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S. A. Kurochkin 《Polymer Science Series B》2010,52(1-2):109-117
Kinetic analysis of the scheme underlying the formation of branched and hyperbranched macro- molecules formed by living three-dimensional radical po lymerization in the pregel period makes it possible to derive some theoretical dependences relating the conditions of polymerization and the molecular-mass distribution of polymers. In this case, a polymer product constitutes a mixture of macromolecules with different degrees of branching, and the fractional weight of macromolecules with hyperbranched structure is no more than one-third with respect to the overall polymer product. 相似文献
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Ling Hong Yanjun Cui Xinling Wang Xiaozhen Tang 《Journal of polymer science. Part A, Polymer chemistry》2002,40(3):344-350
A new method for the synthesis of hyperbranched polymers involving the use of ABx macromonomers containing linear units have been investigated. Two types of novel hyperbranched polyurethanes have been synthesized by a one‐pot approach. The structures of monomers and polymers were characterized by elemental analysis, 1H NMR, 13C NMR, Fourier transform infrared spectroscopy, gel permeation chromatography, and thermogravimetric analysis. The hyperbranched polymers have been proven to be extremely soluble in a wide range of solvents. Polymer electrolytes were prepared with hyperbranched polymer, linear polymer as the host, and lithium perchlorate (LiClO4) as the ion source. Analysis of the isotherm conductivity dependence of the ion concentration indicated that these hyperbranched polymers could function as a “solvent” for the lithium salt. The conductivity increased with the increasing concentration of hyperbranched polymers in the host polymer. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 344–350, 2002 相似文献
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Heléne Magnusson Gisle Øye Wilhelm R. Glomm 《Journal of Dispersion Science and Technology》2013,34(4):547-554
A series of mesoporous aluminas have been synthesized using commercial hyperbranched polyesters of the second to fourth generation as porogens. To achieve a suitable interaction between the polymer and the aluminium source, aluminium sec‐butoxide, the terminal hydroxyl groups of the hyperbranched polymer were first reacted by succinic anhydride. The mesoporous aluminas were analyzed by nitrogen adsorption/desorption, X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). No dependence of the generation of the hyperbranched template on pore size was found in this study. Instead the pore size appears to depend on the amount of water added to the reaction mixture as well as the concentration of the hyperbranched polymer. 相似文献
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本文将超支化树脂(HBP)与UV固化粉末涂料相结合,研究了超支化树脂对该涂料的树脂体系玻璃化温度、流变性能及涂膜各项物理性能的影响.结果表明:添加改性与未改性超支化树脂都能降低树脂体系的玻璃化温度,改性超支化树脂不影响体系的流变性能及涂膜性能,未改性超支化树脂可以降低体系粘度但使涂膜性能变差. 相似文献
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近年来,单分子胶束/粒子(Unimolecular micelle:UIM)引起了人们的极大兴趣,这是由于通过对核和壳的化学设计,粒子的溶解性、生物相容性、刺激响应性、与基质的相互作用等都可得到改进,粒子还可以包裹多种客体。相对于自组装法而言,超支化聚合物法在合成UIM方面具有某些独有的特征,主要表现在:(1)UIM的尺寸主要由超支化聚合物决定,从而具有相当的可预见性;(2)可以大规模、高浓度合成UIM;(3)对聚合物的亲水性没有要求,可以利用的聚合物非常广泛,核-壳结构更为丰富;(4)产品可以以任何形式存在。本文在简要比较以自组装法和超支化聚合物法合成UIM的基础上,主要介绍了以超支化聚合物(特别是超支化聚甘油醚(PG))为支架合成各种核-壳聚合物及其应用。以长链小分子或聚合物改性的PG可以用作纳米胶囊,也可以作为纳米模板来合成各种无机粒子,而后者显示出量子限制效应和模板效应。特别地,一种全亲水壳交联的、刺激响应的粒子的合成显示了超支化聚合物法在合成复杂UIM方面的优势。总之,超支化聚合物法提供了巨大的核-壳结构分子设计空间,为合成功能集成粒子提供了更多机会。 相似文献
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Jianhua Liu Fu Zhan Qi Fu Xiangyang Zhu Wenfang Shi 《Journal of polymer science. Part A, Polymer chemistry》2008,46(22):7543-7555
A facile strategy combining free radical telomerization and polycondensation to prepare hyperbranched polymers was developed. By selecting a suitable telogen and a vinyl monomer, the product obtained by telomerization could be regarded as an ABn type monomer for preparing a hyperbranched polymer via conventional polycondensation. The principles for selecting vinyl monomers and telogens were proposed. The feed ratio of vinyl monomer to telogen was discussed in the theory. For demonstrating the strategy, methyl (meth)acrylate (MA or MMA) and 2‐mercaptoethanol were used as a vinyl monomer and a telogen, respectively. The two‐unit adduct of MA or MMA obtained after purifying was regarded as a model ABB′ monomer. The sequential transesterification demonstrated that the carboxylate group at the terminal unit has higher reactivity than that at penultimate unit because of the different substituents at the respective α‐positions, resulting in lower degree of branching (DB) of obtained polymer. As substitutes, 2‐hydroxyethyl (meth)acrylate and thioglycolic acid were used as a vinyl monomer and a telogen, respectively. The results showed that the hyperbranched polymer obtained by using pseudo one‐pot approach had moderate DB. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7543–7555, 2008 相似文献
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Xinbo Shi Ye Zhao Haiyang Gao Ling Zhang Fangming Zhu Qing Wu 《Macromolecular rapid communications》2012,33(5):374-379
A novel polymerization methodology for efficient synthesis of hyperbranched polyethylene amphiphiles by chain walking polymerization (CWP) followed by RAFT polymerization has been developed. Hyperbranched polyethylene with hydroxyl ends (HBPE‐OHs) is first synthesized via chain walking copolymerization of ethylene with 2‐hydroxyethyl acrylate with Pd‐α‐diimine catalyst. The hydroxyl groups of hyperbranched polyethylene are then converted into thiocarbonyl thio moieties by an esterification reaction with trithiocarbonate 3‐benzylsulfanylthiocarbonyl sulfanylpropionic acid (BSPA). The hyperbranched polyethylene with thiocarbonyl thio moiety ends (HBPE‐BSPAs) is used as a macro‐RAFT agent for the synthesis of hyperbranched polyethylene amphiphiles, HBPE‐PDMAEMAs, by RAFT polymerization of N,N‐dimethylaminoethyl methacrylate (DMAEMA). The resultant HBPE‐PDMAEMAs can self‐assemble to form supramolecular polymer vesicles in aqueous solution. A preliminary investigation on thermo‐ and pH‐responsive behaviors of the polymer is also reported. 相似文献
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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 总被引:1,自引:0,他引:1
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. 相似文献
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通过AB2型聚合单体4-(2-羟基乙氧基)苯甲醛二甲缩醛与B2型核分子苯甲醛二甲缩醛的缩醛转移聚合反应,反应过程中不断排出低沸点的醇,合成了具核、骨架可水解的超支化聚缩醛(HBPAs).实验表明,HBPAs的分子量,多分散性和聚合度随着核比例的改变发生明显的变化.增加核比例,聚合物的分子量,多分散性和聚合度均降低.HBPAs在弱酸性条件下,骨架发生水解,生成4-(2-羟基乙氧基)-苯甲醛.研究发现,核比例对于聚合物降解速率有明显的影响,增加核比例,聚合物的降解速率加快.这表明,通过加入核分子,可以在一定程度上调控超支化聚缩醛的结构与性能. 相似文献
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A new triphenylamine-based hyperbranched polymer with electron deficient units of oxadiazole on its side chains was successfully prepared by a modified Suzuki polycondensation with Pd(PPh3)4 as a catalyst, K2CO3 as a base, and a mixture of THF/toluene (1:1) as the solvent. The electron deficient units of oxadiazole were used to improve the electron injection and transport of the polymer. The results of the cyclic voltammetry (CV) of the polymer indicate that the HOMO and LUMO energy levels match well with the work function of the ITO/PEDOT anode and the metal cathode, respectively. Moreover, the hyperbranched polymer shows blue-emission and the hyperbranched structure effectively suppressed the formation of the aggregates/excimers in the polymer film. 相似文献
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Shuiping Li Qisheng Wu Tingting Lv Huajun Zhu Haijun Hou Qing Lin Yanbo Li Chong Cui Yuhang Guo 《Polymer Science Series B》2017,59(3):328-336
Hyperbranched polymer with epoxide-terminated group was synthesized through end-capping reaction between hyperbranched polymer with hydroxyl-terminated group and epichlorohydrin. The chemical structure of the synthesized polymer was characterized by ATR-IR and 1H NMR spectroscopy. The influence of hyperbranched polymer content on the mechanical properties and fracture toughness of epoxy/polyamide systems was investigated. The toughening mechanism was discussed basing on observing the fracture surface morphologies of epoxy/polyamide/ hyperbranched polymer system. 相似文献
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Hyperbranched polymer structures represent a class of high-functionality building blocks with excellent three-dimensional topology for the construction of highly substituted conjugated polymers. In this contribution, an efficient microwave synthesis protocol toward the synthesis of conjugated hyperbranched polymers is presented. A novel series of soluble hyperbranched polyfluorenes (PTF1-PTF3) incorporating triazatruxene moiety as the branch units with various branching degrees have thus been successfully constructed with good yields and high molecular weight via a facile “A2+B2+C3” approach. The structures of the hyperbranched polymers were confirmed by NMR and GPC. Their thermal, optical, and electrochemical properties of the hyperbranched polymers were also investigated. The results showed that introduction of triazatruxene units into the hyperbranched structure endowed the polymer with good thermal stability and highly amorphous properties. Photophysical investigation of PTFx revealed strong blue emission in both solution and solid states. Hyperbranched polymers with higher degree of branching and proper content of linear fluorene units exhibited better photophysical properties in terms of narrow emission spectra and relatively high quantum efficiency as well as improved thermal spectral stability. The triazatruxene branching unit also played a role in raising the HOMO energy levels relative to those of polyfluorenes that would help to improve the charge injection and transport properties. The incorporation of triazatruxene unit into hyperbranched polymers has thus explored an effective avenue for constructing optoelectronic polymers with improved functional characteristics. 相似文献
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Sibdas Singha Mahapatra 《Polymer Degradation and Stability》2007,92(6):947-955
A s-triazine containing hyperbranched polyamine (HBPA) has been synthesized from cyanuric chloride and aromatic diamine, 4,4′-(1,4-phenylenediisopropylidene) bis-aniline by nucleophilic displacement polymerization technique using an A2 + B3 approach with high yield (>80%). The synthesized polymer has been characterized by 1H NMR, 13C NMR, FT-IR spectroscopic studies, elemental analysis, solubility and measurement of solution viscosity. The thermogravimetric (TG) analysis and differential scanning calorimetric (DSC) studies indicate that the polymer is thermostable upto 290 °C without any decomposition and has glass transition temperature of 243 °C. The flame retardancy of the pure powder polymer and the blends with linear commercial polymers such as plasticized PVC and LDPE with this hyperbranched polymer were investigated by the measurement of limiting oxygen index (LOI) value. The results show that the polymer has self-extinguishing characteristic (LOI = 38) and acts as an effective flame retardant additive for the above linear base polymers. The synergistic effect of this hyperbranched flame retardant was observed with triphenyl phosphine oxide in the same base polymers. The flammability efficiency of the hyperbranched polyamine is also evaluated by help of thermogravimetric (TG) analysis. The heat aging and leaching in different chemical media did not influence the flame retardancy of the blends. 相似文献
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Rui Wang Wei‐Zhi Wang Gui‐Zhong Yang Tianxi Liu Junsheng Yu Yadong Jiang 《Journal of polymer science. Part A, Polymer chemistry》2008,46(3):790-802
Polyfluorene homopolymer ( P1 ) and its carbazole derivatives ( P2 – P4 ) have been prepared with good yield by Suzuki coupling polymerization. P2 is an alternating copolymer based on fluorene and carbazole; P3 is a hyperbranched polymer with carbazole derivative as the core and polyfluorene as the long arms; P4 is a hyperbranched polymer with carbazole derivative as the core and the alternating fluorene and carbazole as the long arms. These polymers show highly thermal stability, and their structures and physical properties are studied using gel permeation chromatography, 1H NMR, 13C NMR, elemental analysis, Fourier transform infrared spectroscopy, thermogravimetry, UV–vis absorption, photoluminescence, and cyclic voltammetry (CV). The influence of the incorporation of carbazole and the hyperbranched structures on the thermal, electrochemical, and electroluminescent properties has been investigated. Both carbazole addition and the hyperbranched structure increase the thermal and photoluminescent stability. The CV shows an increase of the HOMO energy levels for the derivatives, compared with polyfluorene homopolymer ( P1 ). The EL devices fabricated by these polymers exhibit pure blue‐light‐emitting with negligible low‐energy emission bands, indicating that the hyperbranched structure has a strong effect on the PLED characteristics. The results imply that incorporating carbazole into polyfluorene to form a hyperbranched structure is an efficient way to obtain highly stable blue‐light‐emitting conjugated polymers, and it is possible to adjust the property of light‐emitting polymers by the amount of carbazole derivative incorporated into the polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 790–802, 2008 相似文献
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含三苯胺单元的超支化共轭聚合物的合成、表征及应用 总被引:3,自引:1,他引:2
本实验采用Wittig方法制得了未封端和封端的超支化聚三苯胺-对苯乙烯撑型聚合物,对两种共轭聚合物进行了表征和性能测试.聚合物溶液和固体膜在紫外光照射下均发出较强的绿光.首次对这类聚合物在硝基芳烃化合物荧光猝灭能力进行了初步研究,结果表明:与未封端产物相比,封端后的超支化共轭聚合物在邻硝基甲苯(o-NT)的荧光猝灭效率上有明显提高,当o-NT浓度为21.5×10-3mol/L时,荧光猝灭效率达到97%.这类共轭聚合物不仅合成操作较为简便,猝灭效率也较高,是一种很有潜力的硝基芳烃化合物荧光检测材料. 相似文献
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由苯-1,2,4-三羧酸-1,2—酐和羟乙基哌嗪合成酰胺键、叔氨和酯键交替排列的水溶性超支化聚合物 总被引:3,自引:0,他引:3
基于官能团非等活性原理,由商品化多组分单体一步法合成了超支化聚合物. 用苯—1,2,4-三羧酸—1,2酐(BTAA)与羟乙基哌嗪(HEPZ)为原料,利用氨基和羟 基反应活性不同,制备了结构非对称超支化聚酰胺—酯.分别用红外、核磁共振确 定了所得聚合物的结构.该聚合物分子骨架中含有交替排列的酰胺键、叔氨和酯键 ,易溶于水.本合成方法原料易得、工艺简单,适合大量制备超支化聚合物. 相似文献