Foamedplastics(alsocalledexpandedorcellularplastics)aremadebyaddingairorgastoaplasticresintoformasponge-likematerial.Moderndevelopmentsinplasticfoammoldinghaveplacedthisamongthemajorprocessingtechniquesoftheindustry.Resinscommonlyusedintheproductionofplas...[继续阅读]

    Manydifferentprocessesareusedtotransformplasticgranules,powders,andliquidsintofinalproducts.Theplasticmaterialisinmoldableform,andisadaptabletovariousformingmethods.Inmostcasesthermoplasticmaterialsaresuitableforcertainprocesseswhilethermosettingmaterials...[继续阅读]

    Thermoformingplasticsheetmaterialinshortthermoformingisoneofthemajorprocessingtechniquesoftheplasticsindustryandalsooneoftheoldest.Sinceearlyattempts,abouttheturnofthecentury,toshapecellulosicsheet,theprocesshasgrownrapidly.Muchofthegrowthisduetoinnovativ...[继续阅读]

    Thermoplasticitemswithauniformcrosssectionareformedbyextrusion.Thisincludesmanyfamiliaritemssuchaspipe,hoseandtubing,gaskets,wireandcableinsulation,sheeting,window-framemoldingsandhousesiding.Moldingpowderisconveyeddownanelectricallyoroil-heatedbarrelbyar...[继续阅读]

    SincetheSecondWorldWar,polymericmaterialshavebeenthefastest-growingsegmentsoftheworldchemicalindustry.Ithasbeenestimatedthatmorethanathirdofthechemicalresearchmoneyisspentonpolymers,withacorrespondinglylargeproportionoftechnicalpersonnelworkinginthearea.A...[继续阅读]

    Vinylresinscoverabroadgroupofmaterialsthatrangeinpropertiesfromhardrigidproductstosoftflexibleformulations.Theyarederivedfromthe“vinyl”radical:CH2CH2.Variousatomsorsidegroupsmaybeattachedtothevinylradicaltoproducepolymersofvaryingproperties.Thelargestpoly...[继续阅读]

    Thematerialsusedinthesecategoriesallhavefinitedutiestoperformwithinarubberformulation.Therefore,eachwillbediscussedinthesequencealreadylistedearlierinlasttwolessons.Rubbers(hydrocarbon):　Reclaimrubbercanplayanimportantpartinthefunctionofgeneralorspecialis...[继续阅读]

    TheGlassTransitionIthaslongbeenknownthatamorphouspolymerscanexhibittwodistinctlydifferenttypesofmechanicalbehavior.Some,likepolymethylmethacrylate(Lucite,Plexiglas)andpolystyrene,arehard,rigid,glassyplasticsatroomtemperature,whileothers,forexample,polybut...[继续阅读]

    Thefirsteffortsofmanufacturingartificialfiberswereconnectedwiththeattemptstoutilizenaturalpolymers,primarilycelluloseandcasein,asrawmaterials.Althoughsyntheticpolymerswerealreadyknownatthattime,theywereconsideredmerelyascuriosawithoututilitarianvalue.Macr...[继续阅读]

    Asanappreciationforthemolecularstructureofpolymerswasgained,threemajorstructuralcategoriesemerged.TheseareillustratedschematicallyinFigure4.1.Figure4.1　SchematicdiagramofpolymerstructuresLinearIfapolymerisbuiltfromstrictlydifunctionalmonomers,theresultisa...[继续阅读]