高分子材料与工程专业英语翻译

精品文档 0欢迎下载 A 高分子化学和高分子物理 UNIT 1 What are Polymer 第一单元 什么是高聚物 What are polymers For one thing they are complex and giant molecules and are different from low molecular weight compounds like say common salt To contrast the difference the molecular weight of common salt is only 58 5 while that of a polymer can be as high as several hundred thousand even more than thousand thousands These big molecules or macro molecules are made up of much smaller molecules can be of one or more chemical compounds To illustrate imagine that a set of rings has the same size and is made of the same material When these things are interlinked the chain formed can be considered as representing a polymer from molecules of the same compound Alternatively individual rings could be of different sizes and materials and interlinked to represent a polymer from molecules of different compounds 什么是高聚物 首先 他们是合成物和大分子 而且不同于低分子化合物 譬如说普通的盐 与低 分子化合物不同的是 普通盐的分子量仅仅是 58 5 而高聚物的分子量高于 105 甚至大于 106 这些 大分子或 高分子 由许多小分子组成 小分子相互结合形成大分子 大分子能够是一种或多种化合物 举例说明 想象一组大小相同并由相同的材料制成的环 当这些环相互连接起来 可以把形成的链看成 是具有同种分子量化合物组成的高聚物 另一方面 独特的环可以大小不同 材料不同 相连接后形成 具有不同分子量化合物组成的聚合物 This interlinking of many units has given the polymer its name poly meaning many and mer meaning part in Greek As an example a gaseous compound called butadiene with a molecular weight of 54 combines nearly 4000 times and gives a polymer known as polybutadiene a synthetic rubber with about 200 000molecular weight The low molecular weight compounds from which the polymers form are known as monomers The picture is simply as follows 许多单元相连接给予了聚合物一个名称 poly 意味着 多 聚 重复 mer 意味着 链节 基体 希腊语中 例如 称为丁二烯的气态化合物 分子量为 54 化合将近 4000 次 得到分子量大约为 200000 被称作聚丁二烯 合成橡胶 的高聚物 形成高聚物的低分子化合物称为单体 下面简单地描述 一下形成过程 butadiene butadiene butadiene polybutadiene 4 000 time 丁二烯 丁二烯 丁二烯 聚丁二烯 4000 次 One can thus see how a substance monomer with as small a molecule weight as 54 grow to become a giant molecule polymer of 54 4 000 200 000 molecular weight It is essentially the giantness of the size of the polymer molecule that makes its behavior different from that of a commonly known chemical compound such as benzene Solid benzene for instance melts to become liquid benzene at 5 5 and on further heating boils into 精品文档 1欢迎下载 gaseous benzene As against this well defined behavior of a simple chemical compound a polymer like polyethylene does not melt sharply at one particular temperature into clean liquid Instead it becomes increasingly softer and ultimately turns into a very viscous tacky molten mass Further heating of this hot viscous molten polymer does convert it into various gases but it is no longer polyethylene Fig 1 1 因而能够看到分子量仅为 54 的小分子物质 单体 如何逐渐形成分子量为 200000 的大分子 高聚 物 实质上 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这样的一般化合物 例如 固 态苯 在 5 5 熔融成液态苯 进一步加热 煮沸成气态苯 与这类简单化合物明确的行为相比 像聚 乙烯这样的聚合物不能在某一特定的温度快速地熔融成纯净的液体 而聚合物变得越来越软 最终 变 成十分粘稠的聚合物熔融体 将这种热而粘稠的聚合物熔融体进一步加热 不会转变成各种气体 但它 不再是聚乙烯 如图 1 1 固态苯 液态苯 气态苯 加热 5 5 加热 80 固体聚乙烯 熔化的聚乙烯 各种分解产物 但不是聚乙烯 加热 加热 图 1 1 低分子量化合物 苯 和聚合物 聚乙烯 受热后的不同行为 Another striking difference with respect to the behavior of a polymer and that of a low molecular weight compound concerns the dissolution process Let us take for example sodium chloride and add it slowly to s fixed quantity of water The salt which represents a low molecular weight compound dissolves in water up to s point called saturation point but thereafter any further quantity added does not go into solution but settles at the bottom and just remains there as solid The viscosity of the saturated salt solution is not very much different from that of water But if we take a polymer instead say polyvinyl alcohol and add it to a fixed quantity of water the polymer does not go into solution immediately The globules of polyvinyl alcohol first absorb water swell and get distorted in shape and after a long time go into solution Also we can add a very large quantity of the polymer to the same quantity of water without the saturation point ever being reached As more and more quantity of polymer is added to water the time taken for the dissolution of the polymer obviously increases and the mix ultimately assumes a soft dough like consistency Another peculiarity is that in water polyvinyl alcohol never retains its original powdery nature as the excess sodium chloride does in a saturated salt solution In conclusion we can say that 1 the long time taken by polyvinyl alcohol for dissolution 2 the absence of a saturation point and 3 the increase in the viscosity are all characteristics of a typical polymer being dissolved in a solvent and these characteristics are attributed mainly to the large molecular size of the polymer The behavior of a low molecular weight compound and that of a polymer on dissolution are illustrated in Fig 1 2 发现另一种不同的聚合物行为和低分子量化合物行为是关于溶解过程 例如 让我们研究一下 将氯化钠慢慢地添加到固定量的水中 盐 代表一种低分子量化合物 在水中达到点 叫饱和点 溶解 精品文档 2欢迎下载 但 此后 进一步添加盐不进入溶液中却沉到底部而保持原有的固体状态 饱和盐溶液的粘度与水的粘 度不是十分不同 但是 如果我们用聚合物替代 譬如说 将聚乙烯醇添加到固定量的水中 聚合物不 是马上进入到溶液中 聚乙烯醇颗粒首先吸水溶胀 发生形变 经过很长的时间以后进入到溶液中 同 样地 我们可以将大量的聚合物加入到同样量的水中 不存在饱和点 将越来越多的聚合物加入水中 认为聚合物溶解的时间明显地增加 最终呈现柔软像面团一样粘稠的混合物 另一个特点是 在水中聚 乙烯醇不会像过量的氯化钠在饱和盐溶液中那样能保持其初始的粉末状态 总之 我们可以讲 1 聚 乙烯醇的溶解需要很长时间 2 不存在饱和点 3 粘度的增加是典型聚合物溶于溶液中的特性 这 些特性主要归因于聚合物大分子的尺寸 如图 1 2 说明了低分子量化合物和聚合物的溶解行为 氯化钠晶体加入到水中 晶体进入到溶液中 溶液的粘度不是十分不同于 充分搅拌 水的粘度 形成饱和溶液 剩余的晶体维持不溶解状态 加入更多的晶体并搅拌 氯化钠的溶解 聚乙烯醇碎片加入到水中 碎片开始溶胀 碎片慢慢地进入到溶液中 允许维持现状 充分搅拌 形成粘稠的聚合物溶液 溶液粘度十分高于水的粘度 继续搅拌 聚合物的溶解 图 1 2 低分子量化合物 氯化钠 和聚合物 聚乙烯醇 不同的溶解行为 Gowariker VR Viswanathan N V Sreedhar J Polymer Science New York John Wiley hence the polymerization reaction will continue in a stepwise fashion with each esterification of monomers Thus molecular weight increases slowly even at high levels of monomer conversion and it will continue to increase until the viscosity build up makes it mechanically too difficult to remove water of esterification or for reactive end groups to find each other 聚酯化 是否在二元酸和二元醇或羟基酸分子间进行 是逐步聚合反应过程的一个例子 酯化反 应出现在单体本体中两个单体分子相碰撞的位置 且酯一旦形成 依靠酯上仍有活性的羟基或羧基还可 以进一步进行反应 酯化的结果是单体分子很快地被消耗掉 而分子量却没有多少增加 图 3 1 说明了 这个现象 例如 假定图 3 1 中的每一个方格代表一个羟基酸分子 b 中的二聚体分子 消耗二分之 一的单体分子聚合物种类的聚合度 DP 是 2 c 中当三聚体和更多的二聚体形成 大于 80 的单体 分子已反应 但 DP 仅仅还是 2 5 d 中当所有的单体反应完 DP 是 4 但形成的每一种聚合物分子还 有反应活性的端基 因此 聚合反应将以逐步的方式继续进行 其每一步酯化反应的反应速率和反应机 理均与初始单体的酯化作用相同 因此 分子量缓慢增加直至高水平的单体转化率 而且分子量将继续 增加直到粘度的增加使其难以除去酯化反应的水或难以找到相互反应的端基 It can also be shown that in the A A B B type of polymerization an exact stoichiometric balance is necessary to achieve high molecular weights If some monofunctional impurity is present its reaction will limit the molecular weight by rendering a chain end inactive Similarly high purity monomers are necessary in the A B type of polycondensation and it follows that high yield reactions are the only practical ones for polymer formation since side reactions will upset the stoichiometric balance 在 A A B B 的聚合反应中也可以看到 精确的当量平衡是获得高分子量所必需的 假如存在一些 但官能团杂质 由于链的端基失活 反应将使分子量减少 同样 在 A B 类的缩聚反应中高纯度的单体 是必要的 而且可以归结高收率的反应仅是形成聚合物的实际反应 因为副反应会破坏当量平衡 精品文档 6欢迎下载 Stevens M P Polymer Chemistry London Addison Wesley Publishing Company 1975 13 UNIT 4 Ionic Polymerization 第四单元 离子聚合反应 Ionic polymerization similar to radial polymerization also has the mechanism of a chain reaction The kinetics of ionic polymerization are however considerably different from that of radical polymerization 离子聚合反应 与自由基聚合反应相似 也有链反应的机理 但是 离子聚合的动力学明显地不 同于自由基聚合反应 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 离子聚合的引发反应仅需要很小的活化能 因此 聚合反应的速率仅对温度有较少的依赖性 在许多情况下离子聚合猛烈地发生甚至低于 50 例如 苯乙烯的阴离子聚合反应在 70 在四氢呋喃 中 或异丁烯的阳离子聚合在 100 在液态乙烯中 2 With ionic polymerization there is no compulsory chain termination through recombination because the growing chains can not react with each other Chain termination takes place only through impurities or through the addition of certain compounds such as water alcohols acids amines or oxygen and in general through compounds which can react with polymerization ions under the formation of neutral compounds or inactive ionic species If the initiators are only partly dissociated the initiation reaction is an equilibrium reaction where reaction in one direction gives rise to chain initiation and in the other direction to chain termination 2 对于离子聚合来说 不存在通过再结合反应而进行的强迫链终止 因为生长链之间不能发生 链终止 链终止反应仅仅通过杂质而发生 或者说通过和某些像水 醇 酸 胺或氧这样的化合物进行 加成而发生 且一般来说 链终止反应 可通过这样的化合物来进行 这种化合物在中性聚合物或没有 聚合活性的离子型聚合物生成的过程中可以和活性聚合物离子进行反应 如果引发剂仅仅部分地离解 引发反应即为一个平衡反应 在出现平衡反应的场合 在一个方向上进行链引发反应 而在另一个方向 上则发生链终止反应 In general ionic polymerization polymerization can be initiated through acidic or basic compounds For cationic polymerization complexes of BF3 AlCl3 TiCl4 and SnCl4 with water or alcohols or tertiary oxonium salts have shown themselves to be particularly active The positive ions are the ones that cause chain initiation For example 通常离子聚合反应能通过酸性或碱性化合物被引发 对于阳离子聚合反应来说 BF3 AlCl3 TiCl4 和 SnCl4与水 或乙醇 或叔烊盐的络合物提供了部分活性 正离子是产生链引发的化合物 例如 反 应略 三乙基硼氟酸烊 However also with HCl H2SO4 and KHSO4 one can initiate cationic polymerization 精品文档 7欢迎下载 Initiators for anionic polymerization are alkali metals and their organic compounds such as phenyllithium butyllithium phenyl sodium and triphenylmethyl potassium which are more or less strongly dissociated in different solvents To this group belong also the so called Alfin catalysts which are a mixture of sodium isopropylate allyl sodium and sodium chloride 然而 BF3也可以与 HCl H2SO4和 KHSO4引发阳离子聚合反应 阴离子聚合反应的引发剂是碱金属 和它们的有机金属化合物 例如苯基锂 丁基锂和三苯甲基锂 它们在不同的溶剂中或多或少地强烈分 解 所谓的 Alfin 催化剂就是属于这一类 这类催化剂是异丙醇钠 烯丙基钠和氯化钠的混合物 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 BF3 complex and the initiator cation according to the above reactions However one should not describe the water or the alcohol as a cocatalyst BF3为引发剂 异丁烯为单体 证明仅在痕量水或乙醇的存在下聚合反应是可以进行的 如果消 除痕量的水 单纯的 BF3不会引发聚合反应 按照上述反应为了能形成 BF3 络合物和引发剂离子水或乙 醇是必需的 但是不应将水或乙醇描述成 助催化剂 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 so called reactivity ratios r1 and r2 The actual values of these two parameters are however different from those used for radical copolymerization 正与自由基聚合反应一样 通过离子聚合反应也能制备共聚物 例如 苯乙烯 丁二烯阴离子共聚 物 或异丁烯 苯乙烯阳离子共聚物 或异丁烯 乙烯基醚共聚物 等等 正如对自由基型聚合已经详细 描述过那样 人们可以用所谓的竞聚率 r1和 r2来表征每单体对 然而 这两个参数的实际意义不同于 那些用于自由基共聚合反应的参数 Vollmert B Polymer Chemistry Berlin Sping Verlag 1973 163 PART B 聚合反应工程 UNIT 11 Reactor types 第十一单元 反应器类型 Reactors may be categorized in a variety of ways each appropriate to a particular perspective For example Henglein 1969 chooses a breakdown based on the source of energy used to initiate the reaction i e thermal electrochemical photochemical nuclear More common breakdowns are according to the types of vessels and flows that exist 反应器可以用许多方法分类 各自适用于特定的目的 例如 Henglein 1969 基于用于产生反 应的能量来源 即 热量 电化学 光化学 原子核 选择了一种细目分类 更多普通的细目分类是按 精品文档 8欢迎下载 照所存在的容器和流量的类型 1 Batch Reactors 1 间歇反应器 The batch reactor BR is the almost universal choice in the chemist s laboratory where most chemical processes originate The reason is the simplicity and versatility of the batch reactor whether it be a test tube a three neck flask an autoclave or a cell in a spectroscopic instrument Regardless of the rate of the reaction these are clearly low production rate devices As scale up is desired the most straightforward approach is to move to a larger batch reactor such as a large vat or tank 间歇反应器在化学实验室几乎是一般的选择 大多数的化学过程在那里产生 间歇反应器的原理具 简单性和通用性 不管它是一支试管 一个三颈瓶 一个高压釜 还是一个光谱仪器的比色皿 不管反 应比例 很清楚这些是低产率设备 当要求放大反应器时 大多直截了当的途径是移至一个较大的间歇 反应器如一个较大的大桶或罐 Commercial batch reactors can be huge 100 000 gal or more The cycle time often a day or more typically becomes longer as reactor volume increases in order to achieve a substantial production rate with an inherently slow reaction Fabrication shipping or other factors place a limit the size of a batch reactor For example transportation capacity can limit the size of a batch reactor for which shop as opposed to on site fabrication of the heat exchange surface is required This limits the production rates for which batch reactors may be economically utilized Also batch reactors must be filled emptied and cleaned For fast reactions these unproductive operations consume far more time than the reaction itself and continuous processes can become more attractive 商业化的间歇反应器是庞大的 10 万加仑或更大 对于慢化学反应 为提高生产率必须增加反应 器体积 而这往往导致反应器的循环周期变长 常常以天计算 制造 运输以及其他因素限制了反应器 的规模 如热传递能力会限制间歇反应器的尺寸 热交换器必须在制造厂而不是在现场加工 这限制了 产率由于这间歇反应器可以被经济地利用 间歇反应器也必须装料 卸料和清洗 为了加快反应这些非 生产性的操作消耗了多于反应本身的时间 连续化过程可能更有吸引力 2 Semibatch Reactors SBR 2 半间歇反应器 Some reactions may yield a product in a different phase from the reaction mixture Examples would be liberation of a gas from a liquid phase reaction or the formation of a precipitate in a fluid phase reaction To drive the reaction to completion 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 一些反应器可以从反应混合物的不同相态中生产出某种产品 例如液相反应中气体的释放 或流动 相反应中沉淀的生成 为了驱使反应完全 希望继续分离粗产物相 个别反应物的不同加入方式也导致 精品文档 9欢迎下载 半连续操作 原因我们以后讨论 可希望一开始加入一种反应物以后连续加入第二种反应物 这类反应 器同时具有一个间歇和一个流动的特征 像间歇反应器 适用于慢反应和低产率 3 Continuous Stirred Tank Reactors CSTR 3 连续流动搅拌反应器 It is a small step from the batch reactor to the CSTR The same stirred vessel may be used with only the addition of piping and storage tanks to provide for the continuous in and outflow Faster reactions can be accommodated and larger production rates can be achieved because of the uninterrupted operation CSTRs are most often used for liquid phase reactions such as nitration and hydrolysis and multiphase reactions involving liquid with gases and or solids Examples would be chlorination and hydrogenation 从间歇反应器到连续流动搅拌反应器是小小的一步 同样的搅拌式容器的使用可仅仅添加管道和 储罐以提供连续进料和出料 因为连续操作可加快反应并提高产率 通常大多数连续流动搅拌反应器用 于液相反应 例如硝化和水解 多相反应器涉及液 气和 或液 固 例如氯化和加氢 4 CSTR in Series 4 多级串联连续流动搅拌反应器 It was shown that considerable gains in production rate and economics can be achieved by passing the reacting mixture through a series of CSTRs Again we see how easy it is to achieve a gradual scale up say for a specialty chemical for which is increasing CSTRs in series are usually used for liquid phase reactions 事实证明通过一系列多级串联连续流动搅拌反应器的混合能够获得高产率和重大的经济效益 再者 这种反应器容易放大 例如某种化学品的需求逐步增加时常这样做 多级串联连续流动搅拌反应器通常 用于液相反应 5 Tubular Reactors 5 管式反应器 As the production rate requirement increases batteries of CSTRs become increasingly complex and tubular reactors become attractive With the transition to tubular reactors some versatility is lost and more process integration is required Nevertheless tubular reactors find extensive application in liquid phase reactions for example polymerization and are almost always the continuous reactor of choice for gas phase reactions for example pyrolysis Exceedingly high production rates can be achieved with tubular reactors either by increasing the diameter of the tube or more commonly by using a sufficient number of tubes in parallel 当产率需要增加时 增加许多套连续搅拌式反应器变得复杂 而管式反应器变得诱人 转化成管式 反应器失去了一些通用性并要求综合许多操作 尽管如此 管式反应器在液相反应中起着广泛作用 例 如 聚合反应 气 液反应几乎总是选择连续反应器 例如 高温裂解 采用管式反应器能够获得非常 高的产率 要么增加管的直径要么通过使用充足数量的并列管提高更大的通用性 6 Recycle reactors 6 循环反应器 Recycle reactor can be batch CSTR tubular and so on in nature with the purpose of the recycle varying from one case to the next Many large scale commercial processes 精品文档 10欢迎下载 incorporate the recycle of one or more streams back to an earlier point in the process to conserve raw materials This practice often results in the accumulation of impurities which in turn requires separation Usually it is not simply the reactor outlet stream that is recycled back to the reactor inlet but it can be For example in a batch reactor the reacting mixture can be recycled or pumped around through a heat exchanger to provide thermal control 循环反应器出于从一种情况到下一种情况循环变化的目的 在种类上可以是间歇反应器 连续流动 搅拌反应器 管式反应器等等 回到较早的观点 在节省粗原料的过程中 许多大规模的商业操作合并 了一个或多个循环 这一实践通常导致了杂质的累积 它们依次需要分离 通常不是简单地将反应器的 出料返回到入口 当然也可以这样做 例如 在间歇反应器中反应混合物可以回收 或用泵打循环 通 过热交换器控制热 Recycle reactor have also found valuable application in the laboratory and pilot plant because of their special characteristics At one extreme in which all of the product is recycled no net flow the reactor is the exact equivalent of the well stirred batch reactor At the other extreme of no recycle the reactor is simply the tubular variety If there is some net flow but the recycle rate is high the overall reactor performs like a CSTR Yet the reaction tube itself behaves like differential tubular reactor This versatility of the recycle reactor can be exploited to great advantage in research and development 循环反应器由于其特殊的特性在实验室和中试车间也发现了应用价值 一个极端是将所有的产物循 环 没有净的流出 此时循环反应器严格等效于全混间歇反应器 另一个极端是没有循环 反应器是 简单的管式类 假如有一些净的流出但循环率很高 所有的反应器运行类似于连续流动搅拌反应器 然 而反应器本身的 类似于不同的管式反应器 在研究和发展中循环反应器的通用性能够开发出更大的优 点 势 Bisio A Kabel R L Scaleup of Chemical Processes New York John Wiley computer modeling has also 精品文档 12欢迎下载 been described 今天这种生产过程仍是胶体聚合反应的基础 如图 14 1 所示一个重要的进步是连续操作 也采用 计算机模型描述 In the continuous process styrene butadiene soap initiator and activator an auxiliary initiating agent are pumped continuously form storage tanks through a series of a