借助ATRP法合成两亲性星状多臂h-PCMS-g-mPEG接枝共聚物

以对氯甲基苯乙烯(CMS)为活性单体,CuCl/2,2'-联吡啶(bpy)为催化体系,通过原子转移自由基聚合反应(ATRP)合成具有不同结构特征的超支化聚对氯甲基苯乙烯(h-PCMS),分别考查了反应温度、反应时间对所合成的h-PCMS的组成结构、相对分子质量分布指数和转化率的影响。在NaH催化下,以不同支化度的h-PCMS与单甲氧基封端聚乙二醇(mPEG)进行醚化反应,制得以超支化大分子h-PCMS为疏水性核,以单甲氧基封端聚乙二醇(mPEG)为亲水性臂的两亲性星状多臂接枝共聚物h-PCMS-g-mPEG。采用红外光谱(IR)、凝胶色谱(GPC)、核磁共振氢谱(1H-NMR)及差示扫描量热仪(DSC)等技术对聚合物的结构和性能进行表征。     

聚乙烯醇基相变储能材料的制备与表征

相变储能材料能够解决能量储存和释放在时间和空间上的矛盾,被广泛应用于储热技术。以聚乙烯醇(PVA)和聚乙二醇单甲醚(mPEG)为原料,制备PVA/mPEG接枝聚合物和PVA+mPEG共混聚合物,并讨论不同相变剂mPEG分子量及添加量对PVA/mPEG接枝聚合物的化学结构及相变储能的影响。利用差示扫描量热仪(DSC)对PVA/mPEG接枝聚合物和PVA+mPEG共混聚合物进行表征。结果表明:随着mPEG含量的增加,PVA/mPEG接枝聚合物的相变焓和相变温度升高。随着mPEG分子量的增加,PVA/mPEG接枝聚合物的熔点和相变焓显著提高。PVA/mPEG接枝聚合物的稳定性优于PVA+mPEG共混聚合物。结合相变材料的力学性能,当mPEG的添加量为PVA的3%、mPEG分子量为1 000时,制备的PVA/mPEG接枝聚合物的性能较优异。     

聚乙二醇链段键接方式对氨基聚醚-环氧树脂阻尼性能的影响

α-甲氧基-ω-N-异丙醇基-对苯甲胺基聚乙二醇(PO-p-MPEGBA)和酚醛环氧树脂F51反应制备了PEG接枝环氧树脂化合物(PEGF51)。用红外光谱和凝胶渗透色谱(GPC)分析了PEGF51的结构,通过动态力学性能测试研究了聚乙二醇链段分子量(PEM)以及在环氧树脂交联网络中的键接方式对聚合物动态力学性能的影响规律。结果表明,将PEG链段以化学键接的方式引入到环氧树脂交联网络中制备了接枝型聚合物(PEGF51/m-XDA)和交联型聚合物(F51-PMAPEG)。发现PEG链段以支链的方式悬挂于环氧树脂交联网络结构中,PEGF51/m-XDA接枝型聚合物的阻尼性能得到明显提高。PEM=800时,PEG接枝型聚合物阻尼因子(tanδ)≥0.3的有效阻尼温域达到52℃。     

丙烯腈接枝三元乙丙橡胶共聚物增容三元乙丙橡胶/丁腈橡胶共混胶的性能

采用溶液接枝聚合法制备了丙烯腈（ACN）接枝三元乙丙橡胶（EPDM）共聚物（PAN-gEPDM）,考察了其接枝率及用量对EPDM/丁腈橡胶（NBR）共混胶物理机械性能和耐油性能的影响,并表征了PAN-g-EPDM及其增容EPDM/NBR共混胶。结果表明,ACN单体与EPDM主链发生了接枝反应,得到了不同接枝率的PAN-g-EPDM,其具有不同的热分解温度和玻璃化转变温度;当加入6份接枝率为26%的PAN-g-EPDM时,共混胶的物理机械性能及耐油性能较佳;PAN-g-EPDM可起到增容作用,使NBR相和EPDM相的相容性得到改善。     

醚化淀粉接枝丙烯酰胺絮凝剂的制备及性能

以 2,3- 环氧丙基三甲基氯化铵（GTA）为醚化剂半干法制备阳离子醚化淀粉（St-GTA）,采用反相乳液聚合法制备醚化淀粉接枝丙烯酰胺絮凝剂（St-GTA-PAM）。以单体转化率和接枝率为指标,探究制备条件对 St-GTA-PAM 的影响。结果表明,反相乳液聚合法最佳条件为：乳化剂添加量 2.0m L,St-GTA 与 AM 单体比1∶3.5,KPS 浓度 6mmol·L^-1,反应温度 60℃,此时单体转化率为 95.4%,接枝率为 87.5%。利用红外光谱、扫描电镜与热重分析对絮凝剂进行性能表征,并通过高岭土模拟废水絮凝实验确定 St-GTA-PAM 的最佳使用条件。结果显示,在最佳投加量 250mg·L^-1时,St-GTA-PAM 絮凝率可达 93.9%,在水温 10～50℃和 pH 值为 4～10 条件下,絮凝剂适用性好。     

环氧含氟聚合物对棉纤维的改性及其超疏水／疏油表面性能研究

采用自由基聚合法合成聚（甲基丙烯酸缩水甘油醚-无规-聚乙二醇甲基丙烯酸甲酯）[P（GMA-r-mPEGMA）],然后将其中的部分环氧基团与十七氟硫醇中的巯基通过点化学反应,接枝上十七氟硫醇单体（Perfluorodecanethiol,PFDT）,制备成环氧含氟聚合物聚（甲基丙烯酸缩水甘油醚-无规-聚乙二醇甲基丙烯酸甲酯）-接枝-十七氟硫醇[P（GMA-r-mPEGMA）-g-PFDT]。利用自组装方法将环氧含氟聚合物制备成水分散纳米胶束溶液,将棉纤维浸渍到该水分散纳米胶束溶液中,加入2-乙基-4-甲基咪唑作为潜伏性促进剂,促进聚合物的环氧基团与棉纤维表面的羟基活性基团反应,将含氟聚合物通过化学接枝法键合到纤维表面。将改性棉纤维烘干,使含氟基团迁移到表面,制备成超疏水／疏油效果的棉纤维表面,其水接触角度可达到165°以上,滚动角度小于5°,食用油接触角在130°以上,且由于环氧基团的强有力粘接性,使得该改性棉纤维具有很好的稳定性,具有良好的耐有机溶剂抽提、耐酸碱、耐水洗、耐超声等优良性能。     

壳聚糖/N-乙烯基吡咯烷酮接枝共聚物的制备及其性能

以壳聚糖（CS）和N-乙烯基吡咯烷酮（NVP）为原料,本文采用过氧化氢和抗坏血酸共引发剂引发,制备壳聚糖/N-乙烯基吡咯烷酮的接枝共聚物（CS-g-NVP）,研究了引发剂配比、反应温度和反应时间等因素对接枝共聚反应的影响。通过红外光谱、核磁共振和热重分析等对产物进行表征,并考察其吸湿性和亲水性能。结果表明,接枝共聚反应的最佳条件为：引发剂抗坏血酸/过氧化氢的摩尔比为1∶1、反应温度60℃、反应时间12h。接枝共聚产物的吸湿性优于壳聚糖,在饱和氯化钙和饱和硫酸铵环境下产物的吸湿率分别为3.68%和23.1%,高于原料壳聚糖的0.41%和9.77%,产物具有良好的亲水性和水溶性,能溶解于酸性和碱性水溶液中。     

PLA/POE-g-GMA共混物的制备及性能研究

采用熔融反应法制备乙烯-辛烯共聚物（POE）接枝甲基丙烯酸缩水甘油酯（GMA）（POE-g-GMA）,实现POE反应的官能化,通过反应共混的方法制备聚乳酸（PLA）/POE共混物,考察了POE和POE-g-GMA对PLA的力学性能和热性能及微观形态的影响。结果表明：POE-g-GMA要有适当的接枝率,增韧效果才显著,用0.6%～0.8%接枝率的POE-g-GMA增韧PLA,当POE-g-GMA质量分数达到20%时,共混物的缺口冲击强度提高到基体PLA的6倍左右;同时材料的热性能基本不受影响。POE与PLA间相容性不好,接枝后与PLA间相容性得到改善。     

聚苯乙烯接枝聚乙二醇6000的制备及表征

以1,4-二氯甲氧基丁烷为氯甲基化试剂,通用级聚苯乙烯(PS)为原料,制备了氯甲基化聚苯乙烯(CMPS);将CMPS与聚乙二醇(PEG)6000采用碱催化法制备了PS接枝PEG6000聚合物(PEG6000-g-PS)。对CMPS,PEG6000-g-PS进行傅里叶变换红外光谱分析、X射线光电子能谱分析,对PS,PEG,PEG6000-g-PS进行差示扫描量热法分析、热重分析。结果表明:成功制备了PEG6000-g-PS,且接枝率为12.3%;PEG6000-g-PS的熔融温度为63.03℃,相变焓为15.313 J/g,起始分解温度为314℃,热稳定性良好。     

PAM-g-PVA/MWCNTs导电复合材料的制备及表征

以硝酸铈胺-PVA为氧化还原引发体系,制备了丙烯酰胺接枝聚乙烯醇（PAM-g-PVA）聚合物,采用共混法,在接枝聚合物中掺杂多壁碳纳米管制备了PAM-g-PVA/MWCNTs气敏传感导电薄膜材料,研究了在不同饱和蒸气中的气敏响应性。结果表明,导电薄膜在乙酸乙酯、正丙醇饱和有机溶剂蒸气中显示负蒸气系数效应（NVC）,在丙酮和盐酸饱和蒸气中为正气系数效应（PVC）,但随着电阻的增加,导电薄膜在盐酸饱和蒸气中呈现负蒸气系数效应。     

Preparation,characterization, and properties of cellulose–polyacrylamide graft copolymers

Graft copolymers of acrylamide on cellulose materials (α‐cellulose 55.8%, DP 287.3) obtained from Terminalia superba wood meal and its carboxymethylated derivative (DS 0.438) were prepared using a ceric ion initiator and batch polymerization and modified batch polymerization processes. The extent of graft polymer formation was measured in graft level, grafting efficiency, molecular weight of grafted polymer chains, frequency of grafting as a function of the polymerization medium, and initiator and monomer concentrations. It was found that the modified batch polymerization process yielded greater graft polymer formation and that graft copolymerization in aqueous alcohol medium resulted in enhanced levels of grafting and formation of many short grafted polymer chains. Viscosity measurements in aqueous solutions of carboxymethyl cellulose‐g‐polyacrylamide copolymer samples showed that interpositioning of polyacrylamide chains markedly increased the specific viscosity and resistance to biodegradation of the graft copolymers. The flocculation characteristics of the graft copolymers were determined with kaolin suspension. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 913–923, 2003     

Graft polymerization of vinyl acetate onto starch. Saponification to starch–g–poly(vinyl alcohol)

Graft polymerizations of vinyl acetate onto granular corn starch were initiated by cobalt-60 irradiation of starch-monomer-water mixtures, and ungrafted poly(vinylacetate) was separated from the graft copolymer by benzene extraction. Conversions of monomer to polymer were quantitative at a radiation dose of 1.0 Mrad. However, over half of the polymer was present as ungrafted poly-(vinyl acetate) (grafting efficiency less than 50%), and the graft copolymer contained only 34% grafted synthetic polymer (34% add-on). Lower irradiation doses produced lower conversions of monomer to polymer and gave graft copolymers with lower % add-on. Addition of minor amounts of acrylamide, methyl acrylate, and methacrylic acid as comonomers produced only small increases in % add-on and grafting efficiency. However, grafting efficiency was increased to 70% when a monomer mixture containing about 10% methyl methacrylate was used. Grafting efficiency could be increased to over 90% if the graft polymerization of vinyl acetate-methyl methacrylate was carried out near 0°C, although conversion of monomers to polymer was low and grafted polymer contained 40-50% poly(methyl methacrylate). Selected graft copolymers were treated with methanolic sodium hydroxide to convert starch–g–poly(vinyl acetate) to starch–g–poly(vinyl alcohol). The molecular weight of the poly(vinyl alcohol) moiety was about 30,000. The solubility of starch–g–poly(vinyl alcohol) in hot water was less than 50%; however, solubility could be increased by substituting either acid-modified or hypochlorite-oxidized starch for unmodified starch in the graft polymerization reaction. Vinyl acetate was also graft polymerized onto acid-modified starch which had been dispersed and partially solubilized by heating in water. A total irradiation dose of either 1.0 or 0.5 Mrad gave starch–g–poly(vinyl acetate) with about 35% add-on, and a grafting efficiency of about 40% was obtained. A film cast from a starch–g–poly(vinyl alcohol) copolymer in which homopolymer was not removed exhibited a higher ultimate tensile strength than a comparable physical mixture of starch and poly(vinyl alcohol).     

Amylose graft polymers made by 60Co gamma-irradiation

Model products were needed to elucidate structure–property relationships in a starch graft polymer research program. Simultaneous irradiation of amylose and acrylamide in oxygen-free, dilute aqueous solutions gave graft polymers with maximum add-on of about 16%. The graft polymers were separated from homopolymer and subfractionated by incremental additions of nonsolvent (methyl or ethyl alcohol) to irradiated aqueous reaction media. The graft polymers were fairly homogeneous in graft content. Effects were determined of ratios of monomer to substrate, dose rate, and total dose on yield, graft content, intrinsic viscosity, and homopolymer characteristics. Under some conditions, crosslinks probably formed between graft side chains. Large differences in solution properties of a synthetic mixture of separately irradiated amylose and acrylamide and an irradiated solution of amylose and acrylamide indicated that grafting had occurred. Further evidence for true grafting was based on the action of a selective precipitant, n-butyl alcohol, on graft polymer solutions.     

溶液法制备POE-g-MAH及其影响因素

采用溶液接枝法,以过氧化二异丙苯(DCP)为引发剂,马来酸酐(MAH)为单体,制备了POE-g-MAH。通过红外光谱确定了接枝物的结构,采用酸碱滴定法测定了产物的接枝率,详细研究了POE、MAH、DCP用量及反应温度等对接枝率的影响规律。结果表明,当POE∶MAH∶DCP为13∶6∶1、反应温度为150℃、反应时间5h时接枝率达到最大值9.5%。     

马来酸酐接枝SBS的研究

以过氧二苯甲酰（ＢＰＯ）为引发剂,用溶液法合成马来酸酐（ＭＡＨ）接枝ＳＢＳ的聚合物ＳＢＳ－ｇ－ＭＡＨ,讨论了ＭＡＨ和ＢＰＯ的用量及其反应条件对接枝率的影响,并用红外光谱表征了ＳＢＳ－ｇ－ＭＡＨ结构     

两亲性接枝共聚物PVA-g-PBA的合成与表征

以过硫酸钾 (KPS)为引发剂 ,将丙烯酸丁酯 (BA)接枝到聚乙烯醇 (PVA)上 ,制得两亲性接枝共聚物 PVA-g-PBA。用红外光谱、X射线衍射表征了接枝物 ,研究了引发剂浓度、单体浓度及反应时间对单体转化率、接枝率和接枝效率和接枝率对共聚物吸水性能的影响。结果表明在水介质中 ,氮气保护下 ,70℃时 ,以过硫酸钾 (KPS)为引发剂 ,将丙烯酸丁酯 (BA)接枝到聚乙烯醇 (PVA)上 ,[PVA]为 2 .5× 1 0 -4mol/ L,[BA]为 0 .63 mol/ L、[KPS]为 5 .5 5× 1 0 -4时 ,反应 5 h,能获得较高 CM、G和 Ge的接枝物。接枝物的接枝率越高 ,吸水率越低 ,吸水 1 0 h达平衡 ,最大平衡吸水率为 1 88.8%。     

水悬浮体系中苯乙烯和马来酸酐接枝聚丙烯改性研究

采用过氧化苯甲酰（BPO）为引发剂,通过水相悬浮法制备苯乙烯（St）和马来酸酐（MAH）双单体接枝聚丙烯（PP-g-St/MAH）。考察St加入量对接枝反应的影响,通过熔体流动速率和水接触角测试分析接枝产物的性能,采用X射线衍射和红外光谱分析表征接枝产物的结构。结果表明,随St加入量的增加,MAH接枝率升高,在St/MAH为3/1时,MAH接枝率为3.10 %,接枝效率高达70.02 %。随着接枝率的增加,接枝产物的熔体流动速率减小,PP主链间相互缠绕作用增强,熔体强度增大,结晶度降低,亲水性改善。     

A new biodegradable polymer: PEGylated chitosan-g-PEI possessing a hydroxyl group at the PEG end

The heterobifunctional polyethylene glycol (PEG) was synthesized by a facile and an efficient synthetic route. A new biodegradable graft copolymer of chitosan-g-PEI-g-PEG-OH possessing a hydroxyl group at the PEG chain end was prepared by the method of grafting reaction between chitosan, polyethylenimine (PEI) and heterobifunctional PEG for constructing amphiphilic copolymers. The amphiphilic and end-functionalized copolymer may have a potential utility in conjugating with targeting moieties for targetable gene or drug delivery.     

Graft copolymerisation of vinyl monomers on modified cottons. VII. Grafting by chain transfer

Grafting of methyl methacrylate on cellulosic materials by chain transfer under the catalytic influence of azobisisobutyronitrile (AIBN) was extensively studied. The graft yield is influenced by reaction time, temperature, monomer and initiator concentration, reaction medium and nature of the substrate. In general, the grafting reaction shows an induction period after which the polymerisation proceeds rapidly. The graft yield increases and the induction period decreases by rising the reaction temperature from 50 to 70°C. This is also the case when the monomer concentration was increased from 2 to 6%. Increasing the AIBN concentration up to 0.01 M causes a significant enhancement in grafting while further increase brings about a marked fall in the graft yield. Among the reaction media studied, a water/solvent mixture containing 25% of either methanol, ethanol, propanol, butanol or acetone seems to constitute a reaction medium where the monomer and initiator are completely miscible and the swelling of cellulose by water is not hindered by the presence of these solvents. Increasing the solvent ratio in the water/solvent mixture causes a considerable decrease in the graft yield. The polymer content of the cellulosic materials, i. e. the graft yield, follows the order: partially carboxymethylated cotton > cotton treated with 12N sodium hydroxide > cyanoethylated cotton > cotton treated with 0.5 N sodium hydroxide > purified cotton. In addition, proof of grafting was provided by the fractional precipitation method.     

聚乙烯固相接枝马来酸酐的研究

研究了以过氧化苯甲酰（ＢＰＯ）为引发剂,二甲苯为界面剂,粉状聚乙烯（ＨＤＰＥ、ＬＬＤＰＥ）固相接枝马来酸酐（ＭＡＨ）的反应。讨论了反应温度、引发剂用量、单体用量和界面剂种类等对接枝反应的影响,并用红外光谱法证实了接枝反应。结果表明,ＰＥ固相接枝ＭＡＨ反应对温度敏感,随温度升高,接枝率提高;在一定范围内,接枝率随引发剂用量、单体用量和搅拌转速、界面剂用量的增加而提高;界面剂用量虽少,但能促进ＢＰＯ、ＭＡＨ在ＰＥ上的反应。通过接枝反应可得到接枝率为９％左右的ＰＥ－ｇ－ＭＡＨ产物和接枝率为１３％以上的ＬＬＤＰＥ－ｇ－ＭＡＨ产物