Expanded Polystyrene Foam
Expanded polystyrene foam is an aromatic polymer. Polystyrene is one of the extensively used plastic. Expanded polystyrene foam has some desirable properties. It is extremely light and buoyant. It works as good insulator against sound and heat. It is used as building material, and can be cast into various molds. Polystyrene was discovered by Eduard Simon in 1839 in Berlin Germany.
Polystyrene is one of the widely used plastic. It is a polymer made up from monomer styrene. Styrene is aromatic monomer where as polystyrene is aromatic polymer. Polystyrene in its purest form is colorless, hard plastic with restricted flexibility. It is solid at room temperature but flows when heated above glass transition temperature and again becomes solid after cooling. Polystyrene can be transparent or can be given different colors. Expanded polystyrene foam is made up of mixture of 90-95% polystyrene with 5-10% of gaseous blowing agent. Solid plastic is expanded into foam with the use of heat.
Virgin unexpanded polystyrene beads which consist oxygen is expanded to produce expanded beads. Expanded polystyrene foam of size same as expanded beads is then obtained. Polystyrene foam pieces are exposed to pentane gas. These exposed pieces are then combined to form mixture which almost has 50%foam pieces by weight. This mixture is then casted into moulds .Heat and pressure is applied to produce final product. Pentane gas treatment creates fusion, final product is of high structural integrity and durability.
Hot wire is used in cutting polystyrene and giving shape. These hot wire cutter are made of taut length of wire generally nichrome. Hot wire is heated in such a way that it can vaporize the foam next to it. Foam actually get vaporized before wire is touched which results in fine smooth cuts. Traditional cutter can also be used for cutting polystyrene. For performing this task without ruining the sides, blade needs to be dipped in water then cutting should be done at angle of thirty degree. This procedure needs to be repeated several times for good results. Expanded polystyrene foam is biodegrade but its chemically inert feature makes it more stable fill material.
Polystyrene is economical and is used for plastic cutlery, assembly kits, cd cases, and various other things where a rigid plastic with color variety is required. Expanded polystyrene is also used for disposable cups. Use of expanded polystyrene is very cost effective it requires less energy.