端基四肽聚异戊二烯的合成表征及流变性能

文中对四肽封端的聚异戊二烯的合成方法和流变性能进行了初步探索。首先采用新癸酸钕/二异丁基氢化铝/二氯二甲基硅稀土催化剂体系催化异戊二烯聚合,得到了相对分子质量可控,窄分布(1.09~1.4),顺1,4结构含量高(96%)的聚异戊二烯。聚合4 h后用二氧化碳封端得到端羧基聚异戊二烯(PI-COOH)。非水滴定结果表明羧基封端率高(100%)。然后PI-COOH与四肽(Boc-(ala)_4-NH_2)缩合形成端基为四肽的聚异戊二烯(PI-4A)。流变测试结果表明,与PI-COOH相比,PI-4A中四肽的分子间氢键作用使得储能模量提高了约1000倍;并且在升温过程中氢键被逐渐破坏,模量快速下降,在50℃时大部分氢键断裂。     

二甲基甲酰胺法碳五馏分分离萃取精馏塔的模拟

利用Aspen Plus流程模拟软件,对二甲基甲酰胺(DMF)法萃取精馏分离裂解碳五馏分(C5)的第一萃取精馏塔进行模拟,考察溶剂和C5的进料位置、溶剂比(DMF进料流量与C5进料流量的比)、回流比、溶剂进料温度等因素对分离效果的影响。与实际生产装置工艺参数的对比结果表明,模拟计算的结果准确、可靠。模拟结果表明,当溶剂进料位置为第4~5块塔板、C5进料为第26块塔板、溶剂比为6~7、回流比为3、溶剂进料温度为60~70℃时,第一萃取精馏塔的分离效果最佳。     

Hydrogenated linear block copolymers of butadiene and isoprene: effects of variation of composition and sequence architecture on properties

The effect of variations in molecular architecture and composition on bulk properties is reported for a series of well characterized hydrogenated block copolymers of butadiene (HB) and isoprene (HI), each with a total molecular weight of ～ 200 000 and a narrow distribution ($\text{Mw}\text{Mn}\text{<1.17}$). The polymers were synthesized by sequential anionic polymerization followed by hydrogenation, using p-toluenesulphonylhydrazide. The material properties of the homopolymeric HI and HB were also investigated. As expected, HI is rubbery at room temperature and HB is a tough semicrystalline plastic with properties similar to those of a low density polyethylene, LDPE. The crystallinity, density and ΔH_t for all of the block copolymers were found to be linearly dependent on HB content indicating that little mixing exists between the HB and HI blocks in the solid state. Although the solution cast films of the block copolymers were spherulitic, the quenched films displayed no distinct structure on the supermolecular level indicating that the aggregation of the crystallites was more random in these films. The stress-strain properties of triblock copolymers with different block sequence, HBIB and HIBI, and a di-block copolymer, HBI, were similar in bulk behaviour to each other in the high and the intermediate butadience content (50–90%). This was related to the fact that the mechanical properties were determined predominantly by the behaviour of the more continuous HB phase. For the lower butadiene compositions (7–29%), there was a major difference in the behaviour of polymers with different block architecture. HBIB polymers were thermoplastic elastomers, whereas HIBI polymers behaved like an uncured particulate filled rubber. This difference was related to the presence of permanent ‘entanglements’ in HBIB polymers. The permanent entanglements which act as a physical crosslink are a consequence of the anchorage of the HB end blocks in the semicrystalline domains. No such arrangement is possible for either the HIBI or HBI polymers. The hysteresis behaviour of HBIB polymers were strongly dependent on butadiene content, decreasing with lowering of the concentration of the semicrystalline HB. This dependence was related to the continuity of the crystalline microdomains. All the members of HIBI series (and the HBI we considered) showed large hysteresis behaviour. This large energy loss during cyclic deforn ation in these polymers was related to the absence of the permanent anchor points arising from end block crystallization.     

裂解C_5中异戊二烯阻聚工艺条件研究

在玻璃封管里比较了乙醇胺(C2H7NO)、硝基苯(C6H5NO2)、N-甲基吡咯烷酮(NMP)、邻硝基苯酚(ONP)、亚硝酸钠(NaNO2)对异戊二烯(IP)自由基聚合的阻聚效果,阻聚活性的次序为ONP>NaNO2>NMP>C6H5NO2>C2H7NO。并重点考察了反应温度、反应时间、加入量对ONP阻聚作用的影响。结果表明:温度越高,IP聚合速度越快。IP损失率与反应时间呈线性关系。阻聚效果较好的ONP的质量分数范围为0.3%—1.5%。     

Classification of polar additives with respect to their influence on the microstructure in anionic polymerization of isoprene with butyllithium by transition energy measurements

A transition energy scale was established on the basis of dimethyl indoaniline as organic dye for 23 mono- and bidentate polar additives. From polymerization experiments of isoprene with s-butyllithium in mixtures of n-hexane and the selected bases, the microstructure of polyisoprenes was determined by ¹H-NMR spectroscopy. The vinyl contents of these polymers could be satisfactorily correlated with the transition energy measurements. However, it turned out that especially bidentate bases do not fit into this scheme. Obviously, besides their influence on the polarity of the reaction solution, they exhibit special interactions with the growing centers. The developed correlations allow the prediction of 1,2- and 3,4-linkages in polyisoprenes from anionic polymerization of isoprene with butyllithium in polar solvents in the presence of low concentrations, also of bases hitherto not investigated. The temperature dependence of the microstructure can likewise be estimated. As in the case of butadiene, at least for weak bases, it was found that the vinyl contents depend primarily on the polarity of the reaction mixture determined by the base concentration and not on the molar ratio of base to initiator. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1533–1547, 1999     

苯磺酰氯和异戊二烯加成反应研究

以氯化铜为催化剂,三乙胺盐酸盐为相转移催化剂,在加压条件下苯磺酰氯和异戊二烯加成合成了辅酶Q10的重要中间体--反式1-苯磺酰基-2-甲基-4-氯-2-丁烯,其结构经红外光谱和1H NMR得以证实.提出的反应机理较好地解释了实验结果和现象.研究表明,合适的反应条件为: 反应温度90～100℃,异戊二烯和苯磺酰氯的摩尔比为1∶1.2,产物收率为75%;催化剂氯化铜不仅提高了反应速度,而且抑制了聚合副产物的生成;添加三乙胺盐酸盐改善了铜盐在有机溶剂中的溶解性,从而改善了催化效果.     

When emulsification meets self-assembly: The role of emulsification in directing block copolymer assembly

Emulsification is used to generate spherical particles or droplets of immiscible liquids, while block copolymer self-assembly yields a wide variety of nanostructures. The combination of these two methodologies can yield a variety of structures that would not be otherwise observed. The emulsification/solvent evaporation process provides a powerful means to direct block copolymer assembly. Various factors arising from the emulsification can direct the block copolymer assembly, such as confinement effects, interfacial tension, as well as other conditions. In this review, various emulsification techniques are discussed, such as oil-in-water emulsions, double emulsions, as well as the use of microfluidic devices. While emulsification-induced self-assembly may be used to control internal morphologies as well as overall shapes of particles, it also lends a convenient method for controlling surface structures. Examples of exotic structures that may be obtained through the use of these techniques will be described. Also, ways in which morphologies may be controlled using these methods will be discussed.     

苯乙烯/异戊二烯/丁二烯(S/I/B)星型嵌段聚合物的研制方法

介绍了近年来的苯乙烯／异戊二烯／丁二烯（S／I／B）星型嵌段聚合物的发展与研制方法。重点评述了星型嵌段聚合物SIB、IB、IBI、SIS的研制方法，提出应用阴离子聚合方法合成星型聚合物的巨大潜力以及目前的任务。     

异戊橡胶在全钢载重子午线轮胎带束层胶中的应用

研究异戊橡胶（IR）在全钢载重子午线轮胎带束层胶中的应用。结果表明。采用20～30份IR等量替代天然橡胶（NR）,混炼胶的门尼粘度较低,硫化胶的邵尔A型硬度、定伸应力和撕裂强度减小,拉断伸长率稍大,粘合性能稍好,生热降低,其他性能变化不大。采用20份IR等量替代NR用于生产,成品轮胎的耐久性能符合国家标准要求。     

微观结构组成对乳聚集成橡胶性能的影响

探讨微观结构组成对乳聚集成橡胶(ESIBR)性能的影响。结果表明:随着分子结构中丁二烯含量增大,混炼胶的焦烧时间和正硫化时间延长,硫化胶的拉伸强度、拉断伸长率、撕裂强度和回弹值逐渐增大;分子结构组成中苯乙烯、异戊异烯和丁二烯质量比为1∶1.3∶1.6的ESIBR物理性能和动态性能达到良好平衡。