Reaction engineering of step growth polymerization santosh. However, viscosity versus temperature profiles of both experimental studies and gelforming simulation studies indicate that the degree of pol. During propagation, only monomers react to the active site at the end of the growing chain. Reaction engineering of step growth polymerization. Polymerization reactor modeling in industry mueller. Buy this book isbn 97814618019 digitally watermarked, drmfree included format. Viscosity increases as conversion increases, making heat removal and processing more difficult. Introduction polymerization kinetics and modeling industrial step. Reaction engineering of step growth polymerization by santosh k. We note that p is the extent of polymerization reaction.
The value of n xn l for linear step growth polymerization was theoretically determined as in 33 n xn l 1. Course objectives after this course, students should clearly understand the concepts of polymer reaction engineering. An understanding of processes occurring in the polymerization reactor is therefore crucial to achieving efficient, consistent, safe and environmentally friendly production of polymeric materials. These are quite general, and can easily be applied in such diverse and emerging fields as polymerization applications in photolithography and microelec tronics. Growth polymerization polymer reaction engineering. Once a product passes laboratory tests, it is scaled up to a pilot plant and, after iteration, to a new or existing plant. Anshuman shrivastava, in introduction to plastics engineering, 2018. Not all step growth reactions are condensation reactions, however. In chain growth or chain polymerization, the only chainextension reaction step is the addition of a monomer to a growing chain with an active center such as a free radical, cation, or anion. The reaction of polyol and isocyanate monomers to form polyurethanes is commonly presented in reaction chemistry that implies a step growth mechanism for the polymerization. Fundamentals of polymer engineering, third edition 3rd edition ani. Dec 21, 2011 the literature in polymerization reaction engineering has bloomed sufficiently in the last several years to justify our attempt in putting together this book. Reaction engineering of step growth polymerization the. The first six chapters present the principles of step growth polymerization.
Used for free radical polymerization ps, pmma and some step growth. Third, the reaction responsible for the polymerization must. We pioneer the synthesis of welldefined high molar mass segmented copolymers, employing a unique combination of step growth and reversible additionfragmentation chain transfer raft polymerization. Reaction engineering of step growth polymerization dec 21. Step growth polymerization an overview sciencedirect. The major distinctions between these two methods, which, hopefully, will become apparent from the following discussion, result from thedifferences in kinetics of the polymerization reactions. Here the covalent bonding occurs by an s n 2 reaction between a nucleophile, usually an amine, and a terminal epoxide. Step growth polymerization is the formation of a polymer from bifunctional or multifunctional monomers.
Growth polymerization polymer reaction engineering wiley online library. Rather than offer a comprehensive treatment of the entire field, thereby duplicating earlier texts as well as some ongoing bookwriting efforts, we decided to narrow down our aim to step. By looking at the polymer growth reaction, chainwise and stepwise poly. Fusing lightinduced stepgrowth processes with raft. Therefore, properly managing heat transfer is very critical for controlling the polymerization reaction. Stepgrowth polymerization or condensation polymerization. Stepgrowth polymerization forms polymers in a manner that is. Choi, kyu yong department of chemical and biomolecular. Just by looking at the equation of reaction, we expect that every time a polymer molecule is made, a monomer molecule is used up. R t decreases at high conversion due to the trommsdorf effect, making the reaction hard to control.
Stepgrowth polymerization refers to a type of polymerization mechanism in which bifunctional or multifunctional monomers react to form first dimers, then trimers, longer oligomers and eventually long chain polymers. This is equivalent to number average molecular weight of. Chaingrowth polymerization or addition polymerization. Simplest polymerization technique high yield and highest purity easy polymer recovery direct processing casting possibility limitations difficulty in removing residual monomer heat dissipation esp. Polymer synthesis i am inclined to think that the development of polymerization. Reaction engineering of step growth polymerization springerlink. Fundamentals of polymer engineering, third edition 3rd. Difference between chain growth and step growth polymerization. Stepgrowth polymerization an overview sciencedirect topics. Examples of such functional groups are carboxylic acids, which react with alcohols to form esters and with amines to form amides here r and r.
During polymerization, smaller molecules, called monomers or building blocks, are chemically combined to create larger molecules or a macromolecule. In the scheme involving initiation, growth and termination, v. Once the growth of a chain is initiated by formation of an active center, chain propagation is usually rapid by addition of a sequence of monomers. Gupta and kumars 1987 book is specific to step growth polymerization. Stiile colorado state university, fort collins, co 80523 as illustrated in the articles on chain polymerization, a chain growth polymerization is one in which each polymer chain, after being started by a free radical initiator, a cationic catalyst or an anionic catalyst, grows rapidly, producing a high molecular weight polymer. Concepts in polymer engineering, principles of polymer reaction engineering, step growth and chain growth polymerization, copolymerization, polymerization processes, polymer stability and degradation. New polymers synthesis by organocatalyzed stepgrowth. Simultaneously, a byproduct is produced from the reaction sometimes water which is why this polymerization is sometimes termed condensation polymerization. In step growth or step polymerization, each step may involve the combination of two polymer molecules of any lengths to form a longer polymer molecule. Exploring the chemistry of synthesis, mechanisms of polymerization, reaction engineering of step growth and chain growth polymerization, polymer characterization, thermodynamics and structural, mechanical, thermal and transport behavior of polymers as melts, solutions and solids, fundamentals of polymer engineering, third edition covers essential concepts and breakthroughs in. Many naturally occurring and some synthetic polymers are produced by stepgrowth polymerization, e.
Lecture 5 examples of stepgrowth polymers elearning. Stepgrowth polymerization american chemical society. All molecules present monomer, oligomer, polymer can react with any other molecule. Stiile colorado state university, fort collins, co 80523 as illustrated in the articles on chain polymerization, a chain growth polymerization is one in which each polymer chain, after being started by a free radical initiator, a cationic catalyst or an anionic catalyst, grows rapidly, producing a high. Growth products, processes and modeling summary step.
Chemical engineering 160260 polymer science and engineering. Growth proceeds by a step wise intermolecular reaction. Condensation polymerization is now referred to as step growth or step reaction polymerization. Download full step growth polymerization process modeling and product design book or read online anytime anywhere, available in pdf, epub and kindle. Modelling and estimation of polycondensation processes. Step growth polymerization typically takes place between monomers containing functional groups that react in high yield to form new functionalities. Reaction engineering of step growth polymerization cep. Gautam jaiswar, in materials for biomedical engineering, 2019. Dynamic networks that drive the process of irreversible step.
Reaction engineering of step growth polymerization by. Radical chain polymerization comparison with ionic. Reaction engineering of step growth polymerization by santosh. Polymerization takes place between two monomer molecules, a monomer and polymer segment, or two polymer segments 76.
There are two main classes of polymerization reaction mechanisms. The step growth precursor polymer is obtained via the ambient temperature uvlightinduced dielsalder reaction of 6. Kyu yong choi has been a member of the department of chemical and biomolecular engineering since 1984, and was an affiliate of the institute for systems research isr from 1993 to 2004. Polymerization that is not sufficiently moderated and proceeds at a fast rate can be very hazardous. Molecular weight distribution mwd in equilibrium step condensation polymerizations. This phenomenon is known as hazardous polymerization and can cause fires and explosions. Controlled stepgrowth polymerization ccs chemistry. Polymerization reactions can be very complex chemical reactions with many different side reactions. Polymerization processes hamielec major reference works.
Because of this loss of compounds during the polymerization process, reactions of this type are often called condensation reactions. Monomer does not react with monomer and species such as dimer and trimer do not react with each other. The literature in polymerization reaction engineering has bloomed sufficiently in the last several years to justify our attempt in putting together this book. Chain growth polymers chain polymer growth takes place by monomer reacting only with the reactive centers. A major objective of polymerization reaction engineering is to. Kinetics of step growth polymerization chapter 2 mit. Rather than offer a comprehensive treatment of the entire field, thereby duplicating earlier texts as well as some ongoing bookwriting efforts, we decided to narrow down our aim to step growth polymerization systems. Chain growth polymerization mechanism in polyurethaneforming. Pdf step growth polymerization process modeling and product.
Polymers are an example of productsbyprocess, where the final product properties are mostly determined during manufacture, in the reactor. Polymerization processes are categorized into two broad classes, according to their reaction mechanisms. Used for free radical polymerization ps, pmma and some step growth condensation polymerizations. A detailed discussion of several important step growth polymeriz ations follows in the next five chapters. Chappelear and simon polymerization reaction engineering 3 this approach to succeed. In step growth polymerization, oligomers are formed at the beginning and are later combined together, forming the polymer chain. The polymerization reaction occurs between the functional groups of molecules. Small molecules such as water are eliminated by the chemical reaction in stepgrowth polymerization. Stepgrowth polymerization forms polymers in a manner that. The polymerization ceases when the active center is destroyed by termination reactions. Exploring the chemistry of synthesis, mechanisms of polymerization, reaction engineering of stepgrowth and chaingrowth polymerization, polymer. Kinetics of different methods of polymerization institut fur chemie. The functional groups on two monomers react to form a dimer, the dimer reacts with another monomer to form a trimer, and these reactions lead to many monomeric units linked to form an intermediate molecular weight material, which is known as an oligomer, and eventually a polymer. Growth involves monomer units reacting with each other or with oligomers of any size.
The evolution of the degree distribution is governed by the reaction kinetics of the stepgrowth polymerization. Step growth and chain growth are the main classes of polymerization reaction mechanisms. In chain growth polymerization, propagation is followed by the direct reaction of a species. Gupta, modeling of intramolecular reactions in the step growth polymerization of multifunctional monomers, polymer 27, 583591 1986. As the name suggests, step growth polymerization proceeds in a step wise fashion. Chain growth polymerization mechanism in polyurethane. He leads the polymer reaction engineering laboratory, which focuses on polymerization kinetics, polymerization reactorprocess modeling, control, and optimization. The primary role of reaction engineering shown by the highlighted boxes is to aid this scaleup. Step growth polymerization, types of monomers, kinetics and. Stepgrowth polymerization of inorganic nanoparticles.
In step growth polymerization, the molecules build up slowly. Reaction engineering of step growth polymerization santosh k. Polymer reaction engineering, an integrated approach wileyvch. Synthetic polymers are synthesized from monomers by a multitude of reaction mechanisms, including addition and step growth reactions, and polymerization processes e. Polymerization processes typically have the characters of fast reaction rate, high viscosity of reaction mixture, and being highly exothermic. Stepgrowth polymerization, or condensation polymerization, is commonly employed to produce polyesters and nylons. These polymers are then processed to make various kinds of plastic products. The reactivity of a functional group is independent of the size of the molecule to which it is attached. The most common type of reaction in forming resin via step growth polymerization involves the formation of a new bond covalent bond between the two functional groups. High molecular weight is only achieved at very high degrees of conversion. Rather than offer a comprehensive treatment of the entire field, thereby duplicating earlier texts as well as some ongoing bookwriting. First, we examine how the degree of polymerization and its distribution vary with the progress of the polymerization. Kinetics of stepgrowth polymerization chemistry libretexts.
Step growth polymerizations can be divided into two lasses. One way of classification of polymerization reactions is to look at the polymer growth reaction, which is essential for polymer formation. Lecture notes on structure and properties of engineering polymers. Growth proceeds by a step wise intermolecular reaction growth involves monomer units reacting with each other or with oligomers of any size the reactivity of a functional group is independent of the size of the molecule to which it is attached the reactivity of a functional group is independent of. Chemistry of industrial polymers stepgrowth polymerization. The average molar mass increases slowly and long chains are formed only late in the reaction.
The literature in polymerization reaction engineering has bloomed sufficiently in. In the following example, the same bisphenol a intermediate used as a monomer for lexan serves as a. Also, unlike step growth polymerization, chain growth polymerization requires the presence of an active center. Aug 25, 2020 step growth polymerization is also used for preparing a class of adhesives and amorphous solids called epoxy resins. Step growth polymerization process modeling and product design. Stepgrowth polymerization an overview sciencedirect.
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