(完整word版)高分子材料工程專業(yè)英語第二版課文翻譯基本全了

(完整word版)高分子材料工程專業(yè)英語第二版課文翻譯(基本全了(完整word版)高分子材料工程專業(yè)英語第二版課文翻譯(基本全了PAGEPAGE11(完整word版)高分子材料工程專業(yè)英語第二版課文翻譯(基本全了A高分子化學(xué)和高分子物理UNIT1WhatarePolymer？第一單元什么是高聚物？Whatarepolymers？Foronething,theyarecomplexandgiantmoleculesandaredifferentfromlowmolecularweightcompoundslike,say,commonsalt.Tocontrastthedifference，themolecularweightofcommonsaltisonly58。5，whilethatofapolymercanbeashighasseveralhundredthousand,evenmorethanthousandthousands。Thesebigmoleculesor‘macro—molecules'aremadeupofmuchsmallermolecules，canbeofoneormorechemicalcompounds.Toillustrate,imaginethatasetofringshasthesamesizeandismadeofthesamematerial.Whenthesethingsareinterlinked，thechainformedcanbeconsideredasrepresentingapolymerfrommoleculesofthesamecompound.Alternatively，individualringscouldbeofdifferentsizesandmaterials，andinterlinkedtorepresentapolymerfrommoleculesofdifferentcompounds。什么是高聚物？首先,他們是合成物和大分子，而且不同于低分子化合物，譬如說普通的鹽。與低分子化合物不同的是，普通鹽的分子量僅僅是58.5，而高聚物的分子量高于105，甚至大于106。這些大分子或“高分子"由許多小分子組成。小分子相互結(jié)合形成大分子，大分子能夠是一種或多種化合物.舉例說明，想象一組大小相同并由相同的材料制成的環(huán).當(dāng)這些環(huán)相互連接起來，可以把形成的鏈看成是具有同種分子量化合物組成的高聚物。另一方面，獨(dú)特的環(huán)可以大小不同、材料不同，相連接后形成具有不同分子量化合物組成的聚合物.Thisinterlinkingofmanyunitshasgiventhepolymeritsname,polymeaning‘many’andmermeaning‘part’（inGreek)。Asanexample，agaseouscompoundcalledbutadiene，withamolecularweightof54,combinesnearly4000timesandgivesapolymerknownaspolybutadiene(asyntheticrubber）withabout200000molecularweight。Thelowmolecularweightcompoundsfromwhichthepolymersformareknownasmonomers。Thepictureissimplyasfollows:許多單元相連接給予了聚合物一個(gè)名稱，poly意味著“多、聚、重復(fù)”，mer意味著“鏈節(jié)、基體”(希臘語中）。例如：稱為丁二烯的氣態(tài)化合物,分子量為54,化合將近4000次，得到分子量大約為200000被稱作聚丁二烯（合成橡膠)的高聚物。形成高聚物的低分子化合物稱為單體。下面簡單地描述一下形成過程：butadiene+butadiene+???+butadiene—-→polybutadiene(4000time）丁二烯＋丁二烯＋…＋丁二烯—-→聚丁二烯（4000次）Onecanthusseehowasubstance（monomer）withassmallamoleculeweightas54growtobecomeagiantmolecule（polymer）of(54×4000≈）200000molecularweight。Itisessentiallythe‘giantness'ofthesizeofthepolymermoleculethatmakesitsbehaviordifferentfromthatofacommonlyknownchemicalcompoundsuchasbenzene.Solidbenzene，forinstance，meltstobecomeliquidbenzeneat5.5℃因而能夠看到分子量僅為54的小分子物質(zhì)（單體）如何逐漸形成分子量為200000的大分子（高聚物).實(shí)質(zhì)上，正是由于聚合物的巨大的分子尺寸才使其性能不同于象苯這樣的一般化合物.例如，固態(tài)苯，在5。5℃熔融成液態(tài)苯,進(jìn)一步加熱，煮沸成氣態(tài)苯.與這類簡單化合物明確的行為相比，像聚乙烯這樣的聚合物不能在某一特定的溫度快速地熔融成純凈的液體。而聚合物變得越來越軟,最終,變成十分粘稠的聚合物熔融體。將這種熱而粘稠的聚合物熔融體進(jìn)一步加熱,不會轉(zhuǎn)變成各種氣體，但它不再是聚乙烯（如圖1.1）。固態(tài)苯—-→液態(tài)苯-—→氣態(tài)苯加熱，5。5℃加熱,80℃固體聚乙烯——→熔化的聚乙烯——→各種分解產(chǎn)物—但不是聚乙烯加熱加熱圖1。1低分子量化合物(苯）和聚合物（聚乙烯）受熱后的不同行為Anotherstrikingdifferencewithrespecttothebehaviorofapolymerandthatofalowmolecularweightcompoundconcernsthedissolutionprocess.Letustake,forexample，sodiumchlorideandadditslowlytosfixedquantityofwater.Thesalt，whichrepresentsalowmolecularweightcompound，dissolvesinwateruptospoint(calledsaturationpoint)but，thereafter,anyfurtherquantityaddeddoesnotgointosolutionbutsettlesatthebottomandjustremainsthereassolid。Theviscosityofthesaturatedsaltsolutionisnotverymuchdifferentfromthatofwater.Butifwetakeapolymerinstead,say，polyvinylalcohol,andaddittoafixedquantityofwater，thepolymerdoesnotgointosolutionimmediately.Theglobulesofpolyvinylalcoholfirstabsorbwater,swellandgetdistortedinshapeandafteralongtimegointosolution。Also，wecanaddaverylargequantityofthepolymertothesamequantityofwaterwithoutthesaturationpointeverbeingreached。Asmoreandmorequantityofpolymerisaddedtowater，thetimetakenforthedissolutionofthepolymerobviouslyincreasesandthemixultimatelyassumesasoft，dough-likeconsistency。Anotherpeculiarityisthat,inwater,polyvinylalcoholneverretainsitsoriginalpowderynatureastheexcesssodiumchloridedoesinasaturatedsaltsolution。Inconclusion，wecansaythat(1）thelongtimetakenbypolyvinylalcoholfordissolution,(2）theabsenceofasaturationpoint,and（3)theincreaseintheviscosityareallcharacteristicsofatypicalpolymerbeingdissolvedinasolventandthesecharacteristicsareattributedmainlytothelargemolecularsizeofthepolymer。ThebehaviorofalowmolecularweightcompoundandthatofapolymerondissolutionareillustratedinFig。1。2.發(fā)現(xiàn)另一種不同的聚合物行為和低分子量化合物行為是關(guān)于溶解過程。例如，讓我們研究一下,將氯化鈉慢慢地添加到固定量的水中。鹽，代表一種低分子量化合物,在水中達(dá)到點(diǎn)（叫飽和點(diǎn)）溶解，但，此后，進(jìn)一步添加鹽不進(jìn)入溶液中卻沉到底部而保持原有的固體狀態(tài)。飽和鹽溶液的粘度與水的粘度不是十分不同，但是,如果我們用聚合物替代，譬如說，將聚乙烯醇添加到固定量的水中，聚合物不是馬上進(jìn)入到溶液中。聚乙烯醇顆粒首先吸水溶脹，發(fā)生形變,經(jīng)過很長的時(shí)間以后進(jìn)入到溶液中。同樣地，我們可以將大量的聚合物加入到同樣量的水中，不存在飽和點(diǎn)。將越來越多的聚合物加入水中，認(rèn)為聚合物溶解的時(shí)間明顯地增加，最終呈現(xiàn)柔軟像面團(tuán)一樣粘稠的混合物。另一個(gè)特點(diǎn)是，在水中聚乙烯醇不會像過量的氯化鈉在飽和鹽溶液中那樣能保持其初始的粉末狀態(tài)?？傊覀兛梢灾v（1）聚乙烯醇的溶解需要很長時(shí)間,(2）不存在飽和點(diǎn),（3)粘度的增加是典型聚合物溶于溶液中的特性，這些特性主要?dú)w因于聚合物大分子的尺寸。如圖1.2說明了低分子量化合物和聚合物的溶解行為。氯化鈉晶體加入到水中——→晶體進(jìn)入到溶液中.溶液的粘度不是十分不同于充分?jǐn)嚢杷恼扯取纬娠柡腿芤?剩余的晶體維持不溶解狀態(tài).加入更多的晶體并攪拌氯化鈉的溶解聚乙烯醇碎片加入到水中—-→碎片開始溶脹—-→碎片慢慢地進(jìn)入到溶液中允許維持現(xiàn)狀充分?jǐn)嚢琛纬烧吵淼木酆衔锶芤?溶液粘度十分高于水的粘度繼續(xù)攪拌聚合物的溶解圖1.2低分子量化合物（氯化鈉）和聚合物(聚乙烯醇）不同的溶解行為——GowarikerVR,ViswanathanNV,SreedharJ.PolymerScience.NewYork:JohnWiley&Sons，1986。6UNIT2ChainPolymerization第二單元鏈?zhǔn)骄酆戏磻?yīng)Manyolefinicandvinylunsaturatedcompoundsareabletoformchain—0likemacromoleculesthrougheliminationofthedoublebond,aphenomenonfirstrecognizedbyStaudinger.Diolefinspolymerizeinthesamemanner,however，onlyoneofthetwodoublebondsiseliminated。Suchreactionsoccurthroughtheinitialadditionofamonomermoleculetoaninitiatorradicaloraninitiatorion,bywhichtheactivestateistransferredfromtheinitiatortotheaddedmonomer.Inthesamewaybymeansofachainreaction,onemonomermoleculeaftertheotherisadded(2000～20000monomerspersecond）untiltheactivestateisterminatedthroughadifferenttypeofreaction。Thepolymerizationisachainreactionintwoways：becauseofthereactionkineticandbecauseasareactionproductoneobtainsachainmolecule。Thelengthofthechainmoleculeisproportionaltothekineticchainlength。Staudinger第一個(gè)發(fā)現(xiàn)一例現(xiàn)象，許多烯烴和不飽和烯烴通過打開雙鍵可以形成鏈?zhǔn)酱蠓肿?二烯烴以同樣的方式聚合,然而,僅限于兩個(gè)雙鍵中的一個(gè)。這類反應(yīng)是通過單體分子首先加成到引發(fā)劑自由基或引發(fā)劑離子上而進(jìn)行的,靠這些反應(yīng)活性中心由引發(fā)劑轉(zhuǎn)移到被加成的單體上。以同樣的方式，借助于鏈?zhǔn)椒磻?yīng)，單體分子一個(gè)接一個(gè)地被加成（每秒2000~20000個(gè)單體)直到活性中心通過不同的反應(yīng)類型而終止。聚合反應(yīng)是鏈?zhǔn)椒磻?yīng)的原因有兩種:因?yàn)榉磻?yīng)動力學(xué)和因?yàn)樽鳛榉磻?yīng)產(chǎn)物它是一種鏈?zhǔn)椒肿?。鏈分子的長度與動力學(xué)鏈長成正比。Onecansummarizetheprocessasfollow(R.isequaltotheinitiatorradical)：鏈?zhǔn)椒磻?yīng)可以概括為以下過程（R·相當(dāng)與引發(fā)劑自由基）:略O(shè)nethusobtainspolyvinylchloridefromvinylchloride,orpolystyrenefromstyrene,orpolyethylenefromethylene,etc.因而通過上述過程由氯乙烯得到聚氯乙烯,或由苯乙烯獲得聚苯乙烯，或乙烯獲得聚乙烯,等等。Thelengthofthechainmolecules,measuredbymeansofthedegreeofpolymerization,canbevariedoveralargerangethroughselectionofsuitablereactionconditions.Usually,withcommerciallypreparedandutilizedpolymers，thedegreeofpolymerizationliesintherangeof1000to5000,butinmanycasesitcanbebelow500andover10000。Thisshouldnotbeinterpretedtomeanthatallmoleculesofacertainpolymericmaterialconsistof500，or1000，or5000monomerunits.Inalmostallcases,thepolymericmaterialconsistsofamixtureofpolymermoleculesofdifferentdegreesofpolymerization.借助于聚合度估算的分子鏈長，在一個(gè)大范圍內(nèi)可以通過選擇適宜的反應(yīng)條件被改變。通常，通過大量地制備和利用聚合物，聚合度在1000~5000范圍內(nèi)，但在許多情況下可低于500、高于10000。這不應(yīng)該把所有聚合物材料的分子量理解為由500,或1000，或5000個(gè)單體單元組成。在幾乎所有的事例中，聚合物材料由不同聚合度的聚合物分子的混合物組成。Polymerization，achainreaction,occursaccordingtothesamemechanismasthewell-knownchlorine—hydrogenreactionandthedecompositionofphosegene.聚合反應(yīng)，鏈?zhǔn)椒磻?yīng)，依照與眾所周知的氯(氣）—?dú)洌猓┓磻?yīng)和光氣的分解機(jī)理進(jìn)行。Theinitiationreaction,whichistheactivationprocessofthedoublebond,canbebroughtaboutbyheating，irradiation,ultrasonics,orinitiators.Theinitiationofthechainreactioncanbeobservedmostclearlywithradicalorionicinitiators.Theseareenergy-richcompoundswhichcanaddsuitableunsaturatedcompounds（monomers）andmaintaintheactivatedradical，orionic，statesothatfurthermonomermoleculescanbeaddedinthesamemanner。Fortheindividualstepsofthegrowthreactiononeneedsonlyarelativelysmallactivationenergyandthereforethroughasingleactivationstep(theactualinitiationreaction）alargenumberofolefinmoleculesareconverted，asisimpliedbytheterm“chainreaction”。Becauseverysmallamountsoftheinitiatorbringabouttheformationofalargeamountofpolymericmaterial(1:1000to1:1000)，itispossibletoregardpolymerizationfromasuperficialpointofviewasacatalyticreaction.Forthisreason,theinitiatorsusedinpolymerizationreactionsareoftendesignatedaspolymerizationcatalysts,eventhough，inthestrictestsense，theyarenottruecatalystsbecausethepolymerizationinitiatorentersintothereactionasarealpartnerandcanbefoundchemicallyboundinthereactionproduct，i.e.，thepolymer，Inadditiontotheionicandradicalinitiatorstherearenowmetalcomplexinitiators（whichcanbeobtained，forexample，bythereactionoftitaniumtetrachlorideortitaniumtrichloridewithaluminumalkyls），whichplayanimportantroleinpolymerizationreactions（Zieglercatalysts），Themechanismoftheircatalyticactionisnotyetcompletelyclear。雙鍵活化過程的引發(fā)劑反應(yīng),可以通過熱、輻射、超聲波或引發(fā)劑產(chǎn)生。用自由基型或離子型引發(fā)劑引發(fā)鏈?zhǔn)椒磻?yīng)可以很清楚地進(jìn)行觀察。這些是高能態(tài)的化合物，它們能夠加成不飽和化合物(單體）并保持自由基或離子活性中心以致單體可以以同樣的方式進(jìn)一步加成。對于增長反應(yīng)的各個(gè)步驟，每一步僅需要相當(dāng)少的活化能，因此通過一步簡單的活化反應(yīng)（即引發(fā)反應(yīng))即可將許多烯類單體分子轉(zhuǎn)化成聚合物,這正如連鎖反應(yīng)這個(gè)術(shù)語的內(nèi)涵那樣。因?yàn)樯倭康囊l(fā)劑引發(fā)形成大量的聚合物原料（1：1000~1：10000）,從表面上看聚合反應(yīng)很可能是催化反應(yīng)。由于這個(gè)原因，通常把聚合反應(yīng)的引發(fā)劑看作是聚合反應(yīng)的引發(fā)劑，但是，嚴(yán)格地講它們不是真正意義上的催化劑,因?yàn)榫酆戏磻?yīng)的催化劑進(jìn)入到反應(yīng)內(nèi)部而成為一部分，同時(shí)可以在反應(yīng)產(chǎn)物，既聚合物的末端發(fā)現(xiàn)。此外離子引發(fā)劑和自由基引發(fā)劑有的是金屬絡(luò)合物引發(fā)劑(例如，通過四氯化鈦或三氯化鈦與烷基鋁的反應(yīng)可以得到）,Z引發(fā)劑在聚合反應(yīng)中起到了重要作用,它們催化活動的機(jī)理還不是十分清楚。UNIT3Step-GrowthPolymerization第三單元逐步聚合Manydifferentchemicalreactionsmaybeusedtosynthesizepolymericmaterialsbystep-growthpolymerization.Theseincludeesterification,amidation,theformationofurethanes，aromaticsubstitution,etc.Polymerizationproceedsbythereactionsbetweentwodifferentfunctionalgroups，e。g.,hydroxylandcarboxylgroups，orisocyanateandhydroxylgroups。許多不同的化學(xué)反應(yīng)通過逐步聚合可用于合成聚合材料。這些反應(yīng)包括酯化、酰胺化、氨基甲酸酯、芳香族取代物的形成等.通過反應(yīng)聚合反應(yīng)在兩種不同的官能團(tuán)，如，羥基和羧基，或異氰酸酯和羥基之間。Allstep-growthpolymerizationfallintotwogroupsdependingonthetypeofmonomer(s)employed。Thefirstinvolvestwodifferentpolyfunctionalmonomersinwhicheachmonomerpossessesonlyonetypeoffunctionalgroup。Apolyfunctionalmonomerisonewithtwoormorefunctionalgroupspermolecule。Thesecondinvolvesasinglemonomercontainingbothtypesoffunctionalgroups.Thesynthesisofpolyamidesillustratesbothgroupsofpolymerizationreactions。Thus，polyamidescanbeobtainedfromthereactionofdiamineswithdiacids所有的逐步聚合反應(yīng)根據(jù)所使用單體的類型可分為兩類。第一類涉及兩種不同的官能團(tuán)單體，每一種單體僅具有一種官能團(tuán)。一種多官能團(tuán)單體每個(gè)分子有兩個(gè)或多個(gè)官能團(tuán)。第二類涉及含有兩類官能團(tuán)的單種單體。聚酰胺的合成說明了聚合反應(yīng)的兩個(gè)官能團(tuán)。因此聚酰胺可以由二元胺和二元酸的反應(yīng)或氨基酸之間的反應(yīng)得到。nH2N—R-NH2+nHO2C-R’-CO2H→H-（—NH-R—NHCO-R’—CO—)n—OH+（2n-1)H2O(3。1）orfromthereactionofaminoacidswiththemselvesnH2R—CO2H→H-(—NH-R—CO-）n-OH+（n—1）H20(3.2）ThetwogroupsofreactionscanberepresentedinageneralmannerbytheequationsasfollowsA+B-B→–［-A-A—B—B-］—A—B→–[-A—B—]-兩種官能團(tuán)之間的反應(yīng)一般來說可以通過下列反應(yīng)式表示反應(yīng)式略Reaction(3。1）illustratestheformer,while（3。2）isofthelattertype.反應(yīng)（3。1)說明前一種形式，而反應(yīng)(3.2）具有后一種形式。圖3。1逐步聚合的示意圖未反應(yīng)單體；（b)50%已反應(yīng)；（c）83.3％已反應(yīng)；(d)100％已反應(yīng)(虛線表示反應(yīng)種類）Polyesterification,whetherbetweendiolanddibasicacidorintermolecularlybetweenhydroxyacidmolecules,isanexampleofastep—growthpolymerizationprocess。Theesterificationreactionoccursanywhereinthemonomermatrixwheretwomonomermoleculescollide，andoncetheesterhasformed，it,too，canreactfurtherbyvirtueofitsstill—reactivehydroxylorcarboxylgroups.Theneteffectofthisisthatmonomermoleculesareconsumedrapidlywithoutanylargeincreaseinmolecularweight.Fig.3.1illustratesthisphenomenon.Assume,forexample,thateachsquareinFig.3.arepresentsamoleculeofhydroxyacid。Aftertheinitialdimmermoleculesfrom(b），halfthemonomermoleculeshavebeenconsumedandtheaveragedegreeofpolymerization(DP)ofpolymericspeciesis2.Astrimerandmoredimermoleculesform(c）,morethan80％ofthemonomermoleculeshavereacted（d)，DPis4。Buteachpolymermoleculethatformsstillhasreactiveendgroups;hencethepolymerizationreactionwillcontinueinastepwisefashion,witheachesterificationofmonomers。Thus，molecularweightincreasesslowlyevenathighlevelsofmonomerconversion，anditwillcontinuetoincreaseuntiltheviscositybuild-upmakesitmechanicallytoodifficulttoremovewaterofesterificationorforreactiveendgroupstofindeachother。聚酯化,是否在二元酸和二元醇或羥基酸分子間進(jìn)行，是逐步聚合反應(yīng)過程的一個(gè)例子。酯化反應(yīng)出現(xiàn)在單體本體中兩個(gè)單體分子相碰撞的位置，且酯一旦形成，依靠酯上仍有活性的羥基或羧基還可以進(jìn)一步進(jìn)行反應(yīng)。酯化的結(jié)果是單體分子很快地被消耗掉，而分子量卻沒有多少增加.圖3.1說明了這個(gè)現(xiàn)象.例如，假定圖3。1中的每一個(gè)方格代表一個(gè)羥基酸分子.（b）中的二聚體分子，消耗二分之一的單體分子聚合物種類的聚合度(DP)是2。(c)中當(dāng)三聚體和更多的二聚體形成,大于80％的單體分子已反應(yīng),但DP僅僅還是2。5。（d）中當(dāng)所有的單體反應(yīng)完,DP是4.但形成的每一種聚合物分子還有反應(yīng)活性的端基；因此，聚合反應(yīng)將以逐步的方式繼續(xù)進(jìn)行，其每一步酯化反應(yīng)的反應(yīng)速率和反應(yīng)機(jī)理均與初始單體的酯化作用相同。因此，分子量緩慢增加直至高水平的單體轉(zhuǎn)化率，而且分子量將繼續(xù)增加直到粘度的增加使其難以除去酯化反應(yīng)的水或難以找到相互反應(yīng)的端基。ItcanalsobeshownthatintheA—A+B-Btypeofpolymerization,anexactstoichiometricbalanceisnecessarytoachievehighmolecularweights.Ifsomemonofunctionalimpurityispresent,itsreactionwilllimitthemolecularweightbyrenderingachainendinactive.Similarly，high—puritymonomersarenecessaryintheA—Btypeofpolycondensationanditfollowsthathigh—yieldreactionsaretheonlypracticalonesforpolymerformation，sincesidereactionswillupsetthestoichiometricbalance.在A-A+B—B的聚合反應(yīng)中也可以看到，精確的當(dāng)量平衡是獲得高分子量所必需的。假如存在一些但官能團(tuán)雜質(zhì)，由于鏈的端基失活，反應(yīng)將使分子量減少。同樣，在A—B類的縮聚反應(yīng)中高純度的單體是必要的，而且可以歸結(jié)高收率的反應(yīng)僅是形成聚合物的實(shí)際反應(yīng)，因?yàn)楦狈磻?yīng)會破壞當(dāng)量平衡.-——-——-StevensMP.PolymerChemistry.London:Addison—WesleyPublishingCompany,1975.13UNIT4IonicPolymerization第四單元離子聚合反應(yīng)Ionicpolymerization，similartoradialpolymerization，alsohasthemechanismofachainreaction。Thekineticsofionicpolymerizationare，however，considerablydifferentfromthatofradicalpolymerization.離子聚合反應(yīng)，與自由基聚合反應(yīng)相似，也有鏈反應(yīng)的機(jī)理。但是，離子聚合的動力學(xué)明顯地不同于自由基聚合反應(yīng)。(1）Theinitiationreactionofionicpolymerizationneedsonlyasmallactivationenergy。Therefore，therateofpolymerizationdependsonlyslightlyonthetemperature。Ionicpolymerizationsoccurinmanycaseswithexplosiveviolenceevenattemperature.below50℃(forexample，theanionicpolymerizationofstyreneat–70℃intetrahydrofuran,orthecationicpolymerizationofisobutyleneat–（1)離子聚合的引發(fā)反應(yīng)僅需要很小的活化能。因此，聚合反應(yīng)的速率僅對溫度有較少的依賴性。在許多情況下離子聚合猛烈地發(fā)生甚至低于50℃（例如，苯乙烯的陰離子聚合反應(yīng)在—70℃(2)Withionicpolymerizationthereisnocompulsorychainterminationthroughrecombination,becausethegrowingchainscannotreactwitheachother.Chainterminationtakesplaceonlythroughimpurities，orthroughtheadditionofcertaincompoundssuchaswater,alcohols,acids，amines，oroxygen，andingeneralthroughcompoundswhichcanreactwithpolymerizationionsundertheformationofneutralcompoundsorinactiveionicspecies。Iftheinitiatorsareonlypartlydissociated，theinitiationreactionisanequilibriumreaction,wherereactioninonedirectiongivesrisetochaininitiationandintheotherdirectiontochaintermination。（2）對于離子聚合來說，不存在通過再結(jié)合反應(yīng)而進(jìn)行的強(qiáng)迫鏈終止,因?yàn)樯L鏈之間不能發(fā)生鏈終止。鏈終止反應(yīng)僅僅通過雜質(zhì)而發(fā)生，或者說通過和某些像水、醇、酸、胺或氧這樣的化合物進(jìn)行加成而發(fā)生，且一般來說（鏈終止反應(yīng)）可通過這樣的化合物來進(jìn)行，這種化合物在中性聚合物或沒有聚合活性的離子型聚合物生成的過程中可以和活性聚合物離子進(jìn)行反應(yīng)。如果引發(fā)劑僅僅部分地離解，引發(fā)反應(yīng)即為一個(gè)平衡反應(yīng)，在出現(xiàn)平衡反應(yīng)的場合，在一個(gè)方向上進(jìn)行鏈引發(fā)反應(yīng)，而在另一個(gè)方向上則發(fā)生鏈終止反應(yīng)。Ingeneralionicpolymerizationpolymerizationcanbeinitiatedthroughacidicorbasiccompounds.Forcationicpolymerization,complexesofBF3,AlCl3,TiCl4，andSnCl4withwater，oralcohols,ortertiaryoxoniumsaltshaveshownthemselvestobeparticularlyactive.Thepositiveionsaretheonesthatcausechaininitiation。Forexample:通常離子聚合反應(yīng)能通過酸性或堿性化合物被引發(fā)。對于陽離子聚合反應(yīng)來說，BF3,AlCl3,TiCl4和SnCl4與水、或乙醇，或叔烊鹽的絡(luò)合物提供了部分活性。正離子是產(chǎn)生鏈引發(fā)的化合物。例如:(反應(yīng)略)三乙基硼氟酸烊However,alsowithHCl,H2SO4,andKHSO4，onecaninitiatecationicpolymerization。Initiatorsforanionicpolymerizationarealkalimetalsandtheirorganiccompounds,suchasphenyllithium,butyllithium,phenylsodium,andtriphenylmethylpotassium，whicharemoreorlessstronglydissociatedindifferentsolvents.TothisgroupbelongalsothesocalledAlfincatalysts，whichareamixtureofsodiumisopropylate,allylsodium，andsodiumchloride.然而，BF3也可以與HCl、H2SO4和KHSO4引發(fā)陽離子聚合反應(yīng)。陰離子聚合反應(yīng)的引發(fā)劑是堿金屬和它們的有機(jī)金屬化合物，例如苯基鋰、丁基鋰和三苯甲基鋰，它們在不同的溶劑中或多或少地強(qiáng)烈分解。所謂的Alfin催化劑就是屬于這一類，這類催化劑是異丙醇鈉、烯丙基鈉和氯化鈉的混合物。WithBF3(andisobutyleneasthemonomer），itwasdemonstratedthatthepolymerizationispossibleonlyinthepresenceoftracesoftracesofwateroralcohol.Ifoneeliminatesthetraceofwater，BF3alonedoesnotgiverisetopolymerization。WateroralcoholsarenecessaryinordertoallowtheformationoftheBF3—complexandtheinitiatorcationaccordingtotheabovereactions。However，oneshouldnotdescribethewaterorthealcoholasa“cocatalyst"。BF3為引發(fā)劑（異丁烯為單體）,證明僅在痕量水或乙醇的存在下聚合反應(yīng)是可以進(jìn)行的。如果消除痕量的水，單純的BF3不會引發(fā)聚合反應(yīng).按照上述反應(yīng)為了能形成BF3-絡(luò)合物和引發(fā)劑離子水或乙醇是必需的。但是不應(yīng)將水或乙醇描述成“助催化劑"。Justasbyradicalpolymerization，onecanalsopreparecopolymersbyionicpolymerization，forexample,anioniccopolymersofstyreneandbutadiene,orcationiccopolymersofisobutyleneandstyrene,orisobutyleneandvinyethers，etc。Ashasbeendescribedindetailwithradicalpolymerization,onecancharacterizeeachmonomerpairbyso—calledreactivityratiosr1andr2。Theactualvaluesofthesetwoparametersare，however,differentfromthoseusedforradicalcopolymerization.正與自由基聚合反應(yīng)一樣，通過離子聚合反應(yīng)也能制備共聚物，例如，苯乙烯—丁二烯陰離子共聚物，或異丁烯—苯乙烯陽離子共聚物,或異丁烯-乙烯基醚共聚物，等等。正如對自由基型聚合已經(jīng)詳細(xì)描述過那樣，人們可以用所謂的競聚率r1和r2來表征每單體對.然而，這兩個(gè)參數(shù)的實(shí)際意義不同于那些用于自由基共聚合反應(yīng)的參數(shù).—--VollmertB.PolymerChemistry。Berlin:Sping-Verlag,1973。163PARTB聚合反應(yīng)工程UNIT11Reactortypes第十一單元反應(yīng)器類型Reactorsmaybecategorizedinavarietyofways，eachappropriatetoaparticularperspective。Forexample，Henglein(1969）choosesabreakdownbasedonthesourceofenergyusedtoinitiatethereaction(i。e。,thermal,electrochemical，photochemical，nuclear).Morecommonbreakdownsareaccordingtothetypesofvesselsandflowsthatexist。反應(yīng)器可以用許多方法分類,各自適用于特定的目的。例如，Henglein（1969)基于用于產(chǎn)生反應(yīng)的能量來源，即，熱量，電化學(xué)，光化學(xué)，原子核,選擇了一種細(xì)目分類。更多普通的細(xì)目分類是按照所存在的容器和流量的類型。BatchReactors1。間歇反應(yīng)器Thebatchreactor（BR)isthealmostuniversalchoiceinthechemist’slaboratorywheremostchemicalprocessesoriginate。Thereasonisthesimplicityandversatilityofthebatchreactor，whetheritbeatesttube,athree—neckflask，anautoclave，oracellinaspectroscopicinstrument.Regardlessoftherateofthereaction,theseareclearlylowproductionratedevices。Asscaleupisdesired，themoststraightforwardapproachistomovetoalargerbatchreactorsuchasalargevatortank.間歇反應(yīng)器在化學(xué)實(shí)驗(yàn)室?guī)缀跏且话愕倪x擇,大多數(shù)的化學(xué)過程在那里產(chǎn)生。間歇反應(yīng)器的原理具簡單性和通用性，不管它是一支試管，一個(gè)三頸瓶，一個(gè)高壓釜，還是一個(gè)光譜儀器的比色皿。不管反應(yīng)比例，很清楚這些是低產(chǎn)率設(shè)備。當(dāng)要求放大反應(yīng)器時(shí)，大多直截了當(dāng)?shù)耐緩绞且浦烈粋€(gè)較大的間歇反應(yīng)器如一個(gè)較大的大桶或罐。Commercialbatchreactorscanbehuge,100000galormore。Thecycletime,oftenadayormore,typicallybecomeslongerasreactorvolumeincreasesinordertoachieveasubstantialproductionratewithaninherentlyslowreaction。Fabrication，shipping，orotherfactorsplacealimitthesizeofabatchreactor.Forexample，transportationcapacitycanlimitthesizeofabatchreactorforwhichshop,asopposedtoon—site，fabricationoftheheatexchangesurfaceisrequired。Thislimitstheproductionratesforwhichbatchreactorsmaybeeconomicallyutilized.Also,batchreactorsmustbefilled，emptied,andcleaned。Forfastreactionstheseunproductiveoperationsconsumefarmoretimethanthereactionitselfandcontinuousprocessescanbecomemoreattractive。商業(yè)化的間歇反應(yīng)器是龐大的，10萬加侖或更大.對于慢化學(xué)反應(yīng),為提高生產(chǎn)率必須增加反應(yīng)器體積,而這往往導(dǎo)致反應(yīng)器的循環(huán)周期變長，常常以天計(jì)算。制造、運(yùn)輸以及其他因素限制了反應(yīng)器的規(guī)模，如熱傳遞能力會限制間歇反應(yīng)器的尺寸,熱交換器必須在制造廠而不是在現(xiàn)場加工。這限制了產(chǎn)率由于這間歇反應(yīng)器可以被經(jīng)濟(jì)地利用。間歇反應(yīng)器也必須裝料、卸料和清洗.為了加快反應(yīng)這些非生產(chǎn)性的操作消耗了多于反應(yīng)本身的時(shí)間，連續(xù)化過程可能更有吸引力。2.SemibatchReactors(SBR）2.半間歇反應(yīng)器Somereactionsmayyieldaproductinadifferentphasefromthereactionmixture.Exampleswouldbeliberationofagasfromaliquid-phasereactionortheformationofaprecipitateinafluid-phasereaction.Todrivethereactiontocompletion,itmaybedesirabletocontinuouslyseparatetherawproductphase。Asemibatchoperationmayresultaswellfromdifferingmodesoffeedingtheindividualreactants。Forreasonswewilldiscusslater，itmaybedesirabletochargeonereactanttothereactorattheoutsetandbleedasecondreactantincontinuouslyovertime。Suchreactorshavebothabatchandaflowcharacterand，likebatchreactors,areusefulforslowreactionsandlowproductionrates.一些反應(yīng)器可以從反應(yīng)混合物的不同相態(tài)中生產(chǎn)出某種產(chǎn)品.例如液相反應(yīng)中氣體的釋放,或流動相反應(yīng)中沉淀的生成.為了驅(qū)使反應(yīng)完全，希望繼續(xù)分離粗產(chǎn)物相。個(gè)別反應(yīng)物的不同加入方式也導(dǎo)致半連續(xù)操作。原因我們以后討論，可希望一開始加入一種反應(yīng)物以后連續(xù)加入第二種反應(yīng)物。這類反應(yīng)器同時(shí)具有一個(gè)間歇和一個(gè)流動的特征，像間歇反應(yīng)器，適用于慢反應(yīng)和低產(chǎn)率.3。ContinuousStirredTankReactors(CSTR)3。連續(xù)流動攪拌反應(yīng)器ItisasmallstepfromthebatchreactortotheCSTR.Thesamestirredvesselmaybeusedwithonlytheadditionofpipingandstoragetankstoprovideforthecontinuousin-andoutflow.Fasterreactionscanbeaccommodatedandlargerproductionratescanbeachievedbecauseoftheuninterruptedoperation。CSTRsaremostoftenusedforliquid-phasereactions,suchasnitrationandhydrolysis,andmultiphasereactionsinvolvingliquidwithgasesand/orsolids.Exampleswouldbechlorinationandhydrogenation。從間歇反應(yīng)器到連續(xù)流動攪拌反應(yīng)器是小小的一步。同樣的攪拌式容器的使用可僅僅添加管道和儲罐以提供連續(xù)進(jìn)料和出料。因?yàn)檫B續(xù)操作可加快反應(yīng)并提高產(chǎn)率。通常大多數(shù)連續(xù)流動攪拌反應(yīng)器用于液相反應(yīng)，例如硝化和水解,多相反應(yīng)器涉及液—?dú)夂?或液-固.例如氯化和加氫.4。CSTRinSeries4.多級串聯(lián)連續(xù)流動攪拌反應(yīng)器ItwasshownthatconsiderablegainsinproductionrateandeconomicscanbeachievedbypassingthereactingmixturethroughaseriesofCSTRs.Again，weseehoweasyitistoachieveagradualscaleup，sayforaspecialtychemicalforwhichisincreasing。CSTRsinseriesareusuallyusedforliquid—phasereactions.事實(shí)證明通過一系列多級串聯(lián)連續(xù)流動攪拌反應(yīng)器的混合能夠獲得高產(chǎn)率和重大的經(jīng)濟(jì)效益。再者，這種反應(yīng)器容易放大，例如某種化學(xué)品的需求逐步增加時(shí)常這樣做。多級串聯(lián)連續(xù)流動攪拌反應(yīng)器通常用于液相反應(yīng).5.TubularReactors5.管式反應(yīng)器Astheproductionraterequirementincreases，batteriesofCSTRsbecomeincreasinglycomplexandtubularreactorsbecomeattractive。Withthetransitiontotubularreactors，someversatilityislostandmoreprocessintegrationisrequired。Nevertheless,tubularreactorsfindextensiveapplicationinliquid—phasereactions，forexample,polymerization,andarealmostalwaysthecontinuousreactorofchoiceforgas—phasereactions,forexample，pyrolysis.Exceedinglyhighproductionratescanbeachievedwithtubularreactorseitherbyincreasingthediameterofthetubeormorecommonlybyusingasufficientnumberoftubesinparallel.當(dāng)產(chǎn)率需要增加時(shí)，增加許多套連續(xù)攪拌式反應(yīng)器變得復(fù)雜,而管式反應(yīng)器變得誘人。轉(zhuǎn)化成管式反應(yīng)器失去了一些通用性并要求綜合許多操作.盡管如此，管式反應(yīng)器在液相反應(yīng)中起著廣泛作用,例如，聚合反應(yīng),氣-液反應(yīng)幾乎總是選擇連續(xù)反應(yīng)器,例如，高溫裂解。采用管式反應(yīng)器能夠獲得非常高的產(chǎn)率,要么增加管的直徑要么通過使用充足數(shù)量的并列管提高更大的通用性。6。Recyclereactors6。循環(huán)反應(yīng)器Recyclereactorcanbebatch,CSTR,tubular,andsooninnaturewiththepurposeoftherecyclevaryingfromonecasetothenext.Manylarge-scalecommercialprocessesincorporatetherecycleofoneormorestreamsbacktoanearlierpointintheprocesstoconserverawmaterials。Thispracticeoftenresultsintheaccumulationofimpurities,whichinturnrequiresseparation.Usuallyitisnotsimplythereactoroutletstreamthatisrecycledbacktothereactorinlet,butitcanbe.Forexampleinabatchreactorthereactingmixturecanberecycled，orpumpedaround，throughaheatexchangertoprovidethermalcontrol.循環(huán)反應(yīng)器出于從一種情況到下一種情況循環(huán)變化的目的,在種類上可以是間歇反應(yīng)器、連續(xù)流動攪拌反應(yīng)器、管式反應(yīng)器等等?；氐捷^早的觀點(diǎn)，在節(jié)省粗原料的過程中，許多大規(guī)模的商業(yè)操作合并了一個(gè)或多個(gè)循環(huán)。這一實(shí)踐通常導(dǎo)致了雜質(zhì)的累積，它們依次需要分離.通常不是簡單地將反應(yīng)器的出料返回到入口，當(dāng)然也可以這樣做。例如,在間歇反應(yīng)器中反應(yīng)混合物可以回收，或用泵打循環(huán)，通過熱交換器控制熱。Recyclereactorhavealsofoundvaluableapplicationinthelaboratoryandpilotplantbecauseoftheirspecialcharacteristics。Atoneextreme，inwhichalloftheproductisrecycled(nonetflow),thereactoristheexactequivalentofthewell-stirredbatchreactor.Attheotherextremeofnorecycle,thereactorissimplythetubularvariety.Ifthereissomenetflowbuttherecyclerateishigh，theoverallreactorperformslikeaCSTR。Yetthereactiontubeitselfbehaveslikedifferentialtubularreactor。Thisversatilityoftherecyclereactorcanbeexploitedtogreatadvantageinresearchanddevelopment。循環(huán)反應(yīng)器由于其特殊的特性在實(shí)驗(yàn)室和中試車間也發(fā)現(xiàn)了應(yīng)用價(jià)值。一個(gè)極端是將所有的產(chǎn)物循環(huán)（沒有凈的流出），此時(shí)循環(huán)反應(yīng)器嚴(yán)格等效于全混間歇反應(yīng)器。另一個(gè)極端是沒有循環(huán),反應(yīng)器是簡單的管式類。假如有一些凈的流出但循環(huán)率很高，所有的反應(yīng)器運(yùn)行類似于連續(xù)流動攪拌反應(yīng)器。然而反應(yīng)器本身的類似于不同的管式反應(yīng)器。在研究和發(fā)展中循環(huán)反應(yīng)器的通用性能夠開發(fā)出更大的優(yōu)點(diǎn)(勢）。-—BisioA.，KabelRL。ScaleupofChemicalProcesses.NewYork:JohnWiley＆SonsInc.,1985。255~257T14Styrene-ButadieneCopolymer第十四單元丁二烯—苯乙烯共聚物Thesyntheticrubberindustry，basedonthefree—radicalemulsionprocess,wascreatedalmostovernightduringWorldWarII.Styrene-butadiene（GR—S)rubbercratedatthattimegivessuchgoodtiretreadsthatnaturalrubberhasneverregainedthismarket。合成橡膠工業(yè)，以自由基乳液過程為基礎(chǔ),在第二次世界大戰(zhàn)期間幾乎很快地形成。那時(shí),丁苯橡膠制造的輪胎性能相當(dāng)優(yōu)越,使天然橡膠在市場黯然失色.TheGR—Sstandardrecipeis丁苯橡膠的標(biāo)準(zhǔn)制法是組分重量分?jǐn)?shù)組分重量分?jǐn)?shù)丁二烯72過硫酸鉀0.3苯乙烯25肥皂片5.0十二烷基硫醇0。5水180Thismixtureisheatedwithstirringandat50℃givesconversionsof5％～6%perhour。Polymerizationisterminatedat70％~75％conversionbyadditionofa“short—stop”,suchashydroquinone(approximately0。1part）,toquenchradicalsandpreventexcessivebranchingandmicrogelformation.Unreactedbutadieneisremovedbyflashdistillation，andsyrenebysteam—strippinginacolumn。Afteradditionofanantioxidant，suchasN-phenyl-β—混合物在攪拌下50℃加熱，每小時(shí)轉(zhuǎn)化5%～6%,在轉(zhuǎn)化率達(dá)70%～75％時(shí)通過加入“終止劑"聚合反應(yīng)終止，例如對苯二酚（大約0。1的重量百分含量），抑制自由基并避免過量支化和微凝膠形成。未反應(yīng)的丁二烯通過閃蒸去除，苯乙烯在萃取塔中通過蒸汽萃?。▌冸x）。在加入抗氧劑后，例如N-甲基-β—萘胺（1.25的重量百分含量）,加入鹽水,其次加入稀釋的硫酸或硫酸鋁后乳液凝膠。凝膠碎片被洗滌、干燥并包裝裝運(yùn)。Fig。14。1SBRplantflowdiagramCourtesyofHydrocarbonProcessingandPetroleumRefiner。圖14.1丁苯橡膠廠流程圖取自烴類加工和石油產(chǎn)品精制Thisprocedureisstillthebasisforemulsionpolymerizationtoday.AnimportantimprovementiscontinuousprocessingillustratedinFig.14.1；computermodelinghasalsobeendescribed.今天這種生產(chǎn)過程仍是膠體聚合反應(yīng)的基礎(chǔ)。如圖14。1所示一個(gè)重要的進(jìn)步是連續(xù)操作；也采用計(jì)算機(jī)模型描述.Inthecontinuousprocess,styrene,butadiene,soap，initiator，andactivator(anauxiliaryinitiatingagent）arepumpedcontinuouslyformstoragetanksthroughaseriesofagitatedreactorsatsucharatethatthedesireddegreeofconversionisreachedatthelastreactor.Shortstopisadded,thelatexwarmedwithsteam，andtheunreactedbutadieneflashedoff.Excessstyreneissteam-stripped,andthelatexfinishedasshowninFig。14。1.在連續(xù)操作中,苯乙烯、丁二烯、肥皂、引發(fā)劑和活化劑（一種助引發(fā)劑）用泵從儲罐通過一系列的混合反應(yīng)器，泵送流率根據(jù)末釜的轉(zhuǎn)化率控制.加入終止劑，乳液用蒸氣加熱，未反應(yīng)的丁二烯被閃蒸.剩余的苯乙烯被蒸氣剝離，如圖14。1表示乳液完成。表14.1冷丁苯膠的典型配方組分配方1配方2丁二烯7271苯乙烯2829特十二烷基硫醇0.20.18過氧化二異丙苯0。08過氧化薄荷烷0.08硫酸亞鐵七水合物0.140。03焦磷酸鉀0.18磷酸鈉十水合物0。5乙二胺四乙酸鈉0.035甲醛次硫酸鈉0。08松香酸4.04。5水180200SBRpreparedfromtheoriginalGR-Srecipeisoftenc