等规聚丙烯微注塑制品形态结构和力学性能

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1、ABSTRACTThepolymermeltundergoeshightemperature，highpressureandhighshearinthemicro-injectionmoldingprocess．Theflowbehaviorperformancesrheologicalphenomenawhichisdifferentfromthatofmacro-injectionmoldingsuchaswallslip，surfacetensionandsizedependenceofviscosity．ThemorphologyofiPP

2、productssuchasskin—corestructure，skinlayerthickness，orientation，Crystallinityandpcrystalcontentarestronglyinfluencedbythespecialrheologicalbehavior．Themechanicalpropertiesaredeterminedbythemorphologyofthemicro-injectionproducts．Therefore，ithasimportantmeaningtostudytherelation

3、shipbetweentheprocessingconditions，themorphologyandthemechanicalpropertiesofthemicroinjectionmolding．Themainworkandconclusionsareasfollows：1．TheInfluencelawandsignificanceoftheprocessparametersonthemorphologyofthemicro—injectionproducts．TheOrthogonalexperimentofsixfactorsandfi

4、velevelsWasselected，thesixfactorsweremelttemperature，moldtemperature，injectionspeed，packingpressure，packingtime，coolingtime．Thelayerthickness，orientation，Crystallinityandpcrystalcontentwerechoosedasindicatorsofmicroinjectionmoldingproducts．Influencelawandsignificanceoftheproce

5、ssparametersonthemorphologyofthemicro—injectionproductswerestudied．ThentheInfluencelawofscaleeffectonthemorphologyWasexplored．Theresultshowedthat：theimportanceandinfluenceofprocessparametersondifferentstructuralindicatorsweredifferentfromeachother．Asfor1．0mmand0．5millmicro—inj

6、ectionproducts，themostimportantfactoronskinlayerthicknessandorientationWasinjectionspeed．Withtheinjectionspeedincreasing，theskinlayerthicknessandorientationreduced．Theinfluenceofprocessparametersonthemorphologyisdifferentbecauseofscaleeffect．Asthethicknessdecreased，thepercenta

7、geofskinlayerthickness，orientationandpcrystalcontentincreasedbutCrystallinitydecreased．2．TheInfluencelawandsignificanceoftheprocessparametersonthemechanicalpropertiesofthemicro-injectionproducts．Yieldstress，modulusandIIIABSlKACI’elongationatbreal(wereselectedasmechanicalproper

8、tiesindexes．Influencelawandsignificanceoftheprocessparameters