Tensiledeformationandfracturecharacteristicsofpolyimide/montmorillonitenanocompositefilmsareinvestigatedtoenhancetheparticularmechanicalpropertiesandunderstandtheeffectivefactorsindominatingthemechanicalpropertiesofnanocomposites,suchasthenanolayer,matrixandnanolayer/matrixinterface.Howtocontributetothemechanicalpropertiesofnanocompositefilmisaverycomplexproblem.Inthispaper,thesefactorsareanalyzedbasedontheadditionamountandfracturemechanics.Theresultsindicatethatthespecimenat20wt%MMTbreaksprematurelywithafracturestrength(σb=78MPa)muchlowerthanthat(σb=128MPa)atthe1wt%MMT.However,theYoung'smodulus(3.2GPa)oftheformerishigherthanthat(1.9GPa)ofthelatter.Fractographyalsoindicatesthatthebrittlecrackingformedinhighcontentadditionisthemaincauseoffailurebutmicroscopicallyductilefracturemorphologystillexistslocally.Andforthetraceelementaddition,thesmallerthreadingslippingveinsareevenlydistributedontheentirefracturesectionofthesefilms.Therefore,thesecharacteristicswouldpresumablybeassociatedwithboththeconcentrationeffectsofsizeofnanocompositesheetsandtheincreasingdeformationharmonyinnanolayers.
