Examples of such functional groups are carboxylic acids, which react with alcohols to form esters and with amines to form amides. Stepgrowth polymerization refers to a type of polymerization mechanism in which bifunctional or multifunctional monomers react to form first dimers, then. We use cookies to offer you a better experience, personalize content, tailor advertising, provide social media features, and better understand the use of our services. Stepgrowth polymerization is a very important method for the preparation of some of the most important engineering and specialty polymers. Polymer science submitted by 1st year 2nd semester group. Step growth polymerization and condensation polymerization step growth polymerization and condensation polymerization are two different concepts, not always identical. 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. Step growth 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. Polymerization is usually highly favourable in thermodynamic terms, mainly on energetic grounds because ordering molecules into linked chains is a process where the entropy is decreased. Growth polymerization driven by electrochemical stimuli from an electrode jian zhang state key laboratory of polymer physics and chemistry, changchun institute of applied chemistry ciac, changchun, 022 china. Propagation it is the middle step in chain polymerization where successive monomers are attached to the growing chain.
Stepgrowth polymerization typically takes place between monomers containing functional groups that react in high yield to form new functionalities. Control of reactions and network structures of epoxy thermosets. Made by faculty at the university of colorado boulder department of chemical and biological. This can induce chain branching through the terminal double bond propagation reaction. Here the covalent bonding occurs by an s n 2 reaction between a nucleophile, usually an amine, and a terminal epoxide. Chaingrowth and stepgrowth polymerization are described in. In this context, the present manuscript investigates the step growth 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. The first six chapters present the principles of step growth polymerization. Since, each step produces a distinct functionalised species and is independent of each other, this process is also called as step growth polymerisation. Molecular weight control, molecular weight determination in. The synthetic processes of producing polymers from their monomers can be divided into stepgrowth and chaingrowth polymerization. Nov 10, 2015 simultaneous step growth and chain growth cationic polymerization of styrenic monomers bearing carbazolyl groups. Chemistry of industrial polymers chemistry of industrial polymers stepgrowth polymerization.
Stepgrowth polymerization is the method most commonly employed, although hydrogenbonddriven polypseudorotaxane formation has also been reported from preformed polyurethane backbones in combination with 30crown10 or 42crown14 rings. Davis the school of chemistry,the university of reading, uk published by oxford university press is a department of the university of oxford. 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. Book principles of polymerization odian solution manual.
Control of molecularweight distribution in stepgrowth. This assumption greatly simplifies the otherwise very complicated kinetics of a condensation polymerization. Comprehensive heterocyclic chemistry iii, 2008 related terms. Chain growth polymerization is basically a threestage process, involving initiation of active molecules, their propagation and termination of the active chain ends. Stepgrowth polymerization journal of chemical education.
Each stage in stepgrowth polymerization involves a reaction between dissimilar chemical groups which are part of the monomer molecules. The kinetics of the stepgrowth polymerization can be described with florys equal reactivity principle. Dhooge, christopher barnerkowollik,2,3 european polymer federation, lyon, france, 0207072017. Interfacial polymerization is a type of step growth polymerization in which polymerization occurs at the interface between two immiscible phases generally two liquids, resulting in a polymer that is constrained to the interface.
There are several variations of interfacial polymerization, which result in several types of polymer topologies, such as ultrathin films, nanocapsules, and. Ep4 step growth polymerization, carothers equation, molecular weight ucsd nano 4 darren lipomi step growth. Ep4 step growth polymerization, carothers equation, molecular weight ucsd nano 4 darren lipomi step growth polymerization vs chain growth, to be covered in more detail later in the course, extent of reaction, numberaverage. 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. Jan 30, 2012 an introduction to step growth polymerization. A stepgrowth polymerization is a stepwise reaction between bifunctional or multifunctional monomers in which a highmolecularweight polymer is formed after a large number of steps. Stepgrowth polymers have been known since the discovery of synthetic polymers as useful polymeric materials within wide application areas. 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 forms polymers in a manner that is quite different from chaingrowth polymerization. Cannot be used for polymers whose glass transition temperature is less than the polymerization temperature, or else aggregation will occur. What are the differences between step and chain polymerization reaction.
Stepgrowth polymerization american chemical society. Chemistry of industrial polymers stepgrowth polymerization. Polymerization yields finely divided, stable latexes and dispersions to be used directly in coatings, paints, and adhesives. Step growth polymerization of colloidal monomers into chains. Small molecules such as water are eliminated by the chemical reaction in stepgrowth polymerization.
Book of polymer chemistry a practical approach by fred j. 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. Stepgrowth polymerization is also used for preparing a class of adhesives and amorphous solids called epoxy resins. This file contains additional information such as exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. These are quite general, and can easily be applied in such diverse and emerging fields as polymerization applications in photolithography and microelec tronics. In this type of polymerisation, the molecules of the same monomer or diferent monomers add together on a large scale to form a polymer.
Why are condensation polymers called as step growth. In fact polyurethane polymerizes with addition polymerization because its polymerization produces no small molecules, but its reaction mechanism corresponds to a step growth polymerization. B through individual aa and bb coupling reactions driven by electrochemically positive and negative bias on a self. Converting monomer to long chain polymer is the final step in the polymer manufacturing sequence. Stepgrowth polymerization forms polymers in a manner that is. 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. Dec 04, 2014 while the demands on materials continue to expand, stepgrowth polymerization reactions will remain relevant and useful to researchers across the research sectors. Many naturally and synthetic polymers are produced by stepgrowth polymerization including polyesters, polyethers, urethanes, epoxies. Stepgrowth polymerization an overview sciencedirect. The polyketals are synthesized via stepgrowth polymerization, we therefore speculate that their low molecular weight is due to an imbalance of the reactants during the polymerization process.
Stepgrowth polymerization forms polymers in a manner that. The polymerization reaction occurs between the functional groups of molecules. If you want to learn how to simulate stepgrowth polymerization processes using commercial software and seek an indepth, quantitative understanding of how to develop, use, and. If you want to learn how to simulate step growth polymerization processes using commercial software and seek an indepth. The synthesis of polyurethanes is an example of a stepgrowth polymerization that is not an actual condensation since no small molecules are eliminated during. The mechanism requires that at least two different monomers participate.
This assumption greatly simplifies the otherwise very complicated kinetics of a. In irreversible stepgrowth polymerization, the molecularweight distribution mwd of the polymers produced can be controlled via the reaction path. Sometimes, the polymerization involves the release of small molecule byproduct, so it is also called condensation polymerization. All structured data from the file and property namespaces is available under the creative commons cc0 license. To the second type belong monomers that have both functional groups needed for condensation on the same molecule. A number of polymers obtained in step growth polymerization reactions can be accounted to socalled functionally terminated thermoplastics, which combine toughness of thermoplastics and resistance. The step polymerization builds up the molecular weight of polymer by stepwise function. Imaging the polymerization of multivalent nanoparticles in. Pdf simultaneous chaingrowth and stepgrowth polymerization. Pdf reinvestigation of numerous ringopening polymerizations by means of malditof mass spectrometry has evidenced that cyclic polymers were formed. Stepgrowth polymerization an overview sciencedirect topics.
Files are available under licenses specified on their description page. A large number of important and useful polymeric materials are not formed by chaingrowth processes involving reactive species such as radicals but proceed instead by conventional functional group transformations of polyfunctional reactants. Step growth polymerization process modeling and product design seavey, kevin, liu, y. Step polymerization condensation involves a series of reactions in which any two species monomers, dimers, trimers, etc. Numerous and frequentlyupdated resource results are available from this search. Step growth polymerization is the method most commonly employed, although hydrogenbonddriven polypseudorotaxane formation has also been reported from preformed polyurethane backbones in combination with 30crown10 or 42crown14 rings. Due to the nature of the polymerization mechanism, the reaction has to proceed for a long time to achieve high molecular weight polymers. One variety of stepgrowth polymerization is called condensation polymerization and the product a condensation polymer because the chemical reaction by which the monomer molecules bond is often a condensation reaction that produces a small molecule byproduct. New polymers synthesis by organocatalyzed stepgrowth. In this study, we explore a new phenolic ligand system derived from nphenyl salicylimine 3, see figure 1 and its potential to control the propagation step of the roamp by reversible chelation to the molybdenum. Reliable information about the coronavirus covid19 is available from the world health organization current situation, international travel. Open systems kinetics of step growth polymerization chapter 2.
As illustrated in the articles on chain polymerization. In chaingrowth 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. Stiile colorado state university, fort collins, co 80523 as illustrated in the articles on chain polymerization, a chaingrowth 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. In a step growth polymerization, the molecular weight of the polymer chain builds up. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. To quantify the resulting growth process, we relate the linear prism chains to polymer chains grown out of molecular monomers with. Flory assumed that all steps, that is, the formation of dimers, trimers and so forth, have equal rate constants.
For example, aminocaproic acid has an amine group at one end and a carboxyl group at the other. All structured data from the file and property namespaces is available under the. Stepgrowth polymerization of inorganic nanoparticles. Jan 01, 2007 organized according to the type of polymerization, each chapter starts with a description of the main polymers produced by the particular method, their key microstructural features and their applications polymerization kinetics and its effect on reactor configuration, mass and energy balances and scaleup are covered in detail. A detailed discussion of several important step growth polymeriz ations follows in the next five chapters. Stepgrowth polymerization is a polymerization process that involves a chemical reaction between multifunctional monomer molecules. Stepgrowth polymerization forms polymers in a manner that is quite different from chain. The monomer in stepgrowth polymerization will be consumed very quickly to dimer, trimer or oligomer. In a stepgrowth polymerization, the molecular weight of the polymer chain builds up slowly and there is only one re action mechanism for the.
Step growth polymerization p olymerization mechanism in which bifunctional or multifunctional monomers react to form first dimers, then trimers, longer oligomers and eventually long chain polymers. One of the two monomers was immobilized as organic ligands of the metalorganic framework mof and polymerized with the mobile guest monomer, resulting in the formation of linear polymers. First, we examine how the degree of polymerization. Stepgrowth polymerization of colloidal monomers into chains.
As you can see from the equation given in the discussion on forming condensation polymers, dacron is formed from two monomers, one of which possesses. Addition polymerization the key feature of addition polymerization is that monomers add to one another in such a way that the polymeric product contains all the atoms of the starting monomers. 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. Reaction engineering of step growth polymerization springerlink. Principles of polymer synthesis types of polymerization for accessing 7activestudio videos on mobile download. Stepgrowth polymerization process modeling and product. Step growth polymerization, types of monomers, kinetics and equilibrium considerations, closed vs. Following a comparison of chain growth and step growth polymerization, focuses on the latter process by describing requirements for high molecular weight, step growth polymerization kinetics, synthesis and molecular weight distribution of some linear step growth polymers, and threedimensional network step growth polymers. Bidentate phenoxides as ideal activating ligands for. 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. Question 32 in step growth polymerization, chain length grows in a stepwise fashion. 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.
Stepgrowth polymerization article about stepgrowth. Objectives polymers national council of educational. It is used for most step growth polymers and many types of chain growth polymers. Stepgrowth polymerization request pdf researchgate. Step growth polymerization refers to a type of polymerization mechanism in which bifunctional or multifunctional monomers react to form first dimers, then trimers. In this section we discuss another important class of polymerization kknow as step. New polymers synthesis by organocatalyzed stepgrowth polymerization of aldehydic monomers. In the following example, the same bisphenol a intermediate used as a monomer for lexan serves as a. The two most important step growth polymerizations are condensation and addition polymerization. Most step polymerization involves a classical condensation reaction such as esterification, ester interchange or amidization. Step growth polymerization process modeling and product design.
The mechanism requires that at least two different monomers participate in the reaction. Transformation of stepgrowth polymerization into living. In the propagation stage, the process of electron transfer and consequent motion of the active. Bulk polymerization is carried out in the absence of any solvent or dispersant and is thus the simplest in terms of formulation. Step polymerisation polymerization materials science. Interfacial polymerization is a type of stepgrowth polymerization in which polymerization occurs at the interface between two immiscible phases generally two liquids, resulting in a polymer that is constrained to the interface.
The distinct initiation, propagation, and termination steps of chaingrowth polymerization are meaningless in stepgrowth polymerization. Stepgrowth polymerization, or condensation polymerization, is commonly employed to produce polyesters and nylons. Read here for free the full introductory essay by andrew dove and michael meier. To quantify the resulting growth process, we relate the linear prism chains to polymer chains grown out of. Oclcs webjunction has pulled together information and resources to assist library staff as they consider how to handle coronavirus. Chemical engineering 160260 polymer science and engineering. The formation of terylene or dacron by the interaction of ethylene glycol and terephthalic acid is an example of this type of polymerisation. 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. Following a comparison of chaingrowth and stepgrowth polymerization, focuses on the latter process by describing requirements for high molecular weight, stepgrowth polymerization kinetics, synthesis and molecular weight distribution of some linear stepgrowth polymers, and threedimensional network stepgrowth polymers. Synthetic methods in stepgrowth polymers provides a concise source of information on synthetic techniques, purification, and characterization methods for stepgrowth polymers and also addresses future synthetic trends. The initiation, propagation, and termination steps are distinctly different. Growth polymerization process modeling and product.