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PVA 2488 powder

China

-

2000 ~ 2400 / Metric Ton ( Negotiable ) Obtener el precio más reciente

china

2000 per Metric Ton

1 Metric Ton

plastic bag

7 days

1000 Metric Ton per Month

PayPal, Money Gram, Western Union, D/P, L/C, T/T

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Especificaciones del producto

Purity (%) : 99% Usage : Textile Auxiliary Agents Brand Name : Qingquan brand Classification : - CAS No. : - Other Names : - MF : - EINECS No. : - Type : -
white powder : $2400

Descripción del producto

Products Description
Polyvinyl alcohol is an excellent water-based adhesive property. Generally speaking, the product is in the form of flakes, granules or flocs. It is not easily dissolved in cold water, when it is dissolved, heating is generally required. This property greatly limits its application range. However, if subjecting it to fine pulverization and surface treatment, it will have a good cold water solubility. But due to its thermoplasticity, it is difficult to be in the pulverization process.
 
The vinyl acetate is generated by the polymerization of vinyl acetate and then the polyvinyl alcohol with different degree of alcoholysis can be gained through the polyvinyl acetate in different alkali amount. The cold-soluble polyvinyl alcohol powder a water-soluble environment-friendly white solid powder prepared by deep-cooling milling of a partially alcoho-decomposing polyvinyl alcohol.
 
It has good film forming properties and adhesion, solvent resistance, abrasion resistance and tensile strength.
 
The particles are fine, the amount of addition is small, and it is easy to disperse. It can be dissolved in cold water. Providing good bonding properties and increasing mortar strength. Prevention cracking and detachment of mortar, increasing the adhesion strength and smoothness.This product is non-toxic, tasteless and environmental friendly.
 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.[5] 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 Korea for self-sufficiency reasons, because no oil is required to produce it. Another application is photographic film.
 

Nowadays PVA-based polymers are being used widely in additive manufacturing. For example, 3D printed oral dosage forms demonstrate great potential in the pharmaceutical industry. It is possible to create drug-loaded tablets with modified drug-release characteristics where PVA is used as a binder substance. Medically, it may also used as the embolic agent in a Uterine Fibroid Embolectomy (UFE) 

Polyvinyl acetals are prepared by treating PVA with aldehydesButyraldehyde 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.
Preparation 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,[3] 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:

[CH2CH(OAc)]n + C2H5OH → [CH2CH(OH)]n + C2H5OAcThe properties of the polymer are affected by the degree of transesterification. 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.
 
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 resistant to oil, grease and solvents. It has high tensile strength and flexibility, as well as high oxygen and aroma barrier properties. However, these properties are dependent on humidity: water absorbed at higher humidity levels acts as a plasticiser, which reduces the polymer's tensile strength, but increases its elongation and tear strength.

Safety and environmental considerations


PVA is widely used, thus its toxicity and biodegradation are of interest. Solutions containing up to 5% PVA are nontoxic to fish. It biodegrades slowly。

Contáctenos

Persona de contacto: Yani Zhang

Empresa:Qingquan brand

Dirección:undefined, undefined, China,

A,

Yani Zhang < Qingquan brand >
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