Polymer Exemption Guidance Manual POLYMER EXEMPTION GUIDANCE MANUAL
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2 a Primer on Polymer Colloids: Structure, Synthesis and Colloidal Stability
A. Al Shboul, F. Pierre, and J. P. Claverie 2 A primer on polymer colloids: structure, synthesis and colloidal stability 2.1 Introduction A colloid is a dispersion of very fine objects in a fluid [1]. These objects can be solids, liquids or gas, and the corresponding colloidal dispersion is then referred to as sus- pension, emulsion or foam. Colloids possess unique characteristics. For example, as their size is smaller than the wavelength of light, they scatter light. They also offer a large interfacial surface area, meaning that interfacial phenomena are of paramount importance in these dispersions. The weight of each dispersed particle being small, gravity and buoyancy forces are not sufficient to counteract the thermal random mo- tion of the particle, named Brownian motion (in tribute to the 19th century botanist Robert Brown who first characterized it). The particles do not remain in a dispersed state indefinitely: they will sooner or later aggregate (phase separation). Thus, thecol- loidal state is in general metastable and colloidal stability is one of the key features to take into account when working with colloids. Among all colloids, the polymer colloid family is one of the most widely inves- tigated [2]. Polymer colloids are used for a large number of applications, ranging from coatings, adhesives, inks, impact modifiers, drug-delivery vehicles, etc. The particles range in size from about 10 nm to 1 000 nm (1 μm) in diameter. They are usually spherical, but numerous other shapes have been observed. Polymer colloids are not uncommon in nature. For example, natural rubber latex, the secretion of the Hevea brasiliensis tree, is in fact a dispersion of polyisoprene nanoparticles in wa- ter. -
1 Fundamentals of Polymer Chemistry
1 Fundamentals of Polymer Chemistry H. Warson 1 THE CONCEPT OF A POLYMER 1.1 Historical introduction The differences between the properties of crystalline organic materials of low molecular weight and the more indefinable class of materials referred to by Graham in 1861 as ‘colloids’ has long engaged the attention of chemists. This class includes natural substances such as gum acacia, which in solution are unable to pass through a semi-permeable membrane. Rubber is also included among this class of material. The idea that the distinguishing feature of colloids was that they had a much higher molecular weight than crystalline substances came fairly slowly. Until the work of Raoult, who developed the cryoscopic method of estimating molecular weight, and Van’t Hoff, who enunciated the solution laws, it was difficult to estimate even approximately the polymeric state of materials. It also seems that in the nineteenth century there was little idea that a colloid could consist, not of a product of fixed molecular weight, but of molecules of a broad band of molecular weights with essentially the same repeat units in each. Vague ideas of partial valence unfortunately derived from inorganic chem- istry and a preoccupation with the idea of ring formation persisted until after 1920. In addition chemists did not realise that a process such as ozonisation virtually destroyed a polymer as such, and the molecular weight of the ozonide, for example of rubber, had no bearing on the original molecular weight. The theory that polymers are built up of chain formulae was vigorously advocated by Staudinger from 1920 onwards [1]. -
Oligomeric A2 + B3 Approach to Branched Poly(Arylene Ether Sulfone)
“One-Pot” Oligomeric A 2 + B 3 Approach to Branched Poly(arylene ether sulfone)s: Reactivity Ratio Controlled Polycondensation A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science By ANDREA M. ELSEN B.S., Wright State University, 2007 2009 Wright State University WRIGHT STATE UNIVERSITY SCHOOL OF GRADUATE STUDIES June 19, 200 9 I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPERVISION BY Andrea M. Elsen ENTITLED “One-Pot” Oligomeric A2 + B3 Approach to Branched Poly(arylene ether sulfone)s: Reactivity Ratio Controlled Polycondenstation BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master of Science . _________________________ Eric Fossum, Ph.D. Thesis Director _________________________ Kenneth Turnbull, Ph.D. Department Chair Committee on Final Examination ____________________________ Eric Fossum, Ph.D. ____________________________ Kenneth Turnbull, Ph.D. ____________________________ William A. Feld, Ph.D. ____________________________ Joseph F. Thomas, Jr., Ph.D. Dean, School of Graduate Studies Abstract Elsen, Andrea M. M.S., Department of Chemistry, Wright State University, 2009. “One-Pot” Oligomeric A 2 + B 3 Approach to Branched Poly(arylene ether sulfone)s: Reactivity Ratio Controlled Polycondensation The synthesis of fully soluble branched poly(arylene ether)s via an oligomeric A 2 + B 3 system, in which the A 2 oligomers are generated in situ, is presented. This approach takes advantage of the significantly higher reactivity toward nucleophilic aromatic substitution reactions, NAS, of B 2, 4-Fluorophenyl sulfone, relative to B 3, tris (4-Fluorophenyl) phosphine oxide. The A 2 oligomers were synthesized by reaction of Bisphenol-A and B 2, in the presence of the B 3 unit, at temperatures between 100 and 160 °C, followed by an increase in the reaction temperature to 180 °C at which point the branching unit was incorporated. -
And Ph-Dependent Oligomerization of the Thrombin-Derived C-Terminal Peptide TCP-25
biomolecules Article Concentration- and pH-Dependent Oligomerization of the Thrombin-Derived C-Terminal Peptide TCP-25 Ganna Petruk 1,* , Jitka Petrlova 1, Firdaus Samsudin 2 , Rita Del Giudice 3 , Peter J. Bond 2,4 and Artur Schmidtchen 1,5,6 1 Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, 22241 Lund, Sweden; [email protected] (J.P.); [email protected] (A.S.) 2 Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore 138671, Singapore; [email protected] (F.S.); [email protected] (P.J.B.) 3 Research Centre for Biointerfaces, Department of Biomedical Sciences and Biofilms, Malmö University, 20506 Malmö, Sweden; [email protected] 4 Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore 5 Copenhagen Wound Healing Center, Bispebjerg Hospital, Department of Biomedical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark 6 Dermatology, Skane University Hospital, 22185 Lund, Sweden * Correspondence: [email protected]; Tel.: +46-46-22-23-315 Received: 18 October 2020; Accepted: 9 November 2020; Published: 19 November 2020 Abstract: Peptide oligomerization dynamics affects peptide structure, activity, and pharmacodynamic properties. The thrombin C-terminal peptide, TCP-25 (GKYGFYTHVFRLKKWIQKVIDQFGE), is currently in preclinical development for improved wound healing and infection prevention. It exhibits turbidity when formulated at pH 7.4, particularly at concentrations of 0.3 mM or more. We used biochemical and biophysical approaches to explore whether the peptide self-associates and forms oligomers. The peptide showed a dose-dependent increase in turbidity as well as α-helical structure at pH 7.4, a phenomenon not observed at pH 5.0. -
Cinnamoyl Esters of Lesquerella and Castor Oil: Novel Sunscreen Active Ingredients David L
Cinnamoyl Esters of Lesquerella and Castor Oil: Novel Sunscreen Active Ingredients David L. Compton*, Joseph A. Laszlo, and Terry A. Isbell New Crops and Processing Technology Research Unit, USDA, ARS, NCAUR, Peoria, Illinois 61604 ABSTRACT: Lesquerella and castor oils were esterified with querolin (2). Therefore, LO in essence contains two moles of cinnamic acid (CA) and 4-methoxycinnamic acid (MCA). Esteri- hydroxy functionality per mole of triglyceride (TG). fication of the hydroxy oils reached 85% completion with CA The hydroxy functionality of the FA of the TG can be ex- and 50% conversion with MCA. The hydroxy oils were esteri- ploited by esterification to form estolides. The majority of re- fied at 200°C under a nitrogen atmosphere within a sealed sys- search has focused on the estolides of hydroxy FA and TG tem. Unreacted CA and MCA were removed from the reaction formed with oleic acid. The esterification of hydroxy TG and mixtures by sublimation at 100°C under vacuum. The resultant free lesquerolic acid with oleic acid using a cobalt catalyst (4) methoxycinnamic oils possessed a broader, more blue-shifted or a lipase catalyst (5) has been reported. Also, the acid-cat- UV absorbance, 250 to 345 nm with a λmax of 305 nm, com- pared with the cinnamic oils, which absorbed from 260 to 315 alyzed formation of estolides from CO and LO with oleic acid has been patented (6). Recently, a detailed study of the effect nm, λmax of 270 nm. The methoxycinnamic oils provide better UV-B absorption and thus are better candidates to be used as of oleic acid concentration and temperature on catalyst-free sunscreen active ingredients. -
Structural Mechanisms of Oligomer and Amyloid Fibril Formation by the Prion Protein Cite This: Chem
ChemComm View Article Online FEATURE ARTICLE View Journal | View Issue Structural mechanisms of oligomer and amyloid fibril formation by the prion protein Cite this: Chem. Commun., 2018, 54,6230 Ishita Sengupta a and Jayant B. Udgaonkar *b Misfolding and aggregation of the prion protein is responsible for multiple neurodegenerative diseases. Works from several laboratories on folding of both the WT and multiple pathogenic mutant variants of the prion protein have identified several structurally dissimilar intermediates, which might be potential precursors to misfolding and aggregation. The misfolded aggregates themselves are morphologically distinct, critically dependent on the solution conditions under which they are prepared, but always b-sheet rich. Despite the lack of an atomic resolution structure of the infectious pathogenic agent in prion diseases, several low resolution models have identified the b-sheet rich core of the aggregates formed in vitro, to lie in the a2–a3 subdomain of the prion protein, albeit with local stabilities that vary Received 17th April 2018, with the type of aggregate. This feature article describes recent advances in the investigation of in vitro Accepted 14th May 2018 prion protein aggregation using multiple spectroscopic probes, with particular focus on (1) identifying DOI: 10.1039/c8cc03053g aggregation-prone conformations of the monomeric protein, (2) conditions which trigger misfolding and oligomerization, (3) the mechanism of misfolding and aggregation, and (4) the structure of the misfolded rsc.li/chemcomm intermediates and final aggregates. 1. Introduction The prion protein can exist in two distinct structural isoforms: a National Centre for Biological Sciences, Tata Institute of Fundamental Research, PrPC and PrPSc. -
Terephthalic Acid and Dimethyl Terephthalate Supplement B
Report No. 9B TEREPHTHALIC ACID AND DIMETHYL TEREPHTHALATE SUPPLEMENT B by LLOYD M. ELKIN With contributions by Shigeyoshi Takaoka Kohsuke Ohta September 1970 e A private report by the PROCESS ECONOMICS PROGRAM STANFORD RESEARCH INSTITUTE MENLO PARK, CALIFORNIA e I CONTENTS 1 INTRODUCTION . 1 2 SUMMARY........................... 3 3 INDUSTRY STATUS . 13 4 CHEMISTRY......................... 23 Terephthalic Acid from p-Xylene by Liquid Phase Oxidation in the Presence of Large Amounts of Catalyst . 23 Bis(2-hydroxyethyl) Terephthalate from Ethylene Oxide and Terephthalic Acid . , . , . 25 Ammoxidation of p-Xylene . 26 dlycolysis of Terephthalonitrile . 28 Terephthalic Acid by Bromine-Promoted Catalytic Oxidation of p-Xylene ., . 30 Terephthalic Acid by Catalytic Oxidation of p-Xylene in the Presence of Methyl Ethyl Ketone Activator . 32 Terephthalic Acid by Nitric Acid Oxidation of p-Xylene . 32 Terephthalic Acid from Phthalic Anhydride . 33 5 REVIEW OF PATENTS . , . 37 Terephthalic Acid by Bromine-Promoted Catalytic Air Oxidation of p-Xylene . , . 37 Terephthalic Acid by Catalytic Oxidation of p-Xylene in the Presence of Activators . 38 Dimethyl Terephthalate from p-Xylene by Successive Oxidations and Esterifications . , . 39 Terephthalic Acid by Nitric Acid Oxidation of p-Xylene . 40 Terephthalic Acid from p-Xylene by Liquid Phase Oxidation in the Presence of Large Amounts of Catalyst . , . 40 Terephthalic Acid from p-Xylene by Other Oxidation Processes . , . , 42 Terephthalic Acid from Phthalic Anhydride or Benzoic Acid . 42 Terephthalonitrile, Preparation and Purification . 42 Dimethyl Terephthalate by Esterification of Terephthalic Acid.......................... 43 Bis(2-hydroxyethyl) Terephthalate from Terephthalic Acid and Ethylene Oxide or from Terephthalonitrile . 44 Purification of Terephthalic Acid . 44 Miscellaneous . 45 CONTENTS 6 TEREPHTHALIC ACID FROM p-XYLENE BY LIQUID PHASE OXIDATION IN THE PRESENCE OF LARGE AMOUNTS OF CATALYST , , . -
Entropy Driven Phase Transition in Polymer Gels: Mean Field Theory
entropy Article Entropy Driven Phase Transition in Polymer Gels: Mean Field Theory Miron Kaufman Physics Department, Cleveland State University, Cleveland, OH 44115, USA; [email protected] Received: 16 April 2018; Accepted: 27 June 2018; Published: 30 June 2018 Abstract: We present a mean field model of a gel consisting of P polymers, each of length L and Nz polyfunctional monomers. Each polyfunctional monomer forms z covalent bonds with the 2P bifunctional monomers at the ends of the linear polymers. We find that the entropy dependence on the number of polyfunctional monomers exhibits an abrupt change at Nz = 2P/z due to the saturation of possible crosslinks. This non-analytical dependence of entropy on the number of polyfunctionals generates a first-order phase transition between two gel phases: one poor and the other rich in poly-functional molecules. Keywords: crosslinking entropy; saturation; discontinuous phase transition 1. Motivation A polymer gel like polyacrylamide changes the volumes by a large factor of ~1000 when a small quantity of solvent like acetone is added to the solution or when the temperature is varied slightly. Central to the understanding of this phase transition are the covalent crosslinks [1–5] between the linear chains. Polymer chains, such as in hydroxypropylcellulose (HPC) immersed in a water solution, form hydrogen bonds with the water. As the temperature, the pH, or some other external condition is varied, there is a change in the strength of the hydrogen bonds that results in the formation or destruction of aggregates of crosslinked polymer chains. Light scattering experiments [6,7] are used to study the influence of the amount of crosslinkers on the properties of the gel phases. -
LIBRARY. This Thesis Has Been Approved for the Department of Chemical Engineering and the College of Engineering and Technology
~.. STUDY OF A COUNTER-ROTATING, INTERMESHING EXTRUDER AS A POLYCONDENSATION REACTOR /" A Thesis Presented to the Faculty of The College of Engineering and Technology Ohio University In Partial Fulfilment of the Requirements for the Degree Master of Science by Edward R. Crowe November, 1992 LIBRARY. This Thesis has been approved for the Department of Chemical Engineering and the College of Engineering and Technology Associate Prof Chem1cal Engineering Dean of the College of Engineering and Technology iii Abstract An experimental study and model development have been performed to better understand the reactive extrusion of polyethylene terephthalate. A process was developed using a 34 mm counter-rotating twin screw extruder to depolymerize a commercial grade of polyethylene terephthalate into an acceptable pre-polymer for reactive extrusion experiments. Residence time d Ls'tr Ibut.Lon experiments were conducted at different screw speeds and feed rates to characterize the flow patterns of the extruder. Based on these results an idealized plug-flow model was developed to simulate this process. An experimental design using the controllable process variables of zone temperature, feed rate and nitrogen flow sweeping across the surface of the polymer melt was developed to stUdy the individual effects of each of these variables as well as any interactive effects. The results indicate that the feed rate and nitrogen flow have an effect on the degree of polymerization of the product. However, the stUdy clearly shows the dominant effect to be ,the average residence time of the polymer melt in the vent zone. The idealized plug-flow model presents a reasonable representation of this process. -
HDPE: High Density Polyethylene LDPE
Abbreviations: HDPE: high density polyethylene LDPE: low density polyethylene PET: polyethylene terephthalate PP: polypropylene PS: polystyrene PVA: polyvinyl alcohol PVC: polyvinyl chloride addition polymerization: a chemical reaction in which simple molecules are linked together to form long chain molecules. amorphous: non-crystalline polymer or non-crystalline areas in a polymer. Bakelite: a polymer produced by the condensation of phenol and formaldehyde. branched polymer: polymer having smaller chains attached to the polymer backbone. cellulose: a natmal polymer found in wood and other plant material. composite polymer: a filled or reinforced plastic. condensation polymer: one in which two or more molecules combine resulting in elimination of water or other simple molecules, with the process being repeated to form a long chain molecule. configuration: related chemical structme produced by the making and breaking ofprimary valence bonds. copolymer: a macromolecule consisting of more than one type of building unit. creep: cold flow of a polymer. cross-linking: occms when primary valence bonds are formed between separate polymer molecules. crystalline polymer: polymer with a regular order or pattern of molecular arrangement and a sharp melting point. dimer: a polymer containing two monomers. domains: sequences or regions in block copolymers. elastomer: a type of polymer that exhibits rubber-like qualities. Ekonol: a moldable, high temperatme polymer. end group: functional group at the end of a chain in polymers, e.g. carboxylic group. extrusion: a fabrication process in which a heat-softened polymer is forced continually by a screw through a die. filler: a relatively inert material used as the discontinuous phase of a polymer composite. free radical: A chemical component that contains a free electron which covalently bonds with a free electron on another molecule. -
Synthesis of Polyesters by the Reaction of Dicarboxylic Acids with Alkyl Dihalides Using the DBU Method
Polymer Journal, Vol. 22, No. 12, pp 1043-1050 (1990) Synthesis of Polyesters by the Reaction of Dicarboxylic Acids with Alkyl Dihalides Using the DBU Method Tadatomi NISHIKUBO* and Kazuhiro OZAKI Department of Applied Chemistry, Faculty of Engineering, Kanagawa University, Rokkakubashi, Kanagawa-ku, Yokohama 221, Japan (Received July 6, 1990) ABSTRACT: Some polyesters with moderate viscosity were synthesized by reactions of dicarboxylic acids with alkyl dihalides using 1,8-diazabicyclo-[5.4.0]-7-undecene (DBU) in aprotic polar solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) under relatively mild conditions. The viscosity and yield of the resulting polymer increased with increasing monomer concentration. Although polymers with relatively high viscosity were obtained when the reaction with p-xylylene dichloride was carried out at 70°C in DMSO, the viscosity of the resulting polymers decreased with increasing reaction temperature when the reaction with m-xylylene dibromide was carried out in DMSO. KEY WORDS Polyester Synthesis/ Dicarboxylic Acids/ Alkyl Dihalides / DBU Method / Mild Reaction Condition / Although poly(ethylene terephthalate) is favorable method for the synthesis of polyes synthesized industrially by transesterification ters because the preparation and purification between dimethyl terephthalate and ethylene of the activated. dicarboxylic acids is un glycol at relatively high temperatures using necessary. certain catalysts, many polyesters are usually Some polyesters have also been prepared8 prepared by the polycondensation of dicarbox by reactions between alkali metal salts of ylic-acid chlorides with difunctional alcohols dicarboxylic-acids and aliphatic dibromides or phenols. These reactions are carried out using phase transfer catalysis (PTC)s, which is under relatively mild conditions; however, the a very convenient method for chemical activated dicarboxylic-acid chlorides must be modification, especially esterification9 or ether prepared and purified before the reaction. -
Soft Condensed Matter Physics Programme Course 6 Credits Mjuka Material TFYA37 Valid From: 2018 Spring Semester
1(9) Soft Condensed Matter Physics Programme course 6 credits Mjuka material TFYA37 Valid from: 2018 Spring semester Determined by Board of Studies for Electrical Engineering, Physics and Mathematics Date determined LINKÖPING UNIVERSITY FACULTY OF SCIENCE AND ENGINEERING LINKÖPING UNIVERSITY SOFT CONDENSED MATTER PHYSICS FACULTY OF SCIENCE AND ENGINEERING 2(9) Main field of study Applied Physics, Physics Course level Second cycle Advancement level A1X Course offered for Biomedical Engineering, M Sc in Engineering Engineering Biology, M Sc in Engineering Entry requirements Note: Admission requirements for non-programme students usually also include admission requirements for the programme and threshold requirements for progression within the programme, or corresponding. Prerequisites Mandatory courses in mathematics and physics for the Y-program or equal. Intended learning outcomes The course will ive the student knowledge of the statistical physics of polymers, the chemical, geometrical and electronic structure of polymers as well as the structure, dynamics and processing of polymer solids. We will discuss condensed matter in the form of colloids, amphiphiles, liquid crystals, molecular crystals and biological matter. After the course, the student should be able to describe the geometry of polymer chains and their dynamics, and the mathematical description of these phenomena utilize thermodynamical analysis of phase transitions in polymers and polymer blends LINKÖPING UNIVERSITY SOFT CONDENSED MATTER PHYSICS FACULTY OF SCIENCE AND ENGINEERING 3(9) describe micro and nanostructure of polymer solutions and polymer blends describe amphiphile materials, colloids, foams and gels, liquid crystals Course content Polymers: terminology, chemical structures and polymerization, solid state structures, polymers in solution, colligative properties. Statistical physics of polymer chains: random coils, entropy measures, rubber physics.