Please cite this article as: Ramarad, S., Khalid, M., Ratnam, C.T., Luqman Chuah, A., Rashmi, W., Waste tire rubber in polymer blends: A review on the evolution, properties and future, Progress in Materials Science (2015), doi: http://dx. AbstractThis review addresses the progress in waste tire recycling with a particular attention to incorporation of waste tire rubber (WTR) into polymeric matrices. Methods of waste tire downsizing, importance of WTR characterization and current practice of WTR modification has been emphasized. Detailed discussion on influence of WTR size, loading, modification, compatibilization and crosslinking on the rheological, mechanical and thermal properties of rubber, thermoplastic and thermoplastic elastomer blends utilizing WTR has been reported.By far, thermoplastic elastomer blends; though still in its infancy; has shown the most promising properties balance which is capable of commercialization. Rubber/WTR blends 2 also show ease of processing and acceptable properties. Thermoplastic/WTR blends suffers in term of toughness and elongation at break. However, the waste thermoplastic/WTR is a viable solution to address polymeric waste problem. Review also highlights the lack of studies concentrating on dynamic mechanical, aging, thermal and swelling properties of WTR polymeric blends.

This study compares the adsorption capacity of modified CNTs using acid and heat treatment. The CNTs were synthesized from acetone and ethanol as carbon sources, using floating catalyst chemical vapor deposition (FC-CVD) method. energy-dispersive X-ray spectroscopy (EDX) and Boehm method revealed the existence of oxygen functional group on the surface of CNTs. Heat modification increases the adsorption capacity of as-synthesized CNTs for methylene blue (MB) and phenol by approximately 76% and 50%, respectively. However, acid modification decreases the adsorption capacity. The equilibrium adsorption data fitted the Redlich-Peterson isotherm. For the adsorption kinetic study, the experimental data obeyed the pseudo-second-order model. Both modifications methods reduced the surface area and pore volume. The studies show that the adsorption of MB and phenol onto modified CNTs is much more influenced by their surface functional group than their surface area and pore volume.

The effect of irradiation on a 90/10 ethylene vinyl acetate/waste tire dust (EVA/WTD) blend was studied in the presence of 4 phr trimethylolpropane triacrylate (TMPTA) or tripropyleneglycol diacrylate (TPGDA). The blend was irradiated using a 3.0-MeV electron beam machine at 0, 50, 100, 150, and 200 kGy irradiation doses. The properties studied include gel content, tensile properties, hardness, morphology, and dynamic mechanical properties. The result revealed that the increment in irradiation doses will increase the percentage of gel content. The gel content further increased with the introduction of TMPTA and TPGDA. This is attributed to the increase in crosslink density. Tensile properties of EVA/WTD blend increase with the introduction of irradiation except for elongation at break. The tensile-fractured surface of EVA/WTD blends showed ductile type of failure upon irradiation of the blends in the presence of crosslinking agent. One glass transition temperature obtained from dynamic mechanical analysis for 90/10 EVA/WTD blend after irradiation indicates that compatibility between EVA and WTD phases increased.

This work investigated the effects of extraction temperature on the quality of extract and the kinetics of solid‐liquid extraction of betel leaves. In this study, the effects of extraction temperature on the quality of extract were evaluated by comparing the concentration of its active compounds, including hydroxychavicol (HC) and eugenol (EU). The results indicate that the increase of extraction temperature led to the increase of the concentration of HC. EU concentration was decreased when temperatures higher than 60C were used. The kinetics data show that the extraction process reached equilibrium in a short time – about 40 min. Two models, namely equilibrium‐dependent solid‐liquid extraction (EDSLE) model and diffusion‐dependent solid‐liquid extraction model were applied to describe the extraction process. By comparing the values of correlation coefficients, the EDSLE model was found to be more suitable in describing the extraction process as it provided a better fit to the experimental data. PRACTICAL APPLICATIONS Betel leaves is one of the invaluable medicinal plants that has multiple useful bioactivities found in Malaysia. In this work, the effect of extraction temperature on the quality of the extract of betel leaves was investigated by quantifying the change of two active compounds, namely hydroxychavicol and eugenol. This is because the bioactivities depend on the content of the phytochemicals within the plant. The critical extraction temperature was determined based on the findings. Aside from this, the kinetics of the extraction process was also studied. Two mathematical models including equilibrium‐dependent solid‐liquid extraction (EDSLE) model and diffusion‐dependent solid‐liquid extraction model were used to predict the extraction process. EDSLE, which is simple and easy to be solved, was applicable in simulating the extraction process. The findings from this study are useful in understanding and optimizing the solid‐liquid extraction process of betel leaves.

Non-degradable waste tire generation around the world is growing at an alarming rate. Diversifying the recycling route of these waste tires is essential to solve the problem. One way is to incorporate them into polymers and convert them into new products. However, incorporation of ground tire rubber into thermoplastics has been hampered due to lack of toughness and adhesion between phases. To address the issue, this study utilized reclaimed waste tire rubber (RTR) instead; and evaluated the properties of RTR and poly(ethyleneco-vinyl acetate) (EVA) blends. The properties of the RTR/EVA blends were further enhanced by compatibilization and electron beam irradiation.Processing, mechanical, thermal and dynamic mechanical properties of RTR were tremendously improved by blending with EVA. However, the interfacial adhesion was found to lack in the blends. Compatibilization by reactive, physical and combination strategies were explored utilizing (3-Aminopropyl)triethoxy silane (APS), liquid styrene butadiene rubber (LR) and maleated EVA (MAEVA), respectively. APS and MAEVA were found to be the most and least favourable compatibilizer, respectively. Apart from functioning as reactive compatibilizer, APS also reclaimed the RTR phase further. These lead to improved dispersion of smaller RTR phase in EVA matrix and enhanced the interfacial adhesion.Electron beam irradiation revealed the presence of radical stabilizing and scavenging additives within RTR which retards the crosslinking process in RTR and RTR/EVA blends. Though chain scissions were predominant; study showed the replacement of S-S and S-C bonds with stronger and stiffer C-C bonds ensures the retention of RTR and RTR/EVA blends properties upon irradiation.Compatibilization of RTR/EVA blend by APS (50RTR/5APS) also improved the crosslinking efficiency. However, the blend still suffered from oxidative degradation from irradiation in air. Radiation sensitizers, trimethylol propane triacrylate (TMPTA), tripropylene glycol diacrylate (TPGDA) and N,N-1,3Phenylene Bismaleimide (HVA2), were used to accelerate the irradiation induced crosslinking in RTR and 50RTR/5APS blends. Presence of radiation sensitizers leads to simultaneous improvement in toughness and tensile strength of RTR and 50RTR/5APS blends. Elastic capacity of RTR phase was restored and interfacial adhesion enhanced in the presence of radiation sensitizers.iii