What is polyvinyl alcohol (PVA)?
What is polyvinyl alcohol (PVA)?
Polyvinyl alcohol, also known as PVOH, PVA, or PVAL, is a synthetic polymer that is soluble in water. It is effective in film forming, emulsifying, and has an adhesive quality.
How do you make polyvinyl alcohol from acetate?
Various indirect methods that involve alcoholysis (also called saponification or hydrolysis) of polyvinyl acetate are used to prepare polyvinyl alcohol. Preparation can be carried out by dissolving polyvinyl acetate in methanol or ethanol with alkaline or acid or acid catalyst and heating to precipitate the polyvinyl alcohol from the solution.
What is the global consumption of polyvinyl alcohol?
Worldwide consumption of polyvinyl alcohol was over one million metric tons in 2006. Larger producers include Kuraray (Japan, Europe, and USA) and Sekisui Specialty Chemicals (USA) but mainland China has installed a number of very large production facilities in the past decade and currently accounts for 45% of world capacity.
Does humidity affect the properties of polyvinyl alcohol?
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. PVA is widely used, thus its toxicity and biodegradation are of interest.
Polyvinyl alcohol (PVA) is one hydrophilic water-soluble synthetic polymer for electrospinning due to the presence of a hydroxyl group in its repeating unit, which makes it cross-linkable by means of its interconnected hydrogen bonding. Harekrishna Roy,
Is polyvinyl alcohol used as a concrete additive?
Dissolved Polyvinyl-Alcohol (PVA) has also been used as a concrete additive. A number of studies exist on the matter, in which the properties of PMC are explored. A review of the possible uses of PMC including structural applications can be found in [1], [2], [3].
What is the molecular structure of acetalized PVA?
Most commonly seen acetalized PVA is polyvinyl formal. Molecular structures of PVA and polyvinyl formal (Vinylon) are shown in Fig. 5.50. Figure 5.50. Molecular structures of polyvinyl alcohol and polyvinyl formal.
Does PVA have high solubility in water?
PVA possesses very high water solubility and therefore is usually not a choice for technical textiles unless water solubility is desired. Most commonly seen acetalized PVA is polyvinyl formal. Molecular structures of PVA and polyvinyl formal (Vinylon) are shown in Fig. 5.50.
