Can anyone tell me why poly(ethelyne glycol) has a higher Tg than polyethylene?
Below some temperature they can no longer rotate
Does that mean C-O bonds don't rotate as freely as C-C bonds, maybe an inequality in the electronic character of the C and O atoms that causes stiffness?
The glass transition temperature is all about free rotation of the units along the chain.
Below some temperature they can no longer rotate - this is called the glass transition temperature.
The rotation depends upon many things
The size of the side groups
The components of the main chain
The polarity of side groups