CM8001

Acetone dissolve foaming agent in styrofoam where it evaporates. Foaming agents are removed too. Therefore PS is the denser substance. Styrofoam contains a lot of air. Dissolves the polymer –> Gas escapes –> molecules can rearrange into a more compact structure –> denser

a. Branched LDPE does not have a high resistance to being cut due to weak IMF. Therefore, it cannot be used for liners in surgical gloves. LDPE is flexible and not resistant to cut due to branched polymetric structure –> weak IMF

b. Linear HDPE is stronger than LDPE because there are higher surface of contact for intermolecular forces of attraction to occur. Thus HDPE is stronger.

It does not happen to papers as it does not have the structure to allow for dislocation motion of its atoms. Since dislocation motion does not happen, deformation does not happen. Dislocation motion = slipping of a group of bonded atoms along the dislocation plane. Polymer: % molecules –> IMF –> Weak forces of attraction –> broken and reformed quickly –> broken and reformed = stretchable
Paper: IMF stronger, cannot reform after being broken –> the attractive forces % the molecule becomes permanently broken and thus the paper is being torn and not stretchable.

a. Non toxic, non biodegradable, chemical resistent to rust, chemically stable, bio-compatible.
b. polymethylmethacrylate (Hard lenses)
hydro gels hydroxymethylmethacrylate (Soft Lenses)
contact lens have to be hydrophilic, allow oxygen transport to cornea. It must be soft so that it can fit the shape of the eye. It should also be flexible.
c. Hard lenses are difficult to adapt to, gas permeable, free of toxic chemicals and are more suited for people with high astig. Soft lenses are easier to wear because they are more flexible than hard lenses.