Multiple Intermolecular Interaction to Improve the Abrasion Resistance and Wet Skid Resistance of Eucommia Ulmoides Gum/Styrene Butadiene Rubber Composite

A rubber composite was prepared by using methyltriethoxysilane (MTES) to modify silica (SiO2) and epoxidized eucommia ulmoides gum (EEUG) as rubber additives to endow silica with excellent dispersion and interfacial compatibility under the action of processing shear. The results showed that compared with the unmodified silica-reinforced rubber composite (SiO2/EUG/SBR), the bound rubber content of MTES-SiO2/EEUG/EUG/SBR was increased by 184%, and its tensile strength, modulus at 100% strain, modulus at 300% strain, and tear strength increased by 42.1%, 88.5%, 130.8%, and 39.9%, respectively. The Akron abrasion volume of the MTES-SiO2/EEUG/EUG/SBR composite decreased by 50.9%, and the wet friction coefficient increased by 43.2%. The wear resistance and wet skid resistance of the rubber composite were significantly improved.

Dodecanol and KH-592 Co-Modify Silica to Prepare Low Heat Build-Up and High Performance Natural Rubber Composites

Friction between filler/filler and filler/matrix in rubber composites is the main factor affecting the heat build-up. In this study, we used dodecanol and silane coupling agent KH-592 to co-modify silica to prepare silica/natural rubber (NR) composites. When dodecanol and KH-592 are grafted onto the surface of silica at the same time, dodecanol can also shield part of the hydroxyl groups by its molecular chain length, which further improves the dispersibility of silica particles. The silane coupling agent KH-592 can form a bridge structure between the silica and the NR matrix under the action of a mercapto group, and improve the interaction between the filler and the matrix. By controlling the use ratio of dodecanol and KH-592, the dispersion of the filler and the interaction between the filler and the matrix can be adjusted. Thereby, the friction between the filler/filler and the filler/matrix is reduced, and a low heat build-up rubber composite material is prepared. Through co-modification, we prepared a series of low-heat build-up silica/NR composites, where the minimum heat generation reached 13∘C. The co-modified silica/NR composite material not only meets the requirements of green tires, but also has low heat build-up characteristics, providing a new strategy for preparing green and energy-saving tires.

Using Epoxidized Solution Polymerized Styrene-Butadiene Rubbers (ESSBRs) as Coupling Agents to Modify Silica without Volatile Organic Compounds

Rubber used in tire is usually strengthened by nanofiller, and the most popular nanofiller for tire tread rubber is nano silica, which can not only strengthen rubber but also lower the tire rolling resistance to reduce fuel consumption. However, silica particles are difficult to disperse in the rubber matrix because of the abundant silicon hydroxyl on their surface. Silane coupling agents are always used to modify silica and improve their dispersion, but a large number of volatile organic compounds (VOCs) are emitted during the manufacturing of the nanosilica/rubber composites because of the condensation reaction between silane coupling agents and silicon hydroxyl on the surface of silica. Those VOCs will do great harm to the environment and the workers’ health. In this work, epoxidized solution polymerized styrene-butadiene rubbers (ESSBR) with different epoxy degrees were prepared and used as macromolecular coupling agents aimed at fully eliminating VOCs. Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) analyses verified that the different ESSBRs were successfully synthesized from solution polymerized styrene-butadiene rubbers (SSBR). With the help of the reaction between epoxy groups and silicon hydroxyl without any VOC emission, nanosilica can be well dispersed in the rubber matrix when SSBR partially replaced by ESSBR which was proved by Payne effect and TEM analysis. Dynamic and static mechanical testing demonstrated that silica/ESSBR/SSBR/BR nanocomposites have better performance and no VOC emission compared with Bis-(γ-triethoxysilylpropyl)-disulfide (TESPD) modified silica/rubber nanocomposites. ESSBR is very hopeful to replace traditional coupling agent TESPD to get high properties silica/rubber nanocomposites with no VOCs emission.

Fundamentals and recent progress relating to the fabrication, functionalization and characterization of mesostructured materials using diverse synthetic methodologies

Since 1990 and the invention of the very first generation of ordered mesoporous silica materials, several innovative methodologies have been applied to synthesize, characterize, and modify silica/non-silica mesoporous materials.

Poly(methyl methacrylate) Grafted Silica Nanoparitcles via ATRP for Bis-GMA/TEGDMA Dental Restorative Composite Resins

To improve the dispersibility of silica nanoparticles in dimethacrylate-based dental restorative composite resins, an efficient way was proposed to surface modify silica nanoparticles with polymer grafts. Firstly, silica nanoparticles reacted with 3-aminopropyl-triethoxysilane and 2-bromoisobutyryl bromide to obtain silica with the derived atom transfer radical polymerization (ATRP) initiators, which subsequently initiated the polymerization of methyl methacrylate to fabricate poly(methyl methacrylate) grafted silica nanohybrids. These nanohybrids could be well dispersed into bisphenol A glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) resin and had good interfacial bonding to the resin matrix. With the addition of modified silica nanopaticles, the flexural strength of the photo-cured composite resin was significantly increased in comparison with that of the unmodified group.