CM8001

Styrofoam is made up of polystyrene foam. When polystyrene dissolves in acetone, air in foam is released, polymer rearranged causing it to look like massive quantity of material is being dissolved into a small volume of liquid.

a. LDPE has low tensile strength so it bends easily.

b. HDPE has less branching, resulting in more molecular forces of attraction and higher tensile strength.

No, intermolecular forces (eg. Van Der Waals and Hydrogen bonds) between chains of plastic polymers are not very strong and can be overcame easily allows chains to slide past each other when stretched.

Interaction in paper are different and much stronger as it does not have same chemical properties as plastics.

a. – Non-toxic
– Capable of maintaining a good mechanical integrity (stable)
– Capable of controlled rate of degradation
– Pore size sufficient for water vapour to pass through but kept out water droplets
(expand and stretch to form a membrane)

b. Poly (Methylmethacrylate) (PMMA)
– Non-toxic
– Permeable to oxygen
– Comfortable
– Inexpensive
– Conform eye shape and easily cleaned

c. Hard => clarity, light weight
Soft => soft, flexible, permeable to oxygen, comfortable