高强高模聚乙烯纤维电子预辐照接枝反应的研究

为了改善高强高模聚乙烯纤维(PE)与环氧树脂的粘接性,通过电子预辐照接枝工艺对PE纤维表面进行改性。试验发现,在N_2气氛下电子预辐照接枝反应工艺并不需要引发剂,随着预辐照剂量、反应温度和反应时间的增加,反应接枝率增加;丙烯酸是较好的接枝单体,丙酮与苯是较好的反应溶剂,反应结束后PE纤维表面上的均聚物可以用苯来去除;当预辐照剂量低于1.56×10~4Gy时,对纤维拉伸强度影响不大,而SEM和ATR—IR分析证实了PE纤维表面上有极性基团的存在。     

UHMWPE纤维表面紫外辐射接枝改性的研究

有氧开放体系下,采用紫外辐射接枝方法对超高分子量聚乙烯纤维织物表面进行改性．探讨了单体种类、浓度,引发剂,抗氧剂,接枝方法等不同因素对UHMWPE纤维织物表面处理效果的影响。通过SEM、红外光谱仪法分析了表面处理的超高分子量聚乙烯纤维织物外观形貌,并测试了以其作为增强材料的复合材料的层间剪切强度。研究结果表明,在有氧开放体系下,经紫外辐射接枝方法改性的超高分子量聚乙烯纤维织物,其粘结性得到了改善,由其制备的复合材料界面结合力得到加强,其层间剪切强度高于未经紫外处理制备的复合材料。     

电子束预辐照接枝反应研究（I）──聚乙烯醇纤维接枝丙烯酸

研究了电子束预辐照聚乙烯醇纤维接枝丙烯酸的接枝规律。发现．随着预辐照剂量的增大、反应时间的延长或反应温度的提高，聚乙烯醇纤维的接枝率首先增大，然后增大趋缓并趋向定值，而随着丙烯酸浓度的增大，纤维接枝率具有一个峰值，少量摩尔盐加入到聚合体系中，可以有效地抑制乙烯醇纤维的接枝反应。     

预辐射接枝法制备离子交换纤维的研究

以^60Coγ射线为辐射源，对聚丙烯纤维在空气中进行预辐照，然后将样品置于丙烯酸水溶液体系中进行接枝反应。研究了辐射剂量对接枝率的影响，纤维的力学性能、吸水率以及接枝率与离子交换能力的关系。结果表明：随着辐射剂量的增加，接枝率明显提高，接枝率可达到1600％以上。接枝后的纤维仍有较好的力学性能和很高的吸水性能，离子交换容量随接枝率的提高而不断增长。     

N2等离子体接枝处理丙纶改性及染色的初步研究

丙纶纤维具有显著的物理化学优点，但丙纶纤维染色困难制约了其应用与发展。本研究用氮气等离子体对丙纶纤维进行表面处理，然后用丙烯酸接枝丙纶纤维。用傅立叶变换红外光谱和扫描电镜分析改性前后样品。结果表明：等离子体表面处理接枝后的丙纶纤维能染上鲜艳的阳离子艳兰。     

弱酸型阳离子交换纤维PVF-g-AA的制备

用γ-射线预辐射接枝共聚的方法制备了一种弱酸型阳离子交换纤维PVF-g-AA，分析了温度、时间、单体浓度、交联剂以及预辐照剂量和辐照后PVF的保存时间对接枝共聚反应的影响。研究表明：当反应温度为50—60℃、单体浓度15％一20％、共聚时间60min时，接枝率最高。     

电子束预辐照接枝反应研究（Ⅱ）──维尼纶纤维接枝丙烯酸

研究了电子束预辐照维尼纶纤维接枝丙烯酸，考察了预辐照剂量、反应时间、单体的质量分数、反应温度和摩尔盐对接枝反应的影响，以及接技后纤维力学性能的变化，并对电子束预辐照接枝反应机理进行了初步探讨。     

丝素蛋白纤维的接枝聚合（Ⅱ）：无引发剂存在时丝素蛋白纤…

研究了无引发剂存在时丝素蛋白纤维与烯类单体的接枝聚合反应，与四价铈盐引发的接枝聚合相比，无外加引发剂存在时的接枝聚合，可以获取高得多的接枝率和单体的接枝效率，这种接枝聚合方法是丝素蛋白纤维的一种更为有效的改性方法，接枝０．６％２－羟基－４－丙烯酰氧二苯酮（ＨＡＯＰＢ）的丝蛋白纤维，其热稳定性及紫外稳定性均得了到显著的改善，但力学性能没有下降。     

芳纶浆粕纤维的辐照改性研究

将芳纶浆粕纤维经NaOH溶液处理后再在氧气和空气两种不同的氛围中用60Co-γ进行辐照改性,研究辐照后芳纶浆粕纤维的吸收剂量和气体氛围对芳纶浆粕纤维的影响.结果表明,经NaOH溶液处理的芳纶浆粕纤维表面发生了变化,接触角降低;经γ射线辐射改性后,纤维表面粗糙度增大,产生了一定的横断纹;芳纶浆粕纤维在氧气氛围中经辐射改性,当其吸收剂量为50～300 kGy时,纤维表面的接触角增大,亲水性提高.     

UHMWPE纤维的低温等离子体/丙烯酰胺接枝改性

运用低温等离子体对超高分子量聚乙烯(UHMWPE)纤维进行处理后,浸润能力提高了3.75倍.继而在纤维表面接枝丙烯酰胺单体,得出接枝的最佳工艺是:在40℃的1.0mol/L的丙烯酰胺水溶液中加热1.5h.结果表明:处理后的纤维基本上维持高拉伸性能和整体形貌,在纤维长链表面引入了酰胺基极性基团,增大了纤维与其他基质材料之间的化学键合能力和咬合能力,提高了纤维的表面性能.     

Surface Graft Polymerization of PET and PE Fibers by UV Irradiation and Their Characteristics

Polyethylene terephthalate(PET)and polyethylene(PE)fibers were surface photo-grafted with acrylic acid(AA)by using UV irradiation photochemical initiationduring a continuous winding process within 1-2 min-utes.The grafted fibers were characterized by measure-ments of dye uptaking,moisture regain,pull-out forcesof monofilament from cured matrix,as well as by analy-sis of ESCA and ATR-FTIR spectra.All these resultsconfirm that the surface behavior of the UV-irradiationgrafted fibers was greatly improved.It was also provedthat the original excellent mechanical properties of the fi-bers were well-retained after the surface grafting treat-ment.     

VAPOR PHASE PHOTOGRAFTING OF ACRYLIC ACID ON PE FIBERS

The surface of high strength and high modulus polyethylene (PE) fiber has been modified bygrafting with acrylic acid.Benzophenone and acrylic acid in vapor phase were UV-irradiated in thepresence of the PE tiber substrate.Grafting with acrylic acid took place in a thin layer on the sur-face,thus increasing the surface adhesion of PE fiber with epoxy resin.This paper dealt withphoto-polymerization reactions including the role of photoinitiator.The degree of graft increasedwith the enhancing of reaction time,reaction temperature and concentration of initiator.Acetonewas used as carriers of monomer and tiator and able to initiate and promote grafting to the sur-face.ATR-IR and SEM measurements on the grafted surface showed that some polar groups wereintroduced to the surface of PE fibers.Oligomer which existed during the polymerization could beremoved by washing with benzene.     

Structural Changes of Polyethylene Terephthalate Fibers Grafted by Acrylamide

A group of grafted PET fibers with different graft yield are formed by grafting acrylamide onto the PET main chains. The structure of grafted fibers are studied by scanning electronic microscope ( SEM ), infra-red spectrophotometer ( IR ), and differential scanning calorimetry(DSC). At the same time, the moisture regain, dyeability, strength, and elongation at break of the samples are measured and their relations with structural changes are discussed. Compared with ungrafted fiber, shape of the fiber cross-section, IR characteristic absorption peaks, and melting behavior of the grafted fibers have been changed, causing the fiber dyeability and moisture regain to be increased, and mechanical properties to be changed.     

Structures of Silk Fibers Grafted with Hexafluorobutyl Methacrylate

The relationship between the graft yield and the effect of hexafiuorobutyl methacrylate graft treatment on the structural changes of the silk fibers was studied on the basis of the results of scanning electron micrograph photographs （SEM）, infrared spectroscopy （IR）, Raman spectrum, wide-angle X-ray diffraction patterns （WAXD）, nuclear magnetic resonance（NMR） and amion acid analysis. The results showed that the crystalline regions of grafted fibers were hardly affected and the fiber fission occurred on the cross sections of grafted fibers. The surface of fibers was covered with a high polymer film. The Raman spectrum showed there was little change in the conformation of grafted fibers which mainly remained β-sheet conformation. The IR of the grafted silk fibers showed new absorption of bands occurred which belonged to the stretching-vibrationabsorption-peak bands of Vo-o and VC-F of aliphatic ester species. The CF3-, -CF2- and -CFH- grafted silk macromodecul were verified in the NMR spectrum. The amion acid analysis indicated fluoride monomers were inclined to graft with TYR, ARG and CLU silk fibers.     

丝素蛋白纤维的接枝聚合（Ⅱ）──无引发剂存在时丝素蛋白纤维接枝烯类单体

研究了无引发剂存在时丝素蛋白纤维与烯类单体的接枝聚合反应．与四价铈盐引发的接枝聚合相比，无外加引发剂存在时的接枝聚合，可以获取高得多的接枝率和单体的接技效率．这种接枝聚合方法是丝素蛋白纤维的一种更为有效的改性方法．接枝０．６％２－羟基－４－丙烯酰氧二苯酮（ＨＡＯＢＰ）的丝素蛋白纤维，其热稳定性及紫外稳定性均得到了显著的改善，但力学性能没有下降．     

萃取干燥处理对UHMW-PE冻胶丝拉伸性能的影响

为了改善 UHMW—PE 冻胶丝的拉伸性能,本文对 UHMW—PE 冻胶丝的萃取和干燥工艺条件进行了研究.结果表明冻胶丝的最大拉伸倍数依赖于萃取和干燥条件,如:萃取剂、干燥过程中的限制收缩率、干燥温度和干燥时间.在萃取和干燥过程中的过量收缩会引起冻胶丝内部缺陷的产生,导致冻胶丝可拉伸性的恶化.本文以最优化实验,获得了以溶剂汽油为萃取剂对冻胶丝处理的最佳萃取和干燥条件是:多次萃取和5%限制收缩干燥.经最佳实验条件处理的冻胶丝在超高倍拉伸过程中是稳定的,并可制得强度为37.3cN/dtex 和模量为1731.0cN/dtex 的长丝.     

Enhancement of Adhesive Strength of Ultrahigh Molecular Weight Polyethylene Fibers Prepared by Polar Polymer Implantation

A new technique was proposed to enhance the adhesive strength of ultrahigh molecular weight polyethylene （UHMWPE） fibers. Polar polymer was implanted into UHMWE gel fibers during extracting process and can then be trapped on the surface of the fibers after subsequent ultra-drawing. The physical and chemical changes in the fiber structure were examined with scanning electron microscopy （SEM） and Fourier transform infrared （FTIR） spectroscopy. The mechanical and interfacial adhesion properties of UHMWPE fibers were investigated with tensile testing. The results showed that there were polar groups on the smface of pretreated UHMWPE fiber. The interracial shear strength of UHMWPE fibers with epoxy resin was greatly improved without sacrificing the excellent mechanical p~perties of fibers. After pretreated with ethylene/vinyl acetate copolymer （EVA）, the shear strength of the interface between fiber and epoxy resin increased from 1.06 to 2.49 MPa, while the integrated mechanical properties d the pretreated UHMWPE fibers were still optimal.     

Adhesion of PBO Fiber in Epoxy Composites

The high mechanical and thermal performance of poly p-phenylene- 2, 6-benzobisoxazole ( PBO ) fiber provides great potential applications as reinforcement fibers for composites. A composite of PBO fiber and epoxy resin has excellent electrical insulation properties, therefore, it is considered to be the best choice for the reinforcement in high magnetic field coils for pulsed magnetic fields up to 100 T.However, poor adhesion between PBO fiber and matrix is found because of the chemically inactive and/or relatively smooth surface of the reinforcement fiber preventing efficient chemical bonding in the interface, which is a challenging issue to improve mechanical properties. Here, we report the surface modification of PBO fibers by ultraviolet (UV)irradiation, O2 and NH3 plasma, as well as acidic treatments. The interfacial adhesion strength values of all the treatments show the similar level as determined for aramid fibers by pull-out tests, a significant impact on fibermatrix-adhesion was not achieved. The surface free energy and roughness are increased for both sized and extracted fibers after plasma treatments together with maleic anhydride grafting. The sized fiber shows marginal improvement in adhesion strength and no change in fiber tensile strength because of the barrier effect of the finish.For the extracted fiber, different surface treatments either show no apparent effect or cause reduction in adhesion strength. Atomic force microscopy (AFM) topography analysis of the fracture surfaces proved adhesive failure at the fiber surface. The fiber surface roughness is increased and more surface flaws are induced, which could result in coarse interface structures when the treated fiber surface has no adequate wetting and functional groups. The adhesion failure is further confirmed by similar adhesion strength and compression shear strength values when the fiber was embedded in various epoxy resins with different temperature behavior. The tensile strength of fiber is sensitive to surface treatment conditions as revealed by a bimodal Weibull statistical distribution analysis. Considerable strength reduction occurred, particularly for cases of acidic and plasma treatments, while UV irradiation shows the better ability to retain fiber strength.     

聚四氟乙烯的表面改性及粘接性能研究

采用Ar等离子体技术对聚四氟乙烯(PTFE)片材表面预处理,再用热接枝的方法引发甲基丙烯酸缩水甘油酯(GMA)对其表面进行接枝改性.考察不同等离子体处理条件及接枝单体体积分数对PTFE与钢粘接强度和与水接触角的影响.同时,对接枝后的PTFE用x射线光电子能谱(XPS)进行分析表征.研究结果表明,GMA单体成功地接枝到PTFE表面,当等离子体处理时间为5min、功率为50W、气氛压力为50Pa、单体接枝体积分数为20%时,改性后的PTFE与钢的拉剪强度由处理前的24.6N·cm-2增加到处理后的284.6N·cm-2.     

氧化石墨纳米薄片表面接枝聚乙二醇

利用甲苯二异氰酸酯(TDI)作为连接剂,将聚乙二醇接枝在氧化石墨纳米薄片(GONPs)表面。氧化石墨选用改良的Hummers方法制备,并用过量的TDI进行化学改性。经过改性后的氧化石墨在无水二甲基甲酰胺中剥离形成氧化石墨纳米薄片,随后在氮气保护下接枝上聚乙二醇。用X-射线衍射、傅里叶红外及元素分析对产物进行研究表征。