Introduction to Silicones: Properties, Types, and Applications
Silicones are versatile materials with a range of properties making them essential in various industries. From silicone fluids to resins, they find applications in rubber production, high-speed bearings, electrical insulation, and more. The preparation involves the reaction of methyl chlorides with silicon, resulting in different types of methyl-substituted chlorosilanes. Silicones exhibit low thermal conductivity, chemical reactivity, and toxicity, yet offer water repellency, UV resistance, and electrical conductivity. Their applications span from computer components to solar panels, showcasing their importance in modern technology and everyday life.
Download Presentation
Please find below an Image/Link to download the presentation.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author. If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.
You are allowed to download the files provided on this website for personal or commercial use, subject to the condition that they are used lawfully. All files are the property of their respective owners.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.
E N D
Presentation Transcript
SILICONES INTRODUCTION
INTRODUCTION OFSLICONES SILICON ISA CHEMICALELEMENTWITH THESYMBOL SI ANDATOMIC NUMBER14. ITISA HARD,BRITTLECRYSTALLINESOLIDWITH A BLUE-GREY METALLICLUSTER,ANDISA TETRAVALENTMETALLOIDANDSEMICONDUCTOR. ITISA MEMBEROF GROUP14 IN THE PERIODICTABLE:CARBONISABOVEIT;ANDGERMANIUM,TIN,LEAD,AND FLEROVIUMARE BELOWIT.
TYPESOFSILICONES 1. SILICONEFLUIDS:SILICONESOILSAREHAVINGLOW TEMPERATURESCOEFFICIENTOFTHE VISCOSITY.ALSOUSEDASINSULATINGMATERIALANDANTIFORMINGAGENTS 2. SILICONER UBBE R S:SILICONEOILSCAN BEMIXE DWITHLITHIUM SOAPSTO GIVEGR E ASE S.IT ISUSEDASBALLBEARINGATHIGHSPEEDSATAND HIGHTEMPERATURE. 3. SILICONEGREASES:THESEARELONGSTRAIGHTCHAIN POLYMERS WITHHIGHMOLECULAR WEIGHT.THESEAREUSEDASGOODELECTRICALINSULATORS 4. SILICONESRESINS:THESEARERIGIDCROSSLINKEDPOLYMERSOFMANYTYPESSUCHAS ELECTRICALRESINS.THESEAREUSEDASPAINTSAND VARNISHES.
P R E P ARATION OFSILICONEPLOYMERS WHENMETHYLCHLORIDEREACTSWITH SILICON IN THEPRESENCEOF COPPERASA CATALYST ATA TEMPERATURE570 K, VARIOUSTYPESOF METHYLSUBSTITUTEDCHLOROSILANES ARE FORMED. HYDROLYSIS OFDIMETHYLDICHLORO SILANEI. E.,(CH3)2SICL2FOLLOWED BY CONDENSATIONPOLYMERISATIONFORMSSTRAIGHTCHAIN.
PROPERTIE SOFSILICONES SOMEOFTHECOMMON PROPERTIESOF SILICONESAREASFOLLOWS; SILICONESHAVELOW THERMALCONDUCTIVITY ANDCHEMICALREACTIVITY. THE IRTOXICITYISALSO LOW. ITCAN RE PE LWATE RAND FORM WATE RTIGHTSE ALS. HASHIGH RESISTANCETOOXYGEN, OZONE, AND ULTRAVIOLET(UV) LIGHT. HASBOTHELECTRICALLYINSULATIVEAND CONDUCTIVE PROPERTIES. HIGH GASPERMEABILITYAND HIGHTHERMALSTABILITY SUPE RIORSOL VE NTS FORORGANIC COMPOUNDS..
APPLICATION OFSILICONES SILICONES CANACQUIREMANY FORMS FROM LIQUIDSTOSOLIDSTHATALLOWENGINEERS, INVENTORS, ANDCOMPANIES TOUSETHEMASA KEYCOMPONENT IN VARIOUS INDUSTRIAL APPLICATIONS. ITISTHEIRVERSATILEQUALITYTHATMAKES SILICONESAN ESSENTIAL INGREDIENT IN PRODUCTS THATMAKEOURLIVESBETTER,WHETHERASRUBBERS,FLUIDS, RESINS,SILICONEGELSORSILICONGLUE.SILICONESCANBEFOUNDIN A DIFFERENTNUMBER OFAPPLICATIONSSTARTINGFROMCOMPUTERSAND ENGINEEREDSPACECRAFT,SHAMPOO TOBAKINGMOULDS.SILICONESCANALSOBECONSUMEDIN RENEWABLEENERGYSTARTING FROMWIND TURBINESTOSOLARPANELSRELYONSILICONETECHNOLOGY..
DIRECTSILICONEPROCESS 2. DIRE CTPROCE SS IN THISPROCESS,SIRECTLYREACTWITH ALKYLHALIDETOGETCHR CATAL YSTUSE D: CUTUBE TE MPE RATURE250-280 C SI + RXR.SI XI ADVANTAGE MOREECONOMICAL AND LESSSTEPSINVOLVE - DISADVANTAGE HIGHER ALKYLHALIDE DECOMPOSE ATREACTIONTEMPERATUREANDGIVE POOR YIELDOF DESIREDPRODUCT
GRIGNARDMETHOD 1. GRIGNARD METHODGRIGNARD COMPOUNDS AREPOPULARREAGENTSIN ORGANIC SYNTHESIS FORCREATING NEWCARBON-CARBON BONDS. FOREXAMPLE,WHEN REACTED WITH ANOTHERHALOGENATED COMPOUND R X IN THEPRESENCEOF ASUITABLECATALYST, THEYTYPICALLYYIELDR R ANDTHEMAGNESIUM HALIDEMGXX ASABYPRODUCT; AND THE LATTERIS INSOLUBLEIN THESOLVENTSNORMALLYUSED.IN THISASPECT,THEYARESIMILAR TO OR GANOLITHIUMR E AGE NTS.
AROMATICSILIATION BENZENEISREACTWITHDICHLORO SILIANEIN PRENSENCEOFBH3 AT250DEGREE FROM DIPHENYLDICHLOROSILANECHLORO SILIANEITISON HYDROLOSIS WITH WATERGIVES SILICONES.20 SILYLATION INVOLVESTHEREPLACEMENTOF ANACIDICHYDROGEN (ORAN ACTIVEHYDROGEN) ON THECOMPOUND WITH ANALKYLSILYLGROUP. HENCE,SILYLATION DERIVATIZATION ACHIEVESCOMPOUNDS THATAREGENERALLYLESSPOLAR,MORE VOLATILE, ANDHAVEINCR E ASE DTHE R MALSTABILITY..
REFERENCESOFSILICONES REFERENCES CHEMISTRYOF THEELEMENTSN.N.GREENWOOD AND A.EARNSHAW, II EDITION (1997). CONCISE INORGANIC CHEMISTRY-J.D.LEE,VEDTITION (1996). INORGANICCHEMISTRYKEITHF.PURCELL,JOHN.C.KOTZ.INDIANEDITION,CENGAGELEARNING PUBLICATION. INORGANIC CHEMISTRY,PRINCIPLESOFSTRUCTUREAND REACTIVITY.JAMESE.HUHEEY,ELLEN A.KEITER,RICHARDL.KEITER,OKHILK.MEDHI,IV EDITION,PEARSONPUBLICATION POLYMERSCIENCE-V.R.GOWARIKER, N.VVISWANATHAN, JAYADEVSREEDHAR,ILEDITION, NEW AGEINTERNATIONAL(P) LIMITED PUBLISHERS.
