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.

Biocomposites of kenaf fiber (KF) and polylactic acid (PLA) were prepared by an internal mixer and compression molding. PLA was plasticized with polyethylene glycol (PEG) (10 wt%) and evaluated as the polymer matrix (p-PLA). Fiber loadings were varied between 0 and 40 wt%. The tensile, dynamic mechanical, and morphological properties and water absorption behavior of these composites were studied. Reinforcing effect of KF was observed when fiber loading exceeded 10 wt% despite of the inferior fiber-matrix adhesion observed via scanning electron microscopy (SEM). Un-plasticized PLA/KF composite exhibited higher tensile properties than its plasticized counterpart. Fiber breakage and heavily coated short pulled-out of fibers were observed from the SEM micrographs of the composite. The presence of PEG might have disturbed the fiber-matrix interaction between KF and PLA in the plasticized composites. Addition of PEG slightly improved the un-notched impact strength of the composites. Dynamic mechanical analysis showed that the storage and loss moduli of p-PLA/KF composites increased with the increase in fiber loading due to increasing restrictions to mobility of the polymer molecules. The tan delta of the composites in contrast showed an opposite trend. p-PLA and p-PLA/KF composites exhibited non-Fickian behavior of water absorption. SEM examination revealed microcracks on p-PLA and p-PLA/KF surfaces.

No abstract

No abstract

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

No abstract

Blends of polylactic acid (PLA) and nanohydroxyapatite (NHA) were prepared through melt‐mixing by varying the composition of NHA from 1 to 5 wt%. The tensile properties of the PLA‐1 wt% NHA nanocomposite exhibited higher values than neat PLA. Beyond 1 wt% NHA, a drop in tensile properties of the PLA–NHA nanocomposites was observed due to agglomeration and poor interfacial adhesion between NHA and PLA. Therefore, NHA was surface modified (mNHA) using three different surface modifiers namely, 3‐aminopropyl triethoxysilane (APTES), sodium n‐dodecyl sulfate (SDS) and polyethylenimine (PEI). The surface treatment of NHA was studied through Fourier transform infrared spectroscopy (FTIR) and energy dispersive X‐ray (EDX). Results revealed that the tensile properties increased in order of PLA‐5 wt% mNHA (APTES) followed by PLA‐5 wt% mNHA (SDS), whereas PEI modified NHA resulted in lower tensile properties. Further, increasing mNHA loading to 30 wt%, decreased the tensile strength due to agglomeration of mNHA. POLYM. COMPOS., 39:2880–2888, 2018. © 2016 Society of Plastics Engineers

Dependence on automobiles has led to a huge amount of waste tires produced annually around the globe. In this study, the feasibility of recycling these waste tires by blending reclaimed waste tire rubber (RTR) with poly(ethylene-co-vinyl acetate) (EVA) and electron beam irradiation was studied. The RTR/EVA blends containing 100-0 wt% of RTR were prepared in the internal mixer followed by electron beam (EB) irradiation with doses ranging from 50 to 200 kGy. The processing torques, calorimetric and dynamic mechanical properties of the blends were studied. Blends were found to have lower processing torque indicating easier processability of RTR/EVA blends compared to EVA. RTR domains were found to be dispersed in EVA matrix, whereas, irradiation improved the dispersion of RTR into smaller domains in EVA matrix. Results showed the addition of EVA improves the efficiency of irradiation induced crosslink formation and dynamic mechanical properties of the blends at the expense of the calorimetric properties. Storage and loss modulus of 50 wt% RTR blend was higher than RTR and EVA, suggesting partial miscibility of the blend. Whereas, electron beam irradiation improved the calorimetric properties and dynamic mechanical properties of the blends through redistribution of RTR in smaller domain sizes within EVA.