Autooxidation of Polymers
utility of the polymer.Polyethers,as a class,can undergo chain cleavage via autooxidation.Therefore,storage stability is an important consideration when formulating with POLYOX WSR polymers.The rate of autooxidation can be minimized through the addition of antioxidants and by controlling storage conditions.Key PointsThermal Oxidation of Polypropylene and Modified 2.1 The kinetics and mechanism of autooxidation of sol id polymers Three types reactions can be in the polymers in the presence of oxygen.1) Separately occurring molecule reactions.2) The radical - chain mechanism 3) The products of thermal decomposition and oxidation of polymers catalyze further decomposition of the polymer.The mechanism of polyethylene oxidation - Baum - 1959 As evidenced by formation of peroxides and carbonyl,reaction occurs during the oxidation induction period of polyethylene.The meaning of the term oxidation induction period is revealed by the tremendous change in melt index,carbonyl,density,color,tensile,and elongation occurring towards the end of this time period.
The in vivo auto-oxidation of polyether polyurethane by metal ions.Stokes K(1),Urbanski P,Upton J.Author information (1)Medtronic,Inc.,Minneapolis,MN 55432.The first large scale use of polyether polyurethane elastomers in long term human implants was as insulation for cardiac and neurologic pacing leads.The in vivo auto-oxidation of polyether polyurethane by The first large scale use of polyether polyurethane elastomers in long term human implants was as insulation for cardiac and neurologic pacing leads.While the performance of these polymers has generally been very good over a 14-year period,several failure mechanisms have been discovered that involThe in vivo auto-oxidation of polyether polyurethane by (1989).The in vivo auto-oxidation of polyether polyurethane by metal ions.Journal of Biomaterials Science,Polymer Edition Vol.1,No.3,pp.207-230.
polymer chain occurs via hydrogen atom transfer with a peroxyl radical.However,this reaction is strongly thermodynamically disfavored for all but unsaturated polymers,where the product allylic radical is resonance stabilized.Paradoxically,there is no denying that the autocatalytic degradation and oxidation of saturated polymers still occurs.School of Polymer Science and Engineering The University Feb 22,2021 Autooxidation of Polymers#0183;School of Polymer Science and Engineering Polymer science and engineering is a multidisciplinary STEM field focused on this special class of molecules.Polymer materials are ubiquitous in almost every aspect of modern life,and advances in the field enable scientific and technological breakthroughs in a wide range of technical applications.Review Auto-oxidation of aliphatic polyamides RequestPolyamide 11 (PA 11) is a semicrystalline high-performance thermoplastic engineering polymer with increasing production volume due to its balanced property profile and since it
oxidation of metalsauto oxidation removaloxidation of aluminumSome results are removed in response to a notice of local law requirement.For more information,please see here.Previous123456NextRelated searches for auto oxidation of polymersoxidation of metalsauto oxidation removaloxidation of aluminumSome results are removed in response to a notice of local law requirement.For more information,please see here.12345NextOpen Research Revising the mechanism of polymer autooxidationThe basic scheme for autooxidation of polymers,originally developed by Bolland,Gee and co-workers for rubbers and lipids,is now widely applied to all types of polymeric materials.According to their scheme,the reaction that makes this process autocatalytic,referred to as the propagation step,is a hydrogen abstraction from the next Products Trigon Antioxidants Pvt.Ltd.Our Products.Trigon Antioxidants is engaged in the manufacture of Thioesters has been in operation since 2010.The effort and emphasis of the Trigon Antioxidants is to ensure consistent high quality products with a commitment to regular and scheduled supplies.
The melted polymers and nanoclay powder were mixed at a screw speed of 125 rpm; temperature was increased from 150 Autooxidation of Polymers#176;C in the feeding zone up to 165 Autooxidation of Polymers#176;C at the nozzle for PHA1005 and PHA3002 (P3HB-co-P4HB formulations) and slightly decreased from 140 Autooxidation of Polymers#176;C in the feeding zone up to 160 Autooxidation of Polymers#176;C at the nozzle when blending PHB226 (P3HB).The compound Polymers Free Full-Text Reducing off-Flavour in Polyhydroxyalkanoates (PHAs) are nowadays considered competent candidates to replace traditional plastics in several market sectors.However,commercial PHA materials exhibit unsatisfactory smells that can negatively affect the quality of the final product.The cause of this typical rancid odour is attributed to oxidized cell membrane glycolipids,coming from GramPolymer Properties Database - polymerdatabasePhenolic antioxidants inhibit autooxidation of organic polymers by reducing the amount of peroxyl radicals during processing,storage and service.They are strong hydrogen / electron donors and,in addition,their radical intermediates are relatively stable due to aromatic resonance stabilization of the unpaired electron.
Jul 09,2020 Autooxidation of Polymers#0183;The combined action of ultraviolet (UV) radiation and oxygen on PE-HD is widely understood and here termed as photo-oxidative degradation 1,which follows the autoPhoto-oxidation of PE-HD affecting polymer/fuel Jul 09,2020 Autooxidation of Polymers#0183;Fuel sorption kinetics on photo-oxidized PE-HD.Several studies showed that semi-crystalline PE-HD can absorb fuel,e.g.petroleum diesel 18,19,20,23 and BD 17,18,19,20.Changes of the fuel Phosphite Antioxidants Additives for polymers ADEKA Phosphites are efficient decomposers of hydroperoxides that are formed during the autooxidation of polymers.Phosphites are especially used in melt processing where they are added in blends with hindered phenolic antioxidants.Such combinations are
THE oxidation under mild conditions of unsaturated compounds presents many unknown aspects,particularly with respect to the reaction mechanism.The primary products ofOxidation and Stabilisation of Polyethylenepolymers,and of UHMWPE in particular derive from the long molecular chains,anything which breaks those chains can have a very profound effect on properties n = 40,000 n = 20,000 Percentage of C atoms reacted = 0.003.Formation of free-radicals Energy from:Oxidation and Stabilisation of Polyethylenepolymers,and of UHMWPE in particular derive from the long molecular chains,anything which breaks those chains can have a very profound effect on properties n = 40,000 n = 20,000 Percentage of C atoms reacted = 0.003.Formation of free-radicals Energy from:
On the Mechanism of Autoxidation of Three Vinyl Polymers Polypropylene,Ethylene-Propylene Rubber,and Poly (ethyl acrylate)MSE 580 Koch Lec.13 - Nc State UniversityThus,they inhibit autooxidation of organic polymers by reducing the amount of peroxyl radicals.The mechanism of scavenging peroxy radicals is shown below for butylated hydroxytoluene (2,6-di-tert-butyI-4-methyIphenoI,BHT) SUMMARY PHENOLIC ANTIOX are the most widely us antioxidants.They cauLITERATURE REVIEW EFFECT OF ClO ON AGEING OFthat will initiate the degradation of the polymer.How this is formed is not fully understood,but it has been suggested that it involves proton and electron transfer with a phenolic antioxidant.One of the authors own research indicates that ClO2 accelerates the auto-oxidation of the polymer
This article is cited by 21 publications.Darren Conboy,Styliana I.Mirallai,Austin Craig,Patrick McArdle,Ali A.Al-Kinani,Stephen Barton,Fawaz Aldabbagh.Incorporating Morpholine and Oxetane into Benzimidazolequinone Antitumor Agents The Discovery of 1,4,6,9-Tetramethoxyphenazine from Hydrogen Peroxide and Hydroiodic Acid-Mediated OxidativeIrgafos Autooxidation of Polymersfor PlasticsIrgafos Autooxidation of Polymersprocessing stabilizers and blends thereof are the market reference recommended to ensure processing stability (color and viscosity retention).They protect polymers from thermo-oxidative degradation during processing.As a secondary antioxidant,they react with hydroperoxides formed by auto-oxidation of polymers,preventing process inducedIntroduction of Polymer additives ChemicalIn general,the same polymer stabilizers are used in most plastics,such as polypropylene,polyethylene,acrylonitrile butadiene styrene (ABS),and engineering plastics.The key to preventing the oxidative degradation of plastics is to terminate the radical reaction in the early stage of degradation,thereby terminating autoxidation.
Antioxidant action of flavonoids and polyphenolics was analyzed in relation to iron coordination.Flavonoids including baicalein,baicalin,quercetin,and rutin showed little or no reducing activity,and enhanced the autooxidation of Fe2+ ion.Ascorbate-mediatedInhibition of 1,2,4-benzenetriol-generated active oxygen Dec 22,1995 Autooxidation of Polymers#0183;Autooxidation of polyphenolic metabolites of benzene,such as hydroquinone (HQ),catechol (CT),1,2,4-benzenetriol (BT) and pyrogallol (PG),produced several kinds of active oxygen species (AOS).BT and PG induced DNA breaks in the absence of metal ions,especially when producing AOS such as H2O2,O2-,HO.or 1 delta gO2.Influence of allyl ethers on free radical polymerization Corresponding Author.Department of Polymer Technology,The Royal Institute of Technology,S100 44 Stockholm,Sweden.Department of Polymer Technology,The Royal Institute of Technology,S100 44 Stockholm,SwedenSearch for more papers by this author
In polymers,auto-oxidation,or autoxidation,is caused by the creation of free radicals(reactive molecular species with unpaired electrons).Autoxidation is a circular,self-propagating process that,unless interfered with by AOs,gradually leads to increasing degradation of the polymer.Reference sciencedirect/topics/engineering/auto-oxidationWas this helpful?People also askWhat is auto oxidation in polymers?What is auto oxidation in polymers?In polymers,auto-oxidation,or autoxidation,is caused by the creation of free radicals (reactive molecular species with unpaired electrons).Autoxidation is a circular,self-propagating process that,unless interfered with by AOs,gradually leads to increasing degradation of the polymer.Auto-Oxidation - an overview ScienceDirect TopicsImages of Auto Oxidation of Polymers
researchgate.netGeneral polymer auto-oxidation process.Download researchgate.netSchematic representation of polymer auto-oxidation and researchgate.net3 Polymer autooxidation cycle.(Idea from Van Beusichem,B researchgate.net(PDF) Revising the mechanism of polymer autooxidation images(PDF) Revising the mechanism of polymer autooxidationautooxidation in polymers is a k ey to developing strategies for the pr evention of their degradation.INTRODUCTION TO POLYMER ADDITIVES ANDWithout the use of the proper stabilization package,polymers will degrade.Interaction with oxygen and light can cause significant degradation of the polymer.These degradation products are potential leachables and extractables.Often,blends of stabilizers will be used to protect the polymer at various stages throughout the polymer lifecycle.
Sep 27,2012 Autooxidation of Polymers#0183;Such polymers are far more stiff than linear polymers,rather like an I-beam compared to a solid round rod of the same weight.They formed the gel at room temperature,and were able to achieve Engineers find antioxidants improve nanoscale Jan 08,2021 Autooxidation of Polymers#0183;Polymers are made up of molecular chains lying on top of each other.The previously imaged distance of 16 angstroms was the distance between chains,but imaging at 3.6 angstroms allowed Effect of the Prodegradant-Additive Plastics Incorporated The effect of degraded plastic with prodegradants on the polyethylene properties was studied.First,the mixture of low-density polyethylene (LDPE) with 5 wt.% prodegradant (oxo-degradable) additive was prepared by melt processing using a mixer chamber.Then,the degradation of the mixtures was evaluated by exposing the oxo-degradable LDPE in a Xenon arc chamber for
The effect of degraded plastic with prodegradants on the polyethylene properties was studied.First,the mixture of low-density polyethylene (LDPE) with 5 wt.% prodegradant (oxo-degradable) additive was prepared by melt processing using a mixer chamber.Then,the degradation of the mixtures was evaluated by exposing the oxo-degradable LDPE in a Xenon arc chamber forDegradation of Highly Elastic Polymers Rubber Chemistry The inhibited autooxidation of 1,5-polyenes was studied by means of intermittent relaxation in oxygen,using natural rubber crosslinked by CC links.The frequency and temperature conditions were so chosen that no degradation would have taken place in nitrogen.Controlled Radical Polymerization toward Ultra-High new polymer chain rather than to interact with CTA at a low concentration of CTA.Therefore,it is challenging to synthesize UHMW polymers by using external free radical initiators.Trialkylborane is known as a universal radical initiator under a variety of reaction temperatures and solvents owing to the formation of the alkyl radical from the
Cited by 140Publish Year 2011Author Ganna Gryn'ova,Jennifer L.Hodgson,Michelle L.CooteAutooxidation of Polymers - polymerdatabase
Oxidative degradation is usually initiated when polymer chains form radicals,either by hydrogen abstration or by homolytic cleavage of a carbon-carbon bonds.The cleavage of C-C and C-H bonds requires considerable energes and,thus,is often the rate determining step of the auto-catalyzed oxidation of plastics.Chemicals and Nature Auto-oxidation mechanismJun 26,2011 Autooxidation of Polymers#0183;Auto-oxidation mechanism Degradation of polymers by chemical reactions is a typical consecutive property and chemical changes occur due to reaction with components in the environment.The most important of these degrading reagents is oxygen.Oxidation may be induced and accelerated by radiation (photo-oxidation) or by thermal energy (thermal Bionox DSTDP - Bioray Chem - datasheet - Polymer AdditivesDecomposes and neutralizes hydroperoxides,formed by auto-oxidation of polymers.Is an efficient stabilizer for polyolefins,particularly PP and HDPE.Can be used as a synergist in combination with phenolic antioxidants.Enhances aging and light stability.Used for plastics,rubber and synthetic fiber.
Organic materials react with molecular oxygen in a process called autoxidation.Autoxidation is initiated by heat,light (high energy radiation),mechanical stress,catalyst residues,or reaction with impurities to form alkyl radicals.The free radical can,in turn,react and result in the degradation of the polymer.This is depicted below:Autoxidation or autooxidation SpringerLink\ Autooxidation of Polymers#243;- Autooxidation of Polymers#166; t Autooxidation of Polymers#228;k-s- Autooxidation of Polymers#166; d-shn\ (1883) n.Oxidation by direct combination with molecular oxygen (as in air) at ordinary temperatures as described in.The reaction of diatomic oxygen (O 2) with -bonds to form intermediate peroxides,etc.and permanent chemical bonds that are responsible for drying or curing of oils in alkyd resins (e.g.,the drying of linseed oil).Autoxidation of polymers SpringerLinkn.The reaction of oxygen with polymers to form peroxides,etc.,which can result in crosslinking and/or degradation.
Jan 30,2021 Autooxidation of Polymers#0183;Autoxidation Last updated January 30,2021.Autoxidation (sometimes auto-oxidation) refers to oxidations brought about by reactions with oxygen at normal temperatures,without the intervention of flame or electric spark. The term is usually used to describe the degradation of organic compounds in air at ambient temperatures.Many common phenomena can be attributed to autoxidationAutooxidation definition of autooxidation by Medical autooxidation ( aw't-oks'i-d'shn ),The direct combination of a substance with molecular oxygen at ordinary temperatures.Synonym(s) autoxidationAutooxidation and stabilization of undoped and doped Autooxidation is much slower if the polymer is compressed to higher bulk density.Radical scavengers such as BHT and 4010 are effective stabilizers.Hydroperoxide decomposers,such as DSTDP,does not help in the stabilization; spin trap BPN
Whereas autoxidation transfers drying oils into a polymer network,and thermal stress under oxidizing conditions (caustic oxidation,ozonolysis,or chromic acid oxidation) results in cleavage at the double bonds and formation of lower MW dicarboxylic acids,well-defined dicarboxylic acids with twice the number of carbon atoms as the starting acid (called dimer acid) are obtained byAuto-Oxidation - an overview ScienceDirect TopicsAgeing caused by temperature and humidity is a long-term effect for degradation in the performance of polymers.In general,the specified environment temperature does not suffice for thermal bond rupture of the polymer chains.Therefore the auto-oxidation processes and the formation of free radicals in the material are a critical factor.Antioxidants Additives for polymers ADEKA Polymer Phosphites are efficient decomposers of hydroperoxides that are formed during the autooxidation of polymers.Phosphites are especially used in melt processing where they are added in blends with hindered phenolic antioxidants.Such combinations are
Alkyd resins are a common and preferred class of polymers that dry by auto-oxidation.Alkyds are typically manufactured from unsaturated fatty acid residue containing esters which are prepared from the reaction of a polyhydric alcohol,a polybasic acid and a drying oil.Alkyd resins are well known in the art.(PDF) Oxidation reactions of tetrafluoroethylene and their Although its C F 0 ratio was the same as that of the copolymer obtained by auto-oxidation,8 the former contained only very small amounts of peroxidic oxygen (about 1% of the total oxygen).It was partly decomposed by water or strong acidic solutions with formation of carbon dioxide and hydrogen fluoride.(PDF) Biodegradability of Plastics sarang wazarkar Polymers are degraded into low molecular weight oligomers,dimers and monomers and finally mineralized to CO 2 and H 2 O.The clear zone method with agar plates is a widely used technique for screening polymer degraders and for assessment of the degradation potential of different microorganisms towards a polymer.
litwinienko autooxidation of unsaturated fatty acids 645 Fig.3 Temperatures of onset point,maximum 1 and maximum 2 for substances of dif- ferent initial peroxide number.a corn oil,b results for this questionWhat is polymeric oxidation?What is polymeric oxidation?Virtually all polymeric materials undergo oxidation reactions.Oxidation can occur at every stage of the life cycle of a polymer,i.e.during manufacturing and storage of the material or during processing and end-use.Typical manifestations of oxidation of polymers can be change of viscosity during processing,BASF Antioxidant results for this questionWhat happens to polymeric when it undergoes oxidation?What happens to polymeric when it undergoes oxidation?Virtually all polymeric materials undergo oxidation reactions.Oxidation can occur at every stage of the life cycle of a polymer,i.e.during manufacturing and storage of the material or during processing and end-use.BASF Antioxidant
results for this questionHow do antioxidants protect polymers against oxidation?How do antioxidants protect polymers against oxidation?Antioxidants protect polymers against oxidation by controlling molecular weight changes that lead to a loss of physical,mechanical and optical properties.2.1 Mechanisms Autooxidation of Polymersgt; Oxidation Organic materials react with molecular oxygen in a process called autoxidation.BASF Antioxidant results for this questionFeedbackRevising the mechanism of polymer autooxidation -
The basic scheme for autooxidation of polymers,originally developed by Bolland,Gee and co-workers for rubbers and lipids,is now widely applied to all types of polymeric materials.According to their scheme,the reaction that makes this process autocatalytic,referred to as the propagation step,is a hydrogen abstraction from the next substrate by the peroxyl radical Aging of Polymers,Polymer Blends and Polymer Contents Preface; IX Conference on Degradation and Stabilisation of Polymers; Multi-Component Photoinitiating Systems in Solid Polymers Mechanisms of Mutual Enhancement and Kinetic Models; Achievements and Research Tasks for Poly(vinylchloride) Ageing and Stabilisation; Heterogeneous Peculiarities of Polymeric Hydrocarbons' Autooxidation; Exitonik Processes of Polymer
Contents Preface; IX Conference on Degradation and Stabilisation of Polymers; Multi-Component Photoinitiating Systems in Solid Polymers Mechanisms of Mutual Enhancement and Kinetic Models; Achievements and Research Tasks for Poly(vinylchloride) Ageing and Stabilisation; Heterogeneous Peculiarities of Polymeric Hydrocarbons' Autooxidation; Exitonik Processes of Polymer
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