Working principle of Thiourea as a rubber vulcanization accelerator

When Thiourea is used as a rubber vulcanization accelerator, it has a unique working principle:

During the rubber vulcanization process, Thiourea molecules can actively participate in the cross-linking reaction between rubber molecules and sulfur.

First, Thiourea has certain active groups, which can chemically adsorb with the active sites on the rubber molecular chain, shorten the distance between the rubber molecules and sulfur, and make them easier to contact each other.

When the temperature rises to the required conditions for the vulcanization reaction, the sulfur atoms and nitrogen atoms in Thiourea can activate the surrounding sulfur molecules and enhance their reactivity.

On the one hand, Thiourea promotes sulfur to form more reactive polysulfides, which can quickly react with the double bonds in the rubber molecular chain to build a sulfur bridge cross-linking structure between the rubber molecular chains, thereby forming a three-dimensional network structure of the rubber, greatly improving the physical and mechanical properties of the rubber, such as improving the tensile strength, wear resistance and elasticity of the rubber.

On the other hand, the structural characteristics of Thiourea itself enable it to regulate the vulcanization reaction rate. It can stabilize free radical intermediates in the vulcanization reaction, prevent excessive accumulation of free radicals and cause side reactions, and ensure that the vulcanization reaction proceeds smoothly and efficiently in the direction of forming an ideal cross-linked structure, ultimately enabling rubber products to achieve good vulcanization effects and meet the stringent requirements of different industrial fields for rubber performance.