What is meant by radical polymerization?
A free Radical Polymerization is a polymerizing approach by which successive addition of free radicals takes place to form a polymer unit. It is a type of chain-growth polymerization, with a cationic, anionic and coordination polymerization.
What is radical chain-growth polymerization?
3.1 Free-Radical Chain-Growth Polymerization Process. Polymerizations by free-radical mechanism are typical free-radical reactions. That is to say, there is an initiation, when the radicals are formed, a propagation, when the products are developed, and a termination, when the free-radical chain reactions end.
What do you mean by isotactic syndiotactic and atactic polymer?
The key difference between atactic isotactic and syndiotactic polymer is that the atactic polymers have their substituents in a random manner and isotactic polymers have their substituents in the same side, whereas the syndiotactic polymers have their substituents in an alternating pattern.
What is radical chain-growth?
Another reaction that diverts radical chain-growth polymerizations from producing linear macromolecules is called chain transfer. As the name implies, this reaction moves a carbon radical from one location to another by an intermolecular or intramolecular hydrogen atom transfer (colored green).
What is radical or vinyl polymerization?
Free radical polymerization (FRP) is one of the most important synthesis routes for obtaining vinyl polymers. The relatively non-specific nature of the free radicals towards vinyl and other unsaturated monomers makes FRP one of the most versatile polymerization methods.
What is the difference between atactic and isotactic polypropylene?
Atactic polypropylene is a soft, rubbery polymer, while isotactic polypropylene is strong and hard with excellent resistance to stress, cracking, and chemical reaction. Syndiotactic polypropylene has only recently been made on a large scale. It is somewhat softer than the isotactic polymer, but also tough and clear.
What is atactic polymers?
An atactic polymer is defined as a linear polymer containing asymmetrically substituted carbon atoms in the repeating unit in the main chain, a planar projection of whose structure has the same substituents situated randomly to one side or the other of the main chain. From: Polyolefin Fibres, 2009.
What is backbiting in radical polymerization?
Chain transfer can also occur within a poymer (intermolecular chain transfer), for example from the terminal group to a location on the polymer backbone by hydrogen abstraction. This reaction is known as backbiting. The result is branching of the backbone.
What is allyl free radical?
An allylic radical is a resonance-stabilized radical in each of the two resonance forms of which the unpaired electron is on an allylic carbon. The lightest allylic radical 1 is called the allyl radical.