CM8001

As acetone is an organic solvent. styrofoam is soluble in organic solvent such as acetone as acetone act as a lubricant between the polymers chain, allowing them to slide around each other. This cause the release of air bubble within the styrofoam, which makes the styrofoam denser after the evaporation of acetone.

a. HDPE is stronger than LDPE.
LDPE does not have sufficient strength to be use for surgical gloves.
b. Molecules of HDPE must line up in a way to produce the required strength.
For flexible-wire, the linear HDPE must be in thin liner for it to be flexible.

When we try to stretch a plastic bag, the weak but extensive dispersion forces allow the molecule to slip pass one another allowing the plastic bag to stretch and neck . the molecules aligned parallel to each other and in the direction of the pull.
when pull a piece of paper, the paper is torn.

a. strong, light weight un-reactive, easy to mould.
b. PMMA, transparent, flexible hydrophilic, unreactive
c. Hard- rigid, last for years, give good clarity to vision
Soft- cheaper, can be used for one day then disposed. more comfortable.