CM8001

Since styrofoam is made with foaming agents, the solubilisation of styrofoam in acetone releases the gas inside styrofoam. This allows the styrofoam to collapse on itself and become more dense.

a. Branched LDPE is too weak for such use.

b. Linear HDPE have monomers that line up in a way that allows it to have the required strength. By using a thin layer of HDPE, we can ensure that flexibility is also achieved.

No it does not. When plastic is stretched, the molecules are allowed to align itself in parallel to each other and in the direction of the pull. This change in conformation is irreversible and if the stretching persists, the plastic will tear. In a piece of paper, such significant stretching does not occur due to the rigidity of the bonds holding the cellulose molecules together. This rigidity does not allow the molecules within cellulose to easily change conformation and align with each other.

a. Non-reactive, non-toxic, cheap and easy to implant.

b. There are more than one type of polymer used to make contact lenses including polymethyl methacrylate (PMMA), Kolfocon, Polymacon etc. Desirable properties include non-toxicity, low-cost, permeability to oxygen and comfortable for wearing.

c. Hard contact lenses are usually made from PMMA which is rigid and non-gas permeable while soft contact lenses, usually made from Polymacon, are oxygen-permeable and flexible. These two properties of soft contact lenses make them more comfortable for wearing.