What is the basic element in polymers
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All plastics have a similar construction principle
The term polymer (Greek poly "a lot", meros "particle") was coined in 1832 by Jöns Jacob Berzelius, who, while studying low molecular weight tartaric acids, discovered that chemical substances with the same chemical composition can have different physical properties. In 1833 he referred to substances with the same composition but different properties as isomers. In the case of different molecular sizes, he suggested using the term polymers as well. In the 1880s, for example, F. M. Raoult and J. H. van't Hoff found very high molar masses for rubber or starch using physical methods.
Nevertheless, it was still a long time before more precise knowledge about the structure of polymers was actually obtained. Most scientists doubted that there were really huge molecules here. Rather, the prevailing view was that a large number of small molecules literally agglomerate and thereby form what is known as a micelle structure. Hermann Staudinger's suggestion, made around 1920, that polymers "macromolecules" (Greek macros "large") led to intense, emotional discussions. By investigating polystyrene, cellulose, rubber and other substances, Staudinger proved his theory of large molecules.
- Plastics are man-made materials that consist of macromolecules (giant molecules) with organic groups. They are made from many small molecules (called monomers). We therefore also speak of polymers.
- Plastics mainly consist of the elements carbon (), hydrogen () and oxygen (). In addition, nitrogen (), sulfur (), chlorine () and fluorine ().
I. Chain Macromolecules
If monomers are lined up linearly (i.e. without branching), as shown above, one obtains macromolecules that form chains: the same or different building blocks can be imagined as chain links, which keep recurring. The molar mass of these giant molecules is between 8,000 and 10,000,000 g / mol. This means that up to several hundred thousand building blocks can be linked to form one molecule. These chain-shaped macromolecules are found in so-called thermoplastics (Greek thermos "warm", plasso "form") plastics that melt when heated.
II. Macromolecules can also be crosslinked
In addition to the chain-like macromolecules - depending on the choice of monomers - crosslinked macromolecules can also arise. Depending on the strength of the crosslinking, plastics are created with different properties. Soft rubber material has little cross-linking - it is elastic. A socket, on the other hand, consists of a strongly networked material which is very durable even at high temperatures. We therefore also speak of elastomers (elastic = stretchable) and thermosets (thermosets) (Latin. durus "hard").
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