Stepgrowth polymerization of inorganic nanoparticles science. Lower yield per reactor volume, reduced reaction rate and average chain length. First of all, it has been shown that this reaction is catalyzed by chain end groups bsi which change in concentration with reaction conversion. Viscosity increases as conversion increases, making heat removal and processing more difficult. Small molecules such as water are eliminated by the chemical reaction in step growth polymerization. Stepgrowth polymerization process modeling and product design kevin seavey, y.
Polymer reaction engineering provides the link between the fundamentals of polymerization kinetics and polymer microstructure achieved in the reactor. Stepgrowth polymerization of inorganic nanoparticles. Stepgrowth polymerization forms polymers in a manner that is. During propagation, only monomers react to the active site at the end of the growing chain. Ch 26 stepgrowth polymers condensation polymerization. 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. We report on the marked similarity between the selfassembly of metal nanoparticles and reaction controlled step growth polymerization.
Understand quantitative model stepgrowth polymerization plans and how to predict properties of the product polymer with the essential information in stepgrowth polymerization process modeling and product design. The mw and the mw distribution, referred to as polydispersity, are two fundamental factors that dictate the physical nature of polymeric materials. Modeling and control of polymer properties 149 korean j. The polymerization reaction occurs between the functional groups of molecules. Each stage in stepgrowth polymerization involves a reaction between. These are quite general, and can easily be applied in such diverse and emerging fields as polymerization applications in photolithography and microelec tronics. Reaction engineering of step growth polymerization. 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 or ion. B reaction is that used to make cocacola bottles i.
The monomer molecules may be all alike, or they may represent two, three, or more different compounds. Stepgrowth polymerization request pdf researchgate. An analysis of caprolactam polymerization reaction engineering viewpoint, however, several features are important. Figure 1 features a few important examples related to polyesters, polyamides, and polyurethanes. Controlled stepgrowth polymerization ccs chemistry. We shall sometimes use the terms step growth and condensation polymers as synonyms, although step growth polymerization. Request pdf stepgrowth polymerization stepgrowth polymerization is a very. The past decade has witnessed great progress in nanoparticle selfassembly, yet the quantitative prediction of the architecture of nanoparticle ensembles and of the kinetics of their formation remains a challenge. Equilibrium step condensation polymerizations, interchange reactions. Synthesis of macromolecules by step growth polymerization 4. Stepgrowth polymerization forms polymers in a manner that is quite different from chain. Stepgrowth polymerization an overview sciencedirect topics. Stepgrowth polymerization, or condensation polymerization, is commonly employed to produce polyesters and nylons.
Stepgrowth polymerization article about stepgrowth. In stepgrowth polymerization, the molecular weight of the polymer chain builds up slowly and there is only one reaction mechanism for the formation of polymer. Small molecules such as water are eliminated by the chemical reaction in stepgrowth polymerization. The science and engineering of materials, pws publishing company, 1994. This imparts an autocatalytic character to the reaction. Classification of polymerization reaction addition and. College level organic chemistry 2 chapter 26 including closed captioned video. Stepgrowth polymerization forms polymers in a manner that is quite different from chaingrowth polymerization. Step reactions require bifunctional or polyfunc tional monomers, while chain reactions require the presence of an initiator. Control of molecularweight distribution in stepgrowth. Synthesis of macromolecules by step growth polymerization 4 4. It is the third of these criteria that offers the most powerful insight into the nature of the polymerization process for this important class of materials. Step growth polymerization is also used for preparing a class of adhesives and amorphous solids called epoxy resins.
Understand quantitative model step growth polymerization plans and how to predict properties of the product polymer with the essential information in step growth polymerization process modeling and product design. Once the propagation reaction within a given polymer chain is stopped either by a termination or chaintransfer step, usually no further chain growth occurs. The literature in polymerization reaction engineering has bloomed sufficiently in the. The literature in polymerization reaction engineering has bloomed sufficiently in. The present paper aimed at presenting some important stateofart problems on polymerization reaction engineering, and discussing, through some selected examples, on future directions and. Chemical engineering 160260 polymer science and engineering. In this context, the present manuscript investigates the stepgrowth polymerization of polyethylene 2,5furandicarboxylate, pef, a furanic polyester with structural similarity to polyethylene terephthalate, pet, using ethylene glycol eg, and 2,5furandicarboxylic acid fdca as monomers.
Step polymerisation polymerization materials science. The present paper aimed at presenting some important state of art problems on polymerization reaction engineering, and discussing, through some selected examples, on future directions and. In a stepgrowth polymerization, the molecular weight of the polymer chain builds. Reaction engineering of step growth polymerization santosh.
Step growth polymerization an overview sciencedirect topics. Many polymers with real world applications are formed as a result of stepgrowth polymerisation. The concepts here are explained in brief, for further details and clarification on the topic of polymerization reaction download byjus the. The distinct initiation, propagation, and termination steps of chaingrowth polymerization are meaningless in stepgrowth polymerization. The mechanism of the polymerization stepwise or chain reaction. In this lesson, learn about the process of polymerization. Sep 18, 2019 step growth polymerization is also used for preparing a class of adhesives and amorphous solids called epoxy resins. Figure 41 molecular mass distributions in step growth polymerization. Compared to chaingrowth polymerization, where the production of the growing chaingrowth is based on the reaction between polymer with active center and monomer, stepgrowth polymerization doesnt have initiator or termination. We report on the marked similarity between the selfassembly of metal nanoparticles and reactioncontrolled stepgrowth polymerization. Polymerization processes are categorized into two broad classes, according to their reaction mechanisms. Polymerization reactions are divided into two groups known as step reactions also called condensation reactions and chain reactions also known as addition reactions.
The discussion in chapters 2 and 3 has been limited to the polymerization of bifunctional monomers, which give linear polymer chains. Growth polymerization polymer reaction engineering wiley online library. Jan 01, 2007 an understanding of processes occurring in the polymerization reactor is therefore crucial to achieving efficient, consistent, safe and environmentally friendly production of polymeric materials. In the following example, the same bisphenol a intermediate used as a monomer for lexan serves as a. In a stepgrowth polymerization, the molecular weight of the polymer chain builds up slowly and there is only one re. Welldefined aromatic polyamides, polyesters, and polyethers have been synthesized via substituent effectassisted chaingrowth condensation polymerization, in which the polymer propagating ends are more reactive than the monomers due to resonance or inductive effects between the functional groups of. Polymerization, any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer. A detailed discussion of several important step growth polymeriz ations follows in the next five chapters.
The growth of np chains was described by the kinetics and statistics of stepgrowth polymerization 2426, which, for a particular time, allowed the prediction of the aggregation number and the size distribution of np ensembles, similar to the degree of polymerization and polydispersity index pdi of polymers, respectively. Third, the reaction responsible for the polymerization must. Here the covalent bonding occurs by an s n 2 reaction between a nucleophile, usually an amine, and a terminal epoxide. Stepgrowth polymerscondensation polymers chemistry. The other process, called step growth polymerization, involves the buildup of molecular weight not in a chainlike fashion but in a stepwise fashion, by the random combination of monomer molecules containing reactive functional groups. The monomer in stepgrowth polymerization will be consumed very quickly to dimer, trimer or oligomer. Step growth polymerization and condensation polymerization are two different concepts, not always identical. Interfacial polymerizations rely on reactions of diacid chlorides and active. The concepts here are explained in brief, for further details and clarification on the topic of polymerization reaction download byjus the learning app.
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. Stepgrowth polymerization is also used for preparing a class of adhesives and amorphous solids called epoxy resins. Apr 21, 2017 college level organic chemistry 2 chapter 26 including closed captioned video. In a stepreaction polymerization reaction, sometimes called condensation polymerization, the polymer chains grow by reactions that occur between two molecular species. Step growth polymerization does not require an initiator and occurs between monomers that carry reactive functional groups. Differences between stepgrowth polymerization and chaingrowth polymerization step growth chain growth growth throughout matrix rapid loss of monomer early in the reaction similar steps repeated throughout reaction process average molecular weight increases slowly at low conversion and high.
The other process, called stepgrowth polymerization, involves the buildup of molecular weight not in a chainlike fashion but in a stepwise fashion, by the random combination of monomer molecules containing reactive functional groups. Building on concepts presented in an earlier cep article on plastics 1, this article explores some of the most important of those principles related to selecting, sizing, and troubleshooting polymerization reactors. Differences between step growth polymerization and chain growth polymerization. Introduction polymerization kinetics and modeling industrial step. R t decreases at high conversion due to the trommsdorf effect, making the reaction hard to control. Stepgrowth polymerization does not require an initiator and occurs between monomers that carry reactive functional groups.
The two most important stepgrowth polymerizations are condensation and addition polymerization. Explore the two major types, common polymers, and some of the chemistry involved with this biologically and commercially important. The quantitative match of the prism assembly statistics with reactionlimited stepgrowth polymerization has implications potentially generalizable to other. Imaging the polymerization of multivalent nanoparticles in. All molecules present monomer, oligomer, polymer can react with any other molecule. In a stepgrowth polymerization, the molecular weight of the polymer chain builds up slowly and there is only one reaction mechanism for the formation of polymer. Stepgrowth polymerization process modeling and product. Professor of chemical engineering, institute for polymer materials polymat, the university of the basque country, spain search for more papers by this author first published. To be successful in this field, a chemical engineer needs to understand a few principles beyond the basics of reaction engineering. The first six chapters present the principles of step growth polymerization.
An understanding of processes occurring in the polymerization reactor is therefore crucial to achieving efficient, consistent, safe and environmentally friendly production of polymeric materials. The number distribution a is shown for three different extents of reaction, the mass distribution b shows a single narrow peak which progressively broadens and shifts to high molecular mass as. Step growth polymerization, types of monomers, kinetics and equilibrium considerations, closed vs. The literature in polymerization reaction engineering has bloomed sufficiently in the last several years to justify our attempt in putting together this book. Stepgrowth polymerization journal of chemical education. Simulation studies of stepgrowth polymerization, e. Stepgrowth polymerization is the method most commonly employed. A continuation order plan is available for this series. Used for free radical polymerization ps, pmma and some step growth condensation polymerizations. Stepgrowth polymerization forms polymers in a manner that. In a step reaction polymerization reaction, sometimes called condensation polymerization, the polymer chains grow by reactions that occur between two molecular species. Step growth polymerization, or condensation polymerization, is commonly employed to produce polyesters and nylons. The mechanism requires that at least two different monomers participate in the reaction. In step growth polymerization, the molecular weight of the polymer chain builds up slowly and there is only one reaction mechanism for the formation of polymer.
So far we have seen that there are two types of the polymerization reaction, how the polymerization of monomers take place and the addition and condensation mechanism. Reaction engineering of step growth polymerization springerlink. Many polymers with real world applications are formed as a result of step growth polymerisation. An example is the polymerization reaction involving terephthalic acid and ethylene glycol, both of which are bifunctional. Polymerization proceeds by the reaction of two different functional groups. Step growth polymerization process modeling and product design kevin seavey, y. The distinct initiation, propagation, and termination steps of chain growth polymerization are meaningless in step growth polymerization. There are several industrially important systems, e. Growth polymerization polymer reaction engineering. Rather than offer a comprehensive treatment of the entire field, thereby duplicating earlier texts as well as some ongoing bookwriting. Dynamic networks that drive the process of irreversible step.
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