加成型液体乙烯基硅橡胶的研制Ⅰ.乙烯基硅油等对物理机械性能的影响

考察了乙烯基硅油及含氢硅油对加成型液体乙烯基硅橡胶物理机械性能的影响。结果表明，在100份乙烯基硅橡胶中加入10份乙烯基质量分数为10％的硅油，4.6份含氢硅油，用20份经表面处理的白炭黑增强，可得到拉伸强度为3.8MPa，撕裂强度为7.6kN/m，扯断伸长率为162％的乙烯基硅橡胶。     

Beneficial role of “sol–gel” synthesized mesoscale silica networks on the performance of liquid silicone elastomer

This piece of contribution highlights the profound effect of unique mesoscale morphology of tailor made nanosilica assembly (SS‐Silica), synthesized by sol–gel route, on the mechanical and dynamic rheological properties of platinum catalyzed addition‐cured silicone elastomers. While commercial colloidal nanosilica (CS Silica) is used as the control nanofiller representing particulate morphology, the tailor‐made SS‐Silica having highly percolated network structure offers 10‐fold increase in storage modulus of the uncured reactive PDMS precursor nanocomposite with stable dynamic rheological behavior and more than 180% enhancement in tensile strength of resulting liquid silicone rubber (LSR) produced on curing, as compared to colloidal silica of commercial origin. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40125.     

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。     

硅橡胶-石墨烯层结构绝缘电磁屏蔽材料的研发

以甲基乙烯基硅橡胶生胶为基胶,添加含氢硅油、铂金催化剂等,采用压延工艺制得1~3 mm厚硅橡胶片材;以硅烷偶联剂改性石墨烯并与胶粘剂混合制得涂料,喷涂在硅橡胶片材表面,制得硅橡胶-石墨烯层结构绝缘电磁屏蔽材料。该材料初始电磁屏蔽效能可达82 d Bm,拉伸强度6.5 MPa,电气强度25.3 k V/mm,经紫外光及热老化后,电磁屏蔽效能、力学性能及绝缘性能虽有不同幅度的下降,但仍能满足10 k V带电作业机器人外绝缘及电磁屏蔽应用需求。     

Improvement of thermo-electrical properties of polymer composites filled with multiwall carbon nanotubes decorated carbon fillers

To enhance the thermo-electrical properties of liquid silicone rubber (LSR) in applications, the carbon fibres (CFs) modified by multiwall carbon nanotubes (MWCNT) on the surfaces were used as the fillers. The MWCNT-modified CFs (MPCFs) were analysed by Fourier transform infrared spectra, thermogravimetric analysis, scanning electron micrograph and energy dispersive X-ray spectroscopy. It was found that MWCNT were successfully adsorbed onto the surface of CFs. The MPCFs functioned as conductive fillers in LSR for thermal and electrical conductivity application and exhibited significant enhancement. The effects of MPCFs loading on thermal conductivity and volume resistivity of LSR composites were investigated in detail. Results of this work revealed that the MPCFs/LSR composites possessed a thermal conductivity of 0.73?W?m^?1?K^?1 with 14?vol.-% filler loading, approximately 3.48-fold higher than that of pure LSR substrate. And with the increase of MPCFs loading, the least volume resistivity of MPCFs/LSR composites is 10?Ω?cm. Besides, compared with that of neat LSR, the tensile strength of MPCFs/LSR composites increased 0.913?MPa.     

纳米SiO2对有机硅树脂增强加成型硅橡胶性能的影响

以由单官能硅氧单元和四官能硅氧单元组成的有机硅树脂(简称MQ硅树脂)增强加成型硅橡胶为基体,采用机械共混方式加入少量纳米S iO2,研究了纳米S iO2对MQ硅树脂增强硅橡胶的性能影响。结果表明,纳米S iO2在硅橡胶中以聚集体的形式存在,大小约为几十到几百纳米;纳米S iO2填充MQ硅树脂增强的硅橡胶的邵尔A硬度、拉伸强度和扯断伸长率与未填充纳米S iO2的硅橡胶基本相当,撕裂强度增大;其高温热稳定性优于未填充纳米S iO2的硅橡胶,但其透明性稍有下降。     

HOMMT/MVQ纳米复合材料的制备与性能研究

采用超支化技术对有机蒙脱土(OMMT)进行改性制备超支化有机蒙脱土(HOMMT),并制备HOMMT/甲基乙烯基硅橡胶(MVQ)纳米复合材料,对其性能进行研究。结果表明,HOMMT呈剥离纳米片层结构,与OMMT相比,HOMMT耐热性能提高;随着HOMMT用量的增大,HOMMT/MVQ复合材料拉伸强度减小;与MVQ硫化胶相比,当HOMMT用量为1份时,HOMMT/MVQ纳米复合材料拉伸强度提高了28%,拉断伸长率提高了67%,起始降解温度升高了25℃。     

模拟宫腔液对加成型液体硅橡胶性能的影响

采用模拟宫腔液对加成型液体硅橡胶硫化胶进行浸泡处理,通过全反射傅里叶红外光谱分析、表面接触角和热重分析对模拟宫腔液浸泡前后的硫化胶进行表征,研究模拟宫腔液的浓度和浸泡时间对硫化胶性能的影响。结果表明,随着浸泡时间的延长和模拟宫腔液浓度的增大,硫化胶的拉伸强度、断裂伸长率和撕裂强度有所下降,硬度基本不变;但即使经过3倍标准浓度模拟宫腔液90℃下浸泡12天后,硫化胶的拉伸强度、断裂伸长率、撕裂强度的降低幅度均低于10％,而且硫化胶的化学性质稳定,亲水性提高,热稳定性良好。因此,加成型液体硅橡胶是制作宫内节育器的理想材料。     

Characterization and properties of activated nanosilica/polypropylene composites with coupling agents

In this work, nanosilica/polypropylene composites containing 1 wt% of silica nanoparticles were prepared by melt mixing in a Thermo Haake internal mixer. Prior compounding, nanosilica was subjected to surface activation using sodium hydroxide (NaOH) solution. The effectiveness of the activation process was evaluated by measuring the amount of hydroxyl groups ( OH) on the surface of nanosilica via titration method and supported by FTIR analysis. Two coupling agents namely 3‐aminopropyl triethoxysilane (APTES) and neopentyl (diallyl)oxy, tri(dioctyl) phosphate titanate (Lica 12) were used for surface treatment after activation process. The mechanical properties of polypropylene matrix reinforced with silica nanoparticles were determined by tensile and impact test. Hydroxyl groups on the nanosilica surface played an important role in enhancing the treatment with silane coupling agents. To increase the amount of hydroxyl groups on the nanosilica surface, the optimum concentration of NaOH is 1 mol%. Tensile strength, tensile modulus, and impact strength of nanosilica/PP composites improved with activation process. As the coupling agent is concerned, APTES coupling agent is more pronounced in enhancing the mechanical properties of the composites when compared with Lica 12 coupling agent. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Silicone rubbers for dielectric elastomers with improved dielectric and mechanical properties as a result of substituting silica with titanium dioxide

One prominent method of modifying the properties of dielectric elastomers (DEs) is by adding suitable metal oxide fillers. However, almost all commercially available silicone elastomers are already heavily filled with silica to reinforce the otherwise rather weak silicone network and the resulting metal oxide filled elastomer may contain too much filler. We therefore explore the replacement of silica with titanium dioxide to ensure a relatively low concentration of filler. Liquid silicone rubber (LSR) has relatively low viscosity, which is favorable for loading inorganic fillers. In the present study, four commercial LSRs with varying loadings of silica and one benchmark room-temperature vulcanizable rubber (RTV) were investigated. The resulting elastomers were evaluated with respect to their dielectric permittivity, tear and tensile strengths, electrical breakdown, thermal stability and dynamic viscosity. Filled silicone elastomers with high loadings of nano-sized titanium dioxide (TiO₂) particles were also studied. The best overall performing formulation had 35 wt.% TiO₂ nanoparticles in the POWERSIL® XLR LSR, where the excellent ensemble of relative dielectric permittivity of 4.9 at 0.1 Hz, breakdown strength of 160 V µm^?1, tear strength of 5.3 MPa, elongation at break of 190%, a Young’s modulus of 0.85 MPa and a 10% strain response (simple tension) in a 50 V μm^?1 electric field was obtained.     

高强度硅橡胶混炼胶的制备

用用Ｚ浆捏合机，将端乙烯基硅橡胶，气相白炭黑及羟基硅氧烷进行混炼，制备了高强度硅橡胶混炼胶。在白炭黑用量为４０份时，混炼胶硫化胶的拉伸强度为１１．７ＭＰａ，撕裂强度为４９．７ｋＮ／ｍ。９份端乙烯基硅橡胶与１份普通甲基乙烯基硅橡胶并用制备的混炼胶，其撕裂强度高达５７．７ｋＮ／ｍ，实验所制得的混炼胶与国外同类产品物理机械性能相当。     

硅橡胶/有机改性蒙脱土纳米复合材料的性能研究

用熔体插层法制备甲基乙烯基硅橡胶(MVQ)/有机改性蒙脱土(OMMT)纳米复合材料并研究其微观结构和性能。结果表明:OMMT改性剂疏水性从优到劣的顺序为I.44P,I.30P,Bengel434,I.44P和I.30P在MVQ中的分散性优于Bengel434;MVQ/OMMT纳米复合材料的物理性能和热稳定性从优到劣的顺序为MVQ/I.44P,MVQ/I.30P,MVQ/Bengel434纳米复合材料;添加40份I.44P的MVQ/I.44P纳米复合材料的100%定伸应力、拉伸强度和撕裂强度比纯胶有较大提高。     

有机硅基体与填料表面处理对电子灌封胶性能的影响

文章研究α,ω-二乙烯基聚二甲基硅氧烷（乙烯基硅油）粘度、硅烷偶联剂类型及用量对电子灌封胶性能的影响。结果表明：随着乙烯基硅油粘度的增加,灌封胶的拉伸性能增加;乙烯基三乙氧基硅烷（A-151）处理的氮化铝所制备的灌封胶的导热率和耐热性能突出,并且填料与基体间界面结合情况良好;优化后,A-151的用量为填料量的1 wt%。     

Dispersion,Mechanical and Thermal Properties of Epoxy Resin Composites Filled with the Nanometer Carbon Black

The nanometer carbon black (CB) was employed to prepare epoxy resin/carbon black (EP/CB) composites by blending-casting method. The different modified methods of silicone coupling agent were used to improve the dispersion of CB in epoxy resin. The mechanical and thermal properties of EP/CB composites were investigated. Experimental results showed that the mechanical properties increased at first, but decreased with excessive addition of CB. When the mass fraction of CB was 2%, the mechanical properties were maximum. The use of modified CB significantly enhanced the mechanical properties of the composites. For given CB loading, the CB modified by pretreatment method displayed better dispersion in the epoxy resin than that of the direct mixing method. SEM observation revealed that the tensile fracture surface of the composite filled with 2 wt% modified CB held more microcracks than that of 5 wt% modified CB, and the formed microcracks could consume more energy of rupture, finally to have better tensile strength. DSC analysis showed that the glass transition temperature (Tg) of the composites increased with the increasing mass fraction of CB.     

离子束表面沉积对泡沫硅橡胶性能的影响

采用铜离子束辅助增强沉积技术对泡沫硅橡胶进行表面改性处理，分析由此引起的材料密度、硬度及电阻率的变化，研究了表面沉积导电薄膜对泡沫硅橡胶拉伸性能、压缩应力－应变性能及压缩永久变形的影响。结果表明，采用铜离子束辅助增强沉积技术，在不影响材料力学性能的前提下，可改进泡沫硅橡胶的抗静电性能。     

功能化POSS对硅橡胶力学性能的影响及机理研究

研究了八聚笼型倍半硅氧烷(POSS)功能化侧基的种类和用量对硅橡胶力学性能的影响。结果表明,POSS的加入使硅橡胶的拉伸强度和断裂伸长率均下降,硬度均提高。乙烯基POSS的加入显著延长了硅橡胶的正硫化时间。POSS的加入能显著降低硅橡胶的压缩永久变形,乙烯基POSS的效果比甲基POSS好;且乙烯基含量越高,压缩永久变形越小。分析了功能化POSS对硅橡胶力学性能的影响机理。     

加成型液体硅橡胶用含环氧基的有机硅增粘剂的制备、表征及性能

以烯丙基缩水甘油醚和四甲基环四硅氧烷为原料,制备加成型液体硅橡胶用含环氧基的有机硅增粘剂。用红外光谱和核磁共振氢谱对其结构进行了表征,考察了加入量对硅橡胶胶料黏度及硫化胶硬度、介电常数、介质损耗因数、绝缘电阻率、电气强度、粘接性能及封装二极管高温反向漏电流的影响。结果表明:增粘剂能提高硅橡胶的粘接强度;影响其绝缘电阻率和电气强度;降低封装二极管的高温反向漏电流;基本不影响硅橡胶胶料黏度及硫化橡胶的硬度、介电常数、介质损耗因数。     

甲基乙烯基硅橡胶加成硫化研究

探讨了甲基乙烯基硅橡胶中乙烯基含量、多乙烯基硅油、舍氢硅油和氟铂酸对加成硫化硅橡胶物理机械性能的影响。结果表明．在150份乙烯基质量分数为0．13％的硅橡胶中加入1份硅氢基质量分数为1．65％的舍氢硅油、2份乙烯基质量分数为8％的多乙烯基硅油和4份羟基硅油，用40份白炭黑增强，可得到拉伸强度为8．71MPa，撕裂强度为52．14kN／m的乙烯基硅橡胶。     

Thermal and mechanical properties of liquid silicone rubber composites filled with functionalized graphene oxide

To improve the thermal and mechanical properties of liquid silicone rubber (LSR) for application, the graphene oxide (GO) was proposed to reinforce the LSR. The GO was functionalized with triethoxyvinylsilane (TEVS) by dehydration reaction to improve the dispersion and compatibility in the matrix. The structure of the functionalized graphene oxide (TEVS‐GO) was evaluated by Thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectra, X‐ray diffraction (XRD), and energy dispersive X‐ray spectroscopy (EDX). It was found that the TEVS was successfully grafted on the surface of GO. The TEVS‐GO/LSR composites were prepared via in situ polymerization. The structure of the composites was verified by FTIR, XRD, and scanning electron microscopy (SEM). The thermal properties of the composites were characterized by TGA and thermal conductivity. The results showed that the 10% weight loss temperature (T₁₀) increased 16.0°C with only 0.3 wt % addition of TEVS‐GO and the thermal conductivity possessed a two‐fold increase, compared to the pure LSR. Furthermore, the mechanical properties were studied and results revealed that the TEVS‐GO/LSR composites with 0.3 wt % TEVS‐GO displayed a 2.3‐fold increase in tensile strength, a 2.79‐fold enhancement in tear strength, and a 1.97‐fold reinforcement in shear strength compared with the neat LSR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42582.     

Investigation on Sound Absorption Function and Mechanical Behavior of Polycarbonate/Nanosilica-based Nanocomposites

The present study reports the morphological, mechanical, and sound absorption properties of polycarbonate-based nanocomposites containing nanosilica (0.3 and 0.6?wt%). To this end, the specimens were prepared by melt mixing in a twin-screw extruder. The scanning electron microscopy was also used to ensure the well distribution of nanosilica in the polymeric matrix. The mechanical properties were investigated by tensile, flexural strength, Izod impact, and hardness tests. At the end, sound absorption coefficient of the specimens was checked by standing wave sound impedance tube method in the frequency range of 250–6,300?Hz. The results showed that only a small amount of nanosilica could improve the mechanical properties of specimens. However, the sound absorption function of specimens had a gradual improvement by increasing nanosilica content. Tensile modulus and strength at yield of the nanocomposite specimens were higher than that of the neat polycarbonate. On the contrary, a decrease in elongation at break was reported, which was attributed to the reduced mobility of the polymer chains due to the presence of nanoparticles. The same behavior was observed in the test results of Izod impact strength of nanocomposites so that adding nanosilica with the wt% of 0.6 to the neat polycarbonate, the impact strength improved by only 5.3%. According to the findings, polycarbonate composites with 0.3?wt% nano-silica, in addition to strengthening the mechanical properties (tensile modulus, flexural strength, and stiffness), could improve the acoustic characteristics of the specimens in low and mid frequencies. The findings also revealed that the performance of pure polycarbonate and 6?wt% nanosilica polycarbonate in upper frequency range was higher and approximately the same as that for 3?wt% nanosilica polycarbonate.