Recyclability of polymer scrap: which among the following scrap types can be remelted, recycled, and re-utilised most readily?
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ABakelite (phenolic thermoset)
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BEpoxy resin (thermoset)
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CPolythene (thermoplastic)
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DNone of these
Answer
Correct Answer: Polythene (thermoplastic)
Explanation
Introduction / Context:Polymer recyclability depends strongly on whether the material is a thermoplastic or a thermoset. This question checks the practical distinction from a waste-processing perspective.
Given Data / Assumptions:
- Bakelite and epoxy resins are thermosets.
- Polythene (polyethylene) is a thermoplastic.
- We consider mechanical recycling by remelting and re-extrusion.
Concept / Approach:Thermoplastics soften and flow when heated, so their scrap can often be reprocessed by melting. Thermosets are crosslinked irreversibly and do not melt; they degrade on heating, making remelting impossible. Therefore, among the choices, polythene is the readily recyclable material via melt reprocessing.
Step-by-Step Solution:Classify materials: polythene = thermoplastic; Bakelite/epoxy = thermosets.Apply recyclability rule: only thermoplastics remelt.Select polythene accordingly.
Verification / Alternative check:Recycling codes and industry practice list polyethylene (PE) among the most recycled plastics (e.g., HDPE bottles, LDPE films) by melt reprocessing.
Why Other Options Are Wrong:Bakelite, epoxy: crosslinked networks do not remelt; only downcycling as fillers/ground powders is possible.None of these: incorrect because polythene qualifies.
Common Pitfalls:Assuming all plastics recycle identically; cure chemistry dictates feasibility.
Final Answer:Polythene (thermoplastic)