Reduction in Sulfur Diffusion in Recycled Ground Rubber-Containing Compounds to Improve Tensile Strength.

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Engineering

Background:

• Recycling end-of-life rubber is crucial for the rubber industry's sustainability.
• Current methods like devulcanization, pyrolysis, and using ground rubber (GR) have limitations.
• Sulfur diffusion from the matrix into GR particles reduces the mechanical properties of recycled rubber.

Purpose of the Study:

• To investigate a method for reducing sulfur diffusion into ground rubber particles.
• To improve the mechanical properties of recycled rubber compounds containing ground rubber.
• To enhance the utilization of recycled rubber in demanding applications.

Main Methods:

• Prevulcanizing the green rubber matrix material before incorporating ground rubber.
• Compounding and vulcanizing prevulcanized matrix material with ground rubber.
• Evaluating the mechanical properties of the resulting vulcanizates.

Main Results:

• Prevulcanization effectively reduced sulfur diffusion from the matrix into the ground rubber particles.
• Ground rubber-containing vulcanizates exhibited significantly improved mechanical properties compared to those without prevulcanization.
• The crosslink density of the matrix was better maintained, leading to enhanced performance.

Conclusions:

• Blocking sulfur diffusion by prevulcanizing the matrix is a viable strategy to improve recycled rubber quality.
• This approach can significantly increase the value and application range of ground rubber.
• While currently lab-scale, this method offers potential for industrial application in rubber recycling.