氟烯烃的活性/可控自由基聚合研究进展

含氟聚合物具有优异而独特的性能,主要是通过氟烯烃的聚合反应合成的。自从上世纪90年代以来,活性/可控自由基聚合反应获得极大的进展,发展了多种活性自由基聚合的方法,为聚合物的精确设计、合成提供了强有力的手段。氟烯烃的活性/可控自由基聚合反应研究始于上世纪70年代,碘转移聚合已经成功地应用于含氟热塑性弹性体的商业化生产。文献已经报道的氟烯烃活性/可控自由基聚合反应包括碘转移聚合(ITP)、烷基硼自由基聚合、原子转移自由基聚合(ATRP)和可逆加成断裂链转移聚合(RAFT)或黄原酸酯交换法(MADIX)等。通过这些方法可以制备出分子量确定、结构多样化的含氟聚合物,如嵌段、接枝和遥爪聚合物等,使含氟聚合物的应用范围得到进一步拓展。本文结合本课题组的研究工作,对氟烯烃活性/可控自由基聚合反应的研究进展进行了简要综述。     

氟硅协同改性丙烯酸树脂的合成与防污性能研究

以甲基丙烯酸十二氟庚酯(FMA)、甲基丙烯酸聚二甲基硅氧烷基酯(SMA)、甲基丙烯酸甲酯、丙烯酸正丁酯、甲基丙烯酸正丁酯和丙烯酸乙酯为共聚单体,通过溶液聚合反应合成出侧链含有机氟、有机硅的丙烯酸树脂.通过核磁共振氢谱(1H-NMR)、核磁共振氟谱(19F-NMR)、红外光谱(FTIR)对聚合物的结构进行了表征.通过扫描电镜(SEM)、接触角测试和生物评价等方法,探讨了FMA、SMA含量对树脂涂膜性能的影响.结果表明氟硅改性的丙烯酸树脂比单独含氟或含硅改性的丙烯酸树脂具有更低的表面能,而且氟硅改性的丙烯酸树脂涂膜比商业化的聚硅氧烷涂膜具有更好的防污性能.     

ATRP法合成含氟丙烯酸酯类聚合物的研究进展

含氟丙烯酸酯聚合物由于氟原子的改性作用而具有优异的表面特性,不仅稳定,具有很好的耐氧化和耐腐蚀性,而且具有较好的耐水、耐油及耐污性,可望在新材料的开发、理论研究和实际应用等方面获得广泛的应用.而原子转移自由基聚合(ATRP)又可为分子设计和合成提供很有效的途径,利用这种聚合可以获得预期结构和性能的含氟嵌段聚合物材料,充分发挥含氟元素的改性作用.本文综述了ATRP在丙烯酸氟烷基酯聚合物合成方面的应用,并介绍了国内外在此领域的研究状况.     

5,6-苯并-2-亚甲基-1,3-二氧环庚烷的活性自由基开环聚合反应

活性 (或称可控 )自由基聚合研究是目前高分子科学的研究热点之一[1～ 8] .活性自由基聚合制备的聚合物具有分子量随转化率提高而线性增加、分子量分布窄和聚合反应为一级反应动力学等特点 .自由基开环聚合所得产物体积收缩小 ,某些含有不饱和双键的螺环单体发生双开环聚合时甚至发生体积膨胀 ;开环聚合还可在聚合物主链上引入各种官能团 ,如酯基、碳酸酯基、酮基等 [9～ 12 ] .因此 ,用活性聚合的方法对自由基开环聚合的分子量和分子量分布进行控制 ,可以制备出具有各种不同结构和性能的新聚合物 . Wei等 [13] 报道了利用稳定自由基法实现…     

有机非金属盐阴离子聚合研究进展

有机非金属盐阴离子聚合是活性/可控阴离子聚合的一个重要分支。有机非金属盐阴离子聚合方法最大的特点是可以在很宽的温度范围内(-20~70℃)引发(甲基)丙烯酸酯类单体聚合,分子量分布窄,显示出可控/活性的特征。该聚合方法为分子设计和合成(甲基)丙烯酸烷基酯的均聚物、嵌段聚合物、接枝聚合物和功能性聚合物提供了有效的途径。本文综述了有机非金属盐阴离子引发剂在合成(甲基)丙烯酸酯类单体中的研究进展,包括聚合的反应机理、特点、研究现状及其前景展望。     

含有三氟乙烯基芳基醚侧基的聚丙烯酸酯的合成与表征

研究了聚丙烯酸酯侧基上引入三氟乙烯基芳基醚结构单元的方法. 首先, 合成了含有三氟乙烯基芳基醚侧基的丙烯酸酯单体, 然后通过原子转移自由基聚合实现了该单体的均聚和无规共聚, 得到了含有三氟乙烯基芳基醚侧基的聚丙烯酸酯聚合物, 聚合物的分子量分布较窄. 通过控制共聚投料比, 可以得到具有不同含量三氟乙烯基芳基醚侧基的无规共聚物.     

接枝改性PVDF基含氟聚合物

聚偏氟乙烯(PVDF基)含氟聚合物由于其独特的性能受到了广泛的关注。将功能化链段引入PVDF基含氟聚合物可以进一步提升其性能并拓展其应用领域。相较于物理共混法和直接共聚改性法,通过接枝改性法将功能化单体引入含氟聚合物的侧链具有更显著的优势,可便捷、高效地得到组成精确,结构可控的接枝共聚物。本文综述了通过活性自由基聚合(包括ATRP、SET-LRP、有机催化原子转移自由基聚合(O-ATRP)、光诱导Cu(Ⅱ)介导RDRP)和高能射线辐射(γ射线,紫外,电子束)等对PVDF基含氟聚合物功能化接枝改性的方法,并对其发展趋势以及改性聚合物的应用前景进行了展望。     

（＋）-甲基丙烯酸{2,5-双[4′-（（S）-2-甲基丁氧基）苯基]苯基}酯的合成及其螺旋选择性自由基聚合

设计合成了手性单体（＋）-甲基丙烯酸{2,5-双[4′-（（S）-2-甲基丁氧基）苯基]苯基}酯,并进行了自由基溶液聚合.相比于单体,聚合物的比旋光度有显著的同向增长,且在其圆二色光谱上对应于三联苯侧基以及酯基的吸收区域呈现明显的Cotton效应,说明其主链可能采取某一旋向占优的螺旋构象.研究了聚合条件对聚合物旋光性质的影响.结果表明,采用极性大的芳香族溶剂或增加单体浓度有利于获得旋光度大的聚合物;随聚合温度增加,聚合物旋光度先增加后减小,在80℃时聚合达到最大值.该聚合物比甲基丙烯酸三芳基甲基酯类光学活性螺旋链聚合物具有更好的化学结构稳定性和立体结构稳定性.     

ATRP法合成结构对称的双羧基聚苯乙烯及其超分子的形成

从二甲苯出发,经过溴甲基化反应、氧化反应、酯化反应和溴代反应,合成了一种四官能团的引发剂,4,6-二(溴甲基)-1,3-苯二甲酸二甲酯.用该引发剂引发苯乙烯进行原子转移自由基聚合,实验结果表明聚合反应具有活性自由基聚合的特征.通过苯乙烯的本体聚合反应获得了分子量可控、双酯基位于聚合物链中间的聚苯乙烯.经过水解反应,使聚合物中的双酯基被水解成双羧基,从而得到了结构对称的两亲性聚合物,双羧基聚苯乙烯.利用该聚合物具有分子识别的特性,与十二烷胺形成了离子键超分子化合物.此工作为超分子星形聚合物的设计合成提供了简便快捷的方法.     

可逆加成-断裂链转移活性自由基聚合的应用研究进展

可逆加成-断裂链转移(Reversible addition-fragmentation chain transfer,RAFT)自由基聚合是活性自由基聚合领域的一次突破.由于该方法具有适用单体范围广、反应条件温和以及聚合实施方法多样等优点,已成为一种有效的分子设计和材料设计手段.它不但可实现聚合物链端及链段侧基的功能化和制备特定空间拓扑结构的大分子,比如嵌段、星型、梳状及链端氨基聚合物等,还可用于修饰固体材料表面及生物大分子来赋予其特殊的功能.本文综述了RAFT技术在实际应用中的实施研究进展.     

Comparison of surface confined ATRP and SET‐LRP syntheses for a series of amino (meth)acrylate polymer brushes on silicon substrates

A series of poly(amino (meth)acrylate) brushes, poly(2‐(dimethylamino)ethyl methacrylate) (PDMAEMA), poly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA), poly(2‐(dimethylamino)ethyl acrylate) (PDMAEA), poly(2‐(tert‐butylamino)ethyl methacrylate) (PTBAEMA), has been synthesized via surface‐confined controlled/living radical polymerizations using surface‐confined initiator from silane self‐assembled monolayers (SAMs) on silicon (Si) wafer substrates. Chemical methods and efficacies for two types of living radical polymerization, atom transfer radical (ATRP) and single electron transfer (SET‐LRP), are described and contrasted for the surface confined polymerization of poly(amino (meth)acrylate)s. Effects of solvent, catalyst/ligand system, and temperature on polymerization success were examined. Chemical compositions after each reaction step were characterized with FTIR spectroscopy, contact angle goniometry, and X‐ray photoelectron spectroscopy while the SAM and polymer brush thicknesses were measured with spectroscopic ellipsometry. For the first time, this study demonstrates successful surface‐confined polymerization of a series of poly(amine (meth)acrylate) brushes from Si‐SAM substrates using a copper metal electron donor catalyst. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6552–6560, 2009     

Side‐chain ferrocene‐containing (meth)acrylate polymers: Synthesis and properties

A comprehensive investigation on the synthesis and properties of a series of ferrocene‐containing (meth)acrylate monomers and their polymers that differ in the linkers between the ferrocene unit and the backbone was carried out. The side‐chain ferrocene‐containing polymers were prepared via atom transfer radical polymerization. The kinetic studies indicated that polymerization of most monomers followed a “controlled”/living manner. The polymerization rates were affected by the vinyl monomer structures and decreased with an increase of the linker length. Methacrylate polymerization was much faster than acrylate polymerization. The optical absorption of monomers and polymers was affected by the linkers. Thermal properties of these polymers can be tuned by controlling the length of the linker between the ferrocene unit and the backbone. By increasing the length of the linker, the glass transition temperature ranged from over 100 to ?20 °C. Electrochemical properties of both monomers and polymers were characterized. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

氟碳端基聚合物合成及其表面吸附性能

综述了近十年来氟端基聚合物的合成,表征及其在表面吸附行为的研究成果。通过含有氟烷基的引发剂或终止剂在活性阴离子聚合反应或自由基聚合反应中使聚合物接上氟端基。已经成功地利用活性阴离子聚合反应合成了氟端基聚苯乙烯,通过含氟自由基引发烯类单体（如丙烯酸,乙烯硅等）可在相应聚合物链上引入氟端基,另外,聚合物的化学改性方法也可将氟基团接在聚合物链端（如氟基聚氧乙烯,氟端基聚合物具有的表面活性,当水溶液中或聚     

Synthesis and characterization of block copolymers containing poly(di(ethylene glycol) 2‐ethylhexyl ether acrylate) by reversible addition–fragmentation chain transfer polymerization

Reversible addition–fragmentation chain transfer (RAFT) polymerization has emerged as one of the important living radical polymerization techniques. Herein, we report the polymerization of di(ethylene glycol) 2‐ethylhexyl ether acrylate (DEHEA), a commercially‐available monomer consisting of an amphiphilic side chain, via RAFT by using bis(2‐propionic acid) trithiocarbonate as the chain transfer agent (CTA) and AIBN as the radical initiator, at 70 °C. The kinetics of DEHEA polymerization was also evaluated. Synthesis of well‐defined ABA triblock copolymers consisting of poly(tert‐butyl acrylate) (PtBA) or poly(octadecyl acrylate) (PODA) middle blocks were prepared from a PDEHEA macroCTA. By starting from a PtBA macroCTA, a BAB triblock copolymer with PDEHEA as the middle block was also readily prepared. These amphiphilic block copolymers with PDEHEA segments bearing unique amphiphilic side chains could potentially be used as the precursor components for construction of self‐assembled nanostructures. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5420–5430, 2007     

ATRP法合成两亲的含氟柱状刷PBIEM-g-(PAA-b-PFA)

以聚甲基丙烯酸[2-(2-溴异丁酰氧)]乙酯(PBIEM)为大分子引发剂,采用接出(grafting from)原子转移自由基聚合(ATRP)技术合成了以聚丙烯酸叔丁酯-b-聚含氟丙烯酸酯为侧链的柱状分子刷PBIEM-g-(PtBA-b-PFA).通过GPC,1H-NMR和FTIR对PBIEM-g-(PtBA-b-PFA)组成和结构进行了表征,证实ATRP过程中没有发生分子间或分子内偶合反应,制备得到可控性好的含氟嵌段共聚物刷.利用大分子链中叔丁酯基团的水解反应生成两亲的含氟柱状刷PBIEM-g-(PAA-b-PFA),原子力显微镜可直接观察到PBIEM-g-(PAA-b-PFA)特征的核壳型柱状结构,得到聚合物刷的整体长度为ln=54~72 nm.     

Light‐driven atom transfer radical polymerization on supramolecular complexes of conjugated polymers and single‐walled carbon nanotubes

Previous approaches used to decorate latently reactive conjugated polymer‐coated carbon nanotube complexes have utilized “grafting‐to” strategies. Here, we coat the carbon nanotube surface with a conjugated polymer whose side chains contain the radical initiator, α‐bromoisobutyrate, which enables atom transfer radical polymerization (ATRP) from the polymer–nanotube surface. Using light to generate Cu(I) in situ, ATRP is used to grow narrow dispersity polymer chains from the polymer–nanotube surface. We confirm the successful polymerization of (meth)acrylates from the polymer–nanotube surface using a combination of gel permeation chromatography and infrared spectroscopy. Strikingly, we demonstrate that nanotube optoelectronic properties are preserved after radical‐mediated polymer grafting using Raman spectroscopy and photoluminescence mapping. Overall, this work elucidates a method to grow narrow dispersity polymer chains from the polymer–nanotube surface using light‐driven radical chemistry, with concurrent preservation of nanotube optoelectronic properties. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2015–2020     

Synthesis of poly(2‐methoxyethyl acrylate) by single electron transfer—Degenerative transfer living radical polymerization catalyzed by Na2S2O4 in water

Living radical polymerization of 2‐methoxyethyl acrylate (MEA) was achieved by single‐electron‐transfer/degenerative transfer mediated living radical polymerization (SET‐DTLRP) in water catalyzed by sodium dithionate. The poly(2‐methoxyethyl acrylate) is an amphiphilic polymer with a hydrophobic part (polyethylene chain) and a mildly hydrophilic tail. The plots of number‐average molecular weight versus conversion and ln{[M]₀/[M]} versus time are linear, indicating a controlled polymerization. This method leads to the preparation of α,ω‐di(iodo) poly(2‐methoxyethyl acrylate)s (α,ω‐di(iodo)PMEA) macroinitiators that can be further functionalized. The molecular weight distributions were determined using a combination of three detectors (TriSEC): right‐angle light scattering (RALLS), a differential viscometer (DV) and refractive index (RI). The method studied in this work represents a possible route to prepare well‐tailored macromolecules made of 2‐methoxyethyl acrylate (biocompatible material) in an environmentally friendly reaction medium. To the best of our knowledge there is no previous report dealing with the synthesis of PMEA by any LRP approach in aqueous medium. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4454–4463, 2009     

Synthesis and thermal,optical, and mechanical properties of sequence‐controlled poly(1‐adamantyl acrylate)‐block‐poly(n‐butyl acrylate) containing polar side group

We prepared the sequence‐controlled block copolymers including poly(1‐adamantyl acrylate) (PAdA) and poly(n‐butyl acrylate) sequences as the hard and soft segments, respectively, by the organotellurium‐mediated living radical polymerization. The thermal, optical, and mechanical properties of the adamantane‐containing block copolymers with polar 2‐hydroxyethyl acrylate (HEA) and acrylic acid (AA) repeating units were investigated. The microphase‐separated structures of the block copolymers were confirmed by the differential scanning calorimetry and atomic force microscopy observations as well as dynamic mechanical measurements. The α‐ and β‐dispersions due to the main‐chain and side group molecular motions, respectively, of the hard and soft segments were observed. Their transition temperatures and activation energies increased due to the formation of intermolecular hydrogen bonding by the introduction of the HEA and AA repeating units. The effects of the hydrogen bonding on their tensile elasticity, strength, and strain were also evaluated. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2899–2910     

Effect of ligand on the synthesis of star polymers by resorcinarene‐based ATRP initiators

The effect of the steric hindrance on the initiating properties of two multifunctional resorcinarene‐based initiators in atom transfer radical polymerization (ATRP) was studied by using Cu(I)‐complexes of three multidentate amine ligands in the polymerization of tert‐butyl acrylate and methyl methacrylate. These ligands are less sterically hindered and have higher activities in the catalysis of ATRP of (meth)acrylates than 2,2′‐bipyridine. The polymerizations were faster and more controlled than with the 2,2′‐bipyridyl catalyst, but the tendency for bimolecular coupling increased. Even though the initiator was octafunctional, the resulting star polymers had only four arms. This indicates that the steric hindrance arising from the conformations of the initiators determines the structure of the polymer, but the ligand noticeably affects the controllability of the polymerization © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3349–3358, 2005     

End‐group fidelity in nitroxide‐mediated living free‐radical polymerizations

In this study, new nitroxides based on the 2,2,5‐trimethyl‐4‐phenyl‐3‐azahexane‐3‐oxy skeleton were used to examine chain‐end control during the preparation of polystyrene and poly(t‐butyl acrylate) under living free‐radical conditions. Alkoxyamine‐based initiators with a chromophore attached to either the initiating fragment or the mediating nitroxide fragment were prepared, and the extent of the incorporation of the chromophores at either the initiating end or the propagating chain end was determined. In contrast to 2,2,6,6‐tetramethyl piperidinoxy (TEMPO), the incorporation of the initiating and terminating fragment into the polymer chain was extremely high. For both poly(t‐butyl acrylate) and polystyrene with molecular weights less than or equal to 70,000, incorporations at the initiating end of greater than 97% were observed. At the terminating chain end, incorporations of greater than 95% were obtained for molecular weights less than or equal to 50,000. The level of incorporation tended to decrease slightly at higher molecular weights because of the loss of the alkoxyamine propagating unit, which had important consequences for block copolymer formation. These results clearly show that these new α‐H nitroxides could control the polymerization of vinyl monomers such as styrene and t‐butyl acrylate to an extremely high degree, comparable to anionic and atom transfer radical polymerization procedures. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4749–4763, 2000