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双语推荐：三嵌段共聚物

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RAFT聚合具有反应条件温和，对单体纯度和环境的要求相对较低等优势，近年来通过RAFT方法制备嵌段共聚物已经受到了高分子化学领域研究者的广泛关注。简要介绍了近10年来通过 RAFT 方法制备嵌段共聚物所常用的 RAFT试剂和单体的研究进展，主要介绍了近10年来线型两嵌段、三嵌段共聚物和星型嵌段共聚物的RAFT聚合及应用。
RAFT polymerization hasmanyadvantages, such asmild reaction conditions, relatively low requirements forpurity of the monomer,andso on. In recent years, preparation of block copolymers by RAFT has been paid widespread attention in the field of polymer chemistry. Inthis article, RAFT agents and monomers were introduced. The recent research progress in preparation of block copolymers by RAFT was discussed, and RAFT polymerization and application of linear diblock, triblock and star copolymerswere introduced.

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采用耗散粒子动力学方法模拟研究了rod-coil-rod三嵌段共聚物在稀溶液中的聚集行为.分别考察了rod-coil嵌段的相互作用、溶剂性质、共聚物浓度以及coil嵌段长度对聚集体形貌的影响.模拟结果发现,随着rod-coil相互排斥作用的增加,共聚物由球形转变成洋葱状、笼形和柱状结构.随着coil嵌段疏水性的增加,笼形转变成洋葱状和补丁状结构.给出了聚集体形貌随共聚物浓度和coil长度变化的相图.当浓度较小和coil嵌段较长时,共聚物形成笼状聚集体,反之,则有利于洋葱状结构的形成.
The aggregate morphology of rod-coil-rod copolymers in a dilute solution was investigated by dissipative particle dynamics simulations. The influences of the mutual compatibility between rod and coil blocks, the solvent property, the coil length, and the copolymer concentration on the aggregate structure were studied in detail. The simulation results show that the increase of the mutual compatibility between rod and coil blocks induces transformation of the aggregate morphology from spherical, to onion-like, to cage-like, and ultimately to cylindrical. With the increase in the hydrophobicity of the coil block, the cage-like aggregate changes into an onion-like aggregate, then a patchy aggregate, and then an inverted onion-like aggregate. Final y, a phase diagram of the rod-coil-rod triblock copolymers as a function of the coil length and the copolymer concentration is presented. It shows that cage aggregates are easily formed when the coil length is long and the concentration is relati

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基于蠕虫状链模型和高斯链模型的自洽场理论研究了对称柔性-半刚性-柔性三嵌段共聚物在二维空间中的相行为.在设定的计算参数下得到了多种该体系的热力学平衡态相结构,包括各向同性Isotropic相、各向异性Nematic相、层状Smectic-C相、四角柱状相、斜交型冰球状相、断层型冰球状相和稻粒状结构.与刚-柔两嵌段共聚物相比,对称柔性-半刚性-柔性三嵌段共聚物更容易形成Smectic-C相.在柱状相结构中,在柔性嵌段的牵伸作用下半刚性嵌段在液晶相区中相互穿插,从而形成菱形和长方形液晶相区.当取向相互作用较强时,半刚性嵌段沿长方形液晶相区的短边方向出现2次折叠.为进一步探索高分子折叠现象产生的原因以及液晶成核机理奠定了理论基础.
The self-assembly of symmetric coil-semiflexible-coil triblock copolymers in 2 D space was investi-gated using self-consistent field theory(SCFT). The semiflexible block and the coil block of the copolymers were described as wormlike chain model, and Gaussian chain model, respectively. A highly accurate and effi-cient operator splitting pseudospectral algorithm combined with SPHEREPACK software package was employed to solve modified diffusion equations for the propagators of wormlike chains. The anisotropic interactions favoring the parallel alignment between semiflexible segments was described by Maier-Saupe orientational inter-actions μN , and the enthalpic interactions between coil and semiflexible segments were described by isotro-pic Flory-Huggins interactions χN . By increasing χN and volume fraction of the coil blocks, a phase dia-gram including isotropic, nematic, smectic-C, tetragonal cylinders, oblique pucks, broken lamella pucks and rice-shaped phase for symmetr

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以三枝化低不饱和度聚环氧丙烷(PPO)引发D-丙交酯(D-LA)逐步开环聚合,合成了三枝化聚环氧丙烷-聚右旋乳酸(PPO-PDLA)共聚物.用辛酸亚锡Sn(Oct)2与PPO-PDLA端羟基反应进行Sn(Oct)封端,制备了三枝化PPO-PDLA-Sn(Oct)预聚物.再于130℃下,以其作为大分子引发剂与L-丙交酯(L-LA)开环聚合,合成了分子量105的三枝化PPO-PDLA-PLLA嵌段共聚物.活性端基的引入,降低了聚合反应温度,从而降低了聚合中的酯交换或热降解反应发生的概率.实现了高分子量PPO-PDLA-PLLA嵌段共聚物的合成.结构测试结果表明,合成的嵌段共聚物具有分子结构易控及立构规整度高等特点.在结晶-熔融-再结晶重复热处理下,三枝化PPO-PDLA-PLLA嵌段共聚物仅发生立构复合聚乳酸结晶,且结晶能力稳定.
Three-arm poly(propylene oxide) (PPO) was used as a macroinitiator for the ring-opening poly-merization(ROP) of D-lactide to obtain three-arm poly( propylene oxide)-block-poly(D-lactic acid) ( PPO-PDLA). PPO-PDLA copolymer was then reacted with stannous octoate [Sn(Oct) 2 ] to obtain Sn(Oct) end-capped PPO-PDLA[PPO-PDLA-Sn(Oct)]. The PPO-PDLA-Sn(Oct) can be used as an efficient macroinitia-tor for the ROP of L-lactide to synthesize three-arm PPO-PDLA-PLLA at 130 ℃, which reduces the occurrence of hydrolysis and transesterification reaction. PPO-PDLA-PLLA copolymers with high molecular weight were synthesized by this novel and simple method. The results show that the composite of PPO-PDLA-PLLA can be easily tuned by controlling the feed ratio of L-lactide and D-lactide, and the stereoregularity of PPO-PDLA-PLLA is high. Moreover, the stereocomplexes of PPO-PDLA-PLLA can survive melting to reform the stereo-complex crystallites.

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以S-十二烷基-S’-（α，α’-二甲基-α’’-乙酸）-三硫代碳酸酯（ DDMAT）为链转移剂，通过可逆加成-断裂链转移自由基聚合（ RAFT）方法制备了窄分布的聚2-乙烯基吡啶。再以该聚合物为大分子链转移剂，引发苯乙烯的RAFT聚合，得到聚2-乙烯基吡啶-b-聚苯乙烯（ P2VP-b-PS）的两嵌段共聚物。以P2VP-b-PS为RAFT试剂，合成聚2-乙烯基吡啶-b-聚苯乙烯-b-聚异戊二烯（ P2VP-b-PS-b-PI）的三嵌段共聚物。运用1 H NMR、IR 和凝胶渗透色谱（ GPC）等技术对产物的结构和分子量及分子量分布进行表征，采用原子力显微镜（ AFM）观察三嵌段共聚物薄膜的微相分离结构。结果表明，所得三嵌段共聚物P2VP72-b-PS136-b-PI300分子量分布较窄（PDI=1.69），合成过程具有活性/可控聚合特征，聚合物薄膜经溶剂退火处理后出现了明显的微观相分离结构。
Macro-RAFT agent,poly(2-vinyl pyridine)were synthesized by reversible addition-fragmenta-tion chain transfer( RAFT)polymerization using S-dodecyl-S’-(α,α’-dimethyl-α’’-acetic acid)-tri-thiocarbonate as the chain transfer agent. Poly(2-vinyl pyridine)-b-poly( styrene)( P2VP-b-PS)diblock copolymers were synthesized using styrene as monomer and the macro-RAFT agent as the chain transfer a-gent. Then,poly(2-vinyl pyridine)-b-poly(styrene)-b-poly(isoprene)(P2VP-b-PS-b-PI)triblock copol-ymers were synthesized using isoprene as monomer and the P2VP-b-PS as the chain transfer agent. The molecular structure and molecular weight of the products were characterized by 1 H NMR,IR and GPC. The results indicate that RAFT is a successful access to the triblock copolymer P2 VP76-b-PS160-b-PI300 with narrow molecular weight distribution(PDI=1. 69). The film from P2VP72-b-PS136-b-PI300,character-ized by AFM,has an obvious microphase structure after solvent annealing.

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采用开环聚合(ROP)和原子转移自由基聚合(ATRP)的方法合成了具有多重敏感性的聚乙二醇单甲醚-聚己内酯-聚甲基丙烯酸二乙氨基乙酯(mPEG-b-PCL-b-PDEAEMA)三嵌段共聚物,利用傅里叶变换红外光谱(FTIR)、核磁共振(NMR)和凝胶渗透色谱(GPC)对嵌段共聚物的结构及分子量进行了表征,改变投料比可有效调控各嵌段长度,所得共聚物的分子量分布均保持在1.3左右;其自组装后改变体系的pH、温度和CO2加入量可以有效控制聚集体的粒径大小,随CO2加入量的增加,粒径由238nm增大到538nm,而通入N2后其粒径大小恢复原状;对聚集体进行载药性能研究,发现CO2的加入可提高载药量及包封率,在释放阶段降低体系的pH或通入CO2可增加药物的释放速率和释放量。
In this paper, a novel multistimuli-responsive triblock copolymer poly ( ethyleneglycol )-block-poly (ε-caprolactone )-block-poly( N,N-Diethylaminoethyl methacrylate) ( mPEG-PCL-PDEAEMA) was synthesized by ROP and ATRP. The structure and molecular weight of the triblock copolymer were characterized by flourier transform infrared(FTIR),nuclear magnetic resonance (NMR)and gel permeation chromatography(GPC). The length of chain segment could be controlled by changing feed ratio and the molecular weight distribution remained at 1. 3;After self-assemble,aggregates diameter could be controlled by pH,CO2 and tempera-ture. The diameter increased from 238nm to 538nm with increasing the amount of CO2 and could recover by purging with N2. The re-sults of drug loading property experiment showed that purging with CO2 can increase the drug loading and encapsulation efficiency, in the release stage,reduce the pH and purging with CO2 can increase drug release rate and release amount.

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利用原子转移自由基聚合的方法合成了新型三嵌段共聚物聚（氧化乙烯）甲基醚-b-聚丙烯酸-b-聚[6-（4-甲氧基偶氮苯-4′-氧基）己基甲基丙烯酸]，通过透射电子显微镜、扫描电子显微镜、激光光散射和紫外-可见光光谱研究了该共聚物在水中的自组装行为及其 pH 值和光响应性。研究发现该共聚物可自组装形成囊泡。在 pH 值小于3．4时，胶束粒径随着 pH 值的减小而急剧增大；pH 值大于3．4时，粒径无明显变化。在偏振光的照射下，聚集体会随着照射时间的延长而拉长。
A new triblock copolymer poly(ethylene oxide)monomethyl ether-b-poly(acrylic aid)-b-poly[6-4-methoxy-azobenzene-4′-oxy)hexyl methylacrylate]was synthesized by the atom transfer radical polymerization (ATRP)method.The self-assembly behaviors in aqueous media,pH sensitive and photo-sensitive properties of this copolymer were studied by the means of transmis-sion electron microscopy (TEM),scanning electron microscopy (SEM),laser light scattering (LLS)and UV-Vis spectropho-tometer.It is found that the polymer can self-assemble into vesicle structure.With decreasing the pH value,the particle size of the aggregates increases sharply obviously bigger when pH 3.4.Upon irradiation with polarized light,the aggregates are elongated with increasing the irradiation time.

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以酚锂作为副反应抑制剂,以正丁基锂或1,1-二苯基乙烯盖帽的正丁基锂为引发剂,通过顺次添加单体的方法,合成了结构明确的聚异戊二烯-b-聚甲基丙烯酸甲酯(PI-b-PMMA)和聚甲基丙烯酸正丁酯-b-聚甲基丙烯酸甲酯(PBMA-b-PMMA)2种嵌段聚合物.嵌段聚合反应中甲基丙烯酸甲酯(MMA)的转化率均高于90%,通过核磁图谱计算的链节摩尔比与理论设计值吻合.PI-b-PMMA和PBMA-b-PMMA的分子量分别达到4×104和1.6×104.在环己烷中,通过顺次添加单体的方法,合成了结构明确的聚苯乙烯-b-聚异戊二烯-b-聚甲基丙烯酸甲酯(PS-b-PI-b-PMMA)三嵌段共聚物,各单体的转化率均达到100%,并且产物中的链节摩尔比和理论设计值一致,最终产物的分子量达到7.4×104,分子量分布仅为1.28,为极性三嵌段热塑性弹性体以及有机玻璃透明增韧剂的工业化奠定了基础.
Well-defined block copolymers polyisoprene-b-poly( methyl methacrylate) ( PI-b-PMMA) and poly ( butyl methacrylate )-b-poly ( methyl methacrylate ) ( PBMA-b-PMMA were synthesized in THF initiated by n-BuLi and DPHLi with the addition of P-Complex. The polymerizations were carried out under the conditions which could be achieved in industry through adding monomers by sequence. The conversion of MMA was higher than 90% both in PI-b-PMMA and PBMA-b-PMMA, and the molar ratios of each segment in block copolymers detected by 1 H NMR fit to those calculated. The Mn of PI-b-PMMA and PBMA-b-PMMA were 4. 0×104 and 1. 6 × 104, respectively. Well-defined triblock polymer PS-b-PI-b-PMMA was synthesized in cyclohexane under the condition which could be achieved in industry. The conversions of monomers were all completed, and the molar ratio in the final triblock polymer was consistent to the one calculated. The final Mn was 7. 4×104, and the molecular weight distribution(MWD) was only 1. 28.

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橡胶沥青混合料在减薄路面、延长路面使用寿命、延缓反射裂缝、减轻行车噪声等方面具有独特的优势。通过使用美国X公司研制的复合型胶粉改性沥青胶浆(A),并对A沥青混合料与苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS)改性沥青混合料的低温性能进行了对比研究,结果表明其低温抗裂性能优于SBS改性沥青混合料。
Asphalt-rubber mixture have unique advantages in reducing pavement thickness,extending lifetime of pavement,delaying reflection crack,decreasing traffic noise and so on.The asphalt-rubber has been used,which is a kind of mastic and made up of rubber powder and asphalt (A)that bought from US X company.Comparing the low-temper-ature performance of A modified asphalt mixture with the styrene-butadiene-styrene (SBS)modified asphalt mixture. Results show that its low temperature crack resistance performance is superior to the SBS modified asphalt mixture.

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以三硫代碳酸二（α,α′-二甲基-α-乙酸）酯（BDATC）为链转移剂，以苯乙烯、马来酸酐、丙烯酸为原料，通过可逆加成-断裂链转移（RAFT）合成了双亲嵌段共聚物 PSt-b-P(St-alt-MA)-b-PAA。通过选择性溶剂 N,N-二甲基甲酰胺（DMF）诱导聚合物进行自组装，利用紫外-可见光光度仪、纳米激光粒度仪详细研究了共聚物中亲疏水嵌段长度、初始浓度、体系pH值对聚合物自组装行为的影响。通过化学交联的方法制备得到了聚合物交联胶束，利用透射电镜表征了形貌与尺寸，研究明确了其形状和尺寸的稳定性。结果表明，上述因素均会影响共聚物的自组装行为和自组装胶束的形态，经乙二胺交联得到的交联自组装胶束平均粒径为145.4nm，并具有良好的形状和尺寸稳定性。
Amphiphilic block copolymer PSt-b-P(St-alt-MA)-b-PAA was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using S,S′-bis(R,R′-dimethyl-α′′-acetic acid)-trithiocarbonate as RAFT agent and styrene,maleic anhydride,acrylic acid as monomers. The self-assembled micelles of PSt-b-P(St-alt-MA)-b-PAA were induced by selective solvent dimethylfomamide. The effects of block length,initial concentration and pH on the self-assembled micelles were investigated through ultra-violet and visible spectrophotometer and laser particle size analyzer. The crosslinked micelles fabricated by chemical crosslinking had stable morphology and diameter as characterized with transmission electron microscope. Block length,initial concentration and pH would affect self-assembly behavior of copolymer and morphology of self-assembled micelle. The micelles crosslinked by ethylenediamine with average particle diameter of 145.5nm had stable morphology and size.

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