Lecture

Cationic Polymerization: Synthetic Rubber

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In course

MSE-437: Polymer chemistry and macromolecular engineering

Know modern methods of polymer synthesis. Understand how parameters, which determine polymer structure and properties, such as molecular weight, molecular weight distribution, topology, microstructure can be controlled by proper choice of polymerization me ...

Description

This lecture by the instructor covers the process of cationic polymerization for the production of synthetic rubber, focusing on monomers like isobutylene and isoprene. It explains the challenges and advantages of radical versus ionic chain polymerization, detailing the initiation, propagation, and termination steps. The presentation delves into the selectivity of ionic chain polymerizations and the nature of propagating species. It also discusses the kinetics, chain transfer, and termination reactions involved in cationic polymerization. The lecture concludes with insights into living cationic polymerization and its applications in commercial products like polyisobutylene and butyl rubber.

Instructor

Harm-Anton Klok

Expertise Polymer design at nanoscaleBiologically-inspired polymers Mission Research at the Laboratory of Polymer (LP) focuses on the development of novel advanced polymeric materials with potential applications in optics, electronics or medicine. The philosophy is that precise control over nanoscale structure is an important prerequisite to tailor polymer properties. To this end, a “bottom-up” approach is followed, which starts with designing a new material at the molecular level, in order to be able to pr

Official source

Ontological neighbourhood

Chemistry

Organic chemistry: Polymer chemistry

Related concepts (32)

Polymerization

In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them. In chemical compounds, polymerization can occur via a variety of reaction mechanisms that vary in complexity due to the functional groups present in the reactants and their inherent steric effects.

Radical polymerization

In polymer chemistry, free-radical polymerization (FRP) is a method of polymerization by which a polymer forms by the successive addition of free-radical building blocks (repeat units). Free radicals can be formed by a number of different mechanisms, usually involving separate initiator molecules. Following its generation, the initiating free radical adds (nonradical) monomer units, thereby growing the polymer chain. Free-radical polymerization is a key synthesis route for obtaining a wide variety of different polymers and materials composites.

Living polymerization

In polymer chemistry, living polymerization is a form of chain growth polymerization where the ability of a growing polymer chain to terminate has been removed. This can be accomplished in a variety of ways. Chain termination and chain transfer reactions are absent and the rate of chain initiation is also much larger than the rate of chain propagation. The result is that the polymer chains grow at a more constant rate than seen in traditional chain polymerization and their lengths remain very similar (i.e.

Chain transfer

Chain transfer is a polymerization reaction by which the activity of a growing polymer chain is transferred to another molecule. P• + XR' → PX + R'• Chain transfer reactions reduce the average molecular weight of the final polymer. Chain transfer can be either introduced deliberately into a polymerization (by use of a chain transfer agent) or it may be an unavoidable side-reaction with various components of the polymerization.

Ring-opening polymerization

In polymer chemistry, ring-opening polymerization (ROP) is a form of chain-growth polymerization, in which the terminus of a polymer chain attacks cyclic monomers to form a longer polymer (see figure). The reactive center can be radical, anionic or cationic. Some cyclic monomers such as norbornene or cyclooctadiene can be polymerized to high molecular weight polymers by using metal catalysts. ROP is a versatile method for the synthesis of biopolymers. Ring-opening of cyclic monomers is often driven by the relief of bond-angle strain.

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