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1、高分子專業(yè)英語(yǔ)課文翻譯高分子專業(yè)英語(yǔ)選講課文翻譯資料A高分子化學(xué)和高分子物理UNIT 1 What are Polymer?第一單元什么是高聚物,What are polymers? For one thing, they are complex and giant molecules and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are different from low molecular weight compounds like, say, common salt. To如說普通的鹽。contrast the difference, the molecul

2、ar weight of common salt is onlywhile與低分子化合物不同的是,普通鹽的分子量?jī)H僅是58.5,that of a polymer can be as high as several hundred thousand, evenmore than thousand 而高聚物的分子量高于105,甚至大于106。thousands . These big molecules or macro- molecules are made up of much smaller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,molecules, can be

3、 of one or more chemical compounds. To illustrate,imagine that大分子能夠是一種或多種化合物。舉例說明,a set of rings has the same size and is made of the same material.When these things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areinterlinked, the chain formed can be considered as representing apolymer from 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

4、高聚 物。molecules of the same compound. Alternatively, individual ringscould be of另一方面,獨(dú)特的環(huán)可以大小不同、材料不同,different sizes and materials, and interlinked to represent apolymer from相連接后形成具有不同分子量化合物組成的聚合物。molecules of different compounds.This interlinking of many units has given the polymer its name, polymea

5、ning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)”,many and mer meaning part (in Greek). As an example, agaseous compoundmer意味著“鏈節(jié)、基體”(希臘語(yǔ)中)。例如:稱為丁二烯的氣態(tài)化合物,called butadiene, with a molecular weight of 54, combines nearly4000 times and 分子量為54,化合將近4000次,gives a polymer known as polybutadiene (a synthetic rubber) w

6、ithabout 200得到分子量大約為200000被稱作聚丁二烯(合成橡膠)的高聚物。0高分子專業(yè)英語(yǔ)選講課文翻譯資料000molecular weight. The low molecular weight compounds from whichthe polymers形成高聚物的低分子化合物稱為單體form are known as monomers. The picture is simply as follows:下面簡(jiǎn)單地描述一下形成過程:butadiene + butadiene + ? + butadiene-?polybutadiene(4 000 time)丁二烯,丁二烯

7、,,丁二烯一一?聚丁二烯4000次)(One can thus see how a substance (monomer) with as small a molecule weight因而能夠看到分子量?jī)H為54的小分子物質(zhì)(單體)as 54 grow to becom e a giant molecule (polymer) of (54 x 4 000?)200 000 molecular如何逐漸形成分子量為200000的大分子(高聚物)。weight. It is essentially the giantness of the size of thepolymer molecule實(shí)質(zhì)

8、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 that makesits behavior different from that of a commonly known chemical compound 合物。such as benzene. Solid benzene, for instance, melts to become liquid benzene at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。5.5? and , on further heating, boils into gaseous benzene. As against

9、this與這類簡(jiǎn)單化合物well-defined behavior of a simple chemical compound, a polymer likepolyethylene 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does not melt sharply at one particular temperature into cleanliquid. Instead, 體。it becomes increasingly softer and, ultimately, turns into a veryviscous, tacky而聚合物變得越來越

10、軟,最終,變成十分粘稠的聚合物熔融體。molten mass. Further heating of this hot, viscous, molten polymer does convert將這種熱而粘稠的聚合物熔融體進(jìn)一步加熱,會(huì)轉(zhuǎn)變成各種氣體,it into various gases but it is no longer polyethylene. (Fig. 1.1).但它不再是聚乙烯(如圖1.1)。固態(tài)苯一一?液態(tài)苯一一?氣態(tài)苯1高分子專業(yè)英語(yǔ)選講課文翻譯資料加熱,5.5?加熱,80?固體聚乙烯一一?熔化的聚乙烯一一?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

11、)和聚合物(聚乙烯)受熱后的不同行為Another striking difference with respect to the behavior of apolymer and that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。of a low molecular weight compound concerns the dissolution process.Let us take,for example, sodium chloride and add it slowly to s fixed quantityof water. The例如,讓我們研究一下,將氯化鈉

12、慢慢地添加到固定量的水中。salt, which represents a low molecular weight compound, dissolves in water up to 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,s point (called saturation point) but, thereafter, any further quantity added does但,此后,進(jìn)一步添加鹽不進(jìn)入溶液中卻沉到底部而not go into solution but settles at the bottom and just remains there a

13、s solid.保持原有的固體狀態(tài)。The viscosity of the saturated salt solution is not very much different from that飽和鹽溶液的粘度與水的粘度不是十分不同。of water. But if we take a polymer instead, say, polyvinyl alcohol, and add it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to a fixed quantity of water, the polymer does not go into solution i

14、mmediately.合物不是馬上進(jìn)入到溶液中。The globules of polyvinyl alcohol first absorb water, swell and get distorted in聚乙烯醇顆粒首先吸水溶脹,發(fā)生形變,經(jīng)過很長(zhǎng)的時(shí)間以后進(jìn)入到溶液中。shape and after a long time go into solution. Also, we can add a very large quantity同樣地,我們可以將大量的聚合物加入到of the polymer to the same quantity of water without the sat

15、uration point ever 同樣量的水中,不存在飽和點(diǎn)。being reached. As more and more quantity of polymer is added to water, the time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2高分子專業(yè)英語(yǔ)選講課文翻譯資料taken for the dissolution of the polymer obviously increases and themix ultimately終呈現(xiàn)柔軟像面團(tuán)一樣粘稠的混合物。assumes a soft, dough-like consistency. An

16、other peculiarity is that,in water,另一個(gè)特點(diǎn)是,在水中聚乙烯醇不會(huì)像過量polyvinyl alcohol never retains its original powdery nature as theexcess sodium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)。chloride does in a saturated salt solution. In conclusion, we cansay that (1)總之,我們可以講(1)聚乙烯醇的溶the long time taken by polyvinyl alcohol for dis

17、solution, (2) theabsence of a解需要很長(zhǎng)時(shí)間,(2)不存在飽和點(diǎn),saturation point, and (3) the increase in the viscosity are all characteristics(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of a typical polymer being dissolved in a solvent and these characteristics are歸因于聚合物大分子的尺寸。attributed mainly to the large molecular size of the

18、polymer. The behavior of alow molecular weight compound and that of a polymer on dissolution are illustrated 如圖1.2說明了低分子量化合物和聚合物的溶解行為。in Fig.1.2.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恼扯纫灰??形成飽和溶?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氯乙烯醇碎片加入到水中一一?碎片開始?脹一一?碎片慢慢地進(jìn)入到溶液中允許維持現(xiàn)狀充分?jǐn)嚢枰灰??形成粘稠的聚合物溶?溶液粘度十分高于水的粘度繼續(xù)攪拌聚

19、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Gowariker VR, Viswanathan N V, Sreedhar J. Polymer Science. NewYork:3高分子專業(yè)英語(yǔ)選講課文翻譯資料John Wiley & Sons, 1986.6UNIT 2 Chain Polymerization第二單元鏈?zhǔn)骄酆戏磻?yīng)Many olefinic and vinyl unsaturated compounds are able to formchain-OlikeStaudinger第一個(gè)發(fā)現(xiàn)一例現(xiàn)象,許多烯姓:和不飽和烯姓;通過打開雙鍵可macr

20、omolecules through elimination of the double bond, a phenomenonfirst 以形成鏈?zhǔn)酱蠓肿?。recognized by Staudinger. Diolefins polymerize in the same manner, however, only二烯姓:以同樣的方式聚合,然而,僅限于兩個(gè)雙鍵中one of the two double bonds is eliminated. Such reactions occurthrough the initial的一個(gè)。這類反應(yīng)是通過單體分子首先加成到引addition of a m

21、onomer molecule to an initiator radical or aninitiator ion, by 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which the active state is transferred from the initiator to the added monomer.力口成的單體上。In the same way by means of a chain reaction, one monomer molecule after the other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200

22、0,is added (200020000 monomers per second) until the active state is terminated 20000 個(gè)單體)直到活性中心通過不同的反應(yīng)類型而終止。through a different type of reaction. The polymerization is a chain reaction in聚合反應(yīng)是鏈?zhǔn)椒磻?yīng)的原因有兩種:two ways: because of the reaction kinetic and because as a reaction product one因?yàn)榉磻?yīng)動(dòng)力學(xué)和因?yàn)樽鳛榉磻?yīng)產(chǎn)物它

23、是一種鏈?zhǔn)椒肿?。鏈分子的長(zhǎng)度與動(dòng)力obtains a chain molecule. The length of the chain molecule isproportional to the學(xué)鏈長(zhǎng)成正 比。kinetic chain length.One can summarize the process as follow (R. is equal to theinitiator radical):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)ne thus obtains polyvinylchloride from vinylchloride, orpolystyrene

24、 from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4高分子專業(yè)英語(yǔ)選講課文翻譯資料styrene, or polyethylene from ethylene, etc.獲得聚乙烯,等等。The length of the chain molecules, measured by means of the degreeof借助于聚合度估算的分子鏈長(zhǎng),在一個(gè)大范圍內(nèi)可以通過選擇適宜的反應(yīng)polymerization, can be varied over a large range through selectionof suitable條件被改變。reaction

25、conditions. Usually, with commercially prepared andutilized polymers,通常,通過大量地制備和利用聚合物,聚合度在1000,the degree of polymerization lies in the range of 1000 to 5000, butin many cases 5000 范圍內(nèi),但在許多情況下可低于500、高于10000。it can be below 500 and over 10000. This should not be interpreted to mean that這不應(yīng)該把所有聚合物材料的分

26、子量理解all molecules of a certain polymeric material consist of 500, or1000, or 5000 為由500,或1000,或5000個(gè)單體單元組成。monomer units. In almost all cases, the polymeric material consists of a mixture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。of polymer molecules of different degrees of polymerization.Polymerization, a c

27、hain reaction, occurs according to the same mechanism as聚合反應(yīng),鏈?zhǔn)椒磻?yīng),依照與眾所周知的氯(氣)-氫(氣)反應(yīng)和光氣的分解機(jī)理進(jìn)行。the well-known chlorine-hydrogen reaction and the decomposition of phosegene.The initiation reaction, which is the activation process of the double bond,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。can be brought abou

28、t by heating, irradiation, ultrasonics, or initiators. Theinitiation of the chain reaction can be observed most clearly withradical or ionic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。initiators. These are energy-rich compounds which can add suitableunsaturated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compounds (monomers)

29、and maintain the activated radical, or ionic,state so that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。further monomer molecules can be added in the same manner. For theindividual steps5高分子專業(yè)英語(yǔ)選講課文翻譯資料of the growth reaction one needs only a relatively small activationenergy and對(duì)于增長(zhǎng)反應(yīng)的各個(gè)步驟,每一步僅需要相當(dāng)少的活化能,therefore throu

30、gh a single activation step (the actual initiationreaction) a large因此通過一步簡(jiǎn)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,number of olefin molecules are converted, as is implied by the term“chain這正如連鎖反應(yīng)這個(gè)術(shù)語(yǔ)的內(nèi)涵那樣。reaction ” . Because very small amounts of the initiator bring aboutthe formation因?yàn)樯倭康囊l(fā)劑引發(fā)形成大量的聚合物原料(1:1

31、000,1:10000),of a large amount of polymeric material (1:1000 to 1:1000), it ispossible to regard從表面上看聚合反應(yīng)很polymerization from a superficial point of view as a catalyticreaction. For this可能是催化反應(yīng)。reason, the initiators used in polymerization reactions are oftendesignated as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)

32、劑,polymerization catalysts, even though, in the strictest sense, theyare not true但是,嚴(yán)格地講它們不是真正意義上的催化劑,catalysts because the polymerization initiator enters into thereaction as a real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partner and can be found chemically bound in the reactionproduct ,i.e. ,the以在反應(yīng)產(chǎn)物,既聚合物的末端發(fā)現(xiàn)

33、。polymer, In addition to the ionic and radical initiators there arenow metal complex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initiators (which can be obtained, for example, by the reaction of titanium(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),tetrachloride or titanium trichloride with aluminum alkyls), whichplay an Z引發(fā)劑在聚合反應(yīng)中起到了重

34、要作用,important role in polymerization reactions (Ziegler catalysts) ,Themechanism of their catalytic action is not yet completely clear.它們催化活動(dòng)的機(jī)理還不是十分清楚。高分子專業(yè)英語(yǔ)選講課文翻譯資料UNIT 3 Step-Growth Polymerization第三單元逐步聚合Many different chemical reactions may be used to synthesizepolymeric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

35、。materials by step-growth polymerization. These includeesterification, amidation,這些反應(yīng)包括酯化、酰胺化、氨基甲酸t(yī)he formation of urethanes, aromatic substitution, etc.Polymerization proceeds 酯、芳香族取代物的形成等。by the reactions between two different functional groups, e.g.,hydroxyl and通過反應(yīng)聚合反應(yīng)在兩種不同的官能團(tuán),如,羥基和竣基,或異鼠酸酯和羥基之

36、間。carboxyl groups, or isocyanate and hydroxyl groups.All step-growth polymerization fall into two groups depending on thetype of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。monomer(s) employed. The first involves two different polyfunctional monomers in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)。which each monomer possesses only one

37、 type of functional group. A polyfunctional monomer is one with two or more functional groups permolecule. The second involves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)。a single monomer containing both types of functional groups. Thesynthesis of第二類涉及含有兩類官能團(tuán)的單種單體。polyamides 川ustrates both groups of polymerization reactio

38、ns. Thus, polyamides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can be obtained from the reaction of diamines with diacids酸的反應(yīng)或氨基酸之間的反應(yīng)得到。元胺和二元nH2N-R-NH2+nHO2R- -CO2H?H-(-NH-R-NHCOR -CO-)n-OH+(2n-1)H2O (3.1)or from the reaction of amino acids with themselvesnH2R-CO2H? H-(-NH-R-CO-)n-OH+(n-1)H20 (3.2)The two groups

39、 of reactions can be represented in a general mannerby the equations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as followsA+B-B ? - -A-A-B-B-A-B?- -A-B-反應(yīng)式略7高分子專業(yè)英語(yǔ)選講課文翻譯資料Reaction (3.1) illustrates the former, while (3.2) is of the lattertype.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(a)未反應(yīng)單體;(b)50%已反應(yīng);(c)83.3%已反應(yīng);(

40、d) 100%已反應(yīng)(虛線表示反應(yīng)種類)Polyesterification, whether between diol and dibasic acid orintermolecularly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。between hydroxy acid molecules, is an example of a step-growth polymerizationprocess. The esterification reaction occurs anywhere in the monomer matrix where酯化反應(yīng)出現(xiàn)在

41、單體本體中兩個(gè)單體分子相碰撞的位置,two monomer molecules collide, and once the ester has formed, it, too, can react且酯一旦形成,further by virtue of its still-reactive hydroxyl or carboxyl groups.The net effect依靠酯上仍有活性的羥基或竣基還可以進(jìn)一步進(jìn)行反應(yīng)。of this is that monomer molecules are consumed rapidly without anylarge increase酯化的結(jié)果是單體

42、分子很快地被消耗掉,而分子量卻沒有多少增加。in molecular weight. Fig. 3.1 川ustrates this phenomenon. Assume,for example,圖3.1說明了這個(gè)現(xiàn)象。that each square in Fig. 3.a represents a molecule of hydroxy acid.After the 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。initial dimmer molecules from (b), half the monomer molecules havebeen consumed (b)中的二聚

43、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。and the average degree of polymerization (DP) of polymeric speciesis 2. As trimer and more dimer molecules form (c), more than 80% of themonomer molecules have (c)中當(dāng)三聚體和更多的二聚體形成,大于80%勺單體分子已反應(yīng),但DP僅僅還是2.5。reacted (d), DP is 4. But each polymer molecule that forms still h

44、asreactive end (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;groups; hence the polymerization reaction will continue in astepwise fashion, 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with each esterification of monomers. Thus, molecular weightincreases slowly even8高分子專業(yè)英語(yǔ)選講課文翻譯資料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

45、體轉(zhuǎn)化率,at high levels of monomer conversion, and it will continue toincrease until the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)viscosity build-up makes it mechanically too difficult to removewater of 的端基。esterification or for reactive end groups to find each other.It can also be shown that in the A-A+B-B

46、 type of polymerization, an exact-A+B-B的聚合反應(yīng)中也可以看到,在Astoichiometric balance is necessary to achieve high molecularweights. If some精確的當(dāng)量平衡是獲得高分子量所必需的。monofunctional impurity is present, its reaction will limit themolecular weight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。by rendering a chain end inactive. Simil

47、arly, high-purity monomers are necessary同樣,在A-B類的縮聚反應(yīng)中高純度的單體是必要的,in the A-B type of polycondensation and it follows that high-yield reactions are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),the only practical ones for polymer formation, since side reactions will upset因?yàn)楦狈磻?yīng)會(huì)破壞當(dāng)量平衡。the stoichiometric balance.Stevens M P.

48、 Polymer Chemistry. London: Addison-WesleyPublishing Company, 1975. 13UNIT 4 Ionic Polymerization第四單元離子聚合反應(yīng)Ionic polymerization, similar to radial polymerization, also has the mechanism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of a chain reaction. The kinetics of ionic polymerization are

49、, however,但是,離子聚合的動(dòng)力學(xué)明顯地不同于自由基聚合反應(yīng)。considerably different from that of radical polymerization.The initiation reaction of ionic polymerization needs only a small(1)離子聚合的引發(fā)反應(yīng)僅需要很小的活化能。activation energy. Therefore, the rate of polymerization depends only slightly因此,聚合反應(yīng)的速率僅對(duì)溫度有較少的依賴性。9高分子專業(yè)英語(yǔ)選講課文翻譯資料on

50、 the temperature. Ionic polymerizations occur in many cases with explosive在許多情況下離子聚合猛烈地發(fā)生甚至低于50?violence even at temperature below 50?(for example, the anionic polymerization(例如,苯乙烯的陰離子聚合反應(yīng)在-70?在四氫味喃中,of styrene at - 70? in tetrahydrofuran, or the cationicpolymerization of或異丁烯的陽(yáng)離子聚合在-100?在液態(tài)乙烯中)。iso

51、butylene at - 100? in liquid ethylene ).With ionic polymerization there is no compulsory chain termination(2)對(duì)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,through recombination, because the growing chains can not react with each other.因?yàn)樯L(zhǎng)鏈之間不能發(fā)生鏈終止。Chain termination takes place only through impurities, or throughth

52、e addition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、of certain compounds such as water, alcohols, acids, amines, oroxygen, and in 酸、胺或氧這樣的化合物進(jìn)行加成而發(fā)生,general through compounds which can react with polymerization ionsunder the 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formation of neutral compounds or inactive i

53、onic species. If theinitiators are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,only partly dissociated, the initiation reaction is an equilibriumreaction, where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(chǎng)合,reaction in one direction gives rise to chain initiation and in theother direction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)。to chain

54、termination.In general ionic polymerization polymerization can be initiatedthrough acidic通常離子聚合反應(yīng)能通過酸性或堿性化合物被引發(fā)。or basic compounds. For cationic polymerization, complexes of BF3,AlCl, TiCl, 34對(duì)于陽(yáng)離子聚合反應(yīng)來說,BF,AlCl,TiCl和SnCl 3344and SnCl with water, or alcohols, or tertiary oxonium salts have shown the

55、mselves 4與水、或乙醇,或叔洋鹽的絡(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。to be particularly active. The positive ions are the ones that cause chain10高分子專業(yè)英語(yǔ)選講課文翻譯資料initiation. For example:例如:(反應(yīng)略)三乙基硼氟酸烽However, also with HCl, HSO, and KHSO, one can initiate cationicpolymerization. 244然而,BF也可以與HCl、HS&口 KHS0I發(fā)陽(yáng)離子聚合反應(yīng)。3244Init

56、iators for anionic polymerization are alkali metals and theirorganic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,compounds, such as phenyllithium, butyllithium, phenyl sodium, and例如苯基鋰、丁基鋰和三苯甲基鋰,triphenylmethyl potassium, which are more or less stronglydissociated in它們?cè)诓煌娜軇┲谢蚨嗷蛏俚貜?qiáng)烈分解。different solvents. To this grou

57、p belong also the so called Alfincatalysts, which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are a mixture of sodium isopropylate, allyl sodium, and sodium chloride.化鈉的混合物。With BF (and isobutylene as the monomer), it was demonstrated that the 3BF為引發(fā)劑(異丁烯為單體),3polymerization is possible only in the presence

58、of traces of traces of water or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。alcohol. If one eliminates the trace of water, BF alone does notgive rise to 3如果消除痕量的水,單純的BF不會(huì)引發(fā)聚合反應(yīng)。3polymerization. Water or alcohols are necessary in order to allow the formation按照上述反應(yīng)為了能形成BF-絡(luò)合物和引發(fā)劑離子水或乙醇是必需的。3of the BF-complex and the init

59、iator cation according to the above reactions. 3However, one should not describe the water or the alcohol as a “cocatalyst ” .但是不應(yīng)將水或乙醇描述成“助催化劑”。Just as by radical polymerization, one can also prepare copolymers by ionic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,polymerization, for example, anionic copolymers of s

60、tyrene and butadiene, or例如,苯乙烯-丁二烯陰離子共聚物,11高分子專業(yè)英語(yǔ)選講課文翻譯資料cationic copolymers of isobutylene and styrene, or isobutylene andviny ethers,或異丁烯-苯乙烯陽(yáng)離子共聚物,或異丁烯-乙烯基醴共聚物,等等。etc. As has been described in detail with radical polymerization, one can正如對(duì)自由基型聚合已經(jīng)詳細(xì)描述過那樣,characterize each monomer pair by so-call

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