Rubber blends are widely used for combining the advantages of individual rubber component. However, to date, how to determine and distinguish the vulcanization kinetics for each single rubber phase in rubber blends during the co-vulcanization process are still a challenge. Herein, high resolution pyrolysis gas chromatography-mass spectrometry (PyGC-MS) was employed for the first time to investigate the vulcanization kinetics of natural rubber (NR) and styrene-butadiene rubber (SBR) in their blends filled with graphene. It is shown that the crosslinking rate of NR chains (k(NR)) was much lower than that of SBR chains (k(SBR)) in the unfilled blends and blends with untreated graphene. Interestingly, the gap between k(SBR) and k(NR) was narrowed effectively in the blends with vulcanization accelerator grafted graphene, showing a better co-vulcanization of NR and SBR. In addition, the vulcanization accelerator grafted graphene was uniformly dispersed in rubber matrix and endowed rubber blends with higher mechanical strength and thermal conductivity did the untreated graphene.

Rubber blends are widely used for combining the advantages of each rubber component. However, to date, how to determine and distinguish the vulcanization kinetics for each single rubber phase in rubber blends during the co-vulcanization process is still a challenge. Herein, high-resolution pyrolysis gas chromatography–mass spectrometry (HR PyGC-MS) was employed for the first time to investigate the vulcanization kinetics of natural rubber (NR) and styrene–butadiene rubber (SBR) in NR/SBR blends filled with modified silica (SiO2). The reaction rates of crosslinking of each rubber phase in NR/SBR were calculated, which showed that the crosslinking rates of NR were much lower than those of SBR phase in the unfilled blends and blends filled with unmodified and silane modified silica. Interestingly, the vulcanization rates of NR and SBR phase were approximately same in the vulcanization accelerator modified silica filled blends, showing better co-vulcanization. In addition, the vulcanization accelerator modified silica was uniformly dispersed and endowed rubber blends with higher mechanical strength compared to the untreated silica. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48838. © 2019 Wiley Periodicals, Inc.

A novel rare-earth complex containing hindered phenol and thioether groups (Sm-GMMP) was prepared by using 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylphenyl) methyl-4-methylp-henyl acrylate (GM), 3-mercaptopropionic acid (MPA) and samarium chloride hexahydrate (SmCl3 center dot 6H(2)O) via Michael addition reaction of sulfydryl with acrylate and coordination reaction. The chemical structure of Sm-GMMP was confirmed by H-1-NMR, FT-IR, XPS and elemental analysis. It was revealed by the results of the accelerated thermal aging tests, FTIR-ATR, TGA, whiteness and yellowness index that Sm-GMMP significantly improved the thermo-oxidative aging resistance and thermal-oxidative stability of styrene-butadiene rubber/silica composites without discoloration. The outstanding antioxidative ability of Sm-GMMP for SBR/silica composites was attributed to not only the synergistic antioxidative effect between hindered phenol and thioether groups, but also the deactivation role of samarium ions to oxygen free radicals and its excellent thermal stability. (C) 2019 Elsevier Ltd. All rights reserved.

It is well known that the coupling reagents as the additional modifiers were often used to improve the reinforcement effect of silica filled natural rubber. Actually, the commercial raw NR is a mixture consisting of polyisoprene and non-isoprene, where the latter one might have impact on the properties of NR/silica composites as an inartificial modifier inside. Thus, investigating the effect of non-isoprene compounds on the structure and properties of NR/silica composites is a novel approach to disclose the peculiarity of NR, which is meaningful to the assessment of NR quality. In this paper, the influences of acetone extract (AE) from natural rubber on the structure and mechanical properties of NR/silica composites were studied. Then the interfacial interactions between AE and silica were also illustrated through Fourier transform infrared spectroscopy (FTIR), thermogravimetic analysis (TGA), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Results demonstrated the existence of hydrogen bond between silica and AE, also the covalent bond induced by esterification reaction between-COOH and Si-OH, which resulted in an increase of constrained regions around silica surface leading to the promotions on mechanical and dynamical properties of NR/silica composites significantly. (C) 2017 Elsevier B.V. All rights reserved.

发展低滚阻、抗湿滑、高耐磨、高寿命的高性能轮胎，对广东和全国橡胶产业的自主创新和产业结构调整至关重要。橡胶基纳米复合材料因在轮胎工业中的潜在应用前景，正成为研究热点。本项目结合高性能轮胎的要求，主要针对橡胶基纳米复合材料的制备技术、界面结构、网络结构、动态性能等研究中的关键科学问题，系统深入地开展新型纳米材料在橡胶基纳米复合材料中的应用、原位反应法制备橡胶基纳米复合材料、新型多功能改性剂的制备及其对纳米复合材料结构和性能的影响、橡胶基纳米复合材料的网络互穿增强新方法、橡胶基纳米复合材料的结构形态与动态性能的关系等基础研究，重点研究了埃洛石纳米管、石墨烯、纳米微晶纤维素、纳米木质素、白炭黑等新型纳米材料的制备及表面改性技术，以及采用原位反应法制备高性能轮胎用橡胶基纳米复合材料。研究发现，通过表面改性，加强纳米材料与橡胶基体的界面结合，不仅有效提高纳米材料在基体中的分散，实现补强，同时还明显降低复合材料的生热性能，提高动态性能。多功能改性剂的合成及应用研究发现，它们不仅可与橡胶分子链接枝，还能与纳米填料形成氢键、共价键或配位键，能促进橡胶硫化，改善填料分散，同时能够赋予复合材料更好的抗湿滑性和较低的滚动阻力，改进耐磨和压缩疲劳性能。此外，加入某些能与纳米填料表面形成氢键或化学键的多官能度反应性改性剂，通过自组装构筑填料网络，与橡胶交联网络实现网络互穿，对复合材料产生特殊的增强和改性效果。这种网络互穿增强的新方法不同于传统的炭黑增强和通常的无机纳米粒子增强的概念，能产生更好的增强效果。将以上研究成果应用到轮胎胎面胶中，研究发现，不仅可以提高橡胶复合材料的力学性能，还能实现在动态性能上60 °C时的tan δ下降27.2%;同时0 °C时的tan δ升高19.3%,即实现了同时降低滚动阻力和提高抗湿滑性能，且复合材料具有更好的耐磨性能和更低的压缩疲劳生热性能。在此基础上，本项目的研究成果在广州华南橡胶轮胎有限公司进行了中试研究。试制的高性能轮胎，其耐久性和高速性能等综合性能也达到有关国家标准；轮胎滚动阻力下降了25%,滚动系数降至7.51,滚动阻力标签等级为B级。本项目的研究为橡胶基纳米复合材料在高性能轮胎和其他高性能橡胶制品中的应用提供了很好的理论指导和产业化基础。 Rubber composites have been attracted extensive attention due to their potential application in the tire industry.Aiming to meet the requirement of high performance tire,this work focused on the preparation technology,interface structure,network structure and dynamic performance of rubber composites.We deeply studied the application of the new nanometer materials in the rubber composites,in situ reaction for preparing rubber composites,the preparation of novel multi-functional modifier and its influence on the structure and performance of composites,the novel“interpenetrating network”enhancement approach towards rubber composites,and the relationship between the structure and dynamic performance of rubber composites,etc.Therefore,we focused on the preparation of new nanomaterials and surface modification technology of halloysite nanotubes,graphene,microcrystalline cellulose,lignin,silica,etc,and the preparation of high performance tire rubber nanocomposites using in situ reaction.The study found that the surface modification is in favour of enhancing the interfacial adhesion between the nano-materials and rubber matrix,result of which not only effectively improve the dispersion state of nano-materials in the matrix,also significantly reduce the heat production and improve the dynamic performance.The research about the synthesis and application of multi-function modifier indicated that the multi-function modifier can take graft reaction with rubber chains,and efficiently form hydrogen bond,covalent bond or coordination bond,further promoting the vulcanization of rubber and improving the dispersion of filler.Notably,such novel modifier can endow the vulcanized rubber composites with better wet resistance,lower rolling resistance,and wear resistance and compression fatigue performance.Additionally,the incorporation of polyfunctional reactive modifier can facilitate to construct filler network by self-assembly method,realizing the interpenetrating network in the rubber network,and hence producing special enhancement and modified effect towards rubber composites.Due to the above combination,the obtained research findings were applied to the tire tread rubber.The loss factor at 60 °C decreased by 27.2%,whereas the loss factor at 0 °C increased by 19.3%.The prepared tires not only satisfy the performance requirement of meridian tire,also the rolling resistance significantly decreased by 25%,the value of which lowers to 7.51.Noteworthily,the rolling resistance label level is to be class B.

The focus of this study was on the thermo-oxidative aging resistance of a new rare earth complex, samarium lysine dithiocarbamate (Sm-LDC), in the styrene-butadiene rubber (SBR)/silica composites. The anti-aging behavior of SBR/silica composites with Sm-LDC, as well as several common commercial antioxidants, was systematically investigated by oxidation induction time (OIT), mechanical testing, crosslink density determination, Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR), and thermo-gravimetric analysis (TGA). The results demonstrated that Sm-LDC significantly improve the thermo-oxidative stability of SBR/silica composites and protect the composites against the thermo-oxidative aging more effectively than the widely used antioxidant 4010NA and antioxidant MB in rubber industry. It could be attributed to the synergistic effect between dithiocarboxyl groups and samarium ions in Sm-LDC, which can high-efficiently decompose the hydroperoxide and scavenge the oxy radicals, respectively. Besides, the results of whiteness and yellowness index (Y.I) analysis indicated that Sm-LDC can hardly cause discoloration to the SBR/silica composites and is better than the recognized light-colored antioxidant MB in the aspect of color. This research might open up new opportunities for preparing highly thermo-oxidative aging-resistant rubber composites without color contamination. (C) 2016 Elsevier Ltd. All rights reserved.

In this study, a novel rare-earth complex, dithio-aminomethyl-lysine samarium (DALSm), was prepared and then was employed as activator, accelerator, cross -linker and interfacial modifier to improve the mechanical properties of SBR/silica nanocomposites. The results showed that 6 phr DALSm performed a higher vulcanization efficiency than the combination of 5 phr activator zinc oxide (ZnO), 2 phr stearic acid (SA), and 2 phr accelerator diethyl dithiocarbamate zinc (EDCZn). Meanwhile, the XPS and FTIR analysis of DALSm/silica model compounds confirmed that hydrogen bonds and coordination bonds could be formed between DALSm and silica during vulcanization process, which can effectively facilitate the homogenous dispersion of silica particles into SBR matrix and enhance the interface adhesion between rubber matrix and filler. As a consequent, the mechanical properties of SBR/DALSm/silica nanocomposites were substantially improved and much more excellent than those of the SBR/EDCZn/silica nanocomposites containing equivalent filler content. Based on the results of immobilized polymer layer, the reinforcing mechanism of DALSm in SBR/silica nanocomposites was analyzed. (C) 2016 Elsevier Ltd. All rights reserved.

In our work, effects of 2-mercapto-1-methylimidazole modified graphite nanoplatelet (MMI-GN) and carbon black (CB) on static and dynamic mechanical properties of styrene butadiene rubber (SBR) composites were studied. MMI-GN is synthesized by ball-mill process, and the result reveals that pi-pi interactions existed between MMI and GN. The results demonstrate that the static and dynamic mechanical performances of SBR/CB/MMI-GN composites are significantly improved over these of SBR/CB and SBR/CB/GN composites. Compared with SBR/CB, the tensile strength, tear strength, and modulus at 300% elongation of SBR/CB/MMI-GN-3 are greatly improved by 45%, 27%, and 4%, respectively. And the rolling resistance of SBR/CB/MMI-GN-3 is reduced by 3.7% with remaining almost unchanged in the wet grip property. The superiority of MMI-GN in the enhancement for the overall performance of SBR/CB composites is attributed to the well dispersion of GN throughout the SBR matrix and the enhanced interfacial interactions between GN and the SBR matrix. This work might expedite synthesis of the graphite-based materials for enhancing rubber composites, and enlarge the potential applications of modified graphite to fabricate the high-performance rubber composites. Copyright (C) 2016 John Wiley & Sons, Ltd.

In this work, a novel multifunctional rubber agent named as samarium lysine dithiocarbamate (Sm-LDC) was synthesized by a nucleophilic addition reaction and coordination reaction. Then the influences of Sm-LDC on curing properties, and static and dynamic mechanical properties of SBR/SiO2 composites were studied. The results showed that Sm-LDC is not only capable of accelerating the vulcanization of SBR compounds even without zinc oxide (ZnO) and stearic acid (SA), also conducive to improve the crosslinked network. Notably, SBR/Sm-LDC/SiO2 composites exhibit superior static and dynamic mechanical properties in comparison with the SBR/SiO2 composite containing conventional accelerator zinc diethyl dithiocarbamate (ZDC), and activators ZnO and SA. Such improvement is attributable to the improved dispersion of SiO2, the enhanced filler-rubber interaction, and the high vulcanization and reinforcing efficiency of Sm-LDC. Accordingly, the excellent comprehensive performance may make Sm-LDC very competitive in the application in green tires and the preparation of high performance rubber composites.

An effective approach is developed to synthesize zinc dimethacrylate functionalized graphene (ZDMA-GE) as reinforcing nanofiller for natural rubber (NR). The morphology and structure of ZDMA-GE were characterized to confirm the exfoliation and functionalization of GE. The as-prepared nanocomposites were investigated by transmission electron microscopy, mechanical analysis, crosslinked network analysis, and the analysis of thermal conductivity. The results demonstrated that there is strong interfacial interaction between GE and rubber matrix due to good dispersion and special two-dimensional structure of GE. The crosslink density of the nanocomposites is greatly improved with the introduction of ZDMA-GE because of the homopolymerization and graft polymerization of ZDMA. It is also noticed that the tensile strength, tear strength, and modulus at 300% elongation of NR nanocomposites with 15 phr ZDMA-GE have been improved by 133, 42, and 174%, respectively. The thermal conductivity of nanocomposites with 40 phr ZDMA-GE is enhanced 1.3 times as that of the pure NR. This remarkable improvement is attributed to the formation of covalent crosslinked network and ionic crosslinked network, good dispersion of GE, and efficient interfacial interaction between GE and NR matrix. This method provides the potential applications of functionalized GE in the polymer composites. (C) 2014 Society of Plastics Engineers