Polyester is a category of polymer containing an ester functional group in the main chain. As a special ingredient, it most often refers to a type called polyethylene terephthalate (PET). Polyesters include natural chemicals, such as in cuticle cuticle plants, as well as synthetics such as polybutir. Natural polyesters and some of which are synthetic are biodegradable, but most synthetic polyesters do not. This material is widely used in clothing.
Depending on the chemical structure, the polyester may be thermoplastic or thermoset. There are also polyester resins healed by hardener; however, the most common polyester is thermoplastic.
Fabrically woven or knitted fabrics of polyester yarns or threads are widely used in garments and home furnishings, from shirts and pants to jackets and hats, sheets, blankets, upholstered furniture and computer mouse mats. Industrial polyester fibers, yarns and ropes are used for automobile tires, cloth for conveyor belts, seat belts, upholstered fabrics and plastic reinforcements with high energy absorption. Polyester fibers are used as bearings and insulating materials on cushions, blankets and padding pads. The polyester fabrics are very stain resistant - in fact, the only coloring class that can be used to change the color of the polyester fabric is what is known as dispersion dye.
Polyester fibers are sometimes spun along with natural fibers to produce a fabric with a mixed nature. The cotton-polyester (polycotton) mixture can be strong, wrinkle and tear-resistant, and reduce shrinkage. Synthetic fibers using polyester have high water, wind and environmental resistance compared to plant-derived fibers. They are less fire resistant and can melt when ignited.
The polyester blends have been renamed so as to suggest the similarity or even their superiority to natural fibers (eg, Chinese silk, which is a term in the textile industry for 100% woven polyester fibers woven like sheen and insect silk resilience).
Polyester is also used for making bottles, films, tarpaulins, canoes, liquid crystal displays, holograms, filters, dielectric films for capacitors, insulating film for wire and insulation tape. Polyester is widely used as finishing on high quality wood products such as guitar, piano and vehicle interior/yacht. The thixotropic properties of spray-applicable polyesters make them ideal for use in open grain wood, as they can quickly fill the wood grain, with high film thickness per building. The healed polyester can be sanded and polished to a high end result and durable.
Liquid crystal polyester is one of the first industrial liquid crystal polymers used. They are used for mechanical properties and heat resistance. These characteristics are also important in their application as sealable jet engines.
Video Polyester
Jenis
The polyester as a thermoplastic may change shape after heat application. While flammable at high temperatures, polyesters tend to shrink from fire and extinguish themselves during ignition. The polyester fibers have high strength and E-modulus as well as low water absorption and minimal shrinkage compared to other industrial fibers.
Unsaturated polyester (UPR) is a thermosetting resin. They are used in a liquid state as a casting material, in a molding sheet compound, as a fiberglass laminated resin and a non-metallic auto-body filler. They are also used as thermoset polymer matrices in pre-pregs. Polyester unsaturated fiber-reinforced polyester finds extensive application in the body of a yacht and as a car body part.
According to their main chain composition, polyesters can be:
Increasing the aromatic parts of the polyester increases their glass transition temperature, melting temperature, thermal stability, chemical stability...
Polyesters can also be telechelic oligomers such as polycaprolactone diol (PCL) and polyethylene adipate diol (PEA). They are then used as a prepolymer.
Maps Polyester
Industry
Basics
Polyesters are synthetic polymers made of pure terephthalic acid (PTA) or dimethyl ester dimethyl terephthalate (DMT) and monoethylene glycol (MEG). With a market share of 18% of all plastic materials produced, it ranged third after polyethylene (33.5%) and polypropylene (19.5%).
The main raw materials are described as follows:
- Pure terephthalic acid (PTA) CAS-No.: 100-21-0
- Synonyms: 1.4 benzenedicarboxylic acid,
The sum formula: C 6 H 4 (COOH) 2 , mol. Weight: 166.13 - Dimethylterephthalate (DMT) CAS-No.: 120-61-6
- Synonyms: 1.4 benzenedicarboxylic acid dimethyl ester,
The sum formula: C 6 H 4 (COOCH 3 ) 2 , mole. Weight: 194.19 - Mono-ethylene glycol (MEG) CAS No: 107-21-1
- Synonyms: 1,2 ethanediol,
The sum formula: C 2 H 6 O 2 , mol. weight: 62.07
To make polymers of high molecular weight, a catalyst is required. The most common catalyst is antimony trioxide (or antimony tri-acetate):
- Antimony trioxide (ATO) CAS-No.: 1309-64-4
- mole. weight: 291.51,
The sum formula: Sb 2 O 3
In 2008, about 10,000 tons of Sb 2 O 3 were used to produce about 49 million tons of polyethylene terephthalate.
Polyester is described as follows:
- Polyethylene terephthalate CAS-No.: 25038-59-9
- Synonyms/abbreviations: polyester, PET, PES,
The sum formula: H- [C 10 H 8 O 4 ] - n = 60-120 OH, mol. unit weight: 192.17
There are several reasons for the importance of polyester:
- PTA or DMT and MEG raw materials are relatively easy to access
- The polyester chemical synthesis process is well understood and described
- Low toxicity level of all raw materials and by-products during polyester production and processing
- Possible to generate PET in closed loop at low emission to environment
- Extraordinary polyester mechanical and chemical properties
- Can be recycled
- Various intermediate and final products made of polyester.
In the following table, world polyester production estimates are shown. Its main applications are polyester textiles, polyester resin bottles, polyester films mainly for packaging and polyester specifically for engineering plastics. According to this table, the total world polyester production may exceed 50 million tonnes per year before 2010.
Manufacturers of raw materials
The raw materials of PTA, DMT and MEG are mainly produced by large chemical companies that are sometimes integrated into crude oil refineries where p -Xylene is the base material for producing PTA and liquefied petroleum gas (LPG ). ) is the base material for generating MEG.
Polyester Process
After the first phase of polymer production in the melting phase, the product stream is divided into two different application areas which are mainly textile applications and packaging applications. In the following table, the main application of textile and packing of polyester is listed.
Abbreviation:
- PSF
- Polyester-staple Fiber;
- POY
- Partially oriented threads;
- DTY
- Retracted textured thread;
- FDY
- Full drawn thread;
- CSD
- Soft drinks;
- A-PET
- Amorphous polyester film;
- BO-PET
- Polyester-oriented polyester film;
A comparable smaller market segment (less than 1 million tonnes/year) of polyester is used to produce engineering plastics and masterbatch.
To produce high melt polyester with high efficiency, high output processing steps such as staple fiber (50-300 ton/day per spin line) or POY/FDY (up to 600 ton/day divided into about 10 spinning machines) are Meanwhile more and more vertically integrated direct process. This means that the melting polymer is directly converted into fibers or filaments without the general step of pelletizing. We are talking about full vertical integration when polyesters are produced on one site ranging from crude oil or refining products in chain oil -> benzene -> PX -> PTA -> PET melt -> fibers/filaments or bottle-grade resins. The integrated process is temporarily shaped in more or less discontinuous processes at one production site. Eastman Chemicals was the first to introduce the idea of ​​closing chains from PX to PET resins with so-called INTEGREX processes. The capacity of vertically integrated production sites is & gt; 1,000 tons/day and can easily reach 2500 tons/day.
In addition to the large processing units mentioned above to produce fiber or staple yarn, there are ten thousand small and very small processing plants, so it can be estimated that the polyester is processed and recycled in more than 10,000 plants worldwide. This without counting all the companies involved in the supply industry, starting with engineering and processing machines and ending with special additives, stabilizers and colors. It is a gigantic industrial complex and still grows 4-8% annually, depending on the region of the world.
Synthesis
The synthesis of polyesters is generally achieved by polycondensation reactions. See "condensation reaction in polymer chemistry". The general equation for the reaction of diols with acids is:
- (n 1) R (OH) 2 n RÃ,Â' (COOH) 2 -> HO [ROOCRÃ,Â'COO] n ROH 2n H 2 O
Azeotrope esterification
In this classical method, alcohols and carboxylic acts react to form carboxylic esters. To assemble the polymer, the water formed by the reaction must be removed continuously with an azeotropic distillation.
Transesterification of alcohol
Acilation (HCl method)
The acid is started as hydrochloric acid, and thus the resulting polycondensation with hydrochloric acid emissions (HCl) is not water. This method can be done in solution or as enamel.
- Silil Method
- In this variant of the HCl method, the carboxylic acid is dried by trimethyl silyl ether from the alcohol component and the production of trimethyl silyl chloride is obtained
Methods of acetate (esterification)
- Silyl acetate method
Ring-opening polymerization
Aliphatic polyesters can be assembled from lactones in very light conditions, catalyzed anionically, cationically or metallurgically. A number of catalytic methods for copolymerization of epoxides with cyclic anhydrides have also recently been shown to provide a variety of both oxygenated and unsaturated difunctional polyesters.
Biodegradation
The futuro house is made of fiberglass reinforced polyester plastic; polyesters, polyurethanes, and poly (methylmethacrylate) one of which is found to be degrading by Cyanobacteria and Archaea.
Environmental issues
Pollution of freshwater and seawater habitats
A team at Plymouth University in the UK spent 12 months analyzing what happens when a number of synthetic materials are washed at different temperatures in a domestic washing machine, using different detergent combinations, to measure microfiber warehouses. They found that the average washing load of 6 kg can release about 137,951 fibers from the cotton-polyester blend fabrics, 496,030 fibers of polyester and 728,789 of acrylic. The fibers add to the common microbial pollution.
See also
- Polyamide
- Microfiber
- Oligoester
- Polyester resin
References
Further reading
- Textiles , by Sara Kadolph and Anna Langford. Issue 8, 1998.
External links
- Polyesterisation of lipase catalysis: Polymerization of Enzyme Catalysis from End-Functionalized Polymers in Microreactor
Source of the article : Wikipedia
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