英语科技论文写作ppt课件

.,1,By,FeiMingyue,Functionalpackagingmaterials:factorsaffectingthecapacityandrateofwateradsorptionindesiccantcomposites,.,2,1,2,3,4,Introduction,Experimental,Resultsanddiscussion,Conclusions,5,Acknowledgments,Content,.,3,Plasticpackagingmaterialsformanimportantpartoftheeconomyandoureverydaylife.Theyfulfillnumerousfunctions,suchasmakingitpossibletosafelydistributeproducts,protectingthemfromtheenvironment,andinformingthecustomer.,Introduction,However,theever-increasingdemandsofconsumershaveresultedinnewpackagingsolutions,includingfunctionalandsmartpackagingmaterials.Thelatterrespondtochangesintheenvironment,whiletheformerfulfillssomefunctionthatimprovestheperformanceofthepackaging.Thenumberofthesematerialsisincreasingrapidly,andtheyarealreadyusedineverydaylife.,.,4,Introduction,Themainfunctionstargetedforfunctionalpackagingmaterialsarehumiditycontrol,regulatingethylenecontent,exertinganantimicrobialeffect,adsorbingodorousmaterials,ortheoppositereleasingdesirablearomas.Controllingthehumidityofpackagedwaresisextremelyimportantinseveralareas.,.,5,Forseveralhundredyears,thequalityoffoodhasbeenpreservedbydryingitout,butmoisturecontrolhasrecentlybecomeveryimportantinthepharmaceuticalandelectronicindustriesaswell.Controllingmoisturecontentisimportantinfoodpackaging,whilemaintainingdryconditionsisusuallyarequirementofpackagingforpharmaceuticalsandelectronics.,Introduction,Sothedesiccantcanbeaddedtothepackagedwareinasemipermeablesatchetorincorporatedintothepackagingmaterial.,.,6,Introduction,Asaconsequence,thegoalofourstudywastocarryoutsystematicexperimentswithdesiccantcompositespreparedwithaselectedzeoliteandtodeterminetheeffectofdesiccantcontentandthepropertiesofthematrixpolymerontherateandcapacityofwateradsorption.Threedifferentpolymerswereselectedforthestudy,anddesiccantcontentwasvariedacrossawiderangefrom0to50vol.%.,.,7,PolymershighdensitypolyethylenepolycarbonatepolyvinylchloridepolymerDesiccant5A-typezeoliteTheaverageparticlesizeofthedesiccantwas4.5m,itsdensitywas1.66g/cm3,anditsspecificsurfaceareawas533g/m2.Thetheoreticalporediameterofthiszeolitewas4.3.,Experimental,.,8,Beforecompositepreparation,thezeolitewasdriedat300Cfor16hinavacuum.ThecomponentswerehomogenizedinaBrabender(Duisburg,Germany)W50EHinternalmixerattachedtoaHaake(ThermoScientific,Waltham,MA,USA)RheocordEU10Vdrivingunitat190Cfor10min,exceptforPC,forwhichthemixingwasdoneat240C.,Experimental,.,9,Experimental,One-millimeter-thickfilmswerecompressionmoldedfromthehomogenizedmaterialat190or240C.Thezeolitecontentsofthecompositesvariedbetween0and50vol.%.Thewateradsorptionsofthezeoliteandthecompositesweredeterminedbymeasuringtheweightsof20201mmspecimensunderanatmosphereof100%RHasafunctionoftime.,.,10,Resultsanddiscussion,Adsorptionisrelativelyfast,andthedesiccantadsorbs23.8%ofitsweightinwater.,.,11,Resultsanddiscussion,Wecanseethemuchslowerrateofadsorptionmentionedabove,andalsothatmaximumadsorptionismoreorlessproportionaltothezeolitecontentofthecomposite.,.,12,Resultsanddiscussion,3,Comparisonoftheresultsobtainedforthethreepolymersshowsthattheadsorptioncapacityofthecompositedependsmainlyontheamountofdesiccantpresentandonlyslightlyonthetypeofthepolymerusedasthematrix.,.,13,Resultsanddiscussion,3,Accordingtothefigure,adsorptionincreaseswithzeolitecontentlinearlyforallthreepolymers,anditiscompletelyindependentofthetypeofpolymerusedasthematrix.,Fig.4Effectsofmatrixtypeandzeolitecontentonthewateradsorptioncapacitiesofdesiccantcomposites.(squaresHDPE,cirlclesPVC,trianglesPC),.,14,Thisstudyofzeolitedesiccantcompositespreparedwiththreedifferentmatricesshowedthatthedesiccantcanadsorbaconsiderableamountofwaterinitsfreepores.Theadsorptioncapacityofthecompositedependslinearlyontheamountofdesiccantpresent,butisindepende