Answer to Question #126641 in Organic Chemistry for Kamli Ramli

Question

Why glass transition temperature changes in substantial polyvinyl alcohol? Or why the polymer having isolated functional group has changed glass transition temperature as compared to original polymer.

Answer 1

 glass transition temperature depands on these factors .

Pressure and free volume. Increase in pressure of surrounding leads to decrease in free volume and ultimately high Tg. Other factors like branching, alkyl chain length, bond interaction, flexibility of polymer chain, film thickness etc. also have significant impact on glass transition temperature of polymers.

Polyvinyl alcohol (PVA) is a water-soluble polymer with a glass transition temperature, Tg, of 80°C. Although its name implies a homopolymer structure, the structure of commercial PVA is a copolymer of vinyl alcohol and vinyl acetate .

due to change in above factor  glass transition temperature changes .