Different Properties of Duroplatics and Thermoplastics
Duroplastics
Experiment:
20 g formaldehyde solution is mixed with 25 g aqueous solution of phenol and little liquor amounts in a glass beaker, and heated. The mixture begin to foam and thickens into a light yellow mass.
Explanation:
the substance formed is a phenolic resin (Bakellite, name after Bakeland, the discoverer of synthetic resins). Within a few days, the substance hardens. It is composed of many phenol molecules. These molecules are bound together (in the form of bridges between phenol molecules) by formaldehyde molecules. Several thousand phenol and formaldehyde molecules are interwoven in one Bakelite molecule. These form a spatial lattice, which accounts for the hardness and brittleness of the substance. Even gentle heating cannot change the spatial lattice of the molecule, so that the material cannot be deformed. The spatial lattice can be destroyed by heat only when chemical decomposition takes place, which means that the plastic is destroyed.
Thermoplastics
Experiment:
Liquid styrol is poured into a glass beaker. If a catalyst (reaction accelerator) is added in the ratio 1:10, a viscous mass forms at 200oC which addition in a little while. Filaments can be drawn from this mass.
Explanation:
The individual styrol molecules have combined to form gland molecules arranged like filaments. These are therefore also known as filamentary molecules. This process is called polymerization (polys – Greek: many, mares – Greek: part). This term expresses the fact that many identical parts have combined. The internal cohesion between molecules is mainly the result of physical forces.
Every time they are heated, the filamentary molecules become increasingly mobile with respect to each other, to the point where the material becomes a plastic fluid: when they are cooled again, the molecules reorganize themselves either in the form of long bundles (semi crystalline) or in a close mesh (amorphous, i.e. shapeless). The filamentary molecules can be oriented in such a way by stretching, that the longitudinal strength increases tenfold. This accounts for the great breaking strength in general are: Plastische Massen or simply Plaste in German and matleres plastiques in French.
Plastics are classified mainly with respect to their constituent substances.
Experiment:
20 g formaldehyde solution is mixed with 25 g aqueous solution of phenol and little liquor amounts in a glass beaker, and heated. The mixture begin to foam and thickens into a light yellow mass.
Explanation:
the substance formed is a phenolic resin (Bakellite, name after Bakeland, the discoverer of synthetic resins). Within a few days, the substance hardens. It is composed of many phenol molecules. These molecules are bound together (in the form of bridges between phenol molecules) by formaldehyde molecules. Several thousand phenol and formaldehyde molecules are interwoven in one Bakelite molecule. These form a spatial lattice, which accounts for the hardness and brittleness of the substance. Even gentle heating cannot change the spatial lattice of the molecule, so that the material cannot be deformed. The spatial lattice can be destroyed by heat only when chemical decomposition takes place, which means that the plastic is destroyed.
Thermoplastics
Experiment:
Liquid styrol is poured into a glass beaker. If a catalyst (reaction accelerator) is added in the ratio 1:10, a viscous mass forms at 200oC which addition in a little while. Filaments can be drawn from this mass.
Explanation:
The individual styrol molecules have combined to form gland molecules arranged like filaments. These are therefore also known as filamentary molecules. This process is called polymerization (polys – Greek: many, mares – Greek: part). This term expresses the fact that many identical parts have combined. The internal cohesion between molecules is mainly the result of physical forces.
Every time they are heated, the filamentary molecules become increasingly mobile with respect to each other, to the point where the material becomes a plastic fluid: when they are cooled again, the molecules reorganize themselves either in the form of long bundles (semi crystalline) or in a close mesh (amorphous, i.e. shapeless). The filamentary molecules can be oriented in such a way by stretching, that the longitudinal strength increases tenfold. This accounts for the great breaking strength in general are: Plastische Massen or simply Plaste in German and matleres plastiques in French.
Plastics are classified mainly with respect to their constituent substances.
