二乙二醇单乙醚基钡/三异丁基铝/正丁基锂引发体系合成高反式苯乙烯-异戊二烯-丁二二烯三元共聚物

以二乙二醇单乙醚基钡(简称Ba)/三异丁基铝(简称Al)/正丁基锂(简称Li)为三元引发体系,采用负离子聚合法合成了高反式苯乙烯-异戊二烯(Ip)-丁二烯(Bd)三元共聚物(SIBR),考察了引发剂组分、单体配比和聚合温度对SIBR微观结构的影响,并研究了Al/Li(摩尔比)和Bd/Ip(质量比)对SIBR结晶行为的影...     

以双四氢糠丙烷为极性调节剂的苯乙烯/异戊二烯/丁二烯三元共聚动力学

以正丁基锂(n-BuLi)为引发剂,双四氢糠丙烷(DTHFP)为极性调节剂,环己烷为溶剂,采用负离子聚合法合成了线型苯乙烯(St)-异戊二烯(Ip)-丁二烯(Bd)三元共聚物,考察了三元共聚合总反应速率的影响因素,研究了三元共聚合反应动力学,并与传统极性调节剂四氢呋喃(THF)体系进行了比较。结果表明,在单体质量分数为12%,St/Ip/Bd(质量比)为20/40/40,设计单臂相对分子质量为10×104的条件下,随着聚合反应温度的升高或DTHFP/n-BuLi(摩尔比)的增加,总转化率和总反应速率逐渐增大,聚合反应的假一级表观增长反应速率常数增大;表观增长反应活化能和频率因子均随DTHFP/n-BuLi值的增加而减小;DTHFP在用量较小的情况下与较大THF用量的效果相当,促进聚合反应速率的能力明显高于THF。     

用不对称醚作调节剂合成苯乙烯-异戊二烯-丁二烯橡胶的反应动力学

以苯乙烯(St)、异戊二烯(Ip)和丁二烯(Bd)为单体,正丁基锂(n-BuLi)为引发荆,乙基乙二醇叔丁基醚(BET)为结构调节剂,合成了线型无规结构的苯乙烯-异戊二烯-丁二烯橡胶(SIBR),进行了聚合反应动力学研究,并与以四氢呋喃(THF)为结构调节剂的体系进行了比较.结果表明,BET的加入提高了聚合反应速率;随反应温度的升高和BET/n-BuLi(摩尔比)的增大,聚合反应速率加快,尤其是St的反应速率提高显著;BET调节聚合速率的能力明显高于THF.     

星形SIBR共聚物结构与性能的关系研究

北京化工研究院燕山分院以环己烷为溶剂,苯乙烯(St)、丁二烯(Bd)以及异戊二烯(Ip)为单体,正丁基锂为引发剂,采用负离子聚合法合成了集成橡胶——星形苯乙烯-异戊二烯-丁二烯嵌段共聚物(SIBR),考察了星形SIBR的相对分子质量、侧基含量、嵌段比(即Ip的均聚物链段与     

多锂引发剂引发苯乙烯-丁二烯-异戊二烯的共聚反应动力学

用正丁基锂、二乙烯基苯和异戊二烯合成了可溶于非极性溶剂的多锂引发剂体系,用其制备了苯乙烯一丁二烯一异戊二烯三元共聚橡胶,研究了温度、N,N,N′、N′-四甲基乙二胺(TMEDA)／Li^ (摩尔比,下同)及引发剂浓度对其反应动力学的影响。结果表明,随着温度的升高、TMEDA用量的增加(此时TMEDA／Li^ 不大于1)、引发剂浓度的增加,各种单体的反应速率增加;在同一条件下,单体的表观增长反应速率常数由大到小依次为丁二烯、苯乙烯、异戊二烯。     

锡偶联型充油苯乙烯-异戊二烯-丁二烯三元共聚物的合成

以正丁基锂为引发剂、环己烷为溶剂、自制的二元复配调节体系为调节剂、四氯化锡为偶联剂,采用负离子聚合法合成了锡偶联型苯乙烯(St)-异戊二烯(Ip)-丁二烯(Bd)三元共聚物(SIBR),并用湿法充油技术制备了充油SIBR,研究了调节剂对SIBR三元共聚动力学的影响,考察了单体配比和微嵌段含量对SIBR及充油SIBR性能的影响,并对比了充油SIBR与3种通用胶(溶聚丁苯橡胶2305、乳聚丁苯橡胶1502和1712)的性能。结果表明,在SIBR三元聚合过程中,不添加调节剂时,Bd、Ip、St的聚合速率依次减慢,且St的聚合速率远小于前两者;在添加复配调节剂后,St的聚合速率大幅度提高,并超过Ip的聚合速率;当St/Ip/Bd(质量比)为20/40/40时,SIBR的300%定伸应力和拉伸强度呈现最大值;当St微嵌段质量分数小于1.0%时,充油SIBR具有良好的物理机械性能及优异的动态力学性能;充油SIBR的物理机械性能基本与3种通用胶相当,抗湿滑性优于3种通用胶,且滚动阻力小于3种通用胶。     

星形苯乙烯-异戊二烯-丁二烯嵌段共聚物结构与性能的关系

以环己烷为溶剂,苯乙烯(St)、丁二烯(Bd)、异戊二烯(Ip)为单体,正丁基锂为引发剂,采用负离子聚合法合成了集成橡胶———星形苯乙烯-异戊二烯-丁二烯嵌段共聚物(SIBR),考察了星形SIBR的相对分子质量、侧基含量、嵌段比(即Ip的均聚物链段与St-Bd的无规共聚物链段的质量比)与其性能的关系。结果表明,在考察范围内,星形SIBR的拉伸强度和撕裂强度随着其相对分子质量的增加而增大。随着1,2-和3,4-结构含量之和的增加,0℃和60℃时的损耗因子均有所增大。固定St/Bd(质量比)为1/3,随着嵌段比的逐渐降低,所得星形SIBR的门尼黏度逐渐增大;嵌段比为20/80时所得星形SIBR具有较好的力学性能与动态力学性能,且与溶聚丁苯橡胶2300、2305以及天然橡胶相比,具有更好的抗湿滑性和滚动阻力的平衡。     

氮官能化多锂引发合成星形苯乙烯-异戊二烯-丁二烯共聚物的微观结构和玻璃化转变温度

以六亚甲基亚胺锂(LHMI)与二乙烯基苯(DVB)合成的氮官能化多锂(简称Li)为引发剂,N,N,N′,N′-四甲基乙二胺(TMEDA)为极性调节剂,环己烷为溶剂,制备了带有氮官能化基团的星形无规苯乙烯-异戊二烯-丁二烯共聚物(SIBR),用核磁共振法进行了表征,并分析了TMEDA用量、聚合温度、引发剂浓度及DVB/Li(摩尔比)对SIBR微观结构和玻璃化转变温度(Tg)的影响。结果表明,在DVB/LHMI(摩尔比)为0.8的条件下,SIBR中有C—N存在,并且为臂数不等的星形聚合物;随着TMEDA用量的增加和聚合温度的降低,SIBR中非1,4-结构含量增加,Tg提高;在实验范围内引发剂浓度和DVB/Li对SIBR中非1,4-结构含量和其Tg影响不大。     

氮官能化多锂引发合成星形苯乙烯-戊二烯-二烯共聚物的微观结构和玻璃化转变温度

以六亚甲基亚胺锂（LHMI）与二乙烯基苯（DVB）合成的氮官能化多锂（简称Li）为引发剂，N，N，N’，N’-四甲基乙二胺（TMEDA）为极性调节剂，环己烷为溶剂，制备了带有氮官能化基团的星形无规苯乙烯-异戊二烯-丁二烯共聚物（SIBR），用核磁共振法进行了表征，并分析了TMEDA用量、聚合温度、引发剂浓度及DVB/Li（摩尔比）对SIBR微观结构和玻璃化转变温度（Tg）的影响。结果表明，在DVB/LHMI（摩尔比）为0．8的条件下，SIBR中有C-N存在，并且为臂数不等的星形聚合物；随着TMEDA用量的增加和聚合温度的降低，SIBR中非l，4-结构含量增加，Tg提高；在实验范围内引发剂浓度和DVB/Li对SIBR中非1，4-结构含量和其，Tg影响不大。     

极性添加剂存在下铝-镍催化体系的苯乙烯-异戊二烯-丁二烯共聚物的氢化反应

采用负离子聚合法合成苯乙烯-异戊二烯-丁二烯三元共聚物( SIBR),并对其结构进行了表征;研究了结构调节剂N,N,N＇,N＇-四甲基乙二胺(TMEDA)、二乙二醇二甲醚(2 G)和四氢呋喃(THF)作外加添加剂时,对三异丁基铝(简称Al)/环烷酸镍(简称Ni)体系(A1与Ni的摩尔比为5)催化SIBR氢化反应的影响....     

Radical/Addition polymerization silicone hydrogels with simultaneous interpenetrating hydrophilic/hydrophobic networks

Transparent silicone hydrogels with interpenetrating hydrophilic/hydrophobic networks were simultaneously synthesized on the basis of the radical polymerization of the methacrylic monomer of 3‐methacryloxypropyl tris(trimethylsiloxy) silane (TRIS)/N,N‐dimethylacrylamide (DMA) and the addition polymerization of hydroxyl‐grafted polysiloxane (HPSO)/isophorone diisocyanate. The curing temperature was set at 80°C by a differential scanning calorimetry study. The polymerization process was studied by in situ Fourier transform infrared spectroscopy. The results indicate that the curing time was about 4.5 min, and the addition polymerization had a faster rate than radical polymerization. Then, the radical polymerization rate increased rapidly, and this led to instant curing. The interpenetrating polymer network (IPN) silicone hydrogels were characterized by swelling kinetics and dynamic mechanical thermal analysis. The results show that all of the hydrogels reached swelling equilibrium at about 4 h in water, and the IPN silicone hydrogels with a hydrophobic network of HPSO indicated a slower water transport than that of the copolymerization hydrogel of DMA and TRIS. The hydrophobic network was finely dispersed in the hydrophilic network, and the increasing hydrophobic network of HPSO decreased the glass‐transition temperature of the IPN silicone hydrogels. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41399.     

Reverse ATRP of acrylonitrile with diethyl 2,3-dicyano-2,3-diphenyl succinate/FeCl3/iminodiacetic acid

The reverse atom transfer radical polymerization (RATRP) technique using FeCl₃/iminodiacetic acid (IMA) complex as a catalyst was applied to the living radical polymerization of acrylonitrile (AN). A hexa-substituted ethane thermal initiator, diethyl 2,3-dicyano-2,3-diphenylsuccinate (DCDPS), was firstly used as the initiator in this iron-based RATRP system. The polymerization in N,N-dimethylformamide not only shows the best control of molecular weight and its distribution but also provides rather rapid reaction rate with the ratio of [AN]:[DCDPS]:[FeCl₃]:[IMA] at 500:1:2:4. The rate of polymerization increases with increasing the polymerization temperature and the apparent activation energy was calculated to be 49.9 kJ mol⁻¹. The polymers obtained were end-functionalized by chlorine atom, and they were used as macroinitiators to proceed the chain extension polymerization in the presence of FeCl₂/IMA catalyst system via a conventional ATRP process. The resultant polyacrylonitrile fibers were obtained with the fineness at 1.16 dtex and the tenacity at 6.01cN dtex⁻¹.     

辛烷/Span80-Tween60/丙烯酰胺/水反相微乳液聚合动力学

对辛烷／Ｓｐａｎ８０－Ｔｗｅｅｎ６０／丙烯酰胺／水反相微乳液聚合的研究表明,其反应速度快,不到３０ｍｉｎ单体转化率即可达９０％以上。聚合过程中基本不存在恒速期,聚合速率在转化率接近２０％时达到峰值后随即迅速下降。通过进一步考察单体浓度（［Ｍ］）、引发剂浓度（［Ｉ］）、乳化剂浓度（［Ｅ］）、乙酸钠浓度以及反应温度对转化率为５％时的聚合速率（Ｒｐ,５％）和最大聚合速率（Ｒｐ,ｍａｘ）以及聚合物平均相对分子质量（Ｍｖ）的影响,得到如下动力学关系式：Ｒｐ,５％∝［Ｍ］１．０２［Ｉ］０．４５［Ｅ］－０．３…     

Inline monitoring of styrene/butyl acrylate miniemulsion polymerization with attenuated total reflectance/Fourier transform infrared spectroscopy

The copolymerization of styrene/butyl acrylate in a miniemulsion was monitored inline with an attenuated total reflectance/Fourier transform infrared (ATR–FTIR) probe. ATR–FTIR spectroscopy was used to track the concentration of the monomers, thereby providing conversion and polymer composition data. Offline gravimetry and ¹H‐NMR spectroscopy were used to provide a comparison with the ATR–FTIR data. Because of inconsistent results with a univariate method, a multivariate or partial least squares calibration method using the full spectra of the reactions was selected and gave excellent results. No statistically significant differences were found between the offline and ATR–FTIR spectroscopy data coupled with multivariate statistics, and this confirmed that ATR–FTIR spectroscopy is a reliable tool for monitoring the conversion and polymer composition in miniemulsion polymerizations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 46–52, 2007     

Poly(tert-butyl acrylate-b-isobutylene-b-styrene) terpolymer from a carbocationic initiator containing a latent radical initiating site

A poly(isobutylene-b-styrene) (PIB-PS) copolymer was synthesized via quasi-living carbocationic polymerization from an initiator containing a latent site for atom transfer radical polymerization (ATRP) initiation. The initiator, 3,3,5-trimethyl-5-chlorohexyl acetate (TMCHA), was synthesized in four steps from methyl 3,3-dimethyl-4-pentenoate. The PIB block was created at −70 °C in a methylcyclohexane/methyl chloride (60:40) cosolvent system, using TiCl₄ as the catalyst, followed by sequential addition of styrene. The acetate head group of the resulting block copolymer was converted to a hydroxyl group using a strong base and subsequently esterified with 2-bromopropionyl bromide to create an initiating site for ATRP of tert-butyl acrylate, which was carried out using a Cu(I)Br/1,1,4,7,7,-pentamethyl-diethylenetriamine (PMDETA) catalyst system. The final terpolymers had compositions that were very close to theoretical.     

铬/钒双金属催化剂催化乙烯气相聚合

在实验室小试气相聚合釜中对铬/钒双金属催化剂进行乙烯聚合评价,考察了不同聚合温度和压力时催化剂的性能,研究了不同条件下催化剂的动力学行为,并将其聚合动力学曲线与用工业铬系催化剂的进行了比较。结果表明:随着聚合温度升高,用铬/钒双金属催化剂制备的聚乙烯的相对分子质量减小,熔体流动速率增大,在所研究聚合温度范围内铬/钒双金属催化剂对温度更敏感;随着聚合压力增大,催化剂活性显著提高,聚乙烯相对分子质量增加;聚合动力学曲线与铬系催化剂不同,聚合反应速率先增大再降低最后逐渐达到平稳。     

1,4-二氧六环在IBVE/Cl_2/TiCl_4聚合体系中的作用机理

<正> 1 引言 控制高分子结构、合成和制备嵌段、序列共聚物是目前聚合物合成的重要课题.在各种方法中,活性聚合是简单、经济和较通用的方法.作者曾在低于-70℃的Cl_2/TiCl_4/IBVE(异丁基乙烯基醚)/CH_2Cl_2体系中实现了活性阳离子聚合,温度高于-70℃或用其它溶剂则不能得到活性聚合物.本实验目的是研究在IBVE/Cl_2/TiCl_4体系中加入给电子添加剂DOX(1,4-二氧六环),通过DOX与增长活性链之间的相互作用,使碳阳离子稳定,探索在较高温度下或其它溶剂中的活性聚合的可能性。     

Macromolecular architectures by living and controlled/living polymerizations

The discovery of living anionic polymerization by Szwarc 50 years ago opened the way to the synthesis of model polymers. This ground-breaking discovery inspired many researchers to develop controlled/living routes for a plethora of monomers including those not compatible with anionic polymerization. These methods and their combinations serve as an arsenal for the synthesis of well-defined polymeric materials with predetermined properties and a rich variety of applications. A few representative examples of living and controlled/living methodologies for the synthesis of polymers with different macromolecular architectures are presented in this review.     

种子聚合法制备PS/PAA核壳微球的研究

设计制备了以疏水性聚苯乙烯(PS)为核、以亲水性聚丙烯酸(PAA)为壳的PS/PAA核壳结构复合微球。首先利用无皂乳液聚合法制备了亚微米级的PS微球,再以其为种子,利用种子无皂乳液聚合法制备PS/PAA核壳微球。在种子聚合阶段,选用AIBN当引发剂,经过红外光谱(IR)表征,表明当使用油溶性引发剂偶氮二异丁腈(AIBN),使其最终形成PS/PAA核壳结构微球。这种方法解决了亲水性较强的单体在以水为介质时在PS微球溶于少量的苯乙烯(St),并在引发聚合之前经过充分的吸附溶胀,可使亲水性单体AAc在PS种子微球表面聚合生成壳层,解决表面不容易直接聚合生成壳层的问题。     

Particle formation mechanism in radical polymerization in miniemulsion based on in situ surfactant formation without high energy homogenization

Conventional radical polymerization of styrene at 70 °C in aqueous miniemulsion generated using the in situ surfactant technique, without use of high energy mixing, has been investigated in detail. The surfactant potassium oleate was formed in situ by reaction between oleic acid and potassium hydroxide at the styrene/water interface. The particle formation mechanism was investigated by use of pyrene as a probe, revealing that under suitable conditions with an oil-phase initiator, particle formation occurs primarily via monomer droplet nucleation. The droplet/particle stability is however inferior to that in a typical miniemulsion generated employing ultrasonication, as manifested by a marked increase in droplet/particle size with conversion and a bimodal droplet/particle size distribution by weight. The droplet/particle stability increases with increasing amount of oleic acid, hexadecane, water, and the ratio potassium hydroxide:oleic acid, respectively.