Thermoplastics

Thermoplastics include various varieties of
polymers which properties and processes
are detailed below.

Vinyl polychloride is the polymerization of vinyl chloride, itself obtained by action of chlorine on ethylene. PVC-C is over chlorinated PVC with improved thermal behaviour. Discovered in 1931, it can be either rigid or flexible according to incorporated ingredients. That's, after the EP, the more used plastic in the world. It's self-extinguishing. Applications: bottles, kitchen utensils, sheets, cables, plates, pipes, thin films, bags, gutters, shutters, fabrics impregnated for furnishing, building or civil engineering...

Polyethylene is the polymerization of a gas, the ethylene itself obtained by pyrolysis of ethane. Since the discovery of Radically Low Density Polyethylene (RLDPE) in 1939, the family of the PE did not cease extending : High density (HDPE), Linear Low density (LLDPE). Strong point: excellent dielectric characteristics. Discovered fortuitously in England by ICI, they are used to insulate the first underwater telephone cable connecting Europe to the United States. Very insulating, these materials allowed the development of the radar and the famous Tupperware®. Nowadays, polyethylene with low density is used as films for packing, agriculture, building and dustbin bags. For polyethylene with high density, it is used for manufacture of gasoline tanks, bags, bottles, urban dustbins and winsurf. Polyethylenes are the most used plastics in the world. Applications: cable-making, hollow body, kitchen utensils, sheets, pipes, thin films, bags, foams...

Polypropylene is the thermoplastic which has the strongest rate of development. It's obtained by polymerization of a gas, the propylene. Discovered in 1957, this product always had a very strong growth. Strong points: high rigidity, resistance to cracking, good transparency and brilliance of surface. Applications: food packing, technical parts for car (bumper, batteries...), crockery for microwave furnaces, carpets, cords...

Polystyrene is obtained by polymerization of styrene, itself obtained by action of benzene on ethylene. This family of plastics includes polystyrene, polystyrene shock and expanded polystyrene. It's possible to manufacture objects with focused and detailed shape, with sharp angles, but their chemical, thermal and mechanical resistances are low; polystyrene shock having nevertheless improved mechanical properties. Polystyrene was discovered in 1930 and expansible polystyrene in 1951. Applications: polystyrene and polystyrene shock are used for disposable products: crockery, utensils for foodstuffs... but also in domestic appliances, audio-visual and toys. The expanded polystyrene, white and rigid foams, is often used for heat insulation in building and packing and also for shock protection. It is also used for realisation of television and film settings.

Polyamides are obtained starting from an acid dicarboxylic and a diamine or from an amino acid. According to chains length, various types of Pa can be obtained. It's the first polymer considered as a technical plastic that has been discovered (1938). There are very numerous type of Pa which are distinguished by abbreviations : PA6,6 (Nylon®) - PA11 (Rilsan®) - PA12 - PA46 (overdraft in 1988)... Applications: technical parts for industry (gears...), the car, pipes, textiles, carpets, corrosion resistant coatings.

Polycarbonate is obtained from bisphenol A and phosgene. Discovered in 1957, it's a technical plastic extremely resistant to shocks and heat. Applications : bullet proof glass, safety caps and protection, standard lamps, indicators and rear lights of vehicles, technical parts...

Polyesters are obtained by reaction of diméthyltéréphtalate with ethylene glycol or butylene glycol. There are 2 types of thermoplastic polyesters : the poly (ethylene glycol terephthalate) and the poly (butylene glycol terephthalate). In 1941, Dickson and Whinfield discovered the polymer. Then in 1950-1955, the manufacture of Bi-directed films (Mylar®), textile fibres (Dacron®, Tergal®, Terylène®) are developped. Then in 1970, the polymer is used as a technical material. Finally in 1975, the first hollow products in P.E.T.P. bi-directional stretched are manufactured. Applications: PET is especially employed for manufacture of textile wire, films and bottles, PBT is used in reinforced glass fiber forms for manufacture of many technical parts (car, household, electrical engineering).

Polyacetals are the first engineering plastics which have metal behaviors like steel, aluminium, zinc... This polymer is obtained from polymerization of formaldehyde. Discovered in 1953, polyacetals are derived from formaldehyde. They include 2 products: the homopolymer of formaldehyde (polyoxymethylene) and the copolymer of trioxane and ethylene oxide. Applications: parts with strong mechanical requirements (gears, rollers, pulleys), bottles of cosmetics.

Fluoropolymers are obtained by polymerization under high pressure of tetrafluoroethylene (for PTFE), generally in aqueous medium. Discovered in 1943 these polymers have exceptional behaviors (thermal, chemical, fire resistance) because of substitution by fluorine of hydrogen atoms in macromolecule. Principal types are PTFE (polytetrafluorethylene) the PCTFE (polychlorotrifluorethylene) and the PVDF (vinylidene polyfluoride). Applications: antiblocking coatings of kitchen utensiles, anti-stains and anti-anti-graffiti, pipings, sleeving of cables, joints, membranes, coatings technical for industry...

Phenylene polysulphide is manufactured starting from paradichlorobenzene and sodium sulphide. Polysulphone is produced starting from sulfone aromatic bi-chlorinated and disodic salt of bisphenol A. Polysulphone is launched in 1966 and the phenylene polysulphide in 1973. Applications: their principal applications relate to electronics, parts for aviation, aerospace or automotive. But also coatings on metals and realisation of surgical material.

Polyphenylene ether is manufactured by phenol coupling oxidizing. Used primarily in high technology, it has a great mechanical resistance. Applications: technical parts for automotive, electricity, electric household appliances...

Polymethylmethacrylate (PMMA) results from polymerization of methyl ester of methacrylic acid. Discovered in 1927, this polymer, more known under the marks " Altuglas® " or " Plexiglas® ", has an exceptional transparency. Applications: bath-tubs, lamp-shade, glazings, small movable, watch glasses, lenses, rear lights vehicles, signs...

Styrenic ABS and SAN are obtained by polymerization of styrene itself obtained by action of benzene on ethylene. SAN is a copolymer styrene-acrylonitrile. ABS is a copolymer SAN in which a butadiene latex is dispersed, which confers an improved behaviour against shocks. Tripolymer acrylonitrile-butadiene-styrene (ABS) was discovered in 1946. SAN has good behaviour against hydrocarbons. Applications for styrenic ABS : casings of apparatuses, toys, electric household appliances, car... for the styrenic SAN: electric household appliances, electrical engineering...

Thermoplastic polyurethans are an alternative of polyurethans which are in general thermohardening (reticulated). Thermoplastic polyurethans (TPU) are obtained in linear chains by reaction of diisocyanate with polyester or polyol bifunctional. Lengthening of polyol or polyester chain brings flexibility and makes possible to produce thermoplastic elastomers. Applications : these products are implemented like any thermoplastic, by injection, extrusion, calendering... for TPU, or by run reactive liquids (CPU). Applied in solution, they allow coating of textiles in order to make them tight. They are used to make gears, wheels of roller skates, driving belts, ski boots, industrial or sporting floor coverings...

Aromatic thermoplastic polymers are numerous : PAI - imid polyamide, PEEK - polyetheretherketone, PEK - polyetherketone, PSU - polysulphone, PESU - polyethersulfone, PPSU - polyphenylensulfone, PPP - aromatic polyamide, PEI - polyetherimide... Applications: they all are characterized by a better temperature stability, due to presence of an aromatic nucleus. Their temperature of use can thus reach 150 to more than 200°C. Their resistance to oils and hydrocarbons is good to very good. They are especially employed for the manufacture of technical or electric parts, for mechanical engineering industry, household electricals, automotive, aeronautics, and for medical sterilizable devices.