Resin Matrix Composite

Introduction

Thecommonlyusedresinsforfiberreinforcedresinmatrixcompositesareepoxyresinandunsaturatedpolyesterresin.Commonlyusedare:thermosettingresins,thermoplasticresins,andvariousmodifiedorblendedbases.Thethermoplasticresincanbedissolvedinasolvent,oritcansoftenandmeltintoaviscousliquidwhenheated,andthenbecomehardaftercooling.Thermosettingresinscanonlybeheatedandmoldedonce,andsolidifyduringprocessingtoforminfusibleandinsolublenetworkcross-linkedpolymercompounds,sotheycannotberegenerated.Theresinmatrixofthecompositematerialismainlythermosettingresin.Asearlyasthe1940s,glassfiberreinforcedplasticswereusedasradomesonfightersandbombers.Inthe1960s,theUnitedStatesusedboronfiber-reinforcedepoxyresinasrudders,horizontalstabilizers,rearedgesofwings,rudderdoors,etc.onmilitaryaircraftsuchasF-4andF-111.Intermsofmissilemanufacturing,inthelate1950s,thesecond-stagesolidrocketmotorshelloftheAmericanmedium-rangesubmarinemissile"PolarisA-2"usedglassfiber-reinforcedepoxywindingparts,whichwerelighterthansteelshells.%;Later,high-performanceglassfiberwasusedinsteadofordinaryglassfibertomakethe"PolarisA-3",whichmadetheshellweight50%lighterthanthesteelshell,sothattherangeofthe"PolarisA-3"missilewasincreasedfrom2700kilometers.To4500kilometers.Afterthe1970s,theuseofaromaticpolyamidefiberinsteadofglassfiberreinforcedepoxyresingreatlyimprovedthestrengthandreducedweight.Carbonfiber-reinforcedepoxyresincompositematerialshavebeenwidelyusedinstructuressuchasaircraft,missiles,andsatellites.

Application

Epoxyvinylesterresinhasagoodapplicationinthechlor-alkaliindustry.

Thechlor-alkaliindustryisoneoftheearliestapplicationfieldsofFRPasacorrosion-resistantmaterial.Atpresent,FRPhasbecomethemainmaterialofthechlor-alkaliindustry.FRPhasbeenusedinvariouspipingsystems,gasblowers,heatexchangershells,brinetanks,pumps,pools,floors,wallpanels,grilles,handles,railingsandotherbuildingstructures.Atthesametime,FRPhasalsobeguntoentervariousfieldsofthechemicalindustry.Theapplicationinthepaperindustryisalsodeveloping.Thepaperindustryuseswoodasrawmaterial.Thepapermakingprocessrequiresacids,salts,bleachingagents,etc.,whichhaveastrongcorrosiveeffectonmetals.OnlyFRPmaterialscanwithstandsuchharshenvironments.Thematerialhasshownitsexcellentcorrosionresistanceinpulpproductioninsomecountries.

Theapplicationinthemetalsurfacetreatmentindustryhasbecomeanimportantapplicationofepoxyvinylesterresin.Theacidusedinmetalsurfacetreatmentplantsismostlyhydrochloricacid.Basically,itisnoproblemtouseFRP.Epoxyresinentersthechemicalanticorrosionfieldasafiber-reinforcedcompositematerial,appearingintheformofepoxyvinylesterresin.ItismadeofbisphenolAepoxyresinandmethacrylicacidthrougharing-openingadditionchemicalreaction.Theproportionofepoxyresinrequiredpertonisupto50%.Thistypeofresinnotonlyretainsthebasicpropertiesofepoxyresin,butalsohasdisadvantages.Saturatedpolyesterresinhasgoodprocessperformance,soitiswidelyusedinthefieldofchemicalanti-corrosion.

Itsanti-corrosioninthechemicalindustrymainlyincludes:chemicalpipelines,storagetanklinings;electrolyzers;floors;electricmisteliminatorsandexhaustgasdesulfurizationdevices;offshoreplatformderricks;anti-corrosionmoldedgrilles;Valves,three-wayconnectors,etc.Inordertoimprovethesuperiorheatresistance,corrosionresistanceandstructuralstrengthofepoxyvinylesterresin,theresinhasbeencontinuouslymodified,suchasphenolic,brominated,toughenedandotherepoxyvinylesterresins,whicharewidelyusedinlarge-scaleapplications.Diameterwindblades,magneticlevitationrailreinforcementnets,racinghelmets,opticalfibertowbars,etc.

Stiffness

Thestiffnesscharacteristicsofresinmatrixcompositesaredeterminedbythepropertiesofthecomponentmaterials,theorientationofthereinforcingmaterialsandthevolumefractionoccupied.Themechanicalstudyofresin-basedcompositematerialsshowsthatforamacro-uniformresin-basedcompositematerial,thecompositeofelasticpropertiesisamixingeffect,manifestedinvariousformsofmixinglaw,whichistheaverageoftherigidityofthecomponentmaterialsinacertainsense.Theeffectofinterfacedefectsonitisnotobvious.

Duetotheinfluenceofmanufacturingprocessandrandomfactors,thereareinevitablyvariousinhomogeneitiesanddiscontinuitiesinactualcompositematerials.Residualstress,voids,cracks,imperfectinterfacebonding,etc.willaffectTheelasticpropertiesofthematerial.Inaddition,theshape,regularity,anduniformityofthefiber(particle)willalsoaffecttheelasticpropertiesofthematerial.Butingeneral,thestiffnessofresin-basedcompositesisamacroscopicreflectionofthestabilityofphasematerials.   

Forthelaminatedstructureofresin-basedcompositematerials,couplingdeformationcanoccurbasedonthedifferentmaterialsandpropertiesofthesinglelayerandthedirectionofthelayer,whichmakesthestiffnessanalysiscomplicated.Ontheotherhand,itisalsopossibletodesignthestiffnessofthelaminatedstructurebydesigningtheelasticconstants(includingelasticmodulusandPoisson'sratio)ofthesinglelayer,andthenselectingthedirection,numberandorderofthelayeringtodesigntherigidityofthelaminatedstructuretoadapttotheapplicationofdifferentoccasions.Require.  

Strength

Thestrengthofthematerialisfirstlinkedtothefailure.Thedestructionofresinmatrixcompositesisadynamicprocess,andthefailuremodeiscomplex.Themechanismofactionofeachcomponent'sperformanceondamageandtheinfluenceofvariousdefectsonstrengthhavebeenstudiedindetail.   

Thecombinationofthestrengthoftheresinmatrixcompositeisasynergisticeffect.Thestrengthpropertiesarederivedfromtheperformanceofthecomponentmaterialsandthemicrostructureoftheresinmatrixcompositeitself.Forthesimplestcase,themesomechanicalresearchonthestrengthandfailureofunidirectionalresinmatrixcompositesisnotmatureenough. 

Theaxialtensileandcompressivestrengthsofunidirectionalresinmatrixcompositesaredifferent,andtheaxialcompressionproblemismorecomplicatedthanthestretchingproblem.Itsfailuremechanismisalsodifferentfromstretching,itisaccompaniedbylocalbucklingofthefiberinthematrix.Experimentshaveshownthatunderaxialcompressionofunidirectionalresin-basedcomposites,carbonfibersareshearedanddamaged;Kevlarfibershaveakinkingmode;andglassfibersaregenerallybentanddamaged. 

Thetransversetensilestrengthandcompressivestrengthofunidirectionalresinmatrixcompositesarealsodifferent.Experimentsshowthatthetransversecompressivestrengthis4to7timesthetransversetensilestrength.Thefailuremodeoftransversetensionismatrixandinterfacefailure,andmayalsobeaccompaniedbytransversefibercracking;transversecompressionfailureiscausedbymatrixfailure,whichisgenerallyshearedalonga45°inclinedplane,sometimesaccompaniedbyinterfacefailureandfibercrushing.Thein-planeshearfailureofunidirectionalresinmatrixcompositesiscausedbytheshearofthematrixandtheinterface.Theestimationofthesestrengthvalues​​dependsonexperiments.

Althoughmessyshortfiberreinforcedresinmatrixcompositesdonothavethehighstrengthofunidirectionalresinmatrixcompositesintheaxialdirection,theyaremuchbetterthanunidirectionalresinmatrixcompositesintermsoftransversetensileandcompressiveproperties.,Hasitsowncharacteristicsintermsoffailuremechanism:thewovenfiberreinforcedresinmatrixcompositematerialcanbeapproximatedasatwo-layerlaminatedmaterialinmechanicaltreatment,butthemicroscopicmechanismoffatigue,damage,andfailureismorecomplicated. 

Thesynergisticeffectofthestrengthpropertiesofresinmatrixcompositesisalsomanifestedinthelaminationeffectoflaminatedmaterialsandthehybrideffectofhybridcomposites.Inthelaminatedstructure,thepotentialstrengthofasinglelayerisdifferentfromthestrengthofasingleforce.Forexample,thetransversestrengthofthe90°layerobtainedbythe0/90/0laminatestretchingisthetransversetensilestrengthofthesinglelayerobtainedbytheindividualexperiment.2to3times;thesameistrueforthein-planeshearstrength,thisphenomenoniscalledthelaminationeffect.

Thecomplexityofthestrengthproblemofresinmatrixcompositescomesfromthepossibleanisotropyandirregulardistribution,suchastheusualenvironmentaleffects,butalsofromthedifferentfailuremodesmentionedabove,andthesamematerialisindifferentUnderdifferentconditionsanddifferentenvironments,thefracturemayproceedindifferentways.Theseincludechangesinthestructureofthematrixandfibers(particles),suchaseffectscausedbylocalweakpoints,cavities,andstressconcentrations.Inaddition,thenatureandstrengthoftheinterfacebond,thedensityoftheaccumulation,thelapofthefiber,thestressconcentrationatthefiberend,theinterferenceofcrackgrowth,andthedifferencebetweenplasticandelasticresponsehaveacertainimpact.