硅橡胶/聚苯乙烯/石墨烯复合材料的制备及力学性能

以过氧化苯甲酰(BPO)为引发剂,使苯乙烯(St)在α,ω-羟基聚二甲基硅氧烷(PDMS)和石墨烯纳米片(GN)共存的体系中进行自由基聚合,制备PDMS/聚苯乙烯(PS)/GN共混物;进一步对该共混物进行室温硫化(RTV)获得硅橡胶/PS/GN复合材料。探讨了PDMS与St的进料比、GN用量等对硅橡胶/PS/GN复合材料力学性能的影响。结果表明,当PDMS/St(质量百分比)为70/30、GN/PDMS(质量比)为0.5时,所得硅橡胶/PS/GN复合材料的拉伸强度可达到3.52 MPa,PS和GN对RTV硅橡胶的协同增强效果明显。     

聚甲基丙烯酸甲酯增强聚硅氧烷弹性体的制备及其力学性能

以过氧化苯甲酰(BPO)为引发剂,使甲基丙烯酸甲酯(MMA)在聚二甲基硅氧烷(PDMS)中发生自由基聚合,制备了PDMS/聚甲基丙烯酸甲酯(PMMA)共混物,对共混物进行室温硫化得到PMMA增强聚硅氧烷弹性体,考察了原料配比、BPO用量和聚合时间对弹性体力学性能的影响,并用扫描电子显微镜(SEM)对弹性体的相态结构进行了分析.结果表明,采用室温硫化硅橡胶的方法制备PDMS/PMMA共混物的弹性体,PMMA组分有明显的增强效果;当PDMS/MMA(质量比)为70/30、BPO质量分数为PDMS的1.5%、聚合时间为5 h时,弹性体的拉伸强度可达到4.1 MPa;弹性体具有微观相分离结构,PMMA作为分散相分布于PDMS连续相中.     

聚苯乙烯增强室温硫化硅橡胶的制备及表征

以过氧化苯甲酰为引发剂,使苯乙烯在α,ω-羟基聚(二甲基-甲基乙烯基)硅氧烷(PDM-MVS)中进行自由基聚合,制备了PDM-MVS/聚苯乙烯(PS)共混物。将该共混物在室温下进行硫化,获得了PS增强的室温硫化硅橡胶,并对硅橡胶的力学性能和微观形态进行了表征。结果表明,目标硅橡胶的拉伸强度和扯断伸长率均随PDM-MVS中乙烯基质量分数的增加而增大,当乙烯基质量分数为1.50%时,其拉伸强度达3.9 MPa,扯断伸长率达416%,PS的增强效果明显;目标硅橡胶具有微相分离结构,PS作为分散相均匀分布于PDM-MVS连续相中,两相的相容性随着PDM-MVS中乙烯基质量分数的增加而增强。     

聚甲基丙烯酸甲酯增强聚硅氧烷弹性体

泰山医学院的董建等人以过氧化苯甲酰（BPO）为引发剂，使甲基丙烯酸甲酯（MMA）在聚二甲基硅氧烷（PDMS）中发生自由基聚合，制得PDMS／聚甲基丙烯酸甲酯（PMMA）共混物，室温硫化后得到PMMA增强弹性体。当mPDMS／mMMA为70：30、BPO质量分数为PDMS的1．5％、聚合时间为5h时，弹性体的拉伸强度为4．1MPa，该弹性体具有微观相分离结构，PMMA作为分散相分布于PDMS连续相中。     

聚硅氧烷交联剂与掺杂SiO2协同增强RTV硅橡胶的研究

研究了新型聚硅氧烷交联剂(PCA)与沉淀法SiO2协同增强室温硫化硅橡胶及其增强机理.发现PCA的引入可有效降低PCA/SiO2/PDMS硅橡胶的黏度,提高硫化胶的拉伸强度,保持良好的扯断伸长率,体系中原位生成的SiO2粒子和掺杂的SiO2粒子与PDMS聚合物之间有强烈的相互作用,协同补强效果好.     

硅橡胶/石墨烯复合材料的制备及力学性能

采用高温热解氧化石墨的方式制备石墨烯。通过溶液共混并辅以高速剪切的方式将石墨烯分散到α,ω-羟基聚二甲基硅氧烷(PDMS)中,进而采用室温硫化的方式制备硅橡胶/石墨烯复合材料,并对其力学性能进行表征。结果表明,石墨烯对室温硫化(RTV)硅橡胶的增强效果显著。当石墨烯的含量为1.0%时,硅橡胶/石墨烯复合材料的拉伸强度可达5.13 MPa,是纯RTV硅橡胶拉伸强度的4.8倍。     

石墨烯复合室温硫化硅橡胶的研究

研究了不同方法制备石墨烯和以六甲基二硅氮烷改性石墨烯对室温硫化硅橡胶力学性能的影响,并通过热空气老化试验和热失重分析(TGA)2种方法对改性石墨烯制备的室温硫化硅橡胶的耐高温性能进行了研究。结果表明,使用物理法制备的石墨烯复合室温硫化硅橡胶具有较好的导电性能,而氧化还原法制备石墨烯复合硅橡胶具有较高的力学性能。氧化还原法石墨烯表面经过六甲基二硅氮烷改性后,制备的室温硫化硅橡胶的力学性能得到提高,当加入量为1质量份时,就对室温硫化硅橡胶产生了良好的补强效果,并能大幅度提高室温硫化硅橡胶的抗热氧老化性能和热分解温度。     

水悬浮自搅拌体系中聚丙烯接枝双单体丙烯酸和苯乙烯

以水为分散介质,二甲苯、甲苯为界面剂,过氧化苯甲酰(BPO)为引发剂,在水悬浮自搅拌体系中制备双单体丙烯酸(AA)和苯乙烯(St)接枝聚丙烯共聚物(PP-g-AA/St).重点研究了加料方式、界面剂、分散介质、引发剂、溶胀时间、反应时间、水相阻聚剂、单体组成对接枝反应的影响.得出较佳的工艺条件:反应物料一次加入,投料质量比为二甲苯/水/聚丙烯/单体/过氧化苯甲酰/二氯化锡=2.6/15/10/2/0.015/0.005%,室温溶胀4 h,102℃反应6 h,此条件下双单体接枝率达11.95%,接枝效率高达59.75%.AA与St在物质的量之比为0.846处进行接枝反应时无序共聚副反应严重,傅立叶红外光谱分析结果表明,AA和St接枝到PP大分子链上.     

氢氧化镁在苯乙烯悬浮聚合中的应用研究

利用NaOH和MgCl_2反应制备悬浮聚合分散剂氢氧化镁,以过氧化二苯甲酰(BPO)为引发剂,进行苯乙烯(St)悬浮聚合。研究了分散剂用量、引发剂用量、水和单体比、搅拌速度、反应温度及反应时间对聚苯乙烯(PS)珠粒大小、均匀程度和产率的影响。结果表明:氢氧化镁作为分散剂有很好的稳定作用,当苯乙烯为12 mL,适宜的反应温度为95℃;MgCl_2(1 mol/L)4 mL,NaOH (1 mol/L)8 mL;BPO 0.35g;V(水)∶V(St)=4.0∶1;搅拌速度300 r/min,反应时间80 min,制得的PS珠粒透明度良好,颗粒大小均匀,粒径在1～2 mm,收率可以达到90%。     

室温硫化聚苯乙烯接枝改性硅橡胶的性能研究

采用差示扫描量热分析(DSC)、动态热机械分析(DMTA)和热空气老化的方法,对室温硫化聚苯乙烯接枝改性硅橡胶(PS-PDMS)和硅橡胶(PDMS)的力学性能及耐高低温性能进行了对比研究。结果表明,接枝聚苯乙烯改性硅橡胶的力学性能显著提高,未补强硫化胶的拉伸强度达2.3MPa,白炭黑补强硫化胶的拉伸强度可达4.8MPa;PS-PDMS的结晶熔融峰和阻尼峰值低于PDMS,分别为5℃和8℃,耐低温性能优于PDMS,而耐高温性能远低于PDMS。     

耐油室温硫化硅橡胶的制备与性能研究

制备耐油室温硫化(RTV)硅橡胶,并对其性能进行研究。耐油RTV硅橡胶优化制备条件为:端乙烯基硅油(粘度为1.5Pa·s)/支链型乙烯基硅油(粘度为4.8Pa·s)用量比100/20,含氢硅油(氢质量分数为0.01)/乙烯基摩尔比2,白炭黑/云母用量比15/15。采用该条件制备的RTV硅橡胶物理性能和耐油性能良好。     

Preparation,morphology, and mechanical properties of elastomers based on α,ω‐dihydroxy‐polydimethylsiloxane/polystyrene blends

α,ω‐Dihydroxy‐polydimethylsiloxane/polystyrene (PDMS/PS) blends were prepared by the solution polymerization of styrene (St) in the presence of α,ω ‐dihydroxy‐polydimethylsiloxane (PDMS), using toluene as solvent and benzoyl peroxide (BPO) as initiator. The PDMS/PS blends obtained by this method are a series of stable, white gums, which were vulcanized to elastomers at room temperature with methyl‐triethoxysilicane (MTES). The use level of MTES was far more than the necessary amount used to end‐link hydroxy‐terminated chains of PDMS, with the excess being hydrolyzed to crosslinked networks, which were similar to SiO₂ and acted as filler. Investigations were carried out on the elastomeric materials by extraction measurement, swelling measurement, and scanning electron microscopy. The extraction data show that at each composition the amount of soluble fraction is less than expected and the difference between experimental and theoretical values becomes more and more significant as PS content increases. This is mainly due to the grafting of PS onto PDMS and the entanglement of PS in the interpenetrating polymer network (IPN), which consists of either directly linked PDMS chains or chains linked via PS grafts and is formed by free radical crosslinking of PDMS during the radical polymerization of St. PS grafted on PDMS is insoluble and PS entangled in the IPN is difficult to extract. Both render the soluble fraction to be less than expected. As the St content in preparing PDMS/PS blends increases, the probability of grafting PS onto PDMS also increases, which may subsequently produce a higher crosslinking level of PDMS networks that linked via PS grafts by radical crosslinking. As a result, not only the amount of insoluble PS increases but also PS entangled in the IPN is more difficult to extract. Scanning electron microscopy demonstrates that the elastomer system has a microphase‐separated structure and a certain amount of PS remains in the PDMS networks after extraction, which is in accordance with the extraction data. Moreover, the mechanical properties of the elastormeric materials have been studied in detail. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3542–3548, 2004     

氧化铈对双组分室温硫化硅橡胶耐热性能的影响

以二月桂酸二丁基锡为促进剂、正硅酸乙酯为硫化剂、白炭黑和氧化铈为填料制备双组分室温硫化硅橡胶,研究了氧化铈用量对双组分室温硫化硅橡胶耐热性能的影响。结果表明,氧化铈能明显提高双组分室温硫化硅橡胶的耐热性能,且其用量为8份(质量,下同)时耐热效果较好。在250℃下经72 h热空气老化后,添加了8份氧化铈的双组分室温硫化硅橡胶拉伸强度和扯断伸长率的损失率都最小。添加6份氧化铈的双组分室温硫化硅橡胶的热分解温度较未添加者提高了25.5℃,氧化铈在400～510℃时抑制了硅橡胶的热失重行为。     

导热室温硫化硅橡胶的研究进展

介绍了导热室温硫化硅橡胶的导热机理及导热模型,分析了室温硫化硅橡胶的导热性能及综合性能,并概述了国内外导热室温硫化硅橡胶的研究现状。指出通过填充不同粒径分布的填料或对填料进行适当的表面处理,可以制备高导热室温硫化硅橡胶。     

白炭黑原位填充的改性室温硫化硅橡胶胶黏剂

采用原位填充白炭黑与甲基丙烯酸(酯)改性相结合的方法制备了室温硫化(RTV)硅橡胶胶黏剂,用红外光谱与凝胶渗透色谱表征了RTV硅橡胶的结构及其胶黏剂的相对分子质量,用扫描电子显微镜分析了白炭黑的分散性,并考察了胶黏剂对金属铝黏接性能的影响因素。结果表明,RTV硅橡胶、甲基丙烯酸(酯)与白炭黑形成了共聚物;随着白炭黑含量的增加,胶黏剂的相对分子质量分布变宽;当偶联剂γ-氨丙基三乙氧基硅烷/正钛酸四丁酯(质量比3)质量分数为1.5%,白炭黑质量分数为1.5%,交联剂原硅酸四乙酯及催化剂二月桂酸二丁基锡的质量分数分别为1.0%,0.1%时,胶黏剂粘接铝的最大剪切强度可达到5.64MPa。     

纳米碳酸钙含量对室温硫化硅橡胶热稳定性的影响

测试了不同纳米碳酸钙含量的室温硫化硅橡胶的热稳定性,并结合对不同纳米碳酸钙含量填充硫化胶的热降解活化能的计算可知,随着纳米碳酸钙含量的增加热降解活化能增加,说明纳米碳酸钙的填充可提高室温硫化硅橡胶耐热性能。其机理是纳米碳酸钙与硅橡胶的相互作用,从而提高了纳米碳酸钙填充室温硫化硅橡胶的耐热性能。     

室温硫化硅橡胶的增强改性研究进展

概述了室温硫化硅橡胶的类型、硫化机理、性能及其在宇航领域的应用,综述了室温硫化硅橡胶的增强及改性研究进展,并提出了今后室温硫化硅橡胶的主要研究方向。     

Effect of Carbon Nanotubes on the Structure,Internal Loss Storage,and Damping–Absorption Properties of CNT/PZT/RTV

Composites with damping–absorption performance and storage-loss behavior based on carbon nanotubes as a modifier and zinc titanate/room temperature vulcanized silicone rubbers as a matrix were fabricated by a reactive solution mixing process, wet ball milling, and the three-roller milling method. The microstructures, chemical structures, and morphologies of the composites were characterized by scanning electron microscopy, infrared spectroscopy, and X-ray diffraction. The thermal stabilities were investigated by thermogravimetric analysis. The effect of carbon nanotubes on the comprehensive performance of the carbon nanotube/zinc titanate/room temperature vulcanized silicon rubber composites was investigated. It was found that doping with carbon nanotubes can improve the comprehensive performance of the zinc titanate/room temperature vulcanized silicon rubber complex matrix. The best comprehensive properties were d₃₃?=?72 pC/N, storage modulus?=?4,100?MPa, loss modulus?=?400?MPa, damping coefficient?=?0.23, and absorption coefficients?=?0.4–0.6 for 4?wt% carbon nanotube/zinc titanate/room temperature vulcanized silicon rubber. In addition, the lattice parameters of zinc titanate were found to be highly dependent on the carbon nanotube content, and the absorption and damping performance of the composites were dependent on the frequency and temperature.     

多苯基聚硅氧烷对硅橡胶阻尼性能的影响

以低苯基硅橡胶为基胶,通过添加多苯基聚硅氧烷,制备出阻尼硅橡胶,并对其性能进行了研究。结果表明,加入铂催化的多苯基聚硅氧烷能显著提高硅橡胶在-50-150℃温度区域内的阻尼系数;多苯基聚硅氧烷中侧基数量越多,阻尼系数峰值出现的温度越高。加入铂催化的多苯基聚硅氧烷能够显著提高硅橡胶的撕裂强度和断裂伸长率,对硅橡胶的拉伸强度和热稳定性影响不大。两种催化体系合成的多苯基聚硅氧烷对硅橡胶阻尼系数的影响不同,Ph3SiO-接枝率较低时,加入锡催化剂多苯基聚硅氧烷的硅橡胶的阻尼峰值较高;接枝率进一步增加时,加入铂催化多苯基聚硅氧烷的硅橡胶的阻尼系数曲线出现尖峰,而加入锡催化剂多苯基聚硅氧烷的硅橡胶的阻尼峰仍呈现宽峰。