简介:摘要本文阐述了带式输送机组成,另外分析输送带跑偏、撒料、减速机断轴、胶带机皮带打滑等故障的原因,提出了处理措施。
简介:摘要结合某一带式输送机栈桥工程,详细介绍了该工程钢桁架吊装具体施工技术。包括吊车的计算与选用、吊装前的准备、吊装机具及绳索的选择、吊装施工技术措施,旨在为从事带式输送机栈桥工程的技术人员提供一些借鉴意义。
简介:摘要:随着人们环保、安全意识的加强,具备阻燃性能的材料在日常生活以及工业领域的应用越来越广泛,无卤阻燃材料成为了近年来的研究热点。本研究主要采用熔融加工法,以聚苯乙烯(Polystyrene,PS)为基材,尼龙粘土(NylonClay,NYC)为添加物,在不同共混条件下制备PS/NYC纳米复合材料并对其阻燃性质进行一系列的探讨。关键词:聚苯乙烯尼龙粘土改性PS阻燃性纳米复合材料Studyonthepreparationofhighflame-retardantPS/NYCnanocompositesanditsflame-retardantpropertiesYuan-XinWang1,NingMa2,Fang-ChangTsai2*,TaoJiang2,ShengWen3,Gen-WenZheng3(1.YichangFireDetachment,HubeiYichang443000,China;2.FacultyofMaterialScienceandEngineering,HubeiUniversity,Wuhan,Hubei430062,China;3.FacultyofChemistryandMaterialScience,XiaoganUniversity,Xiaogan,Hubei432100,China)AbstractWiththestrengtheningofenvironmentalandsafetyawareness,flame-retardantmaterialsaremoreextensiveusedineverydaylifeandindustrialfield,andhalogen-freeflame-retardantmaterialsbecomearesearchhotspotinrecentyears.Thisstudy,Polystyrene(PS)asasubstrate,NylonClay(NYC)asadditives,preparesPS/NYCnano-compositesunderthedifferentblendingconditionsbymeltprocessingmethodsandmakesaseriesofstudyofitsflameretardant.【Keywords】polystyreneNylonClaymodifiedpolystyreneflameretardantNanocomposites1绪论通过共混改性、填充增强,使PS获得优良的综合性能一直是一个重要研究课题。改性PS的发展趋势有:(1)在不显著损失模量的前提下增加其韧性[1,2];(2)与其他聚合物形成合金,但要提高相容性;(3)随着人们环保意思的加强,PS无卤阻燃材料成为了近年来的研究热点[3-5];(4)PS作为阻燃材料时必须进行阻燃改性[6],近年来PS阻燃改性通常采用无卤化阻燃技术[7].在PS/膨胀阻燃剂复合材料中加入热塑性弹性体苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)、苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)等,希望能进一步改善材料的力学性能;(5)PS作为阻燃材料,要提高阻燃性能,要抑制淌落现象的产生以及控制生烟量,逐渐形成纳米化,无毒化,环保化......
简介:Inordertopredictthemechanicalperformanceofthepolyvinylchloride(PVC)atahighoperatingtemperature,aseriesofshort-termtensilecreeptests(onetenthofthephysicalagingtime)ofthePVCarecarriedoutat63Cwithasmallconstantstressbyadynamicmechanicalanalyzer(DMA).TheStruik-Kohlrausch(SK)formulaandStruikshiftingmethodsareusedtodescribethesecreepdataforvariousphysicalagingtime.AnewphenomenologicalmodelbasedonthemultiplerelaxationmechanismsofanamorphouspolymerisdevelopedtoquantitativelycharacterizetheSKparameters(theinitialcreepcompliance,thecharacteristicretardationtime,andtheshapefactor)determinedbytheagingtime.ItisshownthatthemomentarycreepcompliancecurveofthePVCat63CcanbeverywellfittedbytheSKformulaforeachagingtime.However,theSKparametersforthecreepcurvesarenotconstantduringtheagingprocessattheelevatedtemperatures,andtheevolutionoftheseparametersandthecreeprateversusagingtimecurvesatthedoublelogarithmiccoordinateshaveshownanonlinearphenomenon.Moreover,thecreepmastercurvesobtainedbythesuperpositionwiththeStruikshiftingmethodsareunsatisfactoryinsuchacase.Finally,thepredictedresultscalculatedfromthepresentmodelincorporatingwiththeSKformulaareinexcellentagreementwiththecreepexperimentaldataforthePVCisothermallyagedatthetemperaturerelativelyclosetotheglasstransitiontemperature.