资源描述：
《Dynamic mechanical and morphological studies of isotactic polypropylene_fumed silica nanocomposites with enhanced gas barrier properties.pdf》由会员上传分享，免费在线阅读，更多相关内容在应用文档-天天文库。
1、COMPOSITESSCIENCEANDTECHNOLOGYCompositesScienceandTechnology66(2006)2935–2944www.elsevier.com/locate/compscitechDynamicmechanicalandmorphologicalstudiesofisotacticpolypropylene/fumedsilicananocompositeswithenhancedgasbarrierpropertiesaabbb,*V.Vladimirov,C.Betchev,A.Vassiliou,G.Papageor
2、giou,D.BikiarisaCentralScientificandResearchLaboratory,UniversityofChemicalTechnologyandMetallurgy,8,KlimentOhridskiBlvd.,1756Sofia,BulgariabLaboratoryofOrganicChemicalTechnology,DepartmentofChemistry,AristotleUniversityofThessaloniki,GR-54124Thessaloniki,Macedonia,GreeceReceived11Januar
3、y2006;receivedinrevisedform7February2006;accepted12February2006Availableonline31March2006AbstractPolypropylene/fumedsilicananocompositeswerepreparedviameltmixingusingatwin-screwco-rotatingextruder.Toimprovethedispersiondegreeofthenanoparticles,maleicanhydridegraftedpolypropylene(PP-g-M
4、A)wasusedasacompatibilizer.Fromtransmis-sionelectronmicroscopyitwasfoundthatagglomerationsofsilicaparticlesintothePPmatrixincreasedinaveragesizewithincreasingsilicacontentswhilsttheydecreasedathigherPP-g-MAamounts.StoragemodulusvaluesofpreparednanocompositesmeasuredbyDMTAweresensitivet
5、othemicrostructureofthenanocomposites.Highersilicacontentsresultedinhigherstoragemodulus,evidencerevealingthatthematerialbecamestiffer.ByaddingthePP-g-MAcopolymerafurtherincreaseofstoragemoduluswasobservedduetothefinerdispersionofthefillerinthematrixandtheincreasedinterfacialadhesion.Both
6、permittedamuchmoreefficienttransferofstressesfromthepolymermatrixtotheSiO2nanoparticles.CrystallizationrateswerefoundtoincreasebyincreasingsilicananoparticlesaswellasPP-g-MAcontent.InfactforagivenPP-g-MAcontentincreasingthesilicacontentupto5–7.5wt%acceleratedthecrystal-lization.Furtherin
7、creaseofthenanoparticlesamountdidnothaveanyeffect.PermeabilityratesofO2andN2throughfilmsofiPP/SiO2werealsomeasured.LowerrateswereobservedcomparedtopureiPP,mostnotablyforO2,whichdecreasedwithincreasingconcen-trationsofsilica.Thiswasattributedtothemoretortuouspathwhichmustbecoveredbytheg
