湘大高分子专业英语Charpter-4-1

Charpter4-1Polymerengineeringisgenerallyanengineeringfieldthatdesigns,analyses,and/ormodifiespolymermaterials.Polymerengineeringcoversaspectsofpetrochemicalindustry,polymerization,structureandcharacterizationofpolymers,propertiesofpolymers,compoundingandprocessingofpolymersanddescriptionofmajorpolymers,structurepropertyrelationsandapplications.高分子工程一般是设计，分析和/或改性高分子材料的工程领域。高分子工程涵盖石化工业，聚合反应，聚合物的结构和表征，聚合物的性能，聚合物的复合和加工和主要聚合物的描述，结构与性能关系和应用。4.1.PolymerProcessing4.1.1IntroductionPolymerprocessingcanbedefinedastheprocesswherebyrawmaterialsareconvertedintoproductsofdesiredshapeandproperties.Thermoplasticresinsaregenerallysuppliedaspellets,marbles,orchipsofvaryingsizes,andtheymaycontainsomeorallofthedesiredadditives.WhenheatedabovetheirTg,thermoplasticmaterialssoftenandflowasviscousliquidsthatcanbeshapedusingavarietyoftechniquesandthencooledto“lock”inthemicro-andgrossstructure.Thermosettingfeedstocksarenormallysuppliedasmeltableand/orflowableprepolymer,oligomers,orlightlyornoncrosslinkedpolymersthataresubsequentlycrosslinkedformingthethermosetarticle.Theprocessingoperationcanbedividedintothreegeneralsteps:preshaping,shaping,andpostshaping.Inpreshaping,theintentistoproduceamaterialthatcanbeshapedbyapplicationofheatand/orpressure.4.1.聚合物加工4.1.1介绍聚合物加工可以被定义为由原料转化为所需形状和性能的产品的过程。热塑性树脂一般是提供棒状的，球状的，或者碎片状的不同的尺寸，并且它们可能包含一些或所有所需的添加剂。当加热温度高于Tg时，热塑性材料软化并像粘性液体一样能流动，这可使用多种技术做成各种形状，然后冷却“锁定”在微毛和宏观结构中。热固性原料通常提供的可熔化的和/或可流动的​​预聚物，低聚物，或轻或非交联聚合物，随后形成交联的热固性物品。加工操作可以分为三个一般步骤：预成形，成形和后成形。在预成形时，其目的是产生一个可以通过加热和/或压力成型的材料。Therighttablelistssomeofthemajorformsofeachoftheseprocessinggroups.Processingandperformanceareinterrelatedtooneanotherandtoadditionalfactors.TableMajorFormsofPolymerProcessingGroupingsProcessTypicalformofproductCalenderingFilm,sheetsCoatingFilmInjectionSolidReactioninjectedReciprocatingscrewTwo-stageMoldingBlowHollowDisplacementExtrusionInjection/transferStretchClodsolidCompressionSolid,hollowRotationalSolid,hollowThermoformingHollowTransferSolidSpinningFibersDryGelMeltReactionWet右表列出了每种加工组的主要形式。加工和性能与互相之间和附加因素相联系的。表高分子材料加工租的主要形式ProcessTypicalformofproduct压延成型Film,sheets涂膜成型Film注射成型SolidReactioninjectedReciprocatingscrewTwo-stage模塑成型BlowHollowDisplacementExtrusionInjection/transferStretchClodsolidCompressionSolid,hollowRotationalSolid,hollowThermoformingHollowTransferSolid纺丝成型FibersDryGelMeltReactionWetJafferelatesthesemajorgroupsoffactorsinaninteractivediamondgivenbelow(Figure).Understandingthesefactorsandtheirinterrelationshipsbecomesincreasinglyimportantasthespecificperformancerequirementsbecomemorespecific.Performanceisrelatedtothechemicalandphysicalstructureandtotheparticularprocessingperformedonthematerialduringitslifetime.Thephysicalstructureisareflectionofboththechemicalstructureandthetotalhistoryofthesynthesisandsubsequentexposureofthematerialtoadditionalforces.These“additional”forcesareincludedunderthebroadideaofprocessingandincludeanyinfluencethatcontributestothesecondary(andgreater)structure—stress/strain,light,chemical,etc.Theportionofthediamondrelatingprocessingtophysicalstructureencompassesthestudyofstructure—propertyrelationships.FigureRelationshipsthatinfluencetheimportantinterrelationshipsthatexistforpolymericmaterialswithrespecttoprocessingandend-productproperties.Jaffe讲述了涉及下面给出（图）的交互式金刚石中这些因素主要群体。了解这些因素及其相互关系变得越来越重要，因为在具体的性能要求变得更加具体。性能相关的化学和物理结构，并在其寿命期内对材料进行特定的处理。的物理结构是两个化学结构及所合成的总的历史和该材料的随后暴露于额外的力的反映。这些“额外”的力包括加工的广泛构思之下，并包括，有助于二次（或更高）structure-stress/strain任何影响，光，化学等相关处理，以物理结构的金刚石的一部分包含了研究结构与性能的关系。图的关系影响，对于聚合物材料存在相对​​于加工和最终产品性能的重要相互关系。4.1.2EffectofPolymerStructureonProcessingPrimaryandsecondarystructuresgreatlyinfluencepossibleprocessingscenarios.Here,thesecondarystructureisgenerallythesameasthephysicalstructureandtheprimarystructureisgenerallythesameasthechemicalstructure.Theendpropertiesandusesaregovernedbyintrinsicpropertiesthat,inturn,arerelatedtotheprimaryandsecondarystructure—thechemicalandphysicalstructures.Theterm“meso”willbeusedtodescribelocalchainorganizationsthatoccurwithinthenano-andmicroscaleregions(Fig.).Whilethetermsmesophaseandmesoregionshavebeenemployedindescribingorderwithinliquidcrystals,thedefinitionwillbebroadenedtoincludeotherorderedregionswithinamaterial’sphysicalorsecondarystructure.Wegenerallydescribeapolymer’ssecondarystructure,insimpletermsoforderedanddisorderedorcrystallineandamorphous.FigureRelationshipbetweenorganizationallevelandsize.4.1.2高分子结构对加工的影响初级和二级结构极大地影响可能的处理方案。这里，二级结构是大致相同的物理结构和一级结构是大致相同的化学结构。末的性能和用途是将其反过来，都涉及到的初级和次级结构的化学和物理结构固有特性支配。术语“内消旋”将被用于描述在纳米和微米级的区域（图3）中发生的局部连锁机构。而条款中间相和mesoregions已受聘于液晶内描述顺序，定义将被扩大到材料的物理或二级结构中包含其他有序的区域。我们通常描述的聚合物的二级结构，以深入浅出的有序和无序或结晶和无定形。图组织层次和规模之间的关系。Jaffedescribesfourmesophaseclassifications.Permanentmesogensarematerialswhosemicrostructuresarehighlyfixedsuchasinliquidcrystallinepolymers(LCs).LCsarecharacterizedbyhighlyorderedstructuresinthequiescentstate.Theyexhibitrelativelylowviscositiesinuniaxielflowsandcanbeeasilyrealignedthroughapplicationofprocessingforcessuchasextrusion.Tobeprocessed,suchpolymersmustbeinthemesogenicstatebelowtheirdec