硅酮橡胶填充剂用沉淀法白炭黑

本发明介绍新型的硅酮橡胶填充剂用沉淀法白炭黑。     

橡胶补强填充剂概览

加入各种补强性填料可提高橡胶制品的物理机械性能,延长使用寿命。除了常用的炭黑、白炭黑,该文还介绍了炭黑-白炭黑双相填充剂,以及改性高岭土、凹凸棒改性粘土、改性硬质陶土、纳米氧化锌等其他填充剂,并围绕轮胎技术对各种补强性填料进行了展望。     

白炭黑／硅烷填充胶料的交联与补强

自上世纪七十年代初开发出偶联剂Si-69(双-[三乙氧基甲硅烷基丙基]多硫化物)以来，特别是自从1992年引入绿色轮胎以来，白炭黑／硅烷补强体系就成了橡胶技术中固有的组成部分。除因其滚动阻力降低和湿牵引性显著提高而主要应用于轿车轮胎胎面胶外，白炭黑尚被用于工业橡胶制品当中。此时，胶料展示出高撕裂强度、低滞后损失和低导电性。、     

白炭黑硅烷化改性程度表征方法的研究

研究白炭黑硅烷化改性程度表征方法。结果表明:填料与填料之间的相互作用强烈依赖于应变,小于50%应变下的Payne效应可以很好地表征白炭黑硅烷化改性程度;在相同温度、频率和时间下,应变越小,越能区分出白炭黑的分散性优劣,通过橡胶加工分析仪小应变等温试验得到的弹性模量可以表征白炭黑的硅烷化改性程度;大应变模量与小应变模量比值越大,说明填料网络化作用越小,硅烷化反应越完全,填料分散性越好;门尼粘度、硬度、耐磨性能、损耗因子、动态压缩生热等也可侧面表征白炭黑的硅烷化改性程度。所得性能数据需综合对比和深度分析。     

硅酮橡胶填充剂用新型沉淀法白炭黑

本发明与硅酮橡胶填充剂用新型沉淀法白炭黑有关，具体来说，这种沉淀法白炭黑用作硅酮橡胶的补强填料时，既能保持胶料的高补强特性，又能使胶料具有有利于加工性的硬度。     

白炭黑／硅烷填料体系的化学与橡胶补强性

1 橡胶用沉淀法白炭黑 1．1沉淀法白炭黑的形态 合成白炭黑根据其生产工艺和特性有各种不同的种类，但沉淀法白炭黑在橡胶行业应用最为广泛。沉淀法白炭黑是采用在硅酸钠水溶液中添加酸的分批式沉淀工艺合成的。在这一沉淀工序中形成的是白炭黑一次粒子及其聚集结构，而且通过控制反应时间、温度、pH等参数，其比表面积、结构等白炭黑的主要特性已经在该阶段确定。     

炭黑-白炭黑双相填充剂

介绍了现已开发出来的一种炭黑－白炭黑双相填充剂,使轮胎生产厂商大大降低了台的滚动阻力,提高了牵引力,而且对耐磨耗性能未产生任何不利的影响。报道了对３种ＥＣＯＢＬＡＣＫ的研究结果,指出表面积和白炭黑质量分数对轿车轮胎胎面胶的影响。     

Impact of filler geometry and surface chemistry on the degree of reinforcement and thermal stability of nitrile rubber nanocomposites

The morphological, mechanical, and thermal stability of Nitrile rubber nanocomposites reinforced with fillers such as layered silicate (LS), calcium phosphate (CP) and titanium dioxide (TO) having different particle size and chemical nature were analyzed. The results revealed that the filler geometry played an important role on the mechanical and thermal stability of the composites. Calcium phosphate and titanium dioxide filled systems showed comparatively better mechanical and thermal stability compared to neat rubber. The activation energy needed for the thermal degradation was found to be higher for layered silicate filled system. DSC (Differential Scanning Calorimetry) analysis revealed a change in the T_g values as a result of the addition of fillers. This was more prominent with the case of layered silicate filler addition in comparison with calcium phosphate and titanium dioxide. The heat capacity values of the nanocomposites were carefully evaluated. The (∆Cp) with values obtained for different nanocomposites were correlated with the degree of reinforcement. It can be assumed that more polymer chains are attached on to the surface of the filler and there exists an immobilized layer around the filler surface and the layers do not take part in the relaxation process. The FTIR spectrum of the different samples highlighted the possible filler matrix interaction. The filler dispersion and aggregation in the polymer matrix were analyzed using X-ray diffraction studies (XRD), transmission electron microscopy (TEM), and atomic force microscopy (AFM).     

Some simulations on filler reinforcement in elastomers

This review illustrates how elastomer reinforcement can be modeled using Monte Carlo simulations on rotational isomeric state chains to characterize their spatial configurations in the vicinity of filler particles. The results are distributions of the chain end-to-end distances as perturbed by this excluded-volume effect, and the results obtained are in agreement with experimental results gotten by neutron scattering. The use of these distributions in standard molecular theories of rubberlike elasticity then produces stress-strain isotherms suitable for comparison with those in elongation experiments. Such simulations have now been carried out for elastomeric matrices reinforced by spherical filler particles (either on a cubic lattice or randomly dispersed), or by prolate or oblate particles on cubic lattices (either with their axes oriented or randomized). The simulated mechanical properties are consistent with experimental results available at the present time, and should provide encouragement and guidance for additional simulations and experiments.     

Isobutylene-based ionomer composites: siliceous filler reinforcement

The morphology, mechanical, and barrier properties of composites derived from phosphonium bromide ionomer derivatives of an isobutylene-based elastomer (IIR-PPh₃Br) are compared with analogous non-ionic composites. Improved adhesion between the ionomer and onium ion-exchanged montmorillonite clay allowed standard polymer compounding techniques to yield highly reinforced elastomer nanocomposites. Similar increases in the strength of interactions between ionomer and precipitated silica resulted in reduced filler agglomeration, and higher degrees of composite reinforcement.     

The relationship between the physico-mechanical properties and the filler concentration in the HD polyethylene-dispersed filler system

The relationship of 10 basic physico-mechanical properties and the concentration of the filler is investigated through narrow filling intervals of seven different composite series containing various types of HD polyethylene and different grades of kaolin. A variety of mixing techniques for the preparation of the composites is used, and testing is carried out by applying different techniques and conditions. The investigations show that, in all cases when an identical mixing technique is applied for a given series of composite formulations, the relationship linking the physico-mechanical and dynamic-mechanical G′, G″, and tan δ properties with the concentration of the filler is not a monotonous curve, and displays a multiextermal character. We propose as one possible explanation that a periodic change in the free volume and the content of crystal polyethylene phase exists, as a function of the filling. The nonmonotonous character of the changes of properties is related to the proposed mechanism for the change of the physical structure of composites, which are composed of filler particles coated with n monolayers of polyethylene crystallites, when, as filling continues, periodically new types of filler particles are formed. The nonmonotonous character of the relationship between the properties and the concentration of the filler should be taken into consideration when these relationships are approximated or expressed in a mathematical-analytical form, especially when high amounts of fillers (more than 20 vol %) are used.     

Synergistic reinforcement of NBR by hybrid filler system including organoclay and nano‐CaCO3

Rubber nanocomposites containing one type of nanofiller are common and are widely established in the research field. In this study, nitrile rubber (NBR) based ternary nanocomposites containing modified silicate (Cloisite 30B) and also nano‐calcium carbonate (nano‐CaCO₃) were prepared using a laboratory internal mixer (simple melt mixing). Effects of the hybrid filler system (filler phase have two kind of fillers) on the cure rheometry, morphology, swelling, and mechanical and dynamic–mechanical properties of the NBR were investigated. Concentration of nano‐CaCO₃ [0, 5, 10, and 15 parts per one hundred parts of rubber by weight (phr)] and organoclay (0, 3, and 6 phr) in NBR was varied. The microstructure and homogeneity of the compounds were confirmed by studying the dispersion of nanoparticles in NBR via X‐ray diffraction and field emission scanning electron microscopy. Based on the results of morphology and mechanical properties, the dual‐filler phase nanocomposites (hybrid nanocomposite) have higher performance in comparison with single‐filler phase nanocomposites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42744.     

Anisotropic reinforcement in elastomers containing magnetic filler particles

Magnetic particles of iron oxide were blended into portions of a high molecular weight sample of poly(dimethylsiloxane) which were then peroxide cured in a magnetic field. Strips cut from the resulting elastomers parallel and perpendicular to the magnetic lines of force were studied with respect to their equilibrium swelling and their stress–strain isotherms in elongation. Both resistance to swelling (as measured by the volume fraction of polymer in the network) and the elongation modulus increased with increase in the amount of filler. They were also generaly larger in the direction parallel to the field, and the differences increased both with increase in the amount of filler and with increase in the strength of the magnetic field. Stress relaxation also increased with amount of filler and field strength, thus illustrating the importance of adsorption of the polymer onto the filler particles, and its subsequent desorption under stress.     

Model filler reinforcement studies by small angle X-ray scattering

Polybutadiene rubbers, filled with polydichlorostyrene or polystyrene latices having spherical diameters of approximately 500Å, were examined by small angle x-ray scattering. The filler latices were examined by x-ray scattering as a function of strain. The sample elongations ranged up to 400 percent. An analysis of the scattering of the polydichlorostyrene filler latices showed that there was deformation of the filler particles up to 25 percent. Such a deformation is not expected on the basis of the mechanical properties of bulk glassy polydichlorostyrene. However, deformation into ellipsoids of revolution is consistent with the x-ray evidence. The deformation of the latices is reasonable.     

Mineral filler reinforcement for commingled recycled‐plastic materials

Three types of mineral fillers, gypsum, wollastonite, and talc, were investigated for their ability to modify the mechanical properties of commingled recycled‐plastic composites containing 0.07–0.26 v/v of filler. Mechanical test results showed that the talc reinforced composites were significantly better in mechanical properties when compared with the gypsum and wollastonite composites. Scanning electron microscopy (SEM) showed that gypsum formed large agglomerates in the matrix. Interfacial adhesion between filler and matrix was evaluated using simple empirical models. To enhance the adhesion, talc, and wollastonite were pretreated with silane coupling agents, 3‐methacryloxypropyltrimethoxy silane (γ‐MPS) and 3‐aminopropyltriethoxy silane (γ‐APS). This did not result in any significant improvement to the material properties. The γ‐APS treatment, however, increased the tensile properties of the composites by ～ 5% when compared with the γ‐MPS treatment. The SEM investigations showed that the γ‐APS treatment provided better adhesion of filler particles and hence voids were less likely to form in the matrix when compared with the γ‐MPS composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A simple theory of filler reinforcement in elastomers subjected to shear

The effects of a filler in an elastomer can be described by means of a theory based on a simple model in which the filler particles are assumed to be of uniform size, of cubic shape, and dispersed in such a manner as to occupy the points of a cubic space lattice. For the case of shear deformation, simple relations can be derived for the increase in the storage modulus G' and the loss modulus, G″ of the bulk material with an increase in filler content. Furthermore, the theory predicts the temperature shift of two points which can be easily determined experimentally: the inflection point of G' and the maximum of G″.     

Multiscale characterization of filler dispersion and origins of mechanical reinforcement in model nanocomposites

We report on the influence of parameters controlling filler dispersion and mechanical reinforcement in model nanocomposites. We elaborate a series of nanocomposites and present a structural characterization of silica dispersion in polymer matrix for several particle sizes and polymer matrices, at all relevant scales, by coupling Small Angle X-ray Scattering and Transmission Electronic Microscopy. The mechanical properties are investigated in the linear regime by coupling Dynamical Mechanical Analysis and plate/plate rheology. The results show that: (i) for all filler sizes and matrices, a structural transition is observed from non-connected fractal aggregates at low silica concentration to connected network at high particle content. (ii) In the dilute regime, the reinforcement implies a polymer chain contribution with different possible origins: increase of entanglements density for PS and increase of friction coefficient for PMMA. (iii) In the concentrated regime, for a given polymer, the reinforcement amplitude can be tuned by the rigidity of the filler network, which directly depends on the particle–particle interaction.