SBR identity check:\nStyrene–butadiene rubber (SBR) should be classified as which of the following?

Introduction / Context:
SBR is one of the most widely used synthetic rubbers, commonly blended with natural rubber in tire treads and used independently in many rubber goods. Understanding its classification is foundational before discussing its properties or processing routes (e.g., emulsion vs. solution SBR).

Given Data / Assumptions:

• SBR is a copolymer of styrene and butadiene.
• It is made synthetically via radical polymerisation.

Concept / Approach:
The correct classification is “a synthetic polymer.” It is neither natural rubber nor silicone; it is not a monomer. SBR can be compounded and vulcanised, but it is not a thermosetting phenolic network like Bakelite.

Step-by-Step Solution:

Verification / Alternative check:
Rubber technology references list SBR among synthetic elastomers (with NBR, EPDM, etc.).

Why Other Options Are Wrong:

• Natural rubber: derived from latex polyisoprene; not SBR.
• Silicone rubber: polysiloxane family, unrelated.
• Monomer: SBR is the polymer, not a monomer.

Common Pitfalls:
Confusing SBR with SBS (styrene-butadiene-styrene block copolymer); both are synthetic but distinct in structure and properties.

Final Answer:
A synthetic polymer