Polyvinyl alcohol (PVA) Molecular composition and structure :(CH3CHCOOCH3) x (CH2CHOH) y Where, x + y represents the degree of polymerization, and y/ (x + y) represents the degree of alcoholysis Physical properties: Appearance is white flake, granular or powdery solid (low alkali alcoholysis process) or white flocculent solid (high alkali alcoholysis process). Specific gravity: 1.23-1.31g/cm3, flake PVA filling specific gravity: 0.42-0.52g/cm3, flocculated PVA filling specific gravity: 0.20-0.27g/cm3. Chemical properties: The structural formula of PVA is -[CH2CH(OH)] N -, where N represents the average degree of polymerization. The basic properties of PVA are determined by its average degree of polymerization and alcoholysis, but there are more than 10 irregular structures in PVA molecules, which greatly affect its properties. (1) Water solubility: PVA molecule is soluble in water because it contains a large number of hydroxyl groups. Its solubility increases with the increase of water temperature, only expansion in cold water (low alcoholysis products can slowly dissolve in normal water), in hot water can be completely dissolved, its aqueous solution has good film formation and cohesiveness. (2) Thermal stability: this series of products soften when heated, there is no significant change below 40ºC, over 160ºC for a long time heating will gradually color, above 220ºC decomposition, water, acetic acid, acetaldehyde and butenal. (3) Chemical resistance: this series of products are almost not affected by weak acid, weak alkali or organic solvent, high oil resistance. (4) Storage stability: this series of products have good stability, no mildew, no deterioration, no moisture absorption in the natural dry state storage for a long time. (5)PVA is a kind of polymer with secondary hydroxyl group. The secondary hydroxyl group in the molecular formula of PVA has high activity, and can carry out typical chemical reactions similar to low molecular alcohol, such as esterification, etherification, acetal, etc., and also react with many inorganic and organic compounds. Harmless to people and animals, can be naturally degradable, known as green products. Storage and transportation conditions and market application (1) Polyvinyl alcohol (PVA) is made from vinyl acetate by polymerization reaction, alcoholysis, is a kind of white, stable, harmless water-soluble polymer, can quickly dissolve in water, forming a stable colloid, water is a good solvent. (2) Polyvinyl alcohol resin (PVA) aqueous solution has good film formation and emulsification. The formed film has different adhesion force, solvent resistance, friction resistance, tensile strength and oxygen resistance. Polyvinyl alcohol resin (PVA) has both hydrophilic and hydrophobic functional groups, so it is a material with interfacial activity, so it can be used as a protective colloid in polymer emulsification and suspension polymerization reaction. (3) Polyvinyl alcohol resin (PVA) is mainly used in the production of synthetic fiber, plastics, adhesives, coatings, new building materials and other products, and is widely used in chemical industry, textile, printing and paper making, leather industry, construction and other industries and fields. Polyvinyl alcohol
Polyvinyl alcohol is an organic compound with the chemical formula [C2H4O]n. It appears as a white flaky, fibrous, or powdery solid, odorless. It is soluble in water (above 95°C), slightly soluble in dimethyl sulfoxide, and insoluble in gasoline, kerosene, vegetable oil, benzene, toluene, dichloroethane, carbon tetrachloride, acetone, ethyl acetate, methanol, ethylene glycol, etc. Polyvinyl alcohol is an important industrial raw material used in the production of polyvinyl acetal, gasoline-resistant pipes, vinylon, fabric treatment agents, emulsifiers, paper coatings, adhesives, glue, etc.
On October 27, 2017, the International Agency for Research on Cancer (IARC) of the World Health Organization preliminarily listed polyvinyl alcohol in the Group 3 carcinogen list.
On May 30, 2019, a new international study found that polyvinyl alcohol, commonly found in glue, can be used in the culture medium for hematopoietic stem cells. This discovery is expected to significantly reduce the cost of hematopoietic stem cell cultivation and aid in the treatment of diseases such as leukemia.
### Physicochemical Properties The physical properties of polyvinyl alcohol are influenced by its chemical structure, degree of alcoholysis, and polymerization. The main structure in polyvinyl alcohol molecules is 1,3-propanediol, i.e., a "head-to-tail" arrangement.
Polyvinyl alcohol is classified by polymerization degree into: - Ultra-high polymerization (molecular weight 250,000-300,000) - High polymerization (molecular weight 170,000-220,000) - Medium polymerization (molecular weight 120,000-150,000) - Low polymerization (molecular weight 25,000-35,000)
The degree of alcoholysis typically falls into three categories: 78%, 88%, and 98%. Partial alcoholysis usually ranges from 87% to 89%, while complete alcoholysis ranges from 98% to 100%. The naming convention combines the average polymerization degree (thousands and hundreds digits) with the alcoholysis percentage, e.g., 17-88 indicates a polymerization degree of 1700 and alcoholysis degree of 88%.
Generally, as polymerization degree increases, the viscosity of aqueous solutions rises, and the strength and solvent resistance of films improve, but water solubility and film elongation decrease.
- **Relative Density (25°C/4°C):** 1.27-1.31 (solid), 1.02 (10% solution) - **Melting Point:** 230 °C - **Glass Transition Temperature:** 75-85 °C - **Thermal Stability:** Begins to discolor and embrittle above 100°C in air. Dehydrates and etherifies at 160-170°C, losing solubility. Decomposes at 200°C. Above 250°C, it transforms into a polymer with conjugated double bonds. - **Refractive Index:** 1.49-1.52 - **Thermal Conductivity:** 0.2 W/(m·K) - **Specific Heat Capacity:** 1-5 J/(kg·K) - **Resistivity:** (3.1-3.8) × 10 Ω·cm
### Solubility - Soluble in water (requires heating to 65-75°C for complete dissolution). - Insoluble in gasoline, kerosene, vegetable oil, benzene, toluene, dichloroethane, carbon tetrachloride, acetone, ethyl acetate, methanol, ethylene glycol, etc. - Slightly soluble in dimethyl sulfoxide. - Dissolves in glycerol at 120-150°C but forms a gel upon cooling to room temperature.
### Dissolution Method For dissolution, the material should first be dispersed in room-temperature water under stirring before heating to accelerate dissolution, preventing clumping and ensuring uniform dissolution.
### Solution Behavior - A 5% aqueous solution is highly sensitive to borax and boric acid, leading to gelation. Gelation becomes irreversible when borax reaches 1% of the solution mass. - Chromates, dichromates, and permanganates can also induce gelation. - PVA 17-88 aqueous solutions show increasing viscosity over time at room temperature, but an 8% concentration maintains stable viscosity indefinitely.
### Film Properties - Excellent film-forming ability. - High impermeability to most gases except water vapor and ammonia. - Light-resistant, unaffected by exposure to light. - Combustible upon contact with open flame, emitting a distinct odor. - Aqueous solutions may develop mold during storage. - Non-toxic and non-irritating to human skin.
### Applications - Emulsifying stabilizer in polyvinyl acetate emulsion polymerization. - Used in water-soluble adhesives. - Modifier for starch-based adhesives. - Preparation of photosensitive resins and solvent-resistant sealants. - Used as a release agent, dispersant, etc.
### Storage Store in a cool, dry warehouse. Protect from moisture and fire.
### Variants 1. **PVA 17-92** - White granules or powder. - Soluble in water at 75-80°C. - Properties similar to PVA 17-88. - Used as an emulsifying stabilizer in emulsion polymerization and in water-soluble adhesives. - Store in a cool, dry warehouse; protect from fire and moisture.
2. **PVA 17-99 (Sizing Resin)** - White or light-yellow powder/fibrous solid. - Glass transition temperature: 85°C. - Saponification value: 3-12 mg KOH/g. - Soluble in hot water (90-95°C), nearly insoluble in cold water. - Solutions above 10% concentration gel at room temperature but regain fluidity upon heating. - Viscosity stabilizers (e.g., sodium thiocyanate, calcium thiocyanate, phenol, butanol) can be added. - More sensitive to borax-induced gelation than PVA 17-88 (0.1% borax gels a 5% solution). - Borax causes gelation more readily than boric acid at the same concentration and alcoholysis degree. - Better resistance to aromatic, chlorinated, ester, ketone, ether, and hydrocarbon solvents compared to PVA 17-88. - Discolors above 100°C, rapidly at 150°C, and decomposes above 200°C. - Discoloration can be suppressed by adding 0.5-3% boric acid. - Light-resistant, chemically reactive (esterification, etherification, acetalization). - Combustible with a distinct odor; non-toxic and non-irritating.
### Special Applications - **PVA 17-99B:** Primarily used in high-viscosity polyvinyl butyral production and as a dispersant in sizing agents. - Other PVA 17-99 types are used as emulsifying stabilizers in polyvinyl acetate emulsion polymerization (often mixed with PVA 17-88 for better results). - Used in polyvinyl formal aqueous solutions (e.g., 107 construction adhesive). - Also used in solvent-resistant sealants.
Applications Used in the manufacture of polyvinyl acetal, gasoline-resistant pipes, vinylon, fabric treatment agents, emulsifiers, paper coatings, adhesives, etc.
Technical Specifications Polyvinyl Alcohol Product Standard (CP2010)
| No. | Indicator Name | Standard | |-----|-|-| | 1 | Appearance | White solid powder | | 2 | Viscosity | 3-70 | | 3 | pH Value | 4.5-6.5 | | 4 | Loss on Drying | ≤5.0 | | 5 | Residue on Ignition | ≤0.5 | | 6 | Acid Value | ≤3.0% | | 7 | Degree of Alcoholysis | 85-89 | | 8 | Heavy Metals | ≤10 ppm |
The grades and specifications of pharmaceutical-grade ethylene glycol (EG) and its applications in EG systems. Pharmaceutical-grade polyvinyl alcohol differs from industrial-grade polyvinyl alcohol. It is an extremely safe high-molecular organic compound, non-toxic to humans, with no side effects, and exhibits excellent biocompatibility. It is widely used in medical applications, such as aqueous gels in ophthalmology, wound dressings, and artificial joints. Additionally, polyvinyl alcohol films are utilized in pharmaceutical membranes and artificial kidney membranes, among others. Its safety is evident in applications like wound skin repair and eye drop products. Some grades are also commonly used in cosmetics, such as facial masks, cleansing creams, toners, and emulsions, serving as a safe film-forming agent.
**First Aid Measures**
| Exposure Site | First Aid Measures | |-|-| | Skin Contact | Remove contaminated clothing and rinse with running water. | | Eye Contact | Lift eyelids and rinse with running water or saline. Seek medical attention. | | Inhalation | Move to fresh air. Administer oxygen if breathing is difficult. Seek medical help. | | Ingestion | Drink plenty of warm water and induce vomiting. Seek medical attention. |
**Spill Handling** Isolate the contaminated area and restrict access. Eliminate ignition sources. Emergency personnel should wear full-face dust masks and chemical protective clothing. Avoid raising dust; sweep up carefully and transfer to sealed bags for safe disposal. Alternatively, rinse with large amounts of water, dilute the wash water, and discharge into the wastewater system. For large spills, cover with plastic sheets or tarps. Collect and recycle or dispose of at a designated waste facility.
**Protective Measures**
| Protection Area | Protective Measures | |-|-| | Respiratory | Wear a self-contained dust respirator if dust concentration exceeds limits. Use an air-supplied respirator in emergencies. | | Eyes | Wear chemical safety goggles. | | Body | Wear chemical-resistant clothing. | | Hands | Wear rubber gloves. | | Other | No smoking in the work area. Maintain good hygiene practices. |
**Handling and Storage**
**Handling Precautions:** Ensure adequate natural ventilation. Operators must be specially trained and strictly follow procedures. It is recommended to wear a self-contained dust respirator, chemical safety goggles, chemical-resistant clothing, and rubber gloves. Keep away from ignition sources and heat; smoking is prohibited in the workplace. Use explosion-proof ventilation systems and equipment. Avoid generating dust and contact with oxidizers. Handle with care to prevent packaging damage. Equip with appropriate firefighting and spill response tools. Empty containers may retain hazardous residues.
**Storage Precautions:** Store in a cool, well-ventilated area away from ignition sources and heat. Separate from oxidizers. Provide suitable firefighting equipment and spill containment materials in storage areas.
Company Introduction Suzhou Trillion Shine Import & Export Co.,Ltd (Trillion Shine) is a leading Chinesesupplier of Polyvinyl alcohol(PVA) and also provides services for sourcing all related products from China since 2003.
Relying on Chinese complete industry Chain and enjoying price advantages, we provide customers with premium products, reasonable prices,and on-time services. Trillion Shine has a professional technique team who has been in this industry for more than 22 years, consists of advanced mechanics, engineers and professors. Powerful technical capabilities extend our core competence to analysis of customer's demand and provide customer with satisfying service.
Trillion Shine has already established business relations with customersfrom South America, North America, Europe, Middle East, Southeast Asia and South Asia, obtained the customer affirmation and faith. The good faith manner,the premium quality product, the exquisite service and the customer first principle are Trillion Shine's service objective. Trillion Shine sincerely wish to establish stable business relationship with customers all over the world, please feel free to contact with us.
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