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1.
合成接枝和嵌段共聚物是研究阻尼材料的重要途径。可以在较广的范围内,调整共聚物的结构,使之具有良好的阻尼性能。我们选择聚环氧丙烷与顺丁烯二酸酐反应,制成端乙烯基大分子单体和遥爪低聚物,与苯乙烯共聚,制成接枝和交联嵌段共聚物。探讨了不同结构因素对阻尼性能的影响规律,研究结果有益于阻尼材料的分子设计。  相似文献   

2.
本文在前报所合成的端羧基乙烯基四氢呋喃-环氧丙烷液体共聚醚的基础上,利用其端羧基同双官能团环氧反应,生成端环氧基三嵌段共聚物。然后再利用端乙烯基与烯类单体反应,制备了遥爪型三组份四臂星形共聚物。通过动态力学性能的测试,观察了一些因素对阻尼性能的影响。  相似文献   

3.
聚氨酯弹性体的相区相容性和阻尼性能研究   总被引:14,自引:0,他引:14  
合成了一系列含有不同软段的聚氨酯嵌段共聚物及接枝共聚物,并测试了其动态力学性能,结果表明,聚氨酯共聚物的相容性与大分子的链结构有关,接枝链的存在对聚氨酯嵌优共聚物相空性和阻尼性能有很大影响。  相似文献   

4.
本文研究了链段结构对多嵌段共聚物网的相容性及动态力学阻尼性能的影响。分别以端乙烯基低聚物作为软链段,乙烯类聚合物作为硬链段,制备了一系列具有不同链段结构共聚物网。它们在大于50℃的温度范围,能阻尼机械振动。共聚物网中某些软链段和硬链段成分是半相容的。基于这些配方的许多共聚物网,在需要的温度范围,tanδ>1.75。  相似文献   

5.
通过可控/活性正离子开环聚合设计合成一系列不同分子量的聚四氢呋喃活性链,利用聚二甲基硅氧烷(PDMS)的双端胺基与反应制备PDMS与聚四氢呋喃(PTHF)的新型三嵌段共聚物(PTHF-b-PDMS-b-PTHF).通过FTIR与1H-NMR表征产物化学结构及共聚组成,由TGA、DSC及DMA研究嵌段共聚物热性能与动态力学性能,采用TEM和in situ POM观察嵌段共聚物的微观形态与结晶形态.常温下表征共聚物材料自修复性能及37°C下表征其抗菌性能.结果表明:采用体系引发四氢呋喃可控/活性正离子开环聚合制备预期分子量的,进一步与双端胺基官能化PDMS反应,反应效率可达95%左右,设计合成出一系列不同共聚组成的PTHF-b-PDMS-b-PTHF三嵌段共聚物.该共聚物呈现双连续微观相分离结构和结晶现象,随着PTHF链段的增长,结晶速率加快;与相同分子量均聚PDMS和PTHF相比,所制备的三嵌段共聚物的热稳定性明显提高;三嵌段共聚物链中存在2个―NH―基团,在分子链间形成氢键导致产生物理交联及聚合物网络,使材料具有较好的弹性、柔韧性和强度,同时具有自修复特性,将材料完全切开,常温下24 h后断面发生良好愈合,在应力作用下可被拉伸至原长的1.5倍;原位制备的三嵌段共聚物/银纳米复合材料对大肠杆菌表现出良好的抗菌性能.基于可控/活性正离子开环聚合方法合成的PTHF-b-PDMS-b-PTHF三嵌段共聚物/银纳米复合材料兼具PTHF、PDMS及纳米银的优良性能,在生物医用材料领域具有应用前景.  相似文献   

6.
研究了从端乙酰氧基聚醚代替端羟基聚醚合成聚对苯二甲酸乙二酯-聚四亚甲基醚多嵌段共聚物的新途径。探讨了其嵌段共聚合反应过程。所合成的嵌段共聚物是性能优良的热塑弹性体。  相似文献   

7.
合成了α-苯基乙基钾,并用于制备AB型聚苯乙烯(A)-聚氧乙烯(B)嵌段共聚物。研究了聚合时间和温度的影响。通过含一个端羟基的AB嵌段共聚物与偶联剂甲苯二异氰酸酯反应制得ABA型嵌段共聚物。二种共聚物均经纯化,并用NMR、IR、UV、DSC、偏光显微镜及X-射线衍射法表征,且与均聚物的混合物比较。  相似文献   

8.
张勇杰  李化毅  曲敏杰  冯钠  杨威  张翀 《化学进展》2016,28(11):1634-1647
实现聚烯烃功能化是制备高性能聚烯烃材料、拓展聚烯烃应用的重要手段,几十年来得到了学术界及工业界的广泛关注。聚烯烃接枝共聚物作为一类重要的功能化聚烯烃,包含聚烯烃链段(PE、PP等)及功能化聚合物链段(PS、PMMA、PEG等),因而在提高功能单元含量的同时能保持聚烯烃单元优异的结晶、加工性能。结构明确的聚烯烃接枝共聚物,具有结构参数可控、综合性能可调的特点,对于认识聚合物材料结构-性能关系、拓展聚烯烃应用范围具有重要的学术和实际意义。聚烯烃接枝共聚物的合成方法可以分为三种类型:“共聚接枝(graft-through)”、“引出接枝(graft-from)”、“偶联接枝(graft-onto)”。前两种合成方法往往涉及烯烃配位聚合与其他聚合方式的机理转化过程;其中,反应性聚合物中间体作为大分子引发剂、大分子RAFT试剂、大分子单体参与接枝反应,实现接枝共聚物的可控制备。第三种方法思路简单明确,即利用聚烯烃侧基反应性基团与其他聚合物反应性端基之间的高效偶联反应实现接枝共聚物制备。本文从合成、结构及性能三方面较为全面地综述了结构明确聚烯烃接枝共聚物的研究进展,着重讨论了新兴合成方法及相应接枝共聚物的潜在应用。  相似文献   

9.
用端基反应法合成了对乙烯基苄基的聚乙二醇大分子单体,将该大分子单体与甲基丙烯酸六氟丁酯共聚,合成了一种含氟两亲接枝共聚物.利用1H-NMR1、9F-NMR、GPC对大分子单体和两亲接枝共聚物进行了表征.表面张力法测定了两亲接枝共聚物的临界胶束浓度,发现随着共聚物中含氟链段含量的增加,其临界胶束浓度降低.采用荧光光谱研究了含氟两亲接枝共聚物与牛血清蛋白(BSA)的相互作用,结果表明由于含氟链段疏水力的作用,含氟两亲接枝共聚物能与牛血清蛋白发生相互作用使其荧光增强,随着含氟两亲接枝共聚物浓度和共聚物中含氟链段含量的增加,荧光增强幅度加大.通过透射电子显微镜(TEM)和激光光散射粒度仪(PCS)测试发现,当BSA加入到含氟两亲接枝共聚物的胶束溶液后,所得胶束的粒径和粒径分布变大,共聚物胶束由规整的实心核壳结构变为囊泡状核壳结构.  相似文献   

10.
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).  相似文献   

11.
Carboxyl vinyl terminated polytetrahydrofuran macromers and telechelic oligomers were synthesized from hydroxyl terminated polytetrahydrofuran by end group conversion. From these macromers or telechelic oligomers and styrene polytetrahydrofuran/polystyrene segmented and graft copolymers were synthesized and the effects of molecular structure on the damping properties of those copolymers were also studied.  相似文献   

12.
ABA‐type copolymers were synthesized by the anionic polymerization of hexanelactam with the sodium salt of hexanelactam as an initiator and amino‐terminated polytetrahydrofuran telechelic functionalized with diisocyanates. Two types of diisocyanates, hexamethylene diisocyanate (1,6‐diisocyanatohexane) and isophorone diisocyanate (IF; 5‐isocyanato‐1‐isocyanatomethyl‐1,3,3‐trimethylcyclohexane), were used as precursors for polymeric activators (PACs). IF was used for the first time. It was proven that the PACs were incorporated as soft, flexible midblocks in the chains of hard nylon‐6 segments. The polymers were isolated and characterized with various spectroscopic techniques. The effects of the central PAC block (according to the type, molecular weight, and content) and the polymerization conditions on the kinetics, activation energies, molecular weights, and structures of the triblock copolymers were investigated. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4154–4164, 2000  相似文献   

13.
The transfer of hydrogen from a free radical to an olefin is catalyzed by some cobalt chelates. This reaction, when used in free-radical polymerization, can be called catalytic chain transfer (CCT) to a monomer. It allows the manufacture of oligomers that have defined molecular weights and are useful for a variety of applications. Because all the oligomers are getting terminal double bonds, they can behave as macromers. These macromers give rise to the formation of diblock and graft copolymers, telechelic polymers that have the same or different functional groups depending on the conditions and origins of the comonomers. The catalyst structure–property relation is discussed. Redox properties affect the CCT and provide additional leverage in controlling polymerization processes. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1753–1766, 2000  相似文献   

14.
聚环氧乙烷为支链的两亲共聚物的表征及性能   总被引:5,自引:0,他引:5  
用端基带有甲基丙烯酸酯的聚环氧乙烷大分子单体(PEO—MA)分别与小分子单体苯乙烯(S)、甲基丙烯酸甲酯(MMA)、丙烯酸甲酯(MA)溶液自由基共聚合得到了三种具有不同主链结构的以聚环氧乙烷(PEO)为支链的两亲接枝嵌段共聚物(分别简写为:PS─g─PEO,PMMA─g─PEO,PMA─g─PEO).用GPC、IR、1H─NMR、WAXD和DSC对其结构进行了表征.研究了接校共聚物的结晶性能、乳化性能以及在Williamson反应中相转移催化作用.结果表明,不同主链结构有不同的结晶度,并随支链PEO含量的增加,分子量的增大而提高;其乳化体积和相转移催化反应的转化率均随着共聚物浓度的增加、支链PEO含量的增人而增大,随支链PEO分子量的提高而减小.  相似文献   

15.
Nanophase‐separated, hydrophilic–hydrophobic multiblock copolymers are promising proton‐exchange‐membrane materials because of their ability to form various morphological structures that enhance transport. A series of poly(2,5‐benzophenone)‐activated, telechelic aryl fluoride oligomers with different block molecular weights were successfully synthesized by the Ni(0)‐catalyzed coupling of 2,5‐dichlorobenzophenone and the end‐capping agent 4‐chloro‐4′‐fluorobenzophenone. These telechelic oligomers (hydrophobic) were then copolymerized with phenoxide‐terminated, disulfonated poly(arylene ether sulfone)s (hydrophilic) by nucleophilic, aromatic substitution to form hydrophilic–hydrophobic multiblock copolymers. High‐molecular‐weight multiblock copolymers with number‐average block lengths ranging from 3000 to 10,000 g/mol were successfully synthesized. Two separate glass‐transition temperatures were observed via differential scanning calorimetry in the transparent multiblock copolymer films when each block length was longer than 6000 g/mol. Tapping‐mode atomic force microscopy also showed clear nanophase separation between the hydrophilic and hydrophobic domains and the influence of the block length as it increased from 6000 to 10,000 g/mol. Transparent and creasable films were solvent‐cast and exhibited moderate proton conductivity and low water uptake. These copolymers are promising candidates for high‐temperature proton‐exchange membranes in fuel cells, which will be reported separately in part II of this series. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 284–294, 2007  相似文献   

16.
一锅法合成甲基丙烯酰基封端的PLA-PEG-PLA大分子单体   总被引:2,自引:0,他引:2  
以辛酸亚锡[Sn(Oct)2]为催化剂、聚乙二醇为引发剂引发丙交酯开环聚合,用水终止反应后再加入甲基丙烯酸酐反应即可得到甲基丙烯酰基封端的PLA-PEG-PLA大分子单体。上述两步反应可一锅进行,操作简便、收率高。采用GPC、FTIR、^1H-NMR、TG、XRD等分析手段表征了大分子单体的结构和性质。所得大分子单体的水溶液在光引发剂存在下,能被UV引发光聚合形成水凝胶。该水凝胶作为可降解生物材料可用于药物控释栽体和组织工程支架。  相似文献   

17.
Methods were elaborated for the synthesis of new monomers, derivatives of diallylguanidine and macromers, which contain fragments of polytetrahydrofuran and diallylic nitrogencontaining end groups (diallylamine, alkyldiallylammonium, diallylguanidine both in base and acetate forms). Alkylation of a macromer with a diallylamine end group was carried out with methyl iodide in various organic solvents. The possibility of synthesis of diallylguanidine acetate homopolymer as well as its statistical copolymer with diallyldimethylammonium chloride was shown. For the first time, block copolymers based on synthesized macromers were obtained.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1976–1982, November, 1994.The work was supported in part by the Russian Foundation For Basic Research (project code 94-03-08924a).  相似文献   

18.
New ω‐methacryloxy‐terminated N‐vinyl‐2‐pyrrolidinone oligomers were prepared by reaction of the corresponding ω‐hydroxy‐terminated N‐vinyl‐2‐pyrrolidinone oligomers with 2‐[(1‐imidazolyl)formyloxy] ethyl methacrylate (HEMA‐Im). The oligomeric precursor had been obtained by radical chain transfer polymerization making use of isopropoxyethanol as a solvent and a chain transfer agent. α,ω‐Dimethacryloxy‐terminated ε‐caprolactone and δ‐valerolactone oligomers were also prepared by reaction of their α‐hydroxy‐ω‐methacryloxy‐terminated precursors with HEMA‐Im. These had been in turn synthesized by ring‐opening polymerization of the corresponding lactones in the presence of 2‐hydroxyethyl methacrylate as the initiator and tin octanoate as the catalyst. Due to the presence of methacrylic functions at their chain ends, both VP and lactone oligomers participate in radical polymerization reactions and can be therefore classified as radical macromers. Both macromer families have several potential applications, such as use in the synthesis of mixed hydrophilic/hydrophobic hydrogels. All macromers were characterized by NMR spectroscopy and size‐exclusion chromatography (SEC). The polymerization kinetics of the lactone macromers were also analyzed by 1H NMR spectroscopy.  相似文献   

19.
以辛酸亚锡为催化剂 ,通过星型聚乙二醇 (PEG)引发ε 己内酯 (CL)开环聚合 ,制备了PEG b PCL嵌段共聚物 ,进一步以丙烯酸酯封端 ,合成了 3种水溶性大分子单体 .以 2 ,2 二甲氧基 2 苯基苯乙酮为引发剂 ,在紫外光作用下 ,大分子单体在水中由于胶束的形成能够迅速聚合形成水凝胶 .利用1 H NMR、FTIR、DSC、TGA、ESEM、凝胶含量、溶胀比等分析测试手段对大分子单体及其形成的水凝胶进行了表征 .结果表明 ,干胶迅速吸水而达到溶胀平衡 ,水凝胶具有较大的溶胀比和高的水含量 ;随着PEG臂数的增加 ,干胶的熔融峰顶温度下降 ,凝胶的溶胀比减小 ;ESEM图片上清晰地表明水凝胶的网络结构  相似文献   

20.
Polyetheretherketone-polydimethylsiloxane (PEEK–PDMS) block copolymers were synthesized from the condensation of dimethylamino terminated PDMS and hydroxy terminated PEEK oligomers in 1-chloronapthalene. Yields for block copolymers synthesised from low molecular weight PDMS oligomers were good but yields were significantly reduced when higher molecular weight PDMS oligomers were used. This was related to the limited solubility of higher molecular weight PDMS in the reaction solvent. Differential scanning calorimetry (DSC) studies indicated that phase separation of the block copolymers occurred at very short segment length (M?n < 4000). A depression in the crystallinity of both the PEEK and PDMS phases in the block copolymer was observed. Thermogravimetric analysis (TGA) studies indicated that the PEEK–PDMS block copolymers displayed insufficient thermo-oxidative stability to be melt-processed successfully in PEEK based blends.  相似文献   

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