Polyvinyl Alcohol

Polyvinyl Alcohol Uses, Properties and Applications

Introduction 

PVA full form is polyvinyl alcohol. Polyvinyl alcohol is a man-made or synthetic polymer. PVA polymer molecules contain vinyl and alcohol groups. It is a very useful polymer due to its adhesive properties. PVA is water-soluble, crystalline and flammable in nature. The presence of alcohol in it makes it flammable. 


Polyvinyl alcohol formula (Structural)

Polyvinyl meaning – Word poly means ‘many’ and vinyl is ‘ethenyl’ functional group. The formula of vinyl is -CH=CH2. When we remove one hydrogen atom from the ethylene or ethene molecule (H2C=CH2) we get a vinyl group. 

PVA structure or Polyvinyl alcohol structure

PVA monomer unit is vinyl acetate. It means, it is formed by the polymerization of vinyl acetate. Vinyl acetate formula is H3C-CO2-CH=CH2. PVA is not prepared by direct polymerization of vinyl acetate. Instead, it is prepared by hydrolysis of polyvinyl acetate (PVAc) through alcohol (generally methanol) in presence of an alkaline catalyst. 

Polyvinyl acetate                           Polyvinyl alcohol


Properties of PVA 

Physical properties of PVA – 

  1. PVA shows high tensile strength and flexibility. 

  2. It is soluble in water and has no odor. 

  3. PVA molecular weight or polyvinyl molecular weight ranges between 26,000-30,000. 

  4. Its melting point is 185°C

  5. It is insoluble in organic solvents but slightly soluble in ethanol. 

Chemical properties of PVA – 

  1. Polyvinyl alcohol can react with butyraldehyde and formaldehyde. 

  2. It is atactic type material and resistant to oil and grease. 

Polyvinyl Alcohol Uses

PVA polymer is used in many fields. It is used as the main component in many drugs. Many of its applications are based on its adhesive property. PVA is a type of synthetic adhesive. PVA is used as PVA glue in many fields. Meaning of PVA glue is a glue or fixative made up of polyvinyl alcohol. 

                 

PVA glue uses-

PVA glue is soluble in water and used as emulsions also. It is mainly used for fixing porous material. It is used for gluing wood, paper, and cloth. 

What is PVA adhesive? & How to make PVA glue?

PVA glue or PVA fixative is also known as PVA adhesive. PVA glue can be prepared by a simple method. To make PVA glue, simply take 200g of PVA and dissolve it in water to make 1000ml of solution. Now heat this solution and bring to boil. Continue simmering it for half an hour. After half an hour, remove the solution from heat and cool it down. PVA glue is ready. 

PVA glue can be removed by PVA remover. Many PVA removers are available in market. PVA glue from fabric can be easily removed by using hot water as PVA remover, as PVA is water soluble. 

Is PVA glue toxic? 

PVA is widely used as glue. PVA glue is non-toxic. Although research is ongoing on the subject whether long term use of PVA glue harmful or not, researches have shown that oral administration of PVA is harmless. So, use of PVA as glue should also be harmless. 

Use of PVA as Polyvinyl fabric- PVA is a very good absorbent. This property of PVA is very useful in the textile industry. That’s why PVA is used in the textile industry. PVA fabric can dry well. 

PVA fabric 

Use of PVA as polyvinyl alcohol film – PVA films are used in packaging of different materials such as detergents, chemicals, disinfectants etc. in many industries. As PVA is water soluble, PVA packaging material is biodegradable. 


PVA film used for packing 

How to make polyvinyl alcohol film?

Polyvinyl alcohol film is also known as polyvinyl sheet. Polyvinyl alcohol film can be made by PVA solution. PVA solution is prepared by dissolving PVA in water. PVA sheets are very useful in packaging. The main advantage of PVA film is that it is environment friendly, as it is biodegradable. 

Polyvinyl alcohol hazards – Some drugs of PVA can cause some allergic reactions in eyes and skin. But mostly PVA is non-hazardous. It is biodegradable and environment friendly. It is debatable whether PVA’s long-term use in packaging or as a glue is harmful for humans, as research is still going on this.