- The foaming agent used during the polymerization process will make the styrofoam much bigger than their original size of the monomers. The bigger size is due to the polystyrene foam containing air. When dissolving styrofoam into acetone, the air inside is released so the solid remained after evaporation of acetone is much denser.
- (a) The branched LDPE has much weaker intermolecular forces between the branched polymers, which may be easily cut through by sharp tools. (b) Linear HDPE which contains linear polymers will have more surface area of polymer chains to form stronger intermolecular interactions, making the linear HDPE gloves have high resistance to being cut.
- Paper cannot be stretched and maybe broken. Paper is made of cellulose which is a polymer connected through covalent bonds. When these covalent bonds are broken, they cannot form again by themselves. On the contrary, plastic bags which is made of polymers interacting with each other by weak van der waals’ forces can be stretched because this intermolecular forces can be easily reformed as long as the polymers are close together.
- (a) Less toxicity to human body, good biocompatibility, lower corrosion rate, easy processing and workability (b) Polymethyl methacrylate (PMMA)- hard, Silicone hydrogels- soft (c) Hard contact lenses are not comfortable to wear, but they are more chemically inert, allowing them to be worn in more challenging environment than soft lenses. Soft lenses have high oxygen permeability and are comfortable to wear. The lenses can be hydrophobic and may make eyes dry when wearing it.
