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以马来酸酐为单体、过氧化物为引发剂,采用熔融挤出法制备了乙烯-醋酸乙烯酯共聚物接枝马来酸酐(EVA-g-MAH)。重点讨论了不同型号的EVA、过氧化物引发剂品种及用量、单体MAH用量和加工工艺条件等因素时接枝反应的影响。通过化学滴定法和傅立叶红外光谱法(FTlR)证实部分马来酸酐确实以化学键连接到EVA分子链上。与聚乙烯(PE)、聚丙烯(PP)相比,EVA中由于含有醋酸乙烯(VA)基团,极性较大,与MAH的相客性较好,因而在相同的条件下接枝效率也更大;而且VA含量越大,越有利于接枝反应。比较不同的过氧化物引发剂BPO和DCP。发现DCP的引发效果更好。实验结果还表明,在EVA进行接枝反应的同时存在着交联反应,引发剂DCP的用量不宜过高,为得到接枝率适中,交联度很小的接枝产物,还要选择合适的MAH与DCP的用量。 相似文献
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悬浮溶胀法合成接枝聚丙烯 总被引:10,自引:1,他引:9
用BPO作引发剂以水相悬浮胀法合成接枝聚丙烯,研究了反应条件、组分等因素对PP的接枝率(Gr)和接枝效率(Ge)的影响,发现溶胀剂、悬浮剂、引发剂、催化剂是该接枝物的主要影响因素。用此方法接枝的聚丙烯有工艺简单,接枝率高,聚丙烯降解程度小等优点,用它作PP/CaCO3、PP/PA6、PP/MBS体系的相容剂,测试结果表明,复合材料的力学性能有很大的提高。 相似文献
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采用硝酸铈铵-纤维素纤维氧化还原体系引发丙烯酰胺在粘胶纤维上接枝共聚反应,探讨了引发剂浓度、体系硝酸浓度、单体比、反应温度和时间诸因素对产物平衡接枝率的影响及接枝共聚机理,IR表征产物具有预期的结构。 相似文献
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马来酸酐接枝天然橡胶的制备及应用研究 总被引:1,自引:0,他引:1
以过氧化二异丙苯(DCP)为引发剂,在转矩流变仪中以马来酸酐(MAH)单体对天然橡胶(NR)进行接枝改性。通过傅里叶变换红外光谱对接枝物进行了定性表征;采用化学滴定法测定了反应产物中MAH的接枝率和接枝效率。研究了MAH单体用量、DCP用量、反应温度、转子转速等因素对反应产物接枝率和接枝效率的影响,研究结果表明,以转矩流变仪作为反应器,NR为100份(质量份数,以下同此),MAH和DCP分别为5份、0.75份,温度为130℃,转子转速为50 r/min的条件下反应3min,产物接枝率和接枝效率较高,分别为1.45%和30.63%。将所制备的马来酸酐接枝天然橡胶(NR-g-MAH)应用于尼龙短纤维增强天然橡胶复合材料(NR/SF)体系中,可有效改善尼龙短纤维与NR基体间的界面结合。 相似文献
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采用溶液法制备了马来酸酐接枝聚丙烯。采用单因素及正交实验方法研究了单体、引发剂用量、反应温度、反应时间、溶剂用量及引发剂加入工艺等因素对产物接枝率的影响。结果表明,各因素对聚丙烯接枝率都有一定的影响,马来酸酐及二甲苯的用量对聚丙烯接枝率影响最大,当马来酸酐、二甲苯与聚丙烯之间比例为0.1/2/1时,聚丙烯的接枝率最大,接枝率可达4.36%。 相似文献
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采用固相接枝法合成低密度聚乙烯(LDPE)接枝丙烯酸-2-羟乙酯(HEA)共聚物(LDPE-g-HEA),利用傅里叶变换红外光谱(FTIR)分析了接枝产物结构。实验考察了溶胀时间、溶胀温度、反应时间、反应温度、引发剂偶氮二异丁腈(AIBN)浓度、界面剂二甲苯和单体用量对接枝反应的影响,并对不同单体投料量下制备的接枝产物进行凝胶含量测定。结果表明,HEA接枝到了LDPE主链上;在50℃溶胀40 min后,偶氮二异丁腈(AIBN)含量0.3%,二甲苯含量8.6%,85℃下反应2.5 h的较佳反应工艺条件下,当HEA加入量5.0%时,接枝率为3.8%,接枝效率达76.6%,凝胶含量为2.2%。随单体投料量的增加接枝率和接枝效率增大,产物的凝胶含量升高,可以通过调控单体投料量制备不同接枝率的改性产物。 相似文献
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以玉米淀粉和丙烯酰胺为原料,过硫酸铵为引发剂,用水溶液聚合法合成了淀粉接枝丙烯酰胺絮凝剂。研究了反应温度、反应时间和引发剂用量等反应条件对单体转化率、接枝率、接枝效率、絮凝性能的影响。结果表明:在淀粉与丙烯酰胺单体的质量比为1∶2,反应温度为45℃,反应时间为3h,引发剂用量为单体的1.25%时,产物接枝效率、单体转化率、接枝率最高,絮凝性能较优。 相似文献
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聚苯乙烯溶液接枝改性研究 总被引:3,自引:0,他引:3
用溶液接枝的方法研究了回收的废聚苯乙烯泡沫塑料的接枝工艺,包括引发剂的用量、反应温度、单体浓度、单体种类、多单体共接枝对废聚苯乙烯泡沫塑料接枝的影响。PS接枝工艺的研究结果为废聚苯乙烯泡沫塑料的再利用提供了理论依据。 相似文献
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Poly(ester urethane) (PU) with functional groups (amide, hydroxyl, carboxyl) on surfaces were prepared by grafting monomers such as acrylamide (AAm), hydroxyethyl acrylate (HEA), and methacrylic acid (MAA) onto the PU membranes. Grafting copolymerization was carried out by the combined use of photooxidization and UV irradiation grafting. The PU membrane was photooxidized in hydrogen peroxide solution under UV light to yield hydroperoxide groups on the surface and then irradiation grafting with monomer in water. The ATR‐FTIR spectrum, X‐ray photoelectron spectroscopy characterized the grafted copolymers and verified the occurrence of grafting copolymerization. The results showed that the content of hydroperoxide groups yielded was dependent on the photooxidization time and reached maximum at about 8 h. Grafting copolymerization was enhanced when irradiating by UV light. The degree of grafting was increased with the increase of content of hydroperoxide groups, irradiation time, and monomer concentration. The grafting copolymerization was enhanced when an appropriate amount of ferrous ions was added. After grafting, the wettability of PU and the water absorption percentage increased with the degree of grafting. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2505–2512, 2000 相似文献
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The effect of time, temperature, the concentration of initiator and emulsifier, and the ratio of starting polymer to monomer on the degree of conversion (MC) of styrene and the grafting efficiency (GE) of polystyrene has been investigated. The reaction was initiated with potassium persulphate. It has been found that the degree of conversion of styrene and the grafting efficiency change in opposite directions when plotted as functions of the reaction parameters studied. The graft copolymerization is assisted by short reaction times and weight ratios of poly(butyl acrylate) to styrene greater than unity. The results obtained suggest that higher grafting efficiencies are obtained when the concentration of emulsifier is below its c.m.c. (critical micellar concentration) value. When using two different anionic emulsifiers it has been observed that the effect of initiator concentration on the degree of conversion of styrene and the grafting efficiency is complicated. Both the quantities studied (MC and GE) exhibit extrema in the range of initiator concentration studied (3.7?33.3 × 10?5 mol dm?3 of H2O). No meaningful effect of temperature in the range 60°–90°C or that of dodecyl mercaptan (molecular weight regulator) used in an amount 0–0.4% in relation to poly(butyl acrylate) and styrene has been observed on the MC and GE values. 相似文献
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高锰酸钾引发双水相中淀粉接枝丙烯酰胺共聚反应 总被引:2,自引:0,他引:2
在双水相中进行淀粉接枝丙烯酰胺共聚反应是一种新的聚合方法,对以聚乙二醇为分散介质、高锰酸钾为引发剂的双水相中淀粉接枝丙烯酰胺共聚反应进行了研究,考察了引发时间、引发剂浓度及配比对产品单体转化率、接枝率和接枝效率的影响。通过实验得到聚合反应的最佳工艺条件:引发时间为10 min,n(高锰酸钾)∶n(丙烯酰胺)=3.0×10-4∶1,n(高锰酸钾)∶n(H+)=1∶10,反应温度为50℃,反应时间7 h,此时得到的产品的单体转化率C为98.88%,接枝率G为144.53%,接枝效率GE为97.81%。最后通过红外光谱仪进行结构表征。 相似文献
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Graft copolymerization of styrene (St) and methyl methacrylate (MMA) in the presence of natural rubber latex using cumene hydroperoxide/tetraethylenepentamine redox initiator system was prepared at various process variables. The synthesized graft copolymers were purified and then characterized by Fourier transformed infrared spectroscopy analysis. A full 24 factorial experimental design was applied to study the effect of various process variables on grafting efficiency. The following four independent variables considered to be mainly affecting the grafting efficiency were reaction temperature, rubber‐to‐monomer ratio, St‐to‐MMA ratio, and initiator amount used in the secondary polymerization. It was shown in this study that the reaction temperature significantly influenced the grafting efficiency, increasing as the temperature was increased. The amount of grafting increased with increasing rubber‐to‐monomer ratio and St‐to‐MMA ratio, whereas the amount of grafting decreased with increasing amount of initiator. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 455–463, 2004 相似文献
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Kinetic study on free radical grafting of polyethylene with acrylic acid by reactive extrusion
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In the reactive extrusion process for the free radical grafting of acid monomers onto polyethylene, monomer grafting and homopolymerization occur simultaneously and interact with each other. Using an incremental theory, mathematical models of conversions for monomer grafting and homopolymerization were separately constructed to predict the grafting degree, mass of homopolymer and grafting efficiency. Effects of the barrel temperature, initial monomer and initiator concentrations on grafting behaviors were investigated. The barrel temperature and initial monomer concentration were shown to be the main process parameters for controlling the grafting degree. The grafting degree and mass of homopolymer increased significantly with increasing barrel temperature and monomer concentration and increased marginally with increasing initiator concentration. No significant improvement in the grafting efficiency was observed. The predictions of the models are in good agreement with experimental data. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40990. 相似文献
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采用半连续种子乳液接枝聚合枝术,在聚丁二烯乳胶粒子上接枝共聚苯乙烯,合成了聚丁二烯接枝聚苯乙烯(PB-g-PS)接枝共聚物。研究了合成工艺条件对接枝共聚反应的影响,实验结果表明,苯乙烯在聚丁二烯橡胶粒子上的接枝效率和接枝度随聚丁二烯对苯乙烯质量比的增加而降低,随反应温度的增加而增加,随引发剂浓度的增加呈先增加后降低的变化趋势,接枝效率随单体滴加时间的增加而增加,接枝度则呈先增加后降低的变化趋势。利用FTIR和1H-NMR对PB-g-PS接枝共聚物进行了表征,证明合成了目的产物。利用TEM对PB-g-PS乳胶粒子进行了形态观察,接枝物为球形粒子,且具有核壳结构。 相似文献