Poly(vinyl alcohol)

Gefahreninformationscode (GHS)

• Bildanzeige (GHS)

  

• Alarmwort

  Warnung

• Gefahrenhinweise

  H371：Kann die Organe schädigen.

• Sicherheit

  P260：Dampf/Aerosol/Nebel nicht einatmen.

Poly(vinyl alcohol) Chemische Eigenschaften,Einsatz,Produktion Methoden

• ERSCHEINUNGSBILD

  FARBLOSER BIS WEISSER FESTSTOFF IN VERSCHIEDENEN FORMEN.

• PHYSIKALISCHE GEFAHREN

  Staubexplosion der pulverisierten oder granulierten Substanz in Gemischen mit Luft möglich. Fließen, Schütten o.ä. kann zu elektrostatischer Aufladung führen.

• CHEMISCHE GEFAHREN

  Zersetzung beim Erhitzen und beim Verbrennen unter Bildung giftiger Rauche. Reagiert mit Oxidationsmitteln und starken Säuren.

• ARBEITSPLATZGRENZWERTE

  TLV nicht festgelegt (ACGIH 2005).
  MAK nicht festgelegt (DFG 2005).
  

• INHALATIONSGEFAHREN

  Nur ungenügende Angaben vorhanden über die Geschwindigkeit, mit der eine gesundheitsschädliche Konzentration in der Luft beim Verdampfen bei 20°C erreicht wird.

• WIRKUNGEN BEI KURZZEITEXPOSITION

  WIRKUNGEN BEI KURZZEITEXPOSITION:
  Reizt möglicherweise mechanisch.

• LECKAGE

  Persönliche Schutzausrüstung: Atemschutzgerät, P1-Filter für inerte Partikel. Verschüttetes Material in geeigneten Behältern sammeln. NICHT in die Umwelt gelangen lassen.

• R-Sätze Betriebsanweisung:

  R23/24/25:Giftig beim Einatmen, Verschlucken und Berührung mit der Haut.
  R36/38:Reizt die Augen und die Haut.
  R39/23/24/25:Giftig: ernste Gefahr irreversiblen Schadens durch Einatmen, Berührung mit der Haut und durch Verschlucken.

• S-Sätze Betriebsanweisung:

  S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
  S36/37:Bei der Arbeit geeignete Schutzhandschuhe und Schutzkleidung tragen.
  S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
  S24/25:Berührung mit den Augen und der Haut vermeiden.

• Chemische Eigenschaften

  Polyvinyl alcohol occurs as an odorless, white to cream-colored granular powder.

• Verwenden

  NaA zeolite particles have been dispersed in a poly(vinyl alcohol) matrix to prepare a mixed-matrix membrane to study the pervaporative separation of water-butanol mixtures. Poly (vinyl alcohol)/gelatin based biocompatible polymeric scaffolds have been used to design for 3D cancer models.

• Verwenden

  Mowiol^? 40-88 can be used for a variety of applications such as drug delivery, surface enhanced Raman spectroscopy (SERS) fiber-optic sensors, and transparent conducting oxides (TCOs).

• Verwenden

  In the plastics 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 manufacture of artificial sponges, fuel hoses, etc., also in printing inks for plastics and glass, in pharmaceutical finishing, cosmetics, water-sol film and sheeting. Pharmaceutic aid (viscosity increasing agent); ophthalmic lubricant.

• Vorbereitung Methode

  Polyvinyl alcohol is produced through the hydrolysis of polyvinyl acetate. The repeating unit of vinyl alcohol is not used as the starting material because it cannot be obtained in the quantities and purity required for polymerization purposes. The hydrolysis proceeds rapidly in methanol, ethanol, or a mixture of alcohol and methyl acetate, using alkalis or mineral acids as catalysts.

• Definition

  ChEBI: Polyvinyl alcohol is a homopolymer macromolecule obtained by polymerisation of vinyl alcohol. It is used as a pharmaceutic aid and ophthalmic lubricant as well as in the manufacture of surface coatings artificial sponges, cosmetics, and other products.

• synthetische

  Vinyl alcohol has not been isolated in the free state; the keto tautomer, acetaldehyde, is much the more stable form and is always obtained:
  

  

  
  Thus poly(vinyl alcohol) cannot be prepared from its monomer by the usual techniques, although the polymerization of acetaldehyde with sodium amalgam at - 80 to - 20?? has been found to give poly( vinyl alcohol) of low molecular weight. For commercial purposes, poly(vinyl alcohol) is obtained exclusively from poly(vinyl acetate).
  Poly(vinyl acetate) is readily hydrolysed by treating an alcoholic solution with aqueous acid or alkali. Acid hydrolysis results in traces of acid in the poly(vinyl alcohol) which are difficult to remove and which lead to instability of the polymer; alkaline hydrolysis results in contamination of the product by a large amount of sodium acetate which is also difficult to remove and which has little intrinsic value. These difficulties are avoided if poly(vinyl alcohol) is prepared from poly(vinyl acetate) by alcoholysis using a small amount of base as catalyst. The reaction is commonly carried out by treating poly(vinyl acetate) with methanol in the presence of sodium methoxide:
  

  

  
  The preferred methods of preparing poly(vinyl acetate) for conversion to poly(vinyl alcohol) are solution and suspension polymerization. The former technique has the advantage that if polymerization is conducted in methanol the resulting solution can be used directly without the need for isolating the polymer; this method is the most suitable for continuous processes. Bulk polymerized poly(vinyl acetate) tends to give low molecular weight poly(vinyl alcohol) of poor colour.
  In one continuous process, a solution of poly(vinyl acetate) in methanol (about 20%) is mixed with the catalyst solution in a high speed in-line mixer. The mixture then passes through a 'gelling zone' on a conveyor belt. Typically, the material is kept at 40?? for 10 minutes in this zone during which time the alcoholysis reaction occurs; poly(vinyl alcohol) is insoluble in methanol and a gel is produced. The gel is chopped up and neutralized with acetic acid to stop reaction; the liquid content (whica is mainly methanol and methyl acetate) is then expressed and recovered. The residual solid is washed with methanol, dried and pulverized.
  It is possible to control the extent to which acetate groups are replaced by hydroxyl groups by changing the reaction conditions. In particular, the catalyst concentration and the time of reaction have a major effect on the degree of alcoholysis. The most common commercial types of poly(vinyl alcohol) are the so-called partially hydrolysed grades in which 87-89% of the acetate groups have been replaced and the completely hydrolysed grades in which 99-100% of the acetate groups have been replaced. The degree of alcoholysis has an effect on the properties of the polymer.

• Trademarks

  Liquifilm Tears (Allergan).

• Allgemeine Beschreibung

  Polyvinyl alcohol (PVOH) is a hydrophilic linear polymer which forms copolymers of vinyl alcohol and vinyl acetate. Hence, the structural properties of polyvinyl alcohol polymers depend on the extent of polymerization and hydrolysis. Such changes cause both chemical and physical modifications such as esterification, etherification, crystallization, ion-polymer complexation in the polymer. Modified- PVOH structures are useful in biomedical applications.

• Pharmazeutische Anwendungen

  Polyvinyl alcohol is used primarily in topical pharmaceutical and ophthalmic formulations. It is used as a stabilizing agent for emulsions (0.25–3.0% w/v). Polyvinyl alcohol is also used as a viscosity-increasing agent for viscous formulations such as ophthalmic products. It is used in artificial tears and contact lens solutions for lubrication purposes, in sustained-release formulations for oral administration, and in transdermal patches. Polyvinyl alcohol may be made into microspheres when mixed with a glutaraldehyde solution.

• Industrielle Verwendung

  Polyvinyl alcohol is a tough, whitish polymerthat can be formed into strong films, tubes, andfibers that are highly resistant to hydrocarbonsolvents. Although polyvinyl alcohol is one ofthe few water-soluble polymers, it can be renderedinsoluble in water by drawing or by theuse of cross-linking agents.

• Biochem/physiol Actions

  Poly(vinyl alcohol) (PVA) is a polyhydroxy polymer, soluble in water. PVA is known to possess high mechanical strength, biocompatibility and non-toxicity. Hence, it serves as a biomedical implant material. Polymerization of vinyl acetate to poly (vinyl acetate), which is then hydrolysed to form PVA. Its application is observed in drug delivery systems, wound dressing, dialysis membranes, artificial skin, surgical repairs and cardiovascular devices.

• Sicherheitsprofil

  Questionable carcinogen with experimental carcinogenic and tumorigenic data by implant route. Flammable when exposed to heat or flame; can react with oxidizing materials. Slight explosion hazard in the form of dust when exposed to flame. To fight fire, use alcohol foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes.

• Sicherheit(Safety)

  Polyvinyl alcohol is generally considered a nontoxic material. It is nonirritant to the skin and eyes at concentrations up to 10%; concentrations up to 7% are used in cosmetics.
  Studies in rats have shown that polyvinyl alcohol 5% w/v aqueous solution injected subcutaneously can cause anemia and infiltrate various organs and tissues.
  (mouse, oral): 14.7 g/kg
  (rat, oral): >20 g/kg

• Solubility in organics

  Glycerol (hot), glycols (hot), water

• Lager

  Polyvinyl alcohol is stable when stored in a tightly sealed container in a cool, dry place. Aqueous solutions are stable in corrosionresistant sealed containers. Preservatives may be added to the solution if extended storage is required. Polyvinyl alcohol undergoes slow degradation at 100°C and rapid degradation at 200°C; it is stable on exposure to light.

• Inkompatibilitäten

  Polyvinyl alcohol undergoes reactions typical of a compound with secondary hydroxy groups, such as esterification. It decomposes in strong acids, and softens or dissolves in weak acids and alkalis. It is incompatible at high concentration with inorganic salts, especially sulfates and phosphates; precipitation of polyvinyl alcohol 5% w/v can be caused by phosphates. Gelling of polyvinyl alcohol solution may occur if borax is present.

• Regulatory Status

  Included in the FDA Inactive Ingredients Database (ophthalmic preparations and oral tablets). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.

Poly(vinyl alcohol) Upstream-Materialien And Downstream Produkte

Poly(vinyl alcohol) Anbieter Lieferant Produzent Hersteller Vertrieb Händler.

Global(771)Suppliers

9002-89-5, Poly(vinyl alcohol) Verwandte Suche: