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1.
用三异丙氧基钕与顺丁烯二酸酐反应合成含钕单体二(顺丁烯二酸异丙酯酰氧基) 异丙氧基钕,并与甲基丙烯酸甲酯(MMA)共聚而制得含钕共聚物.用元素分析、IR、XPS和SEM对其结构进行表征,并研究了其热性能、光学性能和磁性.表明含钕共聚物是一种具有优异热稳定性、高透光率和大折光率,以及具有光选择吸收性和顺磁性的高分子材料  相似文献   

2.
用三异丙氧基钕与顺丁烯二酸酐反应合成含钕单体二-异丙氧基,并与甲基丙烯酸甲酯共聚而制得含共聚物。用元素分析、IR、XPS和SEM对其结构进行表征,并研究了其热性能、光学性能和磁性。  相似文献   

3.
研究了以N-异丙基马来酰亚胺(IPMI)与甲基丙烯酸甲酯共聚物为基材,制备渐变形耐温塑料光纤的可行性。实验确定了链转移剂和N-烷基马来酰亚胺对体系玻璃化温度的影响。通过Lorentz-Lorenz公式,估算出IPMI在共聚物中的折光率值。用元素分析法证明IPMI在塑料光纤预制棒中呈渐变分布,测定了以此材料制备的塑料光纤预制棒的折光率分别布线,说明IPMI在提高塑料光纤耐温性的同时,可作为参杂剂使用。结果表明:IPM/MMA共聚物是制备渐变型耐温塑料光纤的良好材料。  相似文献   

4.
用复分解的方法制备了辛酸钕[Nd(OCA)_3]和甲基丙烯酸钕[Nd(MAA)_3];将它们分别加入甲基丙烯酸甲酯和甲基丙烯酸的混合体系,聚合后得到交联的[含Nd(MAA)_3]和非交联的[含有Nd(OCA)_3]二种聚合物。研究了上述钕的有机酸盐和二种含钕聚合物的荧光性质。  相似文献   

5.
含噻吩的窄带隙共轭聚合物类太阳能电池材料因其良好的稳定性和可加工性,已成为新型太阳能电池的研究热点。本论文主要介绍了用于太阳能电池的窄带隙共轭聚合物研究进展,按其结构特征分为烷基/烷氧基取代聚噻吩、含苯基聚噻吩、基于噻吩并吡嗪的共聚物、基于噻吩并噻唑的共聚物、基于噻吩并吩噻嗪的共聚物、基于烷基芴的共聚物以及其它种类的窄带隙的共轭聚合物,并对它们的结构特点、光学带隙、合成方法进行了归纳与总结。本文最后简要介绍了该研究领域目前所面临的一些问题,同时讨论了该类材料在此领域今后的发展趋势。  相似文献   

6.
四配位硅单体及其共聚物的制备和结构表征   总被引:4,自引:0,他引:4  
研究了直接从无定形二氧化硅出发, 与乙二醇、氢氧化钾反应, 生成高反应活性的五配位硅钾化合物, 并以此为原料与含活泼氯的3-氯丙烯反应制备出含双键官能团的四配位硅单体. 讨论了合成单体的条件如温度、反应时间、反应物浓度、溶液pH值及溶剂等因素的影响. 然后以该四配位硅单体与甲基丙烯酸甲酯(MMA)在偶氮二异丁腈(AIBN)作引发剂下进行自由基聚合得到支链含硅共聚物. 并借助于红外光谱(IR)、核磁共振(13C和1H, 29Si)、能谱元素分析对合成的单体进行了结构表征; 用红外光谱(IR)、热失重谱(TG)、差示扫描量热谱(DSC)、凝胶渗透色谱法(GPC)等现代测试手段对支链含硅共聚物进行了结构表征及热性能分析. IR表明四配位硅单体在1646 cm-1处是C=C的伸缩振动吸收峰, 在共聚物中此峰消失; TG表明共聚物在249.6 ℃才开始失重, 552 ℃有机部分失重完毕; GPC分析表明共聚物的数均分子量为8.7万.  相似文献   

7.
用含氯前聚物路线和Heck反应分别合成[对苯乙炔-2,5-二(十二烷氧基)对苯乙炔]无规共聚物及交替共聚物.由元素分析、凝胶渗透色谱、吸收光谱及DSC对其进行表征,研究了共聚物的组成与导电率、溶解性及发光性能的关系.比较了无规共聚物与交替共聚物在性能上的差别.  相似文献   

8.
用含氯前聚物路线和Heck反应分别合成「对苯乙炔-2,5-二(十二烷氧基)对苯乙炔」无夫共聚物及交替共聚物,由元素分析,凝胶渗透色谱,吸收光谱及DSC对其进行了表征,研究了共聚物的组成与导电率,溶解性及发光性能的关系。  相似文献   

9.
甲基丙烯酸甲酯与N-苯基甲基丙烯酰胺本体共聚合的研究   总被引:4,自引:1,他引:4  
<正> 改进聚甲基丙烯酸甲酯(简称PMMA)耐热性能的方法,有采用将甲基丙烯酸甲酯(简称MMA)与多官能团的单体如甲基丙烯酸丙烯酯、甲基丙烯酸酐等共聚制得具有部分交联的共聚物;也有采用MMA与带有极性基团的单体如甲基丙烯酸、甲基丙烯酰胺(简称MAD)等共聚制得线型共聚物,以及其他方法。我们实验室曾报道了MMA  相似文献   

10.
红外光谱研究表明,苯乙烯-丙烯酸共聚物载体-钕络合物具有双配位的羧酸根结构,Nd-O键富有共价性。考察了载体钕络合物催化丁二烯聚合的一般规律,载体钕络合物的组成与聚合活性的关系。在溶剂THF或二氧六环的存在下制得的苯乙烯-丙烯酸共聚物最适宜于合成高活性的载体钕络合物。功能团-COOH含量大约12%,金属钕含量与功能团含量摩尔比在0.20左右的载体钕络合物催化活性最佳。  相似文献   

11.
In pursuit of nonbirefringent optical adhesives, various copolymers of methylmethacrylate and glycidylmethacrylate (MMA-co-GMA) were synthesized and subsequently blended with bisphenol-A diglycidyl ether (EPON-828) epoxy prepolymer using acetone as a common solvent. Miscibility and optical properties of these adhesive blends were investigated by means of differential scanning calorimetry (DSC), dielectric thermal analysis (DETA), and refractive index measurements. The increasing trend of the single glass transition temperatures of the copolymers as well as of their refractive indices with increasing MMA content suggests that these copolymers are probably of a random type. The adhesive blends, after curing with trimellitic anhydride (TMA), remained transparent, suggestive of a single-phase character. The complete miscibility of the adhesive blends made the refractive indices to be adjustable by simply varying the ratio of MMA-co-GMA copolymer in the blends. In addition, the positive and negative dielectric anisotropies (intrinsic birefringence) of the constituent molecules can be compensated fully in their cured states, thereby yielding significant reduction in the net birefringence in the blends of 50–80 wt % copolymer and a zero-birefringent optical adhesive at 60 wt %. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1911–1917, 1997  相似文献   

12.
The effect of flexible spacer length on the liquid crystalline property of ABA-type triblock copolymers containing azobenzene groups was investigated.For the study,the monomers,n-[4-(4-ethoxyphenylazo)phenoxy]alkyl methacrylates with varying methylene groups(n=0,2,6)were used to synthesize a series of azobenzene-containing amphiphilic triblock copolymers PAnC-PEG-PAnC by atom transfer radical polymerization(ATRP).Differential scanning calorimetry(DSC),polarizing optical microscopy(POM),and one-dimensional X-ray diffraction(1D WAXD)have shown that the glass transition temperatures of these copolymers decreased with increasing n,PAOC-PEG-PAOC has no mesophase,while both PA2C-PEG-PA2C and PA6C-PEG- PA6C have a nematic mesophase.These differences derive from the length of spacer groups between the polymer backbone and side-chain LC monomers.  相似文献   

13.
N-Methylacrylamide (NMAAm) was polymerized quantitatively by using di-tert-butyl peroxide as photosensitizer to be, for the most part, incorporated in living poly(NMAAm) radical. The living polymer radical reacted effectively with acrylate monomers to yield block copolymer. Longer alkyl chain of the acrylate monomer caused a decrease in the conversion of the second monomer. Methacrylate monomers, such as methyl methacrylate and cyclohexyl methacrylate, showed relatively low reactivities in comparison with acrylates. Styrene exhibited a much lower conversion. The resulting block copolymers showed different thermochromic behaviors in methyl benzoate from that of poly(NMAAm). This is explained on the basis of the difference between refractive indexes of the block copolymers and poly(NMAAm).  相似文献   

14.
We designed and synthesized novel UV‐curable multifunctional acrylate monomers with perfluorinated aromatic units and their copolymers. The UV‐curable multifunctional acrylate monomers with perfluorinated aromatic units were synthesized as follows. Perfluorinated aromatic methylmethane derivatives were prepared through the reaction of pentaerythritol with hexafluorobenzene and decafluorobiphenyl in the presence of sodium hydride. They were sequentially substituted with 2,2,3,3,4,4,5,5‐octafluoro‐6‐(tetrahydropyran‐2‐yloxy)‐hexan‐1‐ol, and this yielded hydroxy‐functional compounds after tetrahydropyran deprotection. Finally, the reaction of the resultant hydroxy compounds with acryloyl chloride generated the perfluorinated multifunctional acrylate monomers in high yields of greater than 85%. The novel photocrosslinked and perfluorinated copolyacrylates, obtained after the UV and thermal curing of these monomers, satisfied the material requirements for photonic devices. Most of these copolymers were thermally stable over 370 °C, and their glass‐transition temperatures were not detected because of their highly crosslinked nature. The refractive indices of the copolymers ranged from 1.410 to 1.441. The refractive indices of the photocrosslinked and perfluorinated copolyacrylates were easily tuned by the variation of the copolymer composition. Some of these copolymers exhibited a birefringence of less than 0.0003. This was much lower than the birefringence of fluorinated polyacrylate‐based materials. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6375–6383, 2004  相似文献   

15.
Graded‐index plastic optical fibers, composed of doped polymers, have advantages over conventional glass optical fibers, but need to be developed further for practical application. Here, a variety of aromatic sulfide dopants were synthesized, and their effects on the refractive indexes and glass transition temperatures (Tg) of poly(methyl methacrylate) and methyl 2‐chloroacrylate/2,2,2‐trichloroethyl methacrylate copolymers were studied. While polymers containing large dopants exhibited relatively high refractive indices, their Tg values were low, making these materials unsuitable for graded‐index plastic optical fiber applications. Six dopants yielded polymers that exhibited higher Tg values than the conventionally used (diphenyl sulfide)‐doped polymer. The dopant dibenzothiophene, in particular, yielded polymers with the highest refractive indexes and Tg values, and polymers containing (phenylthio)benzene dopants also performed well. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

16.
A series of liquid crystalline homopolysiloxanes and copolysiloxanes were synthesized. The chemical structures of the monomers M1-M7 were confirmed by FTIR and 1H NMR spectroscopy. The structure-property relationships of the monomers and polymers are discussed; their phase behaviour and optical properties were investigated by differential scanning calorimetry, thermogravimetric analysis, and polarizing optical microscopy. All the monomers, except M2 and M7 showed smectic and nematic phases; the copolymers P8-P15 displayed cholesteric phases. The homopolymers P1-P7 exhibited smectic phases. The selective reflection of cholesteric monomers and copolymers shifted to longer wavelengths with increasing length of the rigid mesogenic core, with decreasing length of the flexible spacer, or with increasing content of nematic units. Experimental results demonstrated that a flexible polymer backbone, a rigid mesogenic core and a long flexible spacer tended to produce a lower glass transition temperature, higher thermal stability, and wider mesophase temperature range.  相似文献   

17.
Evidence is given that, when solutions of diene monomers and anthracene in tetrahydrofuran are reacted with alkali metal and subsequently titrated with linking agents such as alkyl dihalides, copolymers are formed; they contain the 9,10-dihydroanthracene adduct and the diene in the same proportion as in the original solution. The structures of these copolymers have been elucidated by NMR spectroscopy and the mechanism of formation is discussed.  相似文献   

18.
Langevin dynamics simulations are performed on linear-dendritic diblock copolymers containing bead-spring, freely jointed chains composed of hydrophobic linear monomers and hydrophilic dendritic monomers. The critical micelle concentration (CMC), micelle size distribution, and shape are examined as a function of dendron generation and architecture. For diblock copolymers with a linear block of fixed length, it is found that the CMC increases with increasing dendron generation. This trend qualitatively agrees with experiments on linear-dendritic diblock and triblock copolymers with hydrophilic dendritic blocks and hydrophobic linear blocks. The flexibility of the dendritic block is altered by varying the number of spacer monomers between branch points in the dendron. When comparing linear-dendritic diblock copolymers with similar molecular weights, it is shown that increasing the number of spacer monomers in the dendron lowers the CMC due to an increase in flexibility of the dendritic block. Analysis on the micellar structure shows that linear-dendritic diblock copolymers pack more densely than what would be expected for a linear-linear diblock copolymer of the same molecular weight.  相似文献   

19.
设计并合成了5个系列的带有不同侧基的手性-非手性N-炔丙基酰胺共聚物,以铑有机配合物为催化剂对单体实施聚合反应得到高产率(>95%)的共聚物,聚合物具有高立构规整性(cis-含量高于94%).利用圆二色(CD)及紫外-可见吸收(UV-Vis)光谱技术对共聚物的二级结构及光学活性进行了表征,当非手性单体的酰胺侧基体积适中时,共聚物具有较高的光学活性,部分共聚物的光学活性甚至高于纯手性聚合物.表明通过选择合适的手性-非手性共聚单体及单体配比,可获得具有高光学活性的螺旋聚合物.  相似文献   

20.
Phenyl-rich silicone polymers are used for their excellent thermal properties and high refractive indices. Traditional syntheses of these polymers utilize cationic or anionic equilibration, which limits the molecular weights that can be achieved due, in part, to the coproduction of cyclic monomers that must be removed. Kinetically controlled processes may reduce the impact of these limitations, but require high temperatures, alkyllithium initiators and an inert atmosphere; precise structures are difficult to access. The Piers-Rubinsztajn reaction, combined with hydrolysis, allows the synthesis of highly ordered, Si-H terminated, phenyl-rich silicone homo- and copolymers comprised of phenylmethyl, diphenyl and, dimethylsilicone monomers. The processes are mild and permit a high level of structural control, including alternating copolymers with different levels of phenyl content (Ph/Si = 0.3–1.5) with molecular weights up to ~100 kDa. Yet higher molecular weights could be achieved—Mn up to 300 kDa—when phenyl-rich siloxanes were incorporated into block copolymers with dimethylsilicones (Ph/Si = 0.4). Unlike kinetic processes in which cyclic byproducts are formed by redistribution or backbiting (particularly at high conversion), in this process cyclics form near the onset of the reaction and only with low molecular weight starting materials (< 4 siloxane units).  相似文献   

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