紫外接枝改性PP中空多孔膜表面亲水性研究

采用紫外辐照接枝方法,以二苯甲酮(BP)为光敏剂,丙烯酸为单体,对聚丙烯(PP)中空多孔膜表面进行接枝聚合改性。研究了辐照时间、光敏剂浓度、单体体积分数和接枝时间对膜表面接枝率的影响,并以红外、扫描电镜、水通量等表征测试方法,观察了改性前后多孔膜的表面结构及亲水性效果。结果表明,在紫外光照射时间25 min,光敏剂浓度4×10~(-3)mol/L,丙烯酸体积分数35%,反应时间6 h的反应条件下,PP膜水通量最佳,亲水性得到明显改善。     

紫外辐照接枝甲基丙烯酸对无纺布性能影响的研究

以二苯甲酮作为光引发剂,利用紫外辐照法引发单体接枝聚合反应,将亲水性单体甲基丙烯酸接枝在无纺布表面对其进行改性。通过测定接枝率,评价聚合物在无纺布表面的接枝程度;通过测定未改性及改性无纺布的膜通量,考察了改性无纺布表面的透水性;通过ATR-FTIR红外光谱和扫描电镜(SEM)对改性前后无纺布进行结构表征。实验结果表明:单体体积分数20%,辐照距离20cm,辐照时间40min,光引发剂二苯甲酮浓度0.1mol/L时,接枝率和膜通量达到最大值,分别为20%和1387L/m2·h。ATR-FTIR红外光谱分析表明无纺布表面负载了亲水性-COOH。     

PBT熔喷非织造布的接枝改性研究

研究了以高锰酸钾/硫酸(KMnO4/H2SO4)为引发剂,丙烯酰胺与PBT熔喷非织造布的接枝共聚反应。考察了溶胀剂甲苯浓度、高锰酸钾浓度、硫酸浓度、预引发温度、预引发时间、丙烯酰胺浓度、反应温度及时间等因素对接枝共聚反应的影响规律。结果表明:当溶胀剂甲苯浓度为2%、高锰酸钾浓度为1.5×10-3mol/L、硫酸浓度为0.3mol/L、预引发温度为60℃、预引发时间为60min、丙烯酰胺浓度为0.35mol/L、反应温度为60℃、反应时间为3.5h时,接枝效果最佳。     

PBT熔喷非织造布的接枝改性研究

研究了以高锰酸钾/硫酸为引发剂,丙烯酰胺与PBT熔喷非织造布的接枝共聚反应。考察了溶胀剂甲苯浓度、高锰酸钾浓度等因素对接枝共聚反应的影响规律。结果表明:当甲苯质量分数为2.0%、高锰酸钾浓度为0.001 5 moL/L、硫酸浓度为0.30 moL/L、预引发温度为60℃、预引发时间为60 min、丙烯酰胺浓度为0.35 moL/L、反应温度为60℃、反应时间为3.5 h时,接枝效果最佳。     

高密度聚乙烯表面光接枝丙烯酸行为研究

研究了以二苯甲酮为光敏剂时,紫外光辐照时间、温度、丙烯酸(AA)单体浓度、预覆液中光敏剂浓度等因素对高密度聚乙烯(HDPE)接枝率和接枝效率的影响,以及接枝HDPE膜的接触角与接枝率的关系。随辐照时间延长,HDPE的接枝率增加,4min时的接枝率为15％,膜表面对水的接触角由来接枝时的83°降到36°;随接枝时间的进一步延长,接枝率不断增加,但接触角变化不大。升高温度、增加单体浓度,可以促进接枝反应的进行,使接枝率增加。预覆液中光敏剂浓度也影响HDPE的接枝率和接枝效率。红外光谱(IR)结果表明,HDPE膜表面已接枝了PAA。差热分析(DSC)结果表明,接枝破坏了HDPE的结构规整性,影响其结晶度。     

丙烯酸接枝聚酰胺/聚醚酰亚胺复合纳滤膜的制备

为了提高复合纳滤膜的抗污染性能,采用紫外光照接枝法将丙烯酸接枝到聚酰胺/聚醚酰亚胺(PA/PEI)复合纳滤膜的皮层上,通过引入羧基基团来增加膜表面的亲水性。考察了丙烯酸单体质量分数、辐照时间对表面接枝率和膜分离性能的影响,并对优选的膜进行了抗污染性能测试。结果表明:丙烯酸质量分数与紫外辐照时间对膜分离性能的影响规律相同,膜通量随质量分数的增加与辐照时间的延长呈现先增加后减小的趋势,而截留率则保持基本不变,当丙烯酸质量分数2%,辐照时间2 min时,膜的通量达到13.12 L/(m2·h),较接枝前的11.94 L/(m2·h)略高;在含有1 g/L牛血清蛋白(BSA)的溶液中,接枝后的膜通量下降明显低于接枝前的膜。研究表明丙烯酸接枝可以有效改善膜表面亲水性,从而有利于提高膜的抗污染性能。     

PP-g-(AA-AM)的制备与结构性能表征

利用电子束预辐照粉末聚丙烯,水溶液中引发丙烯酸(AA)和丙烯酰胺(AM)接枝共聚合,制备了PP-g-(AA-AM)接枝共聚物。研究预辐照剂量、反应时间、单体比例与浓度对接枝率的影响,用FTIR和接触角测量仪分析其结构和表面性能。结果表明:辐照剂量为5kGy,反应时间为3h,AM/AA单体比例为(60/40～0/100),AM单体浓度为(3～5mol·L-1),AA(2～3mol·L-1)时,接枝率较高;FTIR结果证明,AA和AM均已接枝到聚丙烯中,并随接枝率增加相应峰面积增大,对水接触角(WCA)减小,亲水性明显改善。     

预辐照聚乙烯薄膜接枝丙烯酸/丙烯酰胺制备水凝胶互穿网络的研究

通过二次接枝方法，在预辐射聚乙烯(PE)薄膜上分别接枝丙烯酸(AAc)和丙烯酰胺(AAm)制得了具有pH敏感性和温度敏感性水凝胶互穿网络(IPN)。研究了不同辐照源、单体浓度、阻聚剂的浓度等对接枝率的影响，经测定，所得到的PE-g-Amn／AAc水凝胶膜具有明显的pH敏感性。     

基于响应面分析法的PVDF膜紫外接枝亲水改性的研究

采用非溶剂致相分离法制备了聚偏氟乙烯(PVDF)分离膜;以二苯甲酮为光引发剂,通过紫外接枝将亲水性单体丙烯酸(AA)和甲基丙烯酸-2-羟基乙酯(HEMA)接枝在PVDF膜表面。应用响应面分析法设计了紫外接枝实验,分别考察了单体浓度和紫外辐照时间对两种PVDF膜亲水改性效果的影响,优选出最佳工艺方案。AA接枝PVDF膜的最优方案:w(AA)为1.98%,辐照时间为40min,此时接枝膜的吸水率为109.95%。HEMA接枝PVDF膜的最优方案:w(HEMA)为1.5%,辐照时间为36.64min,接枝膜的吸水率为96.95%。     

紫外辐照接枝HEMA改性血液过滤用PBT无纺布的研究

研究了在紫外辐照条件下,以二苯甲酮(BP)为光敏剂,以甲基丙烯酸羟乙酯(HEMA)作为表面接枝物来改性血液过滤用聚对苯二甲酸丁二醇酯(PBT)无纺布,并对接枝改性后PBT进行了红外分析、扫描电镜观察、亲水性能测试.结果显示:红外图谱证实了HEMA在紫外辐照和光敏剂BP的引发条件下成功接枝到PBT 无纺布纤维表面,光敏剂...     

紫外辐射接枝改性UHMWPE纤维表面的研究

采用紫外辐射接枝方法对超高相对分子质量聚乙烯(UHMWPE)纤维表面进行改性。探讨了单体种类及浓度、引发剂、抗氧剂、接枝方法等对UHMWPE纤维表面处理效果的影响,测试了以其作为增强材料的复合材料的层间剪切强度。结果表明:在有氧开放体系下,气相接枝效果好于液相接枝;丙烯酰胺单体的接枝效果优于其它单体;接枝率随接枝单体浓度和接枝时间的增加而增加。采用丙烯酰胺为接枝单体,在光强度为86μW/cm~2条件下,对UHMWPE纤维进行紫外辐射接枝改性,按照一定铺层方式制备的环氧基复合材料的层间剪切强度从未处理的14.59MPa提高到17.36MPa。     

PP无纺布辐射接枝MMA的研究

采用聚丙烯(PP)无纺布为基材,甲基丙烯酸甲酯(MMA)为单体,~(60)Co-γ射线预辐射接枝共聚的方法制备接枝共聚物,讨论了辐射剂量、反应温度、反应时间、单体浓度、阻聚剂和交联剂的用量等对接枝率的影响。结果表明,接枝反应的最佳条件为:辐射剂量60 kGy以上、接枝温度65℃、接枝时间2 h、MMA质量分数20%、交联剂质量分数5%、阻聚剂用量0．3g,该条件下PP的接枝率为6．5%。     

微波辐射下淀粉-丙烯酰胺接枝共聚物的合成

以硝酸铈铵作为引发剂、丙烯酰胺为单体,用微波辐射法合成了淀粉接枝丙烯酰胺共聚物。探讨了反应时间、引发剂浓度、单体和淀粉质量比和反应温度等因素对接枝反应的影响。正交实验确定的最优工艺条件为:反应时间20 m in,引发剂浓度4 mmol/L,丙烯酰胺和淀粉质量比2.5∶1,反应温度55℃,最高接枝率和接枝效率分别达到211.6%和74.3%。     

Preparation of chlorinated poly(vinyl chloride)‐g‐poly(N‐vinyl‐2‐pyrrolidinone) membranes and their water permeation properties

Chlorinated poly(vinyl chloride) (CPVC) membranes for microfiltration processes were prepared with the combined process of a solvent evaporation technique and the water‐vapor induced‐phase‐inversion method. CPVC membranes with a mean pore size of 0.7 μm were very hydrophobic. These membranes were subjected to surface modification by ultraviolet (UV)‐assisted graft polymerization with N‐vinyl‐2‐pyrrolidinone (NVP) to increase their surface wettability and decrease their adsorptive fouling. The grafting yields of the modified membranes were controlled by alteration of UV irradiation time and NVP monomer concentration. The changes in chemical structure between the CPVC membrane and the CPVC‐g‐poly(N‐vinyl‐2‐pyrrolidinone) membrane and the variation of the topologies of the modified PVC membranes were characterized by Fourier transform infrared spectroscopy, gel permeation chromatography, and field emission scanning electron microscopy. According to the results, the graft yield of the modified CPVC membrane reached a maximum at 5 min of UV exposure time and 20 vol % NVP concentration. The filtration behavior of these membranes was investigated with deionized water by a crossflow filtration measurement. The surface hydrophilicity and roughness were easily changed by the grafting of NVP on the surface of the CPVC membrane through a simultaneous irradiation grafting method by UV irradiation. To confirm the effect of grafting for filtration, we compared the unmodified and modified CPVC membranes with respect to their deionized water permeation by using crossflow filtration methods. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3188–3195, 2003     

Zwitterionic sulfobetaine‐modified non‐woven fabric for blood filtration

Blood filtration requires a high removal ratio of leukocytes and with simultaneous high recovery ratio of platelets and other beneficial components. Problems are often encountered with blood filter materials in terms of high platelet loss. Zwitterions such as phosphorylcholine, sulfobetaine and carboxybetaine show effective resistance against protein adsorption and platelet adhesion. The study reported was aimed at achieving surface modification of poly(butylene terephthalate) non‐woven fabric (PBTNF) using UV radiation‐induced graft copolymerization of a zwitterionic sulfobetaine, N‐(3‐sulfopropyl)‐N‐methacroyloxyethyl‐N,N‐dimethylammonium betaine (SMDB), in order to improve the wettability and platelet recovery ratio of the PBTNF. Attenuated total reflection Fourier transform infrared and X‐ray photoelectron spectroscopy results showed that SMDB was successfully grafted onto the PBTNF. Photoinitiator concentration, monomer concentration and UV irradiation time affected markedly the degree of grafting. Critical wetting surface tension, water wetting time and hemolysis tests showed an improvement in wettability and blood compatibility as a result of graft copolymerization of SMDB. A blood filter material composed of SMDB‐modified PBTNF reduced platelet adhesion and had higher platelet recovery compared to poly(acrylic acid)‐modified PBTNF. It was found that SMDB monomer was successfully grafted onto PBTNF using UV radiation. The degree of grafting of SMDB could be controlled by varying the photoinitiator concentration, monomer concentration and UV irradiation time. SMDB‐modified PBTNF showed significant improvement in wettability and blood compatibility. The zwitterionic structure of SMDB is resistant to platelet adhesion. The SMDB‐modified PBTNF could be a candidate for a blood filter material and in other medical applications. Copyright © 2010 Society of Chemical Industry     

接枝法亲水改性腈纶的研究

采用两步法接枝共聚改性工艺实现腈纶织物亲水改性。通过探索溶胀剂、乳化剂、引发剂的种类和用量,以及活化预处理接枝共聚反应的工艺,确定接枝改性的最佳条件。结果表明:在溶胀剂氯苯7．0g／L, 乳化剂壬基酚聚氧乙烯醚(OP)2．1g／L,引发剂过氧化二苯甲酰(BPO)2．5g／L,亲水性酰胺类单体质量分数 2．0％,活化预处理温度75℃,活化时间30 min,接枝共聚反应温度85℃,反应时间60min,再经浓度为2．0g／ L碳酸钠溶液处理,腈纶织物的吸湿率达到7．0％。     

辐射接枝改性聚酯纤维吸湿性的研究

经间甲酚浸泡溶胀后,采用二苯甲酮(BP)的丙酮溶液浸泡,紫外光辐射接枝改性聚酯纤维的吸湿性,研究了辐射接枝条件对纤维回潮率的影响。结果表明:当溶胀剂质量分数为40%,溶胀时间为2.0 h,溶胀温度为60℃,BP丙酮溶液的浓度为0.20 mol/L、浸泡时间为1.0 h,紫外光照时间为2 0 h,丙烯酸浓度为0.58 mol/L时,聚酯纤维的回潮率由0.40%提高至3.04%。     

丙烯酸单体接枝纳米纤维素晶须的研究

以K2S2O8为引发剂,在纳米纤维素晶须(NCW)上接枝丙烯酸单体(AA),制备出丙烯酸接枝改性的纳米纤维素晶须.通过傅立叶变换红外光谱(FTIR)、透射电镜(TEM)、热重分析(TGA)等测试方法对接枝产物的性能进行了分析,并采用电导滴定的方法计算了接枝率以及表面取代基团含量.研究了反应条件对接枝率和接枝效率的影响.结果表明,在引发剂浓度为4 mmol/L,引发时间为5 min,纳米纤维素晶须与丙烯酸单体摩尔比为1: 1.5,反应时间为6 h的条件下,得到了接枝率为14.09%的丙烯酸接枝纳米纤维素晶须.实验证明,在NCW上可以接枝上丙烯酸,接枝率为14.09%的产物与NCW具有相似的表面形貌和热性能;TEM分析可知,接枝产物的分散性得到了提高;表面取代基团含量测试表明,接枝产物表面上的亲水性分散基团含量比NCW增加了5倍以上.     

Ultraviolet-initiated photografting of glycidyl methacrylate onto styrene–butadiene rubber

Photografting reaction onto styrene–butadiene rubber (SBR) as a function of monomer concentration, grafting method, irradiation time, and the carbon black content has been studied using ultraviolet (UV). Glycidyl methacrylate and benzophenone are used as monomer and initiator, respectively. The occurrence of graft reaction onto SBR surface is identified by infrared attenuated total reflection (IR-ATR) analysis. The degree of monomer graft increases with monomer concentration and tends to level off at high monomer concentration (>8.3M/L). Graft ratio also increases with UV irradiation time. Carbon black content is found as one of important factors that determine the monomer graft efficiency. The amount of monomer graft onto SBR decreases with increasing carbon black content and it is attributed to the reduction of irradiation absorbance due to the presence of carbon black. The occurrence of reaction between glycidyl methacrylate grafted SBR and nylon-6 via melt phase reaction is also identified using IR-ATR analysis. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1733–1739, 1999     

Gamma preirradiation and grafting of 2N-morpholino ethyl methacrylate onto polypropylene fabric

The radiation-induced grafting of 2N-morpholino ethyl methacrylate (MEMA) in aqueous solution onto polypropylene fabric by a preirradiation technique has been investigated. Among the most important factors affecting the graft yield are monomer concentration, irradiation dose, reaction temperature, and time. It was found that the graft yield increased with increasing monomer concentration, grafting temperature, and preirradiation dose. The kinetic studies showed that the dependence of the grafting rate on monomer concentration is of 1.1 order. Moreover, the calculated overall activation energy was 14.2 kcal/mol. The grafted PP fabric shows an increase in moisture regain with increasing graft yield. Also, the dyeability with acid dye was significantly increased due to grafting with MEMA. © 1995 John Wiley & Sons, Inc.