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Polymethyl methacrylate (PMMA)
3-8 usd/kg
Polymethyl methacrylate (PMMA), acrylic, is a transparent plastic often compared to glass. Indeed, the two materials are used in many of the same applications – glazing, aquariums, household items, tableware and furniture, for example – with acrylic being lighter, more resistant to impact and easier to form into complex and intricate shapes. The disadvantages of acrylic, when compared to glass is that it is not inert (glass is virtually inert) and will crack and weaken if exposed to certain chemicals, it softens and melts at much lower temperatures (160 degC versus 1,700 degC for glass), and it is less scratch resistant.
As a transparent plastic, it is available in standard and custom colours, from muted tones through saturated fluorescents. Edge glow is the result of light passing through the surface and refracting internally until it meets a cut edge in tinted or semi-transparent materials. This phenomenon is utilised in signage, lighting and instrument panels, for example, that are made from acrylic. A cut edge may be the perimeter, or a score on the surface, such as made by laser cutting or engraving.
Sustainability concerns
Non-renewable ingredients
Raw material generates polluting by-products
Low circularity potential
Microplastics
Polymer concrete (PC) is a composite material reinforced with aggregate and sometimes powder and fibre – the Portland cement is partially (>5%) or wholly replaced with polymer. Instead of cement binding the aggregate, it is held together by the polymer matrix, which forms a very strong bond. Suitable polymers include polyester resin, epoxy, vinyl ester, acrylic and many others, both thermoset (form permanent cross-links) and thermoplastic (soften when heated). Choice depends on the requirements of the applications, such as whether it will be exposed to weathering, sunlight and temperature extremes. For example, epoxy has the best mechanical properties, polyester is the least expensive and acrylic has good resistance to weathering. Aggregates and fibres (AR-glass and carbon for example) reinforce the polymer matrix, and as with any composite, greatly influence mechanical properties.
A major advantage of PC is, unlike Portand cement concrete, there are no voids left once curing is complete. Regular concrete is very cost-effective, but it suffers from low strength and flexural properties, which are exasperated by its poor resistance to water penetration, freeze-thaw phenomena and acids. Additional advantages of PC include rapid curing, mechanical properties, resistance to chemicals and corrosion, and good moulding properties. It also bonds very well to steel, and other materials used in structural applications – much better than cement.
Applications include pavements, pipelines, bridges, dams and floors. It is also used extensively as a repair material. Precast PC is used in the production of tanks (such as for acids), paving, manhole covers, drains and barriers, for example.