Effects of silane coupling agent and maleic anhydride‐grafted polypropylene on the morphology and viscoelastic properties of polypropylene–mica composites

In this study, morphology, and dynamic and mechanical properties of polypropylene–mica (PP–Mica) composites were investigated. To enhance the adhesion between PP and mica, maleic anhydride‐grafted PP (MAPP) and treated mica with silane coupling agent were used. MAPP (as a compatibilizer) and silane coupling agent (as a filler surface modifier) caused an interfacial bonding in the mica filled polypropylene composites. The effect of mica content, MAPP, and treated mica with silane coupling agent on the morphological properties were investigated by Scanning Electron Microscopy (SEM). The results showed that with increasing MAPP or silane coupling agent, dispersion of filler and adhesion between PP and filler were improved. Mechanical data showed that with increasing MAPP and mica treated with silane coupling agent, tensile modulus and flextural strength of composites were enhanced. Dynamic rheological behavior of composites was also investigated within the domain of linear viscoelasticity. The rheological observations indicated that the complex viscosity, storage and loss moduli increased, and tan δ decreased with increasing mica content. POLYM. COMPOS. 27:491–496, 2006. © 2006 Society of Plastics Engineers.     

Influence of untreated and novel electron‐beam‐modified surface‐coated silica filler on the thermorheological properties of ethylene–octene copolymer

We developed surface‐modified silica fillers by coating these with an acrylate monomer, trimethylolpropane triacrylate, or a silane coupling agent, triethoxyvinyl silane, followed by electron‐beam irradiation at room temperature. These were incorporated in an ethylene–octene copolymer rubber. Thermorheological studies of the unvulcanized ethylene–octene copolymer and its untreated and modified silica‐filled composites were done with a shear dynamic oscillating rheometer. Modification of the silica filler, especially via the silanization process followed by electron beam treatment, significantly reduced filler–filler networking as revealed from the log–log plots of storage modulus and complex shear viscosity, and its real component. The rheological complexity of the compositions was analyzed from a double logarithmic plot of the storage modulus and loss modulus. The results obtained from the master curves constructed on the basis of the time–temperature superposition principle and the activation energy calculated from the Arrhenius equation for the flow of above these compounds further supported these findings. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2453–2459, 2003     

Mechanical and rheological properties of reinforced polyethylene

The rheological and mechanical properties of a high density polyethylene (HDPE) filled with surface-treated mica flakes are reported. Young's modulus decreases with different treatments, whereas break elongation and maximum strength slightly increase. Young's modulus increases with the addi ion of mica flakes, but the decrease in elongation is also quite significant. For 20% mica composites, hardly any change was observed in the properties. The high shear viscosity does not show any significant effect as a result of the surface treatment. Viscosity of composites increases with silane treatment and decreases with titanate treatment. It is suggested that the coupling agent, depending on its chemical structure and nature of the filler, may act as an adhesion promoter or as a lubricating agent.     

An investigation on the mechanical and dynamic rheological properties of single and hybrid filler/polypropylene composites based on talc and calcium carbonate

Some results of experiments on the mechanical and rheological properties of mineral filled polypropylene were presented. Single filler and hybrid filler composites of talc and calcium carbonate (CaCO₃) were prepared in a co‐rotating twin‐screw extruder. The effect of filler type, filler content, and coupling agent on the mechanical and rheological properties of the polypropylene were studied. The coupling agent was maleic anhydride‐grafted polypropylene (PP‐g‐MA). It was found that the mechanical properties are affected by filler type, filler concentration, and the interaction between filler and matrix. The tensile strength of the composite is more affected by the talc while the impact strength is influenced mostly by CaCO₃ content. The elongation at break of PP/CaCO₃ composites was higher than that of PP/talc composites. The incorporation of coupling agent into PP/mineral filler composites increased the mechanical properties. Rheological properties indicated that the complex viscosity and storage modulus of talc filled samples were higher than those of calcium carbonate filled samples while the tan δ was lower. The rheological properties of hybrid‐filler filled sample were more affected by the talc than calcium carbonate. The PP‐g‐MA increased the complex viscosity and storage modulus of both single and hybrid composites. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers     

The role of additional silane coupling agent treatment in oxygen plasma-treated UHMPE fiber/vinylester composites

Ultra-high modulus polyethylene (UHMPE) fiber was treated with oxygen plasma and a silane coupling agent in order to improve the interfacial adhesion between the UHMPE fiber and vinylester resin. The oxygen plasma and γ-methylmethacryloxypropyltrimethoxysilane (γ-MPS)-treated UHMPE fiber/vinylester composites showed a slightly higher interlaminar shear strength than the oxygen plasma-treated UHMPE fiber/vinylester composites. The interfacial adhesion of the oxygen plasma-treated UHMPE fiber/vinylester composites in this study is mainly due to mechanical interlocking between the micropits formed by the oxygen plasma treatment and the vinylester resin. The γ-MPS molecules adsorbed onto the UHMPE fiber surface neither affected the morphology of the UHMPE fiber surface, nor reduced the extent of mechanical interlocking. The improved interfacial adhesion by the γ-MPS treatment is due to enhanced wettability and chemical interaction through the chemically adsorbed γ-MPS molecules, as detected by Fourier-transform infrared (FT-IR) spectroscopy. The γ-MPS molecules adsorbed onto the ultra-high molecular weight polyethylene (UHMWPE) plate surface also reduced the aging effect of the oxygen plasma-treated UHMWPE surface.     

脱醇型室温硫化硅橡胶的制备

以α,ω-二羟基聚二甲基硅氧烷为基胶,氨基硅烷JT-908为封端剂,添加气相法二氧化硅、交联剂、硅烷偶联剂和催化剂制得脱醇型室温硫化硅橡胶,研究了封端剂和气相法二氧化硅用量、催化剂种类和用量、硅烷偶联剂种类对硅橡胶性能的影响.结果表明,封端剂的较佳用量为4份,气相法二氧化硅的较佳用量为10份,催化剂选择二月桂酸二丁基锡...     

单组分脱醇型密封胶的研制

以端羟基聚二甲基硅氧烷(107硅橡胶)为基胶、甲基三甲氧基硅烷和乙烯基三甲氧基硅烷为交联剂、纳米碳酸钙和气相法白炭黑为补强填料、硅烷偶联剂为增粘剂,有机钛为催化剂,制得单组分脱醇型室温硫化(RTV-1)硅橡胶。研究了基胶黏度,填料、交联剂、增粘剂的种类和用量对脱醇型RTV-1硅橡胶性能的影响。较佳配方为:100份黏度50 000 mm2/s的107硅橡胶、5份甲基三甲氧基硅烷与乙烯基三甲氧基硅烷按质量比7∶3复配的交联剂、0.4～0.6份自制氨基硅烷偶联剂。按此配方制得的RTV-1硅橡胶的性能较好。     

Effect of fillers on thermoplastic 1,2-polybutadiene rubber: Mechanical and viscoelastic properties

The effects of silica, carbon black, and china clay on the mechanical properties of 1,2-polybutadiene have been investigated. They include stress–strain behavior, tensile strength, elongation, tear strength, tension set, impact strength, and hysteresis. The effect of silane coupling agent on these properties has also been studied. The stress–relaxation behavior of the filled and unfilled systems has also been compared. The rate of relaxation increases with temperature. The dynamic mechanical properties have been determined using a Rheovibron viscoelastometer at 35 Hz at different temperatures. The storage and loss moduli are enhanced by addition of fillers. Silane coupling agent increases storage modulus as well as tan δ_max of the clay-filled polymer. The suitability of Voigt and Reuss models in predicting the composite moduli is examined.     

聚碳酸酯微粉/气相白炭黑杂化增强硅橡胶

利用磨盘形力化学反应器常温粉碎制备了聚碳酸酯（PC）微粉，在硅橡胶的常规补强体系中，引入PC微粉部分代替白炭黑，实现了对硅橡胶的杂化增强，在一定程度上改善了硅橡胶复合材料的力学性能。考察了PC微粉添加量、粒径以及表面处理白炭黑对硅橡胶复合材料力学性能的影响。结果表明，用PC微粉部分代替白炭黑，可以大幅度提高硅橡胶复合材料的断裂伸长率，从230％提高到最大320％左右，撕裂强度从12．3kN／m提高到最大14．6kN／m，复合材料的硬度显著降低，从78降低至68，白炭黑经硅烷偶联剂处理后，硅橡胶复合材料的硬度减小为63。     

莫来石与沉淀法白炭黑填充丁苯橡胶复合材料的性能比较

在双辊开炼机中将未处理或用质量分数为3%的硅烷偶联剂A-189处理的莫来石粉体加入到丁苯橡胶(SBR)中制成复合材料.研究莫来石的加入量对SBR性能的影响,并与沉淀法白炭黑填充的SBR的性能进行了比较.结果表明,莫来石粉体对SBR表现出半增强特性;与沉淀法白炭黑填充的SBR相比,SBR/莫来石复合材料表现出良好的硫化特...     

Effect of plate-like glass fillers on the mechanical properties of dental nanocomposites

In this study, glass flakes were incorporated into the spherical nanosilica component of the dental composites and its effect on the mechanical properties of these composites was investigated. To achieve a good interfacial adhesion between matrix resin and fillers, the particles were surface treated with a silane coupling agent (γ-MPS). Composites with different plate-like and spherical nanoparticle contents were prepared and their mechanical properties, including flexural strength, flexural modulus and fracture toughness were measured. The morphology of the particles and fracture surface of the composites were studied by SEM. The distribution of the flakes in the composite was also monitored using EDXA. Statistical analysis of the data was performed with ANOVA and the Tukey’s post hoc test was at a significance level of 0.05. The results showed that the flexural modulus and fracture toughness of specimens were improved with increasing the glass flake content up to 15 vol % which then declined upon further increase due to the stacking of the flakes on each other. A good interfacial adhesion was observed between matrix resin and particles in the SEM micrographs. The results of this study suggest that incorporation of glass flakes into the dental composites containing spherical nanosilica particles may enhance their mechanical properties.     

Investigation of the dynamic mechanical behavior of polypropylene/(wood flour)/(kenaf fiber) hybrid composites

Polypropylene/(wood flour)/(kenaf fiber) hybrid composites were prepared in an internal mixer. Kenaf was considered as a fibrous filler and wood flour as a particulate filler. The lignocellulosic loading used was 50%. Dynamic mechanical thermal analysis properties such as storage modulus (E′), loss modulus (E″), damping factor (tan δ), and adhesion factor were evaluated. It was found that the adhesion factor could interpret the interfacial adhesion between lignocellulosic fillers and the plastic matrix macroscopically. This factor was affected by the type of filler used and the coupling agent concentration. The variation of storage modulus was affected more by the shape of the filler and the coupling agent concentration at higher temperatures than at temperatures below the glass transition. Owing to a higher probability of agglomeration in a sample containing 50 wt% of wood flour, the storage modulus and complex viscosity of this sample were higher than those of other samples. Cole‐Cole diagrams showed that the homogeneity of samples containing a higher amount of coupling agent was higher than that of samples with a lower concentration. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Investigation on the dynamic melt rheological properties of polypropylene/wood flour composites

The rheological behavior of polypropylene/wood flour (WF) composite was investigated at constant temperature over a wide range of frequencies using a mechanical compact rheometer operated in the dynamic mode. The effect of WF content, particle size, and coupling agent on melt rheological properties were investigated. The melt rheological data in terms of complex viscosity (η*), storage modulus (G′), loss modulus (G″), and loss tangent (tan δ) were studied and compared for different samples. It was found that complex viscosity increases with increasing wood content and coupling agent. Compatibilization using coupling agent increased both storage modulus and loss modulus, but the variation of storage modulus is more. By increasing wood content storage modulus increases. Complex viscosity, storage modulus, and loss modulus showed a minimum value by increasing of wood particle size. Tan δ decreases with increasing of wood content. Cole–Cole plot indicated that relaxation process changes with addition WF, coupling agent, and using different mesh size of wood. The Han plots revealed the sensitivity of rheological properties with composition at constant temperature. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Performance improvement of glass-fiber-reinforced polystyrene composite using a surface modifier. II. Mechanical properties of composites

The mechanical properties of glass-fiber-reinforced polystyrene composites were investigated with the variation of glass fiber content, surface treatment conditions, and silane coupling agents. γ-MPS, GPS, and poly(γ-MPS-co-stvrene) were used for the surface modification of glass fiber. Mechanical properties of glass-fiber-reinforced polystyrene composites increased with increasing the content of glass fiber. Poly(γ-MPS-co-styrene) was superior to γ-MPS and GPS in promoting the interfacial adhesion of glass fiber-reinforced polystyrene composites. The mechanical properties of composites were maximum at a low copolymer concentration when the γ-MPS content in the copolymer was high and vice versa. © 1996 John Wiley & Sons, Inc.     

表面改性氧化锆无机填料对齿科自酸蚀粘结剂性能的影响

用溶胶-凝胶法对氧化锆粉体表面包覆氧化硅,并用硅烷偶联剂γ-甲基丙烯酰氧丙基三甲氧基硅烷(γ-MPS)进行表面修饰,制备了齿科粘结剂用无机填料。以双酚A-甲基丙烯酸缩水甘油酯(Bis-GMA)单体、二甲基丙烯酸三乙二醇酯(TEGDMA)稀释剂、甲基丙烯酸-2-羟乙酯(HEMA)两性单体、10-(2-甲基丙烯酰氧基)磷酸单癸酯(10-MDP)酸蚀剂为主要成分,将改性过的氧化锆按照质量分数为1%~10%的比例进行填充,测试了自酸蚀粘结剂的粘结强度等性能。结果表明,当填料质量分数为2%时明显提高粘结剂的粘结性能,其粘结强度为(31.63±1.53) MPa;而当ZrO₂填充的质量分数增加到5%后,粘结强度开始下降。扫描电镜对粘结断面进行分析,发现随着ZrO₂填充量的提高,自酸蚀粘结剂对牙本质小管和复合树脂的渗入作用减弱,导致粘结性能下降。超景深显微镜对样本切片观察显示,粘结剂的存在可以明显缩小牙齿与复合树脂之间的缝隙。     

Effects of coupling agents on the rheological behavior and physical/mechanical properties of filled nylon 6

An investigation was made on the rheological behavior and physical/mechanical properties of highly filled nylon 6 composites with and without a coupling agent. As fillers, calcium carbonate and calcium silicate were used, and, as coupling agent, two silanes (Union Carbide, A1100 and Y9187) and two titanates (Kenrich Petrochemicals, KR-44 and KR-138) were used. It was found that all the coupling agents used increased the viscosities of the nylon/CaCO₃ system. However, the effect of the coupling agents on the viscosity of the nylon/CaSiO₃ system seems quite complex; namely, the titanate KR-44 decreased the melt viscosity of the nylon/CaSiO₃ composite, whereas the titanate KR-138S and the silane Y9187 increased it. In general, the effectiveness of the coupling agents in improving the physical/mechanical properties of the nylon/CaCO₃ and nylon/CaSiO₃ composites was marginal. A considerable decrease in glass transition was observed upon exposure of all samples to water, regardless of the type of filler and coupling agent.     

Nano-CaCO3/HDPE复合材料流变性能的研究

通过熔融共混法制备了纳米碳酸钙/高密度聚乙烯(nano-CaCO3/HDPE)复合材料,使用旋转流变仪研究了复合材料的动态流变性能。结果表明,当nano-CaCO3加入量≤4%(质量分数)时,随着nano-CaCO3含量的增加,nano-CaCO3/HDPE复合材料的储能模量、损耗模量和复数黏度均高于纯HDPE,并逐渐上升。     

Rheological study of mica-filled polypropylene as influenced by a coupling agent

The rheological behavior of mica-filled polypropylene (PP) composites was investigated within the domain of linear viscoelasticity. The effect of mica concentration and of a silane coupling agent on material functions such as the complex viscosity (η*), the storage modulus (G') and the loss modulus (G") was examined. The dimensions of mica flakes were measured before and after coating with silane. The affinity of PP for the treated and non-treated mica was characterized. It was found that, for low mica concentration (<30% by weight) the composite exhibits the classical viscoelastic behavior of a homogeneous material. For higher mica concentration, the material shows a strong heterogeneity as evidenced by an important drift at low frequencies in a Cole-Cole representation. It was also found that the presence of a silane coupling agent moves this critical concentration value up to 40% by weight.     

环氧化天然橡胶复合材料性能研究

采用新方法制备环氧化天然橡胶(ENR)/白炭黑和天然橡胶(NR)/ENR/白炭黑复合材料,并对其性能进行研究。结果表明:ENR/白炭黑复合材料的热稳定性优于ENR;在NR/ENR并用胶中加入白炭黑和硅烷偶联剂KH-550,NR/ENR/白炭黑复合材料0℃时的损耗因子(tanδ)增大,65℃时的tanδ值减小,复合材料的抗湿滑性能提高,滚动阻力减小。     

白炭黑与溶聚丁苯橡胶的键接位置对白炭黑/炭黑/溶聚丁苯橡胶复合材料性能的影响

研究白炭黑/炭黑填充星形溶聚丁苯橡胶(SSBR)和分子链自由末端用硅氧烷基团封端改性星形SSBR(S-SSBR)的物理性能、动态力学性能和微观结构。结果表明:随着偶联剂用量(硅氧烷基团物质的量)的增大,星形SSBR复合材料的拉伸强度先增大后减小,S-SSBR复合材料的拉伸强度先减小后增大;星形SSBR和S-SSBR复合材料的300%定伸应力呈增大趋势,压缩疲劳温升降低,0℃下损耗因子(tanδ)增大,60℃下tanδ值减小。当复合材料中硅氧烷基团的物质的量相同时,与星形SSBR复合材料相比,S-SSBR复合材料定伸应力和0℃下tanδ值的增幅、压缩疲劳温升和60℃下tanδ值的降幅较大,填料的分散性较好。