Organic Accelerators, Sulfur-Free Crosslinking Agents, And Green Vulcanization Chemistry For Sustainable Rubber Manufacturing: A Systematic Review And Meta-Analysis Framework

Abstract

The development of sustainable rubber manufacturing has accelerated research on environmentally friendly vulcanization systems that minimize hazardous chemicals while maintaining desirable material performance. Emerging approaches, including sulfur-free crosslinking, bio-based curing agents, organic peroxides, dynamic covalent chemistry, and reversible Diels–Alder systems, offer promising alternatives to conventional sulfur/ZnO curing. However, existing evidence remains fragmented, limiting the establishment of unified design principles for green vulcanization. This study presents a systematic literature review and proposed meta-analysis framework of green vulcanization technologies for natural and synthetic rubbers following PRISMA 2020 guidelines. Peer-reviewed studies published between 2000 and 2026 were systematically identified and synthesized to evaluate the effects of organic accelerators and sustainable curing systems on mechanical properties, cure characteristics, crosslink density, thermal stability, aging resistance, and environmental performance. The proposed statistical framework incorporates random-effects meta-analysis, subgroup analysis, meta-regression, sensitivity analysis, and publication bias assessment to identify key factors influencing vulcanization performance. Furthermore, this review introduces the Green Vulcanization Chemistry Index (GVCI), a novel multi-criteria framework integrating mechanical performance, curing efficiency, environmental impact, toxicity, energy efficiency, and industrial scalability for the standardized evaluation of sustainable curing technologies. The proposed framework provides a quantitative basis for comparing emerging vulcanization systems, identifying research gaps, and supporting the development of environmentally responsible, high-performance rubber materials.