纳米填料填充氢化丁腈橡胶的性能及压缩形态特征

研究了不同的炭黑( N 330,N 550,N 770,N 990) 、甲基丙烯酸锌及炭黑N 770 与甲基丙烯酸锌并用填充氢化丁腈橡胶( HNBR) 的性能,用橡胶加工分析仪和透射电镜分析了填料的分散性、形态变化及其与胶料压缩永久变形的关系。结果表明,随炭黑粒径增大,胶料的力学性能有所降低,Payne 效应减小( 即炭黑的分散性变好) ,压缩永久变形减小。炭黑填充胶料具有较好的耐热老化和耐油性能,相比较而言,炭黑N 770 填充胶料的综合性能最好。在填充30 份( 质量) 炭黑N 770 的HNBR 中并用适量的甲基丙烯酸锌,随其用量增加胶料的强度和扯断伸长率明显增大,压缩永久变形增大,Payne 效应变化不大。透射电镜分析结果表明,高温下长时间压缩后,炭黑粒子间的距离缩短,粒子有聚集现象,但粒子本身未发生变形。这表明炭黑填充胶料的压缩永久变形主要源于橡胶分子结构的变化、炭黑粒子的聚集及分布状态的变化。聚甲基丙烯酸锌在HNBR 中的纳米分散性优异。由于压缩后该离聚体粒子易产生滑移、变形和明显的聚集现象,对大分子网络弹性恢复的阻碍作用远高于炭黑,因而胶料的压缩永久变形比炭黑填充者要大得多。     

ZDMA/白炭黑填充HNBR的结构与性能

以甲基丙烯酸锌(ZDMA)/白炭黑填充氢化丁腈橡胶(HNBR),研究ZDMA/白炭黑并用比、硫化剂DCP用量及硫化时间对HNBR硫化胶结构和性能的影响。结果表明,在填料总量不变的前提下,随着白炭黑用量的增大,ZDMA/白炭黑填充HNBR硫化胶拉伸强度和压缩永久变形先减小后增大,填料分散性下降;随着硫化剂DCP用量的增大,ZDMA/白炭黑填充HNBR硫化胶物理性能和动态性能提高,填料分散性变好。当ZDMA/白炭黑并用比为10/30、硫化剂DCP用量为5～6份、一段硫化条件为160℃×45min、二段硫化条件为150℃×(9～12)h时,ZDMA/白炭黑填充HNBR硫化胶综合性能较好。     

原位合成甲基丙烯酸锌增强氢化丁腈橡胶

用ZnO和甲基丙烯酸(MAA)经原位反应合成了甲基丙烯酸锌(ZDMA),将其作为增强剂用以增强氢化丁腈橡胶(HNBR),研究了ZnO／MAA(摩尔比,下同)、过氧化二异丙苯(DCP)用量和ZDMA用量对硫化胶力学性能的影响。结果表明,当ZnO／MAA为0．8,DCP用量为4份(质量,下同)时,原位合成ZDMA能够显著地提高HNBR的力学性能。随着ZDMA理论生成量的增加,硫化胶的拉伸强度先增加后减少,当ZDMA理论生成量为30份时,硫化胶的最大拉伸强度为47.2MPa．而扯断伸长率保持在393％以上;100％定伸应力随ZDMA理论生成量的增加而增加。经傅里叶变换红外光谱法和广角X光衍射法分析表明,在HNBR混炼过程中,ZnO和MAA可以原位生成ZDMA。     

增强氢化丁腈橡胶的结构与性能

研究了甲基丙烯酸锌(ZDMA)、SiO,和炭黑N 550分别填充氢化丁腈橡胶(HNBR)的流动性、硫化特性、物理机械性能、耐老化性能、压缩永久变形及动态力学性能,表征了填料在HNBR混炼胶及硫化胶中的形态结构.结果表明,3种填料填充的HNBR混炼胶均属非牛顿流体,其中ZDMA填充HNBR混炼胶具有较好的流动性;经过二段硫化后.3种填料填充HNBR具有较佳的物理机械性能、耐老化性能和耐压缩性能;zDMA和SiO2,对HNBR的增强效果显著,但HNBR硫化胶的压缩永久变形偏高,N 550填充HNBR硫化胶的扯断伸长率和压缩永久变形较低;SiO2填充HNBR混炼胶和硫化胶的Payne效应较ZDMA、N 550填充HNBR混炼胶和硫化胶显著;N 550、SiO2种填料在HNBR混炼胶和硫化胶中均能达到纳米尺度,ZDMA在HNBR混炼胶中呈微米尺度,而在HNBR硫化胶中呈纳米尺度.     

甲基丙烯酸锌增强弹性体的相态研究 II.硫化胶料(英文)

利用扫描电子显微镜(SEM)和透视电子显微镜(TEM)研究了甲基丙烯酸锌增强多种弹性体(包括BR,SBR,EPDM,NBR,EPM,POE和HNBR)的微观相态结构。发现在各体系的硫化胶料中均存在两类基本分散结构:纳米分散结构和微米分散结构。其中纳米增强结构是在胶料过氧化物交联过程中由ZDMA原位聚合生成的;而微米结构就是残余的ZDMA颗粒。这两种结构的尺寸及相对含量因不同的复合体系而不同。对于BR和SBR体系,其微米分散结构较其他体系更多,且纳米分散结构的尺寸相对略小。而在EPDM,NBR,EPM,POE,HNBR中,微米分散结构较少,且纳米分散结构的尺寸相对较大。还研究了ZDMA颗粒的原生尺寸对硫化胶料的相态结构的影响,发现在POE体系,较大的ZDMA原生尺寸将造成其硫化胶料中微米分散结构的大量增多;而EPDM,EPM,NBR,HNBR胶料的相态则对ZDMA原生尺寸的变化不敏感。硫化胶料的微观相态的差异必将对其物理机械性能产生直接的影响。     

甲基丙烯酸锌增强弹性体的相态研究Ⅱ.硫化胶料

利用扫描电子显微镜（SEM）和透视电子显微镜（TEM）研究了甲基丙烯酸锌增强多种弹性体（包括BR，SBR，EPDM，NBR，EPM，POE和HNBR）的微观相态结构。发现在各体系的硫化胶料中均存在两类基本分散结构：纳米分散结构和微米分散结构。其中纳米增强结构是在胶料过氧化物交联过程中由ZDMA原位聚合生成的；而微米结构就是残余的ZDMA颗粒。这两种结构的尺寸及相对含量因不同的复合体系而不同。对于BR和SBR体系，其微米分散结构较其他体系更多，且纳米分散结构的尺寸相对略小。而在EPDM，NBR，EPM，POE，HNBR中，微米分散结构较少，且纳米分散结构的尺寸相对较大。还研究了ZDMA颗粒的原生尺寸对硫化胶料的相态结构的影响，发现在POE体系，较大的ZDMA原生尺寸将造成其硫化胶料中微米分散结构的大量增多；而EPDM，EPM，NBR，HNBR胶料的相态则对ZDMA原生尺寸的变化不敏感。硫化胶料的微观相态的差异必将对其物理机械性能产生直接的影响。     

A comparative study of aging characteristics and thermal stability of oil palm ash,silica, and carbon black filled natural rubber vulcanizates

Filler‐filled natural rubber (NR) vulcanizates were prepared by conventional laboratory‐sized two roll mills and cured using sulfuric system. The effect of thermal aging on physical properties and thermogravimetric analysis (TGA) of oil palm ash (OPA) and commercial fillers (i.e., silica vulkasil C and carbon black N330)‐filled NR vulcanizates at respective optimum loading and equal loading were studied. Before aging, the OPA‐filled vulcanizates showed comparable optimum strength as carbon black‐filled vulcanizates. The hardening of aged filler‐filled NR vulcanizates happened after aging, thereby tensile strength and elongation at break reduced while the modulus increased. Fifty phr carbon black‐filled vulcanizates showed better retention in tensile properties as compared to silica (10 phr) and OPA (1 phr). This was attributed to the addition of different filler loading and this finding was further explained when equal loading of filler‐filled vulcanizates was studied. Fourier transform infra‐red analysis showed chemical structure had changed and tensile fractured surface exhibited smooth appearance due to the deterioration in tensile properties after aging. TGA also denoted the thermal stability was depending on the amount of filler loading. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4474–4481, 2013     

Effects of Carbon Black on the Properties of HNBR Reinforced by in-situ Prepared ZDMA

Hydrogenated nitrile rubber (HNBR) filled with carbon black (CB) and in-situ prepared zinc dimethacrylate (ZDMA) was prepared by mechanical mixing method. The effects of carbon black on the vulcanization characteristics, physical and dynamic mechanical properties, thermal stability and the fracture surface morphologies of HNBR reinforced by in-situ prepared ZDMA (HNBR/ZDMA) were investigated. The results showed that, for given ZDMA loading (50 phr), with the increasing CB content, the scorch time extended, tensile strength, tear strength and elongation at break increased at first and then decreased, while the modulus at 100% and hardness increased. The comprehensive properties of the HNBR/ZDMA/CB was optimal, when the content of CB was 10 phr. DMA analysis showed that the addition of CB could enhance the storage modulus (E’) & loss modulus (E”), and decreased the glass transition temperature (Tg) of HNBR/ZDMA. TGA analysis revealed that the addition of CB could improve the thermal stability of HNBR/ZDMA. SEM analysis showed that the CB dispersed well in the HNBR/ZDMA, and the CB could improve the dispersion of ZDMA effectively.     

HNBR4种补强填充体系的研究

分别研究了炭黑N330,炭黑N550,炭黑N660和炭黑N774对氢化丁腈橡胶（HNBR）硫化特性和力学性能的影响,并考察了4种炭黑在HNBR中的分散度和Payne效应。结果表明,炭黑N550的胶料焦烧时间和正硫化时间均最长,分散度最好。随着炭黑粒径的逐渐增大,硫化胶拉伸强度、定伸应力和硬度均逐渐减小,拉断伸长率却逐渐增大。4种炭黑胶料的Payne效应强弱顺序为炭黑N330〉炭黑N550〉炭黑N660〉炭黑N774。     

Mechanical properties,chemical and aging resistance of natural rubber filled with nano‐Al2O3

Al₂O₃ nanoparticles were introduced to natural rubber (NR) to investigate its reinforcement effect on filled NR vulcanizates. The results show that Nano‐Al₂O₃/NR nanocomposites exhibit significantly improved tensile strength, elongation at break, modulus, and tearing strength. Scanning electron microscopy analyses indicate that nanoparticles dispersed in NR matrix at nanoscale and show nano‐reinforcement effect on NR vulcanizates. The aging resistances of filled NR vulcanizates improve. After aging test, tensile strength, tearing strength, and modulus improved, and elongation at break decreased. These attribute to the crosslink maturation reactions, which result in the conversion of polysulfidic linkages into disulfidic and monosulfidic ones. The acid and alkaline resistances of nano‐Al₂O₃‐filled NR vulcanizates improve compared with that of unfilled NR systems. After acid and alkaline test, tensile strength and elongation at break improve, and modulus decrease. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Fabrication,characterization, and properties of poly(ethylene‐co‐vinyl acetate)/magnetite nanocomposites

Poly(ethylene‐co‐vinyl acetate) (EVA)/magnetite (Fe₃O₄) nanocomposite was prepared with different loading of Fe₃O₄ nanoparticles. The mixing and compounding were carried out on a two‐roll mixing mill and the sheets were prepared in a compression‐molding machine. The effect of loading of nanoparticles in EVA was investigated thoroughly by different characterization technique such as transmission electron microscopy (TEM), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), limiting oxygen index (LOI), and technological properties. TEM analysis showed the uniform dispersion of filler in the polymer matrix and the dispersion of filler decreased with increase in filler content. XRD of the nanocomposite revealed the more ordered structure of the polymer chain. An appreciable increase in glass transition temperature was observed owing to the restricted mobility of Fe₃O₄‐filled EVA nanocomposite. TGA and flame resistance studies indicated that the composites attain better thermal and flame resistance than EVA owing to the interaction of filler and polymer segments. Mechanical properties such as tensile strength, tear resistance, and modulus were increased for composites up to 7 phr of filler, which is presumably owing to aggregation of Fe₃O₄ nanoparticle at higher loading. The presence of Fe₃O₄ nanoparticles in the polymer matrix reduced the elongation at break and impact strength while improved hardness of the composite than unfilled EVA. The change in technological properties had been correlated with the variation of polymer–filler interaction estimated from the swelling behavior. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40116.     

甲基丙烯酸锌增强弹性体的相态研究Ⅰ.混炼胶料

利用扫描电子显微镜（SEM）和透视电子显微镜（TEM）研究了甲基丙烯酸锌增强多种弹性体（包括BR，SBR，EPDM，NBR，EPM，POE和HNBR）的微观相态结构。发现混炼胶在混炼工艺中所具有的粘度是决定ZDMA粒子在混炼胶中分散状态的主要因素，对于高粘度胶料，如EPDM和NBR体系，在混炼中ZDMA颗粒的尺寸显著减小，部分甚至达到了纳米级，而对于低粘度胶料，如POE体系，ZDMA的尺寸特征在混炼工艺中基本不变。由于ZDMA在橡胶中的原位聚合反应历程与其分散尺寸密切相关，所以这种ZDMA在混炼胶料中初分散状态的不同必然会对其硫化化胶料的最终相态和性能产生重大的影响。     

Cure characteristics and mechanical properties of styrene-butadiene rubber/hydrogenated acrylonitrile-butadiene rubber/silica composites

Composites of styrene butadiene rubber (SBR), hydrogenated acrylonitrile–butadiene rubber (HNBR) and silica were prepared. Sulfur (S), dicumyl peroxide (DCP) and a combination of S and DCP (M) were used as curing agents, respectively. The morphology of the composites with different blend ratio was examined to correlate with observations on mechanical properties by scanning electron microscopy. The effects of blend ratio and curing systems on the curing characteristics and mechanical properties, such as stress–strain behavior, tensile strength, elongation at break and hardness of SBR/HNBR/Silica composites, were studied. Composites prepared by M curing systems showed comparatively better mechanical properties, wet traction and rolling resistance than S and D curing systems. The tensile strength, tear strength, and elongation at break were improved by adding HNBR for M curing systems. The wet traction of the vulcanizates containing HNBR was better than that of the vulcanizates without HNBR. A relatively uniform dispersion of silica was observed for SBR/HNBR/silica compositions compared with SBR/silica composites.     

In situ reactive compatibilization and reinforcement of peroxide dynamically vulcanized polypropylene/ethylene‐propylene‐diene monomer tpv by zinc dimethacrylate

This work demonstrates an approach of in situ reactive compatibilization between polypropylene (PP) and ethylene‐propylene‐diene monomer (EPDM) by using ZDMA as a compatibilizer and, simultaneously, as a very strong reinforcing agent. With 7phr ZDMA in the PP/EPDM (30/70, w/w) thermoplastic vulcanizate (TPV), the tensile strength and elongation at break were increased from 5.3 MPa and 222% up to 11.2 MPa and 396%, respectively. Increasing the PP concentration further improved mechanical properties of the TPVs with ZDMA. This tremendous reinforcing as well as the compatibilization effect of the ZDMA was understood by polymerization of ZDMA and ZDMA reacting with EPDM and PP during peroxide induced dynamic vulcanization. A peculiar nano‐composite structure that the crosslinked rubber particles were “bonded” by a transition zone which containing numerous of nano‐particles with dimensions of about 20–30 nm was observed from transmission electron microscopy (TEM). Scanning electron microscopy (SEM) results showed that increase of PP/EPDM ratio reduced the size of crosslinked EPDM particles. Moreover, we found that the ZDMA reinforced EPDM particles resulted in a higher tan δ peak temperature for EPDM phase and built “filler‐filler”‐like networking in the PP melt. POLYM. COMPOS. 34:1357–1366, 2013. © 2013 Society of Plastics Engineers     

Effect of filler size distribution on the mechanical and physical properties of alumina‐filled silicone rubber

The properties of silicone rubber filled with three kinds of binary mixtures of alumina particles with different size distribution (i.e., 30 μm + 0.5 μm, 10 μm + 0.5 μm, and 5 μm + 0.5 μm) were investigated as a function of relative volume fraction of the 0.5 μm particles in the hybrid alumina (V_s) at a fixed total filler content of 55 vol%. The results indicate that each binary mixture of alumina‐filled silicone rubber exhibited improved thermal conductivity and tensile strength, and decreased dielectric constant, compared to a single particle size filler‐reinforced one, and the maximum improvements were obtained at the V_s ranging from 0.2 to 0.35; the coefficient of thermal expansion (CTE) of filled silicone rubber obviously reduced with increase in the V_s, whereas the elongation at break slightly decreased. At V_s = 0, the larger particles‐filled silicone rubber showed higher thermal conductivity, CTE, dielectric constant, and elongation at break, and lower tensile strength compared with the those of the smaller particles‐filled one. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

THE COMPARISON PROPERTIES OF RECYCLE RUBBER POWDER,CARBON BLACK,AND CALCIUM CARBONATE FILLED NATURAL RUBBER COMPOUNDS

The effects of filler loading on the curing characteristics, swelling behavior, and mechanical properties of natural rubber compounds were studied using a conventional vulcanization system. Recycle rubber powder (RRP), carbon black (CB) (N550), and calcium carbonate (CaCO₃) were used as fillers and the loading range was from 0 to 50 phr. Results show that the scorch time, t ₂, and cure time, t ₉₀, decrease with increase in filler loading. At a similar filler loading, RRP shows shortest t ₂ and t ₉₀ followed by CB and calcium carbonate. The tensile strength, tensile modulus, and hardness increase with increase in CB loading, whereas elongation at break, resilience, and swelling properties show opposite trend. For RRP and calcium carbonate filled natural rubber compounds, the tensile strength increases up to 10 phr and starts to deteriorate at higher filler loading. The other properties such as tensile modulus, hardness, elongation at break, resilience, and swelling percentage show a small change (increase or decrease) with increase in RRP and calcium carbonate loading in natural rubber compounds. Overall results indicate that RRP can be used as a cheapener to replace calcium carbonate in natural rubber compounds where improved mechanical properties are not critical.     

Influence of Particle Type and Silane Coupling Agent on Properties of Particle-Reinforced Styrene-Butadiene Rubber

Silica- and carbon-filled styrene butadiene rubber (SBR) were prepared. The influence of particle type and silane coupling agent on cure characteristics, physical and dynamic mechanical properties of particle-reinforced SBR were investigated. Minimum torque, maximum torque and tensile strength increased with increase of the filler content. The tensile strength and elongation at break were highest for presence of bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT) in silica-filled vulcanizates. The dynamic mechanical properties show that tan δ at temperatures of ?20–0°C of the SiO₂/TESPT/SBR vulcanizate was highest of all. Tan δ at temperatures of 50–70°C of the SiO₂/TESPT/SBR vulcanizate was lower than carbon-filled SBR.     

Utilization of bowstring hemp fiber as a filler in natural rubber compounds

The cure characteristics and physicomechanical properties of natural rubber (standard Nigerian rubber) vulcanizates filled with the fiber of bowstring hemp (Sansevieria liberica) and carbon black were investigated. The results showed that the scorch and cure times decreased, whereas the maximum torques increased, with increasing filler loadings for both bowstring hemp fiber and carbon black filled vulcanizates. The tensile strength of both bowstring hemp fiber and carbon black filled vulcanizates increased to a maximum at a 40 phr filler concentration before decreasing. The elongation at break and rebound resilience decreased, whereas the modulus, specific gravity, abrasion resistance, and hardness increased, with increasing filler contents. The carbon black/natural rubber vulcanizates had higher tensile strength, which was about 1.5 times that of bowstring hemp fiber/natural rubber vulcanizates. This superiority in the tensile strength was probably due to the higher moisture content and larger particle size of the bowstring hemp fiber. However, the bowstring hemp fiber/natural rubber vulcanizates showed superior hardness. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

On the potential of organoclay with respect to conventional fillers (carbon black,silica) for epoxidized natural rubber compatibilized natural rubber vulcanizates

Onium modified montmorillonite (organoclay) was compounded with natural rubber (NR) in an internal mixer and cured by using a conventional sulfuric system. Epoxidized natural rubber with 50 mol % epoxidation (ENR 50) in 10 parts per hundred rubber (phr) was used as a compatibilizer in this study. For comparison purposes, two commercial fillers: carbon black (grade N330) and silica (grade vulcasil‐S) were used. Cure characteristics were carried out on a Monsanto MDR2000 Rheometer. Organoclay filled vulcanizate showed the lowest values of torque maximum, torque minimum, scorch, and cure times. The kinetics of cure reaction showed organoclay could behave as a cocuring agent. The mechanical testing of the vulcanizates involved the determination of tensile and tear properties. The improvement of tensile strength, elongation at break, and tear properties in organoclay filled vulcanizate were significantly higher compared to silica and carbon black filled vulcanizates. In terms of reinforcing efficiency (RE), organoclay exhibited the highest stiffness followed by silica and carbon black filled vulcanizates. Scanning electron microscopy revealed that incorporation of various types of fillers has transformed the failure mechanism of the resulting NR vulcanizates compared to the gum vulcanizates. Dynamic mechanical thermal analysis (DMTA) revealed that the stiffness and molecular relaxation of NR vulcanizates are strongly affected by the filler–rubber interactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2438–2445, 2004     

Some interesting phenomena in silica‐filled HNBR with the addition of silane coupling agent

Hydrogenated nitrile rubber (HNBR)/silica nanocomposites were prepared by in‐situ modification dispersion technology, and the silane coupling agent γ‐methacryloxypropyl trimethoxy silane (KH570) was chosen to promote the interfacial strength between silica particles and HNBR matrix and further improve the dispersion of silica particles. Rubber Process Analyzer (RPA2000) was used to test the Payne effect of HNBR/silica compounds, from which some interesting phenomena were found: the Payne effect became stronger after KH570 was added to HNBR/silica compound at room temperature, which was a contrary result compared to SBR/silica system. However, after stored for a month at room temperature, the Payne effect weakened, which was contrary to the traditional phenomenon of storage hardening of filled rubber. All these results are related to filler–filler interaction and filler–rubber interaction. The modulus at small strain amplitude of HNBR/silica compound with KH570 gradually decreased with the increase of times of circulatory strain sweep but that of compound without KH570 had almost no change, which was explained by Fourier Transform Infrared (FTIR) results that the reaction between silica and KH570 almost completed at the test condition: 80°C and about 1 h. The effects of silane amount, heat‐treated temperature and time on the Payne effect of compounds and the mechanical properties of vulcanizates were also investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012