Modification of epoxy resins with polysiloxane

《Modification of epoxy resins with polysiloxane》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、PolymerVol.37No.13,pp.2733-2742,1996Copyright©1996ElsevierScienceLtdPrintedinGreatBritain.AllrightsreservedELSEVIER0032-3861/96/$15.00+0.00Modificationofepoxyresinswithpolysiloxanethermoplasticpolyurethaneforelectronicencapsulation:1Tsung-HanHoDepartmentof

2、ChemicalEngineering.NationalKaohsiungInstituteofTechnology,Kaohsiung,Taiwan807,RepublicofChinaandChun-ShanWang*DepartmentofChemicalEngineering.NationalChengKungUniversity,Tainan,Taiwan701,RepublicofChina(Received24October1995)Astabledispersionofpolysiloxan

3、ethermoplasticpolyurethane(TPU)particlesinanepoxyresinmatrixwasachievedviaepoxyringopeningwiththeisocyanategroupsofurethaneprepolymertoformanoxazolidone.TheeffectsofthestructureandmolecularweightofthepolysiloxaneTPUinreducingthestressofelectronicencapsulan

4、tswereinvestigated.ThemechanicalanddynamicviscoelasticpropertiesofpolysiloxaneTPU-modifiedepoxynetworkswerealsostudied.Aphase-separatedstructurewasobservedviascanningelectronmicroscopy.ThedispersedpolysiloxaneTPUrubberseffectivelyreducethestressofcuredepox

5、yresinsbyreducingtheflexuralmodulusandthecoefficientofthermalexpansion,whiletheglasstransitiontemperatureisincreasedbecauseoftheformationoftherigidoxazolidonestructure.ElectronicdevicesencapsulatedwiththepolysiloxaneTPU-modifiedepoxymouldingcompoundshaveex

6、hibitedanexcellentresistanceinthethermalshockcyclingtestandhaveresultedinanextendeddeviceusedlife.Copyright©1996ElsevierScienceLtd.(Keywords:epoxyresin;encapsulatingmaterials;polysiloxaneTPU)INTRODUCTIONconsideredtobeshrinkageoftheplasticuponcuringandtherm

7、almismatchbetweentheresinandthedevice.InEpoxymouldingcompounds(EMCs)havebeenwidelythecaseofEMCencapsulation,thefirstsourceofusedasencapsulationmaterialsforsemiconductorshrinkagehasbeenrelativelyminor,whereastheseconddevicesinordertoprotectthemfromtheirsurr

8、oundingsone,whichiscausedbythedifferenceinthermalandconnectthemtoprintedcircuitboardsI.Becauseofexpansioncoefficientsbetweenresinandsiliconchip,isitsexcellentheat,moisture,solventandchemicalthedominantfactor.