Several modified manufacturing methods of PVA film
发布时间 : 2020-11--10
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PVA film is a vinyl polymer that can be used by bacteria as carbon source and energy. Under the action of bacteria and enzymes, it can degrade 75% in 46 days. It is a kind of biodegradable polymer material and can be produced on a large scale by non-petroleum routes. Inexpensive, its oil resistance, solvent resistance and gas barrier properties are outstanding, and it has unique advantages in food and pharmaceutical packaging.
(1) Copolymerization modification, introducing weaker units into the main chain or side groups through copolymerization or polymer reaction, weakening the intramolecular and intermolecular forces of PVA, and lowering the melting point
(2) Blending modification, by adding a large number of polymers that can form hydrogen bonds with the hydroxyl groups in PVA, destroy the intermolecular forces of PVA, lower the melting point or increase the thermal decomposition temperature, such as sugar derivatives, collagen hydrolysates, etc.
(3) Post-reaction modification, by chemically modifying the hydroxyl groups on the PVA molecular chain, introducing structural units that can reduce the regularity of the PVA and increase the thermal stability, and improve the thermoplastic processing performance of the PVA.
(4) Plasticization modification. This method is simple and efficient. Many domestic and foreign researches on plasticization use water, inorganic salts, glycerin, polyols and their oligomers, caprolactam, alcohol amines and other single or compound plasticization modifications. It reduces the melting point of PVA and improves processing fluidity.
