CM8001

Acetone dissolves the polymer, allowing the gas of the foaming agent to escape. The polymer collapses on itself and becomes more dense because the gas has removed.

a) LDPE is soft, stretchy, transparent and not very strong. Since LDPE is branched. its surface are available for contact between the molecules are weaker. Hence, the vanderwaals forces between the molecules are weaker.

b) Linear LDPE has long linear chains. Hence, the the surface area available for contact between the molecules are stronger. Hence, HDPE is usually associated with being rigid and not very flexible.

No it does not. As to plastics, the weak but extensive dispersion allow for the molecules to slip pass one another allowing the plastics to stretch and neck. This is unlike paper.

a) Non-toxic, lack of solubility, lack of reactivity and inexpensive.

b) Several types of contact lenses are made with different types of polymers. Polymers include polymethyl methacrylate (PMMA), rigid gas polymers (RGP) and Polymacon. Desirable properties include being permeable to oxygen, non-toxic, comfortable to wear and inexpensive.

c) Hard contacts are made of PMMA which is a rigid non-gas permeable plastic. Soft lenses, that have replaced them, are made of silicone. They are flexible and allows oxygen to reach the eye. As such, soft lenses are more comfortable to wear.