ADVANCEMENTS IN TIRE INNER LINER TECHNOLOGIES: A COMPREHENSIVE REVIEW OF MATERIALS AND PERFORMANCE CHARACTERISTICS

ABSTRACT The tire inner liner is a thin, air-impermeable layer composed of natural or synthetic rubber engineered to retain internal air pressure, thereby enhancing fuel efficiency and prolonging tire service life. We present a comprehensive and timely review of the current state of research on tire inner liners, with particular emphasis on material development and performance optimization. We introduce the fundamental role and design principles of inner liners, followed by a critical analysis of recent advancements in the selection of elastomers and functional fillers; and address the recycling and reuse of inner liner materials, highlighting environmentally sustainable and economically feasible approaches. A key novelty of this work lies in its coverage of a research area that has received minimal attention in the literature. Despite the critical importance of inner liners in tire performance and sustainability, comprehensive reviews on this topic are scarce, resulting in a significant knowledge gap. By systematically synthesizing historical research and identifying emerging trends and challenges, this review not only fills a crucial void in the academic and industrial literature but also provides valuable guidance for researchers, entrepreneurs, and tire manufacturers seeking to develop next-generation sustainable tire technologies.