CM8001

Styrofoam contains lots of air space, when it is dissolved in acetone, the air bubbles escape and the structure will change, result in denser structure.

a. Branching will cause the structure will be more rigid (brittle) thus it will be less flexible.

b. The layers of molecules can slide between each linear HDPE, therefore making it more flexible.

– The weak but extensive dispersion force allows the molecules to slip pass one another thus allowing it to stretch.

– As for paper, there is different interaction which does not allow sliding between molecules.

a. Non toxic, bio-compatible, non-biodegradable, lack of reactivity in body fluid

b. PMMA (Poly methyl methacrylate)
– Light weight
– Transparent
– Non-toxic
– Permeable to oxygen

c. Hard contact lens (PMMA) => rigid, non-gas permeable plastic
Soft (silicone) => flexible, allows oxygen to reach eyes
Due to those properties, soft lenses tend to be more comfortable.