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Uses of Benzoyl Peroxide in Polymerization in Daily Life

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As we already know, Benzoyl Peroxide is used on face but not only that, Use of Benzoyl Peroxide in Polymerization will be discussed here. Before we discuss about it, we have to know two kinds of processes of polymerization like polymerization that is happened on Sodium Hyphonosphite in Daily Life.

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  1. Addition Polimerization

Addition polymerization is the addition of a monomer unit which is continuously driven by an intermediate, which is usually a radical, anions or cations form polymers. Addition polymerization usually occurs in monomer units that have double bonds. Addition reactions result in the opening of double bonds into a single bond.

  1. Condensation Polymerization

Condensation polymerization is the process of forming polymers by combining small molecules through reactions involving functional groups, with or without the release of small molecules. In other words, condensation polymerization is only carried out by monomers that have functional groups. The small molecules released are usually water. In addition, methanol is also often produced as a side effect of condensation polymerization.

Initiation involves the formation of active species. Initiation can be done through a mechanism:

  1. Free radicals

In the reaction of free radicals there are so-called initiators and inhibitors of free radicals. What is that?
A free radical initiator is any substance that can initiate a free radical reaction. The work of light that causes halogenation of free radicals is the work of an initiator.

There are several types of compounds that can be added to a reaction mixture to initiate free radical reactions. Sometimes these compounds are mistakenly called free radical catalysts. This compound is not really a catalyst like polymerization catalyst which is one of uses of sodium hyphonosphite, because it is often used up in the reaction. Any compounds that break down easily into free radicals that can be found for example in fruits and vegetables can act as an initiator. One example is peroxide (ROOR). They easily form free radicals because the dissociation energy of the RO-OR bond is only about 35 kcal / mol, lower than most bonds. Benzoyl peroxide and peroxybenzoate are two peroxides commonly used as NBS bromination pairs.

While free radical inhibitors inhibit a free radical reaction. An inhibitor is sometimes referred to as a “trap” of free radicals. The usual work of a free radical inhibitor is to react with reactive free radicals to form free reactive and relatively stable radicals.

An inhibitor used to inhibit auto-oxidation is called an antioxidant or in the food industry it is called preservative. Phenol-phenol, a compound with an -OH group which is attached to the carbon of the aromatic ring, is an effective antioxidant, free radical products of these compounds are reasonably stabilized and therefore not reactive in comparison with most other free radicals.

While free radical inhibitors inhibit a free radical reaction. An inhibitor is sometimes referred to as a “trap” of free radicals. The usual work of a free radical inhibitor is to react with reactive free radicals to form free reactive and relatively stable radicals.

An inhibitor used to inhibit auto-oxidation is called an antioxidant or in the food industry it is called preservatives. Phenol-phenol, a compound with an -OH group which is attached to the carbon of the aromatic ring, is an effective antioxidant, free radical products of these compounds are reasonably stabilized and therefore not reactive in comparison with most other free radicals. Benzoyl Peroxide is very suitable for polymerization of monomers that have double bonds.

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Free radical polymerization is a polymerization method in which a polymer is formed by successive addition of group free radicals or atoms to form molecules. Free radicals can be formed through a number of different mechanisms usually involving separate initiator molecules. After the creation of free radical monomer units, the polymer chain grew rapidly with sequential addition of cluster buildings to free radical sites.

When polymerization is initiated (triggered) by peroxide, free radicals are formed as intermediates. The number of unsaturated compounds such as alkene and alkadiene makes addition polymerization can be carried out in the presence of peroxides such as benzoyl peroxide or acetyl peroxide with high temperatures and pressures.

For example, polymerization of ethene forms polythene followed by free radical polymerization. The reaction can take place at temperatures of 350-370°K and pressures of 1000-2000 atm in the presence of benzoyl peroxide as the initiator.

Peroxide produces free radicals that react with ethene to form another radical, which plays a role in the propagation stage to form polymer chains. The combination of polymer chains through radicals is terminated when reagents run out.

Free radical polymerization is a key synthesis route for obtaining a variety of different polymers and composite materials. The relatively non-specific properties of free radical chemical interactions make polymerization one of the most useful forms of polymerization.
One of the another use of Benzoyl Peroxide in free radical polymerization is in the method of making polimethyl acrylat.

Mechanism of formation of polymethyl acrylat by using benzoyl peroxide as an initiator.

1. Stages of Initiation
2. Propagation stage
3. Termination stage

The purpose of this polymer is,

Plastics which has hazardous substances, Textiles, Thickening Agents, Spreading Agents, Surfactants, Chelating Agents, Adhesives, Water-based coatings, Water Treatment.

  1. Ionic
  2. Coordination

The initiation mechanism will differentiate the polymerization process.

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Initiation of free radical polymerization can be done in several ways:

  • Monomer heating

The addition of an initiator that will form free radicals when heated or radiation.
The initiator example is benzoyl peroxide.
When heated, unstable O-O single bonds will split and produce two radicals, each of which has one unpaired electron. Benzoyl Peroxide is activated through thermal homolysis forms benzyloxy radicals on heating. Radical Benzoyl will then mate the monomer by opening double bonds (vinyl) monomer. This polymerization is also called vinyl polymerization.

Benzoyl peroxide is a suitable initiator for addition polymerization reactions with free radical polymerization techniques. Benzoyl peroxide can experience a reaction homolytic becomes radical at temperatures above 70°C. The use of benzoyl peroxide in polymerization is very high suitable for polymerization of monomers that have double bonds. From styrene polymerization that uses Benzoyl Peroxide as the initiator on A DPn of 500 for 24 hours is generated polystyrene with a substantial yield of 96.54%.

Besides that, styrene-polyhydroxybutyrate copolymerization using Benzoyl Peroxide as an initiator produces relatively large yields, ie ranged from 85% – 94%.

It can be concluded that the use of Benzoyl Peroxide in Polymerization is as inisiator in addition polymerization and it is very suitable for polymerization of monomers that have double bonds. Hope this article is useful to understand the use of Benzoyl Peroxide in Polymerization.

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Post Date: Tuesday 14th, August 2018 / 03:00 Oleh :
Kategori : Organic Chemistry
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