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A wet mixing process is proposed for filled rubber composites with a high silica loading to overcome the drawbacks of high energy consumption and workplace contamination of the conventional dry mixing process. Ball milling was adopted for preparing the silica dispersion because it has a simple structure, is easy to operate, and is a low-cost process that can be easily scaled up for industrial production. The response surface methodology was used to optimize the making of the silica dispersion. The optimum conditions for a well-dispersed silica suspension with the smallest silica particle size of 4.9 mm were an about 22% silica content and 62 h of ball milling. The effects of dry and wet mixing methods on the properties of silica-filled rubber composites were investigated in a broad range of silica levels from low to high loadings. The mixing method choice had little impact on the properties of rubber composites with low silica loadings. The silica-filled rubber demonstrated in this study, however, shows superior characteristics over the rubber composite prepared with conventional dry mixing, particularly with high silica loadings. When compared to silica-filled natural rubbers prepared by dry mixing (dry silica rubber, DSR), the wet mixing (for WSR) produced smaller silica aggregates with better dispersion. Due to the shorter heat history, the WSR exhibits superior curing characteristics such as a longer scorch time (2.2–3.3 min for WSR and 1.0–2.1 min for DSR) and curing time (4.1–4.5 min for WSR and 2.2–3.1 min for DSR). Additionally, the WSR has superior mechanical properties (hardness, modulus, tensile strength, and especially the elongation at break (420–680% for WSR and 360–620% DSR)) over the DSR. The rolling resistance of WSR is lower than that of DSR. However, the reversed trend on the wet skid resistance is observed.

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An attempt was made to generate gasoline-range aromatics from pyrolysis oil derived from rubberwood. Catalytic cracking of the pyrolysis oil was conducted using an HZSM-5 catalyst in a dual reactor. The effects of reaction temperature, catalyst weight, and nitrogen flow rate were investigated to determine the yield of organic liquid product (OLP) and the percentage of gasoline aromatics in the OLP. The results showed that the maximum OLP yield was about 13.6 wt%, which was achieved at 511 C, a catalyst weight of 3.2 g, and an N2 flow rate of 3 mL/min. The maximum percentage of gasoline aromatics was about 27 wt%, which was obtained at 595 C, a catalyst weight of 5 g, and an N2 flow rate of 3 mL/min. Although the yield of gasoline aromatics was low, the expected components were detected in the OLP, including benzene, toluene, ethyl benzene, and xylenes (BTEX). These findings demonstrated that green gasoline aromatics can be produced from rubberwood pyrolysis oil via zeolite cracking. University, Had Yai, Songkhla, 90112, Thailand; * Corresponding author: sukritthira.b@psu.ac.th Keywords: Pyrolysis oil; Zeolite cracking; Organic liquid product (OLP); Green gasoline-range aromatics Contact information: Department of Chemical Engineering, Faculty of Engineering, Prince of Songkla INTRODUCTIONBiomass represents a potential alternative source of energy, which is an important complement to fossil fuels. As such, it attracted significant attention as a renewable source of energy after the global oil crisis of the 1970s (Demirbas 2007;Lucia 2008;Demirbas et al. 2009). In addition, biomass currently is considered to be the only sustainable source that can be used to produce energy-related products, including electricity, heat, and valuable chemicals such as resins, flavorings, and other materials (Huber et al. 2006;Dodds and Gross 2007).The first generation of biofuels were primarily bioethanol and biodiesel made from sugar, starch, and vegetable oil. To date, such biofuels have been widely produced across several countries and continents, notably Brazil, South America, Europe, and the United States (Charles et al. 2007;Mojoviä et al. 2009); however, they have been produced from food-grade biomass, which could lead to critical concerns related to food security (Gronowska et al. 2009). Therefore, it is very important to be able to produce biofuels from non-food resources such as ligno-cellulosic materials: wood chips, switch grasses and most importantly agricultural wastes, such as sugarcane bagasse, corn stover and rice straw.Pyrolysis oils derived from wood-based biomass are one of the most promising renewable fuels. They are environmentally-friendly candidates because they contain a low content of sulfur compared to fossil-derived oils (Czernik and Bridgwater 2004). Recently, extensive attention has been focused on the technology of fast pyrolysis rather than slow pyrolysis, as the former produces high yield of pyrolysis oil with low water content in a PEER-REVIEWED ARTICLE bioresources.com Saad et al. (2015). "Cr...

Rubberwood flour (RWF) was treated by alkaline, silane, and alkaline–silane, and consequently, reinforced recycled polypropylene (rPP) composites. The wood–plastic composites (WPCs) were prepared with 40 wt% RWF content using a twin-screw extruder, followed by compression molding. Silane treatment was applied at various concentrations and treatment times to evaluate the effect of treatment conditions on water absorption, mechanical properties, thermal properties, and morphological characterization of WPCs. The results indicated that alkaline–silane treatment of RWF exhibits higher properties in comparison to silane or alkaline only. In addition, silane concentrations significantly affected water absorption, mechanical strength, and hardness, while treatment times remained relatively unaffected by these properties. The best water resistance, mechanical strength, and hardness of WPCs were achieved by alkaline–silane treatment with 5% silane concentration for 2 h, which improved the interfacial adhesion of RWF and rPP as well as increased the crystallinity in the WPCs.