Predicting chain length distribution in step growth polymerization by monte carlo method wahyudi budi sediawan1, megawati2. Jan 30, 2012 an introduction to step growth polymerization. Predicting chain length distribution in step growth. Stepgrowth polymerization article about stepgrowth. 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. In this classification scheme, a stepgrowth polymerization is defined as one that involves a random reaction of two molecules that may be any combination of a monomer, oligomer, or a longerchain molecule.
In this dissertation, theoretical and experimental studies of stepgrowth polymerization of bapc are presented to gain better understandings in both solidstate polymerization ssp and melt copolymerization systems. Nanoparticles from stepgrowth coordination polymerization. Stepgrowth polymerization process modeling and product. Reaction engineering of step growth polymerization springerlink. 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. Effects of the polyethylene glycol hydrogel crosslinking. Plastic resins used in molding are formed by connecting many short units monomers into long, chain lengths polymers. A detailed discussion of several important step growth polymeriz ations follows in the next five chapters. Polymerization is an important process in so many industries. 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.
Usually, for chain growth polymerization, there is no byproduct formed. This assumption greatly simplifies the otherwise very complicated kinetics of a condensation polymerization. In this equation, p is the polymer while x represents degree of polymerization, means active center of chaingrowth polymerization, m is the monomer which will react with active center, l is a lowmolarmass byproduct obtained during chain propagation. 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. Growth involves monomer units reacting with each other or with oligomers of any size. Reaction engineering of step growth polymerization. In chaingrowth polymerization also called addition polymerization reaction occurs by. In the context of a stepgrowth polymerization via mukaiyama aldolization. Stepgrowth polymerization 1 polyester polyamide polycarbonate r 1 n h o r. Chaingrowth polymerizations require the presence of an initiating molecule that can be used to attach a monomer molecule at the beginning of the polymerization. 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. The two most important step growth polymerizations are condensation and addition 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. 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.
First, we examine how the degree of polymerization. Polyethylene falls under the category of chaingrowth polymerization polymerization reactions types of polymerization polymerization can proceed according to two different mechanisms, referred to as chaingrowth and stepgrowth polymerization. Many naturally and synthetic polymers are produced by stepgrowth polymerization including polyesters, polyethers, urethanes, epoxies. 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. Apr 21, 2017 college level organic chemistry 2 chapter 26 including closed captioned video.
Made by faculty at the university of colorado boulder department of chemical and biological engineering. In this equation, p is the polymer while x represents degree of polymerization, means active center of chain growth polymerization, m is the monomer which will react with active center, l is a lowmolarmass byproduct obtained during chain propagation. While the demands on materials continue to expand, stepgrowth polymerization reactions will remain relevant and useful to researchers across the research sectors. Stepgrowth polymerization an overview sciencedirect topics.
Longer chain lengths give higher molecular weight mw and lower melt flow rates. A polymerization mechanism which usually favors the formation of cyclic polymers is the zwitterionic polymerization, but an exception from. Nanoparticles from step growth coordination polymerization. Atom transfer radical polymerization atrp has proven to be a powerful technique to obtain polymers with narrow polydispersities and controlled molecular weight. Polymerization is the process by which monomer molecule undergoes chemical reaction to form polymer chains. College level organic chemistry 2 chapter 26 including closed captioned video. Small molecules such as water are eliminated by the chemical reaction in step growth polymerization. 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. In fact polyurethane polymerizes with addition polymerization because its polymerization produces no small molecules, but its reaction mechanism corresponds to a step growth polymerization. Quantitative analysis of stepgrowth polymers by size exclusion. Polymer synthesis a s discussed in chapter 1, a useful classification of all polymers is based upon the kinetics of the polymerization. Stepgrowth polymerization request pdf researchgate. Chain growth and step growth polymerization are described in.
Figure 41 molecular mass distributions in step growth polymerization. Flory assumed that all steps, that is, the formation of dimers, trimers and so forth, have equal rate constants. Heat released by the reaction is absorbed by the solvent, and so the reaction rate is reduced. 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. Difference between chain growth and step growth polymerization. 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. Here molecular weight of monomer and repeat unit is different, bi product my h 2 o, co 2, nh 3 etc. Step growth polymerization, types of monomers, kinetics and equilibrium considerations, closed vs. Bisphenol a polycarbonate bapc is a versatile engineering polymer that has a broad spectrum of applications. The distinct initiation, propagation, and termination steps of chaingrowth polymerization are meaningless in stepgrowth polymerization.
The technique is the most studied and utilized of the controlledliving radical polymerization techniques since a large number of monomers. N o o r h n n stepgrowth polymerization 4 nylon 6,6 aromatic polyamide. In chain growth polymerization also called addition polymerization reaction occurs by. Stepgrowth polymerization an overview sciencedirect. 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. 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. The growth of np chains was described by the kinetics and statistics of step growth 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.
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. Step growth polymerization, or condensation polymerization, is commonly employed to produce polyesters and nylons. Chaingrowth polymerization, by contrast, requires at least three distinctly different kinds of reactions to describe the mechanism. Comprehensive heterocyclic chemistry iii, 2008 related terms. Chain growth polymerization has been successfully performed for many decades through conventional free radical, anionic, or cationic polymerization. Step polymerisation polymerization materials science. Polyethylene falls under the category of chain growth polymerization polymerization reactions types of polymerization polymerization can proceed according to two different mechanisms, referred to as chain growth and step growth polymerization. The kinetics of the stepgrowth polymerization can be described with florys equal reactivity principle. Chaingrowth polymerization has been successfully performed for many decades through conventional free radical, anionic, or cationic polymerization. Chemical engineering 160260 polymer science and engineering. Mechanisms of polyemerization polymerization reactions types. The mechanism requires that at least two different monomers participate in the reaction. Chemical engineering, faculty of engineering, semarang state universitybldg. Stepgrowth polymerization refers to a type of polymerization mechanism in which bifunctional or multifunctional monomers react to form first dimers, then.
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. 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. Apr 30, 2015 characteristics of chain growth polymerisation growth by addition of monomer only at one end or both ends of chain some monomer remains even at long reaction times different steps operate at different stages of mechanism i. Read here for free the full introductory essay by andrew dove and michael meier. The nstep trajectory of the random walker is a chain of length nb folded. This assumption greatly simplifies the otherwise very complicated kinetics of a. In this classification scheme, a step growth polymerization is defined as one that involves a random reaction of two molecules that may be any combination of a monomer, oligomer, or a longerchain molecule. The polymerization of unsaturated monomers typically involves a chain growth polymerization.
What is the difference between stepgrowth polymerisation, chaingrowth polymerisation and copolymerisation. The distinct initiation, propagation, and termination steps of chain growth polymerization are meaningless in step growth polymerization. This mechanism of scattering is called rayleigh scattering. These polymerization techniques generate many important commodity polymers where their broad range of molecular weight distribution gives rise to important physical properties. 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. Initiation, propagation, termination, and chain transfer molar mass of backbone chain increases rapidly at early stage. 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. This is one of the earliest topics i was teaching in the polymer science and engineering course. During propagation, only monomers react to the active site at the end of the growing chain. The molecular weight mw of plla is a significant determinant of the quality of its products and can be tailored while synthesizing it through stepgrowth polymerization of lactic acid or chaingrowth polymerization of lactide dimer, both in bulk as well as in solution state 3. The reaction results in a polymer which is also soluble in the chosen solvent. It is known that chaingrowth polymerization can create a more heterogeneous network structure than stepgrowth polymerization. Now that we have learnt about polymers and their types, let us learn about polymerization. All molecules present monomer, oligomer, polymer can react with any other molecule.
The polymerization reaction occurs between the functional groups of molecules. If the monomers add end to end and liberate a byproduct is called step growth polymerization. Step growth polymerization an overview sciencedirect. Growth proceeds by a stepwise intermolecular reaction. Here we will look at condensation polymerization and step growth polymerisation. Feature article stepgrowth polymerization and click chemistry. Step growth polymerization and condensation polymerization step growth polymerization and condensation polymerization are two different concepts, not always identical. The reaction can be carried out in solution, in bulk melt, or in solid state. In this procedure, a monomer is dissolved in a nonreactive solvent that contains a catalyst. The first six chapters present the principles of step growth polymerization. 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. These 3 types of polymerization share 3 common steps. Many naturally occurring and some synthetic polymers are produced by step growth polymerization, e.
Made by faculty at the university of colorado boulder department of chemical and biological. Characteristics of chaingrowth polymerisation growth by addition of monomer only at one end or both ends of chain some monomer remains even at long reaction times different steps operate at different stages of mechanism i. Chemical engineering, faculty of engineering, gadjah mada university jl. Polymerization of resin is completed by one of two methods. Controlled radical polymerization guide sigmaaldrich.
Growth regulated by regulating nucleation of new barbed ends this is done by regulating the amount of active arp23. Stepgrowth polymerization journal of chemical education. Solution polymerization is a method of industrial polymerization. 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. The main difference between chain growth polymerization and step growth polymerization is that the chain growth polymerization involves the growth a polymer chain at its ends whereas. 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. Step growth polymerization process modeling and product design. Many naturally occurring and some synthetic polymers are produced by stepgrowth polymerization, e. Plastic resins used in molding are formed by connecting. The polyester dacron and the polyamide nylon 66, shown here, are two examples of synthetic condensation polymers, also known as step growth polymers. What is the difference between stepgrowth polymerisation. Converting monomer to long chain polymer is the final step in the polymer manufacturing sequence. Step growth polymerization process modeling and product design seavey, kevin, liu, y.
Stepgrowth polymerization of inorganic nanoparticles. Pdf simultaneous chaingrowth and stepgrowth polymerization. Ch 26 stepgrowth polymers condensation polymerization. Pdf since its discovery in 2001, copper catalyzed azidealkyne click chemistry. These are quite general, and can easily be applied in such diverse and emerging fields as polymerization applications in photolithography and microelec tronics. Differences between step growth polymerization and chain growth 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 extents of reaction are required to obtain high chain. New polymers synthesis by organocatalyzed stepgrowth. The reactivity of a functional group is independent of the size of the molecule to which it is attached.
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