The material. Borosilicate glass is soda lime glass with most of the lime replaced by borax, B203. It has a higher melting point than soda-lime glass and is harder to work, but it has a lower expansion coefficient and a high resistance to thermal shock, so it is used for glassware and laboratory equipment. Composition […]
Category: Materials and the Environment: Eco-Informed Material Choice
Soda-lime glass
The material. Soda-lime glass is the glass of windows, bottles, and light bulbs, used in vast quantities, the commonest of them all. The name suggests its composition: 13-17% NaO (the "soda"), 5-10% CaO (the "lime") and 70-75% SiO2 (the "glass"). It has a low melting point, is easy to blow and mold, and it is […]
Alumina
The material. Alumina (Al2O3) is to technical ceramics what mild steel is to metals—cheap, easy to process, the workhorse of the industry. It is the material of spark plugs, electrical insulators, and ceramic substrates for microcircuits. In single crystal form, it is sapphire, used for watch faces and cockpit windows of high-speed aircraft. More usually […]
Concrete
The material. Concrete is a composite, and a complex one. The matrix is cement; the reinforcement, a mixture of sand and gravel ("aggregate") occupying 60-80% of the volume. The aggregate increases the stiffness and strength and reduces the cost (aggregate is cheap). Concrete is strong in compression but cracks easily in tension. This is countered […]
Stone
The material. Stone is the most durable of all building material. The Pyramids (before 3000 BC), the Parthenon (5th century BC), and the cathedrals of Europe (1000-1600 AD) testify to the resistance of stone to attack of every sort. It remained the principal material of construction for important buildings until the early 20th century; the […]
Brick
The material. Brick is as old as Babylon (4000 BC) and as durable. It is the most ancient of all manmade building materials. The regularity and proportions of bricks make them easy to lay in a variety of patterns, and their durability makes them an ideal material for building construction. Clay, the raw material from […]
Ceramics and glasses
Ceramics are materials of both the past and the future. They are the most durable of all materials—ceramic pots and ornaments survive from 5000 BC; Roman cement still bonds the walls of villas. It is ceramics ‘ durability, particularly at high temperatures, that generates interest in them today. They are exceptionally hard (diamond, a ceramic, […]
Polychloroprene (Neoprene, CR)
The material. Polychloroprenes (Neoprene, CR), the materials of wetsuits, are the leading nontire synthetic rubbers. First synthesized in 1930, they are made by a condensation polymerization of the monomer 2-chloro-1,3 butadiene. The properties can by modified by copolymerization with sulfur, with other chloro-butadienes and by blending with other polymers to give a wide range of […]
EVA
The material. Ethylene-Vinyl-Acetate elastomers (EVA) are built around polyethylene. They are soft, flexible, and tough and retain these properties down to -60°C and have good barrier properties as well as FDA approval for direct food contact. EVA can be processed by most normal thermoplastic processes: co-extrusion for films, blow molding, rotational molding, injection molding, and […]
Butyl rubber
The material. Butyl rubbers (BRs) are synthetics that resemble natural rubber in properties. They have good resistance to abrasion, tearing, and flexing, with exceptionally low gas permeability and useful properties up to 150°C. They have low dielectric constant and loss, making them attractive for electrical applications. Composition (CH2-C(CH3)-CH-(CH2)2-C(CH3)2)n General properties Density 900 – 920 kg/m3 […]