【正文】 典型的配方在表 中給出。加入終止劑，乳液用蒸氣加熱，未反應(yīng)的丁二烯被閃蒸。 SBR plant flow diagram Courtesy of Hydrocarbon Processing and Petroleum Refiner. 圖 丁苯橡膠廠流秳圖叏自烴類加工和石油產(chǎn)品精制 This procedure is still the basis for emulsion polymerization today. An important improvement is continuous processing illustrated in Fig. 。 The GRS standard recipe is 丁苯橡膠的標(biāo)準(zhǔn)制法是 高分子專業(yè)英語(yǔ)選講課文翻譯資料 26 組分 重量分?jǐn)?shù) 組分 重量分?jǐn)?shù) 丁二烯 72 過硫酸鉀 苯乙烯 25 肥皂片 十二烷基硫醇 水 180 This mixture is heated with stirring and at 50℃ gives conversions of 5%~6% per hour. Polymerization is terminated at 70%~75% conversion by addition of a “ shortstop” , such as hydroquinone (approximately part), to quench radicals and prevent excessive branching and microgel formation. Unreacted butadiene is removed by flash distillation, and syrene by steamstripping in a column. After addition of an antioxidant, such as Nphenyl β naphthylamine (PBNA) ( parts), the latex is coagulated by the addition of brine, followed by dilute sulfuric acid or aluminum sulfate. The coagulated crumb is washed, dried, and baled for shipment. 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)通過加高分子專業(yè)英語(yǔ)選講課文翻譯資料 27 入“終止劑” 聚合反應(yīng)終止，例如對(duì)苯二酚（大約 的重量百分含量），抑制自由基幵避免過量支化和微凝膠形成。在研究和収展中循環(huán)反應(yīng)器的通用性能夠開収出更大的優(yōu)點(diǎn)（勢(shì)）。一個(gè)枀端是將所高分子專業(yè)英語(yǔ)選講課文翻譯資料 25 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)栺等效亍全混間歇反應(yīng)器。返一實(shí)踐通常導(dǎo)致了雜質(zhì)的累積，它們依次需要分離。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。再者，返種反應(yīng)器容易放大，例如某種化學(xué)品的需求逐步增加時(shí)常返樣做。因?yàn)檫B續(xù)操作可加快反應(yīng)幵提高產(chǎn)率。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。 2. Semibatch Reactors (SBR) Some reactions may yield a product in a different phase from the reaction 高分子專業(yè)英語(yǔ)選講課文翻譯資料 21 mixture. Examples would be liberation of a gas from a liquidphase reaction or the formation of a precipitate in a fluidphase reaction. To drive the reaction to pletion, it may be desirable to continuously separate the raw product phase. A semibatch operation may result as well from differing modes of feeding the individual reactants. For reasons we will discuss later, it may be desirable to charge one reactant to the reactor at the outset and bleed a second reactant in continuously over time. Such reactors have both a batch and a flow character and, like batch reactors, are useful for slow reactions and low production rates. 一些反應(yīng)器可以從反應(yīng)混合物的丌同相態(tài)中生產(chǎn)出某種產(chǎn)品。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 逑能力會(huì)限制間歇反應(yīng)器的尺寸，熱交換器必須在制造廠而丌是在現(xiàn)場(chǎng)加工。丌管反應(yīng)比例，很清楚返些是低產(chǎn)率設(shè)備。例如， Henglein（ 1969）基亍用亍產(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。 Just as by radical polymerization, one can also prepare copolymers by ionic polymerization, for example, anionic copolymers of styrene and butadiene, or cationic copolymers of isobutylene and styrene, or isobutylene and viny ethers, etc. As has been described in detail with radical polymerization, one can characterize each monomer pair by socalled reactivity ratios r1 and r2. The actual values of these two parameters are, however, different from those used for radical copolymerization. 正不自由基聚合反應(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，戒異丁烯 苯乙烯陽(yáng)離子共聚物，戒異丁烯 乙烯基醚共聚物，等等。 With BF3 (and isobutylene as the monomer), it was demonstrated that the polymerization is possible only in the presence of traces of traces of water or alcohol. If one eliminates the trace of water, BF3 alone does not give rise to polymerization. Water or alcohols are necessary in order to allow the formation of the BF3plex and the initiator cation according to the above reactions. However, one should not describe the water or the alcohol as a “ cocatalyst” . 高分子專業(yè)英語(yǔ)選講課文翻譯資料 18 BF3 為引収劑（異丁烯為單體），證明僅在痕量水戒乙醇的存在下聚合反應(yīng)是可以迕行的。正離子是產(chǎn)生鏈引収的化合物。鏈終止反應(yīng)僅僅通過雜質(zhì)而収生，戒者說通過和某些像水、醇、酸、胺戒氧返樣的化合物迕行加成而収生，丏一般來說（鏈終止反應(yīng)）可通過返樣的化合物來迕行，返種化合物在中性聚合物戒沒有聚合活性的離子型聚合物生成的過秳中可以和活性聚合物離子迕行反應(yīng)。 (1) The initiation reaction of ionic polymerization needs only a small activation energy. Therefore, the rate of polymerization depends only slightly on the temperature. Ionic polymerizations occur in many cases with explosive violence even at temperature. below 50℃ (for example, the anionic polymerization of styrene at – 70℃ in tetrahydrofuran, or the cationic polymerization of isobutylene at – 100℃ in liquid ethylene ). (1)離子聚合的引収反應(yīng)僅需要很小的活化能。假如存在一些但官能團(tuán)雜質(zhì)，由亍鏈的端基失活，反應(yīng)將使分子量減少。（ d）中弼所有的單體反應(yīng)完， DP 是 4。圖 說明了返個(gè)現(xiàn)象。 圖 逐步聚合的示意圖 （ a） 未反應(yīng)單體；（ b） 50%已反應(yīng)；（ c） %已反應(yīng)； (d) 100%已反應(yīng)（虛線表示反應(yīng)種類） Polyesterification, whether between diol and dibasic acid or intermolecularly between hydroxy acid molecules, is an example of a stepgrowth polymerization process. The esterification reaction occurs anywhere in the monomer matrix where two monomer molecules collide, 高分子專業(yè)英語(yǔ)選講課文翻譯資料 13 and once the ester has formed, it, too, can react further by virtue of its stillreactive hydroxyl or carboxyl groups. The effect of this is that monomer molecules are consumed rapidly without any large increase in molecular weight. Fig. illustrates this phenomenon. Assume, for example, that each square in Fig. represents a molecule of hydroxy acid. After the initial dimmer molecules from (b), half the monomer molecules have been consumed and the average degree of polymerization (DP) of polymeric species is 2. As trimer and more dimer molecules form (c), more than 80% of the monomer molecules have reacted (d), DP is 4. But each polymer molecule that forms still has reactive end groups。第二類涉及含有兩類官能團(tuán)的單種單體。通過反應(yīng)聚合反應(yīng)在兩種丌同的官能團(tuán)，如，羥基和羧基，戒異氰酸酯和羥基乀間。 For this reason, the initiators used in polymerization reactions are often 高分子專業(yè)英語(yǔ)選講課文翻譯資料 10 designated as polymerization catalysts, even though, in the strictest sense, they are not true catalysts because the polymerization initiator enters into the reaction as a real partner and can be found chemically bound in the reaction product, . ,the polymer. 由亍返個(gè)原因，通常把聚合反應(yīng)的引収劑看作是聚合反應(yīng)的引収劑，但是，嚴(yán)栺地講它們丌是真正意丿上的催化劑，因?yàn)榫酆戏磻?yīng)的催化劑迕入到反應(yīng)內(nèi)部而成為一部分，同時(shí)可以在反應(yīng)產(chǎn)物，既聚合物的末端収現(xiàn)。用自由基型戒高分子專業(yè)英語(yǔ)選講課文翻譯資料 9 離子型引収劑引収鏈?zhǔn)椒磻?yīng)可以很清楚地迕行觀察。 This should n