Typical Properties
SELVOL™ polyvinyl alcohols have many characteristics which make them useful in a wide range of applications. By choosing from the many SELVOL™ polyvinyl alcohol grades available, it is possible to obtain the performance properties required for your specific applications-properties such as water solubility, abrasion resistance, tensile strength, adhesive and bonding properties, grease or oil resistance and film forming qualities. Our highly skilled technical service group can help you with SELVOL™ polyvinyl alcohol grade selection.
Changes Occurring in the Properties of Polyvinyl Alcohol as the Degree of Hydrolysis and Molecular Weight Change
Viscosity / Concentration Relationships of Aqueous SELVOL™ Solutions at 20 %
SELVOL™ Polyvinyl Alcohol Molecular Weight
| Viscosity | Viscosity Type | Degree of Polymerization | Weight Average Molecular Weight Range |
|---|---|---|---|
| 3-4 cps | Ultra Low | 150-300 | 13,000-23,000 |
| 5-6 cps | Low | 350-650 | 31,000-50,000 |
| 22-30 cps | Medium | 1000-1500 | 85,000-124,000 |
| 45-72 cps | High | 1600-2200 | 146,000-186,000 |
Physical Properties
SELVOL™ polyvinyl alcohol combines high tensile strength with ease of film formation. Additionally, SELVOL™ resins show excellent adhesive and bonding characteristics.Partially hydrolyzed grades have better adhesion to hydrophobic surfaces.
The degree of hydrolysis affects the water sensitivity of both the resin and film. Water resistance increases with increasing hydrolysis. The super hydrolyzed grades should be used when maximum water resistance and humidity resistance are desired.
SELVOL™ polyvinyl alcohol resins are generally unaffected by greases, petroleum hydrocarbons and animal or vegetable oils. Resistance to organic solvents increases with the degree of hydrolysis. SELVOL™ polyvinyl alcohol film can be plasticized with glycerol or the lower molecular weight glycols. These materials generally act as humectants, holding water in the film.
Physical Properties of Polyvinyl Alcohol
| Appearance | White-to-cream granular powder |
| Bulk Density | 40 lbs/cu ft |
| Specific Gravity — of solid — of 10 wt % solid at 25°C | 1.27 - 1.31 1.02 |
| Thermal Stability | Gradual discoloration about 100°C; darkens rapidly above 150°C; rapid decomposition above 200°C |
| Thermal Conductivity, W/(m•K)3 | 0.2 |
| Electrical Resistivity, ohm•cm | (3.1 - 3.8) x 107 |
| Specific Heat, J/(g•K)b | 1.5 |
| Melting Point (unplasticized), °C | 230 for fully hydrolyzed grades; 180-190 for partially hydrolyzed grades |
| Tg, °C (dry film) | 75-85 |
| Storage Stability (solid) | Indefinite when protected from moisture |
| Flammability | Burns similarly to paper |
| Stability to Sunlight | Excellent |
Notes
a. To convert W/(m•K) to (Btu•in)/(h•ft2•F), divide by 0.1441.
b. To convert J to cal, divide by 4.184.
Chemical Reactions
Polyvinyl alcohol resins react in a manner similar to other secondary polyhydric alcohols. Esterification reactions of polyvinyl alcohol can be carried out with a number of compounds. A commercially important reaction is the formation of tackified PVOH using boric acid or borax to form cyclicesters. This reaction is very sensitive to pH, and an insoluble gel is formed above 4.5-5.0.
Other esterification reactions include those with chloroformate esters to yield polyvinyl carbonate, with urea to yield a polymeric carbamate ester, and with isocyanates to form substituted carbamate esters.
Another commercially important reaction is acetalization with aldehydes. Polyvinyl butyral is produced by the reaction of polyvinyl alcohol with butyraldehyde and is used in the production of the inner adhesive film for safety glass. Reaction with dialdehydes such as glyoxal or gluteraldehyde can be used to crosslink polyvinyl alcohol. Other reactions include ethoxylation, propoxylation and cyanoethylation.
Packaging and Storage
SELVOL™ products are available in many packages:
Granular/Powder product 25 KG, 500 KG, 1000 KG
Solutions product 450 LB drums, 2250 LB tote
Other packaging may be available. For more information, please contact us.
