Question

What is the effect of structure on the properties of a polymer?

Answer 1

1. Chain length: Longer chains raise strength, toughness, and glass-transition temperature, and reduce flow.
2. Branching: More branching reduces chain packing and crystallinity, lowering density and strength.
3. Crosslinking: Increased crosslinks give higher stiffness, hardness, insolubility, and thermal stability.
4. Crystallinity: Greater crystallinity increases density, melting point, and stiffness, while amorphous regions make materials more flexible.
5. Side groups/tacticity and orientation: Regular small side groups and aligned chains favour crystallinity; bulky or polar groups raise Tg.