等规聚丙烯微注塑制品结晶形态与制品收缩的研究

《等规聚丙烯微注塑制品结晶形态与制品收缩的研究》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、ABSTRACTWiththedevelopmentofscienceandtechnology,micro—electromechanicalsystems(MEMS)andmicro—systemstechnology(MST)havebeensuccessivelyappliedtomanyfields．Micro-injectionmolding(MIM)isoneofthemostimportantprocessesforreplicatingmicrostructuredpartsandmicrop

2、artswithhighprecision．Becauseoftheapplicationinhigh—grade，precisionandadvancedfieldsofmicroinjectionmoldedparts，thehigherpropertyofthepartsisdemand．Themorphologyofstructureplaysamajorroleinmasteringthefinalpropertiesoftheproducts，therefore，investigationofmor

3、phologyofthemicropartshasimportantsignificance．Inthiswork，theiPPmicropartswithtwodifferentthicknesswerechoseninthestudy．TheinfluenceofprocessingparametersonmorphologyandshrinkageoftwokindsofmicropartsWasinvestigatedbasedonthemicroinjectionmoldingexperiments。

4、Theworkincludes：1．Theinfluenceofscaleeffectonmorphologyofthemicroparts．Bymeansofpolarizedlightmicroscopy(PLM)andwideangleX—raydiffraction(WAXD)，themorphologyevolutionofmicropartswasinvestigated．PLMobservationsindicatedthatmorphologyalongthethicknessdirection

5、ofmicropartsexhibitedasimilarskin—corestructureasmorphologyofthetraditionalinjectionparts．Therearethreestructuresinthemicropartsincludingskinfrozenlayer,shearlayerandcorelayer,andshearlayerpresentedalargefractionofthethicknessinmicroinjectionmoldedparts．Thec

6、orelayerinthetraditionalinjectionpartspresentedalargefraction．There’Shardlyany13-crystalintwokindsofmicroparts．Thedegreeofcrystallinityofthemicropartsisdifferentatdifferentlocation．Thedegreeoforientationinmicropartwiththicknessof0．5mmishigherthatmicropartswi

7、ththicknessof1．0mm．2．Theinfluenceofinjectionspeedonmorphologyofmicroparts．Bymeansofpolarizedlightmicroscopy(PLM)andwideangleX-raydiffraction(WAXD)，theinfluenceoftheinjectionspeedonmorphologyevolutionofmicropartswasinvestigated．Theresultsshowthattwokindsofmic

8、ropartsexhibitedthesimilarskin—corestructureatlowinjectionspeed．Withtheinjectionspeedincreasing，theIIIABSTRACTfractionofshearlayerhaslittlechange．Themicropartsexhibitaspecificcore—freemorphology