共查询到18条相似文献,搜索用时 125 毫秒
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两亲性接枝共聚物PVA-g-PBA的合成与表征 总被引:3,自引:0,他引:3
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%。 相似文献
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以过硫酸铵为引发剂,在玉米淀粉上接枝共聚丙烯酸丁酯(BA)和乙酸乙烯酯(Vac)制备乳液状淀粉基胶黏剂.采用L9(34)正交实验,考察了引发剂的浓度、反应时间、单体的体积比和PVA用量对木材胶黏剂的剪切强度的影响.用极差法分析出的各因素的影响程度大小顺序是:引发剂的浓度>单体的体积比>PVA用量>反应时间.实验确定的最佳反应条件是:过硫酸铵2.0mol/L,温度为75℃,反应时间4h,Vac:BA=6:4,PVA浓度为0.15mol/L.制得淀粉基胶黏剂,不需要添加任何助剂,可直接用于粘接木材. 相似文献
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聚苯乙烯溶液接枝改性研究 总被引:1,自引:1,他引:0
研究了丙烯酸丁酯(BA)、聚苯乙烯(PS)的二甲苯溶液,以过氧化二苯甲酰(BPO)为引发剂制备聚苯乙烯/丙烯酸丁酯接枝物的溶液接枝反应.讨论了接枝对聚苯乙烯性能的影响以及反应单体浓度、引发剂用量等因素对接枝率的影响. 相似文献
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以球形纤维素珠体为原料,丙烯腈(AN)和丙烯酰胺(AM)为单体,硝酸铈铵和过硫酸钾(KPS)为引发剂,制备纤维素珠体-AN-AM接枝共聚物,并通过正交单因素实验,研究了反应温度、引发剂用量、单体用量、反应时间等因素对接枝效果的影响。实验结果表明:当反应温度为60℃,引发剂硝酸铈铵用量为20%,KPS用量为15%(引发剂与单体AN的质量百分比),单体AN浓度为0.75 mol/L,AM浓度为0.28 mol/L,硝酸浓度为0.14 mol/L,反应时间为3 h时,接枝效果最好。此条件下,AN、AM与纤维素的接枝率可达259.4%,接枝效率可达49.40%。 相似文献
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甲基丙烯酸与壳聚糖接枝共聚物的制备及应用研究 总被引:20,自引:1,他引:19
以硝酸铈铵 -乙二胺四乙酸 (CAN -EDTA)为引发剂 ,研究了壳聚糖与甲基丙烯酸 (MAA)的接枝共聚反应。当c (CAN) =6 5mol/L ,c (EDTA) =3 3mol/L ,ρ(MAA) =2 0g/L ,ρ(壳聚糖 ) =5g/L ,在 5 0℃反应 2 5h ,壳聚糖接枝率、单体转化率较高。用红外光谱 (FTIR)表征了接枝共聚物。以接枝共聚物为载体制备了药物非诺落芬钙缓释片剂 ,通过测定药物片剂的非诺落芬钙在人工肠液的释放速率 ,表明药物片剂的非诺落芬钙有缓释作用。 相似文献
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以皮革废弃物提取的明胶为原料,丙烯酰胺(AM)、丙烯酰氧乙基三甲基氯化铵(DAC)和丙烯酸丁酯(BA)为单体[n(AM)∶n(DAC)∶n(BA)=80∶18∶2],叔丁基过氧化氢和焦亚硫酸钠为引发剂,接枝共聚合成了疏水改性阳离子胶原蛋白絮凝剂P(C-AM-DAC-BA)。以絮凝剂对油田模拟废水浊度的去除率为指标,探讨了明胶与单体的质量比、引发剂浓度、接枝温度、接枝时间对絮凝效果的影响。通过响应面法优化得到了P(C-AM-DAC-BA)接枝共聚最佳条件为m(明胶)∶m(单体)=1∶2.04、引发剂浓度0.032 mol/L、接枝温度49℃、接枝时间2.8 h。在该条件下,P(C-AM-DAC-BA)对油田模拟废水浊度去除率为91.5%。 相似文献
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Methyl methacrylate (MMA) was graft polymerized onto polyvinyl alcohol (PVA) using ceric ammonium sulfate as an initiator in aqueous medium. The grafting efficiency of MMA was studied as a function of monomer and initiator concentration, time, pH, and temperature. Grafting efficiency was found to be optimum at a particular level of ceric ammonium sulfate (3.16 × 10−3 mol L−1), PVA (1.0 g L−1), MMA (0.469 mol L−1), H2SO4 (0.188 mol L−1), temperature (45°C), and time (4 h). The probable reasons for the influence of reaction variable on the observed trend of MMA towards grafting have been discussed. Acid hydrolysis and infrared spectroscopy were used for the confirmation of graft copolymer formation. Thermogravimetric analysis of PVA and a representative graft copolymer were studied. The solubility/swellability and the gelatinization characteristics are also reported. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 523–527, 1998 相似文献
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Graft reaction of acrylamide (AM) and 4‐vinyl pyridine (4‐VP) onto ultra‐low molecular weight poly(vinyl alcohol) by ceric (IV) ion initiation had been systematically investigated; and the graft conditions were optimized by studying the effect of monomer/initiator concentration, solvents composition, reaction time and temperature. At optimized conditions, the maximum grafting efficiency and grafting ratio was ~ 50% and 51%, respectively with the presence of AM, whereas they decreased to 19% and 23%, respectively, without the presence of AM. Thermogravimetric analysis showed that as‐resulted graft copolymer had a lower thermal stability than homopolymer PVA. FTIR and 1H‐NMR confirmed chemical structure of as‐synthesized graft copolymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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Yinghai Liu Xiaohui Liu Yuanwei Liu Jinsong Zhang Kuilin Deng Zhanjun Liu 《Polymer International》2004,53(11):1611-1616
The graft copolymerization of methyl acrylate onto poly(vinyl alcohol) (PVA) using potassium diperiodatoargentate(III) [Ag(III)]–PVA redox system as initiator was studied in an alkaline medium. Some structural features and properties of the graft copolymer were confirmed by Fourier‐transfer infrared spectroscopy, scanning electron microscope, X‐ray diffraction and thermogravimetric analysis. The grafting parameters were determined as a function of concentrations of monomer, initiator, macromolecular backbone (X?n = 1750, M? = 80 000 g mol?1), reaction temperature and reaction time. A mechanism based on two single‐electron transfer steps is proposed to explain the formation of radicals and the initiation profile. Other acrylate monomers, such as methyl methacrylate, ethyl acrylate and n‐butyl acrylate, were also used to produce graft copolymerizations. It has been confirmed that grafting occurred to some degree. Thermogravimetric analysis was performed in a study of the moisture resistance of the graft copolymer. Copyright © 2004 Society of Chemical Industry 相似文献
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Polypropylene (PP) was modified by solid‐phase graft copolymerization with maleic anhydride (MAH) and styrene (St), using benzoyl peroxide as the initiator and xylene as the interfacial agent. Effects of various factors such as monomer concentration, monomer ratio, initiator concentration on grafting percentage, and acid value were investigated. The graft copolymer was characterized by Fourier transform infrared, pyrolysis gas chromatography—mass spectroscopy, and dynamic mechanical analysis, and the intrinsic viscosity of the extractive from the reaction product was investigated. The results showed that the grafting percentage and acid value of the graft copolymer of PP with two monomers (MAH and St) were considerably higher than those of the graft copolymer of PP with MAH alone. The graft segments were shown to be the copolymer of St and MAH with a substantial molecular weight. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2482–2487, 2000 相似文献
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