水溶性超支化共聚(酯-胺)的分子设计及合成

超支化聚酯是超支化聚合物中的一大类 [1～ 4 ] ,由于酯结构能在自然环境下降解 ,因而引起了许多研究者的兴趣 .Hult[1,5] ,Voit[6 ,7] 和 Kricheldorf等 [8] 在合成超支化聚酯方面做出了卓有成效的贡献 .他们用带羧基和羟基的 AB2 型单体在催化剂作用下缩合反应制得超支化聚酯 ;或先将羟基保护起来 ,再把羧基酰氯化 ,得到带酰氯的 AB2 型单体 ,经进一步缩聚得到超支化聚酯 .但用这种传统方法合成的超支化聚酯一般不溶于水 ,因而在某些领域的应用受到了限制 .本文提出了一种合成水溶性超支化聚酯的新策略 ,超支化聚酯并不是用酸与醇直接…     

新型功能性超支化聚酯的合成及表征

近年来 ,树枝状和超支化聚合物的研究受到了广泛重视 ,被视为 2 1世纪聚合物科学发展的重要方向[1] .这两种聚合物都有大量的端基 ,与相同分子量的线型聚合物相比 ,它们具有更低的粘度和更好的溶解性 .树枝状聚合物具有规整的结构 ,但合成困难 ;超支化聚合物的支化结构不完整 ,可以通过简单的一步聚合获得 ,因此 ,后者受到更广泛的重视 ,也最有可能实现工业化 [2 ,3] .通常 ,超支化聚合物是通过 ABx(x≥ 2 )型单体的缩聚合成的 ,通过改变超支化聚合物的组成、结构及对其端基进行功能修饰 ,可以制备多种具有特殊用途的新材料 ,在粘度改性剂…     

端丙烯酸酯基超支化聚(酯-胺)的结构分析及光固化

近年来 ,具有树枝状结构的超支化聚合物因其独特的物理化学性质而得到广泛关注[1,2 ] .超支化聚合物主要采用 3种途径合成 ,( 1 )ABn(n >2 )型及潜ABn 型单体的聚合 ;( 2 )由A2 与Bn 型单体直接聚合 ;( 3)先由特定的单体对原位形成ABn型中间体后再聚合 .其中后两种方法可直接采用商业化原料 ,因此更具有实用价值 .目前 ,基于途径 ( 2 )已合成出超支化聚酰胺[3 ] 、聚醚[4] 、聚酰亚胺[5] 和共轭聚合物[6] 等 ,但该途径容易生成凝胶化产物 ,通过控制反应物浓度、在凝胶点之前停止反应等 ,可得到溶解型超支化产物 .由于超支化聚合物具有低…     

超支化聚(酯-酰胺)的合成与流变改性研究

近十几年来 ,超支化聚合物因具有独特的结构和特殊的性能而受到普遍关注[1] .超支化聚合物具有低的熔体粘度 ,与线性聚合物共混可显著改善其加工流变性 ,具有商业应用潜力 .关于超支化聚合物在流变改性方面的应用已有文献报道[2～ 6] ,但目前文献中的大多数单体合成较繁琐且收率不高 ,这已成为制约超支化聚合物应用的瓶颈 ,如何以简便的途径合成超支化聚合物已成为当前研究的重点 .本文设计一条新的合成路线 ,即以 1 ,2 ,4 苯三酸酐、乙醇胺及乙酸酐为原料 ,以高的收率得到了单体N ( 2 乙酰氧基乙基 ) N ( 2′ ,4′ 二羧基苯甲酰基 )胺 (…     

两亲性全季铵盐超支化聚合物的设计与合成及主-客体超分子着色应用研究

采用高效的巯基-炔点击化学与Menschutkin季铵化反应,合成了一种带有1个叠氮基、2个炔基和2个季铵盐基团的AB2型季铵盐单体,通过核磁共振、红外光谱、质谱等方法对单体结构进行了确认.将所得单体进行点击聚合,得到全季铵盐超支化聚合物,并用端叠氮基的长链烷烃封端,得到核亲水-壳憎水的两亲性超支化聚季铵盐.研究所得两亲性超支化聚合物对染料的装载性能,结果表明所合成的带正电荷两亲性聚合物对多种带负电荷的水性染料装载效果好,平均相转移率高达95%.进一步将装载染料的主-客体超分子复合物用于聚合物制品着色,发现其对SBS及PMMA等聚合物有很好的着色效果,着色均匀且不掉色,着色的膜色泽鲜艳透明.     

AB2型β-环糊精功能单体及其水溶性超支化聚合物的合成与表征

为了得到结构确定的β-环糊精大单体并用于超支化聚合,通过对β-环糊精上6位伯羟基和2位仲羟基的多步功能化改性得到了同时含有Si—H和—CH CH2基团的AB2型β-环糊精大单体,并利用硅氢加成反应一步法合成了一种新型的水溶性超支化聚合物,其具有β-环糊精空腔和超支化空穴两种疏水单元,从而可构建出一种新颖的超分子体系.采用1H-NMR、13C-NMR、飞行时间质谱和元素分析对AB2单体及其聚合物的结构进行了表征.结果表明,单体和聚合物的结构与所设计的分子结构相符合.凝胶渗透色谱/多角度激光光散射(SEC/MALLS)联用仪测得该聚合物的数均分子量、分子量分布及特性黏数分别为36690、1.887和15.8mL/g.     

在四官能团引发剂存在下的自缩合乙烯基聚合反应制备丙烯酸酯类超支化共聚物

超支化聚合物具有特殊的结构和性能 ,可通过一步法聚合直接制得 ,具有大规模工业应用前景 .近年来 ,超支化聚合物的研究已成为高分子科学的热门课题之一[1～ 3 ] .超支化聚合物的一个主要缺点是它的分子量分布比较宽 .Ｍ櫣ｌｌｅｒ[4] 等通过理论计算指出 ,在聚合体系中加入ｆ个功能基团的分子Ｂｆ[对自缩合乙烯基聚合反应 (ＳＣＶＰ) ,Ｂｆ为ｆ个引发基的引发剂 ;对ＡＢｘ 型单体的缩聚反应 ,为有ｆ个Ｂ官能团的分子 ],可以降低超支化聚合物的分子量分布 ,这一结果已被实验证实[5～ 7] .我们用ＭｏｎｔｅＣａｒｌｏ方法模拟了在多官能团引…     

超支化聚(酯-胺)分子结构及固化涂层性能研究

近年来,颜德岳等基于A2型单体二丙烯酸酯及BB2′型单体二胺化合物合成了多种端胺基超支化聚(酯-胺),并对反应机理及聚合物结构进行了系统研究[1,2],结果表明,由于B与B′活性差异,反应首先生成AB2′型和B4′型中间体,进一步聚合得到可溶性产物.我们基于A3型单体三丙烯酸酯与B2型单体二胺化合物合成了端丙烯酸酯基超支化聚(酯-胺)[3,4].在这些体系中,由于官能团反应活性高,难以控制反应程度.另外,由于超支化聚合物不能直接用作结构材料,其在涂料、粘合剂等领域的应用多基于末端官能团的固化反应[5].但通常由于官能团在分子表面密集分布,部…     

原子转移自由基聚合合成耐热性共聚物

自 1 995年第一篇有关过渡金属催化的原子转移自由基聚合 (ＡＴＲＰ)论文发表以来 ,国内外许多研究者都纷纷开展这方面的工作 ,人们已用该法合成了各类指定结构的聚合物[1～ 6] ,选用合适的引发剂比较容易合成出具有良好加工流动性的星型和超支化聚合物[2 ,3,6] .Ｎ 取代马来酰亚胺由于其环状结构而被广泛用于自由基共聚合制备耐热性聚合物[7～ 9] ,但Ｎ 取代马来酰亚胺的引入将降低聚合物的加工流动性 ,若能实现含Ｎ 取代马来酰亚胺单体结构的可控ＡＴＲＰ共聚合 ,利用多官能团引发剂如四溴甲基苯合成出星型耐热性共聚物 ,将可望同时改善聚…     

超支化聚合物研究进展

超支化聚合物由于具有高度文化三维球状结构以及众多的端基,因此显示出与相应线型分子截然不同的性质,如低粘度、无链缠结和良好的溶解性.本文讨论了超支化聚合物的特性与表征,对合成超支化聚合物所用单体以及产物作了详细介绍,旨在引起对该领域的兴趣.     

Structural and end‐group effects on bulk and surface properties of hyperbranched poly(urea urethane)s

The hydroxy end groups of aromatic and aliphatic hyperbranched poly‐(urea urethane)s prepared with an AA* + B*B₂ one‐pot method were modified with phenylisocyanate, butylisocyanate, and stearylisocyanate. The success of the modification reaction was verified with ¹H NMR and IR spectroscopy. Linear model poly‐(urea urethane)s were prepared, too, for comparison. The bulk properties of OH functionalized hyperbranched poly(urea urethane)s, compared with those of linear analogues and modified hyperbranched poly(urea urethane)s, were studied with differential scanning calorimetry, thermogravimetric analysis, and temperature‐dependent Fourier transform infrared measurements. Transparent and smooth thin films could be prepared from all polymer samples and were examined with a light microscope, a microglider, and an atomic force microscope. The properties of the polymer surface were examined by measurements of the contact angle and zeta potential. For all samples, the properties were mainly governed by the strong interactions of the urea and urethane units within the backbone, whereas the influence of the nature of the end groups and of the branched structure was reduced in comparison with other hyperbranched polymer systems. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3376–3393, 2005     

Preparation of a bacterial polyester with carboxy groups in side chains

Unsaturated biopolyesters were produced by Pseudomonas oleovorans from two mixtures of sodium octanoate and 10-undecenoic acid (90:10 and 80:20 mol/mol) as a reserve of carbon and energy. Chemical modification of double bonds into carboxyl groups was carried out with potassium permanganate (KMnO₄). Oxidation reaction was proved by ¹H and ¹³C NMR spectroscopy. Molecular weights of modified biopolyesters were not highly affected by the oxidation reaction. Hydrophilicity was enhanced; polyester containing 25 % of repeating units pendant carboxylic acid end groups was soluble in polar solvents such as methanol, dimethylsulfoxide or a 85:15 (v/v) acetone/water mixture. Moreover, the presence of carboxy pendant groups was important with respect to the hydrolytic degradation. A fast hydrolysis was observed at pH = 11 in 24 hours for the carboxylated modified polyester containing 25 % of carboxyl groups.     

Acid chloride‐functionalized hyperbranched polyester for facile and quantitative chain‐end modification: One‐pot synthesis and structure characterization

Carboxylic acid chloride end‐functionalized all‐aromatic hyperbranched polyesters were prepared from the bulk polycondensation of the AB₂ monomer 5‐(trimethylsiloxy)isophthaloyl dichloride. The acid chloride end functionality of the hyperbranched polyester was modified in situ with methanol and yielded methyl ester ends in a one‐pot process. Chain‐end functionalization and esterification were quantitative according to both potentiometric titration and ¹H NMR analysis. The signals of ¹H and ¹³C NMR spectra of the esterified hyperbranched polyester were fully assigned from model compounds of the focal, linear, dendritic, and terminal units. The degree of branching and molecular weight averages measured by ¹H and ¹³C NMR spectroscopy and multidetector size exclusion chromatography increased systematically with increasing polymerization temperatures between 80 and 200 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2855–2867, 2002     

Synthesis of a liquid crystalline semi-ordered aromatic polyester and high-resolution solid-state 13c nmr investigation of local motions

A liquid crystalline sequence-ordered polyester was prepared from isophthalic acid and 4-hydroxyphenyl 4-hydroxybenzoate in a 1:1 mole ratio. The local motions of this polymer were investigated by high-resolution solid-state ¹³C NMR and the results were compared to data obtained on liquid crystalline or semicrystalline random terpolyesters with very similar compositions. Whereas no motions of the hydroquinone rings could be detected below the glass-transition temperature of the semi-ordered polymer, the para-hydroxybenzoic acid units exhibit a certain degree of freedom in the temperature range between 450 K and 500 K.     

Influence of hyperbranched polyesters on the surface tension of polyols

The influence of hyperbranched polyesters with different functional end groups on the surface tension of mixtures with an oligo(ester diol) was investigated. The temperature dependence of the surface tension of the pure components and of the mixtures was measured by a modified Wilhelmy balance technique. The results indicate that the surface tension of the pure hyperbranched polyesters strongly depends on the functionality of the end groups. The functionalization of the hydroxyl end groups by short alkyl chains (methyl, tert-butyl) reduced the surface tension depending on the degree of substitution. The surface tension of the mixtures with the hydroxyl-terminated hyperbranched polyester was slightly increased at higher concentrations of the hyperbranched polymer compared to the surface tension of the pure ester diol. On the other hand, the surface tension of mixtures could be considerably decreased using 1% of hyperbranched polyester polyols partially substituted with short alkyl chains. In that case, the modified hyperbranched polyesters act as surface active agents. On the molecular level, the enrichment of the modified hyperbranched polyester in the surface region was proven by X-ray photoelectron spectroscopy measurements.     

全芳型超支化聚酯的合成及端基改性

芳香聚合物;全芳型超支化聚酯的合成及端基改性     

可交联含氟聚醚醚酮的合成

聚醚醚酮 (PEEK)是一种耐热等级高、耐化学药品、耐辐射并有优异的电性能及机械性能的特种工程塑料 .由于其综合性能优异 ,PEEK在航空航天、通信、电子和机械化工等领域获得成功应用 [1] .含氟芳香聚合物以其独特的性能而成为低介电常数微电子和低损耗光波导器件极具潜力的材料 [2 ] .聚合物良好的溶解性虽对光电集成电路的加工十分重要 ,但也要满足多层化操作过程 ,还要考虑器件成型后的抗化学药品性 .因而 ,在聚合物中引入可交联组分是必要和可行的方法 .另外 ,交联后的聚合物将有更高的玻璃化转变温度 (Tg)、更好的尺寸稳定性和防开…     

Regioselective polymerization of divinyl sebacate and triols using lipase catalyst

The lipase‐catalyzed regioselective polymerization of divinyl sebacate and triols has been carried out. Immobilized lipase derived from Candida antarctica induces the polymerization of divinyl sebacate and glycerol, yielding a soluble polymer of relatively high molecular weight. NMR analysis showed that 1,3‐diglyceride is a main unit and the branching unit (triglyceride) is contained in the resulting polymer. These data indicate that the polymerization proceeds regioselectively to give the reactive polyester having a pendant hydroxy group.     

Effect of Charge and Hydrophobicity on Adsorption of Modified Starches on Polyester

Polyester fabric (poly(ethylene terephthalate)) is a hydrophobic polymer. Its hydrophobic nature can be a disadvantage for certain applications like dyeing, finishing, detergency, etc. Physical or chemical modification of the polyester to make it more hydrophilic is therefore desirable for certain performance characteristics. Surface modification of polyester to make it hydrophilic can be achieved by adsorbing polymers on the polyester surface. Starch is a commonly available, hydrophilic polymer used in many textile applications that can be used to modify polyester. However, it needs to be chemically modified so that it can adsorb on the polyester fabric and physically modify the fabric characteristics. The polymers used in this study are two different modified starches—cationic and anionic starches and mixtures of the two. The adsorption kinetics on a polyester substrate was studied. The effect of charge and hydrophobicity on adsorption was investigated. Cationic starches were shown to readily adsorb on polyester and this was attributed to electrostatic interactions. Hydrophobic substituents on the cationic moiety resulted in increased adsorption. This was attributed to the weak hydrophobic interaction between the polymer chains which could result in a more coiled polymer conformation. It is hypothesized that more starch molecules are required for surface coverage of the polyester, resulting in an increase in adsorption. Anionic starch was adsorbed on the substrate but at a slower rate than the cationic starches. It is likely that there is a H bonding between acid groups on the starch and the ester groups of the polyester. However, the anionic starch is desorbed when the polyester is placed in an aqueous medium. When a blend of cationic starch and anionic starch was used, a low concentration of anionic starch was seen to increase adsorption, indicating that the polyelectrolyte complex itself may be adsorbing on the substrate. Further increases cause a decrease in adsorption as no sites may be available on the complex for adsorption. When hydrophobic substituents are present, addition of the anionic starch causes a decrease in adsorption at all concentrations. This was attributed to the “crosslinking” between the hydrophobically modified starch and the anionic polymer.     

Solution properties of dendronized poly(hydroxy ethyl methacrylate) polymers

Four generations of dendronized polymers with a methacrylate backbone and hydroxy‐functionalized aliphatic polyester dendrons based on 2,2‐bis(methylol)propionic acid were studied in solutions by rheological measurements, dynamic light scattering, turbidimetry, and ¹H NMR self‐diffusion measurements to reveal the effect of increasing hydrophilicity and molecular size on their solution properties. The studied polymers were interesting new amphiphiles with a hydrophobic main chain and a hydrophilic shell. Evidence of aggregation upon the heating of the first‐generation polymer in an aqueous solution was obtained by dynamic light scattering and turbidimetry, reflecting the effect of the hydrophobic polymer backbone, whereas the higher generation polymers did not show aggregation upon heating. Although the dimensions of the polymers were observed to increase with increasing generation, all the polymers exhibited low viscosities and Newtonian flow behavior in both aqueous and dimethyl sulfoxide solutions. The relative viscosities of the polymers in water and dimethyl sulfoxide showed that the conformation of the polymers was somewhat more open in dimethyl sulfoxide, and this led to higher viscosities than those in water, in agreement with the ¹H NMR diffusion measurements, by which the dimensions were found to be larger for the polymers dissolved in dimethyl sulfoxide. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3674–3683, 2006