Polybenzimidazole Synthesis from Compounds with Sulfonate Ester Linkages
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Controlled/Living Radical Polymerization in Aqueous Media: Homogeneous and Heterogeneous Systems
Prog. Polym. Sci. 26 =2001) 2083±2134 www.elsevier.com/locate/ppolysci Controlled/living radical polymerization in aqueous media: homogeneous and heterogeneous systems Jian Qiua, Bernadette Charleuxb,*, KrzysztofMatyjaszewski a aDepartment of Chemistry, Center for Macromolecular Engineering, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA bLaboratoire de Chimie MacromoleÂculaire, Unite Mixte associeÂe au CNRS, UMR 7610, Universite Pierre et Marie Curie, Tour 44, 1er eÂtage, 4, Place Jussieu, 75252 Paris cedex 05, France Received 27 July 2001; accepted 30 August 2001 Abstract Controlled/living radical polymerizations carried out in the presence ofwater have been examined. These aqueous systems include both the homogeneous solutions and the various heterogeneous media, namely disper- sion, suspension, emulsion and miniemulsion. Among them, the most common methods allowing control ofthe radical polymerization, such as nitroxide-mediated polymerization, atom transfer radical polymerization and reversible transfer, are presented in detail. q 2001 Elsevier Science Ltd. All rights reserved. Keywords: Aqueous solution; Suspension; Emulsion; Miniemulsion; Nitroxide; Atom transfer radical polymerization; Reversible transfer; Reversible addition-fragmentation transfer Contents 1. Introduction ..................................................................2084 2. General aspects ofconventional radical polymerization in aqueous media .....................2089 2.1. Homogeneous polymerization .................................................2089 -
Poly(Sodium Acrylate)-Based Antibacterial Nanocomposite Materials
Poly(Sodium Acrylate)-Based Antibacterial Nanocomposite Materials Samaneh Khanlari Thesis submitted to the Faculty of Graduate and Postdoctoral Studies in partial fulfillment of the requirements for the degree of Doctorate in Philosophy in Chemical Engineering Department of Chemical and Biological Engineering Faculty of Engineering UNIVERSITY OF OTTAWA © Samaneh Khanlari, Ottawa, Canada, 2015 i ii Abstract Polymer-based bioadhesives for sutureless surgery provide a promising alternative to conventional suturing. In this project, a new poly(sodium acrylate)-based nanocomposite with antibacterial properties was developed. Poly(sodium acrylate), was prepared using a redox solution polymerization at room temperature; this polymer served as a basis for a nanocomposite bioadhesive material using silver nanoparticles. In-situ polymerization was chosen as a nanocomposite synthesizing method and three methods were applied to quantify the distribution and loadings of nanofiller in the polymer matrices. These included the Voronoi Diagram, Euclidean Minimum Spanning Tree (EMST) method and pixel counting. Results showed that pixel counting combined with the EMST method would be most appropriate for nanocomposite morphology quantification. Real-time monitoring of the in-situ polymerization of poly(sodium acrylate)- based nanocomposite was investigated using in-line Attenuated Total Reflectance/Fourier Transform infrared (ATR-FTIR) technique. The ATR-FTIR spectroscopy method was shown to be valid in reaction conversion monitoring using a partial least squares (PLS) multivariate calibration method and the results were consistent with the data from off-line water removal gravimetric monitoring technique. Finally, a second, more degradable polymer (i.e., gelatin and poly(vinyl alcohol)) was used to modify the degradation rate and hydrophilicity of the nanocomposite bioadhesive. -
Synthesis and Characterization of Solution and Melt Processible Poly(Acrylonitrile-Co-Methyl Acrylate) Statistical Copolymers
SYNTHESIS AND CHARACTERIZATION OF SOLUTION AND MELT PROCESSIBLE POLY(ACRYLONITRILE-CO-METHYL ACRYLATE) STATISTICAL COPOLYMERS Padmapriya Pisipati Dissertation submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Macromolecular Science and Engineering James E. McGrath, Chair Judy S. Riffle, Acting Chair Eugene G. Joseph Sue J. Mecham Donald G. Baird 02/20/2015 Blacksburg, VA Keywords: melt processability, polyacrylonitrile, carbon fibers, methyl acrylate, acrylic fibers, plasticizer, solution processing, high tensile modulus Copyright 2015, Padmapriya Pisipati SYNTHESIS AND CHARACTERIZATION OF SOLUTION AND MELT PROCESSIBLE POLY (ACRYLONITRILE-CO-METHYL ACRYLATE) STATISTICAL COPOLYMERS ABSTRACT Padmapriya Pisipati Polyacrylonitrile (PAN) and its copolymers are used in a wide variety of applications ranging from textiles to purification membranes, packaging material and carbon fiber precursors. High performance polyacrylonitrile copolymer fiber is the most dominant precursor for carbon fibers. Synthesis of very high molecular weight poly(acrylonitrile-co-methyl acrylate) copolymers with weight average molecular weights of at least 1.7 million g/mole were synthesized on a laboratory scale using low temperature, emulsion copolymerization in a closed pressure reactor. Single filaments were spun via hybrid dry-jet gel solution spinning. These very high molecular weight copolymers produced precursor fibers with tensile strengths averaging 954 MPa with an elastic modulus of 15.9 GPa (N = 296). The small filament diameters were approximately 5 µm. Results indicated that the low filament diameter that was achieved with a high draw ratio, combined with the hybrid dry-jet gel spinning process lead to an exponential enhancement of the tensile properties of these fibers. -
Polymer Chemistry
CLOTHWORKERS LIBRARY UNIVERSITY OF LEEDS THERMAL AND OXIDATIVE DEGRADATION OF AN AROMATIC POLYAMIDE. by «. Shojan Nanoobhai Patel 2. Submitted in accordance with the requirement for the degree of Doctor of Philosophy under the supervision of Professor I.E. McIntyre and Dr. S.A. Sills. The candidate confirms that the work submitted is his own and that appropriate credit has been given where reference has been made to work of others. Department of Textile Industries, The University of Leeds, Leeds, LS2 9JT. December 1992. CLASS MARK T:; ~S 2tC\4 -1- ABSTRACT. The thermal oxidation of an aromatic polyamide fibre, namel\' poly(m-xylylene adipamide) has been investigated. The volatile and non-volatile products of oxidation identified using T.L.C., H.P.L.C. and G.C.-M.S. include homologous series of monocarboxylic acids, dicarboxylic acids, n-alkyl amines, diamines and aldehydes. Furthermore, several aromatics, ketones and amides were also identified. Mechanisms for their derivation have been proposed which are based on oxidation reactions already established in polymer chemistry. These include a mechanism of ~ scission by an alkoxy radical thought to be responsible for the creation of the homologous series. MXD,6 fibres were also spun incorporating 100, 200 and 400ppm of a cobalt catalyst and the effect of the metal ions on the oxygen uptake of the fibres was investigated. The results show a consistent increase in the rate of oxygen uptake as the concentration of the cobalt is increased. Furthermore, T.G.A. oxidative degradation studies, conducted at isothermal temperatures in the solid state, show decreases in the activation energies associated with fibre oxidation with increased cobalt concentrations, implying the cobalt is a catalyst for oxidation. -
1 050929 Quiz 1 Introduction to Polymers 1) in Class We Discussed
050929 Quiz 1 Introduction to Polymers 1) In class we discussed a hierarchical categorization of the terms: macromolecule, polymer and plastics, in that plastics are polymers and macromolecules and polymers are macromolecules; but all macromolecules are not polymers and all polymers are not plastics. a) Give an example of a macromolecule that is not a polymer. b) Give an example of a polymer that is not a plastic. c) Define polymer. d) Define plastic. e) Define macromolecule. 2) In class we observed a simulation of a small polymer chain of 40 flexible steps. The chain was observed to explore configurational space. a) Explain what the phrase "explore configurational space" means. b) Consider the two ends of the chain to be tethered with a separation distance of about 6 extended steps. If temperature were increased would the chain ends push apart or pull together the tether points? Explain why. c) If one chain end is fixed in Cartesian space at x = 0, what are the limits on the x-axis for the other chain end as it explores configurational space? d) What is the average value of the position on the x-axis? dγ 3) Polymer melts are processed at high rates of strain, , in an extruder, injection molder, or dt calander. a) Sketch a typical plot of polymer viscosity versus rate of strain on a log-log plot showing the power-law region and the Newtonian plateau at low rates of strain. b) Explain using this plot why polymers are processed at high rates of strain. c) Using your own words propose a molecular model that could explain shear thinning in polymers. -
Solution Polymerization of Acrylic Acid Initiated by Redox Couple Na-PS/Na-MBS: Kinetic Model and Transition to Continuous Process
processes Article Solution Polymerization of Acrylic Acid Initiated by Redox Couple Na-PS/Na-MBS: Kinetic Model and Transition to Continuous Process Federico Florit , Paola Rodrigues Bassam , Alberto Cesana and Giuseppe Storti * Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy; federico.fl[email protected] (F.F.); [email protected] (P.R.B.); [email protected] (A.C.) * Correspondence: [email protected] Received: 28 May 2020; Accepted: 14 July 2020; Published: 16 July 2020 Abstract: This work aims at modeling in detail the polymerization of non-ionized acrylic acid in aqueous solution. The population balances required to evaluate the main average properties of molecular weight were solved by the method of moments. The polymerization process considered is initiated by a persulfate/metabisulfate redox couple and, in particular, the kinetic scheme considers the possible formation of mid-chain radicals and transfer reactions. The proposed model is validated using experimental data collected in a laboratory-scale discontinuous reactor. The developed kinetic model is then used to intensify the discontinuous process by shifting it to a continuous one based on a tubular reactor with intermediate feeds. One of the experimental runs is selected to show how the proposed model can be used to assess the transition from batch to continuous process and allow faster scale-up to industrial scale using a literature approach. Keywords: Poly(acrylic acid); free-radical polymerization; reaction model; process intensification; semi-batch to continuous 1. Introduction Poly(acrylic acid) (PAA) is a widely produced polymer with a growing, global annual production of 1.58 109 kg as of 2008 [1] and with applications in many industrial sectors. -
Emulsion Polymerization
Emulsion Polymerization Reference: Aspen Polymers: Unit Operations and Reaction Models, Aspen Technology, Inc., 2013. 1. Introduction Emulsion polymerization is an industrially important process for the production of polymers used as synthetic rubber, adhesives, paints, inks, coatings, etc. The polymerization is usually carried out using water as the dispersion medium. This makes emulsion polymerization less detrimental to the environment than other processes in which volatile organic liquids are used as a medium. In addition, emulsion polymerization offers distinct processing advantages for the production of polymers. Unlike in bulk or solution polymerization, the viscosity of the reaction mixture does not increase as dramatically as polymerization progresses. For this reason, the emulsion polymerization process offers excellent heat transfer and good temperature throughout the course of polymer synthesis. In emulsion polymerization, free-radical propagation reactions take place in particles isolated from each other by the intervening dispersion medium. This reduces termination rates, giving high polymerization rates, and simultaneously makes it possible to produce high molecular weight polymers. One can increase the rate of polymerization without reducing the molecular weight of the polymer. Emulsion polymerization has more recently become important for the production of a wide variety of specialty polymers. This process is always chosen when the polymer product is used in latex form. 2. Reaction Kinetic Scheme To appreciate the complexities of emulsion polymerization, a basic understanding of the fundamentals of particle formation and of the kinetics of the subsequent particle growth stage is required. A number of mechanisms have been proposed for particle formation. It is generally accepted that any one of the mechanisms could be responsible for particle formation depending on the nature of the monomer and the amount of emulsifier used in the recipe. -
Living Free Radical Polymerization with Reversible Addition – Fragmentation
Polymer International Polym Int 49:993±1001 (2000) Living free radical polymerization with reversible addition – fragmentation chain transfer (the life of RAFT) Graeme Moad,* John Chiefari, (Bill) YK Chong, Julia Krstina, Roshan TA Mayadunne, Almar Postma, Ezio Rizzardo and San H Thang CSIRO Molecular Science, Bag 10, Clayton South 3169, Victoria, Australia Abstract: Free radical polymerization with reversible addition±fragmentation chain transfer (RAFT polymerization) is discussed with a view to answering the following questions: (a) How living is RAFT polymerization? (b) What controls the activity of thiocarbonylthio compounds in RAFT polymeriza- tion? (c) How do rates of polymerization differ from those of conventional radical polymerization? (d) Can RAFT agents be used in emulsion polymerization? Retardation, observed when high concentra- tions of certain RAFT agents are used and in the early stages of emulsion polymerization, and how to overcome it by appropriate choice of reaction conditions, are considered in detail. Examples of the use of thiocarbonylthio RAFT agents in emulsion and miniemulsion polymerization are provided. # 2000 Society of Chemical Industry Keywords: living polymerization; controlled polymerization; radical polymerization; dithioester; trithiocarbonate; transfer agent; RAFT; star; block; emulsion INTRODUCTION carbonylthio compounds 2 by addressing the following In recent years, considerable effort1,2 has been issues: expended to develop free radical processes that display (a) How living is RAFT polymerization? -
Emissions Factors & AP-42, CH 6: Organic Chemical Process Industry
6.9 Synthetic Fibers 6.9.1 General1-3 There are 2 types of synthetic fiber products, the semisynthetics, or cellulosics (viscose rayon and cellulose acetate), and the true synthetics, or noncellulosics (polyester, nylon, acrylic and modacrylic, and polyolefin). These 6 fiber types compose over 99 percent of the total production of manmade fibers in the U. S. 6.9.2 Process Description2-6 Semisynthetics are formed from natural polymeric materials such as cellulose. True synthetics are products of the polymerization of smaller chemical units into long-chain molecular polymers. Fibers are formed by forcing a viscous fluid or solution of the polymer through the small orifices of a spinnerette (see Figure 6.9-1) and immediately solidifying or precipitating the resulting filaments. This prepared polymer may also be used in the manufacture of other nonfiber products such as the enormous number of extruded plastic and synthetic rubber products. Figure 6.9-1. Spinnerette. Synthetic fibers (both semisynthetic and true synthetic) are produced typically by 2 easily distinguishable methods, melt spinning and solvent spinning. Melt spinning processes use heat to melt the fiber polymer to a viscosity suitable for extrusion through the spinnerette. Solvent spinning processes use large amounts of organic solvents, which usually are recovered for economic reasons, to dissolve the fiber polymer into a fluid polymer solution suitable for extrusion through a spinnerette. The major solvent spinning operations are dry spinning and wet spinning. A third method, reaction spinning, is also used, but to a much lesser extent. Reaction spinning processes involve the formation of filaments from prepolymers and monomers that are further polymerized and cross-linked after the filament is formed. -
Lecture36: Introduction to Polymerization Technology
NPTEL – Chemical – Chemical Technology II Lecture36: Introduction To Polymerization Technology 36. 1 Definitions and Nomenclature Polymer: Polymers are large chain molecules having a high molecular weight in the range of 103 to 107. These are made up of a single unit or a molecule, which is repeated several times within the chained structure. Monomer : A monomer is the single unit or the molecule which is repeated in the polymer chain. It is the basic unit which makes up the polymer. ThermosettingPolymer: There are some polymers which, when heated, decompose, and hence, cannot be reshaped. Such polymers have a complex 3-D network (cross-linked or branched) and are called Thermosetting Polymers. They are generally insoluble in solvents and have good heat resistance quality. Thermosetting polymers include phenol-formaldehyde, urea-aldehyde, silicones and allyls. ThermoplasticPolymer: The polymers in this category are composed of monomers which are linear or have moderate branching. They can be melted repeatedly and casted into various shapes and structures. They are soluble in solvents, but do not have appreciable thermal resistance properties. Vinyls, cellulose derivatives, polythene and polypropylene fall into the category of thermoplastic polymers. Joint initiative of IITs and IISc – Funded by MHRD Page 1 of 51 NPTEL – Chemical – Chemical Technology II 36.2 Polymer Classification Polymers are generally classified on the basis of – I. Physical and chemical structures. II. Preparation methods. III. Physical properties. IV. Applications. 36.3 Classification According To Physical And Chemical Structures : 1 .On the basis of functionality or degree of polymerization : The functionality of a monomer or its degree of polymerization determines the final polymer that will be formed due to the combination of the monomers. -
Preparation and Characterization of Water-Soluble Acrylic Pressure Sensitive Adhesive
Open Access Journal of Waste Management & Xenobiotics ISSN: 2640-2718 Preparation and Characterization of Water-soluble Acrylic Pressure Sensitive Adhesive Juhyeon L1 and Jaehee L2* Research Article 1Hankuk Academy of Foreign Studies, Korea Volume 1 Issue 2 Received Date: November 01, 2018 2Gaia Corporation, Korea Published Date: November 15, 2018 *Corresponding author: Jaehee Lee, Hankuk Academy of Foreign Studies, 32-36 DOI: 10.23880/oajwx-16000110 Yuseongdaero, 1596beon-gil, Yuseong-gu, Daejeon, 34054, Korea, Tel: +82 423849706; Email: [email protected] Abstract In order to evaluate the adhesion performance, tack, peel strength, shear strength, and water solubility of pressure- sensitive adhesive (PSA), we prepared PSA copolymers using 2-ethyl hexyl acrylate (2-EHA), butyl acrylate (BA) and acrylic acid (AA) with varying AA contents through solution polymerization in methanol. After preparing the PSAs, we neutralized the AA in the PSAs with potassium hydroxide (KOH). Polypropylene glycol (PPG) was blended with the PSAs as a surfactant before testing adhesion performance and water solubility. Tack was characterized by probe tack testing, shear strength was evaluated with these hear adhesion failure temperature (SAFT) method, and peel strength was measured by 180° peel testing. The water solubility test was performed by comparing weight of before immersing the PSA blends in distilled water and after removing the PSAs blends from water. Water solubility was increased along within creased AA and PPG contents in the PSA blends. Keywords: Water-Soluble; Pressure sensitive Adhesive; PSA; Acrylic Abbreviations: PSA: Pressure-Sensitive Adhesive; 2- problems in paper-making such a sit becoming stuck to EHA: 2-Ethylhexyl Acrylate; SAFT: Shear Adhesion Failure the felts, wires, and dryer cylinders of paper machines, Temperature; TAPPI: Technical Association of Pulp and thus causing web breaks, reducing production, and Paper Industry (TAPPI). -
Initiator Feeding Policies in Semi-Batch Free Radical Polymerization: a Monte Carlo Study
processes Article Initiator Feeding Policies in Semi-Batch Free Radical Polymerization: A Monte Carlo Study Ali Seyedi 1, Mohammad Najafi 1,* , Gregory T. Russell 2,* , Yousef Mohammadi 3,*, Eduardo Vivaldo-Lima 4 and Alexander Penlidis 5,* 1 Department of Polymer Engineering, School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran 1417466191, Iran; [email protected] 2 School of Physical and Chemical Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand 3 Petrochemical Research and Technology Company (NPC-rt), National Petrochemical Company (NPC), P.O. Box 14358-84711, Tehran 1993834557, Iran 4 Facultad de Química, Departamento de Ingeniería Química, Universidad Nacional Autónoma de México, CU, Mexico City 04510, Mexico; [email protected] 5 Department of Chemical Engineering, Institute for Polymer Research (IPR), University of Waterloo, Waterloo, ON N2L 3G1, Canada * Correspondence: najafi[email protected] (M.N.); [email protected] (G.T.R.); [email protected] (Y.M.); [email protected] (A.P.); Tel.: +519-888-4567 (ext. 36634) (A.P.) Received: 11 September 2020; Accepted: 3 October 2020; Published: 15 October 2020 Abstract: A Monte Carlo simulation algorithm is developed to visualize the impact of various initiator feeding policies on the kinetics of free radical polymerization. Three cases are studied: (1) general free radical polymerization using typical rate constants; (2) diffusion-controlled styrene free radical polymerization in a relatively small amount of solvent; and (3) methyl methacrylate free radical polymerization in solution. The number- and weight-average chain lengths, molecular weight distribution (MWD), and polymerization time were computed for each initiator feeding policy.