气相白炭黑的比表面积与表面特性对硅橡胶补强效果的影响

探讨了气相白炭黑的比表面积和表面特性对硅橡胶力学性能的影响,同时采用扫描电镜和溶胀法分别研究了不同表面特性白炭黑补强硅橡胶的拉伸断面形貌和交联密度。结果表明：随着疏水性白炭黑比表面积的增加,硅橡胶拉伸强度和断裂伸长率增加;对比发现,疏水性白炭黑的补强效果优于亲水性白炭黑,这是由于疏水性白炭黑在橡胶基体中分散更加均匀,而且疏水性白炭黑补强硅橡胶的交联密度更大。     

纳米氧化锌对橡胶性能的影响研究

研究了纳米氧化锌对胶料物理性能的影响。纳米氧化锌因其粒径小,表面积大,吸附活性大,从而具有表面效应和高活性;采用纳米氧化锌可提高胶料的耐磨性,H抽出力和撕裂性能,同时纳米氧化锌可以与橡胶分子实现分子水平上的结合,即纳米材料与橡胶分子的接枝作用,达到提高胶料性能的目的。     

超细改性矿物粉体增强硅橡胶

采用材料物理化学和复合材料的方法,系统地研究了８种矿物及其超细粉体和改性粉体与硅本的相互作用。结果表明,湍石、石英和硅灰石对硅橡胶基体具有较好的增强作用。粒径小、比面积大、长径比大等粉体性质好的填料,其增强性能高。界面粘附功与界面张力比值大的复合材料的力学性能好。具有表面活性基团（通过表面改性）、表面缺陷和一的表面羟基是提高粉体增强性能的重要因素。复合粉体的增强性能与粉休性质、混炼胶中的结合橡胶、     

A molecular explanation for the origin of bound rubber in carbon black filled rubber compounds

Some of the theories that have been developed to explain the origin of bound rubber are critically reviewed and discussed with respect to published data. Theories for carbon black filled compounds and for silica–silicone rubber mixtures are considered; the phenomena involved are likely to be very different, with clear chemical aspects for the latter systems. A common feature emerges, however, from these theories: the area of the polymer–filler interaction site, which is generally considered as a fitting parameter in most approaches. This article concentrates on this aspect and suggests that, with respect to recent findings about the very surface of carbon black particles, an explanation for bound rubber can be offered that considers strong topological constraints exerted by the filler surface on rubber segments. Calculations of interaction site area made with experimental data give values close to a fraction of the half-lateral surface of the structural unit representative of the rubber considered. It follows that the bound rubber variation during storage can now be understood by considering a slow replacement of short rubber chains initially adsorbed on filler particles by larger ones, as demonstrated by calculated data. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2257–2268, 1997     

天然橡胶/纳米氧化锌复合材料研究进展

综述了纳米氧化锌制备、改性方法对NR性能的影响,以及纳米氧化锌复合材料的应用研究情况。纳米氧化锌粒径小,比表面积大,具有表面效应和高活性。改性的纳米氧化锌可以在天然橡胶中实现良好分散,可达到提高胶料性能目的,同时降低了ZnO的用量。应用于汽车轮胎、减震器、橡胶止水带,效果显著,符合当今环保发展的趋势。     

Influence of modified natural rubber and structure of carbon black on properties of natural rubber compounds

Carbon black‐filled natural rubber composites were prepared using various types of natural rubber: unmodified natural rubber, epoxidized natural rubber with two levels of epoxy groups at 25 and 50 mol % [epoxidized natural rubber (ENR)‐25 and ENR‐50], and maleated natural rubber. Two types of carbon black (HAF and ECF) with different structure and surface area were used. The functional groups present in natural rubber and carbon black were characterized by FTIR and ¹H‐NMR. Furthermore, cure characteristics, mechanical, morphological, and electrical properties of composites and gum rubber compounds were investigated. It was found that the presence of polar functional groups in rubber molecules and the different structures of carbon black significantly affected the cure characteristics and mechanical properties. This is attributed to physical and chemical interactions between carbon black surfaces and rubber molecules. It was also found that natural rubber filled with ECF showed the highest Young's modulus and hardness, which is due to the high‐surface area and structure of the ECF causing an increase in the degree of entanglement between rubber chains and carbon black particles. Frequency dependency of the dielectric constant, loss tangent, and AC conductivity was also investigated. An increase in dielectric constant, loss tangent, and AC conductivity was observed in the ENR/ECF composites. High‐carbon black loading level caused network formation of these conductive particles, increasing the AC conductivity of the composites. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers     

Self-healing natural rubber based on dynamic disulphide exchange towards fatigue lifetime extension

Dynamic disulphide exchange mechanism was introduced to promote self-healing characteristics to natural rubber compound and the corresponding healing mechanism and mechanical properties are presented. The formation of reversible dynamic disulphide bonds within rubber molecular chains was evidenced via FTIR and the total crosslink density of dynamic disulphide crosslinks was quantitatively measured by equilibrium swelling test. Scanning Electron Microscopy (SEM) results revealed that the healed area of the fractured surface adhered well with minor scar on the contact surface, suggesting that intermolecular diffusion occur at the fracture surface. It was also found that the tensile strength and tear strength of the broken samples able to recover 91% and 103%, respectively, under thermal healing at 150°C for 10 min. The fatigue lifespan of the materials increased 154.9% compared with the conventional rubber. The successful fabrication of self-healing natural rubber through dynamically reversible disulphide exchange mechanism would be expected to open up new opportunities for development of sustainable rubber products.     

纳米SiO2对甲基乙烯基硅橡胶结构和性能的影响

采用沉淀法和气相法纳米SiO2补强硅橡胶,考察纳米SiO2的添加量和比表面积对结合橡胶量、橡胶吸附层厚度以及硅橡胶补强力学性能的影响．通过溶胀平衡实验计算填料补强能力参数C值,并通过扫描电镜观察填料纳米SiO2在硅橡胶中的分散状态．结果表明：填料添加量对硅橡胶力学性能的影响效果显著,当质量比为0．4时,补强橡胶具有较好的力学综合性能,结合橡胶量增大至49．24％,吸附层厚度增至6．87nm,对于气相法纳米SiO2,增大填料比表面积有利于提高结合橡胶量,改善填料的补强效果,补强硅橡胶热稳定性也相应提高,此外填料的C值也随之增大,选一步验证了填料的补强效果增强．     

硅橡胶圆柱表面与光滑表面接触特性研究

采用理论分析与试验研究相结合的方式研究硅橡胶圆柱件与光滑表面的接触特性,重点分析压缩过程中接触压力和接触面积的变化规律。基于Hertz理论,得到接触压力和接触面积的表达式;采用橡胶力学特性测试平台对硅橡胶圆柱件进行压缩试验,得到实际接触面积和接触压力。结果表明,接触面积和接触压力均随压缩量的增大而增大;相同压缩量下,材料的弹性模量对接触面积几乎没有影响,而接触压力与弹性模量呈正相关。理论分析与试验结果具有很好的一致性。     

食品接触材料、高分子材料、橡胶制品中提出物的测定条件的探讨

根据接触的食品类型,选择合适的溶剂,在回流温度下初回流提取7h后,再次回流提取2h,提取液经蒸发、干燥和恒重,得到的残渣的质量,除以试样的表面积,即为提取物的含量。     

Comparison of rubber reinforcement using various surface-modified precipitated silicas

The reinforcement of a natural rubber compound by various surface-modified precipitated silicas was compared. Compound physical properties were determined for two silicas differing in surface area and were used as controls to evaluate these silicas after surface modification by using either a bifunctional organosilane coupling agent (γ-mercaptopropyl–trimethoxysilane) or a new surface modification process. This new process is based on the in situ polymerization of organic monomers solubilized inside surfactant bilayers that are adsorbed onto the silica surface to afford silicas modified with styrene–butadiene and styrene–isoprene copolymers. Both surface modification processes afford materials that dramatically increase the compound cure rate, thereby significantly reducing T₉₀ cure times, while also improving tensile properties, tear strength, abrasion resistance, and compression set of the cured compound. The silane-modified silica gives a higher flex-cracking resistance than do the silicas modified by the in situ polymerization of organic monomers, whereas these latter silicas significantly increase rebound resilience and offer greater overall improvements in rubber compound performance. The rubber compound physical properties obtained using the modified, higher surface area Hi-Sil® 255 silica are generally improved relative to those obtained using the modified Hi-Sil® 233 silica. © 1996 John Wiley & Sons, Inc.     

Studies on Interfacial Characteristics of Highly Dispersible Silica Reinforced Epoxidized Natural Rubber Compounds

The present work examines the effect of two different specific surface areas of highly dispersible silica (HDS)-reinforced epoxidized natural rubber (ENR) composites. The influences of different blend ratio between ENRs consisting 25 and 50?mol% of epoxidation-based (ENR-25/ENR-50) composites was studied in detail. The primary objective is to investigate the interfacial area of HDS surface involved in filler-to-rubber interaction mechanisms for the better reinforcement. Notable improvement in overall properties of these green composites are corroborated with various meticulous characterization including cure characteristics, specific bound rubber content, physicomechanical, dynamic mechanical properties, etc. Increasing the specific surface area of HDS and their subsequent interface with ENR matrix invokes its superior dispersion. Small angle X-ray scattering (SAXS) has been used to analyze the particles network and clusters establishment in green composites. The present SAXS method provides a unique insight into the cluster formation according to the Beaucage model. However, SAXS results demonstrate that particles networks can be effectively suppressed by increasing specific surface area of HDS.     

硅油和白炭黑比表面积对硅橡胶性能的影响

气相法白炭黑是硅橡胶补强的最佳填料,羟基硅油是硅橡胶补强中常用的1种结构控制剂。本文研究了羟基硅油的用量以及气相法白炭黑比表面积对硅橡胶力学性能的影响。结果表明:随着羟基硅油用量的增加,硅橡胶的硬度、拉伸强度均逐渐降低,而断裂伸长率却随羟基硅油用量的增加而逐渐增大;随着气相法白炭黑比表面积的增大,硅橡胶的硬度、拉伸强度逐渐增大,而断裂伸长率逐渐减小。     

Effect of temperature on the extent of migration of low molecular weight moieties to rubber surface

Vulcanized rubbers contain different low molecular weight additives in their formulation, including antiozonants, plasticizers, oils, etc. These moieties - mostly paraffin wax - often migrate to the surface causing a weak boundary layer of non-rubber contaminants which is deleterious for adhesion of rubber to adhesives (such as polyurethane and polychloroprene adhesives). One of the key steps in the manufacturing of rubber/adhesive joints is the reactivation, i.e. sudden heating of the thin adhesive layers on the substrates to be joined under infrared (IR) radiation to 80-90 °C for a few seconds to allow diffusion of the polymeric chains under pressure. This reactivation may cause the migration of low molecular weight additives to the rubber surface causing a lack of adhesion. The main aim of this study was to .identify the influence of the reactivation temperature (40 to 170 °C) on the surface properties of sulphur vulcanized styrene-butadiene rubber and determine the extent of the diffusion of paraffin wax and zinc stearate to the rubber surface. The changes produced on the rubber surface were measured immediately after reactivation treatment by ethylene glycol contact angle measurements, attenuated total reflectance infrared spectroscopy (ATR-IR) and scanning electron microscopy (SEM). Additionally, the weight loss of the rubber after reactivation at different temperatures was recorded.The reactivation of the rubber at different temperatures produced changes in the morphology and thickness of the paraffin wax layer on the surface. By heating at temperature close to that of the paraffin wax melting point, the paraffin wax migration was favoured and at the same time the crystals of paraffin wax on the rubber surface were melted. As a consequence a thicker and smoother film of melting paraffin wax was formed. By increasing the reactivation temperature, a partial removal of paraffin wax was produced and the thickness of the paraffin wax film on the rubber surface was reduced. For reactivation temperatures below 90 °C, the higher the temperature, the lower the weight loss of the rubber, because the increase in the surface area of the melted paraffin wax layer that prevented migration from the rubber bulk. However, for reactivation temperature higher than 90 °C, the weight loss of the rubber increased with the reactivation temperature and this was likely due to sublimation of the paraffin wax on the rubber surface. Besides, even after reactivation at 170 °C, a thin film of paraffin wax always remained on the rubber surface as was evidenced by contact angle measurements. On the other hand, a critical reactivation temperature at 90-100 °C existed at which the migration of zinc stearate to the paraffin wax layer on the rubber surface was favoured.     

空气等离子体处理芳纶纤维及其与天然橡胶/乳聚丁苯橡胶的黏合性能

考察了空气等离子体处理对芳纶纤维表面结构形态的影响,研究了空气等离子体和间苯二酚-甲醛-胶乳(RFL)浸胶处理芳纶纤维与天然橡胶(NR)/乳聚丁苯橡胶(ESBR)的黏合性能,并对经处理的芳纶纤维与NR/ESBR体系的界面层作了动态力学分析。结果表明,芳纶纤维经空气等离子体处理后,表面粗糙度增大,表面积增加,结晶度减小,但处理功率过大、处理时间过长时,芳纶纤维的表面又变得比较光滑、结晶度又呈增大趋势。随着等离子体处理时间的延长,芳纶纤维与NR/ESBR的黏合性能增强,但处理时间过长时,芳纶纤维与NR/ESBR的黏合性能下降;等离子体处理芳纶纤维经RFL进一步浸胶处理后,芳纶纤维与NR/ESBR的黏合性能大幅度提高。芳纶纤维与NR/ESBR的界面存在介于高模量芳纶纤维和低模量橡胶之间的过渡层。     

Properties of natural rubber filled with untreated and treated spent coffee grounds

This work studied the properties of spent coffee ground (SCG) filled natural rubber (NR). The SCG was initially characterized by various techniques, prior to being added into rubber. Results revealed that SCG had relatively large particle size with very low specific surface area. It is mainly composed of organic compounds (such as protein, fatty acid, cellulose, hemicellulose, and lignin) with small quantity of inorganic substances (oxides of potassium, silicon, magnesium, calcium, and phosphorous). The incorporation of SCG in NR gave relatively low reinforcement and tended to retard vulcanization due to the presence of hydroxyl groups on the SCG surface. In addition to untreated SCG, reinforcement of SCG treated by liquid epoxidized natural rubber (LENR) and bis ‐ ( 3‐ triethoxysilylpropyl) tetrasulfide (TESPT) was investigated. Improvement of rubber properties was observed when SCG surface was treated. Overall, TESPT‐treated SCG gave the rubber with the highest mechanical properties, followed by LENR‐treated SCG and untreated SCG, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46060.     

Catalytic characteristics of specialty carbon blacks in decomposition of methane for hydrogen production

Catalytic characteristics of specialty (color and conductive) carbon blacks (CBs) for methane decomposition were investigated and compared with those of rubber blacks. The catalytic characteristics of the color blacks were more similar to those of the rubber blacks, in such that both blacks exhibited very stable activity, a positive correlation of the activity with increasing specific surface area, and higher activation energies. However, the conductive blacks showed quasi-stable behavior, leveling-off of the activity at a somewhat higher value despite their specific surface areas being several times higher than the most active color black, and significantly lower activation energies. These differences were attributed to their morphology differences: the color and rubber blacks were nonporous, whereas the conductive blacks were highly porous. Particularly, the conductive blacks had many dented corners at the pore wall with a highly active armchair structure, resulting in the lower activation energies. Meanwhile, the reaction orders over all the specialty and rubber blacks lay between ca. 0.7 and 1, but no obvious trend in the reaction order was discernible with respect to the surface area or type of CBs.     

Effect of surface‐modified zinc oxide as cure activator on the properties of a rubber compound based on NR/SBR

Zinc oxide (ZnO) and nano‐zinc oxide (nZnO) were surface modified by polyethylene glycol (PEG) and poly propylene glycol (PPG). Modification of particles were controlled by transmission electron microscopy, Brunauer, Emmett, Teller specific surface area measurement, infrared (IR) spectroscopy, and differential scanning calorimetry. IR spectra were shown that the interactions between surface modifiers and particles are hydrogen bonding. Modified particles were applied as an activator in vulcanization of natural rubber/styrene butadiene rubber (NR/SBR) blend. Dispersion of modified particles in rubber matrix was investigated by scanning electron microscopy and shown good results. Blend properties were improved by using modified particles. These improvements were due to the better hydrophobicity of modified particles, which were more compatible with nonpolar rubber matrix and caused better participation in curing process. Modification by PEG and PPG were shown better compound properties for ZnO and nZnO, respectively. Application of ZnO‐modified particles were presented better compound properties in comparison with nZnO‐modified particles. It has confirmed more effective mixing of ZnO‐modified particles in rubber matrix by using ordinary mixers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

橡胶的摩擦性能对其加工的影响

介绍了橡胶加工中研究生胶与金属表面摩擦性能的意义和进展。由微观和唯象分析建立了橡胶粘附摩擦的理论模型。通过对模型的分析和实验验证,提出了提高加工设备生产能力的新途径：(1)密炼机、挤出机、压延机温度控制采用温水冷却，使其处于最佳工作状态；(2)通过合理选择设备材料，改变材料表面能来增大胶料与它们之间的摩擦力；(3)在压力较大的条件下，在密炼室或机简内壁与轴线同方向加工浅的光滑槽可明显改善加工性能。     

Comparative characterization of selected additives by high resolution thermogravimetry and nitrogen adsorption

Silicas and carbon blacks are often used as additives in the production of rubber, plastics, paint, ink, etc. Physicochemical properties of the materials depend not only on the properties of principal component, its chemical nature, degree of cross-linking, polarity, but also on the structural and surface properties of additives (fillers), i.e., their surface area, porous structure, hydrophobicity, etc. In the present work selected additives have been characterized by low temperature adsorption and high-resolution thermogravimetry (TGA). Nitrogen adsorption isotherms measured over a wide pressure range were used to evaluate the specific surface area and total pore volume. In addition, the pore volume and adsorption energy distributions were evaluated from the adsorption data in order to characterize the surface and structural properties of the samples studied.High-resolution TGA has been used to study the weight-loss as a function of temperature for both samples immersed in organic liquids such as n-butanol and n-heptane, and those exposed to their vapors. The characteristic features of the weight-loss curves were analyzed in order to assess the total porosity and the specific surface area of the additives studied as well as to obtain additional information about microstructural and surface heterogeneities of these samples. Thermogravimetric values of the total porosity and the specific surface area were compared with those obtained by nitrogen adsorption measurements for selected rubber additives.