Preventing crystallisation in celluloid: which additive is used as a plasticiser to inhibit crystallisation and embrittlement?

Introduction / Context:
Celluloid, an early plastic based on nitrocellulose, requires plasticisation to maintain flexibility and reduce brittleness. Classic historical formulations used a specific small molecule to soften the matrix and suppress crystallisation.

Given Data / Assumptions:

• Celluloid = nitrocellulose + plasticiser.
• We seek the traditional plasticiser.
• Additive should reduce crystallisation and improve toughness.

Concept / Approach:
Camphor is the historical and archetypal plasticiser for celluloid. It intercalates between nitrocellulose chains, reducing intermolecular forces, lowering glass transition temperature, and suppressing crystallisation that would otherwise embrittle the material. Glycerol is a plasticiser for other systems (e.g., PVC derivatives), and “nitrocellulose” is the polymer itself, not an additive.

Step-by-Step Solution:
Identify celluloid composition.Recall camphor as the key plasticiser.Eliminate alternatives that do not match historic practice.

Verification / Alternative check:
Materials histories and safety data sheets for legacy celluloid goods specify camphor as the principal plasticiser.

Why Other Options Are Wrong:
Glycerol: not the classic plasticiser for celluloid.Nitrocellulose: base polymer, not an additive.None: invalid because camphor is used.

Common Pitfalls:
Confusing polymer with its modifier; overlooking the historical role of camphor.

Final Answer:
Camphor