超支化聚酯在环氧树脂改性中的应用

超支化聚合物是一类具有三维树形结构的高度支化的大分子。由于其独特的结构和性能以及可实现工业化生产的潜力,超支化聚合物已经成为高分子材料领域研究的热点之一,并且得到了越来越多的关注。作为一类非常重要的超支化聚合物,超支化聚酯(HBPE)引起了研究人员的极大兴趣。目前,HBPE已经在众多领域获得应用,特别是在环氧树脂改性中的研究发展迅速。综述了HBPE作为改性剂在环氧树脂中的应用研究进展,同时对HBPE在环氧树脂和其他热固性树脂改性中的应用研究方向作了展望。     

Modifications and applications of hyperbranched aliphatic polyesters based on dimethylolpropionic acid

Over the past 16 years, hyperbranched polyesters (HBPEs) based on dimethylolpropionic acid have received much attention due to their unique structural characters, their excellent physical and chemical properties as well as their potential applications in coatings, additives, drug delivery, composites, membrane science and supermolecular chemistry. HBPEs have recently become one of the types of commercialized hyperbranched polymers, and their modifications and applications are focuses of research. This paper reviews the developments in the modifications and applications of HBPEs. Copyright © 2010 Society of Chemical Industry     

Aliphatic hyperbranched polyesters based on 2,2-bis(methylol)propionic acid—Determination of structure, solution and bulk properties

Due to their highly branched structure and the large number of functional groups hyperbranched polymers possess unique properties that make them interesting for uses in a wide variety of applications. Some of the most widely investigated hyperbranched polymers are the polyesters based on 2,2-bis(methylol)propionic acid. In this paper we present the results of characterization studies of hyperbranched polyesters based on 2,2-bis(methylol)propionic acid which show that they are very complex products with a multidimensional distribution of various properties. The influence of the synthesis conditions on the structure and molar-mass characteristics of hyperbranched polyesters as well as the findings that allow a thorough understanding of the structure-property relationships are reviewed in detail.     

Hyperbranched Polymers for Coating Applications: A Review

In the present era, hyperbranched polymers have been received much progress in the structural understanding and their unique chemical and physical properties as well as their potential applications in coatings. In a new perspective, low Volatile Organic Compounds (VOC) coatings and films with previously nonachievable properties can now be produced due to the innovation of a new class of macromolecular architecture, called hyperbranched polymers revolution. This review describes notable efforts on the synthesis of hyperbranched polymers, characterization techniques, and some of the key approaches that have been made in the application of these hyperbranched polymers in the areas of PU coatings.     

Hyperbranched polyesters with internal and exo‐presented hydrogen‐bond acidic sensor groups for surface acoustic wave sensors

Three hyperbranched aromatic polyesters carrying both internal and exo‐presented hydrogen‐bond acidic phenol, carboxylic acid, or mixed phenol/acetoxy groups were coated onto 500 MHz surface acoustic wave (SAW) sensor platforms, and sensor responses to the nerve agent simulant dimethyl methylphosphonate (DMMP) and the explosives simulant dinitrotoluene (DNT) were studied. All three hyperbranched polyesters gave strong responses to DMMP, and the hyperbranched polyester carrying carboxylic acid groups gave a particularly strong response. The hyperbranched polyester carrying phenol groups gave the best response to DNT of the three polymers studied. The DMMP and DNT responses of the three hyperbranched polyesters were also compared with hyperbranched SAW sensor polymers carrying exo‐presented phenolic sensor groups only, and also with linear SAW sensor polymers carrying phenolic sensor groups. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

New coating systems based on vinyl ether‐ and oxetane‐modified hyperbranched polyesters

A series of hyperbranched aliphatic‐aromatic polyesters has been synthesized which contain vinyl ether or oxetane functionalities as curable groups. We investigated the curing behavior of these multifunctional polymers in the presence of reactive diluents in order to analyze the possibility of their application in high solids coatings. The vinyl ether‐modified hyperbranched polyesters with a high degree of modification yield the best coatings. Furthermore, coating systems containing vinyl ether‐modified hyperbranched polyesters and triethyleneglycol divinyl ether (DVE‐3) as reactive diluent showed a better performance compared to those containing 4‐hydroxybutyl vinyl ether (HBVE). Real time FT‐IR studies revealed a high conversion of functional groups (76%) for the cationic curing with DVE‐3. On the other hand, the curing reaction of the functional hyperbranched polymers without the presence of any reactive diluent stopped at 32% conversion of functional groups due to the reduced mobility of the polymer. The vinyl ether‐modified hyperbranched polyester could be cured also radically in the presence of diethyl maleate (DEM) as reactive diluent, whereas the curing of the oxetane‐modified polyesters was very slow and incomplete in all attempts.     

Radiation curing of hyperbranched polyester resins

A research area that has obtained increasing interest during the last decade concerns improvement of macromolecular properties by changes in the macromolecular architecture. One group of these materials is dendritic polymers, which are highly branched structures exhibiting very different properties compared with linear polymers. One potential application for these polymers is as radiation curable thermoset resins. This article describes a study where the use of an aliphatic hyperbranched polyester as a base for new radiation curable thermoset resins. The hyperbranched polyesters have been characterized with respect to cure rate and final mechanical properties compared with conventional resins. It is shown that hyperbranched polyesters can be used as versatile scaffolds for various radiation curable resin structures. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 612–618, 2000     

超支化聚合物的溶液相行为与涂料应用

通过新的合成方法相继制备超支化聚酯、聚醚、聚酯酰胺及聚丙烯酸酯等,其结构越来越复杂,应用也越来越广泛.本文概述了超支化聚合物椭球型的结构特征和无序支化到可控的制备方法的发展.重点介绍了其溶液无链缠绕的流变特性和相行为研究进展,通过末端官能团的改性可改变超支化聚合物的溶解性、流变性和功能化.对其在涂料领域的应用如固化剂、...     

Dendritic Polymers – Interdisciplinary Research and Emerging Applications from Unique Structural Properties

Dendritic polymers, i.e., dendrimers and hyperbranched polymers, attract increasing attention due to their unique structures and properties. The step‐wise methodologies for the synthesis of dendrimers allow the tailoring of physical and chemical properties and thus provide a powerful tool to design dendrimers for a wide variety of applications. The complex syntheses of dendrimers often result in expensive products with limited use for large‐scale industrial applications, an area where hyperbranched polymers appear to be promising alternatives. The large body of interdisciplinary research on dendritic polymers is a guarantor for emerging applications. However, the understanding of essential fundamentals such as the phase behavior of dendritic polymer solutions is still in its infancy. Therefore, this review intends to cover the syntheses, properties, and emerging applications of dendritic polymers as well as to discuss the impact of polymer branching on the phase behavior of dendritic polymer solutions within a comprehensive thermodynamic context.     

Synthesis and application of polyethylene-based functionalized hyperbranched polymers

Polyethylene is one of the largest volume commodity polymers, with excellent physical and chemical properties. Polyethylene-based functionalized hyperbranched polymers are newly developed materials with unique structures and properties. Their architecturally complex structure – topology, composition and functionality – may be designed for different applications, with reduction of complexity and cost in preparation. This review focuses on the synthesis strategies and applications of polyethylene-based functionalized hyperbranched polymers.     

New aromatic–aliphatic hyperbranched polyesters with vinylic end groups of different length as modifiers of epoxy/anhydride thermosets

The synthesis and characterization of two new aromatic–aliphatic hyperbranched polyesters modified with long and short vinylic chains was reported. These hyperbranched polymers were used as toughening modifiers of epoxy/anhydride thermosets. The curing of mixtures of diglycidyl ether of bisphenol A and hexahydro-4-methylphtalic anhydride with different proportions of both hyperbranched polymers using N,N-benzyldimethylamine as catalyst was investigated by differential scanning calorimetry. The kinetic of curing process was established using an isoconversional integral procedure. The characterization of these materials was done by means of several thermal analysis techniques and their morphology was investigated by electron microscopy. The addition of highly branched structures led to homogeneous morphologies and a more toughening fracture of the thermosets in comparison to the neat epoxy/anhydride material. The modified thermosets presented slightly lower glass transition temperature than the unmodified one and the thermal stability barely changed by the addition of the modifiers.     

超支化聚合物改性环氧树脂的研究进展

超支化聚合物因其独特的结构和性能特点,已在众多领域得到了广泛的应用,尤其是在热固性树脂的改性中的应用,可作为热固性树脂的增韧剂。该文介绍了环氧树脂的性能特点及应用,超支化聚合物的结构及特点,着重论述了近年来超支化聚合物在改性环氧树脂力学性能、固化行为及热性能方面的研究进展,并指出了超支化聚合物在环氧树脂和其它热固性树脂改性方面的发展方向。     

核分子比例对超支化聚酯结构和涂膜性能的影响

以双季戊四醇为核,二羟甲基丙酸为单体合成了不同代数的超支化聚酯。采用了IR、GPC、13C NMR、DSC和化学滴定等方法对产物进行了表征和分析。试验结果表明聚合物具有较小的多分散性指数(拟两代超支化聚酯M—w/M—n=1.159,拟四代超支化聚酯M—w/M—n=1.028)。通过聚合物的13C NMR分析了超支化聚酯的支化度,表明在超支化聚酯中,端羟基的反应活性大于线性单元中羟基的活性。并用油酸对聚合物进行改性,研究了固含量与黏度的关系及其涂膜的性能;结果表明该树脂具有良好的成膜性和涂膜性能。     

Rheology of concentrated solutions of hyperbranched polyesters

The solution rheology of different generations of hyperbranched polyesters in N‐methyl‐2‐pyrrolidinone (NMP) solvent was examined in this study. The solutions exhibited Newtonian behavior over a wide range of polyester concentrations. Also, the relative viscosities of poly(amidoamine) (PAMAM) dendrimers in ethylenediamine were compared with those of the hyperbranched polyesters in NMP. Both types of dendritic polymers have relative viscosities that are exponential functions of their molar fraction in solution. The slopes of these relative viscosity curves show a linear relationship with respect to the generation number. PAMAM dendrimers have the greater slopes for each generation, reflecting their relatively larger intrinsic viscosity values.     

Synthesis and characterization of a thermotropic liquid crystalline hyperbranched polyester

BACKGROUND: Hyperbranched polymers have received increasing attention in the fields of medicine, homogeneous catalysis and materials science. Hydroxyl‐functional aliphatic polyesters are one of the most widely investigated families of hyperbranched polymers. The research reported here is based on the preparation of a novel hyperbranched polyester and the modification of its terminal hydroxyl groups by biphenyl mesogenic units. RESULTS: 2,2,6,6‐Tetramethylolcyclohexanol as a core and 8‐[4′‐propoxy(1,1‐biphenyl)yloxy]octanoic acid as a mesogenic unit were synthesized. A hyperbranched polyester (HPE) was synthesized in one step and subsequently substituted by reaction of its terminal hydroxyl groups with the biphenyl mesogenic units to yield a novel liquid crystalline hyperbranched polyester (HPE‐LC). The chemical structures of all compounds were confirmed using Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopy. The thermal behavior and the mesogenic properties of the biphenyl mesogenic unit and HPE‐LC were investigated using differential scanning calorimetry, polarized optical microscopy and wide‐angle X‐ray diffraction. The results demonstrated that the degree of branching of the HPE is ca 0.63. Both HPE‐LC and the biphenyl mesogenic unit exhibit mesomorphic properties, but HPE‐LC has a lower isotropic transition temperature and a wider transition temperature range than the biphenyl mesogenic unit. CONCLUSION: A novel liquid crystalline hyperbranched polyester was successfully synthesized, which exhibits mesomorphic properties. This polymer has good solubility in highly polar solvents and good thermal stability. Copyright © 2009 Society of Chemical Industry     

两亲性超支化聚合物研究进展

介绍了两亲性超支化聚合物的合成方法,利用长链烷基和聚乙二醇对超支化聚合物端基接枝改性;或者对超支化聚合物改性引入活性位点,再利用其引发乙烯基单体,通过自由基聚合、开环聚合得到两亲性超支化聚合物。阐述了不同结构的两亲性超支化聚合物在溶液中的独特性质,如核壳型单分子胶束以及不同胶束形态的聚集体。详细介绍了两亲性超支化聚合物在药物输送载体、材料改性以及染料分子的封装等领域的应用现状,指出采用新的改性技术、聚合技术制备具有特殊性能的两亲性超支化聚合物以及探索其在生物医药领域的研究为今后的主要发展方向。     

超支化聚氨酯的现状及发展动态

超支化聚合物由于其特殊的结构和由此产生的独特的物理化学性质,成为了高分子学科研究的热点之一。对超支化高分子的研究已经从合成及对物理化学性质的研究发展到分子理论研究、各种功能化以及应用方面的初步探索。本文详尽分析了超支化聚氨酯的不同合成方法,并指出了超支化聚氨酯应用研究的主要方向。     

环氧树脂改性超支化聚酯的合成及性能

以偏苯三酸酐、环氧氯丙烷及甲基丙烯酸缩水甘油酯为原料合成了超支化聚酯(HBP),再通过超支化聚合物的羧基与环氧树脂环氧基的反应得到环氧改性超支化聚合物;用GPC1、H-NMR、DSC、TGA表征了环氧改性超支化聚合物的结构和热性能;比较了不同环氧树脂用量改性前后树脂的光反应活性以及光固化涂层的耐擦洗性和硬度,测定了凝胶率-曝光时间曲线;以环氧改性超支化聚合物配制了光刻胶,在混合光源以及接触曝光的条件下,分辨率达到2~3μm,且图像十分清晰,断面整齐。环氧树脂用量为HBP羧基物质量的70%左右时,改性的超支化聚酯的光固化活性有明显提高,力学性能得到明显改进。     

Facile and efficient synthesis of hyperbranched polyesters based on renewable castor oil

Hyperbranched polyesters with thioether linkages were facilely prepared from methyl 10‐undecenoate, a castor oil‐derived renewable chemical. The monomer was obtained in excellent yield through thiol–ene click chemistry in the presence of catalytic amounts of photoinitiator under UV irradiation. Subsequent bulk polycondensation via a transesterification process catalyzed by Ti(OBu)₄, Sb₂O₃ or Zn(OAc)₂ gave hyperbranched polyesters with high molecular weights and unusual crystalline properties. The degree of branching in the range 0.45 ? 0.54 calculated from quantitative ¹³C NMR spectroscopy and low inherent viscosities of 0.16 ? 0.25 dL g^?1 strongly confirmed the hyperbranched structures of the resultant polymers. © 2012 Society of Chemical Industry     

Novel concept for low temperature curing powder coatings based on hyperbranched polyesters

The concept of using hyperbranched polymers as scaffolds for solid thermoset resin applications is de-scribed. A series of semi-crystalline methacrylate-functional aliphatic poly-esters has been synthesized and characterized for applications as solid thermoset resing, e.g., powder coating resins. The polyester resins have been crosslinked by UV irradiation producing either amorphous or semi-crystalline crosslinked films depending on the initial structure. The resins are based on hyperbranched aliphatic polyesters onto which crystalline linear aliphatic polyester chains have been grafted and end-capped with methacrylate moieties. The resins exhibit a rheological behavior suitable for low temperature curing powder coatings, i.e., films that can be readily formed and UV cured at temperatures below 80°C. Dept. of Polymer Technology, SE-100 44 Stockholm, Sweden. E-mails: matskg@polymer.kth.se. mave@polymer.kth.se, and andult@polymer.kth.se.