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Polyvinyl Alchohol fiber is with Polyvinyl Alchohol as raw materials of synthetic fiber spinning. The fiber obtained by formaldehyde treatment of vinyl alcohol acetal fiber, vinylon Chinese said, internationally known Vigny lun. Low molecular weight Polyvinyl Alchohol as raw material by spinning fiber is soluble in water, soluble in water of Polyvinyl Alchohol fiber. Polyvinyl Alchohol fiber generally does not have the necessary water resistance, little value in practical application. Polyvinyl formal fiber with soft, warm characteristics, especially the moisture absorption rate (up to 5%) in synthetic fiber in various varieties is relatively high, so it is called synthetic cotton, but the poor heat resistance, softening point is only 120 ℃.
The polymerization of vinyl acetate:
Vinyl alcohol free and extremely unstable, can not exist alone, so to obtain the practical value of Polyvinyl Alchohol, usually with vinyl monomer polymerization and alcoholysis and hydrolysis, made of Polyvinyl Alchohol.
1. Vinyl acetate preparation:
At present, the vinyl acetate synthesis is mainly acetylene and ethylene method.
1). Acetylene method:
Acetylene method with acetylene and acetic acid as raw materials, at about 200 ℃, pressure to the gas to the catalyst of zinc acetate supported on reaction of vinyl acetate with active carbon and so on.
2). Ethylene method:
Ethylene law to ethylene and acetic acid as raw materials, using palladium gold catalyst, potassium acetate or sodium acetate as catalyst, activated alumina or silica gel as the carrier, in more than 100 ℃, pressure reaction of acetic ethylene.
2. Vinyl acetate preparation:
Vinyl susceptible to free radical polymerization. Under the action of the initiator, vinyl acetate polymerization conditions can occur in slow and under. Preparation of Polyvinyl Alchohol fiber is using poly vinyl acetate, usually using methanol as solvent by solvent polymerization.
The preparation of Polyvinyl Alchohol:
At present the production of Polyvinyl Alchohol fiber is poly vinyl acetate in methanol or sodium hydroxide under the action of alcoholysis reaction.
The polymerization of vinyl acetate:
Vinyl alcohol free and extremely unstable, can not exist alone, so to obtain the practical value of Polyvinyl Alchohol, usually with vinyl monomer polymerization and alcoholysis and hydrolysis, made of Polyvinyl Alchohol.
1. Vinyl acetate preparation:
At present, the vinyl acetate synthesis is mainly acetylene and ethylene method.
1). Acetylene method:
Acetylene method with acetylene and acetic acid as raw materials, at about 200 ℃, pressure to the gas to the catalyst of zinc acetate supported on reaction of vinyl acetate with active carbon and so on.
2). Ethylene method:
Ethylene law to ethylene and acetic acid as raw materials, using palladium gold catalyst, potassium acetate or sodium acetate as catalyst, activated alumina or silica gel as the carrier, in more than 100 ℃, pressure reaction of acetic ethylene.
2. Vinyl acetate preparation:
Vinyl susceptible to free radical polymerization. Under the action of the initiator, vinyl acetate polymerization conditions can occur in slow and under. Preparation of Polyvinyl Alchohol fiber is using poly vinyl acetate, usually using methanol as solvent by solvent polymerization.
The preparation of Polyvinyl Alchohol:
At present the production of Polyvinyl Alchohol fiber is poly vinyl acetate in methanol or sodium hydroxide under the action of alcoholysis reaction.
stevia - 16. Dez, 07:28
