Week 5
Synthetic Materials
The term synthetic is used to describe materials that are derived by chemical reactions. Some synthetic materials are also found in nature but others are not, and some materials come in both a natural and synthetic form. The distinction between natural and synthetic can sometimes be hazy. Examples – diamond, latex, rubber
- Plastics
Plastics are also called polymers, which are long-chain molecules. Most plastics are thermoplastics, which means that they can be reheated and reformed many times. A few plastics are thermosets – once formed, they can’t be reheated. There are two types of polymers based on how they are made: organic polymers and inorganic polymers.- Organic polymers are plastics made from hydrocarbons - crude oil & natural gas. The first organic polymer was Bakelite, invented in 1907 by Leo Baekland. Bakelite was also the first thermoset plastic.
- Inorganic polymers are plastics made from cellulose or other non-hydrocarbon materials. The earliest plastics were inorganic, including celluloid.
- lightweight
- chemical-resistant
- thermal and electrical insulation
- can be formed into almost any shape
- Most plastics can be recycled. The recycling codes on plastics help recyclers know which plastic an item is made of. Plastics that can’t be recycled can be burned as fuel in WTE (waste to energy) systems.
Common plastics used in interiors:
- Nylon – carpets, textiles
- Polyester – carpet, textiles, bedding, wall coverings, cushion fill
- Rayon – textiles
- Acrylic – textiles, area rugs, solid-surface materials, paints, bath & shower enclosures
- Perspex acrylic – glass substitute
- Vinyl (PVC) – flooring, wallcovering, windows & glass doors, wall & ceiling panels
- Olefin – carpet & carpet backing, textiles, wall coverings
- PLA – textiles
- Modacrylic – flame-resistant textiles
- Polypropylene – furniture, household objects
- Polystyrene – simulated wood & plaster moulding
- Polyvinylacetate – paints, sealers, adhesives
- Teflon – protective coating for fabrics
- Melamine – laminates
- Urethane – paints, cushions, protective coating on flooring
- Urethane foam – carpet padding
- Epoxy – coatings & adhesives
- Synthetic rubber – non-slip devices, flooring
- Neoprene (synthetic foam rubber) - cushions
- Silicone – sealants, adhesives, coating
Links:
- How to Process Plastics from the British Plastics Federation
- The History of Plastics from the American Plastics Council
- Plastics 101 from the American Chemistry Council
- Other Petroleum-based Materials
There are other petroleum-based materials used in interiors. Most petroleum-based materials are hazardous in some way (flammable, VOCs, carcinogen).- Solvents (mineral spirits, naptha, xylene) - used in alkyd (oil-based) paints, thinners, & varnishes; also in some adhesives
- Formaldehyde – preservative & bonding agent in textiles, carpets, manufactured wood products
- Asphalt (bitumen) – older homes may have asphalt floor tiles. Asphalt is also used as an adhesive and sealant (black mastic was widely used as a flooring adhesive). Asphalt felt or building paper is used as a moisture barrier under some types of flooring
Hybrid Materials
Some materials are a mix of natural and synthetic ingredients, or are made from natural ingredients that have been modified to an extent that they no longer seem natural. Hybrids are usually not sustainable or recyclable (though possibly downcyclable), and often have high embodied energy.
- Cementitious Materials
Portland cement is used to make concrete, mortar, and grout. It is produced by heating limestone (and sometimes other minerals) in a kiln to very high temperatures, then grinding with a bit of gypsum. Cement has many uses, but has high embodied energy, and is not recyclable - although the final materials (concrete) may be downcycled.
Fly ash cement contains up to 30% fly ash, a byproduct of burning coal. It is environmentally preferable over regular Portland cement.
Mortar is a stiff mixture of cement, coarse sand, water, and lime, used in masonry walls and for a substrate under tile floors.
Grout is a thin mixture of cement, water, and fine sand, used to fill spaces between tiles. Unsanded grout is used with tiles that require smaller spacing, including natural stone tiles.
Cast stone is a mixture of cement, sand, and just enough water to make it stick together. It is used as a simulated limestone for decorative masonry, often fireplace surrounds.
Links: - Terrazzo
Terrazzois a mixture of aggregate (often marble) and cement binder that is ground and polished. Epoxy terrazzo uses an epoxy binder instead of cement. Terrazzo is usually used for commercial flooring, but can be used for countertops and other applications.
EnviroGlas is a brand of terrazzo that uses recycled glass or porcelain chips instead of stone.
Engineered stone is basically a terrazzo, using crushed stone (granite or other) with a cement or epoxy binder.
Links: - Ceramics and fired clays
Clay is a material made of a number of minerals that is pliable when wet, and become very hard when fired. Ceramics, such as terra cotta and porcelain, are made of different clays. Some ceramics can be partially recycled into clay for new ceramics.
Most fired clays can be glazed or unglazed; unglazed tiles resist wear better than glazed. The hardness and permeability is dependent on the type and quality of clays used and the firing temperature.
Ceramics are typically used as tiles, but have also been used as decorative additions to masonry construction.- Bricks are made of unrefined clay that is pressed into molds and fired. There is a range of grades as well as colors. Handmade brick and salvaged antique brick are available but more expensive.
- Brick pavers are thinner than standard bricks, and are fired at a higher temperature to be more durable.
- Fire brick is made of different clay and is used to line fireplaces.
- Ceramic tiles can be glazed or unglazed, come in many colors and patterns.
- Porcelain tiles are harder ceramics with low absorbency. Made from different clays and fired at a higher temperature than standard ceramics.
- Terracotta and saltillo tiles are made from local clays, which give them their color, and tend to be very absorbent. Come in both glazed & unglazed. Acquire a patina with age.
- Quarry tiles are also made from natural clays, traditional in the UK, and usually come in earth tones. The color is from the clays, so it through the tile. Usually unglazed.
- Encaustic tiles have the pattern inlaid into the tile with different colored clays instead of applied to the surface as a glaze. They are usually unglazed.
- Mosaic tiles are made of any ceramic or glass tiles. They are small tiles that are usually sold attached to a net backing
Links:
- Glass
Glass is made mostly of silica, with other ingredients that add different properties to the glass. It is heated until molten, and then formed. Glass is made in many forms: insulating, laminated, tempered, heat-strengthened, silk-screened, spandrel, hurricane-resistant, acoustical, blast-mitigating, and more.
- Architectural Glass is a term that encompasses any glass used in a building, from windows to shower enclosures.
- Float glass is sheet glass made by floating molten glass on a bed of molten metal. Most architectural glass is float glass.
- Safety glass is used where broken glass is an issue. Tempered glass breaks into small pieces that are not sharp; mesh glass will break but not shatter; laminated glass is made of 2 or more glass sheets with a layer of vinyl, polyester, urethane, or resin in between, which holds the glass in place when broken.
- Mirrors are made by applying silver nitrate to clear or tinted glass. The silver is protected by a layer of copper, then a protective coating to prevent oxidation.
- Glass tile is formed by placing molten glass in molds or by cutting and polishing thick glass sheets. Is used like ceramic tile, but should not be used in showers or other places subject to quick changes in temperature.
- Glass block is made by fusing together 2 pressed-glass half-blocks and partially evacuating the center to create a weak vacuum. They come in many patterns and sized, and are not used as load-bearing materials.
- Art Glass includes stained and leaded glass, fused glass, and other types of artwork created using glass.
- Fiberglass is glass that is spun into very long, thin fibers. It is an excellent insulator, and is fire-resistant. It is used alone or as a composite material with polyester, vinyl, or epoxy resins. Formed bathtubs are sometimes made of fiberglass composite.
- Glass-ceramics are materials that can withstand high temperatures and thermal shocks, used for flat cooktops.
Assignments:
Study the material presented in class this week. Visit the links given. There will be a quiz next week.