简介:伍德composites能通常在三部分被分类:把压成薄片的composites,混合composites和渗透的composites。每部分有它的自己的特征和罐头进一步被划分。这篇论文在中国介绍历史和木头composites的开发的国家。关于把胶水压成薄片的木材的研究是稀罕的,工业几乎不来到是。成就的一个伟人在混合composites被获得了,它是很好工业化的。scrimber上的许多研究被做了,中国研究人员正在寻找在中国开发scrimber工业的一个可行方法。中国研究人员也在学习木头塑料composites(世界和平理事会)花了那么多精力,但是它一直不由于高费用是工业化的。
简介:TwogradesofDyneema~?compositelaminateswiththecommercialdesignationsofHB26andHB50werecutintoblockswithorwithoutanedgecrackandcompressedinthelongitudinalfiberdirection.Thecrackedanduncrackedspecimensshowsimilarcompressiveresponsesincludingfailurepatternandfailureload.ThetwogradesofDyneema~?compositesexhibitsdifferentfailuremodes:adiffuse,sinusoidalbucklingpatternforDyneema~?HB50duetoitsweakmatrixconstituentandakinkbandforDyneema~?HB26duetoitsrelativelystrongermatrixconstituent.AneffectivefiniteelementmodelisusedtosimulatethecollapseofDyneema~?composites,andthesensitivityoflaminatecompressiveresponsestotheoveralleffectiveshearmodulus,interlaminarshearstrength,thicknessandimperfectionangleareinvestigated.Thechangeoffailuremodefromkinkbandtosinusoidalbucklingpatternbydecreasingtheinterlaminarshearstrengthisvalidatedbythefiniteelementanalyses.
简介:Collagenisthemajoracellcarofconnectivetissueproteininanimals,accountingforabout25%ofthetotalbodyproteinofvertebrates.Anessentialfeatureofthistypeofbiomaterialisthatitdegradesinbiologicenvironments,eventuallydisap-pears,andleavesnopermanentforeignresidue.Averypracticalaspectoftheuseofcollagenisitseaseofpreparationanditswidespreadoccurrenceinnature.Thus,col-lagenhasbeenemployedasabiomaterialinalmosteveryphysicalform.Forexam-ple,collagenfibrescanbeusedasasubstratefornerveregeneration,tendonligament
简介:Weinvestigatehigh-modulusdegradablematerialsintendedtoreplacemetalsinbiomedicalapplications.Thesearetypicallycompositescomprisingapolylactide(PLA)matrixreinforcedwithphosphateglassfibres,whichprovidereinforcementsimilartoE-glassbutareentirelydegradableinwatertoproduce,principally,calciumphosphate.Wehavemadecompositesusingavarietyoffibrearchitectures,fromnon-wovenrandommatstounidirectionalfibretapes.Flexuralpropertiesintheregionof30GPamodulusand350MPastrengthhavebeenachieved-directlycomparabletoquotedvaluesforhumancorticalbone.Incollaborationwithothergroupswehavebeguntoconsiderthedevelopmentoffoamedsystemswithstructuresmimickingcancellousboneandthishasshownsignificantpromise.Thefibresinthesefoamedstructuresprovideimprovedcreepresistanceandreinforcementoftheporewalls.Todatethematerialshaveexhibitedexcellentcellularresponsesinvitroandfurtherstudiesareduetoincludeconsiderationofthesurfacecharacterofthematerialsandtheinfluenceofthisoncellinteraction,bothwiththecompositesandtheglassfibresthemselves,whichshowpromiseasastandaloneporousscaffold.
简介:Inthispapertheresultsofahigh-speedtensionexperimentoftheSiC_w/Alcompositehavebeenreportedandasimplifiedtheoreticalmodelhasbeendevelopedtostudythefracturemechanismofcompositesinhigh-speedtension.Thistheoreticalmodelprovidesanewexplanationfortheincreaseofdynamicfracturestrengthofcompositesinhigh-speedtension.
简介:Thedynamicmechanicalpropertiesofwoodpowder/polypropylenecompositeswithdifferentwoodcontenttreatedanduntreatedwiththecompatibilizerhavebeenstudied.Ithasbeenfoundthatadditionofwoodpowdersandthecompatibilizercanbothimprovetheviscoelasticityofcomposites.Glasstransitiontemperature(Tg)ofappropriatewoodpowder-filledcompositesdecreased.Thevalueforthestoragemodulus(G')increasedgraduallywithincreasingwoodpowdercontent.Theadditionofthecompatibiliz...
简介:ThefracturebehaviorofSiCp/A356compositeatroomandhightemperatureswasstudied.Undertensilestressconditionatroomtemperature,thefractureismostlyacombinationofthebrittlefractureofSiCparticlesandductilefractureofA356matrix.Asthetensiletemperatureincreases,thecompositechangesthemainfracturebehaviortotheseparationfractureofthebondingsurfacebetweenSiCparticlesandA356matrix.Whenthetensiletemperaturereaches573K,thefracturebehaviorofthecompositesisalmostthewholeseparationfractureofthebondingsurface,whichisthemainstrengtheningmechanismathightemperature.Underthecyclestressconditionatroomandhightemperatures,themainfracturebehaviorofthecompositesisalwaysacombinationofthebrittlefractureofSiCparticlesandductilefractureofA356matrix.However,underthecyclestressathightemperature,cyclebehaviorofthecompositeschangesfromcyclehardeningatroomtemperaturetothecyclesofteningathightemperature.
简介:Flammabilitypropertiesofcompositesofwoodfiberandrecycledplasticwereevaluatedbytheconecalorimeterandoxygenindexchamber.Resultswereshownasfollows:1)Wood-PVCcompositeshowedworsethermalstabilityontimetoignition(TTI)andmeanheatreleaserate(MHRR),butbetterperformanceonheatreleaserate(HRR)andmeanefficientheatofcombustion(MEHC);wood-PPcompositehadbetterthermalstabilityproperties,butwasworseonotherfireperformance;2)Comparedwithwood-PVCcomposi...
简介:竹子powder/polycaprolactonecomposites(BPPC)被转矩电流计准备调查配方的效果,处理在变阻器上调节BPPC的逻辑性质。词法行为和BPPC的机械性质也被学习。结果证明合成材料的最佳配方由70%polycaprolactone组成,30%竹子根据体积搽粉,联合代理人的铝酸盐的1.6%,1.2%硬脂的酸,和到竹子的2%石蜡根据质量搽粉比率。处理条件参数的最佳为BPPC在100°C在−1和温度在50r·m作为旋转速度被决定。BPPC(包含30拷贝竹子粉末)拥有的著名界面的相容性和BPPC的机械性质。
简介:Agroupofpoly(phthalazinoneethersulfoneketone)/potassium-titanate-whisker(PPSEK/whisker)compositeswaspreparedbycoprecipitationfromsolution.Thewhiskersurfacewasmodifiedusingtitanatecouplingagentpriortoblending.Thetensile,impact,morphologyandthermalpropertiesofthemouldedcompositeswereinvestigated.Themeasurementsshowedthatthetensilestrengthandimpactstrengthofthecompositesincreasedwithincreasingwhiskerscontentupto10to20phr,thereaftertheyshowedadecreaseinthewhiskerscontentreached40phr.Atthesametime,themodulusofthecompositesincreasedwithincreasingwhiskerscontent.Scanningelectronmicroscopystudiesrevealedthatthewhiskerswithinthecompositesweredisperseduniformlybytreatedwithcouplingagent.Finally,thermogravimetricanalysisshowedthattheheatresistanceofthecompositestendedtoincreasewithincreasingwhiskercontent.Theresultswereanalysedanddiscussedintermsofestablishedmodelsofthebehaviourofshort-fiberreinforcedcomposites.
简介:Inordertoimprovethemechanicalpropertiesofpolypyrrole,compositesweremadebyelectropolymerizingpolypyrroleinapolyurethanematrix.Polypyrrole/polyurethane(PPY/PU)compositefilmscontainingCLO4-,BF4-orCH3-C6H4-SO3-counterionsweremadeinavarietyofsolventsystemsandcharacterizedbySEM,electronicconductivity,FTIR,andmechanicalproperties.Compositefilmsshowingmuchgreaterfiexibilitythanpurepolypyrrolewereobtained,buttheirelectronicconductivitiesweresubstantiallylower.Measuredeonductivitiesrangedfrom0.001to8S/cm,tensilestrengthsfrom44to592psi,andelongationtofailurefrom3to70%.
简介:Ion-exchangePolymerMetalComposites(IPMC)areanewclassofintelligentmaterialthatcanbeusedeffectivelyasactuatorsandartificialmuscles.IPMCwasfabricatedanditsdisplacementandforcecharacteristicswereinvestigatedwithrespecttovoltage,frequencyandwaveformofthecontrollingsignal.Asquarewaveforminputgeneratedslightlylargerdis-placementandforcethansinusoidalortriangularwaveform.Whenthevoltagewasincreasedandthefrequencywasdecreased,displacementandforcewerebothincreased.However,althoughthebendingdeformationofIPMCwaslarge,theoutputforcewasmuchlowerthanweexpected.ImprovementoftheforceoutputiskeyandisthemainobstacletobeovercomeinordertomakeIPMCofpracticaluse.
简介:Thioglycolicacid(TGA)-stabilizedCdTenanocrystals(NCs)werepreparedwithsodiumtelluriteastelluriumsource,whichavoidsthecumbersomeprocessesassociatedwithH2TeorNaHTesources.FluorescentCdTe/SiO2compositesweresynthesizedbyasol-gelmethodwithouttheexchangeofsurfaceligands.ThephasestructureofCdTeNCswasinvestigatedbyX-raydiffractometry.Forcomparison,somecharacterizationsweredoneforboththeCdTeNCsandthecomposites.CdTeNCsandCdTe/SiO2compositeswerecharacterizedwithTEM,digitalcameraandfluorescencespectrophotometer.ThestabilityofCdTeNCsandthecompositeswereinvestigatedinphosphate-bufferedsaline(PBS)bufferandthefluorescentpropertiesofthecompositeswerediscussedindetail.
简介:Someoftheprogressmadeinourlaboratoriesincollaborationwithindustryinresearchanddevelopmentworkonhighperformanceoxide-nonoxidecompositesformetallurgicalapplicationshasbeenreviewed.(1)SiAlONbondedcorundumcompositesforblastfurnaceusagehavebeenproducedbyreduction-nitridationsinteringathightemperature,usingbauxiteinsteadofaluminainthematrix.(2)LowcarbonAl2O3-SiAlONslideplatematerialssuccessfullyusedinhighqualitysteelcontinuouscastinghavebeendevelopedinwhichmostorallofthegraphiteinAl2O3-Cbrickisreplacedbybauxite-basedβ-SiAlON.(3)Al/SimetalbondedAl2O3-Cmaterialcharacterizedbylowcarboncontent,lowfiringtemperatureandin-situformationofcarbidesandnitridesathightemperatureduringservicearefoundtopossessveryhighhotstrengthandverygoodthermalshockresistanceandhavealsobeensuccessfullyusedasslideplatesinladlesandtundishesforhighqualitysteelcasting.