What is polymerisation ?

Question

science -1 std xth

Answer 1

In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains . There are many forms of polymerization and different systems exist to categorize them.

Answer 2

POLYMERIZATION IS THE TECHNIQUE BY WHICH A SINGLE MONOMER CAN BE MADE IN LONG CHAIN.

VERY GOOD EXAMPLE IS PROTEIN, IN WHICH AMINO ACID IS A MONOMER WHICH COMBINES TO FORM A POLYMER.

SINGLE TYPE OF MONOMERS OR VARIOUS TYPE OF MONOMERS CAN BE USED FOR POLYMERISATION.

n CH2 = CH2  -->  -(CH2-CH2)-n

   MONOMER          POLYMER

   (ETHYLENT)        (POLYEHTENE)

Answer 3

the joining of monomers to become a polymer.

a good simple example of this is seen with the simple sugar glucose, joining with other glucose molecules (bonds joining) to create a carbohydrate.  

Answer 4

Any process in which monomers combine chemically to produce a polymer. The monomer molecules — which in the polymer usually number from at least 100 to many thousands — may or may not all be the same. In nature, enzymes carry out polymerization under ordinary conditions to form proteins, nucleic acids, and carbohydrate polymers; in industry, the reaction is usually done with a catalyst, often under high pressure or heat. In addition polymerization, monomers are added successively to the reactive ends of a growing polymer molecule, similar to adding links to a chain; during the reactions, no by-products are formed. In condensation polymerization, growth of the polymer advances stepwise — monomers having reactive functional groups combine into larger molecules with their own functional groups; each reaction splits off a small molecule, often water, as a by-product.

Kalra

Answer 5

Polymerization is a process of reacting monomer molecules (small units) together in a chemical reaction to form three-dimensional networks or polymer chains.  Addition polymerisation, also called polyaddition or chain growth polymerization, is a polymerisation technique where unsaturated monomer molecules (carbon chains with no double bonds and all bonding sites filled with hydrogen atoms) add on to a growing polymer chain one at a time. Step-growth polymerization is a polymerization process that involves a chemical reaction between multifunctional monomer molecules. In a step-growth reaction, the growing chains may react with each other to form even longer chains. This applies to chains of all lengths. Thus, a monomer or dimer may react in just the same way as a chain hundreds of monomer units long. The most common class of step-growth polymerization is called condensation polymerization and the product a condensation polymer, because the chemical reaction by which the monomer molecules bond is often a condensation reaction that produces a small molecule byproduct. To find out lots more about polymerisation also spelled polymerization, go to this site:

http://en.wikipedia.org/wiki/Polymerizat...

Answer 6

when monomers combine to form a long chain is called polymerisation

Answer 7

A monomer is normally an organic simple compound like Ethylene [can be inorganic simple compounds like SiO2 also] which have the capacity to form long chain compounds called polymers.

Ethylyne gives polyethylene. In this reaction, the double bonds in ethylene will be reduced to a single bond.

nCH2=CH2 gives -[CH2-CH2]n-

This type of formation of a polymer is called addition polymerization.

C6H5OH + HCHO gives phenol formaldehyde polymer. In this one molecule of water is eleminated during the formation of the polymer called Bakelite. This type of formation of a polymer is called condensation polymerization.

Hence, polymerization is a process of combining monomers either through addition or condensation to give a huge molecule called polymer.

Answer 8

In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains. There are many forms of polymerization and different systems exist to categorize them.

Answer 9

In chemical compounds, polymerization occurs via a variety of reaction mechanisms which vary in complexity due to functional groups present in reacting compounds[4] and their inherent steric effects explained by VSEPR Theory. In more straightforward polymerization, alkenes, which are a relatively stable due to σ bonding between carbon atoms form polymers through relatively simple radical reactions; conversely, more complex reactions such as those that involve substitution at the carbonyl atom require more complex synthesis due to the way in which reacting molecules polymerize.[4]

As alkenes can be formed in somewhat straightforward reaction mechanisms, they form useful compounds such as polyethylene and polyvinyl chloride (PVC) when undergoing radical reactions,[4] which are produced in high tonnages each year[4] due to their usefulness in manufacturing processes of commercial products, such as piping, insulation and packaging. Polymers such as PVC are generally referred to as "singular" polymers as they consist of repeated long chains or structures of the same monomer unit, whereas polymers that consist of more than one molecule are referred to as "co-polymers".

Other monomer units, such as formaldehyde hydrates or simple aldehydes, are able to polymerize themselves at quite low temperatures (>-80oC) to form trimers;[4] molecules consisting of 3 monomer units which can cyclize to form ring cyclic structures, or undergo further reactions to form tetramers,[4] or 4 monomer-unit compounds. Further compounds either being referred to as oligomers[4] in smaller molecules. Generally, because formaldehyde is an exceptionally reactive electrophile it allows nucleophillic addition of hemiacetal intermediates, which are generally short lived and relatively unstable "mid stage" compounds which react with other molecules present to form more stable polymeric compounds.

Polymerization that is not sufficiently moderated and proceeds at an undesirably fast rate can be very hazardous. This phenomenon is known as Hazardous polymerization and can cause fires and explosions.

Answer 10

Polymerization is the combination of small molecules (monomers) into a single larger chain (polymer), either by condensation (where two molecules combine and a smaller molecule is removed), or addition, where the monomers add on to the end of the polymer chain.