Category: Materials and the Environment: Eco-Informed Material Choice

Polyester

The material. Polyesters can be thermosets, thermoplastics, or elastomers. The unsaturated polyester resins are thermosets. Most polyester thermo­sets are used in glass fiber/polyester composites. They are less stiff and strong than epoxies, but they are considerably cheaper. This record is for thermosetting polyester. It cannot be recycled. Composition (OOC—C6H4—COO—C6H10)n General properties Density 1040 – 1400 […]

Epoxies

The material. Epoxies are thermosetting polymers with excellent mechani­cal, electrical, and adhesive properties and good resistance to heat and chemical attack. They are used for adhesives (Araldite), surface coatings, and, when filled with other materials such as glass or carbon fibers, as matrix resins in composite materials. Typically, as adhesives, epoxies are used for high-strength […]

Polylactide (PLA)

The material. Polylactide (PLA) is a biodegradable thermoplastic derived from natural lactic acid from corn, maize, or milk. It resembles clear poly­styrene and provides good aesthetics (gloss and clarity), but it is stiff and brittle and needs modification using plasticizers for most practical applica­tions. It can be processed like most thermoplastics into fibers, films, ther […]

Polystyrene (PS)

The material. Polystyrene is an optically clear, cheap, easily molded poly­mer, familiar as the standard "jewel" CD case. In its simplest form PS is brittle. Its mechanical properties are dramatically improved by blending with polybutadiene but with a loss of optical transparency. High-impact PS (10% polybutadiene) is much stronger, even at low temperatures (meaning strength […]

Polyvinylchloride (tpPVC)

The material. PVC (vinyl) is one of the cheapest, most versatile, and, with polyethylene, the most widely used of polymers and epitomizes their multi­faceted character. In its pure form—as a thermoplastic, tpPVC—it is rigid and not very tough; its low price makes it a cost-effective engineering plas­tic where extremes of service are not encountered. Incorporating […]

Polycarbonate (PC)

The material. PC is one of the "engineering" thermoplastics, meaning that they have better mechanical properties than the cheaper "commodity" polymers. The benzene ring and the —OCOO-carbonate group combine in pure PC to give it its unique characteristics of optical transparency and good toughness and rigidity, even at relatively high temperatures. These properties make PC […]