Project @ a Glance - Polyvinyl alcohol (PVOH, PVA, or PVAL) is a water-soluble synthetic polymer.
Polyvinyl alcohol has excellent film forming, emulsifying, and adhesive
properties. It is also resistant to oil, grease and solvent. It is odorless and
nontoxic. It has high tensile strength, flexibility, as well as high oxygen and
aroma barrier.
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Unlike most vinyl polymers, PVA is not prepared by polymerization of the
corresponding monomer. The monomer, vinyl alcohol, almost exclusively exists as
the tautomeric form, acetaldehyde. PVA instead is prepared by partial or
complete hydrolysis of polyvinyl acetate to remove acetate groups. Sizing is a
processing aid applied to rovings and yarns to provide lubricity and binding
action to protect the fibers and assist in handling. 299 and 399 organic sizing
composed of polyvinyl alcohol(PVA) and additives (plasticizers, lubricants,
etc.) is designed for easy removal by heat cleaning.
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The primary raw material used in the manufacture of polyvinyl alcohol is vinyl
acetate monomer. It is manufactured by the polymerization of vinyl acetate
followed by partial hydrolysis. The process of hydrolysis is based on the
partial replacement of ester group in vinyl acetate with the hydroxyl group, and
is completed in the presence of aqueous sodium hydroxide. Following gradual
addition of the aqueous saponification agent. Polyvinyl alcohol is precipitated,
washed and dried.
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There are two methods for preparing a 4% aqueous solution of polyvinyl
alcohol, the conventional heating method and the microwave heating method.
The microwave method is much easier and less time consuming. Once the 4%
polyvinyl alcohol solution is made it will last 6 to 8 weeks. It is a good
idea to store this solution in a refrigerator, as it will support bacteria
growth. It is recommended that tap water be used when making the polyvinyl
alcohol solution. Bacteria will grow much faster in a polyvinyl alcohol
solution that contains distilled water. Polyvinyl alcohol and its solutions
are considered non-toxic.
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Semicrystalline films of poly(vinyl alcohol) (PVA) were prepared by
annealing amorphous PVA films at temperatures above the glass transition temperature of 85°C, thus allowing the macromolecules to form crystallites,
which stabilized the films and made them behave as if they were chemically
cross-linked. Films were prepared by casting a 15% aqueous PVA solution onto
glass slides and annealing them at temperatures ranging from 90 to 120°C at
15 to 90 min.
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PVA is widely used in freshwater sport fishing. Small bags made from PVA are
filled with dry- or oil-based bait and attached to the hook, or the baited
hook is placed inside the bag and cast into the water. When the bag lands on
the lake or river bottom it breaks down, leaving the hook bait surrounded by
ground bait, pellets etc. This method helps attract fish to the hook bait,
though it does result in dissolved plastic in the water.
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Biodegradable polymer market in the US has witnessed a series of
consolidations over the past 10 years. In 2003 there were more than 7
players in the US Biodegradable polymer market. The U.S. biodegradable
polymer market revenues were estimated at $27.0 million, corresponding to
22.9 million pounds of unit shipment. The U.S. biodegradable polymer market
revenue is forecast to grow to $67.8 million in 2010 at a compound annual
growth rate (CAGR) of 12.2 percent.
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German chemicals group BASF has launched two new pharmaceutical film-coating
products, cementing its position in a market estimated to be worth about
€200 million and growing at 5 to 6 per cent a year. Last year, BASF launched
Kollicoat IR, the first of a new generation of excipients based on polyvinyl
alcohol-polyethylene glycol copolymer.
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The use of polyvinyl alcohol (PVA) as a coating agent for food supplements
poses no health risks, according to a recent EFSA investigation. The
European supplements market was estimated to be worth 5.2 billion in 2005,
with growth rate expected to peak at 4.4 percent over this year before
dropping to a steady 4.1 percent for the subsequent five years. By 2011, the
market is predicted to be worth around 6.6 billion.
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Chemicals company DuPont said Friday its packaging and industrial polymers
unit is raising its worldwide price for its Elvanol polyvinyl alcohol by 8
cents per pound. The company said high energy, transportation and raw
material costs resulted in the price increase, which are effective June 1,
or as contracts permit. Elvanol polyvinyl alcohol is used in a variety of
industries including textiles, paper, adhesives and films.
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There are over 22 producers worldwide with ~ 1 million tons on the open
market in 2002. Larger producers include Kuraray (Japan) and Celanese (USA)
but mainland China has installed a number of very large production
facilities in the past decade. In 1998, Western Europe has been the major
importer of PVA, so it can be considered as a target market. India and
Pakistan can also be considered as target markets. The domestic demand of
PVA is estimated to be at least 5,000 Tons per annum for the next coming
years.
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PVOH demand in Asia (except China) was almost flat in 2006 as compared with
2005 when the market plummeted by 10% or so. Moves of PVOH demand appear to
be very erratic, affected by inventories in the distribution channel. In
2007 so far, there is no sign of PVOH demand increasing significantly. Under
these circumstances, PVOH prices in Asia are not strong at the moment and
remain depressed around $2000/ton cfr for most representative commodity
grades. Prices for big accounts are slightly below $2000/tonb cfr.
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The combined exports of China and Taiwan amounted to about 38,700 tons in
2006, and if the exports are regulated by the anti-dumping problem, these
exports must find out other markets. Due to the growth potential, Asian
markets including the Chinese domestic market should be home for such
material. But, if Chinese producers aggressively increase the production
capacity, the problem may not be so
simple.
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General
Process
Reactions of Polyvinyl Alcohol with Clay
Thermal and Physical Properties
Company Profiles
Consultants
Patent
| Products Material Safety Data Sheet Aspects of Polyvinyl Alcohol |
