Polytrimethylene terephthalate (PTT), is a

polyester Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natural ...

synthesized and patented in 1941. It is produced by a method called

condensation polymerization In polymer chemistry, condensation polymers are any kind of polymers whose process of polymerization involves a condensation reaction (i.e. a small molecule, such as water or methanol, is produced as a byproduct). Condensation polymers are form ...

or transesterification. The two

monomer In chemistry, a monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization. Classification Mo ...

units used in producing this polymer are: 1,3-propanediol and

terephthalic acid Terephthalic acid is an organic compound with formula C6H4(CO2H)2. This white solid is a commodity chemical, used principally as a precursor to the polyester PET, used to make clothing and plastic bottles. Several million tonnes are produced annua ...

or dimethyl terephthalate. Similar to

polyethylene terephthalate Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods ...

, the PTT is used to make

carpet A carpet is a textile floor covering typically consisting of an upper layer of pile attached to a backing. The pile was traditionally made from wool, but since the 20th century synthetic fibers such as polypropylene, nylon, or polyester hav ...

fibers. PTT's value as a commercial polymer has improved due to more economical and efficient methods to produce 1,3-propanediol in the 1980s by Degussa, via

acrolein Acrolein (systematic name: propenal) is the simplest unsaturated aldehyde. It is a colorless liquid with a piercing, acrid smell. The smell of burnt fat (as when cooking oil is heated to its smoke point) is caused by glycerol in the burning fa ...

, and Shell via the hydroformylation of ethylene oxide.

DuPont DuPont de Nemours, Inc., commonly shortened to DuPont, is an American multinational chemical company first formed in 1802 by French-American chemist and industrialist Éleuthère Irénée du Pont de Nemours. The company played a major role in ...

has successfully commercialized the production of this polymer via 1,3-propanediol obtained by fermentation. These developments may allow PTT to effectively compete against PBT and PET, two polyesters that have been far more successful than PTT to date.

Production

Similar to the ubiquitous

poly(ethylene terephthalate) Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in synthetic fibre, fibres for clothing, packaging, conta ...

, this polymer is prepared by the esterification of 1,3-propanediol (HO(CH₂)₃OH) with

(C₆H₄(COOH)₂), or by transesterification of dimethyl terephthalate: This polymer has been commercialized as Sorona by

Applications

On Friday, March 20, 2009, the Federal Trade Commission approved a subclass to polyester called triexta. The PTT fiber used in Mohawk's SmartStrand carpet, and branded Sorona by Dupont can be labeled triexta. Triexta has been reported to have several advantages over polyethylene terephthalate, including better stain resistance and softness.{{Cite web , title=Triexta PTT Carpet Fiber , last=Simmons , first=Cheryl , work=The Spruce , date=8 August 2019 , url= https://www.thespruce.com/triexta-ptt-carpet-fiber-2908799 The FTC had last approved an extension for residential carpet in 1959. Mohawk Industries and DuPont applied jointly for FTC approval of the triexta polyester subclass in 2006; it was approved three years later.

References

External links

Forensic Science Communications literature review of Polytrimethylene terephthalate
Polyesters Plastics Terephthalate esters