Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras
A Method Of Cross-linking Of Rubber With Multifunctional Thiol And The Applications Thereof
Technology Category/Market
Category- Chemistry and Chemical Analysis / Other Technologies
Industry:
Synthetic Rubber Manufacturing; Vulcanizable Elastomers; Rubber Product Manufacturing, Tires
Applications:
Solution‑Cast Rubber Films; Coated Textiles and PPE; Rubber‑Coated Biocomposites; Solid‑State Compounded Belts and Gaskets; Custom Rubber Compositions
Market report:
The global rubber market was valued at USD 48.49 billion in 2024 and is projected to grow to USD 88.06 billion by 2035 with a CAGR of 5.57%.
Problem Statement
- Three‑dimensional cross‑linking transforms soluble polymers into durable, resilient materials critical for automotive tyres, medical gloves, seals and sustainable manufacturing.
- Traditional sulfur or peroxide vulcanization irreversibly forms C–S or C–C bonds that require high temperatures and yield non‑degradable products while causing skin‑allergies.
- Further, Thermal (AIBN) and photochemical (UV/DMPA) thiol‑ene methods need high heat or suffer poor bulk penetration and produce toxic by‑products.
- There is a need for an ambient‑temperature, method for cross‑linking that yields biodegradable, low‑energy, non‑toxic rubber with tunable properties that is suitable for broad substrate coatings.
Technology
- Rubber dissolved in toluene is mixed with pentaerythritol tetrakis(3‑mercaptopropionate) (PENTA) and CeCl₃, stirred 0.5 h at 20–40 °C, then solvent‑cast and cured 18–30 h to form insoluble, cross‑linked networks.
- Rubber, PENTA and CeCl₃ are masticated on a two‑roll mill, enabling large‑scale belt, gasket or hose production without solvents, achieving full cross‑link density in 24 h at ambient temperature.
- Method applies to natural rubber (cis‑1,4‑isoprene), synthetic rubbers (polybutadiene, styrene‑butadiene, chloroprene), yielding high yields of cross‑linked gel regardless of double‑bond activation.
- The multifunctional thiol introduces ester bonds into cross‑links, which can be cleaved enzymatically (esterase) or by acid hydrolysis, reverting to biodegradable rubber fragments.
- Compatible with additives (cellulose, carbon black, CaCO₃, silica, lignin, chitosan) at up to 12.5 wt%, enabling tailored mechanical, thermal and surface properties for targeted licenses.
Key Features/Value Proposition
- The method operates at room temperature, reducing energy consumption compared to thermal and sulfur-based processes.
- By avoiding sulfur and high heat, the process minimizes toxic byproduct generation and improves biodegradability.
- Versatile Applications: Applicable to natural and synthetic rubbers, including rubber-coated fabrics and biodegradable fibers.
- The process eliminates the need for complex photochemical equipment, making it more accessible.
- The use of cerium chloride enables the production of recyclable and degradable rubber products, addressing global sustainability challenges.
Questions about this Technology?
Contact for Licensing
Research Lab
Prof. Dhamodharan R
Department of Chemistry
Intellectual Property
- IITM IDF Ref 3011
- IN 565314 Patent Granted
Technology Readiness Level
TRL 4
Technology Validated in Lab