Thermosetting Plastics

GROUP -8,MEMBERS-TEJASVIN,SUSHANT,AVIRAL,PUNEET & LAAKSHI

A thermosetting plastic, also known as a thermoset, is ploymer material that irreversibly cures. The cure may be induced by heat, generally above 200 °C through a chemical reaction, or suitable irradiation. Thermoset materials are usually liquid or malleable prior to curing and designed to be molded into their final form, or used as adhesives. Others are solids like that of the molding compound used in semiconductors and integrated circuits (IC). Once hardened a thermoset resin cannot be reheated and melted to be shaped differently. Thermosetting polymers may be contrasted with thermoplastic polymers which are commonly produced in pellets and shaped into their final product form by melting and pressing or injection molding.

MADE BY-Aviral Grover

Thermosetting

The curing process transforms the resin into a plastic or rubber by a cross-linking process. Energy and/or catalysts are added that because the molecular chains to react at chemically active sites linking into a rigid, 3-D structure. The cross-linking process forms a molecule with a larger molecular weight, resulting in a material with a higher melting point. During the reaction, the molecular weight has increased to a point so that the melting point is higher than the surrounding ambient temperature, the material forms into a solid material.

PROCESS OF FORMATION

SUSHANT YADAV

Uses of thermosetting plastics

The most familiar use of thermosetting plastic is heat-resistant handle on metal cookware. It is also used for appliance bottle caps, knobs and handles and dinnerware. Thermosetting plastics retain their shape and strength even when heated.

They are used for many things such as kitchen utensils and also for things such as light fittings.

LAAKSHI

Advantages: convient, reusable, and you don't have to wash dishes/run your dishwasher. It is extreme versatility and low cost of manufacturing. Plastic can be molded to limitless forms, and is relatively cheap to produce. Disadvantages: Hurts the environment. That it does not decompose, and must be recycled to prevent build up of waste

SUSHANT YADAV

Structure of Thermosetting Plastics

Thermosetting polymers have their chains cross linked by covalent bonds .

The starting materials are placed into a mould to form the desired shape.

The polymer is then heated and chemical reactions occur to form the cross links between the chains.

The resulting three dimensional solid structures cannot then be changed. Further heating will not cause the polymer to soften, melt or change shape.

PROCESS OF TSP

Tejasvin

Properties of Thermosetting Plastics

Thermoset materials are generally stronger than thermoplastic materials due to this three dimensional network of bonds (cross-linking),

They are also better suited to high-temperature applications up to the decomposition temperature.

They are more brittle. As their shape is permanent, they tend not

to be recyclable as a source for newly made plastic.

Tejasvin

SOME EXAMPLES

o BAKELITE and MELAMINE

o 1. Bakelite is a poor conductor of heat & electricity.

o 2. Melamine resists fire and can tolerate heat better than other plastics.

puneet