The revised definition makes no sharp distinction between bulk and solution polymerizations and thus reflects industrial practice. Several so-called bulk processes for polystyrene and ABS? use 5%~15% solvent as a processing aid and chain-transfer agent. 在修正定义中本体和溶液聚合没有明确的界限，所以能应用于工业中。聚苯乙烯和ABS的本体过程使用5%~15%溶剂作为加工助剂和链转移剂。

Few successful processes have used the very large amounts of solvent needed to avoid high viscosities in the continuous phase, although this approach is sometimes used for laboratory preparations.

尽管有时实验室制备中使用了大量的溶剂避免连续相中的高粘度，但在成功的工艺中很少使用这种方法。

Bulk polymerizations often exhibit a second, discontinuous phase. They frequently exhibit high exothermicity, but this is more characteristic of the reaction mechanism than of bulk polymerization as such.

本体聚合往往出现第二个非连续相。他们常常表现出高放热性，但这一特点更多的是来自于反应机理，而不是本体聚合。

Bulk polymerizations of the free-radical variety are most common, although several commercially important condensation processes satisfy the revised definition of a bulk polymerization.

虽然有一些商业化的缩聚满足本体聚合的修订定义，但自由基聚合最常用于本体聚合。

In all bulk polymerizations, highly viscous polymer solutions and melts are handled. This fact tends to govern the process design and to a lesser extent，the process economics. 在所有的本体聚合中都处理高粘度的聚合物溶液和熔体。(本体聚合过程的高粘现象)支配聚合过程的设计和工艺的经济效益。

Suitably robust equipment has been developed for the various processing steps, including stirred-tank and tubular reactors, flash devolatilizers, extruder reactors, and extruder devolatilizers.

人们研制了耐用的设备用于不同的处理步骤，包括搅拌式和管式反应器中，闪蒸脱挥发，挤出机反应器和挤出机脱挥发器。

Equipment costs are high based on working volume, but the volumetric efficiency of bulk polymerizations is also high. If a polymer can be made in bulk, manufacturing economics will most likely favor this approach. ?

这些设备单位单位体积成本高，但本体聚合的体积效率也很高。如果某一聚合物可以通过本体聚合生产，经济学上该工艺是最适宜的。

It is tempting to suggest that polymer processes will gradually evolve toward bulk.? Recently, the suspension process for impact polystyrene has been supplanted by the bulk process, and the emulsion process for ABS may similarly be replaced. 有一种观点认为聚合物生产将逐渐向本体聚合发展。最近抗冲击的苯乙烯的本体聚合取代了悬浮聚合，ABS本体聚合代替了乳液聚合。

However, the modern gas-phase process for polyethylene appears to represent an opposite trend. It seems that polymerization technology tends to eliminate solvents and suspending fluids other than the monomers themselves.

然而，现代气相法聚乙烯似乎走相反的趋势。看来，相比于使用本体聚合，聚合技

术更多倾向于消除溶剂和悬浮液。

When the monomer is a solvent for the polymer, bulk processes as described in this article are chosen. When the monomer is not a solvent, suspension and slurry processes like those for polyethylene and polypropylene are employed. Hence, it is worthwhile avoiding a highly viscous continuous phase, but not at the price of introducing extraneous material. ?

当单体是聚合物的溶剂时，人们选择本文中所描述的本体聚合。当单体不是溶剂时，如聚乙烯和聚丙烯，人们使用悬浮和淤浆过程。这样，可避免高粘性的连续相，又不需引入外来物质。

UNIT 16 Styrene-Butadiene Copolymer

The synthetic rubber industry, based on the free-radical emulsion process, was created almost overnight during World War II. Styrene-butadiene (GR-S) rubber created at that time gives such good tire treads that natural rubber has never regained this market. 以自由基乳液过程为基础的合成橡胶工业在第二次世界大战期间几乎一夜而成。那时，丁苯橡胶制造的轮胎性能相当优越，使天然橡胶在市场黯然失色。

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 “short-stop”, such as hydroquinone (approximately 0.1 part), to quench radicals and prevent excessive branching and microgel formation.

混合物加热搅拌，50℃下转化率为每小时5%～6%。在转化率达70%～75%时，通过加入“终止剂”如对苯二酚（大约0.1的重量百分含量）来淬灭自由基并避免过量支化和微凝胶形成，使聚合反应终止。

Unreacted butadiene is removed by flash distillation, and syrene by steam-stripping in a column. After addition of an antioxidant, such as N-phenyl-β-naphthylamine (PBNA) (1.25 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. 未反应的丁二烯通过闪蒸去除，苯乙烯在塔中通过蒸汽去取。乳液在加入抗氧剂如N-甲基-β-萘胺（1.25的重量百分含量）后，加入盐水凝胶，然后加入稀硫酸或硫酸铝。凝胶碎片洗涤、干燥并包装装运。

This procedure is still the basis for emulsion polymerization today. An important improvement is continuous processing illustrated in Fig. 16.1; computer modeling has also been described.

今天这种生产过程仍是乳液聚合反应的基础。如图16.1所示一个重要的改进是连续操作；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 from storage tanks through a series of agitated reactors at such a rate that the desired degree of conversion is reached at the last reactor.

在连续操作中，苯乙烯、丁二烯、肥皂、引发剂和活化剂（一种助引发剂）用泵从储罐通过一系列的混合反应器，泵送流率根据末釜的转化率控制。

Shortstop is added, the latex warmed with steam, and the unreacted butadiene flashed off. Excess styrene is steam-stripped, and the latex finished as shown in Fig.

16.1.

加入终止剂，乳液用蒸气加热，用闪蒸去除未反应的丁二烯。剩余的苯乙烯用蒸气去除，如图16.1表示加工工艺。

SBR prepared from the original GR-S recipe is often called hot rubber; cold rubber is made at 5℃ by using a more active initiator system. Typical recipes are given in Table 16.1. At 5℃ ,60% conversion to polymer occurs in 12~15h. 由常规丁苯制法制备的丁苯胶常称作热胶；冷胶通过使用一种更高活性的引发体系在5℃制成。常用配方在表16.1中给出。在5℃下，聚合物12～15 h的转化率为60%。 Cold SBR tire treads are superior to those of hot SBR. Polymers with abnormally high molecular weight (and consequently too tough to process by ordinary factory equipment) can be processed after the addition of up to 50 parts of petroleum-base oils per hundred parts of rubber (phr).

冷丁苯橡胶轮胎性能优于热丁苯胶。对于非常高分子量的聚合物，由于采用常规的工厂设备由于太粘稠而难以加工，需要在每一百份的橡胶中加入最高50份的石油基的油后才能够加工。

These oil extenders make the rubbers more processible at lower cost and with little sacrifice in properties; they are usually emulsified and blended with the latex before coagulation.

这些油添加剂使橡胶更易加工、成本更低和而基本不降低性能；他们在凝胶之前通常乳化并与胶乳混合。

Recent trends have been toward products designed for specific uses. The color of SBR, which is important in many nontire uses, has been improved by the use of lighter-colored soaps, shortstops, antioxidants, and extending oils. 最新的趋势是设计特殊用途的产品。由于丁苯橡胶的颜色对许多非轮胎的使用十分重要，因此通过使用浅色的乳化剂、终止剂、抗氧剂和扩展油加以改进其颜色。

For example, dithiocarbamates are substituted for hydroquinone as shortstop; the latter is used on hot SBR where dark color is not objectionable. A shortstop such as sodium dimethyldithiocarbamate is more effective in terminating radicals and destroying peroxides at the lower temperatures employed for the cold rubbers.

例如，使用二硫代氨基甲酸盐替代对苯二酚作为终止剂；后者用于深颜色的热丁苯橡胶。在低温冷胶的制备中，二甲基二硫代氨基甲酸钠等终止剂对终止自由基和破坏过氧化物更有效。

Free-radical dissociative initiators that function by dissociation of a molecule or ion into two radical species are normally limited to inorganic persulfates in the case of butadiene polymerization.

在丁二烯聚合反应中，自由基分解类引发剂由分子或离子分解产生两个自由基，它们通常局限于过硫酸盐。

The other important class of free-radical initiators, redox systems, contain two or more components that react to produce free radicals. Dodecyl mercaptan added to control molecular weight also appears to aid free-radical formation by reaction with persulfate.

氧化还原体系是另一种重要的自由基引发剂，它含有通过反应产生自由基的两种或多种组分。用来控制分子量的十二烷基硫醇与过硫酸盐反应看上去也有助于自由基的

形成。

The commercial importance of such chain-transfer agents or modifiers cannot be overemphasized. Without molecular weight control the rubbers would be too tough to process.

这种链转移剂或调节剂具有极其重要的商业价值。不控制分子量橡胶将过于粘稠以致难以加工。

UNIT 23 Polymer Processing

Polymer processing , in its most general context , involves the transformation of a solid ( sometimes liquid ) polymeric resin , which is in a random form (e. g. powder, pellets , beads ), to a solid plastics product of specified shape , dimensions , and properties.

在其最一般的情况下，聚合物加工涉及固体（有时侯是液体）聚合物树脂的转变。树脂从一种不规则的形式（例如粉末、颗粒、珠子）转化成一种具有特定形状、尺寸和性能的固体塑料产品。

This is achieved by means of a transformation process: extrusion, molding, calendering , coating, thermoforming , etc. The process, in order to achieve the above objective, usually involves the following operations: solid transport , compression, heating, melting, mixing, shaping, cooling, solidification, and finishing .

这借助于转换加工：挤出、模塑、压延、涂敷、热成型等。为了获得上述目的，加工通常涉及下述操作：固体输送、压缩、加热、混合、成型、冷却、固化并完成。 Obviously, these operations do not necessarily occur in sequence, and many of them take place simultaneously.

显然，这些操作不必按序发生，他们中许多可以同时发生。

Shaping is required in order to impart to the material the desired geometry and dimensions. It involves combinations of viscoelastic deformations and heat transfer, which are generally associated with solidification of the product from the melt.

成型是为了给予材料所需要的几何形状和尺寸。成型过程涉及粘弹形变和热传递，这种粘弹形变和热传递是和产品从熔体的固化（或冷却）相联系的。

Shaping includes : (1) two-dimensional operations , e.g. dieforming, calendering and coating , and (2) three-dimensional molding and forming operations. 成型包括：（1）二维操作，例如，口模成型、压延和涂敷，（2）三维的模塑和成型操作。

Two-dimensional processes are either of the continuous , steady state type )e.g. film and sheet extrusion , wire coating , paper and sheet coating ,calendering ,fiber spinning , pipe and profile extrusion , etc. ) or intermittent as in the case of extrusions associated with intermittent extrusion blow moulding.

二维的操作要么是连续的固定形式。例如薄膜和板材挤出，电线涂布，纸和平面涂布，压延，纤维旋涂，管材和型材挤出等等。）要么是间歇式的，在挤出的情况下伴有间歇挤出吹塑。

Generally, moulding operations are intermittent, and, thus, they tend to involve unsteady state conditions. Thermoforming, vacuum forming, and similar processes may be considered as secondary shaping operations, since they usually involve the reshaping of an already shaped form. In some cases, like blow molding, the process involve primary

shaping (parison formation) and secondary shaping (parison inflation ).

通常，模塑操作是间歇的，然而同时倾向于非固定条件。因为热成型，真空成型和类似的加工通常包括已成型形状的再次成型，它们可以认为是二次成型操作。在某些情况下像吹模，加工包括首次成型（型胚成型）和二次成型（型胚膨胀）。

Shaping operations involve simultaneous or staggered fluid flow and heat transfer. In two-dimensional processes, solidification usually follows the shaping process, whereas solidification and shaping tend to take place simultaneously inside the mold in three dimensional processes.

成型操作包括同时或交叉的液体流动和热传递。在二维加工中，固化（或冷却）在成型加工以后，反之在三维加工的模塑中固化 （或冷却）和成型倾向于同时发生。 Flow regimes, depending on the nature of the material, the equipment, and the processing conditions, usually involve combinations of shear, extensional, and squeezing flows in conjunction with enclosed (contained) or free surface flows.

根据材料的性质、设备和加工条件，流动形式通常包含 剪切、拉伸。根据流动面为包含表面或自由表面 ，又包含挤压流动。

The thermo-mechanical history experienced by the polymer during flow and solidification results in the development of microstructure (morphology, crystallinity, and orientation distributions) in the manufactured article.

聚合物热机械工艺经历流动和固化（或冷却）过程，其导致了制造产品微结构（形态学、结晶学和取向分布）的发展。

The ultimate properties of the article are closely related to the microstructure. Therefore, the control of the process and product quality must be based on an understanding of the interactions between resin properties, equipment design, operating conditions, thermo-mechanical history, microstructure, and ultimate product properties. 最终产品的性能与微结构紧密相关。因此，加工和产品质量的控制必须基于树脂性能、设备设计、操作条件、热机械过程、微结构和最终产品性能之间相互作用的理解。 Mathematical modeling and computer simulation have been employed to obtain an understanding of these interactions.

数学模型和计算机模拟被同时用于获得这些相互作用的理解。

Such an approach has gained more importance in view of the expanding utilization of computer aided design/computer assisted manufacturing/computer aided engineering (CAD/CAM/CAE) systems in conjunction with plastics processing.

广泛利用计算机辅助设计/计算机辅助制造/计算机辅助工程（CD/CAM/CAE）系统用于塑料加工，使得诸如这种方法重要性大为提高。

The following discussion will highlight some of the basic concepts involved in plastics shaping operations. It will emphasize recent developments relating to the analysis and simulation of some important commercial processes, with due consideration to elucidation of both thermo-mechanical history and microstructure development. 下面的讨论将重点放在包括塑料成型操作一些基本概念上。将着重介绍最近一些重要商品加工的分析和模拟的进展，并阐明热机械过程和微结构发展。

More extensive reviews of the subject can be found in standard references on the topic (1~6).

在参考文献（1～6）中能够找到本主题更广泛的综述。