CM8001

Styrofoam consist of mostly air and when dissolves in acetone, the polymer chains are able to slide around each other which in turn results in the release of air bubbles that are trap in the foam. As the acetone evaporated leaving the solid behind, this solid no longer contains air bubbles thus making it much denser.

a) LDPE is very fragile compared to HDPE. This is because LDPE consist of mostly amorphous structure that are arrange disorderly and hence making LDPE more softer and low resistance to being cut. The stronger, stiffer, more heat resistant and more flexible at lower temperature HDPE makes it more suitable compared to LDPE.

b)HDPE region of crystallinity is high and as they are arrange in orderly manner, they are more denser and stronger. Thus, successful in this application.

No, it does not happen. Plastic had weak but extensive dispersion forces which allow the molecules to slip pass one another hence allowing the plastic to stretch. Paper on the other hand is produce from cellulose. The multiple hydroxyl group from 1 chain form hydrogen bond with oxygen atom on a neighboring chain. It holds the chains firmly together side by side resulting in stiffness.

a) i.Stable and durable
ii.Upon disposal should be easily broken down
iii.Non-toxic
iv.Strong carbon backbone

b) For hard contact lenses: Polymethyl methacrylate (PMMA)
For soft contact lenses: Polyhydroxyethyl methacrylate (PHEMA)
The properties include transparent, flexibility, tough and hydrophilic.

c)For hard, it is rigid and not very comfortable. Also, it does not allow oxygen to pass directly to cornea. For soft, it is hydrophilic, soft and flexible.