共查询到20条相似文献,搜索用时 15 毫秒
1.
从4-羟基偶氮苯出发,依次与2-氯乙醇、丙烯酰氯反应,合成了2-(4-苯基偶氮苯氧基)乙基丙烯酸酯(PAPEA)。接着以PAPEA为单体,二硫代苯甲酸异丁腈酯(CPDB)为链转移剂,偶氮二异丁腈(AIBN)为引发剂,利用可逆加成-断裂链转移(RAFT)聚合法合成了聚[2-(4-苯基偶氮苯氧基)乙基丙烯酸酯](PPAPEA)均聚物,同时考察了反应时间、引发剂和链转移剂浓度等因素对聚合反应的影响。利用FT-IR、1H-NMR和GPC等对单体和聚合物的结构进行了表征,并利用UV对聚合物的光响应性能进行了测试。结果表明,PAPEA的聚合反应动力学曲线呈良好的线性关系,分子量分布较窄(小于1.3);均聚物在紫外光照下的异构化速率随分子量的增大而减缓,而其在自然光下的回复速率变化不大。 相似文献
2.
Superhydrophobic surfaces were obtained by coating with microspheres formed by the self-assembly of poly[2-(perfluorooctyl)ethyl
acrylate-ran-2-(dimethylamino)ethyl acrylate] (P[POA-r-DAA]) in the presence of dicarboxylic acids in supercritical carbon dioxide. The P[POA-r-DAA] random copolymer aggregated into micellar microspheres through the hydrogen bond cross-linking of the amino groups via
the carboxylic acids. The size of the microspheres and the amount of the acids needed to produce them were dependent on the
kinds of acids. Glutaric acid (Glu) and perfluorosuccinic acid (Psuc) provided microspheres at a 0.5 molar ratio of the acid/DAA.
Psuc produced smaller microspheres than Glu. Maleic acid (Ma), succinic acid (Suc), and azelaic acid (Az) required a higher
molar ratio to produce the microspheres. These acids provided spherical particles at the ratio of 1.0. The microspheres produced
by Suc and Az contained particles with a several hundred nanometer size. The surface coated with the microspheres showed high
water contact angles of 164°–172°.
相似文献
Eri YoshidaEmail: |
3.
The thermal degradation behaviour of poly(ethyl methacrylate) homopolymers and poly(ethyl methacrylate) and poly(ethyl acrylate) copolymers synthesized by using the benzoyl peroxide-di-methyl aniline redox pair at different temperatures (18–35C) was investigated. Contrary to some reports in the literature, the thermal degradation of PEMA was observed to take place in multi steps. These are assigned to be loss of labile end groups, side chain scission, anhydride formation and main chain degradation steps. Dominating chemical formations at the end of these steps were characterized by FTIR spectroscopy.The homopolymer samples synthesized at 18C showed a greater thermal stability against degradation. Copolymerization with small amounts of ethyl acrylate was observed to impart thermal stability to PEMA by stabilizing mainly the end groups against degradations. 相似文献
4.
Juan R. Gonzlez-Velasco Jos A. Delgado Jos A. Gonzlez-Marcos Miguel A. Gutirrez-Ortiz 《Journal of polymer science. Part A, Polymer chemistry》1999,37(23):4309-4317
The kinetic model of thermooxidative degradation in air, proposed to be valid for poly(2-hexyne) in predicting the lifetime of substituted polyacetylenes, was applied to poly[1-(trimethylsilyl)-1-propyne] films, with the differences in the oxidative behavior of both polyacetylenes noted. The effect of the molecular weight of the sample on the degradation process was analyzed. Kinetics of weight loss and chain scission were modeled, and the kinetic parameters were calculated. Also, the evolution of weight loss was related to the chain scission. The proposed model was validated with data reported in the literature. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4309–4317, 1999 相似文献
5.
5-氟尿嘧啶-聚[N-(2-羟乙基)-L-谷酰胺]的合成及缓释性能研究 总被引:6,自引:0,他引:6
以聚谷氨酸苄酯为原料,用乙醇胺进行胺解得水溶性的可生物降解的聚[N-(2-羟乙基)-L-谷酰胺];用光气/甲苯液活化5-氟尿嘧啶,将其以共价键形式键合在高分子上,得5-氟尿嘧啶的高分子前药。用IR、UV、1HNMR及DSC对其结构进行表征,用紫外光谱测定其药物含量,载药高分子的接药率约为38.4%,高分子前药在pH=7.2的磷酸盐介质中42天内的药物累积释放量为57.53%。实验结果表明,5-氟尿嘧啶以共价键的形式键合在聚[N-(2-羟乙基)-L-谷酰胺]之上,在体外有明显的缓释效果。 相似文献
6.
Raul O. Garay Bernd Mayer Frank E. Karasz Robert W. Lenz 《Journal of polymer science. Part A, Polymer chemistry》1995,33(3):525-531
The synthesis of a highly soluble, 2,5-disubstituted poly(p-phenylene vinylene) with pendant side chains containing ether groups was accomplished by a dehydrochlorination route. Specific interactions of the oxygen-containing side chains with the solvent are presumably responsible for the high solubility of the polymer, especially in protogenic solvents. The polymer microstructure was characterized by 1H- and 13C-NMR. The polymer showed solvatochromic properties when dissolved in a variety of solvents. The relatively high molecular weight (Mn = 17,000) permitted the fabrication of free-standing films. The electrical conductivity of iodine-doped films was approximately 2 × 10–2 S cm–1. © 1995 John Wiley & Sons, Inc. 相似文献
7.
The plasticization by 4-decylaniline (4DA) of a microphase-separated poly(ethyl acrylate) ionomer containing sodium carboxylate groups is examined. Dynamic mechanical thermal analysis, supplemented by differential scanning calorimetry, shows that the matrix and cluster glass transitions (Tg's) in the ionomer are both depressed by ca. 1°C/wt % 4DA; this, in turn, is similar to the Tg depression in the blend of the parent poly(ethyl acrylate) (PEA) with 4DA. There is no evidence of 4DA crystallinity in the blend. Small-angle x-ray scattering (SAXS) measurements show that the ionomer peak increases in intensity and decreases in scattering angle with increasing concentration of 4DA in the blend; the corresponding Bragg spacing, initially at 2.3 nm, increases by ca. 0.04 nm/wt % 4DA. These results, supported by preliminary spectroscopic measurements, are attributed to hydrogen bonding interactions between the amine groups of 4DA and the ester groups in PEA and the ionomer, rendering the blend miscible. It is argued that the uniform distribution of 4DA throughout the material plasticizes both phases of the ionomer by adding free volume; this also accounts for the increase in the characteristic spacing detected by SAXS. 相似文献
8.
依据邻羟基二苯醚及芳香肼类化合物的抗菌特性, 以邻羟苯基为分子核心, 酰肼键为桥基, 设计合成了7种未见报道的N-(取代苯基)乙基-2-羟基苯甲酰肼类化合物. 以水杨酸甲酯为原料, 经肼解反应后与取代苯乙酮缩合, 再与硼氢化钠反应制得目标化合物, 化合物结构经IR, 1H NMR和元素分析等证实. 抗菌活性测试结果表明, 该类化合物对不同菌株的抑菌活性具有明显的选择性和特异性. 当质量浓度为1×10-4 g/mL时, 化合物3b和3e对大肠杆菌和白色念珠菌的抑菌率高达100%, 有极强的抑菌活性; 所有化合物对金黄色葡萄球菌的抑菌率均大于70%, 有一定的抑菌活性. 构效关系分析结果表明, 苯基中引入Cl或Br等卤原子能显著增强化合物的抑菌活性, 而引入-NO2及-CH3基团则会降低其抑菌活性. 相似文献
9.
Kazuo Sugiyama Kohei Shiraishi Takako Matsumoto 《Journal of polymer science. Part A, Polymer chemistry》2003,41(13):1992-2000
Poly[2‐(methacryloyloxy)ethyl phosphorylcholine]s (PMPCs) with one pendant cholesteryl moiety at the polymer end (PMPC‐Chol‐I and PMPC‐Chol‐II) and two pendant cholesteryl moieties at both polymer ends as terminal groups (PMPC‐2Chol‐I and PMPC‐2Chol‐II) were prepared by the radical polymerization of 2‐(methacryloyloxy)ethyl phosphorylcholine initiated with 4,4′‐azobis[(3‐cholesteryl)‐4‐cyanopentanoate] in the presence of 2‐mercaptoethanol or thiocholesterol as chain‐transfer reagents, respectively. The self‐organization of PMPC‐Chol and PMPC‐2Chol was analyzed with fluorescence and 1H NMR measurements. The critical micelle concentrations of PMPC‐Chol‐I with a degree of polymerization (Pn) of 91 and of PMPC‐2Chol‐I with a Pn value of 165 were 250 and 27 mg L?1, respectively. The blood compatibility of PMPC‐2Chol was evaluated from the Michaelis constant (Km) for the enzymatic reaction of thrombin and a synthetic substrate, S‐2238, in the presence of PMPC‐2Chol. Km was 0.07, 0.05, and 0.56 for PMPC‐2Chol‐I with Pn = 165, PMPC‐2Chol‐II with Pn = 38, and PMPC (an intrinsic viscosity of 0.54 dL g?1) initiated with 2,2′‐azobisisobutyronnitrile in the absence of chain transfer agent, respectively. A mixture of PMPC‐2Chol‐II and cholesterol as a drug model formed a lamellar type of complex with an interplanar spacing of d = 35.2 Å. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1992–2000, 2003 相似文献
10.
11.
Nina K. Gusarova Nina I. Ivanova Maria V. Bogdanova Lidiya M. Sinegovskaya Alexander V. Gusarov Boris A. Trofimov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1749-1754
Abstract Phosphine, generated from elemental phosphorus in the system KOH-toluene-H2O, reacts with vinyl sulfides under free radical conditions (AIBN, dioxane, 65–70°C, atmospheric pressure) to form regiospecifically tris[2-(organylthio)ethyl]phosphines, which are readily oxidized in air to corresponding tris[2-(organylthio)ethyl]phosphine oxides. 相似文献
12.
Agapi Zioga Nikos Ekizoglou E. Siakali-Kioulafa Nikos Hadjichristidis 《Journal of Polymer Science.Polymer Physics》1997,35(10):1589-1592
The synthesis, characteristic ratio C∞ and glass transition temperature (Tg) of poly(tetrahydrofurfuryl acrylate) (PTHFA) and of poly(2-ethylbutyl acrylate) (P2EBA) are reported. P2EBA has slightly lower flexibility (C∞ = 9.2) than PTHFA (C∞ = 8.6), mainly because of the higher bulkiness of its side group and the closer proximity to the main chain. The C∞ results compared with the corresponding polymethacrylates show an increase in flexibility due to the absence of the α-methyl group. Comparison with poly(methyl acrylate) clearly shows the influence of the bulkiness of the side group on the chain flexibility. The lower Tg of P2EBA than that of PTHFA may be explained by the higher flexibility of the 2-ethylbutyl side group. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 1589–1592, 1997 相似文献
13.
L. C. Witchey-Lakshmanan H. B. Hopfenberg R. T. Chern 《Journal of Polymer Science.Polymer Physics》1993,31(11):1545-1553
The linear expansion and contraction in the principal planar directions of poly[1-(trimethylsilyl)-1-propyne] film were measured concurrently with the sorption of n-nonane at 35°C. After the first sorption cycle, in which the polymer exhibited markedly nonisotropic volumetric dilation, the polymer expanded and contracted reproducibly during subsequent multiple sorption and desorption cycles. These reversible dilation isotherms were reproducible from sample to sample. The fractional change in length was identical in arbitrarily selected, orthogonal directions in the plane of the film, suggesting that the expansion and dilation of the sample are isotropic. When plotted versus the activity of n-nonane, the linear expansions in the plane of the film are slightly concave to the activity axis, reaching levels over 10% at the highest activities. The experimental partial specific volume of the polymer is near its pure component value but that of the penetrant is much less than its pure component value. Moreover, the magnitude of dilation observed is described rather closely by the dilation which would result solely from the Henry's law portion of sorption, assuming zero volume-change of mixing. These results are consistent with the explicit notions of “hole-filling” associated with the Langmuir mode in the dual-mode model. © 1993 John Wiley & Sons, Inc. 相似文献
14.
Novel synthetic transfection vectors with linear triblock and star-shaped diblock copolymer architectures have been synthesized by atom transfer radical polymerization (ATRP). Based on 2-(dimethylamino)ethyl methacrylate (DMAEMA) and copolymerization with poly(ethyleneglycol) α-methoxy, ω-methacrylate (MAPEG), the synthesis was realized using CuBr ligated with 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) as catalytic complex and either ethyl 2-bromoisobutyrate (EBiB) or bis(α-bromoisobutyryl) N-methyl diethanolamine (DEA) or tris(α-bromoisobutyryl) triethanolamine (TEA) as (multifunctional)initiator. The polymers were characterized by GPC and NMR. The solution properties of these homopolymers and palm-tree-like copolymers were investigated by viscometry either in pure water or in buffered aqueous solutions. Interestingly, all the synthesized polymers show polyelectrolyte effect in Millipore water (25 °C) and in Hepes (20 mM) buffer solution (pH 7.4, NaCl 155 mM, 25 °C). Fitting of these viscometric data according to either Fuoss or Fedors equation allows for calculating the intrinsic viscosity of the polymers. These results are compared with dynamic light scattering (DLS) experiments to determine absolute masses. Finally, DEA based palm-tree-like copolymer is investigated to AFM measurement and micelles were observed at pH 8. 相似文献
15.
16.
对-二甲氨基苯甲醛和苯基氨基硫脲缩合反应生成1-[4-(二甲氨基)苯亚甲基氨基]-4-苯基硫脲(DMB), 产物能从溶液中析出单一手性对映体晶体. 用单晶X射线衍射技术测定了它的绝对构型, 晶体属正交晶系, P212121空间群, a=0.7870(2) nm, b=1.1560(2) nm, c=1.6668(3) nm, V=1.5164(5) nm3, Z=4, Dc=1.307 g/cm3, F(000)=632, μ=0.213 mm-1, 2557个可观测点[I>2s(I)]精修的最终残差因子: R=0.0409, wR=0.1061, Flack参数为0.00(9), 能够确定绝对构型. 化合物的晶体结构和大宗粉末样品的固体圆二色谱表明化合物在结晶过程中发生单一对映体的手性堆积. 相似文献
17.
Ivonne L. Diaz Cesar A. Sierra Valérie Jérôme Ruth Freitag León D. Perez 《Journal of polymer science. Part A, Polymer chemistry》2020,58(16):2168-2180
A series of copolymers composed of methoxy poly(ethylene glycol) and a hydrophobic block of poly(ɛ-caprolactone-co-propargyl carbonate) grafted with poly(2-[dimethylamino]ethyl methacrylate) was synthesized by combining ring opening polymerization, azide-alkyne click reaction, and atom transfer radical polymerization (ATRP). Well-defined copolymers with a target composition and a tailored structure were achieved via the grafting from approach by using a single catalytic system for both click reaction and ATRP. Kinetic studies demonstrated the controlled/living character of the employed polymerization methods. The thermal properties and self-assembly in aqueous medium of the graft copolymers were dependent on their composition. The resulting polymeric materials showed low cytotoxicity toward L929 cells, demonstrating their potential for biomedical applications. This type of materials containing cationic side chains tethered to biocompatible and biodegradable segments could be the basis for promising candidates as drug and gene delivery systems. 相似文献
18.
A combined optical and electron microscopical study has been carried out of the crystallization habits of poly(vinylidene fluoride) (PVF2) when it is crystallized from blends with noncrystallizable poly(ethyl acrylate) (PEA). The PVF2/PEA weight ratios were 0.5/99.5,5/95, and 15/85. Isothermal crystallization upon cooling the blends from the single-phase liquid region was carried out in the range 135–155°C, in which the polymer crystallizes in the α-orthorhombic unit cell form. The 0.5/99.5 blend yielded multilayered and planar lamellar crystals. The lamellae formed at low undercoolings were lozenge shaped and bounded laterally by {110} faces. This habit is prototypical of the dendritic lateral habits exhibited by the crystals grown from the same blend at high undercoolings as well as by the constituent lamellae in the incipient spherulitic aggregates and banded spherulites that formed from the 5/95 and the 15/85 blends, respectively. In contrast with the planar crystals grown from the 0.5/99.5 blend, the formation of the aggregates grown from the 5/95 blend is governed by a conformationally complex motif of dendritic lamellar growth and proliferation. The development of these aggregates is characterized by the twisting of the orientation of lamellae about their preferential b-axis direction of growth, coupled with a fan-like splaying or spreading of lamellae about that axis. The radial growth in the banded spherulites formed from the 15/85 blend is governed by a radially periodic repetition of a similar lamellar twisting/fan-like spreading growth motif whose recurrence corresponds to the extinction band spacing. This motif differs in its fan-like splaying component from banding due to just a helicoidal twisting of lamellae about the radial direction. © 1993 John Wiley & Sons, Inc. 相似文献
19.
We have used semiempirical calculations (PM3, MNDOd) to show that the parabolic dependence of the rate constants (kobs, s−1) on the picryl iodide (PicI) concentration in the reaction of quaternization of 4-[4-(dimethylamino)styryl]pyridine (DASP)
in acetonitrile is due to formation of an inactive σ1,3 adduct from DASP and PicI. Formation of the σ1,1 adduct is the rate-limiting step of the SNAr substitution.
__________
Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 41, No. 4, pp. 242–246, July–August, 2005. 相似文献
20.
周其凤等曾报道聚丙烯酸[2,5-双(对甲氧基苯甲酰氧基)节酯][1]和聚甲基丙烯酸[2,5-双(对甲氧基苯甲酰氧基)苄酯][2]的合成.但后来的研究发现,在合成单体的条件下出现的一种未见报道的异常反应[3]使产物成分复杂化,因此当时报道的聚合物可能不是聚丙烯酸[2,5-双-(对甲氧基苯甲酰氧基)苄酯]或聚甲基丙烯酸[2,5-双(对甲氧基苯甲酰氧基)苄酯],而可能是共聚物.针对这一问题,我们重新设计了合成路线以避免发生上述副反应,成功地合成了丙烯酸或a-甲基丙烯酸[2,5-双-(对甲氧基苯甲酰氧基… 相似文献