What is the polymerization of polystyrene?

Polystyrene is an addition polymer that results when styrene monomers interconnect (polymerization). In the polymerization, the carbon-carbon π bond of the vinyl group is broken and a new carbon-carbon σ bond is formed, attaching to the carbon of another styrene monomer to the chain.

How is polystyrene synthesized?

Polystyrene is created via the polymerization of styrene – a petroleum based, liquid hydrocarbon monomer. In this three-step synthesis, styrene is formed via the radical bromination of ethylbenzene and the elimination reaction of (1-bromo-ethyl)benzene.

What type of polymerization is initiated with the use of a free radical?

Free-radical polymerization (FRP) is a method of polymerization, by which a polymer forms by the successive addition of free-radical building blocks. Following its generation, the initiating free radical adds (nonradical) monomer units, thereby growing the polymer chain.

Which catalyst is used for free radical polymerization?

Radical Chain-Growth Polymerization When radical polymerization is desired, it must be started by using a radical initiator, such as a peroxide or certain azo compounds. The formulas of some common initiators, and equations showing the formation of radical species from these initiators are presented below.

Is polystyrene a homopolymer or copolymer?

Polystyrene is typically (but not always) a homopolymer meaning that it is composed only of the monomer styrene in combination with itself. Depending on the type of PS it could be classified as a “thermoplastic” or a “thermoset” material.

What is the difference between Styrofoam and polystyrene?

Styrofoam is a form of polystyrene. The key difference between polystyrene and Styrofoam is that the polystyrene is a form of synthetic aromatic hydrocarbon polymer whereas the Styrofoam is a commercial brand of polystyrene.

What is polystyrene made out of?

Polystyrene is formed when styrene meets with pentane and is made from a rigid cellular plastic containing an expansion agent. Styrene has at times been labelled as a “known carcinogen”, however extensive research has found that unless the exposure is extremely high, styrene will not cause any adverse health effects.

Which compound is used as free radical terminator?

di-tert-butyl peroxide.

What is free radical polymerization example?

For example, 40 to 45 percent of all polymers and synthetic rubbers are produced via a free radical polymerization process. This includes polystyrene, poly(methyl methacrylate), polyvinyl acetate, polyvinyl chloride, polybutadiene, polychloroprene and polyethylene among many other large volume polymers and elastomers.

What is a free radical How are free radicals important in the formation of polyethylene?

Free radicals are important in the production of polymers such as polyethylene because they behave as catalysts to the polymerization reaction….

Is polystyrene linear or branched?

Polymers. Addition polymers such as polyethylene, polypropylene, poly(vinyl chloride), and polystyrene are linear or branched polymers with little or no cross-linking. As a result, they are thermoplastic materials, which flow easily when heated and can be molded into a variety of shapes.

Is polystyrene a thermoplastic?

Polystyrene is a synthetic polymer made from styrene monomer, which is a liquid petrochemical. It is a thermoplastic polymer which softens when heated and can be converted via semi-finished products, such as films and sheets, into a wide range of final articles.

What makes the polymerization of styrene so easy?

The relative ease of polymerization of styrene can be explained by resonance stabilization of the growing polystyrene in its transition state. The predominant and most economical polymerization process of styrene is thermal bulk polymerization at 130 to 140°C which is initiated by heat alone. Suspension and solution polymerization are also common.

Which is the most common method of polystyrene synthesis?

Commercial polystyrene is mostly synthesized by bulk, suspension or solution polymerization of ethylbenzene (styrene). The most common method is free radical polymerization, using benzoyl peroxide as initiator. However, other initiators such as redox systems and azo compounds can be used as well to start the polymerization.

Which is the most common method of free radical polymerization?

The most common method is free radical polymerization, using benzoyl peroxide as initiator. However, other initiators such as redox systems and azo compounds can be used as well to start the polymerization. The reaction is exothermic, and thus the monomer-polymer mixture has to be cooled.

What kind of reactor is used to polymerize styrene?

In the first stage, the styrene is polymerized in a stirred tank reactor, the so-called pre-polymerizer. Only a low conversion is achieved. The mixture of dispersed polymer in monomer is then transferred to a tubular thin-film reactor.