explain the formation of polystyrene in with polymerization by addition method.
Answers
Answer:
Polystyrene is a polymer that can be prepared by a monomer addition process. The addition reaction is catalyzed by radical cations or anions, although the most common are the free-radical processes. In this experiment, a radical process with benzoyl peroxide as a radical initiator is used.......
Answer:
Addition polymerization is the successive addition of alkene monomers to one another. The addition reaction may occur by way of radical, cationic, or anionic intermediates. Condensation polymerization is a reaction that joins two functional groups such as an alcohol and a carboxylic acid and forms a second small molecule such as water.
Addition polymers are chain growth polymers because each intermediate adds another monomer unit one at a time. Condensation polymers are step-growth polymers because condensation may occur between two smaller molecular weight chains. Thus, the joining of oligomers results in a substantial increase in molecular weight in a single step.
Polyaddition
The polyaddition reactions are similar to polycondensation reactions because they are also step reactions, however, without splitting off low-molecular weight by-products. The reaction is exothermic rather than endothermic and therefore cannot be stopped at will. Typical for polyaddition reaction is that individual atoms, usually H-atoms, wander from one monomer to another as the two monomers combine through a covalent bond. The monomers, as in polycondensation reactions, have to be added in stoichiometric amounts. These reactions do not start spontaneously and they are slow. Polyaddition does not play a significant role in the production of thermoplastics. It is commonly encountered with cross-linked polymers. Polyurethane, which can be either a thermoplastic or thermosets, is synthesized by the reaction of multifunctional isocyanates with multifunctional amines or alcohol. Thermosetting EPs are formed by polyaddition of epoxides with curing agents, such as amines and acid anhydrides