WordNet

having the property of softening or fusing when heated and of hardening and becoming rigid again when cooled; "thermoplastic materials can be remelted and cooled time after time without undergoing any appreciable chemical change"
a material that softens when heated and hardens again when cooled (同)thermoplastic resin

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熱可塑形の / 熱可塑性物質(合成樹脂)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/10/28 14:54:49」(JST)

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A thermoplastic, or thermosoftening plastic, is a polymer that becomes pliable or moldable above a specific temperature, and returns to a solid state upon cooling.^[1]^[2] Most thermoplastics have a high molecular weight. The polymer chains associate through intermolecular forces, which permits thermoplastics to be remolded because the intermolecular interactions increase upon cooling and restore the bulk properties. In this way, thermoplastics differ from thermosetting polymers, which form irreversible chemical bonds during the curing process. Thermosets often do not melt, but break down and do not reform upon cooling.

Stress strain graph of thermoplastic material.

Above it's glass transition temperature, T_g, and below its melting point, T_m, the physical properties of a thermoplastic change drastically without an associated phase change. Within this temperature range, most thermoplastics are rubbery due to alternating rigid crystalline and elastic amorphous regions, approximating random coils.^{[citation needed]}

Some thermoplastics do not fully crystallize above glass transition temperature T_g, retaining some, or all of their amorphous characteristics. Amorphous and semi-amorphous plastics are used when high optical clarity is necessary, as a light wave cannot pass through smaller crystallites than its wavelength. Amorphous and semi-amorphous plastics are less resistant to chemical attack and environmental stress cracking because they lack a crystalline structure.

Brittleness can be lowered with the addition of plasticizers, which interfere with crystallization to effectively lower T_g. Modification of the polymer through copolymerization or through the addition of non-reactive side chains to monomers before polymerization can also lower T_g. Before these techniques were employed, plastic automobile parts would often crack when exposed to cold temperatures. Recently, thermoplastic elastomers have become available.^{[citation needed]}

Acrylic[edit]

Acrylic, a polymer called poly(methyl methacrylate) (PMMA), is also known by trade names such as Lucite, Perspex and Plexiglas. It serves as a sturdy substitute for glass for such items as aquariums, motorcycle helmet visors, aircraft windows, viewing ports of submersibles, and lenses of exterior lights of automobiles. It is extensively used to make signs, including lettering and logos. In medicine, it is used in bone cement and to replace eye lenses. Acrylic paint consists of PMMA particles suspended in water.

Nylon[edit]

Nylon, belonging to a class of polymers called polyamides, has served as a substitute for silk in products such as parachutes, flak vests and women's stockings. Its fibers are useful in making fabrics, rope, carpets and musical strings. In bulk form, nylon is used for mechanical parts including machine screws, gear wheels and power tool casings. In addition, nylon is used in the manufacture of heat-resistant composite materials.

Polyethylene[edit]

Polyethylene (or polyethene, polythene, PE) is a family of similar materials categorized according to their density and molecular structure. For example, ultra-high molecular weight polyethylene (UHMWPE) is tough and resistant to chemicals, and it is used to manufacture moving machine parts, bearings, gears, artificial joints and some bulletproof vests. High-density polyethylene (HDPE), recyclable plastic no. 2, is commonly used as milk jugs, liquid laundry detergent bottles, outdoor furniture, margarine tubs, portable gasoline cans, water drainage pipes, and grocery bags. Medium-density polyethylene (MDPE) is used for packaging film, sacks and gas pipes and fittings. Low-density polyethylene (LDPE) is softer and flexible and is used in the manufacture of squeeze bottles, milk jug caps, retail store bags. and (LLDPE) as stretch wrap in transporting and handling boxes of durable goods, and as the common household food covering. XLPE or "PEX" (cross-linked polyethylene) is a semi-rigid/flexible material which has gained wide use in cold or hot water building heating/cooling applications (hydronic heating and cooling) due to its exceptional resistance to breakdown from wide temperature variations.

Polypropylene[edit]

Polypropylene (PP) is useful for such diverse products as reusable plastic food containers i.e.) "microwave and dishwasher safe" plastic containers, diaper lining, sanitary pad lining and casing, ropes, carpets, plastic moldings, piping systems, car batteries, insulation for electrical cables and filters for gases and liquids. In medicine, it is used in hernia treatment and to make heat-resistant medical equipment. Polypropylene sheets are used for stationery folders and packaging and clear storage bins. Polypropylene is defined by the recyclable plastic number 5. Although relatively inert, it is vulnerable to ultraviolet radiation and can degrade considerably in direct sunlight. It may be worthy to note that (PP) is not as impact-resistant as the polyethlenes (HDPE, LDPE). PP is also somewhat permeable to highly volatile gases and liquids.

Polystyrene[edit]

Polystyrene is manufactured in various forms that have differing applications. Extruded polystyrene (PS) is used in the manufacture of disposable cutlery, CD and DVD cases, plastic models of cars and boats, and smoke detector housings. Expanded polystyrene foam (EPS) is used in making insulation and packaging materials, such as the "peanuts" and molded foam used to cushion fragile products. Extruded polystyrene foam (XPS), known by the trade name Styrofoam, is used to make architectural models and drinking cups for heated beverages. Polystyrene copolymers are used in the manufacture of toys and product casings.

Polyvinyl chloride[edit]

Polyvinyl chloride (PVC) is a tough, lightweight material that is resistant to acids and bases. Much of it is used by the construction industry, such as for vinyl siding, drainpipes, gutters and roofing sheets. It is also converted to flexible forms with the addition of plasticizers, thereby making it useful for items such as hoses, tubing, electrical insulation, coats, jackets and upholstery. Flexible PVC is also used in inflatable products, such as water beds and pool toys.

Teflon[edit]

Teflon is the brand name given by DuPont Corp. for a polymer called polytetrafluoroethylene (PTFE), which belongs to a class of thermoplastics known as fluoropolymers. It is famous as a coating for non-stick cookware. Being chemically inert, it is used in making containers and pipes that come in contact with reactive chemicals. It is also used as a lubricant to reduce wear from friction between sliding parts, such as gears, bearings and bushings.

References[edit]

^ http://www.lgschemistry.org.uk/PDF/Thermosoftening_and_thermosetting_plastics.pdf
^ Baeurle SA, Hotta A, Gusev AA (2006). "On the glassy state of multiphase and pure polymer materials". Polymer 47: 6243–6253. doi:10.1016/j.polymer.2006.05.076.

English Journal

Rheological Properties and Tunable Thermoplasticity of Phenolic Rich Fraction of Pyrolysis Bio-Oil.

Sahaf A, Laborie MP, Englund K, Garcia-Perez M, McDonald AG.SourceComposite Materials and Engineering Center and ∥Biological Systems Engineering, Washington State University , Pullman, Washington 99164, United States.
Biomacromolecules.Biomacromolecules.2013 Mar 4. [Epub ahead of print]
In this work we report on the preparation, characterization, and properties of a thermally treated lignin-derived, phenolic-rich fraction (PRF) of wood pyrolysis bio-oil obtained by ethyl acetate extraction. The PRF was characterized for viscoelastic and rheological behavior using dynamic mechanical
PMID 23424996

Thermoplasticity in the plant circadian clock: how plants tell the time-perature.

James AB, Syed NH, Brown JW, Nimmo HG.SourceInstitute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland. Allan.James@glasgow.ac.uk
Plant signaling & behavior.Plant Signal Behav.2012 Oct 1;7(10):1219-23. doi: 10.4161/psb.21491. Epub 2012 Aug 20.
In the March 2012 issue of The Plant Cell we describe extensive alternative splicing (AS) of Arabidopsis circadian clock genes. Notably these distinct post-transcriptional events associate with different steady-state temperatures and also with plants undergoing temperature transitions leading us to
PMID 22902701

Innovations in endodontic filling materials: guttapercha vs Resilon.

de Souza Filho FJ, Gallina G, Gallottini L, Russo R, Cumbo EM.SourcePiracicaba Dental School, University of Campinas, Sao Paulo, Brazil. franciscosouzafilho@yahoo.com.br
Current pharmaceutical design.Curr Pharm Des.2012;18(34):5553-8.
One of the goals of endodontic treatment is to achieve a complete, tridimensional, hermetic sealing of the root canal system to prevent the entry of microorganisms or their products through both the coronal and apical pathways. Gutta-percha is the most widely used material for root canal filling and
PMID 22632398

Japanese Journal

熱可塑性を利用したCF/PA6積層板の衝撃損傷修復と残留圧縮強度の実験的評価

金崎真人,内城千翔,田中基嗣 [他]
日本複合材料学会誌 40(3), 106-117, 2014
NAID 40020112247

No.16 ハイパーコール抽出溶剤の検討(3):石炭抽出促進成分とその循環性

堺康爾,宍戸貴洋,吉田拓也,奥山憲幸,演口眞基,菊池直樹
石炭科学会議発表論文集 (50), 32-33, 2013-10-21
… HPC has excellent thermoplasticity and large potential for coke additive to make a strong coke. …
NAID 110009725915

No.8 粘結材添加がコークス原料炭の軟化溶融挙動に及ぼす影響

熊谷治夫,宍戸貴洋,堺康爾,奥山憲幸
石炭科学会議発表論文集 (50), 16-17, 2013-10-21
Thermoplastic properties of coal and coal with "High Performance Coking additive, HPC" are investigated by means of ^1H-NMR relaxation measurement from the viewpoints of molecular mobility. High tempe …
NAID 110009725907