Lecture 45 polymerization techniques there are four types of polymerization techniques. Solution polymerization occur in existence of inert solvent and suitable catalyst, on the contrary of bulk polymerization which doesnt need any additives just monomer and a suitable initiator. A polymer is a macromolecule which consists of small molecular units that are repeated over and over again to form a long chain. Bulk polymerization is carried out in the absence of any solvent or dispersant and is thus the simplest in terms of formulation. It is similar to bulk polymerization where the reaction mixture is suspended as droplets in an inert medium. Bulk polymerization or mass polymerization is carried out by adding a soluble initiator to a pure monomer in liquid state.
Anna university engineering chemistry1 cy6151 notes unit1 polymer chemistry polymerization techniques bulk polymerization. These reactive sites can initiate the emulsion polymerization of the monomers. There are advantages to it such as higher purity, lowered cost and lower environmental impact. The ligninpcl copolymers were synthesized via rop of cl used in bulk process fig. In the first approach, a mixture of graphite oxide go and methylmethacrylate monomers mma were polymerized using a bulk polymerization method with a free radical initiator. These advanced polymerization techniques offer unprecedented opportunities in the tailored synthesis of an gigantic family of new polymers of various controlled macromolecular chain parameters, including molecular weight and distribution, chain architecture, comonomer composition and distribution, stereoregularity, etc. Four polymerization techniques bulk,solution,suspension and. This pdf gives a basic idea on general polymerization techniques. The real challenge concerns the dissipation of the heat produced by polymerization. A bulk addition polymerization is a homogeneous system with an organic initiator. The solid state reactions are usually slow, they are not considered practical for this reason. Bulk polymerization or mass polymerization is carried out by adding a soluble radical initiator to pure monomer in liquid state.
Bulk polymerization or mass polymerization is carried out by adding a soluble initiator to pure monomer in liquid state. Four polymerization techniques bulk,solution,suspension. In this work, a comparison of different techniques for the determination of conversion during suspension polymerization reactions. In solution polymerization, or for polymerizations carried out in the presence of chain transfer agents, the duration of the lowconversion regime is extended. Bulk polymerization solution polymerization suspension polymerization emulsion polymerization. The reaction is initiated by heating or exposure to radiation. The key difference between addition polymerization and condensation polymerization is that for addition polymerization, monomer should be an unsaturated molecule whereas for condensation polymerization, monomers are saturated molecules polymers are large molecules that have the same structural unit repeating over and over. Process for manufacturing macromolecular compounds process in solution. Lecture 4 polymerization techniques bulk polymerization. Find materials for this course in the pages linked along the left. Forsometime polymer chemists have realized that to approach natures degree ofsophistication, new synthetic techniques wouldbe needed. Other articles where bulk polymerization is discussed. To outline polymerization techniques and describe approaches to.
One such method is the group transfer polymerization gtp. Under emulsion polymerization conditions, free radicals are produced to initiate the polymer ization. Bulk polymerization is a radically initiated process that uses the monomer as the primary reactant medium. The discussion focuses on key areas where information for. Bulk and solution polymerization are two very important methods for manufacturing polymers. New polymerization techniques and synthetic methodologies. Bulk, solution, and atom transfer radical polymerization atrp techniques at different temperatures were applied. 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. At some point, the polymerization is terminated and the material is passed to another vessel for polymer isolation, unreacted monomer recovery, etc. Bulk polymerization is much more suited for stepgrowth polymers because these polymers have a much lower heat of polymerization and reactivity. Polymerization methods generally used for the preparation of mps include bulk, emulsion, suspension, and interfacial polymerization. Such a method is environmentally benign and facile to recover the polymer by. Techniques of polymerization in engineering chemistry.
Bulk polymerization, which may also be referred to as mass polymerization, involves a monomer and an initiator as the main components, without a solvent. Radical polymerization bulk polymerization of s and mma, 1 is typically 20%, 2 is 2085%, and 3 is 85%. In the case of the bulk polymerization technique, one or more monomers are heated to induce polymerization in the presence of a catalyst. Solvent reduces viscosity, making processing easier.
Acrylic plastic sheets are formed by a process known as bulk polymerization. These notes are preliminary and may contain errors. Following its generation, the initiating free radical adds nonradical monomer units, thereby growing the polymer chain. Some disadvantages related to the mechanism of free radical polymerization is the poor control of the molecular. The reaction is initiated by heating or exposing to radiation. Four polymerization techniques bulk,solution,suspension and emulsion free download as pdf file.
Bulk and solution radicalinitiated polymerization techniqu es. The simplest technique it gives the highestpurity polymer. Freeradical polymerization frp is a method of polymerization by which a polymer forms by the successive addition of freeradical building blocks. Polymerization shrinkage stress of composite resins and. Polymethylmethacrylategraphene pmmargo nanocomposites were prepared via in situ bulk polymerization using two different preparation techniques. Batch cell and continuous bulk polymerization to produce transparent pmma sheets. Batch cell and continuous bulk polymerization to produce. Solvent acts as a diluent and aids in removal of heat of polymerization. Bulk and solution radicalinitiated polymerization techniques. Polymerisation techniques polymerisation techniques used in the.
Emulsion polymerization is one of the most widely used polymerization techniques in industry, and emulsion polymers are utilized in various fields, including coatings, paints, inks, adhesives, and rubbers. If the polymer is insoluble in monomer, then initiation, propagation, and termination might happen in the monomer phase. Pdf bulk and solution polymerization are two very important methods for manufacturing polymers. 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. The polymerization curves showed autoacceleration mechanism and the limiting conversion was 100%. Bulk polymerization the method is used for the polymerization of liquid state. Clinical techniques that could reduce shrinkage stress and new. Bulk polymerization produces a monolithic rigid polymer matrix, needing to be. Synthesis and characterization of the in situ bulk. Introduction simplest of the techniques requiring only monomer and monomersoluble initiator, and perhaps a chain transfer agent for. Conventional chaingrowth polymerizations, for example, free radical synthesis, consist offour elementary steps. Polymers products that are commonly referred to as plastics by the general public are known to chemists as polymers. The initiator efficiency f as a function of monomer conversion was estimated via an equation relating the instantaneous and. Only monomers and small traces of initiators and additives are charged to the reactor.
The polymerization conforms to the fixed shape of the reaction vessel when solidification occurs. Bulk polymerization or mass polymerization is carried out by adding a soluble radical initiator to. As the reaction proceeds the mixture becomes more viscous. In solution or modified bulk polymerization, the reaction takes place as the monomer is dissolved in a small amount of solvent, such as ethylbenzene. Usually, bulk polymerization in ampoules is employed to study the kinetics of suspension polymerization reactions. Solution polymerization occur in existence of inert solvent and suitable catalyst, on the contrary of. Introduction the processes for manufacturing macromolecules can be divided into three different categories as shown in the scheme below.
These radicals can induce free radical sites on the hydroxyethyl cellulose backbone by hydrogen abstraction of the acetal hydrogen see scheme 1. The polymer is obtained in a convenient, easily handled, and often directly useful. Fundamentals of freeradical polymerization, heterogeneous polymerization, controlled radical polymerization, polymer reaction engineering, and polymer characterization. Polymerization techniques bulk polymerization the simplest technique, and gives the highestpurity polymer. Chemical engineering 160260 polymer science and engineering. Bulk polymerization the bulk addition polymerization is the simplest of all polymerization processes. Bulk polymerizations can proceed either homogenous or inhomogenous, depending on the solubility. Emulsion and casting or extrusion of free films by mechanical methods can also produce coatings and films. Polymerisation techniques polymerisation techniques used in the production of some commercial polymers. Once the reaction starts, heating is stopped as the reaction is exothermic. A somewhat less pure polymer than from bulk polymerisation, since there are bound to be remnants of the suspending agents adsorbed on the particle surface. Bulk polymerization has several advantages over other methods, these advantages are. In this process, the monomer and catalyst are poured into a mold where the reaction takes place.
Methods of polymerization polymerization reaction may take place in any of the three states of mattersolid, liquid, gas. Bulk polymerization an overview sciencedirect topics. Polymerization of all chains stops at identical molecular weights. The polymerization in bulk form was carried out in vacuum and in open atmosphere. Polymerization techniques bulk polymerization solution polymerization suspension polymerization emulsion polymerization bulk polymerization. Bulk polymerization bulk polymerization is carried out in the absence of any solvent or dispersant and is thus the simplest in terms of formulation. Polymerization techniques bulk polymerization solution polymerization suspension pearl polymerization emulsion polymerization bulk polymerization bulk addition polymerization is a homogeneous process which uses an organic initiator two possibilities.
Chain transfer to solvent occurs, leading to low molecular weights. It is used for most stepgrowth polymers and many types of chaingrowth polymers. Polymer polymerisation technique polyamides polycarbonates polyethylene terephthalates polysulphides polyethylene low density polyethylene high density polymethyl methacrylate polypropylene polystyrene polyvinyl acetate. Free radicals can be formed by a number of different mechanisms, usually involving separate initiator molecules.
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