Polyethylene Chemical Properties
- Melting point:92 °C
- Boiling point:48-110 °C(Press: 9 Torr)
- Density 0.962 g/mL at 25 °C
- Flash point:270 °C
- storage temp. ?20°C
- form powder
- color White
- Specific Gravity0.95
- Water Solubility Soluble in acetone and benzene. Insoluble in water.
- Merck 14,7567
- Stability:Stable, but breaks down slowly in uv light or sunlight. Incompatible with halogens, strong oxidizing agents, benzene, petroleum ether, aromatic and chlorinated hydrocarbons, lubricating oils.
- NIST Chemistry ReferencePolyethylene(9002-88-4)
- EPA Substance Registry SystemPolyethylene (9002-88-4)
Polyethylene Usage And Synthesis
- Chemical Propertiessolid; appearance depends upon method of forming;
- Chemical PropertiesChemical and physical properties are markedly affected by
increasing density, which is affected by the shape and spacing
of the molecular chain. Low-density materials have highly
branched and widely spaced chains, whereas high-density
materials have comparatively straight and closely aligned
chains. Low-density polyethylene (0.926–0.9409 g/cm3) is
soluble in organic solvents at temperatures higher than
200°F. It is insoluble at room temperature. High-density
polyethylene (0.041–0.965 g/cm3) is hydrophobic, permeable
to gas, and has high electrical resistivity.
Low molecular weight polyethylenes have excellent electrical resistance and resistance to water and to most chemicals. Medium molecular weight polymers are waxes miscible with paraffin wax, and polyethylene polymers whose molecular weights are higher than 10,000 are the familiar tough and strong resins that are flexible or stiff. By varying the catalyst and methods of polymerization, properties such as density, crystallinity, molecular weight, and polydispersity can be regulated over wide ranges. Polymers with densities ranging from approximately 0.910 to 0.925 g/cm3 are low-density polyethylenes; those with densities ranging from 0.926 to 0.940 g/cm3 are medium-density polyethylenes; and those with densities ranging from 0.941 to 0.965 g/cm3 and higher are high-density polyethylenes. As the crystallinity or density increases, the products generally become stiffer and stronger and have a high softening temperature and high resistance to penetration by liquids and gases. At the same time, they lose some of their resistance to tear and environmental stress cracking.
High-density PE (HDPE) is a chemically pure, porous plastic implant material that can perform supportive functions. The material has good tissue biocompatibility and permits ingrowth of connective tissue with related vascularization. The material is being used more frequently in nasal surgery.
Polyethylene can be cross-linked by irradiation (electron beam, gamma, or X radiation) or by free radical catalysts such as peroxides.
- UsesPolyethylene (PE) is a thermoplastic polymer consisting of long hydrocarbon chains. PE is used in a number of applications including flexible film packaging produced by the blown film process. Polyethylene is used to regulate viscosity, suspension properties, and general stability in cosmetic formulations.
- UsesInjection and blow molded toys, housewares and lids.
- UsesInjection molded car seats, mower parts and pails.
- UsesHot melt coating for paper, additive in cast moldings, candles, oil-based inks and hot melt adhesives.
- UsesTypical applications included specialty injection molded parts.
- UsesAdditive to unsaturated polyesters, epoxides and other polymers to impart the unique properties of UHMWPE. Used in industrial parts, coatings and wear surfaces at 10-40 wt. %.
- UsesInjection molded, thin-walled containers and housewares.
- UsesFilm applications having good drawdown and toughness.
- UsesMold release additive, lubricant in rubber processing, extrusion and calendering aid for PVC and dispersing aid for color concentrates.
- UsesBearings, gears, bushings and other moving parts.
- UsesLaboratory tubing; in making prostheses; electrical insulation; packaging materials; kitchenware; tank and pipe linings; paper coatings; textile stiffeners.
- Usespolyethylene is used to regulate viscosity, suspension properties, and general stability in cosmetic formulations. It is derived from petroleum gas or dehydration of alcohol.
- Definitionpolyethylene: A flexible waxy translucentpolyalkene thermoplastic made in avariety of ways producing a polymerof varying characteristics. In the ICIprocess, ethene containing a trace of oxygen is subjected to a pressure inexcess of 1500 atmospheres and atemperature of 200°C. Low-densitypolyethene (r.d. 0.92) has a formulaweight between 50 000 and 300 000,softening at a temperature around110°C, while the high-density polythene(r.d. 0.945–0.96) has a formulaweight up to 3 000 000, softeningaround 130°C. The low-density polymeris less crystalline, being more atactic.Polyethene is used as aninsulator; it is acid resistant and iseasily moulded and blown.
- DefinitionChEBI: A polymer composed of ethane units.
- Production MethodsLinear PE is produced by a low-pressure solution or gasphase
process that is initiated by a variety of transition metal
catalysts. The most common catalysts are Ziegler titanium
compounds with aluminum alkyls and Phillips chromium
oxide-based catalysts. The gas-phase and slurry processes
are used to produce high molecular weight, high-density
(HMW-HDPE) products. The highest density linear PEs can
be made from an α-olefin comonomer, typically octene for the solution process and butene or hexene for the gas-phase
process. Linear PE does not have long-chain branches and is
therefore more crystalline. The short-chain branches found in
linear PE serve as tie molecules, which give the higher
α -olefin copolymers improved puncture and tear properties.
Included in the linear PE family are ultra-low-density PE
(ULDPE), LLDPE, and HDPE.
HDPE’s main use is in blow-molded products such as milk bottles, packaging containers, drums, car fuel tanks, toys, and houseware. Film and sheet are widely used in wrappings, refuse sacks, carrier bags, and industrial liners. Injection molding products include crates, pallets, packaging containers, houseware, and toys. Extrusion grades are used in pipes, conduit, wire coating, and cable insulation.
LLDPE is a thermoplastic that in many applications replaces its predecessor, low-density polyethylene (LDPE), or is used in blends with LDPE. In particular, LDPE’s shortchain branching gives it higher tensile strength, puncture, and anti-tear properties, making it especially suitable for film applications.
- Agricultural UsesLDPE is short for low density polyethylene. LDPE sheets are used for lining jute bags in which fertilizers are stored. LDPE acts as a waterproofing material.
- Industrial usesRigidity and tensile strength of the HDPE resins are considerably higher than those properties in the low- and medium-density materials. Impact strength is slightly lower, as is to be expected in a stiffer material, but values are high, especially at low temperatures, compared with those of many other thermoplastics.
HDPE resins are available with broad, intermediate, and narrow molecular-weight distribution, which provides a selection to meet specific performance requirements. As with the other polyethylene grades, very-high-molecular- weight copolymers of HDPE resins are available with improved resistance to stress cracking.
Applications of HDPE range from film products to large, blow-molded industrial containers. The largest market area is in blowmolded containers for packaging milk, fruit juices, water, detergents, and household and industrial liquid products. Other major uses include high-quality, injection-molded housewares, industrial pails, food containers, and tote boxes; extruded water and gas-distribution pipe, and wire insulation; and structural-foam housings.
HDPE resins are also used to rotationally mold large, complex-shaped products such as fuel tanks, trash containers, dump carts, pallets, agricultural tanks, highway barriers, and water and waste tanks for recreational vehicles.
- Industrial usesLDPE, the first of the polyethylenes to be developed, has good toughness, flexibility, low-temperature impact resistance, clarity in film form, and relatively low heat resistance. Like the higher-density grades, LDPE has good resistance to chemical attack.
One of the fastest-growing plastics is linear LLDPE, used mainly in film applications but also suitable for injection, rotational, and blow molding. Properties of LLDPE are different from those of conventional LDPE and HDPE in that impact, tear, and heat-seal strengths and environmental stress-crack resistance of LLDPE are significantly higher. Major uses at present are grocery bags, industrial trash bags, liners, and heavy-duty shipping bags for such products as plastic resin pellets.
- Industrial usesPolyethylene thermoplastic resins include lowdensity polyethylenes (LDPE), linear low-density polyethylenes (LLDPE), high-density polyethylenes (HDPE), and ethylene copolymers, such as ethylene-vinyl acetate (EVA) and ethylene- ethyl acrylate (EEA), and ultrahighmolecular- weight polyethylenes (UHMWPE). The basic properties of polyethylenes can be modified with a broad range of fillers, reinforcements, and chemical modifiers, such as thermal stabilizers, colorants, flame retardants, and blowing agents. Major application areas for polyethylenes are packaging, industrial containers, automotive, materials handling, consumer products, medical products, wire and cable insulation, furniture, housewares, toys, and novelties.
Polyethylene is a water-repellent, white, tough, leathery, thermoplastic resin very similar in appearance to paraffin wax. Properties vary from a viscous liquid at low molecular weights to a hard waxlike substance at high molecular weights. It is used as a coating for glass bottles and fiberglass fabrics (special treatments for glass are required to obtain good adhesion between polyethylene and glass) and is also used as an injection-molding material for ceramics.
TIn the polymerization process, the double bond connecting the carbon atoms is broken. Under the right conditions, these bonds reform with other ethylene molecules to form long molecular chains. Ethylene copolymers, EVA, and EEA are made by the polymerization of ethylene units with randomly distributed comonomer groups, such as vinyl acetate (VA) and ethyl acrylate (EA).
- Safety ProfileQuestionable carcinogen with experimental tumorigenic data by implant. Reacts violently with F2. When heated to decomposition it emits acrid smoke and irritating fumes.
- CarcinogenicityIARC reports that data available do not allow the evaluation of carcinogenicity of ethylene in humans. Rats exposed to ethylene by inhalation show no increase in tumor incidence.
- Purification MethodsCrystallise it from thiophen-free *benzene and dry it over P2O5 under vacuum.
Polyethylene Preparation Products And Raw materials
- Preparation Products3-Chloroperoxybenzoic acidAcetyl ketenePoly(ethylene glycol)Tetrabutylammonium fluoridepolyethylene conductive plasticsPigment Yellow 12 polypyrrole-polyvinyl chloride composite filmMaster-batchesribonucleic acid for injectionUV-photoxidation degradation film containing FeDBC photosensitizeconductive filmPOLY(VINYL ACETATE)lithium-ion batteryDilauroyl peroxidesoftener PEGPOLYETHYLENE, CHLORINATEDPlastic productspolyethersulfone ultrafiltration membranedetergent 801one-component moist curing PU sealantpolyacrylamide emulsifierhigh-temperature leveling agent FZ-802water proofing agent RSICyanuric fluoridepolyphenylacetyleneEthylene-vinyl acetate copolymer latexMaster batch,antistaticPolyethylene plastic rodrepeelable pressure sensitive adhesive PT-02
- Raw materialsPROPYLENEPropionaldehydePROPANE
- Polypropylene Poly(vinyl alcohol) 1,2-Dibromoethane LDPE hot melt adhesive powder O-METHYL-O'-[2-(SUCCINYLAMINO)-ETHYL]POLYETHYLENE GLYCOL 2,000 N-SUCCINIMIDYL ESTER,O-METHYL-O'-[(N-SUCCINIMIDYL)SUCCINYL-AMINOETHYL]POLYETHYLENE GLYCOL 2,000 O-(2-AMINOETHYL)-O'-[2-(BOC-AMINO)ETHYL]POLYETHYLENE GLYCOL 10000,O-(2-AMINOETHYL)-O'-[2-(BOC-AMINO)ETHYL]POLYETHYLENE GLYCOL 5000 SCRAPER HARD RED HDPE BLADE 5 W X 6IN& WIDE-MOUTH WASH BOTTLES LDPE 1000ML BURETTE CLAMP DOUBLE HDPE WASH BOTTLE, LDPE, WIDE MOUTH WITH VALVE, 500ML, LABELLED "ETHANOL" (5EA) Ethylene glycol Polyethylene ETHYLENE DIACRYLATE Polyvinyl chloride Polyvinylpyrrolidone Ethylene carbonate ETHYLENE OXIDE ETHYLENE
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