Thermosets
Thermosets, thermosetting plastic or thermosetting resins cure to a solid state when they reach a certain temperature (as opposed to melting like many materials), that is, their parts and properties become set. They create an infusible, insoluble network via a chemical reaction in which the whole entire heated finished object becomes in effect a single large molecule. These materials cannot be melted back down they just burn or char, so cannot be reshaped or restored to their original properties.
These thermosets have covalent intermolecular cross-links, and consist of major resin classes such as isocyanate, unsaturated polyester, formaldehyde, epoxies, and alkyds, and because of the cross-links they are extremely strong, whilst often also being lightweight. It is the strength in the cross-links that also make these products difficult to recycle.
Whilst thermoplastics have the characteristic of being able to be moulded, remoulded or recycled repeatedly, thermosets don't - although some plastics such as PVC (Polyvinyl Chloride) and PE (Polyethylene) can be processed as thermoplastics or as thermosets.
Other well known thermoset materials include:
- Polyester
- Silicone
- Melamine
- Epoxy
- Urea formaldehyde
The main advantages of thermosets are that they are very hard and rigid, very stable and resistant to high temperatures. These types of plastics can also be reinforced for extra tensile strength with materials such as Kevlar, carbon, and fibreglass. Of the total global production of plastic, thermosets account for around 11%, whilst 75% are thermosplastics that can be recycled, although it is estimated that only about 5-9% of global plastic is recycled.
Whilst most commercial plastic, both thermoset and thermoplastic, is made from fossil-based resources, both types of plastic can also be made from renewable sources, often referred to as bio-plastics. Monomers are extracted or synthesised from biomass compounds (such as sugar) and then polymerised to make bioplastics in a similar way to standard plastics.
[edit] Related articles on Designing Buildings
- Biogenic.
- Biobased materials.
- Glass reinforced plastic GRP.
- Glass fibre reinforced plastic.
- Polycarbonate plastic.
- Plastic cladding.
- Plastic coating market.
- Plastic in construction.
- Plastic in concrete.
- Recycled plastic bridges.
- Types of biobased materials.
- Thermoplastic.
- Wood plastic composites market for construction.
Featured articles and news
Investors in People: CIOB achieves gold
Reflecting a commitment to employees and members.
Scratching beneath the surface; a guide to selection.
ECA 2024 Apprentice of the Year Award
Entries open for submission until May 31.
UK gov apprenticeship funding from April 2024
Brief summary the policy paper updated in March.
For the World Autism Awareness Month of April.
70+ experts appointed to public sector fire safety framework
The Fire Safety (FS2) Framework from LHC Procurement.
Project and programme management codes of practice
CIOB publications for built environment professionals.
The ECA Industry Awards 2024 now open !
Recognising the best in the electrotechnical industry.
Sustainable development concepts decade by decade.
The regenerative structural engineer
A call for design that will repair the natural world.
Buildings that mimic the restorative aspects found in nature.
CIAT publishes Principal Designer Competency Framework
For those considering applying for registration as a PD.
BSRIA Building Reg's guidance: The second staircase
An overview focusing on aspects which most affect the building services industry.
Design codes and pattern books
Harmonious proportions and golden sections.
Introducing or next Guest Editor Arun Baybars
Practising architect and design panel review member.
Quick summary by size, shape, test, material, use or bonding..
Comments
[edit] To make a comment about this article, or to suggest changes, click 'Add a comment' above. Separate your comments from any existing comments by inserting a horizontal line.