Unit 16 Styrene-Butadiene Copolymer
农村建房合同第十四单元 丁二烯-苯乙烯共聚物
The synthetic rubber industry, bad on the free-radical emulsion process, was created almost overnight during World War II. Styrene-butadiene (GR-S) rubber crated at that time gives such good tire treads that natural rubber has never regained this market.
合成橡胶工业，以自由基乳液过程为基础，在第二次世界大战期间几乎很快地形成。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。
The GR-S standard recipe is
丁苯橡胶的标准制法是
愿望实现组分 | 重量分数 | 组分 | 重量分数 |
丁二烯 | 72 | 过硫酸钾 | 0.3 |
苯乙烯 | 25 | 肥皂片 | 5.0怦然心动的英语 |
十二烷基硫醇 | 0.5 | 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 “short-stop”, such as hydroquinone (approximately 0.1 part), to quench radicals and prevent excessive branching and microgel formation. 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.
混合物在搅拌下50℃加热，每小时转化5%～6%，在转化率达70%～75%时通过加入“终止剂” 聚合反应终止，例如对苯二酚（大约0.1的重量百分含量），抑制自由基并避免过量支化和微凝胶形成。未反应的丁二烯通过闪蒸去除，苯乙烯在萃取塔中通过蒸汽萃取（剥离）。在加入抗氧剂后，例如N-甲基-β-萘胺（1.25的重量百分含量），加入盐水，其次加入稀释的硫酸或硫酸铝后乳液凝胶。凝胶碎片被洗涤、干燥并包装装运。
Fig.14.1 SBR plant flow diagram Courtesy of Hydrocarbon Processing and Petroleum Refiner.
图14.1 丁苯橡胶厂流程图取自烃类加工和石油产品精制
This procedure is still the basis for emulsion polymerization today. An important 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。
创文工作总结In the continuous process, styrene, butadiene, soap, initiator, and activator (an auxiliary initiating agent) are pumped continuously form storage tanks through a ries 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 | 配方1 | 配方上唇有痣2 |
丁二烯 | 72 | 71 |
苯乙烯 | 28 | 29 |
特十二烷基硫醇 | 0.2 | 0.18 | 圆柱体侧面积公式
过氧化二异丙苯 | 0.08 | |
天文望远镜原理过氧化薄荷烷 | | 0.08 |
硫酸亚铁七水合物 | 0.14 | 0.03 |
焦磷酸钾 | 0.18 | |
磷酸钠十水合物 | | 0.5 |
乙二胺四乙酸钠 | | 国庆诗词0.035 |
甲醛次硫酸钠 | | 0.08 |
松香酸 | 4.0 | 4.5 |
水 | 180 | 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 tho of hot SBR. Polymers with abnormally high molecular weight (and conquently too tough to process by ordinary factory equipment) can be procesd after the addition of up to 50 parts of petroleum-ba oils per hundred parts of rubber (phr). The 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 us. The color of SBR, which is important in many nontire us, has been improved by the u of lighter-colored soaps, shortstops, antioxidants, and extending oils. For example, dithiocarbamates are substituted for hydroquinone as shortstop; the latter is ud 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 ca 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 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
