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利用本体聚合方法,采用辛酸亚锡为催化剂,四氨基苯基卟啉为引发剂,引发丙交酯开环聚合,制备四臂星型聚乳酸功能高分子材料.采用1 H-NMR,FTIR,GPC等对星型聚合物的分子结构、分子量及其分布等进行了研究.利用溶液浇铸成膜方法,制备了聚乳酸薄膜材料;并利用XRD方法,研究了聚乳酸薄膜的结构.研究表明,利用四氨基苯基卟啉为引发剂,合成了以卟啉为核的四臂星型聚合物,其溶液浇铸薄膜具有正交晶系α晶型结构,而线型聚乳酸呈非晶态结构.利用紫外可见吸收光谱研究了星型聚乳酸的光谱性质,结果表明合成聚合物具有锡卟啉的光学特性. 相似文献
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<正> 随着生物工程高技术的发展,功能高分子微球作为一类新的功能高分子材料已得到十分广泛的应用。然而关于最难以合成的粒径在微米级、粒度分布窄的高分子微球合成的报道至今仍很少。本文报道了用相分离法(即静止的分散聚合法)合成含有DEAE基团的高分子微球的研究。探讨了单体、交联剂、引发剂及聚合温度、聚合时间等聚合条件对生成微球的影响。相分离聚合法的特点是利用了随着在聚合过程中单体的逐渐聚合,分子量长大,聚合体与反应体系间相容性变差而最终分相成球的原理,因而所形成的微球粒度圆,粒径比较均一。与一般的分散聚合法相比不仅生成微球的粒径较大,且不需要搅拌,使反应装置得以简化。 相似文献
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二、聚合反应与共聚合聚合反应与共聚合反应一直是高分子合成与改性的重要内容与手段,近年仍有重要发展。下面就自由基聚合、共聚合、正负离子聚合等方面的研究概况进行简要地阐述。1.自由基聚合近年的研究主要在开发含功能基的烯类单体、新型自由基引发体系和引发机理、聚合动力学尤其高转化的聚合动力学等。李笃信等研究了 N-乙烯基咔唑在 znO 为分散 相似文献
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活性 (或称可控 )自由基聚合研究是目前高分子科学的研究热点之一[1~ 8] .活性自由基聚合制备的聚合物具有分子量随转化率提高而线性增加、分子量分布窄和聚合反应为一级反应动力学等特点 .自由基开环聚合所得产物体积收缩小 ,某些含有不饱和双键的螺环单体发生双开环聚合时甚至发生体积膨胀 ;开环聚合还可在聚合物主链上引入各种官能团 ,如酯基、碳酸酯基、酮基等 [9~ 12 ] .因此 ,用活性聚合的方法对自由基开环聚合的分子量和分子量分布进行控制 ,可以制备出具有各种不同结构和性能的新聚合物 . Wei等 [13] 报道了利用稳定自由基法实现… 相似文献
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21世纪的高分子化学展望 总被引:18,自引:0,他引:18
对于21世纪高分子科学的展望大致如下:21世纪的特征是能源、材料和环保与健康(或称绿色)。作为材料领域中极其重要的部分,21世纪对高分子材料在质量方面都有要求,大致可分二个方面同是通过控制聚合而得均匀高分子,其分子量概念不再是各种长短不齐高分子链的平均分子量;二是绿色高分子与绿色反应,前者主要是指生物高分子,对环境稳定高分子则将进行回收与重复使用;所谓绿色反应指所有高分子与相应单体的合成方法都必须 相似文献
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遥爪低聚物合成的进展 总被引:2,自引:0,他引:2
简要叙述近年来遥爪低聚物合成的发展,包括自由基聚合,阳离子聚合,基团转移聚合,开环聚合等,利用遥爪低聚物人们可按不同用途对高分子材料提出的性能要求进行聚合物的分子设计。 相似文献
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Jozef Lustoň Juraj Kronek Angela Kleinová Ivica Janigová Helena Valentová Jan Nedbal 《Journal of polymer science. Part A, Polymer chemistry》2012,50(19):3936-3943
A monomer of the AB‐type and a bifunctional comonomer of the AA‐type containing two 2‐oxazoline rings and a biphenyl structural unit were prepared from the corresponding carboxylic acids via their esterification and subsequent amidation with an aminoalcohol. The cyclization of an amide to 2‐oxazoline structure was achieved by treatment with thionyl chloride followed by liberation of the free base with sodium hydrocarbonate in an aqueous solution. The prepared monomers were used for the polyaddition polymerization of the AB‐type monomer having a 2‐oxazoline and phenol group bound on adjacent rings of the biphenyl structure in solution. The monomer of the AA‐type was used for AA+BB‐type polyaddition reactions with aliphatic dicarboxylic acids. Both types of polymerizations have been performed in melt and in solution. The structures of the polymers were determined, and the thermal properties of the polymers were evaluated. Liquid‐crystalline (LC) structures of the prepared polymers were observed by DSC measurements and optical microscopy. The polyaddition reactions of the monomers containing a 2‐oxazoline ring and a biphenyl unit represent a new efficient way for the preparation of a biphenyl unit containing poly(ether amide)s and poly(ester amide)s. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
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Atsushi Sudo Takaaki Hamaguchi Naoto Aoyagi Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2013,51(2):318-326
A new trithiocarbonate 1 bearing two hydroxyl moieties was synthesized and employed as a RAFT agent for radical polymerization of vinyl monomers. 1 mediated RAFT polymerizations of styrene and ethyl acrylate to give the corresponding polymers with predictable molecular weights and narrow molecular weight distributions. Structural analyses of the polymers with NMR and MALDI‐TOF mass techniques revealed that they were telechelic ones, of which both chain ends were endowed with hydroxyl groups inherited from trithiocarbonate 1 . Usefulness of these telechelic polymers as polymeric diol‐type building blocks was demonstrated in their polyaddition with diisocyanates, which gave the corresponding polyurethanes. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
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Akira Makino Shiro Kobayashi 《Journal of polymer science. Part A, Polymer chemistry》2010,48(6):1251-1270
Chemistry of 2‐oxazolines is involved in the polymer synthesis fields of cationic ring‐opening polymerization (CROP) and enzymatic ring‐opening polyaddition (EROPA), although both polymerizations look like a quite different class of reaction. The key for the polymerization to proceed is combination of the catalyst (initiator) and the design of monomers. This article describes recent developments in polymer synthesis via these two kinds of polymerizations to afford various functional polymers having completely different structures, poly(N‐acylethylenimine)s via CROP and 2‐amino‐2‐deoxy sugar unit‐containing oligo and polysaccharides via EROPA, respectively. From the viewpoint of reaction mode, an acid‐catalyzed ring‐opening polyaddition (ROPA) is considered to be a crossing where CROP and EROPA meet. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1251–1270, 2010 相似文献
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Soluble Hf-containing polymers are significant processable precursors for the fabrication of ultra-high temperature ceramics. In this work, cyclic Hf-Schiff base polymers were synthesized via direct polymerization of hafnium alkoxide and bis-salen monomers. The defined structure and molecular weight of the polymers were characterized by NMR spectroscopy, gel permeation chromatography and MALDI-TOF mass spectroscopy. The feed ratio of monomers regulated the molecular weight and solubility of the polymers. This synthetic strategy features simple operation under ambient conditions, efficient reaction with high yield and cyclic polymers as the main products. The Hf-Schiff base polymers were converted to HfC/C materials after pyrolysis under argon at 1600 °C, which was identified by XRD measurements, elemental analyses and Raman spectroscopy. This work will inspire more precise and efficient synthesis and applications of metallopolymers. 相似文献
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Yanni Xia Yue Sun Ziheng Liu Chengjian Zhang Xinghong Zhang 《Angewandte Chemie (International ed. in English)》2023,62(37):e202306731
The facile synthesis of chemically recyclable polymers derived from sustainable feedstocks presents enormous challenges. Here, we develop a novel, modular, and efficient click reaction for connecting primary, secondary, or tertiary alcohols with activated alkenes via a bridge molecule of carbonyl sulfide (COS). The click reaction is successfully applied to synthesize a series of recyclable polymers by the step polyaddition of diols, diacrylates, and COS. Diols and diacrylates are common chemicals and can be produced from biorenewable sources, and COS is released as the industrial waste. In addition to sustainable monomers, the approach is atom-economical, wide in scope, metal-free, and performed under mild conditions, affording unprecedented polymers with nearly quantitative yields. The produced polymers also possess predesigned and widely tunable structure owing to the versatility of our method and the broad variety of monomers. The in-chain thiocarbonate and ester polar groups can play as breakpoints, allowing these polymers to be easily recycled. Overall, the polymers have broad prospects for green materials given their facile synthesis, readily available feedstocks, desirable performance, and chemical recyclability. 相似文献
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Weiping Gan Xiaosong Cao Yi Shi Haifeng Gao 《Journal of polymer science. Part A, Polymer chemistry》2020,58(1):84-90
This article reports a chain-growth coupling polymerization of AB difunctional monomer via copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction for synthesis of star polymers. Unlike our previously reported CuAAC polymerization of AB n (n ≥ 2) monomers that spontaneously demonstrated a chain-growth mechanism in synthesis of hyperbranched polymer, the homopolymerization of AB monomer showed a common but less desired step-growth mechanism as the triazole groups aligned in a linear chain could not effectively confine the Cu catalyst in the polymer species. In contrast, the use of polytriazole-based core molecules that contained multiple azido groups successfully switched the polymerization of AB monomers into chain-growth mechanism and produced 3-arm star polymers and multi-arm hyperstar polymers with linear increase of polymer molecular weight with conversion and narrow molecular weight distribution, for example, Mw/Mn ~ 1.05. When acid-degradable hyperbranched polymeric core was used, the obtained hyperstar polymers could be easily degraded under acidic environment, producing linear degraded arms with defined polydispersity. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 84–90 相似文献
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Guan Z 《Journal of the American Chemical Society》2002,124(20):5616-5617
A novel approach was demonstrated for the synthesis of hyperbranched polymers by direct free radical polymerization of divinyl monomers controlled by a cobalt chain transfer catalyst (1). By controlling the competition between propagation and chain transfer with 1, the free radical polymerization of ethylene glycol dimethacrylate (3) afforded soluble hyperbranched polymers in one pot. The structure of the hyperbranched polymers was confirmed by (1)H and (13)C NMR. The molecular weight and intrinsic viscosity of the hyperbranched polymers were measured by matrix-assisted laser desorption ionization (MALDI) mass spectrometry and size exclusion chromatography (SEC) equipped with triple detectors. The intrinsic viscosities of the hyperbranched polymers are much lower than those of their linear analogues and do not show molecular weight dependence. The unique structure and properties of these hyperbranched polymers combined with the commercial availability of many divinyl monomers and the robustness of free radical polymerization make this new approach attractive for the preparation of new functional materials. 相似文献
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Ruoyu Li Prof. Zesheng An 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22442-22448
Achieving well-defined polymers with ultrahigh molecular weight (UHMW) is an enduring pursuit in the field of reversible deactivation radical polymerization. Synthetic protocols have been successfully developed to achieve UHMWs with low dispersities exclusively from conjugated monomers while no polymerization of unconjugated monomers has provided the same level of control. Herein, an oxygen-tolerant photoenzymatic RAFT (reversible addition-fragmentation chain transfer) polymerization was exploited to tackle this challenge for unconjugated monomers at 10 °C, enabling facile synthesis of well-defined, linear and star polymers with near-quantitative conversions, unprecedented UHMWs and low dispersities. The exquisite level of control over composition, MW and architecture, coupled with operational ease, mild conditions and environmental friendliness, broadens the monomer scope to include unconjugated monomers, and to achieve previously inaccessible low-dispersity UHMWs. 相似文献
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Mineto Uchiyama Prof. Dr. Kotaro Satoh Prof. Dr. Masami Kamigaito 《Angewandte Chemie (International ed. in English)》2015,54(6):1924-1928
A metal‐free, cationic, reversible addition–fragmentation chain‐transfer (RAFT) polymerization was proposed and realized. A series of thiocarbonylthio compounds were used in the presence of a small amount of triflic acid for isobutyl vinyl ether to give polymers with controlled molecular weight of up to 1×105 and narrow molecular‐weight distributions (Mw/Mn<1.1). This “living” or controlled cationic polymerization is applicable to various electron‐rich monomers including vinyl ethers, p‐methoxystyrene, and even p‐hydroxystyrene that possesses an unprotected phenol group. A transformation from cationic to radical RAFT polymerization enables the synthesis of block copolymers between cationically and radically polymerizable monomers, such as vinyl ether and vinyl acetate or methyl acrylate. 相似文献
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Rui Xu Dr. W. Bernd Schweizer Dr. Holger Frauenrath Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(36):9105-9116
A series of symmetrically and unsymmetrically substituted octa‐2,4,6‐triyne‐1,8‐diol derivatives with benzoyl, 4‐dodecyloxybenzoyl, as well as perfluorobenzoyl substituents were prepared and investigated with respect to their crystal structures and topochemical polymerizability. Single‐crystal structures for several of these triacetylene monomers have been obtained and proved that the perfluorophenyl–phenyl interactions played a decisive role in the molecular packing. As a consequence of the geometric requirements imposed by the perfluorophenyl–phenyl interactions, packing parameters appropriate for a topochemical triacetylene polymerization in the sense of either a 1,6‐ or a 1,4‐polyaddition along different crystallographic axes were observed in two cases, and UV irradiation led to successful polymerization. Raman as well as solid‐state 13C NMR spectra of the obtained polymers revealed that the polymerization had predominantly proceeded in the form of a 1,4‐polyaddition. 相似文献