Effect of organic modification on structure and properties of room‐temperature vulcanized silicone rubber/montmorillonite nanocomposites

The aim of this work was to study the effect of different organomontmorillonite on the structure and properties of room‐temperature vulcanized silicone rubber (RTV) composites. Quaternary ammonium salts (QAS) and hyperbranched QAS were used as intercalation agents to treat Na⁺‐montmorillonite and formed two kinds of organomontmorillonite, OMMT and HOMMT. OMMT/RTV and HOMMT/RTV composites were prepared using these organomodified silicate layers. Properties such as tensile strength, elongation at break, swelling behavior, and thermal stability were researched and compared. The addition of OMMT and HOMMT improved the mechanical properties of RTV composites. The composites with 3 mass % HOMMT showed the highest tensile strength and elongation at break, 5.4 MPa and 425%, which was 29 and 97% higher than that of pure RTV. The RTV composites exhibited excellent thermal stability and swelling behavior. At loading of 3 mass % of HOMMT, T_onset, and T_max was 452 and 640°C, respectively, 33 and 150°C higher than that of pure RTV. A combination of X‐ray diffraction (XRD) test, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies was used to characterize the structure and reinforcing mechanism of these clays. The diffraction peaks in XRD curves were almost absent in the scattering curve of RTV/HOMMT (3 mass %). This was due to the possibility of having exfoliated silicate layers dispersed in the polymer matrix. A careful observation of an area of platelet tactoid of 3% HOMMT filled composite in SEM and TEM revealed the uniform dispersion of the silicate layers in the composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

甲基乙烯基硅橡胶/有机蒙脱土母炼胶纳米复合材料的制备、结构与性能

采用溶液插层法和母炼胶混炼工艺制备了甲基乙烯基硅橡胶(MVQ)/有机蒙脱土母炼胶(OMMT-MB)纳米复合材料,通过X射线衍射(XRD)、透射电子显微镜(TEM)对复合材料进行了表征,研究了复合材料的拉伸性能与热稳定性能,并与直接共混法制备的MVQ/有机蒙脱土(OMMT)复合材料和MVQ/白炭黑复合材料进行了对比,分析了OMMT的增强机理.结果表明,MVQ/OMMT-MB纳米复合材料中的OMMT完全剥离,且均匀分散在MVQ基体中;当OMMT质量分数为20%时,MVQ/OMMT-MB复合材料的拉伸性能优于MVQ/OMMT复合材料,拉伸强度和扯断伸长率分别增大至1.41 MPa、490%;其与MVQ/白炭黑复合材料相比,两者的拉伸强度相当,扯断伸长率增大了30%;MVQ/OMMT-MB复合材料的热稳定性略优于MVQ/OMMT复合材料,但比MVQ/白炭黑复合材料差.     

熔体插层制备硅橡胶/蒙脱土纳米复合材料的性能研究

通过熔体插层成功制备了硅橡胶／蒙脱土纳米复合材料，通过XRD和SEM分析可知，在所选择的两步工艺务件下。蒙脱土被硅橡胶分子链插层剥离。获得剥离型的纳米复合材料。同时，测试了其力学性能和耐热性能。所得到的复合物的性能较纯硅橡胶有很大的提高，且与气相法白炭黑填充体系的性能相当。并且研究了硅烷偶联剂对填料-硅橡胶之间的增强作用。     

淀粉对蒙脱土/丁腈橡胶纳米复合材料结构和性能的影响

采用蒙脱土水悬浮液/橡胶乳液共混-共凝复合技术制备蒙脱土/丁腈橡胶纳米复合材料时,在蒙脱土水悬浮液和丁腈胶乳的混合体系中加入淀粉,考察了淀粉用量对蒙脱土/丁腈橡胶纳米复合材料结构和性能的影响。结果表明,淀粉的加入有利于蒙脱土片层形成剥离型结构。当蒙脱土用量为5份、淀粉用量为10份时,蒙脱土几乎呈完全剥离状态;随着淀粉用量的增加,该复合材料的邵尔A硬度、100%定伸应力、拉伸强度、扯断伸长率和撕裂强度均有所提高。     

动态硫化乙烯-辛烯共聚物/硅橡胶热塑性弹性体性能的影响因素

采用Haake转矩流变仪制备了乙烯-辛烯共聚物(POE)/硅橡胶(MVQ)动态硫化热塑性弹性体(TPV),考察了共混温度、转速、动态硫化时间对POE/MVQ共混物硫化特性、TPV物理机械性能及加工特性的影响,观察了硫化剂不同投料方式下TPV的外观形貌。结果表明,在共混温度为130℃、转速为50～60 r/min、动态硫化时间约为8 min的条件下,采用POE与MVQ混匀后分3批加入硫化剂的方式,所得POE/MVQ TPV的综合性能较好,表面光滑且有韧性。     

增塑剂对硅橡胶硫化胶性能的影响

在确定硅橡胶基本配方的前提下，分析了增塑荆对硅橡胶硫化胶性能的影响。研究结果表明，试验中选用的酯类增塑剂和醇类增塑荆均能明显降低硅橡胶硫化胶的模量，但采用自制的环氧改性胶粘荆进行硅橡胶硫化胶与金属粘接时，含酯类增塑荆的硫化胶粘接效果较好。试样破坏形式为橡胶内聚破坏；而采用醇类增塑剂的硫化胶。粘接质量较差。试样破坏形式均为粘接面破坏。     

Preparation and characterization of high performance exfoliated montmorillonite/silicone rubber nanocomposites with enhanced mechanical properties

Highly exfoliated and intercalated silicone rubber (SR) nanocomposites based on natural montmorillonite (Cloisite Na⁺) and organically modified montmorillonite (Cloisite 30B and Cloisite 20A) were successfully prepared by melt‐mixing technique. Dispersion of the nanoclays in the rubber nanocomposites was subsequently investigated. As indicated by the X‐ray diffraction (XRD) analysis, intercalation, and exfoliation of the clay particles in the nanocomposites was achieved at less than 8 parts per hundred (phr) rubber by weight, irrespective of the initial interlayer spacing of the nanoclay particles. Both Cloisite Na⁺ and Cloisite 30B were spontaneously transformed into exfoliated microstructures during the vulcanisation stage. Overall, the use of the nanoclays in silicone rubber improved the Young's modulus, tensile strength, and elongation at break by more than 50% as compared with the control rubber. In addition, this work provided a fresh insight into the way intercalated and exfoliated morphologies affect mechanical properties of silicone rubber nanocomposites. It was shown that the exfoliated Cloisite Na⁺ yielded outstanding mechanical properties with low hysteresis at the same loading of the exfoliated Cloisite 30B and intercalated Cloisite 20A organoclays. As expected, the formation of crosslinks affected the mechanical properties of the rubber vulcanizate significantly. POLYM. ENG. SCI., 53:2603–2614, 2013. © 2013 Society of Plastics Engineers     

有机蒙脱土对聚氯乙烯/丁腈橡胶纳米复合材料结构与性能的影响

采用熔融插层法制备了有机蒙脱土(OMMT)/聚氯乙烯(PVC)/丁腈橡胶(NBR)纳米复合材料,研究了复合材料的结构,考察了OMMT填充量对复合材料物理机械性能、耐热性能及耐溶剂性能的影响。结果表明,OMMT在复合材料中实现了纳米级分散,且极性PVC大分子在剪切力和热的作用下插入OMMT层间,形成PVC-OMMT纳米复合材料;随着OMMT填充量的增加,OMMT/PVC/NBR纳米复合材料的拉伸强度、300%定伸应力均先升高后降低,扯断伸长率降低,邵尔A硬度和永久变形呈增大的趋势,回弹性变化不大,耐溶剂性能先提高后降低;OMMT/PVC/NBR复合材料的耐热性能优于未填充OMMT复合材料。     

Preparation,structure, and properties of montmorillonite/cellulose II/natural rubber nanocomposites

In this work, sodium montmorillonite clay was added, as filler, to nanocomposites of natural rubber (NR) and cellulose II (regenerated cellulose) in amounts varying from 0 to 5 phr (per hundred resin). Natural rubber (NR)/cellulose II/montmorillonite nanocomposites were prepared by co‐coagulating NR latex, montmorillonite aqueous suspension and cellulose xanthate. The clay was previously exfoliated in water, and the resulting suspension was then added to the mixture of NR latex with cellulose xanthate. Morphological, rheometric, mechanical, and dynamic mechanical properties were evaluated, and an increase in these properties was observed upon the addition of cellulose and clay nanomaterials to the rubber matrix. The results show the advantage in using cellulose as a nanopolymer as well as MMT as nanofiller. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

石墨烯/室温硫化硅橡胶复合材料的制备及性能

采用水合肼对氧化石墨进行还原获得石墨烯,通过高速剪切分散法将石墨烯分散到α,ω-羟基聚二甲基硅氧烷中,固化后得到石墨烯/室温硫化(RTV)硅橡胶复合材料。对石墨烯和复合材料的微观形貌进行了表征,并考察了复合材料的性能。结果表明,所制备石墨烯的厚度为1～3 nm,为具有较少层数的石墨烯片层结构;复合材料断面呈微相分离结构,但其差示扫描量热曲线只有1个玻璃化转变温度(Tg)。随着石墨烯用量的增加,复合材料的Tg升高,结晶熔点降低。石墨烯对RTV硅橡胶有增强作用,当石墨烯的质量分数为0.5%时,复合材料的拉伸强度达到0.35 MPa,较纯RTV硅橡胶的拉伸强度提高了67%。     

溴化丁基橡胶/有机蒙脱土纳米复合材料的制备和性能研究

用机械共混法制备了剥离型溴化丁基橡胶/有机蒙脱土(BIIR/OMMT)纳米复合材料。OMMT可使溴化丁基橡胶的正硫化时间缩短,却不影响焦烧安全性,达到了节能降耗的目的。OMMT的加入还可使耐溶剂性能和耐热性能显著提高,其含量仅为3.0 phr时,拉伸强度和撕裂强度分别提高了90.8%和81.4%。     

Morphology,thermal, and mechanical properties of flame‐retardant silicone rubber/montmorillonite nanocomposites

Flame‐retardant methyl vinyl silicone rubber (MVMQ)/montmorillonite nanocomposites were prepared by solution intercalation method, using magnesium hydroxide (MH) and red phosphorus (RP) as synergistic flame‐retardant additives, and aero silica (SiO₂) as synergistic reinforcement filler. The morphologies of the flame‐retardant MVMQ/montmorillonite nanocomposites were characterized by environmental scanning electron microscopy (ESEM), and the interlayer spacings were determined by small‐angle X‐ray scattering (SAXS). In addition to mechanical measurements and limited oxygen index (LOI) test, thermal properties were tested by thermogravimetric analysis (TGA). The decomposition temperature of the nanocomposite that contained 1 wt % montmorillonite can be higher (129°C) than that of MVMQ as basal polymer matrix when 5% weight loss was selected as measuring point. This kind of silicone rubber nanocomposite is a promising flame‐retardant polymeric material. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3275–3280, 2006     

Synthesis and properties of silicone rubber/organomontmorillonite hybrid nanocomposites

In this article, silicone rubber/organomontmorillonite hybrid nanocomposites were prepared via a melt-intercalation process. The resulting hybrid nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The results proved that the organomontmorillonite could be exfoliated into ca. 50-nm thickness and uniformly dispersed in the silicone rubber matrix during the melt-intercalation process. Furthermore, the mechanical properties and thermal stability of the hybrids were very close to those of aerosilica-filled silicone rubber. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1557–1561, 1998     

铂催化剂用量对室温硫化发泡硅橡胶结构和性能的影响

在铂催化剂条件下,通过硅氢加成反应和硅氢缩合脱氢反应制备了双组分室温硫化发泡硅橡胶。研究结果表明:铂催化剂影响产物的结构和性能,当催化剂的含量为1 200 mg/kg时,热性能较好,初始分解温度达到494℃,1 000℃残炭率达到71.66%,热导率达到0.092 W·(mK)~(-1)。通过扫描电镜观察到泡孔尺寸变小,分布变窄。     

乳液法天然橡胶/丁腈橡胶/蒙脱土纳米复合材料的结构与性能

采用乳液法制备了天然橡胶/丁腈橡胶/蒙脱土纳米复合材料,考察了其微观形态,探讨了复合材料的硫化特性及静态和动态力学性能.结果表明,蒙脱土以纳米尺寸均匀分布于丁腈橡胶基质中,橡胶分子链并未插层进入蒙脱土片层;蒙脱土使复合材料的焦烧时间和正硫化时间增加,可明显提高复合材料的静态力学性能;复合材料具有与天然橡胶/丁腈橡胶共混...     

天然橡胶／有机蒙脱土纳米复合材料的阻隔效应

用自制的有机蒙脱土(OMMT)通过机械共混法制备了剥离型天然橡胶(NR)/OMMT纳米复合材料,用热解重量分析法、溶剂渗透性测试和气体阻隔性测试研究了材料的耐热性、耐油性和气体阻隔性.结果表明,由于蒙脱土片层的阻气和隔热作用,纳米复合材料的失重起始温度明显升高,耐热性能得到改善.在标准溶剂油中浸泡9 h后,填充3份(质量)OMMT的纳米复合材料的溶胀指数比纯NR试样降低了25.1%,常温耐油性能明显改善;其氧气渗透率较纯NR试样降低了49.4%.借助透射电子显微镜照片制作的示意图分析了OMMT片层阻隔效应的原理.     

SEBS/蒙脱土纳米复合材料结构和性能研究

采用溶液混合方法制备了氢化苯乙烯/丁二烯三元嵌段共聚物(SEBS)/有机蒙脱土(OM-MT)纳米复合材料(NC)。对SEBS/OMMT NC的插层结构和物理力学、动态力学、耐热等性能进行了研究。结果表明,与SEBS复合,OMMT层间距明显增大,制备出具有插层型结构的NC。加入OMMT可明显提高SEBS的拉伸断裂强度、300%定伸强度和断裂伸长率,但永久变形也增大。DMA研究表明,SEBS/OMMT NC的储能模量和损耗模量比纯SEBS显著提高,PEB链段的tanδ降低,而PS链段增加。SEBS/OMMT NC比SEBS的热稳定性明显提高。     

顺丁橡胶/有机蒙脱土纳米复合材料的结构与性能

采用溶液法制得了顺丁橡胶(BR)有/机蒙脱土(OMMT)纳米复合材料,并用X射线衍射仪、透射电子显微镜对复合材料的结构进行了表征,研究了复合材料的应力-应变行为和耐油性能。结果表明,OMMT的层间距增大,制得了插层型纳米复合材料;在较高的应变下,BR/OMMT纳米复合材料的扯断伸长率和拉伸强度随OMMT用量的增大而增加;当OMMT用量小于9份时,BR/OMMT纳米复合材料的耐油性能随OMMT用量的增加而有所提高。     

动态硫化聚氨酯/硅橡胶热塑性弹性体研究进展

从原料选择、加工工艺和增容剂方面总结了动态硫化聚氨酯/硅橡胶热塑性弹性体的研究进展。     

PA6/蒙脱土熔融插层复合材料结构与性能分析

通过熔融共混法插层复合制备了聚酰胺(PN)6／蒙脱土纳米复合材料，测试了力学性能并对不同蒙脱土含量的PA 6／蒙脱土纳米复合材料进行了对比。实验表明，通过熔融插层可使PN 6基体插层于蒙脱土中，所得到的复合材料的性能较PN 6有很大提高。蒙脱土特殊的层状结构使得利用熔融共混在机械力的作用下插层到纳米级复合材料成为可能。