【作者】 谷巨明；

【导师】 付志峰；

【作者基本信息】 北京化工大学 ， 高分子化学与物理， 2010， 博士

【摘要】 鉴于氯丁二烯的活性自由基聚合及其嵌段共聚物的合成尚未有文献报导,本论文主要研究了碘仿作为链转移剂应用于氯丁二烯乳液聚合体系所表现出的可控自由基聚合特征；进而尝试采用碘原子退化转移自由基溶液和种子乳液聚合法制备了含聚氯丁二烯和聚苯乙烯组份的两嵌段共聚物,还考察了溶液聚合条件下,不同大分子碘代化合物作为链转移剂合成双组份嵌段共聚物的活性差异；初步探讨了碘仿取代调丁作为分子量调节剂合成的三种新型氯丁橡胶之综合性能并与传统调丁调节型CR-244、CR-232及混合调节型CR-322(含调丁和硫磺)氯丁橡胶性能进行了比较。具体工作如下：1.用碘仿作为链转移剂取代调丁,依照国内传统粘接型CR-244氯丁橡胶大生产配方及反应条件,顺利地进行了氯丁二烯的实验室低温乳液聚合,通过单体转化率、凝胶色谱(GPC)测试所得的相对数均分子量、分子量分布系数、分子量分布曲线及1H NMR核磁谱图等参数的分析,验证了一定量碘仿参与下的氯丁二烯自由基乳液聚合体系具有与苯乙烯溶液体系相似的活性自由基聚合特征并生成了链末端带有碘原子的聚氯丁二烯(PCP-I)结构。2.用碘仿作为退化链转移剂,采取以上方法先制得碘原子封端结构的聚氯丁二烯(PCP-I).然后,用PCP-I作为大分子链转移剂,在AIBN引发下,进行苯乙烯的溶液聚合。该反应呈现出了一定的可控聚合的特点,得到了PCP-b-PS两嵌段聚合物,通过GPC和1H NMR核磁谱图等测试手段验证了共聚物的嵌段结构,但是苯乙烯转化率最高只能达到30%。反之,先进行碘仿存在下的苯乙烯可控聚合,用所得链末端带有碘原子的聚苯乙烯(PS-I)作为大分子链转移剂,在AIBN引发下,进行氯丁二烯的溶液聚合,则无法合成明显的PCP-b-PS两嵌段聚合物。这说明PS-I大分子链转移剂对氯丁二烯的转移引发活性较低,而PCP-I大分子链转移剂对苯乙烯的转移引发活性较高。3.用含碘化合物作为链转移剂,通过种子乳液聚合的方法合成PCP-b-PS两嵌段聚合物。首先,用碘仿作为退化链转移剂,按照传统粘接型CR-244氯丁橡胶大生产配方及反应条件,进行了氯丁二烯的低温乳液聚合,得到一定分子量的聚氯丁二烯(PCP-I)种子乳液。然后,将乳液体系中剩余的未反应氯丁二烯单体真空脱气排出,再加入第二单体苯乙烯进行以PCP-I作为大分子链转移剂的苯乙烯种子乳液聚合。通过单体转化率、GPC测试数据、1H NMR核磁谱图等测试分析,验证了该反应具有一定的可控聚合的特征,且反应活性明显好于前述溶液聚合法嵌段苯乙烯的结果,成功地得到了相对分子量分布变窄且苯乙烯转化率非常高的PCP-b-PS两嵌段聚合物。4.用碘仿取代调丁作为分子量调节剂,按照国内传统粘接型CR-244和通用型CR-232及CR-322(混合调节型)三种氯丁橡胶大生产配方及反应条件,通过氯丁二烯的乳液聚合,合成了碘仿调节型CR-244、CR-232和碘仿／硫磺混合调节型CR-322三个新品种的氯丁橡胶,并与传统调丁调节型CR-244、CR-232和调丁／硫磺混合调节型CR-322氯丁橡胶综合性能进行了比较。更多还原

【Abstract】 To the best of our knowledge, the study on living free radical polymerization of chloroprene and the synthesis of its block copolymers has never been reported. In this dissertation, the controlled radical polymerization characteristics of chloroprene emulsion polymerization was mainly researched with iodoform as chain transfer agent; the methods of degenerative transfer radical solution and emulsion polymerization (DTRP) was further studied to attempt at preparing polychloroprene and polychloroprene-b-polystyrene block copolymers (PCP-b-PS), also the reaction activity difference of using various iodide polymers as macro-chain transfer agents was investigated to synthesize diblock copolymers via solution polymeriation; the comprehensive properties of three new kinds of chloroprene rubbers (CR) prepared with iodoform as molecular weight regulator instead of traditional regulator D (isopropyl xanthogen disulfide) was preliminarily discussed and meanwhile made comparison with those of the traditional regulator D mediated CR-244, CR-232 as well as compound regulator mediated CR-322 (regulator D plus sulfur). The detailed work is as follows:1. Employing iodoform as chain transfer agent to replace the traditional regulator D, the chloroprene low-temperature emulsion polymerization was smoothly carried out in lab based on the domestic traditional industrial large-scale production formula and reaction conditions of adhesive type CR-244. Through analyses of monomer conversions, Gel Permeation Chromatography (GPC) determined relative number-average molecular weights, molecular weight distributions, as well as Nuclear Magnetic Resonance (’HNMR) spectra, etc., the chloroprene emulsion polymerization was found to have the characteristics of living free radical polymerization, similar to those of styrene solution polymerization system, giving the structure of iodine atom-ended polychloroprene (PCP-I).2. Adopting iodoform as chain-transfer agent, the iodine atom-ended polychloroprene was prepared first in accordance with the aforementioned method. Then styrene solution polymerization was conducted in toluene with AIBN as initiator and the above obtained polychloroprenes as macro-chain transfer agents. The polymerization process showed living free radical features, however styrene conversion could only reach up to 30%. PCP-b-PS diblock copolymers were acquired successfully and further confirmed by GPC and’HNMR Spectroscopy. In addition, the preparation of PCP-b-PS diblock copolymers was attempted as well using reverse route. Firstly, styrene radical solution polymerization was proceeded based on AIBN as initiator and iodoform as chain-transfer agent, giving iodine atom-ended polystyrene (PS-I) with controlled molecular weights. Secondly, chloroperene was polymerized in toluene with the synthesized PS-I as macro-chain transfer agents, to attempt for the preparation of PCP-b-PS diblock copolymers. However due to lower initiation efficiency of PS-I to chloroprene monomer comparing with that of PCP-I to styrene monomer, the PCP-b-PS diblock copolymer attempt was not as successful as when PCP-I macro-chain transfer agents were used.3. Taking iodide as chain-transfer agent, PCP-b-PS diblock copolymers were prepared through seed emulsion polymerization. In the first place, based on the domestic traditional industrial large-scale production formula and reaction conditions of adhesive type CR-244, the chloroprene free radical emulsion polymerization was performed by iodoform as the degenerative chain transfer agent to obtain the iodine atom-ended polychloroprene seed latex. After the unpolymerized chloroprene was devolatilized under vacuum, styrene was then added and the emulsion polymerization of styrene using above obtained polychloroprenes as macro-chain transfer agents was proceeded. The seed emulsion polymerization indicates more obvious living free radical characteristics and better reaction activity than the result of before-mentioned solution polymerization method in terms of the blocking reaction with styrene. Therefore, more narrowly distributed PCP-b-PS diblock copolymers at much higher styrene conversion were successfully prepared and further confirmed by GPC and 1HNMR Spectroscopy.4. Applying iodoform as molecular weight regulator to substitute traditional regulator D, three new kinds of CR were synthesized through chloroprene emulsion polymerization according to the domestic traditional industrial large-scale production formulas and reaction conditions of adhesive type CR-244 and general purpose types of CR-232, CR-322 (compound regulation type), and the relative contrasts were made with regard to CR comprehensive properties between iodofrm and regulator D respectively mediated CR-244, CR-232 as well as CR-322 (iodofrom or regulator D plus sulfur).更多还原