Silicones are water repellent , heat stable, and very resistant to chemical.
PLASTICS Plastics are Polymers Of Organic Compounds Or Resins that can be moulded Into any shape by the application of heat and pressure.
TYPES OF PLASTICS
Thermos Plastics Or Thermoplast
Thermosetting Plastics or Thermoset
A Plastic material that can be soften when heated with Pressure and can me remodeled into another shape.
EXAMPLE Poly Venyl Chloride
THERMOSETTING PLASTICS Have the property of becoming permanently hard and rigid when heated or cured. It cannot be softened or remoulded. The phenol resins and plastics were the original synthetic thermosetting materials
EXAMPLES BAKETIE FORMALDEHYDE
MECHANICAL PROPERTIES OF PLASTICS
The strength to weight ratio of plastics is higher than that of light metals.
Plastics Degrade at At high temperature.
Plastics are Good insulators.
Creep is an important property that it cannot withstand its own weight and undergoes change in shape.
GLASS TRANSITION TEMPERATURE (Tg)
A Thermoplastic which becomes an Elastomer (resembles a rubber) on heating to a particular temperature.
USES OF BAKELITE
Bakelite Called as “Material” OfThousands”has the following uses.
Bakelite was a Water and solvent resistant.
It is used in the Manufacture Of electrical Equipments.
It is used to make telephone, radio and TV cabinets.
USES OF FORMALDEHYDE
It is a resin used widely as glue, fire retardant and water repellant.
It Is Used In tanning industry and for treating various vegetable proteins to render them fibrous.
It Is Used For Moulding
It Is Used As A Laminating
It is used for making toys, radio, and TV parts.
It is used for making high frequency electrical insulators.
It is used for making models and so on.
POLY VINYL CHLORIDE
It brings water to our homes, covers our walls and floors, and does countless other important tasks
PVC is used in fluorescent light diffuser panels.
PVC is used in wiring and cable covering, shrink-on seals on medicine and food containers, shatter-proof bottles, protective clothing, life rafts, life jackets,
sporting goods,conveyor belts in
coal mines, non-slip flooring,
and foam cores of some
Nylon is popular for hosiery and is used to make track pants, shorts, swimwear, active wear, windbreakers, bedspread.
It is used in making ropes, clothes.
It is used to make gears and bearings.
It can also be made into
parachutes, combat uniforms,
tires and life vests, and in
fishing nets, umbrellas.
It is used in manufacture of sandwich bags, cling wrap, car covers, squeeze bottles, liners for tanks and ponds, moisture barriers in construction.
It is used in freezer bags, water pipes, wire and cable insulation.