Dear Akilan Ilango,

Styrene-butadiene rubber (SBR) can undergo a degree of cross-linking or network formation even without the addition of conventional vulcanizing agents like sulfur. This cross-linking occurs due to the inherent properties of SBR and its interaction with certain components, such as cellulose nanocrystals (CNC), especially at higher loadings of CNC/SBR. Here's a simplified explanation of how this can happen:

It's important to note that the degree of cross-linking in SBR without vulcanizing agents is typically lower than that achieved through conventional vulcanization processes. The resulting material may exhibit improved mechanical properties and thermal stability compared to non-cross-linked SBR but may not match the performance of fully vulcanized rubber.

The extent of cross-linking in CNC/SBR compositions without vulcanizing agents can vary based on factors like CNC loading, processing conditions, and the specific SBR formulation. Researchers often study these interactions to tailor the properties of the composite material for various applications.