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improvement is continuous processing illustrated in Fig. 14.1; computer modeling has also 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 agitated reactors at such a rate that the desired degree of conversion is reached at the last reactor. 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. 14.1.
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。加入终止剂,乳液用蒸气加热,未反应的丁二烯被闪蒸。剩余的苯乙烯被蒸气剥离,如图14.1表示乳液完成。
表14.1 冷丁苯胶的典型配方 组分
丁二烯 苯乙烯
特十二烷基硫醇 过氧化二异丙苯 过氧化薄荷烷 硫酸亚铁七水合物 焦磷酸钾
磷酸钠十水合物 乙二胺四乙酸钠 甲醛次硫酸钠
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配方1 72 28 0.2 0.08 0.14 0.18
配方2 71 29 0.18 0.08 0.03 0.5 0.035 0.08
高分子专业英语选讲课文翻译资料
松香酸 水 4.0 180 4.5 200
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 14.1 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。典型的配方在表14.1中给出。5℃、60%转化率、12~15 h聚合物形成。
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). 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.
冷丁苯橡胶轮胎优于那些热丁苯胶。具有异常高的分子量的聚合物(因此采用常规的工厂设备由于太粘稠而难以加工)在每一百份的橡胶中加入大于50份的石油基础油后能够加工。这些油添加剂使橡胶更易加工体现在低成本和性能方面低损耗;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. 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.
最近倾向于设计特殊用途的产品。丁苯橡胶的颜色,在许多非轮胎使用中十分重要,通过使用浅色的肥皂、终止剂、抗氧剂和扩展油加以改进。例如,二硫化氨基甲酸盐替代对苯二酚作为终止剂;后者适用于不被人反对的黑色丁苯橡胶。在冷胶的制备中如二硫化氨基甲酸钠的终止剂在低温情况下对终止自由基和消灭过氧化物更有效。
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.
在丁二烯聚合反应过程中自由基分解的引发剂即一分子分解或离子成两个自由基物种的引发剂通常限制于过硫酸盐。
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. The commercial importance of such chain-transfer agents or
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高分子专业英语选讲课文翻译资料
modifiers cannot be overemphasized. Without molecular weight control the rubbers would be too tough to process.
其他重要的自由基引发剂类别,氧化还原体系,包含反应产生自由基的两种或多种组分。加入控制分子量的十二烷基硫醇与过硫酸盐反应也出现了助自由基的形成。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难以加工。
--------Tate D p , Bechea T W. Encyclopedia of Polymer Science and Engineering, 2nd ed.
Vol. 2. Editor-in-chilf Kroschwitz JI. New York: John wiley & Sons, 1985. 553~555
C 聚合物材料的加工、性能和应用 UNIT 21 Polymer Processing 第二十一单元 聚合物加工
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. 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 . Obviously, these operations do not necessarily occur in sequence, and many of them take place simultaneously.
在其最一般的情况下,聚合物加工涉及固体(有时侯是液体)聚合物树脂以一种不规则的形式(例如粉末、颗粒、珠子)转化成一种具有特殊形状、尺寸和性能的固体塑料产品。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。显然,这些操作不必按序发生,而许多可以同时发生。
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。它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. 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
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blow moulding. 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 ). 成型包括:(1)二元操作,例如,口模成型、压延和涂敷,(2)三元的模型和成型操作。二元的操作要么是连续的,固定形状(例如薄膜和板材,电线涂布,纸和平面涂布,压延,纤维拉伸,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膜。通常,模塑操作是间歇的,然而同时倾向于非固定条件。热成型,真空成型,和相似的加工可以认为是二次成型操作,因为它们通常包括已成型形状的再次成型。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. 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.
成型操作包括同时或交叉的液体流动和热传递。在二元加工中,固化(或冷却)伴随着成型加工,反之在三元加工的模塑中固化 (或冷却)和成型倾向于同时发生。根据材料的性质、设备和加工条件,流动状态以及根据流动面的自由与否,通常包括剪切、延伸和挤压流动。
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. 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. Mathematical modeling and computer simulation have been employed to obtain an understanding of these interactions. 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.
经历了流动和固化(或冷却)的聚合物热机械过程导致了制造业微结构的变革(形态学、结晶学和取向分布)。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。数学模型和计算机被同时用于获得这些相互作用的理解。鉴于进一步利用计
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算机辅助设计/计算机辅助制造/计算机辅助工程(CD/CAM/CAE)系统协同塑料加工诸如这一趋近获得了更多的重要性。
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. More extensive reviews of the subject can be found in standard references on the topic (1~6).
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。适当考虑说明热机械过程和微结构发展,将强调最近关于分析和一些重要商品加工模型的进展。在上端(1~6)的标准参考中能够找到本主题更广泛的综述。 As mentioned above, shaping operations involve combinations of fluid flow and heat transfer, with phase change, of a visco-elastic polymer melt. Both steady and unsteady state processes are encountered. A scientific analysis of operations of this type requires solving the relevant equations of continuity, motion, and energy (i.e. conservation equations).
如上面提到的,成型操作包括液体流动和热传递,对于相态变化,还包括粘弹性聚合物的熔融。稳定和非稳定状态加工是相冲突的。这种典型操作的科学分析需要解决相关连续、运转和能量平衡(如守恒方程)。
——Austarita G , Nicolas L. Polymer prscessing and properties
New York: Plenum press 1984, 1~3
UNIT 29 Synthetic Plastics UNIT 23 聚合物加工
在其最一般的情况下,聚合物加工涉及固态(有时是液态)聚合物树脂以一种不规则的形式(如:粉状、球状、珠粒状)转化成一种具有特殊形状、尺寸和性能的固态塑料制品。这通过转变过程来实现:挤出、模塑、压延、涂覆、热成型等。为了实现上面的目的,加工过程通常涉及下述操作:固体输送、压缩、加热、熔融、混合、成型、冷却、固化及修饰。显然,这些操作不必按序发生,而许多可以同时发生。
通过成型可以赋予材料所需要的几何形状和尺寸。它包括黏弹性形变和热成型,这种黏弹性形变和热传递是和产品从熔体的固化相联系的。 成型包括:(1)二维操作,如:口模成型、压延及涂覆。(2)三维的模塑和成型操作。二维的操作要么是连续的固定队的形状(如:薄膜及片材挤出、电线的涂层、纸和片材涂覆、压延、纤维纺丝、管材和型材挤出等),要么是间歇式的,在挤出的情况下伴有间歇挤出吹膜。通常模塑成型操作是间歇式的,然而它们倾向于非固定条件。热成型、真空成型及类似过程可以被看做是二次成型操作,因为它们通常包括已成型形状的再次成型。在某些情况下,像吹塑,加工包括首次成型(型坯形成)和二次成型(型坯膨胀)。
成型操作包括同时或交错的液体流动和热传递。在二维加工中,固化伴随着成型加工,反之在三维加工的固化和成型往往在模具中同时发生。根据材料的性质、设备和加工条件的
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