Types of polymerization , Chemistry

Assignment Help:

Types of polymerization 

Sol. Types of polymerization: polymerization is a process in which the joining together of many small molecules to form very large molecule called polymer. Polymers are formed in different ways:

1 Addition or chain reaction polymerization: monomaniac units contain one or more double bonds which by intermolecular rearrangement may provide the molecule bifunctionality.

 2 condensation or step reaction polymerization: in condensation polymerization reaction take place in step wise manner and the polymer build up is slow. Step reaction polymerization reactions are mostly accompanied by the elimination of small molecules.

3 Ionic Polymerization mechanisms: it involves an attack on the electron pair of the monomer either by a positive or negative ion. Ionic polymerization mechanism is of two types.

(1)                         Cationic mechanism: in this initiation is done by a proton and the propagation carried out by a harmonium ion. Examples of monomers that can undergo cationic polymerization are methyl viny1 etc.

(2)                         Anionic mechanism: in this the attack on the electron pair of the monomer is done by an anion. The harmonium thus formed now propagates the chain growth by attack in the second monomer unit. Alkali metal amides alkaloids and hydroxides are used as initiators monomers capable of undergoing anionic polymerization include butadiene isoprene styrene acrylonitrile etc.

4 Coordination polymerization or Ziegler Natta polymerizations: in such polymerization reactions especially of olefins and dines are catalyzed by organ metallic compounds. The first step in this process in the formation of a monomer catalyst complex between organ metallic compound and the monomer.

 

 


Related Discussions:- Types of polymerization

Periodic table and periodicity of properties, alkali metals belong to s-blo...

alkali metals belong to s-block in the periodic table.why?

Chemical properties proteins - salt formation, Chemical Properties Proteins...

Chemical Properties Proteins - Salt formation (i) Salt formation : Due  to  existence of  both -NH 2 and -COOH groups in proteins, they make salts along with acids and bases.

Benzaldehyde, Preparation of benzaldehyde by etard''s reaction

Preparation of benzaldehyde by etard''s reaction

Show the extraction of oxygen, Q. Show the Extraction of Oxygen? Oxygen...

Q. Show the Extraction of Oxygen? Oxygen is separated from air on a large scale by the fractional distillation of liquid air. It is obtained as a by-product along with hydrogen

Electronic configuration exhibits, 3d 10 4s0 electronic configuration exhi...

3d 10 4s0 electronic configuration exhibits by; (1) Zn ++                                (2) Cu ++                          (3) Cd ++                      (4) Hg ++

Write the structure of teflon, Write the structures of monomers used in the...

Write the structures of monomers used in the preparation of: a. Teflon b. PMMA

Thermodynamics, Given that dH for the reaction is -92.2 kJ mol-1, which is ...

Given that dH for the reaction is -92.2 kJ mol-1, which is larger, the total bond dissociation energy of the reactants or the total bond dissociation energy of the products?

Boyles law, 2 applications of boyles law in the field of engineering

2 applications of boyles law in the field of engineering

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd