CM8001

After dissolving the Styrofoam packing peanuts into acetone, the styrofoam will gather together, condenses and lose their air pockets. Thus, it will become denser.

(a) HDPE is more resistant to chemical impact and stress while LDPE being branched will have limited resistance.

(b) Good balance between flexibility and rigidness.

Interactions in plastic are weaker, they are arranged in a way that they can slide across each other in their layers. Stretching it.

Interactions in the paper are different, they do not have similar properties, hence, they will just break and no stretch.

a. (1) Chemical resistance – Bio-compatible
(2) Flexibility – depending on the use of the material, chemical properties should be different (e.g. bone vs heart valve)
(3) Pore size that only allows water vapour to escape but does not allow for water vapour to enter
(4) Will not degrade or release harmful substances at body temperature – Non-toxic

b. Polymethyl methacrylate (PMMA). Properties that are desirable includes soft, transparency and lightweight.

c. Hard – Polymethyl metha crylate PMMA
Soft – Silicone based – PHEMA – poly hydroxyethyl metha crylate
Soft lenses contain more water than the hard lenses.
Soft lenses tear more easily than hard lenses.