electrospun membranes. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Grafted carbon fibers and their physicochemical properties. I. Grafting of methacrylic acid onto carbon fibers

A simple, reproducible method for grafting different carbon fibers (modified and unmodified, high‐modulus, and high‐tensile) with methacrylic acid is presented. The grafted carbon fibers were characterized by wetting measurements and electrokinetic studies. Scanning electron microscopy micrographs showed grafted polymer chains on all carbon fiber surfaces. The success of the grafting procedure depends on a suitable modification of the fiber surface. The amount and size of the grafted polymer chains on modified carbon fibers depend on the amount of initiator used. Contact angle measurements indicate an increase of the contact angle versus water and a decrease versus diiodomethane. The surface polarity calculated from the surface tensions obtained from contact angle values decreases for all systems under investigation. Zeta (ζ) potential measurements confirmed these results. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1175–1185, 1999     

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。     

Scanning electron microscopy study of chemically modified coir fibers

Chemical‐surface modification of coir fibers was done by dewaxing, using an alkali treatment (5% and 10% NaOH), vinyl grafting with methyl methacrylate (MMA) and cyanoethylation. The chemically modified fibers were characterized by Fourier transform infrared (FTIR) spectroscopy. In addition, the surface features of untreated, dewaxed, alkali‐treated, grafted, and cyanoethylated coir fibers were studied using scanning electron microscopy (SEM). Progressive changes in surface morphology were observed. SEM observations showed the removal of tyloses from the surface of coir as a result of alkali treatment (5%), resulting in a rough fiber surface with regularly spaced pits. At a lower percentage of grafting (PMMA), the surfaces became more or less uniform, while the surfaces of the coir fibers with a higher percentage of grafting were increasingly covered with grafted materials, resulting in canal‐like cavities between the overgrowths of the grafted materials on the unit cells. Cyanoethylated coir‐fiber surfaces showed an insufficient deposit of cyanoethyl groups. SEM analysis of the samples was corroborated by measurements of a mechanical property (maximum stress at break). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1169–1177, 2001     

Chemically induced graft copolymerization of vinyl monomers onto cotton fibers

We investigated the chemically induced graft copolymerizations of acrylic acid (AA), acrylamide, crotonic acid, and itaconic acid (IA) onto cotton fibers. Benzoyl peroxide was used as an initiator. The effects of grafting temperature, grafting time, and monomer and initiator concentrations on the grafting yields were studied, and optimum grafting conditions were determined for the sample material. The maximum grafting yield value obtained was 23.8% for AA. Swelling tests, Fourier transform infrared spectroscopy, and scanning electron microscopy analyses of grafted and ungrafted fibers were also performed to characterize fiber properties. IA‐grafted fibers were measured as the most swollen fibers, with a swelling value of 510%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2343–2347, 2006     

Lipases improve the grafting of poly(ethylene terephthalate) fabrics with acrylic acid

In this study, poly(ethylene terephthalate) (PET) fabrics were modified with two types of commercial lipases, namely, Lipex and Lipolase, and grafted with acrylic acid (AA) to improve their absorption properties. The effects of the enzyme concentration, reaction temperature, time, and pH on the grafting of AA onto PET were investigated. The pretreatment of PET with lipases increased the amount of AA that was introduced to the PET fibers, whereas AA grafting onto the untreated PET fabrics led to lower graft yields. Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the AA‐grafted pretreated polyester fabrics. A new band appearing at 1546 cm^?1 in the Fourier transform infrared spectrum implied that AA was introduced onto the PET fabrics. The surfaces of the fabric fibers presented in scanning electron microscopy micrographs clearly indicated the formation of a layer of grafted poly (acrylic acid). The results show that the density of surface grafting was improved by the lipase pretreatment. The increase in grafting was higher for Lipex than for Lipolase. The highest graft yield was obtained with 1% Lipex and Lipolase for 30 min at pH values of 7 and 5, respectively. There were no significant changes in the tenacity or weight reduction of the fabrics. The moisture content of the samples increased linearly with increasing graft yield. This was higher for the pretreated fabrics grafted with Lipex. A higher color strength was obtained for grafted PET samples that were pretreated with Lipex when they were dyed in alkaline aqueous solutions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Radiation-grafting of acrylic acid onto ultrahigh molecular,high-strength polyethylene fibers

Radiation-induced grafting of acrylic acid onto ultrahigh molecular weight (UHMW) high-strength polyethylene fibers to impart heat resistance and dyeability was undertaken. A preirradiation method was employed for grafting in an aqueous solution of acrylic acid containing a small amount of Mohr's salt as inhibitor. The grafting rate for UHMW high-strength polyethylene fibers is one-tenth of that for high-density polyethylene fibers currently in use, and one-hundredth, for high-density polyethylene film. It has become clear that the preirradiation dose should be as low as 1 Mrad to keep the high strength of the starting fibers. The starting UHMW high-strength polyethylene fiber begins to shrink remarkably at around 145°C, showing a maximum shrinkage of 90%, and then breaks at 154°C. When a 24% acrylic acid graft is converted to calcium salt, the grafted fiber retains the fiber form even at 300°C and gives only a maximum shrinkage of 11%. The less than 1% acrylic acid graft UHMW high-strength polyethylene fibers and their calcium salt can be dyed to a deep shade with cationic dyes, whereas the starting fibers cannot be dyed with usual dyes including the cationic dye. © 1993 John Wiley & Sons, Inc.