Polymer materials – SBR versus natural rubber properties Compared to natural rubber, styrene–butadiene rubber (SBR) generally shows which of the following performance differences?

Chemical Engineering Chemical Process Difficulty: Easy
Choose an option
  • A
    Poorer tensile strength.
  • B
    poorer resistance to oxidation.
  • C
    greater amount of heat build-up under heavy loading.
  • D
    all (a), (b) and (c).

Answer

Correct Answer: all (a), (b) and (c).

Explanation

Introduction / Context:SBR is a widely used synthetic rubber in tires and general-purpose goods. Comparing it to natural rubber highlights trade-offs that guide material selection, compounding, and service environment decisions.

Given Data / Assumptions:

  • SBR (styrene–butadiene) versus NR (cis-1,4-polyisoprene).
  • Unfilled, unreinforced baseline comparison under similar test conditions.
  • Focus on tensile strength, oxidative resistance, and heat build-up (hysteresis).

Concept / Approach:Natural rubber exhibits exceptional strain-induced crystallization, delivering higher tensile strength and tear resistance. SBR lacks strong crystallization under strain; its oxidative stability is also lower without antioxidants. SBR tends to have higher hysteresis, generating more heat under cyclic loading than NR, which is critical for tire temperature rise.

Step-by-Step Solution:

Compare tensile behavior: NR > SBR in tensile strength → SBR is poorer.Assess oxidation: NR with natural antioxidants still often outperforms base SBR; SBR needs stabilizers → poorer oxidation resistance.Evaluate heat build-up: SBR higher hysteresis → greater heat under heavy loading.

Verification / Alternative check:Standard property tables for vulcanizates show NR’s superior tensile/tear and lower hysteresis versus general-purpose SBR, confirming all three statements are true simultaneously.

Why Other Options Are Wrong:Options (a), (b), and (c) each capture a true statement; hence the combined option ‘‘all (a), (b) and (c)’’ is most correct.

Common Pitfalls:Overgeneralizing after compounding: fillers (e.g., carbon black), oils, and antioxidants can significantly modify performance; the baseline material tendencies are as stated.

Final Answer:all (a), (b) and (c).

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