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1.
The copolymerization of acrylamide (AM) with sodium 3-(N-propyl)acrylamido-3-methlbutanoate (NaPAMB) has been studied in the range from 40 to 90% AM in the feed. The copolymer compositions have been determined from elemental analysis and 13C NMR. Reactivity ratio studies have been performed, and the value of r1r2 determined to be 0.36. The molecular weights, as determined by low-angle laser light scattering of the copolymers, were found to decrease sharply with increasing NaPAMB content, and were in the range 0.5–7.0 × 106. The copolymer microstructures, including mean sequence length distributions, were calculated from the reactivity ratios. Knowledge of polymer composition, micro-structure, and molecular weight is utilized for assessment of structure/dilute solution property relationships reported in a subsequent paper in this series.  相似文献   

2.
Copolymers of acrylamide (AM, M 1) with sodium 3-acrylamido-3-methylbutanoate (NaAMB, M 2) synthesized in 1 M NaCl (the ABAM2 series) are compared to those synthesized in deionized water (the ABAM1 series). At fixed feed ratios, higher incorporation rates were found for NaAMB with increasing ionic strength of the polymerization solvent. Reactivity ratios calculated by the methods of Kelen-Tüdös changed from r 1 = 1.23 and r 2 = 0.50 in deionized water to r 1 = 1.00 and r 2 = 0.64 in 1 M NaCl. This change is in accord with a decrease in electrostatic repulsion between the macroradical and unreacted NaAMB. Dilute solution properties, examined as a function of composition and added electrolytes, indicate differences in microstructure for the ABAM1 and ABAM2 copolymers.  相似文献   

3.
疏水缔合水溶性聚合物AO的溶液粘度行为研究   总被引:2,自引:1,他引:2  
研究了稀溶液中疏水链链长、无机电解质NaCl和CaCl2对疏水缔合水溶性丙烯酰胺/甲基丙烯酰氨乙基-二甲基烷基溴化铵/丙烯酸钠共聚物(AO)在水溶液中的特性粘数和Huggins常数的影响,以及聚合物AO-8的特性粘数和Huggins常数随温度的变化。结果表明:在稀溶液中,无机电解质离子强度增大,共聚物AO在NaCl和CaCl2溶液中的特性粘数减小,Huggins常数增大。在亚浓溶液范围对聚合物质量分数、温度、剪切速率及NaCl含量对聚合物的水溶液表现粘度的影响进行了研究,观察到疏水缔合聚合物盐水溶液在NaCl含量提高的情况下,出现的增粘现象。  相似文献   

4.
丙烯酰胺和表面活性大单体共聚物的合成及其性能研究   总被引:8,自引:0,他引:8  
许国强  黄雪红 《合成化学》1999,7(2):182-186
首先合成表面活性大分子单体丙烯酸聚氧乙烯(23)-十二烷基酯(AA-POELE),再通过与丙烯酰胺共聚合的方法得到在水溶性聚合物聚丙烯酰胺分子结构中引入疏水基团的共聚物改性PAM。因AA-OPELE单体具有表面活性,所以共聚合时无需添加乳化剂。当改性PAM中疏水基团含量为1.10mol%时,其水溶液表现出独特的流变性和增稠性,着重讨论了改性PAM作为乳胶增稠剂的性能。  相似文献   

5.
Water-soluble 2,3-dihydroxypropylcellulose-polyacrylamide graft copolymers (DHPC-g-PAM) were prepared by Ce4+ ion-initiated graft copolymerization of acrylamide (AM) onto 2,3-dihydroxypropylcellulose (DHPC) dissolved in dilute nitric acid at room temperature under argon. The ratios of the concentration of Ce4+ ion to the concentration of DHPC were shown to affect the number and the length of the polyacrylamide grafts. The average number of grafts per chain was determined by acid-catalyzed degradation of the cellulose backbone and was found to be consistent with the presence or absence of free DHPC in the polymerization product prior to hydrolysis. The average number of grafts per DHPC molecule was found to be 2.7 or less depending on the reaction conditions.  相似文献   

6.
采用沉淀聚合法制备水溶性的丙烯酰胺-丙烯酸十六疏水缔合型共聚物,研究了共聚物水溶液的性质及其影响因素。随着疏水基团含量增加,共聚物在纯水中及NaCl溶液中的特性粘数[η]均减小,疏水基团临界缔合浓度降低。共聚物溶液浓度高于监界缔合浓度时,溶液表现粘度急剧增加,表明溶液中分子间缔合大量形成。  相似文献   

7.
The kinetics of thermal degradation of commercial samples of copolymers of acrylamide with sodium acrylate of various molecular characteristics in water and 1.5% NaCl aqueous solutions at 40–80°C was studied viscometrically.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 1016–1020.Original Russian Text Copyright © 2005 by V. Kurenkov, Trofimov, A. Kurenkov, Khartan, Lobanov.  相似文献   

8.
丙烯酰胺共聚合及产物分散性的研究   总被引:1,自引:0,他引:1  
采用水溶性引发体系研究了丙烯酰胺的均聚以及与几种乙烯基单体的共聚反应。探讨了引发剂、温度、单体浓度及加热时间对所得聚合物相对分子质量及其分散性能的影响。对产物的结构特性和相对分子质量分布进行了表征,并考察了共聚物的分散性能。丙烯酰胺共聚物同均聚物相比,分散性能有明显的改善。  相似文献   

9.
Phase separation in aqueous solutions of binary copolymers of acrylamide with sodium 2-acryl-amido-2-methylpropanesulfonate and sodium acrylate is studied over the temperature range from 20 to 100°C, as influenced by addition of calcium, magnesium, and sodium chlorides, inorganic salt concentration, and molecular characteristics of the copolymers.  相似文献   

10.
(丙烯酰胺-丙烯酸十六酯)共聚物的合成及其增稠性能研究   总被引:2,自引:0,他引:2  
采用沉淀聚合法合成丙烯酰胺 -丙烯酸十六酯共聚物。重点讨论了合成条件如单体配比、引发剂用量、温度等对共聚反应的影响以及共聚物对苯丙乳胶的增稠性能的影响。并用DMTA和凯达尔定氮法表征了共聚物组成 ,结果表明 :所合成的共聚物可以作为疏水缔合型增稠剂使用  相似文献   

11.
Dilute solution properties of copolymers of acrylamide (AM) with sodium-3-acrylamido-3-methylbutanoate (NaAMB) of known molecular weight have been studied as a function of composition, temperature, time, pH, and added electrolytes. Phase separation and potentiometric studies have also been performed. The AM–NaAMB copolymers exhibit high solution viscosities, good salt tolerance, and moderate viscosity-temperature coefficients. In addition, these copolymers exhibit no phase separation in the presence of divalent cations as is common with many such carboxylated polyelectrolytes. These properties are due to favorable conformations in solution resulting from microstructure and hydrogen bonding effects.  相似文献   

12.
The synthesis and semiconcentrated and dilute solution properties of two series of ampholytic acrylamide ionomers, poly(acrylamide MPTMA/AMPS) and poly(acrylamide METMA/MES), are reported as a function of the ionic content and added salt concentration. The viscosity dependence on shear rate was measured with a cone/plate Brookfield viscometer for sermiconcentrated solution and with a Cannon-Ubbelohde four-bulb shear dilution capillary viscometer for dilute solution at 25 ± 0.1°C. The two series of ampholytic acrylamide ionomers showed a characteristic pseudoplastic shear-thinning behavior under both conditions. The semiconcentrated solution viscosity parameters m and n in the power-law model, η = mγn-1, were determined and found to be functions of the ionic content. The viscosity at selected shear rates was found to be a complex function of the salt concentration. The intrinsic viscosity [η] was determined and compared with molecular parameters determined by light scattering under identical conditions. The dilute-solution properties of the ampholytic ionomers were found to resemble the properties of neutral polyacrylamide previously reported in the literature.  相似文献   

13.
Lysine, which is an amino acid with a basic side group, is present in biological fluids and its role in the biological calcification process was investigated. It was found to inhibit the crystal growth rate of hydroxyapatite (HAP), in solutions supersaturated only with respect to this calcium phosphate salt and this rate reduction was attributed to adsorption and further blocking of the active growth sites on the crystal surface. The crystallization kinetics were interpreted in terms of the Langmuir adsorption model. The apparent order of the crystallization reaction was found to be n=2, suggesting a surface diffusion controlled spiral growth mechanism. Kinetic results of HAP crystallization were obtained using the constant composition method where the concentration of the reactants is kept constant during the course of the crystal growth experiment. Copyright 2000 Academic Press.  相似文献   

14.
Thermal transformations of sodium 2-acrylamido-2-methylpropanesulfonate-N-vinylpyrrolidone copolymers of various chemical compositions were studied by thermogravimetric, differential thermal, and thermomechanical analyses within 20-600°C in air. The thermal degradation parameters in various temperature ranges were estimated, as well as the heat resistance of the copolymers.  相似文献   

15.
Dilute solution properties of copolymers of acrylamide (AM) with N-(1,1-dimethyl-3-oxybutyl)acrylamide (DAAM) and with N,N-dimethylacrylamide (DMAM) have been studied as a function of composition, temperature, time, and added electrolytes sodium chloride and calcium chloride. Unlike the AM-DMAM copolymers, the AM-DAAM copolymers show solution viscosity increases in the presence of added NaCl and CaCl2 and decreases with increasing temperature which are related to copolymer composition. The unusual viscosity behavior of the DAAM-AM copolymers is suspected to be due to chain extension resulting from intramolecular hydrogen bonding and other cooperative associations along the macromolecular backbone.  相似文献   

16.
A novel difluoride containing carbazole groups was designed. Two series of polycarbazoles based on the novel monomer were synthesized via C-N coupling reactions with either 4,4′-biphenol or bisphenol A. Copolymers were obtained with 4,4′-difluorobenzophenone or bis(4-fluorophenyl) sulfone as comonomer. The solubilities of the poly(carbazole ketones)s were poor, but the poly(carbazaole sulfones)s all dissolved in NMP, DMSO and DMAC. Tough films of poly(carbazole sulfones)s could be easily cast from NMP solutions. The viscosities of poly(carbazole sulfones)s were 0.72 ~ 0.90 dL/g. The Tgs of polymers ranged from 162.4°C to 258.9°C. The temperatures of 5% wt loss ranged from 460°C to 509°C. UV-Vis absorptions and blue light emissions properties are also presented.  相似文献   

17.
共聚物红外光谱的小波变换   总被引:5,自引:0,他引:5  
陈洁  单军 《分析化学》1997,25(2):172-174
用傅里叶变换红外光谱研究了辐射合成的丙烯酰胺、丙烯酸钠均聚物水凝胶和几种丙烯酰胺/丙烯酸钠配比不同的共的水凝胶的组成变化,发现共聚物的特征吸收带重叠得比较严重,尤其当丙烯酸单元含量较代时,其特征吸收带大部分则不能分辨,将其红外光谱经波波变换后,这类共聚物的特征吸收带较好地得到分离,成功地提高了红外光谱图的分辨率,有助于更好地定性或定量表征共聚物的组成。  相似文献   

18.
In order to develop polymers useful as mobility control agents in enhanced oil recovery processes, water-soluble acrylamide grafted polysaccharide copolymers have been synthesized in water at 25° C using a ceric ammonium nitrate/nitric acid system. The effects of varying concentrations of ceric ion, monomer, and substrate on conversion, graft length, and molecular structure of the reaction products have been examined. The crude reaction products were purified by fractional precipitation and then were analyzed for nitrogen content using a micro-Kjeldahl method. The chemical structures of the graft copolymers were studied by selective hydrolysis of the carbohydrate backbones. Intrinsic viscosity and grafting length data were used to predict solution behavior of the graft copolymers prepared under controlled conditions. Aqueous size exclusion and viscosity studies showed direct correlations between hydrodynamic volume and length of the polyacrylamide side-chain grafts.  相似文献   

19.
Thermal stability, impact strength, folding resistance, and adhesion were studied for copolymers of vinyl chloride and 1-(vinyloxyalkoxy)propylene 2,3-oxides prepared in acetone and dimethyl sulfoxide.  相似文献   

20.
疏水改性水溶性聚合物/表面活性剂溶液性质   总被引:6,自引:0,他引:6  
表面张力;疏水改性水溶性聚合物/表面活性剂溶液性质  相似文献   

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