Acetal, also called polyformaldehyde or polyoxymethylene (POM) is a high volume engineering plastic. The annual worldwide production lies in the range of half a milliom tons. It is known for its high dimensional stability, hardness, high flexural and tensile strength and outstanding creep resistance. These qualities allow POM to be used as a replacement for metal parts. Along with its copolymer resins, it is widely used as an engineering plastic across almost every industry. This includes mechanical, automotive, plumbing, hardware, and machinery parts as well as electronic and electrical components.
Acrylic:
Polymethyl methacrylate (PMMA,
Plexiglas) is an amorphous commodity thermoplastic
that can be easily processed and converted into many semi-finished products like films, rods, tubes, and sheets. It has high transparency and excellent weatherability but is rather brittle. To increase its toughness, it is
sometimes modified with core-shell rubber.
Plexiglas is often an economical alternative to polycarbonate (PC) when high toughness and impact strength is not required. It is used for signs, optical fibers, architectural structures, tail lights, bathtubs and sanitary fixtures, to name only a few products.
Acrylic fibers are synthetic fibers made from polyacrylonitrile with an average molecular weight of about 100,000. For a fiber to be called "acrylic" in the US, the polymer must contain at least 85 percent acrylonitrile monomer. Typical co-monomers are vinyl acetate and methyl acrylate. This fiber was first created by DuPont in 1941 and trademarked under the tradename Orlon. It is manufactured as a filament, and then cut into short staple length fibers similar to wool hairs, and spun into yarns. Acrylic fabrics are lightweight, soft, and warm, with a wool-like feel. It can be made to mimic other fibers, such as cotton and wool or can be blended with them.
Acrylic styrene acrylonitrile terpolymer (ASA) is a thermoplastic elastomer with properties similar to those of acrylonitrile butadiene styrene (ABS) but which offers improved weathering resistance. This type of copolymer has excellent resistance to UV irradiation, heat, moisture, and stress cracking and probably has the best weathering resistance of all acrylonitrile elastomers. It is extensively used in the building & construction, appliance, automotive, electrical/electronics, and sports goods industries.
Acrylonitrile butadiene styrene terpolymer (ABS) is an opaque low cost thermoplastic that has high stress and impact resistance and higher tensile strength than polystyrene and polyacrylonitrile itself. The butadiene portion provides flexibility and high impact resistance whereas the styrene-acrylonitrile portion provides strength, good dimensional stability, and creep and heat resistance. ABS is extensively used for toys including Lego and Kre-O bricks. Other important uses include housings for consumer electronics and small appliances, automotive consoles and panels, lamp and mirror housings, electronic plugs, wiring devices, keyboards as well as computer and printer housings.
Activation (Initiation) is a chemical process that starts a polymerization process. Compounds used as activators (initiators) are typically added in (very) small quantities. They are commonly used in the polymerization of vinyl monomers including acrylates, styrene, unsaturated polyester resins and elastomer formulations. They are also employed in adhesive systems to activate cure just before bonding.
Addition polymerization is any polymerization process that produces polymers without (low molecular) side products. The terms addition and chain polymerization are often used synonymously because most addition polymers are produced by chain polymerizations. However, a step-growth polymerization that produces polymers without elimination of a small molecule is also a form of addition polymerization.
Alkyd Resins are thermoplastic or thermosetting polyester resin compositions. They are known for their good weathering properties and are important ingredients in many synthetic paints due to their versatility and low cost. They are commonly produced by polycondensation of an alcohol (polyol) and a dicarboxylic acid or its anhydride.
Aramid Fibers are extremely resilient and heat-resistant synthetic fibers in which the fiber-forming substance is a long-chain synthetic polyamide. The fiber is produced by spinning a solid fiber from a liquid chemical blend. Aramid fibers have excellent heat resistance, very low flammability, and good chemical resistance to most organic solvents. They also have outstanding mechanical properties including a high strength-to-weight ratio, excellent dimensional stability, and outstanding abrasion resistance and tenacity (difficult to cut or fray).