Korean researchers advance catalyst-based rubber recycling

Daejeon, South Korea – Scientists at South Korea’s KAIST have developed a new catalytic system to break down used tires into high-purity cyclic alkenes, offering a potential source of raw materials for rubber and polyamide fibres.

The research team, led by prof Soon Hyeok Hong, developed the 'dual-catalyst-based reaction system' to address long-standing challenges in processing vulcanised rubber, KAIST announced 26 June.

Conventional recycling methods such as pyrolysis decompose tire polymers at high temperatures of 350–800?°C to produce fuel oil.

However, the KAIST team noted that this approach has limitations, including high energy consumption, low selectivity, and low-quality hydrocarbon output.

To overcome these issues, the team developed a process using two catalysts: one that breaks down the bonding structure of rubber molecules; another that creates “cyclic compounds through a ring-closing reaction.”

According to the researchers, the system demonstrated selectivity of up to 92% and a yield of 82% when applied to discarded tires.

The process produces cyclopentene that can be recycled into rubber, and cyclohexene that can be used as a raw material for polyamide fibres – making them “industrially very valuable.”

“This research offers an innovative solution for the chemical recycling of waste tires,” said prof Hong.

“We aim to develop next-generation high-efficiency catalysts and lay the groundwork for commercialisation to enhance economic feasibility.”

The catalytic platform, he added, is compatible with a wide range of synthetic and waste rubbers, supporting scalable, circular solutions for the polymer and materials industries.