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Mingmin Zhen, Jinglu Wang, Lei Zhou, Tian Fang, Long Quan

Xiang Wang, Dingxian Wang, Canran Xu, Xiangnan He, Yixin Cao, Tat-Seng Chua

Wanjun Zhong, Duyu Tang, Nan Duan, Ming Zhou, Jiahai Wang, Jian Yin

N. B. Guerra, Giovana Sant'Ana Pegorin, M. H. Boratto, N. R. de Barros, Carlos Frederico de Oliveira Graeff, R. Herculano

The past decades have witnessed tremendous progress in biomaterials in terms of functionalities and applications. To realize various functions such as tissue engineering, tissue repair, and controlled release of therapeutics, a biocompatible and biologically active material is often needed. However, it is a difficult task to find either synthetic or natural materials suitable for in vivo applications. Nature has provided us with the natural rubber latex from the rubber tree Hevea brasiliensis, a natural polymer that is biocompatible and has been proved as inducing tissue repair by enhancing the vasculogenesis process, guiding and recruiting cells responsible for osteogenesis, and acting as a solid matrix for controlled drug release. It would be extremely useful if medical devices can be fabricated with materials that have these biological properties. Recently, various types of natural rubber latex-based biomedical devices have been developed to enhance tissue repair by taking advantage of its biological properties. Most of them were used to enhance tissue repair in chronic wounds and critical bone defects. Others were used to design drug release systems to locally release therapeutics in a sustained and controlled manner. Here, we summarize recent progress made in these areas. Specifically, we compare various applications and their performance metrics. We also discuss critical problems with the use of natural rubber latex in biomedical applications and highlight future opportunities for biomedical devices produced either with pre-treated natural rubber latex or with proteins purified from the natural rubber latex.

S. Poovaneshvaran, M. M. Mohd Hasan, R. Putra Jaya

Abstract The objective of this study is to investigate the rheological properties, bonding and resistancetoshear of the rubberized modified binders under different conditions. A base asphalt binder with penetration grade 60/70 was utilised in this study. The crumb rubber and natural rubber latex were added at different percentages for the modified bitumen production, and computed based on the mass of bitumen. Silane additives at the rate of 0.1% by mass of asphalt binder were used as a surfactant. A series of rheological properties and recovery test were conducted on all binders. While bond test and Layer-Parallel Direct Shear (LPDS) test were carried out in order to simulate the crack movement of pavement. The results show that the addition of crumb rubber and latex positively impacts the performance of the asphalt binder. The crumb rubber and natural rubber latex modified asphalt binder has comparatively identical elastic recovery outcomes, while it also helps in enhancing the stiffness in terms of softening and penetration value. However, natural rubber latex modified asphalt binder performed much better than crumb rubber modified asphalt binder in terms of torsional recovery. Whereas, rotational viscosity test has been useful in adopting the suitable temperature which is 160 °C in order to satisfy the needs of better workability and to ensure it is pumpable. Storage stability test proved that the modified asphalt binders are homogenous since the temperature differences are less than 5 °C. The dynamic shear rheometer (DSR) test proved that the modified asphalt binder has better resistance to rutting. Through DSR findings and activation energy, the modified asphalt binder were catogorize as less susceptible to temperature changes. Finally, the crumb rubber modified asphalt binder did well in terms of bonding strength, while the natural rubber latex modified asphalt binder performed well in terms of resistance to shear. Overall, both rubberized modified binders performed better than the control sample.