thermoset
Học thuậtThân thiện
Definition
Adjective: 1. Permanently hardening when heated: Describing a material, especially a synthetic polymer or plastic, that undergoes an irreversible chemical change when heated or cured, becoming hard, rigid, and infusible. Once set, it cannot be remelted or reshaped by reheating.
Usage
- This term is primarily used in industrial, manufacturing, and materials science contexts to classify polymers and describe their properties.
- It is often used attributively (before a noun) to modify words like , , , or .
- The process is called .
Examples
Attributive use:
- Epoxy is a classic thermoset adhesive used in construction and aerospace.
- The electrical switch housing is made from a durable thermoset plastic.
- Bakelite was one of the first commercially successful thermoset polymers.
Predicative use:
- Once cured, the resin becomes completely thermoset.
- This type of plastic is thermoset, so you cannot recycle it by melting it down.
Advanced Usage
- Thermoset vs. Thermoplastic: This is a fundamental dichotomy in polymer science. A (e.g., epoxy, vulcanized rubber, polyurethane foam) permanently hardens. A (e.g., polyethylene, PVC, nylon) softens when heated and hardens when cooled, allowing it to be remolded repeatedly.
- Example: For this application, we need a thermoset material for its high heat resistance, not a thermoplastic.
Variants and Related Words
- Thermosetting (adj): The process or property of becoming thermoset. Often used interchangeably with "thermoset" as an adjective.
- Example: Phenolic resins have strong thermosetting properties.
- Thermoset (noun): A material that has this property.
- Example: Fiberglass is often combined with a thermoset like polyester resin.
Synonyms
- Heat-set
- Thermohardening
- Irreversible (in this specific context)
Antonyms
- Thermoplastic (a polymer that becomes pliable or moldable above a specific temperature and solidifies upon cooling, allowing repeated reshaping)
Adjective
- having the property of becoming permanently hard and rigid when heated or cured
- the phenol resins and plastics were the original synthetic thermosetting materials