What is poly (ethenol) alcohol?
Poly (ethenol) is also called polyvinyl alcohol or PVOH. It is sometimes called PVA but this also stands for poly (vinyl acetate) so it is best to use PVOH. Poly (ethenol) has the repeat unit shown below
How is polyethylene glycol made from ethylene oxide?
Polyethylene Glycol: Polyethylene glycol is produced from the reaction between ethylene oxide and water, ethylene glycol or ethylene glycol oligomers. Ethylene Glycol: The molecular weight of ethylene glycol is about 62.07 g/mol.
What does poly (ethenol)-PVOH stand for?
Polymers - Poly ( ethenol) - PVOH - Polyvinyl Alcohol. What is Poly ( ethenol )? Poly ( ethenol) is also called polyvinyl alcohol or PVOH. stands for poly ( vinyl acetate) so it is best to use PVOH.
What is polyethylene (PE)?
Polyethylene (PE) is a polymer of long chains derived from the monomer ethylene (IUPAC name " ethene "). It is one of the world’s most common plastics, with a wide range of uses and over 60 million tons produced worldwide every year.
What is polyvinyl alcohol used for?
PVA is used in sizing agents that give greater strength to textile yarns and make paper more resistant to oils and greases. It is also employed as a component of adhesives and emulsifiers, as a water-soluble protective film, and as a starting material for the preparation of other resins.
Is polyvinyl alcohol harmful?
PVA is approved safe by the FDA for food packaging, is considered a GRAS ingredient by the FDA, and has biomedical and pharmaceutical applications as well (1,2,3).
What is PVOH made of?
Polyvinyl alcohol or PVOH is a crystal clear, water soluble thermoplastic derived from polyvinyl acetate through partial or complete hydroxylation.
Is polyvinyl alcohol good for your skin?
Polyvinyl alcohol can cause skin irritation unless it is combined with other ingredients that protect the skin, such as emollients or skin-repairing ingredients.
Is poly vinyl alcohol plastic?
Polyvinyl alcohol (PVOH, sometimes also called PVA) is a synthetic polymer and plastic that is water soluble and biodegradable under both aerobic and anaerobic conditions.
Is polyvinyl alcohol real alcohol?
It's a chemistry wonder! Polyvinyl Alcohol (PVA, PVOH or PVAI) is a synthetic polymer. This means it's made up of many molecules strung together like a necklace.
Is PVOH and PVA the same?
Polyvinyl alcohol (PVOH, PVA, or PVAl) is a synthetic polymer which is both colourless, odourless and water-soluble. It was initially discovered in the early 1920's and since has been used in numerous applications from the lamination of safety glass to the packaging of laundry detergents.
Is polyvinyl alcohol PVOH plastic?
Yes. PVA stands for Polyvinyl Alcohol and is sometimes also written as PVOH. PVA is a synthetic plastic polymer that is often used to make thin layers of plastic wrapping and lining, like the wrapping of dishwasher and laundry pacs.
Is PVOH environmentally friendly?
Because of its chemical properties, polyvinyl alcohol is not biodegradable in nature; therefore, when it ends up in landfills, it does not break down into carbon dioxide and water.
Is polyvinyl alcohol good for sensitive skin?
The Bottom Line. Polyvinyl Alcohol is safe in small doses. But stay away from peel-off masks. In the high concentrations used here, it can be drying, irritating, and overall bad for skin.
Do all peel-off masks have alcohol?
I've noticed that quite a few peel-off masks also have alcohol, which is presumably there as a solvent or penetration enhancer. Obviously, the presence of alcohol - which again, on its own can be pretty drying and sensitizing to skin - just exacerbates any issues a peel-off mask might have.
What does alcohol denat do to your skin?
Using alcohol denat can cause flaking, irritation, and other complexion issues. While any skin type experiences breakouts, dry skin is at a particular risk. Not only is dry skin in a perpetual subtle state of irritation, but dead surface skin is more common and is very likely to clog pores.
What is PE in plastic?
Polyethylene (PE) is a polymer of long chains derived from the monomer ethylene (IUPAC name " ethene "). It is one of the world’s most common plastics, with a wide range of uses and over 60 million tons produced worldwide every year. Several different categories exist, based on density and branching.
What are geomembrane pipes made of?
For example, geomembranes are often made of HDPE and are widely used as liners for fish ponds, constructed wetlands and biogas digesters. Its resistance to degradation also warrants its use in the natural gas industry in transporting natural gas underground in high density PE pipes.
Is polyethylene a two step conversion?
Polyethylene from ethanol two step conversion. Ethene is a very simple two-carbon organic molecule (C 2 H 4) that does not have to be derived from petroleum. In fact, it can easily be produced from ethanol in a dehydration reaction. This has been known for many decades, but was not cost-competitive at low oil prices.
Is ethylene flammable?
Both ethanol and ethene are flammable, so be careful to ensure against vapor ignition. Initial runs should be done in small batch sizes to ensure greater safety. Ethanol is toxic to the liver but poisoning symptoms should be obvious. Ethylene gas is highly flammable and should be kept away from any source of sparks or static electricity. Technicians running this process should wear a lab coat, eye protection and gloves. A thermal and impact jacket will be a modular piece of the reactor design. A secondary firebrick jacket will be used for this application and can incorporate venting to prevent buildup of dangerous gases.
Is PE a petroleum product?
After distillation and purification in large, capital-intensive facilities, ethylene is produced. This is then polymerized to polyethylene, a process that again involves high temperatures, high pressures and often toxic organic solvents. Clearly not an ideal situation.
Is aluminum a catalyst for ethanol dehydration?
Aluminum is a favored catalyst for ethanol dehydration to ethylene but additional compounds such as transition metals increase yield and selectivity while other zeolite catalysts have also been described (Chen et al.). Polymerization of ethylene is an exothermic reaction with multiple generations of catalysts.
How much polyvinyl alcohol was consumed in 2006?
Worldwide consumption of polyvinyl alcohol was over one million metric tons in 2006. Large producers include Kuraray (Japan, Europe, and US) and Sekisui Specialty Chemicals (US), while mainland China has installed a number of very large production facilities in the past decade and currently accounts for 45% of world capacity.
How are polyvinyl acetals prepared?
Polyvinyl acetals are prepared by treating PVA with aldehydes. Butyraldehyde and formaldehyde afford polyvinyl butyral (PVB) and polyvinyl formal (PVF), respectively. Preparation of polyvinyl butyral is the largest use for polyvinyl alcohol in the U.S. and Western Europe.
Where is vinylon fiber made?
Its largest application in China is its use as a protective colloid to make polyvinyl acetate dispersions. In Japan its major use is the production of Vinylon fiber. This fiber is also manufactured in North Korea for self-sufficiency reasons, because no oil is required to produce it.
What is PVA in paper?
Poly (vinyl alcohol) ( PVOH, PVA, or PVAl) is a water - soluble synthetic polymer. It has the idealized formula [CH 2 CH (OH)] n. It is used in papermaking, textile warp sizing, as a thickener and emulsion stabilizer in PVAc adhesive formulations and a variety of coatings. It is colourless (white) and odorless.
Is PVA a polymer?
Unlike most vinyl polymers, PVA is not prepared by polymerization of the corresponding monomer as the monomer, vinyl alcohol, is thermodynamically unstable with respect to its tautomer acetaldehyde. Instead, PVA is prepared by hydrolysis of polyvinyl acetate, or sometimes other vinyl ester-derived polymers with formate or chloroacetate groups instead of acetate. The conversion of the polyvinyl esters is usually conducted by base-catalysed transesterification with ethanol:
What are the properties of polyethylene?
The particular material properties of "polyethylene" depend on its molecular structure. Molecular weight and crystallinity are the most significant factors; crystallinity in turn depends on molecular weight and degree of branching. The less the polymer chains are branched, and the lower the molecular weight, the higher the crystallinity of polyethylene. Crystallinity ranges from 35% (PE-LD/PE-LLD) to 80% (PE-HD). Polyethylene has a density of 1.0 g/cm 3 in crystalline regions and 0.86 g/cm 3 in amorphous regions. An almost linear relationship exists between density and crystallinity.
How is polyethylene classified?
Polyethylene is classified by its density and branching. Its mechanical properties depend significantly on variables such as the extent and type of branching, the crystal structure, and the molecular weight. There are several types of polyethylene:
What is polyethylene with multimodal weight distribution?
Polyethylene with multimodal molecular weight distribution consist s of several polymer fractions, which are homogeneously mixed. Such polyethylene types offer extremely high stiffness, toughness, strength, stress crack resistance and an increased crack propagation resistance. They consist of equal proportions higher and lower molecular polymer fractions. The lower molecular weight units crystallize easier and relax faster. The higher molecular weight fractions form linking molecules between crystallites, thereby increasing toughness and stress crack resistance. Polyethylene with multimodal molecular weight distribution can be prepared either in two-stage reactors, by catalysts with two active centers on a carrier or by blending in extruders.
What is the most common plastic in the world?
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly (methylene)) is the most common plastic in use today. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including bottles, etc.). As of 2017.
What is the melting point of polyethylene?
For common commercial grades of medium- and high-density polyethylene the melting point is typically in the range 120 to 130 °C (248 to 266 °F). The melting point for average commercial low-density polyethylene is typically 105 to 115 °C (221 to 239 °F).
Where does the name polyethylene come from?
The name polyethylene comes from the ingredient and not the resulting chemical compound, which contains no double bonds. The scientific name polyethene is systematically derived from the scientific name of the monomer. The alkene monomer converts to a long, sometimes very long, alkane in the polymerization process.
When was polyethylene first used?
The first industrially practical polyethylene synthesis (diazomethane is a notoriously unstable substance that is generally avoided in industrial application) was again accidentally discovered in 1933 by Eric Fawcett and Reginald Gibson at the Imperial Chemical Industries (ICI) works in Northwich, England.
What is poly alcohol used for?
Poly (vinyl alcohol) is used in the coating sector (e.g., as a thickening agent for aqueous systems), in adhesives, for finishing paper and cardboard, for coating paper, as a binder for strippable coatings, and as a protective colloid for dispersions. Funke W et al; Paints and Coatings, 2. Types.
What is polyvinyl alcohol?
Polyvinyl alcohol is a synthetic resin prepared by the polymerisation of vinyl acetate, followed by partial hydrolysis of the ester in the presence of an alkaline catalyst. The physical characteristics of the product depend on the degree of polymerisation and the degree of hydrolysis. EU Food Improvement Agents.
What is plastic compound?
In plastic industry in molding compounds, surface coatings, films resistant to gasoline, textile sizes and finishing compositions ; can be compounded to yield elastomers to be used in manufacturing artificial sponges, fuel hoses, etc., also in printing inks for plastics and glass, in pharmaceutical finishing, cosmetics, water -soluble film and sheeting. Pharmaceutic aid (viscosity increasing agent); ophthalmic lubricant.
What is the process of dissolving polyvinyl acetate?
Various indirect methods that involve alcoholysis (also called saponification or hydrolysis) of polyvinyl acetate are used to prepare polyvinyl alcohol. Preparation can be carried out by dissolving polyvinyl acetate in methanol or ethanol with alkaline or acid or acid catalyst and heating to precipitate the polyvinyl alcohol from the solution.
How long does polyvinyl alcohol stay on your back?
/HUMAN EXPOSURE STUDIES/ Twelve panelists were instructed to place patches containing 13% Polyvinyl Alcohol (in formulation) onto their backs for 23 hours of exposure for 21 consecutive days. Applications were made to the same site and were evaluated daily. The total irritation score of Polyvinyl Alcohol for all subjects for all 21 applications was 10 (maximum 756). The formulation containing Polyvinyl Alcohol was classified as a "mild material"
Is polyvinyl alcohol soluble in water?
AEROBIC: Polyvinyl alcohol is recognized as one of the very few vinyl polymers soluble in water and also susceptible of ultimate biodegradation in the presence of suitably acclimated microorganisms (1). Polyvinyl alcohol is one of few vinyl polymers that can have a higher biodegradation rate owing to the presence of hydroxyl groups which condition hydrophilic nature of this material (2). A Zahn-Wellens test using polyvinyl alcohol at 500 mg/L and a non-adapted activated sludge inoculum found 20, 50 and 90% degradation after 17, 24 and 28 days respectively (3); using an adapted activated sludge, 20, 50 and 90% degradation occurred after 0.5, 2 and 6 days respectively (3). The biochemical mineralization of polyvinyl alcohol in an activated sludge reactor reached 50-70% (4); the natural degradation of polyvinyl alcohol in water or soil occurs readily at 100% degradation in 30 days or less (4).
What is polyethylene glycol 3350 used for?
Polyethylene glycol 3350 is used as a laxative to treat occasional constipation or irregular bowel movements. Polyethylene glycol 3350 may also be used for purposes not listed in this medication guide.
How long does it take for polyethylene glycol 3350 to work?
Polyethylene glycol 3350 should produce a bowel movement within 1 to 3 days of using the medication. Polyethylene glycol 3350 normally causes loose or even watery stools. Do not use polyethylene glycol 3350 more than once per day. Call your doctor if you are still constipated or irregular after using this medication for 7 days in a row.
Can you take polyethylene glycol 3350 if you are allergic to it?
You should not use this medicine if you are allergic to polyethylene glycol , or if you have a bowel obstruction or intestinal blockage. If you have any of these conditions, you could have dangerous or life-threatening side effects from polyethylene glycol 3350.
Can polyethylene glycol cause diarrhea?
Stop taking polyethylene glycol 3350 and call your doctor at once if you have: severe or bloody diarrhea; rectal bleeding; blood in your stools; or. severe and worsening stomach pain. Common side effects may include: bloating, gas, upset stomach; dizziness; or. increased sweating.
Can polyethylene glycol be used in breast milk?
It is not known whether polyethylene glycol 3350 passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.
Can polyethylene glycol 3350 harm a baby?
if you have had a sudden change in bowel habits that has lasted 2 weeks or longer. FDA pregnancy category C. It is not known whether polyethylene glycol 3350 will harm an unborn baby .
What is polyethylene glycol found in?
Roberts. Polyethylene glycol is also found in several things you use every day: toothpaste, skin creams, and laxatives.
Why is P-E-G used in moderna?
Roberts says it's used for "stabilizing", and the reason it's used in the Pfizer and Moderna vaccines is that the little piece of genetics that's creating the response we want is very unstable. So the concern lies around whether polyethylene glycol, known as "P-E-G," is causing allergic responses. The reason is that it's ...
Does Moderna contain polyethylene glycol?
Both the Pfizer and Moderna vaccines contain polyethylene glycol. FILE - In this Feb. 25, 2021, file photo, vials for the Moderna and Pfizer COVID-19 vaccines are displayed on a tray at a clinic set up by the New Hampshire National Guard in the parking lot of Exeter, N.H., High School.
What is polyethylene glycol used for?
For example, it is used as an excipient in many pharmaceutical products.
What is the difference between polyethylene glycol and ethylene glycol?
The main difference between ethylene glycol and polyethylene glycol is that ethylene glycol has a fixed value for molecular weight whereas polyethylene glycol has no fixed value for molecular weight.
How is ethylene glycol produced?
Production. Ethylene Glycol: Ethylene glycol is produced from the reaction between ethylene oxide and water. Polyethylene Glycol: Polyethylene glycol is produced from the reaction between ethylene oxide and water , ethylene glycol or ethylene glycol oligomers.
What is the purpose of ethylene glycol?
The most common applications of ethylene glycol include its use as a raw material for the production of polyester fibers and as an automotive antifreeze.
What is the formula for polyethylene glycol?
Polyethylene glycol is a polyether compound. The general formula of this compound is given as H− (O−CH 2 −CH 2) n −OH. The molecular weight of the compound varies depending on the value of “n” in this general formula.
Is ethylene glycol a liquid?
At room temperature and pressure, ethylene glycol is a syrupy liquid. It is a viscous liquid. The boiling point of this liquid is about 198 °C.
Is polyethylene glycol a polyether?
Ethylene glycol is an alcoholic compound. Polyethylene glycol is a polyether compound. Both these compounds are miscible with water due to the presence of –OH groups.
Overview
Poly(vinyl alcohol) (PVOH, PVA, or PVAl) is a water-soluble synthetic polymer. It has the idealized formula [CH2CH(OH)]n. It is used in papermaking, textile warp sizing, as a thickener and emulsion stabilizer in PVAc adhesive formulations, in a variety of coatings, and 3D printing. It is colourless (white) and odorless. It is commonly supplied as beads or as solutions in water. Without an externally ad…
Uses
PVA is used in a variety of medical applications because of its biocompatibility, low tendency for protein adhesion, and low toxicity. Specific uses include cartilage replacements, contact lenses, and eye drops. Polyvinyl alcohol is used as an aid in suspension polymerizations. Its largest application in China is its use as a protective colloid to make polyvinyl acetate dispersions. In Japan its major use is the production of Vinylon fiber. This fiber is also manufactured in North Kor…
Preparation
Unlike most vinyl polymers, PVA is not prepared by polymerization of the corresponding monomer, since the monomer, vinyl alcohol, is thermodynamically unstable with respect to its tautomerization to acetaldehyde. Instead, PVA is prepared by hydrolysis of polyvinyl acetate, or sometimes other vinyl ester-derived polymers with formate or chloroacetate groups instead of acetate. The conversion of the polyvinyl esters is usually conducted by base-catalysed transeste…
Structure and properties
PVA is an atactic material that exhibits crystallinity. In terms of microstructure, it is composed mainly of 1,3-diol linkages [−CH2−CH(OH)−CH2−CH(OH)−], but a few percent of 1,2-diols [−CH2−CH(OH)−CH(OH)−CH2−] occur, depending on the conditions for the polymerization of the vinyl ester precursor.
Polyvinyl alcohol has excellent film-forming, emulsifying and adhesive properties. It is also resista…
Safety and environmental considerations
PVA is widely used, thus its toxicity and biodegradation are of interest. Solutions containing more than 5% PVA are toxic to fish. It biodegrades slowly.
See also
• Polyvinyl acetate
• Vinyl acetate
• Polymerization
• Polyvinyl nitrate
External links
• MSDS
• "Slime" recipe
• Forming PVA layers in PET bottles
Overview
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most common plastic in use today. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bottles, etc.). As of 2017 , over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the tot…
Chemically modified polyethylene
Polyethylene may either be modified in the polymerization by polar or non-polar comonomers or after polymerization through polymer-analogous reactions. Common polymer-analogous reactions are in case of polyethylene crosslinking, chlorination and sulfochlorination.
In the low pressure process α-olefins (e.g. 1-butene or 1-hexene) may be added, which are incorporated in the polymer chain during polymerization. These copolymers introduce short sid…
History
Polyethylene was first synthesized by the German chemist Hans von Pechmann, who prepared it by accident in 1898 while investigating diazomethane. When his colleagues Eugen Bamberger and Friedrich Tschirner characterized the white, waxy substance that he had created, they recognized that it contained long −CH2− chains and termed it polymethylene.
Properties
The properties of polyethylene can be divided into mechanical, chemical, electrical, optical, and thermal properties.
Polyethylene is of low strength, hardness and rigidity, but has a high ductility and impact strength as well as low friction. It shows strong creep under persistent force, which can be reduced by addition of short fibers. It feels waxy when touched.
Manufacturing process
The ingredient or monomer is ethylene (IUPAC name ethene), a gaseous hydrocarbon with the formula C2H4, which can be viewed as a pair of methylene groups (−CH 2−) connected to each other. Typical specifications for PE purity are <5 ppm for water, oxygen, and other alkenes contents. Acceptable contaminants include N2, ethane (common precursor to ethylene), and metha…
Joining
Commonly used methods for joining polyethylene parts together include:
• Welding
• Fastening
• Adhesives
Adhesives and solvents are rarely used because polyethylene is nonpolar and has a high resistanc…
Classification
Polyethylene is classified by its density and branching. Its mechanical properties depend significantly on variables such as the extent and type of branching, the crystal structure, and the molecular weight. There are several types of polyethylene:
• Ultra-high-molecular-weight polyethylene (UHMWPE)
Environmental issues
Polyethylene is produced from ethylene, and although ethylene can be produced from renewable resources, it is mainly obtained from petroleum or natural gas.
Moreover, the widespread usage of polyethylene poses difficulties for waste management if it is not recycled. Polyethylene, like other synthetic plastics, is not readily biodegradable, and thus accumulates in landfills. Recycling is mad…