不同硫化体系天然胶乳胶膜的热氧降解过程及差异

用热重法微商热重法（ Ｔ Ｇ Ｄ Ｔ Ｇ） 和差热分析（ Ｄ Ｔ Ａ） 研究了不同硫化体系天然胶乳胶膜的热氧降解过程。试验结果表明,胶乳胶膜的降解反应均分三步进行,但降解过程存在较大差异,过氧化物预硫化胶乳胶膜的热氧降解最为彻底,而硫黄／ 促进剂 Ｔ Ｍ Ｔ Ｄ／ 氧化锌体系硫化胶乳胶膜的热氧稳定性最好。     

一种新型水基粘合剂

据《塑料与橡胶新闻》报道，俄、美科学家研究结果表明，低分子量的聚丁二烯（ＰＢＤ）与顺式丁二烯酸酐（ＭＡ）接枝形成的化合物是一种十分优良的水基粘合剂。在非极性聚丁二烯主链上接枝高极性和高活性的酐基团，使ＰＢＤＭＡ具有极强的粘合性能。这种化合物既可分散于水中制成胶乳，又可制成水溶液。用作粘合剂的ＰＢＤＭＡ胶乳，其ｐＨ值应保持４．５～５，接枝ＭＡ基团的浓度最低为５％，最高可达２０％。用作粘合剂的ＰＢＤＭＡ溶液，其ＭＡ浓度不得低于１０％、最佳ｐＨ值为６．５～８。ＰＢＤＭＡ粘合剂适用于丁苯胶、顺丁胶、天然…     

降解天然橡胶胶乳的接枝共聚研究

研究了不同降解程度的天然橡胶胶乳与丙烯酸丁酯 ( BA)的接枝反应及反应条件对接枝率的影响。发现随着降解时间增加 ,降解橡胶的粘均相对分子质量降低不是直线下降 ,而是有一个明显的突跃 ,降解胶乳共聚反应活性并未降低 ,且共聚物中 BA聚合链段与橡胶链段的相对比例 (质量比 )明显增加     

硬段含量对聚酯型聚氨酯弹性体形态与性能的影响

采用本法合成了一系列不同硬段含量的聚（１，４－丁二醇己二酸）酯型聚氨酯（简称ＰＢＡ型ＰＵ）弹性体，并用ＤＳＣ，ＷＡＸＤ，ＴＥＭ，ＳＥＭ，ＳＡＸＳ测试手段对其微相分离程度和结晶形态进行了表征，测定了材料的拉伸性能，讨论了硬段含量对材料形态与性能的影响。结果表明：ＰＢＡ型ＰＵ弹性体中微相分离程度以及软，硬链段的结晶性随硬段含量的提高而变化。拉伸性能受其内部微相分离程度和链段结晶性的相互影响。     

甲基丙烯酸甲酯与降解天然橡胶胶乳共聚的研究

研究了不同降解程度的天然橡胶胶乳与甲基丙烯酸甲酯 (MMA)共聚反应 ,发现随着降解时间增长 ,共聚物中 MMA聚合链与橡胶段的相对比例 (重量比 )明显增加。找到了一种适用于降解胶乳与 MMA共聚混合物的分离方法     

交联聚乙酸乙烯脂胶乳的合成

分别以二乙烯基苯、双甲基丙烯酸乙二醇酯和甲基丙烯酸烯丙基酯（ＡＭＡ）为交联剂，十二烷基硫酸钠（ＳＬＳ）为乳化剂，过硫酸铵为引发剂，合成了交联聚乙酸乙烯酯（ＰＶＡｃ）胶乳。结果表明，ＡＭＡ是乙酸乙烯酯乳液聚合最理想的交联剂，其用量为单体量的２％时，交联度可达到８５％以上。所用ＳＬＳ的浓度为１１．６ｍｍｏｌ／Ｌ时，合成了交联度为８７．４％、粒径为８４．５ｎｍ的交联ＰＶＡｃ胶乳。     

交联聚乙酸乙烯酯胶乳的合成

分别以二乙烯基苯、双甲基丙烯酸乙二醇酯和甲基丙烯酸烯丙基酯（ＡＭＡ）为交联剂，十二烷基硫酸钠（ＳＬＳ）为乳化剂，过硫酸铵为引发剂，合成了交联聚乙酸乙烯酯（ＰＶＡｃ）胶乳。结果表明，ＡＭＡ是乙酸乙烯酯乳液聚合最理想的交联剂，其用量为单体量的２％时，交联度可达到８５％以上。所用ＳＬＳ的浓度为１１．６ｍｍｏｌ／Ｌ时，合成了交联度为８７．４％、粒径为８４．５ｎｍ的交联ＰＶＡｃ胶乳。     

SBS和反应性单体本体接枝共聚合机理

以过氧化苯甲酰（ＢＰＯ）为引发剂，ＳＢＳ分别与甲基丙烯酸甲酯（ＭＭＡ）、甲基丙烯酸丁酯（ＢＭＡ）及乙酸乙烯酯（ＶＡＣ）进行本体接枝共聚合。根据均聚物的生成量和聚合物的相态结构，认为ＳＢＳ防与ＭＭＡ（或ＢＭＡ）的反应机理与系山、伊田等的研究结果一致；ＳＢＳ与ＶＡｃ的反应机理是，ＢＰＯ·与ＶＡｃ生成ＰＶＡｃ链自由基，继而向ＳＢＳ主链转移。     

PE—MAH的合成及其对PE／NBR的增容作用

聚乙烯（ＰＥ），马来酸酐（ＭＡＨ）和过氧化二异丙苯（ＤＣＰ）在溶液中反应，其产物经多次纯和红外光谱分析证明，ＭＡＨ以化学链连接到ＰＥ分子链上，接枝率达０．５ＭＡＨ／１００Ｅ，即相当平均每个ＰＥ上接枝有１０个ＭＡＨ。用不同接枝率的聚乙烯接枝马来酸酐聚物（ＰＥ－ＭＡＨ）作为极性差别较大的ＰＥ和丁腈橡胶（ＮＢＲ）的相容剂，分别研究其接枝率和用量对共混物的拉伸强度和低温冲击强度的影响，结果发现：ＰＥ－ＭＡ     

不同硫化体系天然胶乳胶膜的热氧降解过程及差异

用热重法，微商法重法和差热分析研究了不同硫化体系天胶乳胶膜的热氧降解过程。试验结果表明，胶乳胶膜的降解反应均分三步进行，但降解过程存在较大差异，过氧化物预硫化胶乳胶膜的热氧降解最为彻底，而硫黄／促进剂ＴＭＴＤ＝氧化锌体系硫化胶乳胶膜的热氧稳定性最好。     

丙烯酸甲酯与降解天然橡胶胶乳的共聚研究

研究了不同降解程度的天然橡胶胶乳与丙烯酸甲酯(MA)的共聚反应及反应条件对接枝率的影响。发现 随着降解时间增加,共聚反应活性并未降低。并确定降解天然橡胶胶乳与丙烯酸甲酯共聚的较佳反应条件。     

不同改性方法对天然胶乳的性能影响

分别采用氯化石蜡与Sb2O3共混改性天然胶乳、用三氯溴甲烷卤化加成改性天然胶乳、以3-溴丙烯接枝共聚改性天然胶乳,对3种不同工艺所制备的改性天然胶乳与未改性天然胶乳进行了胶体性能、阻燃性及耐溶剂性能的比较。研究结果表明：3种改性胶乳的粘度比未改性天然胶乳的要高,且接枝改性胶乳和卤化改性胶乳变化较大,共混改性胶乳的变化较少;3种改性胶乳的阻燃性能高于未改性天然胶乳的;卤化改性天然胶乳和接枝改性天然胶乳的耐溶剂性较好,而共混改性天然胶的耐溶剂性较差。     

Polymer electrolyte membrane with nanomatrix channel prepared by sulfonation of natural rubber grafted with polystyrene

High‐proton‐conductive polymer electrolyte with a nanomatrix channel was prepared by graft copolymerization of styrene onto deproteinized natural rubber followed by sulfonation with chlorosulfonic acid. First, natural rubber latex was purified with urea in the presence of surfactant to remove almost all proteins present in the rubber. Second, graft copolymerization of styrene onto deproteinized natural rubber was carried out with tert‐butyl hydroperoxide/tetraethylenepentamine as an initiator at 30°C in latex stage. The graft‐copolymerized natural rubber (DPNR‐graft‐PS) was sulfonated with chlorosulfonic acid in chloroform solution at an ambient temperature. The resulting sulfonated DPNR‐graft‐PS was characterized by FTIR spectroscopy, solid state ¹³C CP/MAS NMR spectroscopy, elemental analysis, and transmission electron microscopy. High proton conductivity of about 0.1 S/cm, less water uptake of 24 wt % and comparatively good stress at break of 9 MPa were accomplished at suitable contents of styrene units and sulfur, i.e., 32 wt % and 75 mol %, respectively. The high proton conductivity, excellent stability, and good mechanical properties were associated with not only the formation of the nanomatrix channel but also a specific concentration of sulfuric acid group. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Preparation and graft‐copolymerization of hydrogenated natural rubber in latex stage

Preparation and graft‐copolymerization of hydrogenated natural rubber are performed in latex stage after removal of proteins from the rubber with urea and surfactant. Hydrogenation of deproteinized natural rubber (DPNR) latex is carried out with palladium catalyst under hydrogen atmosphere. The hydrogenated DPNR (HDPNR) is crosslinked with a peroxide followed by graft‐copolymerization of styrene (Sty) and acrylonitrile (AN) in latex stage in order to prepare a graft‐copolymer of crosslinked HDPNR with poly(Sty‐co‐AN) (HDPNR‐graft‐PSAN). Characterization of the products is performed by nuclear magnetic resonance spectroscopy. The conversion of hydrogenation is investigated with respect to the catalyst feed, acidity (pH), and dry rubber content. In the resulting HDPNR‐graft‐PSAN, mole fraction of AN and Sty is 1.4 and 5.8 mol %, respectively. The graft‐copolymer is used to improve properties of PSAN as an impact modifier. The Charpy impact strength of crosslinked HDPNR‐graft‐PSAN/PSAN is about eight times as high as that of PSAN. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42435.     

Studies on the curing behaviour and mechanical properties of styrene/methyl methacrylate grafted deproteinized natural rubber latex

The graft copolymerization of styrene/methyl methacrylate (MMA) onto deproteinized natural rubber (DPNR) latex was carried out using ammonium peroxy disulfate (N₂H₈O₈S₂) as the initiator. The presence of the grafted polystyrene (PS) and polymethyl methacrylate (PMMA) on the rubber backbone was confirmed by FTIR spectroscopy. The effects of monomer concentrations on curing characteristics and mechanical properties were studied. It was found that the cure time and scorch time were increased with increasing monomer concentration whereas the torque_max–min value was slightly decreased. It was also noted that the increase in the monomer concentration resulted in stiffer rubber with increased modulus and reduced elongation at break.     

硫化型吸水膨胀天然橡胶的制备研究

采用原位聚合法在天然胶乳中制备出吸水膨胀天然橡胶,并硫化制得硫化型吸水橡胶（WSNR）。傅立叶红外谱图分析发现该原位聚合法能使聚丙烯酸钠接枝到天然橡胶的分子链上;TG和DTG分析表明接枝了聚丙烯酸钠的天然橡胶的热稳定性能有一定的提高;不同硫化体系对吸水橡胶的硫化性能影响考查结果表明：随着硫黄用量的增加,WSNR的吸水性能降低、力学性能得到提高。     

苯乙烯、丙烯腈与降解天然胶乳的共聚研究

以BPO-FeSO4为氧化还原引发体系，采用种子乳液聚合技术，在降解天然胶乳DNR粒子上接枝共聚苯乙烯(St)和丙烯腈(AN)，用正交实验法研究了较佳反应条件，考察反应温度、反应时间及投料比对单体转化率、接枝率和接枝效率的影响，并用红外光谱对共聚物进行表征。     

Studies on the Cell Structure and Mechanical Properties of NR/Latex Reclaim/HSR Based Micrqcellular Sheets

In natural rubber/high styrene resin microcellular sheets, part of natural rubber was replaced by latex reclaim prepared from waste latex products. The mechanical properties and cell structure of the products were evaluated. It was found that latex reclaim can replace about 30% of natural rubber without affecting the technical properties of the microcellular sheets.