两亲嵌段共聚物溶液内胶束形成的温度效应

合成了一系列具有两亲嵌段结构的聚（乙二醇）（PEO）一聚（丙二醇）（PPO）共聚物．利用荧光探针及示差量热法测定了共聚物水溶液的临界胶束形成温度（CMT）值．发现二嵌段共聚物（PEO－PPO）和三嵌段共聚物（PEO－PPO－PEO）有着类似的变化规律，即随共聚物分子中疏水链（PPO）长度的增大，其CMT值降低．但三嵌段共聚（PPO－PEO－PPO）则因疏水链段处于共聚物分子的两端，因而在溶液中有可能形成立体网状交联结构．此外，利用探针分子在不同极性溶剂中荧光峰值波长发生位移的现象可以对形成胶束内核的组织程度、极性大小进行估测．     

含功能化PEO嵌段的可生物降解两亲性嵌段共聚物的可控聚合及生物医用前景（摘要）

本文采用可控聚合方法合成了一系列组成可控的由含端氨基的聚环氧乙烷（PEO）亲水链段和可生物降解的聚（ε-己内酯）（PCL）疏水链段组成的两亲性嵌段共聚物PCL-b-PEO-NH2.通过共聚物端氨基的反应活性,进一步合成了含有功能性基团的PCL-b-PEO-COOH和PCL-b-PEO-RGD两嵌段共聚物及含有温敏性组分的PCL-b-PEO-b-PNIPAAm三嵌段共聚物（PNIPAAm为聚异丙基丙烯酰胺）.     

长软链段对苯二甲酸乙二酯—环氧乙烷多嵌段共聚物的组成…

合成了不同软锻段长度和不同链段含量的系列对苯二甲酸乙二酯－环氧乙烷（ＰＥＴ－ＰＥＯ）多嵌段共聚物，用ＮＭＲ质子谱测定了硬链段一，对部分溶于氯仿的ＰＥＴ－ＰＥＯ多嵌段共聚物进行了分离，并分别测定基氯仿可溶物和不溶物的硬边段一、熔融热谱和热结晶谱，揭示了ＰＥＴ－ＰＥＯ多嵌段共聚物的组成不均一性及其对软段长度和硬链段一的信赖性，进而用ＤＳＣ热谱证明了软链段和硬链段的结晶能力与ＰＥＴ－ＰＥＯ多嵌段共聚物组     

嵌段共聚物的临界条件液相色谱分离与表征

嵌段共聚物是由两种或两种以上不同性质的聚合物链段通过共价键连接形成的特殊聚合物。它可以结合构成嵌段的不同种类聚合物的性质,得到性能比较优越的功能性聚合物材料,因此越来越受到人们的重视。然而,嵌段共聚物的分离和表征一直都是一项颇具挑战性的工作。临界条件液相色谱（liquid chromatography at the critical condition,LCCC）作为一种新型的液相色谱分离技术,可以使嵌段共聚物中的某种嵌段处于“色谱不可见”（chromatographic invisible）状态,不会影响整个聚合物的保留时间,从而根据嵌段共聚物中其他嵌段长度来分离嵌段共聚物。本文介绍了LCCC分离法的分离原理与实现途径,较为系统地综述了LCCC分离表征嵌段共聚物的近期研究进展,并对该方法目前存在的问题及今后发展前景进行了探讨。     

共聚物在聚合物共混体系中的增容作用I.嵌段共聚物

随着高分子合金领域的研究发展，以共聚物作为增容剂对不相容的聚合物共混体系进行改性已得到了广泛的研究和应用。本文分为两篇，分别介绍利用嵌段共聚物、接枝共聚物和无规共聚物所做的增容改性研究。本篇着重讨论嵌段共聚物(包括两嵌段和三嵌段以及多嵌段共聚物)在聚合物共混体系中的增容作用和增容机理。     

苯乙烯—环氧乙烷嵌段共聚物的阴离子聚合与表征

用二苯甲烷钾为引发剂,阴离子聚合法合成了苯乙烯（Ｓｔ）－环氧乙烷（ＥＯ）嵌段共聚物,并用ＦＴＩＲ,＾１Ｈ－ＮＭＲ,ＳＥＣ,ＷＡＸＤ和动态粘弹谱对共聚物进行了表征。结果表明所得聚合物为分子量可控,窄分布的两嵌段共聚物。     

用SN型催化剂合成苯乙烯－丙烯嵌段共聚物的研究II．共聚物的结构表征与性能

报道用稀土化合物改性的钛系截体催化剂（ＳＮ催化剂）进行苯乙烯和丙烯顺序嵌段共聚合（Ｓｅｑｕｅｎｔｉａｌｂｌｏｃｋｃｏｐｏｌｙｍｅｒｉｚａｔｉｏｎ）的研究，通过对初生嵌段共聚产物进行溶剂萃取与分级，并用１３Ｃ－ＮＭＲ、ＷＡＸＤ．ＤＳＣ，ＤＭＡ和电子显微镜进行表征，推断共聚物为具有等规聚苯乙烯链和等规聚丙烯链段的Ａ－Ｂ型二嵌段共聚物，且各段均能结晶。发现嵌段共聚物比相应的均聚物具有较好的综合力学性能和热性能，而且对ｉＰＳ／ｉＰＰ共混具有良好的增容作用。     

用SN型催化剂合成苯乙烯—丙烯嵌段共聚物的研究Ⅱ．共聚物的结构表征与性能

报道用稀土化合物改性的钛系载体催化剂（SN催化剂）进行苯乙烯和丙烯顺序嵌段共聚合（Sequential block copolymerization) 的研究。通过对初生嵌段共聚产物进行溶剂萃取与分级，并用^13C-NMR、WAXD、DSC、DMA和电子显微镜进行表征，推断共聚物为具有等规聚苯乙烯链和等规聚丙烯链段的A－B型二嵌段共聚物，且各段均能结晶。发现嵌段共聚物比相应的均聚物具有较好的综合力学性能和热性能，而且对iPS/iPP共混具有良好的增容作用。     

嵌段共聚物自组装的研究进展

自组装是分子间通过非共价键相互作用自发组合形成的一类结构明确、稳定,同时具有某种特定功能或性能的分子聚集体或超分子结构的现象.嵌段共聚物不仅可以在本体中自组装,还能在溶液中自组装.本文综述了嵌段共聚物在溶液中自组装的规律及其主要影响因素,包括嵌段共聚物链段长度、选择性溶剂的性质、嵌段共聚物的浓度、溶液的pH值等;并介绍...     

环氧丙烷聚醚三元醇/聚乳酸嵌段共聚物的合成与性能

以低不饱和度环氧丙烷聚醚三元醇与L型及DL型丙交酯为原料, 合成了不同单体物质的量比的聚醚与聚乳酸嵌段共聚物. 采用FTIR, 1H NMR, GPC对共聚物的结构进行了表征; 用DSC, DTA对共聚物的玻璃化转变温度、熔点及热分解温度进行了研究. 结果表明, 丙交酯在聚醚多元醇端羟基的引发下发生开环反应, 得到聚环氧丙烷L型乳酸(POLLA)或聚环氧丙烷DL型乳酸(PODLA)二嵌段共聚物. POLLA二嵌段共聚物具有结晶能力, 且随着L型聚乳酸链段的增长而增强. PODLA二嵌段共聚物为非晶态聚合物. 两种共聚物的玻璃化转变温度与共聚物的组成有关, 其值介于聚醚和聚乳酸玻璃化转变温度之间. 与聚醚三元醇相比, 二嵌段共聚物的耐热性得到提高, 其热分解温度提高了30～60 ℃, 约为235～262 ℃. 共聚物的结构和组成对材料的热降解机制有很大影响. PODLA在高温区发生热氧化降解.     

Synthesis and characterization of temperature‐sensitive block‐graft PNiPAAm‐b‐(PαN3CL‐g‐alkyne) copolymers by ring‐opening polymerization and click reaction

This study synthesized thermo‐sensitive amphiphilic block‐graft PNiPAAm‐b‐(PαN₃CL‐g‐alkyne) copolymers through ring‐opening polymerization of α‐chloro‐ε‐caprolactone (αClCL) with hydroxyl‐terminated macroinitiator poly(N‐isopropylacrylamide) (PNiPAAm), substituting pendent chlorides with sodium azide. This was then used to graft various kinds of terminal alkynes moieties by means of the copper‐catalyzed Huisgen's 1,3‐dipolar cycloaddition (“click” reaction). ¹H NMR, FTIR, and gel permeation chromatography (GPC) was used to characterize these copolymers. The solubility of the block‐graft copolymers in aqueous media was investigated using turbidity measurement, revealing a lower critical solution temperature (LCST) in the polymers. These solutions showed reversible changes in optical properties: transparent below the LCST, and opaque above the LCST. The LCST values were dependant on the composition of the polymer. With critical micelle concentrations (CMCs) in the range of 2.04–9.77 mg L^?1, the block copolymers formed micelles in the aqueous phase, owing to their amphiphilic characteristics. An increase in the length of hydrophobic segments or a decrease in the length of hydrophilic segments amphiphilic block‐graft copolymers produced lower CMC values. The research verified the core‐shell structure of micelles by ¹H NMR analyses in D₂O. Transmission electron microscopy was used to analyze the morphology of the micelles, revealing a spherical structure. The average size of the micelles was in the range of 75–145 nm (blank), and 105–190 nm (with drug). High drug entrapment efficiency and drug loading content were observed in the drug micelles. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Complex macromolecular structures from stable radical containing block copolymers

A novel synthetic strategy for the synthesis of graft copolymers is reported. Block copolymers containing segments with stable nitroxyl radicals side groups were first prepared by anionic polymerization, which were then used as a precursor for the subsequent nitroxide-mediated radical polymerization (NMRP) of styrene. This way, block–graft copolymers with polystyrene side chains grafted from one of the blocks were successfully synthesized in a controlled manner. In addition, block–graft copolymers with grafted polystyrene chains and a poly(tert-butyl methacrylate) block were subjected to hydrolysis to yield the corresponding amphiphilic polymers. The structures and the molecular weight characteristics of the polymers were characterized by spectral and chromatographic analyses. The surface morphology of thus obtained polymers was also investigated by microscopic techniques. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 62–69     

Preparation and characterization of biodegradable nanoparticles based on amphiphilic poly(3-hydroxybutyrate)-poly(ethylene glycol)-poly(3-hydroxybutyrate) triblock copolymer

Amphiphilic triblock copolymers of poly(3-hydroxybutyrate)-poly(ethylene glycol)-poly(3-hydroxybutyrate) (PHB-PEG-PHB) were directly synthesized by the ring-opening copolymerization of β-butyrolactone monomer using PEG as macroinitiator. Their structure, thermal properties and crystallization were investigated by ¹H NMR, differential scanning calorimetry (DSC) and X-ray diffraction. It was found that both PHB and PEG blocks were miscible. With the increase in the PHB block length, the triblock copolymers became amorphous because amorphous PHB block remarkably depressed the crystallization of the PEG block. Biodegradable nanoparticles with core-shell structure were prepared in aqueous solution from the amphiphilic triblock copolymers, and characterized by ¹H NMR, SEM and fluorescence. The hydrophobic PHB segments formed the central solid-like core, and stabilized by the hydrophilic PEG block. The nanoparticle size was close related to the initial concentrations of the nanoparticle dispersions and the compositions of the triblock copolymers. Moreover, the PHB-PEG-PHB nanoparticles also showed good drug loading properties, which suggested that they were very suitable as delivery vehicles for hydrophobic drugs.     

Chitooligosaccharide Copolymers: Synthesis and Aqueous Self-assembly

Novel water-soluble amphiphilic graft copolymers (COS-g-PCL-b-MPEG) were synthesized by the coupling reaction between chitooligosaccharide (COS) and MPEG-b-PCL-COOH, which was synthesized via ring-opening polymerization of ε-caprolactone (CL) using MPEG as an initiator and subsequent carboxylation by succinic anhydride. The chemical composition of the graft copolymers was confirmed by ¹H-NMR spectra and FT-IR spectrometry. The thermal properties and crystallinity of the copolymers were observed by DSC and XRD measurements, which showed the existence of separate backbone and graft chain phases in the copolymer. The micellar behavior via self-assembly of the graft copolymers in aqueous solution was studied using pyrene fluorescence dye technique. AFM measurements showed that the micelles had a spherical morphology at the critical micelle concentration (CMC) and ranged in size from 20–45 nm. The amphiphilic ternary biodegradable graft copolymer endows the hydrophilic outer shell of micelles with structural and functional diversification, which might be desirable for drug delivery applications.     

Biocompatible,Hemocompatible and Antibacterial Acylated Dextran-g-polyisobutylene Graft Copolymers with Silver Nanoparticles

The novel amphiphilic acylated dextran-g-polyisobutylene(AcyDex-g-PIB) graft copolymers with different branch lengths(M_n,PIB,2600–5800 g/mol) and grafting numbers(G_N, 5–28 per 1000 Dex monosaccharide) were successfully synthesized via the nucleophilic substitution of the hydroxyl(―OH) side groups along AcyDex backbone by the living PIB-THF₄⁺ chains prepared through cationic polymerization. The crystallization of AcyDex backbone in AcyDex-g-PIB graft co...     

功能性两亲嵌段共聚物的研究进展

功能性两亲嵌段共聚物因自身独特的性质而在靶向输送、控制释放、分子识别等领域得到广泛的应用.本文对这类嵌段共聚物的合成方法、其胶束的形成机理、制备形式、表征手段以及一些常见的具有光学活性的两亲嵌段共聚物及其应用进行了综述.     

丙烯酰胺-苯乙烯双亲嵌段共聚物水溶液的表面活性及增溶性

在微乳液介质中制备了系列的丙烯酰胺 (AM)与苯乙烯 (St)的双亲嵌段共聚物 (PAM b PSt) ,用紫外分光光度法测定了共聚物的组成 ,用乌氏粘度计测定了共聚物的特性粘数 [η],并用其相对表征共聚物的分子量大小 .重点研究了双亲嵌段共聚物 (PAM b PSt)疏水链段在水溶液中的缔合行为、共聚物的表面活性及其对有机物的增溶性能 ,考察了共聚物分子组成 (疏水链段含量 )与分子量对其表面活性与增溶性能的影响规律 .研究结果表明 ,由于疏水链段的憎水性 ,PAM b PSt的分子链在水溶液表面会形成表面吸附 ,从而降低水溶液的表面张力 ;而在水溶液中 ,在疏水相互作用下 ,PAM b PSt分子链中的苯乙烯疏水链段会形成分子间或分子内的胶束 ,烃类有机物可增溶其中 ;疏水链段含量越大 ,分子量越小 ,PAM b PSt的表面活性与增溶性能越强     

两亲性嵌段聚醚酯在空气-水界面上的Langmuir单分子膜

聚醚酯是一种新型弹性材料,目前已成为工业化产品[1].对这种嵌段聚醚酯的合成和弹性行为[2]、熔体的流变性能[3]、以及纤维在拉伸状态下的聚集态结构和分子运动[4]已有一些报道.     

Self‐assembly of amphiphilic ABA random triblock copolymers in water

Self‐assembly of amphiphilic ABA random triblock copolymers in water serves as a novel approach to create unique structure micelles connected with flexible linkages. The ABA triblock copolymers consist of amphiphilic random copolymers bearing hydrophilic poly(ethylene glycol) and hydrophobic dodecyl pendants as the A segments and a hydrophilic poly(ethylene oxide) (PEO) as the middle B segment. The A block is varied in dodecyl methacrylate content of 20%–50% and degree of polymerization (DP) of 100‐200. By controlling the composition and DP of the A block, various architectures can be tailor‐made as micelles in water: PEO‐linked double core unimer micelles, PEO‐looped unimer or dimer micelles, and multichain micelles. Those PEO‐linked or looped micelles further exhibit thermoresponsive solubility in water. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 313–321     

P(MMA-co-MAh)-g-mPEG的合成及环境敏感性

采用偶合接枝法在甲基丙烯酸甲酯(MMA)和马来酸酐(MAh)无规共聚物上接枝不同含量的聚乙二醇单甲醚(mPEG), 合成具有pH敏感和温度敏感的两亲接枝共聚物P(MMA-co-MAh)-g-mPEG, 并对其进行了红外光谱和核磁共振波谱表征. 通过紫外-可见分光光度计测量了接枝共聚物水溶液的透光率, 结果表明, 接枝聚合物的水溶液呈现低临界溶解温度(LCST), 其LCST值对环境pH值和无机盐等因素敏感, 并可通过控制亲水侧链含量来调节.