19 第19 課 試劑和膠黏劑

GangDongPolytechnicTeacher：XuFengLiuReagent&

AdhesiveReagentPart1Reagent

Areagentorreactantisamaterialusedtostartachemicalreaction.Forexamplehydrochloricacidisthechemicalreagentthatwouldcausecalciumcarbonatetoreleasecarbondioxide.Similarly,butlessobvious,hydrochloricacidisthechemicalreagentthatreactswithzinctoproducehydrogen,eventhoughinthiscasethehydrogencomesfromtheacidandnotthemetal.Toclassifyanyofthechemicals

involvedinachemicalreactionasthe"reagent"isthus

largelyamatterofconventionorperspective.試劑

試劑或反應(yīng)物是用來引發(fā)化學(xué)反應(yīng)的材料。例如，鹽酸是會(huì)和碳酸鈣反應(yīng)釋放二氧化碳的化學(xué)試劑。類似地，但不那么明顯的是，鹽酸是一種與鋅反應(yīng)生成氫的化學(xué)試劑，盡管在這種情況下，氫來自于酸而不是金屬。因此，將任何參與化學(xué)反應(yīng)的化學(xué)物質(zhì)歸類為“試劑”在很大程度上是一種慣例或看法的問題。Reagent

Inanotheruseoftheterm,whenpurchasingorpreparingchemicals"reagent"describeschemicalsubstancesofsufficientpurityforuseinchemicalanalysis,

chemicalreactionsorphysicaltesting.

這一術(shù)語的另一個(gè)用法是，在購買或制備化學(xué)品時(shí)，“試劑”指的是在化學(xué)分析、化學(xué)反應(yīng)或物理測(cè)試中使用的足夠純度的化學(xué)物質(zhì)。試劑AdhesivePart2Adhesive

Adhesiveissubstancecapableofstickingtosurfacesofothersubstancesandbondingthemtooneanother.Thetermadhesivecementissometimesusedinplaceofadhesive,especiallywhenreferringtoasyntheticadhesive.膠黏劑

膠粘劑是一種能夠粘在其他物質(zhì)表面并使它們相互粘合的物質(zhì)。膠漿這一術(shù)語有時(shí)用來代替膠黏劑，特別是指合成膠黏劑時(shí)。Adhesive

Animalglue,agelatinmadefromhides,hooves,orbones

wasprobablyknown

inprehistorictimes；itremainedtheleadingadhesiveuntilthe20thcent.Itisnowusedespeciallyincabinetmaking.Animalglueissoldbothasasolid(eithergroundorinsheets,tobemeltedinawater-jacketedgluepotandappliedwhilehot)andasliquidglue(anacidicsolution).膠黏劑

動(dòng)物膠，一種由獸皮、蹄子或骨頭制成的明膠，可能在史前時(shí)代就已為人所知;直到20世紀(jì)初，它仍然是主要的粘合劑，現(xiàn)在尤其用于家具制作。動(dòng)物膠既可以是固體(磨碎的或片狀的，在有水的膠罐里融化，趁熱涂上)，也可以是液體的(酸性溶液)。Adhesive

Adhesivesfromvegetablesourcesarealsoimportant；theyincludenaturalgumsandresins,mucilage

andstarchandstarchderivatives.Theyarecommonlyusedforsizingpaperandtextilesandforlabeling,sealing,andmanufacturing

papergoods.膠黏劑

植物來源的粘合劑也很重要，它們包括天然膠和樹脂、粘液、淀粉和淀粉衍生物。它們通常用于紙張和紡織品的上醬，也用于貼標(biāo)，密封和制造紙制品中。AdhesiveOtheradhesivesderivedfromanimalandvegetablesourcesincludebloodglue,caseinglue,fishglue,rubberadhesives

andcellulosederivatives.Adhesiveshavingspecialpropertiesarepreparedfromsyntheticresins.Somesyntheticadhesives,

suchastheepoxyresins,

arestrongenoughtobeused

inconstructioninplaceo