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1.
Differential scanning calorimetry (DSC) of triple blends of high molecular weight poly(N‐vinyl pyrrolidone) (PVP) with oligomeric poly(ethylene glycol) (PEG) of molecular weight 400 g/mol and copolymer of methacrylic acid with ethylacrylate (PMAA‐co‐EA) demonstrates partial miscibility of polymer components, which is due to formation of interpolymer hydrogen bonds (reversible crosslinking). Because both PVP and PMAA‐co‐EA are amorphous polymers and PEG exhibits crystalline phase, the DSC examination is informative on the phase state of PEG in the triple blends and reveals a strong competition between PEG and PMAA‐co‐EA for interaction with PVP. The hydrogen bonding in the triple PVP–PEG–PMAA‐co‐EA blends has been established with FTIR Spectroscopy. To evaluate the relative strengths of hydrogen bonded complexes in PVP–PEG–PMAA‐co‐EA blends, quantum‐chemical calculations were performed. According to this analysis, the energy of H‐bonding has been found to diminish in the order: PVP–PMAA‐co‐EA–PEG(OH) > PVP–(OH)PEG(OH)–PVP > PVP–H2O > PVP–PEG(OH) > PMAA‐co‐EA–PEG(? O? ) > PVP–PMAA‐co‐EA > PMAA‐co‐EA–PEG(OH). Thus, most stable complexes are the triple PVP–PMAA‐co‐EA–PEG(OH) complex and the complex wherein comparatively short PEG chains form simultaneously two hydrogen bonds to PVP carbonyl groups through both terminal OH‐groups, acting as H‐bonding crosslinks between longer PVP backbones. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

2.
The specific interactions in ternary 4‐hydroxybenzoic acid (HBA)/poly(2‐vinylpyridine) (P2VPy)/poly(N‐vinyl‐2‐pyrrolidone) (PVP) blends were studied by differential scanning calorimetry, Fourier transform infrared (FTIR) spectroscopy, and electron microscopy. FTIR study shows the existence of hydrogen‐bonding interactions between HBA and P2VPy as well as PVP. The addition of a sufficiently large amount of HBA produces a blend showing one glass‐transition temperature (Tg). Microscopic study shows a drastic reduction in domain size in single‐Tg blends. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 901–907, 2001  相似文献   

3.
Differential scanning calorimetry and inverse gas chromatography have been used to investigate the miscibility behaviour of blends of poly(ethyl methacrylate) (PEMA) with styrene–cinnamic acid statistical copolymers PSCA5, PSCA8, PSCA23 having compositions of, respectively, 5, 8 and 23 mol% of cinnamic acid. Several probes with different chemical nature and polarity have been used to determine the polymer–solute and polymer–polymer interaction parameters. DSC and CPGI measurements indicate that poly(ethyl methacrylate) is miscible with each poly[(styrene)‐co‐(cinnamic acid)] copolymer as established from the observation of a single composition‐dependent glass transition temperature. This deduction is corroborated by the IGC data; comparison of the experimental retention volume of the blend with the algebraic average retention volumes of the pure components, together with negative values of the apparent polymer–polymer interaction parameter, establish the miscibility of the studied systems. Furthermore, the polymer–polymer interaction parameters are found to show marked probe dependence; this is discussed in terms of the Δχ effect. As indicated by the variation of the glass transition temperature with blend composition, the application of the Kwei and the Schneider approaches to the calorimetric results suggests the occurrence of strong specific interactions within the blends; the strength of these intermolecular interactions increases with the cinnamic acid content in the PSCA copolymer. © 2001 Society of Chemical Industry  相似文献   

4.
The molecular interactions between the component networks in poly(methacrylic acid)/poly(N‐isopropyl acrylamide) (PMAA/PNIPAAm) interpenetrating polymer networks (IPNs) were investigated using attenuated total reflectance (ATR)‐Fourier transform IR (FTIR) spectroscopy. Hydrogen‐bond formation was noted between the carboxyl groups of PMAA and the amide groups of PNIPAAm. The ATR‐FTIR results showed shifts in the carboxylic and amide groups, indicating the existence of hydrogen bonding between these two individual networks within the IPNs. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1077–1082, 2001  相似文献   

5.
A novel polysaccharide‐based polyelectrolyte complex was formed via ionic self‐assembly (ISA) of a carboxylic derivative of starch, maleic starch half‐ester acid (MSA), with chitosan (CS) and precipitated from aqueous solution. Both Fourier transform infrared (FTIR) spectroscopy and elementary analysis results showed that there was CS in the complex. Thermogravimetric analysis (TGA) showed that the thermal resistance of the complex was higher than that of two components and the corresponding blend. X‐ray diffraction (XRD) analysis result revealed that the complex was amorphous, whereas its components were semi‐crystalline. In addition, the drug release behavior of the complex that contains 5‐fluorouracil behaved pH‐responsive. All the experimental results verified the complex was composed of MSA and CS, and also indicated that the driving force for the self‐assembly of the complex was predominantly the electrostatic interactions between two oppositely charged polyelectrolytes, cationic CS, and the anionic MSA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

6.
It is shown that the reaction between poly(acrylic acid) and a non‐ionic polymer may give two different products. One of them is the well‐known interpolymer complex stabilized by hydrogen bonds, and the other belongs to a relatively new class of compounds named hydrophilic interpolymer associates. Networks occurring in the dynamic mode of formation and destruction of hydrogen bond linkages represent the structure of the hydrophilic associates; a single molecule of polyacid may be linked with two or more molecules of non‐ionic polymer in such associates. The result of the reaction under consideration strongly depends on the ratio of volumes of swollen coils of ionogenic and electrically neutral macromolecules. Classical interpolymer complexes cannot be formed at a high degree of swelling of polyacid coils, which takes place at high pH values. In contrast, hydrophilic associates are formed under such conditions. © 2013 Society of Chemical Industry  相似文献   

7.
The miscibility of poly(n‐butyl methacrylate‐co‐methacrylic acid) containing 18 mol % methacrylic acid (BMAM‐18) and poly(styrene‐coN,N‐dimethyl acrylamide) containing 17 mol % N,N‐dimethyl acrylamide (SAD‐17) was investigated with viscometry, differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. The DSC analysis showed a single glass‐transition temperature for all the blends, indicating that these copolymers were miscible over the entire composition range. The glass‐transition temperatures of these blends were higher than those calculated with the additivity rule. This was characteristic of the presence of specific interactions. The interactions between BMAM‐18 and the tertiary amide of SAD‐17 were studied with FTIR spectroscopy, which revealed that hydrogen‐bonding interactions occurred between the hydroxyl groups of BMAM‐18 and the carbonyl amide of SAD‐17. A new band characterizing these interactions appeared around 1613 cm?1. The quantitative results showed that the fraction of the associated amide increased with an increase in the amount of the acidic BMAM‐18 copolymer. Although BMAM‐18 and SAD‐17 led to homogeneous solutions in butan‐2‐one, as the concentration of N,N‐dimethyl acrylamide increased to 32 mol % [as within the poly(styrene‐coN,N‐dimethyl acrylamide) containing 32 mol % N,N‐dimethyl acrylamide], complexation occurred when this latter compound was mixed with BMAM‐18 in butan‐2‐one. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2717–2724, 2006  相似文献   

8.
Macroporous amphoteric cryogels based on N,N‐dimethylaminoethylmethacrylate and methacrylic acid p(DMAEM‐co‐MAA) crosslinked by N,N′‐methylenebisacrylamide (MBAA) were synthesized by radical copolymerization of monomer mixtures in cryoconditions. The structure and morphology of cryogels were evaluated by FTIR and SEM. Cryogels exhibited interconnected porous structure with pore size ranging from 40 to 80 µm, which depended on their crosslinking degree. The value of the isoelectric point (IEP) of equimolar amphoteric cryogel determined from the water flux was equal to 4.4, while the IEP of cryogel with the excess of DMAEM units was equal to 7.1. The mechanical strength of equimolar amphoteric cryogels increases with increasing amount of crosslinking agent. The complexation ability of amphoteric cryogels with respect to surfactant, dyes, and protein was demonstrated. The adsorption isotherms with respect to anionic surfactant—sodium dodecylbenzene sulfonate (SDBS) and protein—lysozyme correspond to Langmuir equation, while adsorption isotherms of anionic and cationic dyes—methylene blue (MB) and methyl orange (MO) are well described by Freundlich equation. It was found that the binding ability of p(DMAEM‐co‐MAA) with respect to various low‐ and high‐molecular weight compounds changes in the following order: SDBS > lysozyme ? MO > MB. The preferential adsorption of MB from the mixture of protein and MB was shown. The quantitative release of protein, surfactant and dye molecules from the matrix of cryogels takes place at the IEP of cryogel. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43784.  相似文献   

9.
The metal‐ion complexation behavior and catalytic activity of 4 mol % N,N′‐methylene bisacrylamide crosslinked poly(acrylic acid) were investigated. The polymeric ligand was prepared by solution polymerization. The metal‐ion complexation was studied with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), and Zn(II) ions. The metal uptake followed the order: Cu(II) > Cr(III) > Mn(II) > Co(II) > Fe(III) > Zn(II) > Ni(II). The polymeric ligand and the metal complexes were characterized by various spectral methods. The catalytic activity of the metal complexes were investigated toward the hydrolysis of p‐nitrophenyl acetate (NPA). The Co(II) complexes exhibited high catalytic activity. The kinetics of catalysis was first order. The hydrolysis was controlled by pH, time, amount of catalyst, and temperature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 272–279, 2004  相似文献   

10.
The miscibility or complexation of poly(styrene‐co‐acrylic acid) containing 27 mol % of acrylic acid (SAA‐27) and poly(styrene‐coN,N‐dimethylacrylamide) containing 17 or 32 mol % of N,N‐dimethylacrylamide (SAD‐17, SAD‐32) or poly(N,N‐dimethylacrylamide) (PDMA) were investigated by different techniques. The differential scanning calorimetry (DSC) analysis showed that a single glass‐transition temperature was observed for all the mixtures prepared from tetrahydrofuran (THF) or butan‐2‐one. This is an evidence of their miscibility or complexation over the entire composition range. As the content of the basic constituent increases as within SAA‐27/SAD‐32 and SAA‐27/PDMA, higher number of specific interpolymer interactins occurred and led to the formation of interpolymer complexes in butan‐2‐one. The qualitative Fourier transform infrared (FTIR) spectroscopy study carried out for SAA‐27/SAD‐17 blends revealed that hydrogen bonding occurred between the hydroxyl groups of SAA‐27 and the carbonyl amide of SAD‐17. Quantitative analysis carried out in the 160–210°C temperature range for the SAA‐27 copolymer and its blends of different ratios using the Painter–Coleman association model led to the estimation of the equilibrium constants K2, KA and the enthalpies of hydrogen bond formation. These blends are miscible even at 180°C as confirmed from the negative values of the total free energy of mixing ΔGM over the entire blend composition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1011–1024, 2007  相似文献   

11.
The heat‐resistant copolymer of N‐phenylmaleimide (NPMI)–styrene (St)–maleic anhydride (MAH) was synthesized in xylene at 125°C with di‐tert‐butyl diperoxyterephthalate as an initiator. The characteristics of the copolymer were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy (1H‐NMR and 13C‐NMR), gel permeation chromatography, and elemental analysis. The 13C‐NMR results show that the copolymer possessed random sequence distribution; this was also supported by the differential scanning calorimetry experiment, in which a single glass‐transition temperature (Tg) of 202.3°C was observed. The thermal stability and degradation mechanism of the copolymer were investigated by thermogravimetric analysis. Using the Kissinger equation and Ozawa equation, we proved a nucleation controlling mechanism with an apparent activation energy of 144 kJ/mol. Blends of acrylonitrile–butadiene–styrene with the NPMI–St–MAH copolymer with various contents were prepared with a twin‐screw extruder processes. The mechanical and thermal properties of the materials, such as the tensile and flexural strength, Tg's, and Vicat softening temperatures, were all enhanced with the addition of the modifier, whereas the melt flow index decreased. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

12.
Summary: This paper reports an FT‐IR study of blends and complexes of poly(mono n‐alkyl itaconates) with poly(N,N‐dimethylacrylamide) (PDMA) and poly(ethyloxazoline) (PEOX). Strong hydrogen bonding has been found and both polybases have shown similar acceptor strengths. The extent of the interassociation has been estimated by spectral curve fitting of the polybase carbonyl band. The influences of the solvent medium and alkyl side group length of the poly(mono n‐alkyl itaconate) on the interassociation extents have been discussed. Blend and complex interassociation behavior has been compared too. Results show that media influences the interassociation degree in systems with PDMA, but has negligible influence in systems with PEOX. Moreover, the interassociation degree in blends with PEOX does not depend on the length of the poly(monoalkyl itaconate) side group, while an interassociating ability loss is observed in blends with PDMA as the side group size of the polyacid increases. This different behavior is attributed to the greater interspacing between vicinal carbonyl groups in PEOX. Anyway, this band shows conformational sensitivity and reflects the conformational changes that are forced to adopt as the steric hindrances present in the medium (due to the bulky side groups of the polyacids) increase.

Auto scaled carbonyl stretching region for PMBuI/PEOX complexes.  相似文献   


13.
We carried out the free‐radical copolymerization of N‐phenylmaleimide with acrylic acid and acrylamide with an equimolar feed monomer ratio. We carried out the synthesis of the copolymers in dioxane at 70°C with benzoyl peroxide as the initiator and a total monomer concentration of 2.5M. The copolymer compositions were obtained by elemental analysis and 1H‐NMR spectroscopy. The hydrophilic polymers were characterized by elemental analysis, Fourier transform infrared spectroscopy, 1H‐NMR spectroscopy, and thermal analysis. Additionally, viscosimetric measurements of the copolymers were performed. Hydrophilic poly(N‐phenylmaleimide‐co‐acrylic acid) and poly(N‐phenylmaleimide‐co‐acrylamide) were used for the separation of a series of metal ions in the aqueous phase with the liquid‐phase polymer‐based retention method in the heterogeneous phase. The method is based on the retention of inorganic ions by the polymer in conjunction with membrane filtration and subsequent separation of low‐molecular‐mass species from the formed polymer/metal‐ion complex. The polymer could bind several metal ions, such as Cr(III), Co (II), Zn(II), Ni(II), Cu(II), Cd(II), and Fe(III) inorganic ions, in aqueous solution at pH values of 3, 5, and 7. The interaction of the inorganic ions with the hydrophilic polymer was determined as a function of pH and a filtration factor. Hydrophilic polymeric reagents with strong metal‐complexing properties were synthesized and used to separate those complexed from noncomplexed ions in the heterogeneous phase. The polymers exhibited a high retention capability at pH values of 5 and 7. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006  相似文献   

14.
A polyelectrolyte complex hydrogel, poly (N,N‐dimethylaminoethyl methacrylate/acrylic acid‐co‐acrylamide) hydrogel designed as PDMEAA, was prepared by the free radical copolymerization in aqueous solutions. Without chemical crosslinker, PDMEAA hydrogel network was formed by electrostatic attraction of the proton‐transfer between acrylic acid and N,N‐dimethylamino ethyl methacrylate. Since the electrostatic attraction could be weakened by the application of electric field, PDMEAA hydrogel was decomposed under contacted electric field. Various factors such as gel composition, the species and concentration of electrolytes, voltage, and the experimental set‐ups, could effect the decomposing process of PDMEAA hydrogel. In CaCl2 and MgCl2 solutions, PDMEAA hydrogel had no change under electric field. And in high concentration of NaCl and Na2SO4 solutions, PDMEAA hydrogel has been eroded linearly with the increasing time applied electric field. In low concentration of NaCl and Na2SO4 solutions, however, a swelling process was found before the erosion. The stimuli‐responsive mechanism was investigated through scanning electron microscope (SEM) and gel permeation chromatography (GPC). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

15.
The crosslinked poly[N‐(3‐dimethylamino)propylmethacrylamide] [P(NDAPA)] and poly[N‐(3‐dimethylamino)propylmethacrylamide‐co‐acrylic acid] [P(NDAPA‐co‐AA)] were synthesized by radical polymerization. The resins were completely insoluble in water. The metal‐ion‐uptake properties were studied by a batch equilibrium procedure for the following metal ions: silver(I), copper(II), cadmium(II), zinc(II), lead(II), mercury(II), chromium(III), and aluminum(III). The P(NDAPA‐co‐AA) resin showed a lower metal‐ion affinity than P(NDAPA), except for Hg(II), which was retained at 71% at pH 2. At pH 5, the resin showed a higher affinity for Pb(II) (80%) and Cu(II) (60%), but its affinity was very low for Zn(II) and Cr(III). The polymer ligand–metal‐ion equilibrium was achieved during the first 20 min. By changing the pH, we found it possible to remove between 60 and 70% of Cd(II) and Zn(II) ions with (1M, 4M) HClO4 and (1M, 4M) HNO3. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5232–5239, 2006  相似文献   

16.
Syndiotactic poly(methacrylic acid) (Syn‐PMAA, r diad = 91 mol %) was synthesized by free radical polymerization of methacrylic acid (MAA) with catechol. The pseudo‐divinyl monomer was formed with one catechol and two MAA molecules by the hydrogen bonding between OH groups of catechol and COOH group of MAA. When the free radical polymerization of the pseudo‐divinyl monomer was carried out, intra‐ and intermolecular addition proceeded with racemic addition. The hydrogen bonding was the driving force to control tacticity. We discussed the effects of solvent, temperature, and the concentrations of MAA and catechol on the pseudo‐divinyl monomer formation. The highly syndiotactic PMAA was successfully obtained. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

17.
Coloring study in organic hybrid of polyamide (PA6) and N,N′‐ethylene‐bis(tetrabromophthalimide) (EPT), where the chromophore was self‐assembled by hydrogen bonding formed between PA6 molecular chains and EPT compound, have been characterized by several techniques. CS930 double wavelength lamella scanner was employed to measure the change of color. The existence of hydrogen bonding in PA6/NN′‐ethylene‐bis (tetrabromophthalimide) (PA6EPT) was investigated with Fourier transform infrared (FTIR), the results of which were compared with that of PA6 with the same thermal history. FTIR spectra at room temperature revealed that there is essentially hydrogen bonding between PA6 and EPT. The crystallization behavior of PA6EPT affected by hydrogen bonding was studied by using FTIR. The temperature‐dependent behavior of both PA6 and PA6EPT was studied by temperature‐FTIR spectroscopy and differential scanning calorimetry (DSC). With temperature increasing, changes in sensitive, high‐resolution absorbance spectra are observed as dissolve‐volatilizing thin film. Temperature‐FTIR results showed that the hydrogen bonding in PA6EPT attenuated and dissociated considerably at a smaller rate than PA6, that is to say, hydrogen bonding in PA6EPT is more stable than that in PA6. DSC showed that the melting temperature of PA6EPT and PA6 are similar. However, the crystalline degree and crystalline temperature and melting enthalpy of PA6 and PA6EPT are different. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 594–600, 2007  相似文献   

18.
Poly(vinylamine hydrochloride‐coN‐vinylformamide) [poly(VAm‐co‐NVF)] with variable VAm content, and a weak polyacid poly(acrylic acid) were assembled on a quartz crystal microbalance (QCM) substrate from their aqueous solutions, thus forming polyelectrolyte multilayers. The effects of varying the VAm content on assembly profiles and film structures were analyzed by quantitative QCM analysis, attenuated total reflection spectra techniques, and atomic force microscopic observation. At a VAm content of less than 40% of the total number of poly(VAm‐co‐NVF) units, the layer‐by‐layer assembly did not proceed, and the frequency shift of the QCM zigzagged with the step number. Above 40% VAm content, the frequency increased continuously with an increasing number of steps. The assembly amount was also maximal at 40% VAm content. The films obtained swelled with water molecules, and this swelling was followed by an increase in thickness in the aqueous phase. The results obtained were compared to those obtained from a combination of poly(VAm‐co‐NVF) and a strong polyacid, poly(sodium styrenesulfonate). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3927–3933, 2006  相似文献   

19.
Yi Dan  Qi Wang 《Polymer International》2001,50(10):1109-1114
A homogeneous complex solution, formed through inter‐polyelectrolyte complexation of poly(acrylamide‐co‐acrylic acid) (P(AM‐AA)) with poly(acrylamide‐co‐dimethyldiallylammonium chloride) (P(AM‐DMDAAC)) and interaction of the P(AM‐AA)/P(AM‐DMDAAC) complex with M n+ hydrated metal ion, was prepared and the structure and properties of the P(AM‐AA)/P(AM‐DMDAAC)/M n+ homogeneous complex solution were studied by UV spectrometry, dynamic light scattering and viscometry. The experimental results show that the homogeneous complex solution can be obtained by controlling the composition of the P(AM‐AA)/P(AM‐DMDAAC) complex and the M n+ metal ion content. Compared to the constituents, ie the P(AM‐AA) solution, the P(AM‐DMDAAC) solution and the P(AM‐AA)/P(AM‐DMDAAC) complex solution, the P(AM‐AA)/P(AM‐DMDAAC)/M n+ complex solution has a new peak at 270 nm in its UV spectrum, a larger hydrodynamic radius, and hence a higher solution viscosity, all of which indicate that there exist specific interactions between polymers and M n+ metal ions. These interactions lead to the formation of a network structure and hence an obvious increase not only in solution viscosity but also in resistance of the polymer solution to simple salts, to temperature changes and to shearing. © 2001 Society of Chemical Industry  相似文献   

20.
Monomers of diacylated amine were synthesized by the reaction of acryloyl chloride or methacryloyl chloride with p‐phenylenediamine. Heating DMF solution of these monomers at 75°C in the presence of AIBN as an initiator gave the corresponding polymer. The solid metallopolymer complexes with different metal salts were isolated either by the in situ addition of the monomer, metal salt, and initiator at 75°C or by the reaction of the isolated polymer with the metal salt at 150°C. The monomers, polymers, and their metallopolymer compounds were characterized using elemental analysis, IR, NMR (1H and 13C), and MS spectral measurements in addition to thermal analysis. The IR data showed that the coordinating atoms of the polymer are dependent on the reaction temperature. The ion selectivity of the isolated polymers toward different metal ions either for a single metal ion or in a mixture as aqueous solutions are studied by the batch techniques. Energy dispersive spectroscopy (EDS) measurements showed that both polymers are more selective to Hg2+ and Pb2+. The morphology of the polymers and their metallopolymer complexes at different temperature was also studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2412–2422, 2006  相似文献   

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