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1.
Synthesis of superabsorbent hydrogel (SAHG) of acrylic acid‐potassium acrylate copolymer by direct Ultraviolet (UV) photopolymerization is a new method. The effects of degree of neutralization of acrylic acid (AA), photoinitiators, crosslinking agents, and exposure time of UV light on water absorbent properties were investigated. The results showed that the water absorbency (Q) and the salt solution (NaCl, 0.9%) absorbency (Qs) of SAHG, based on Irgacure 651, are high, reaching about 1400 and 130 mL/g, respectively. UV absorption spectrum proved that peak of UV absorption of Irgacure 651 matched the UV light source we used. Among the crosslinking agents, N,N′‐methylene bisacrylamide is more efficient than others, because of its very small content and high Q. 13C NMR spectrometry was used to identify the mechanism of crosslinking reaction through esterification of hydroxyethyl acrylate (HEA) and 2‐hydroxypropyl acrylate (HPA) with carboxylic acid group in acrylic acid‐ammonium acrylate copolymerization, but efficiency of crosslinking reaction by esterification was lower than that of copolymerization of vinyl group in crosslinking agent. The Q of acrylic acid‐potassium acrylate copolymer of SAHG reaches 1592 mL/g under the following conditions: degree of neutralization of acrylic acid is 80%, content of Irgacure 651 is 0.25 wt %, content of HEA is 0.2 wt %, and exposure time is 10 min. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1181–1187, 2006 相似文献
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Acrylate‐functionalized copolymers were synthesized by the modification of poly(butyl acrylate‐co‐glycidyl methacrylate) (BA/GMA) and poly(butyl acrylate‐co‐methyl methacrylate‐co‐glycidyl methacrylate). 13C‐NMR analyses showed that no glycidyl methacrylate block longer than three monomer units was formed in the BA/GMA copolymer if the glycidyl methacrylate concentration was kept below 20 mol %. We chemically modified the copolymers by reacting the epoxy group with acrylic acid to yield polymers with various glass‐transition temperatures and functionalities. We studied the crosslinking reactions of these copolymers by differential scanning calorimetry to point out the effect of chain functionality on double‐bond reactivity. Films formed from acrylic acrylate copolymer precursors were finally cured under ultraviolet radiation. Network heterogeneities such as pendant chains and highly crosslinked microgel‐like regions greatly influenced the network structure and, therefore, its viscoelastic properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 753–763, 2002 相似文献
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Synthesis of superabsorbent resin (SAR) was achieved by a new method, that of direct UV photopolymerization, and in particular the synthesis of a SAR of acrylic acid–potassium acrylate copolymer by UV photopolymerization was investigated. Influences of ratio (mol) of acrylate monomer to acrylic acid monomer, photoinitiators, crosslinking agents, and exposure time of UV light on the water‐absorbent properties were investigated. The results showed that the water absorbency (Q) of SAR based on Irgacure 1700 or Irgacure 1800 was 545–530 mL/g, but under the same conditions Q was 450 mL/g for the SAR based on Irgacure 651. N,N′‐Methylene bisacrylamide, hydroethyl acrylate, and glycerol were used as crosslinking agents, of which N,N′‐methylene bisacrylamide was the most effective. It crosslinked the molecular chains through attending the copolymerization with acrylic acid (AA) and potassium acrylate. When the exposure time was 5 min, the value of Q was 1368 mL/g (the content of N,N′‐methylene bisacrylamide was 100 ppm). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1618–1624, 2004 相似文献
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A new kind of macrophotoinitiator (MPI) was synthesized through the copolymerization of acrylic monomers and the polymerizable photoinitiator monomer 2959‐AA. Monomer 2959‐AA was obtained by an esterification reaction between acrylic acid (AA) and the water‐soluble photoinitiator Irgacure 2959 [2‐hydroxy‐4‐(2‐hydroxyethoxy)‐2‐methylpropiophenone]. By adjusting the monomer proportions in the MPIs, two series of MPIs with different 2959‐AA contents and different glass transition temperatures were obtained. The molecular structure of 2959‐AA was characterized by Fourier‐transform infrared spectroscopy, nuclear magnetic spectrometry, and mass spectrometry. Polymerization of 1, 6‐hexanediol diacrylate was initiated using Irgacure 2959 and 2959‐AA, and two series of MPIs to be polymerized were studied with a photo‐DSC test. Results showed that 2959‐AA had higher chemical reactivity than Irgacure 2959 because of the higher solubility of the former. It was evident from the experiments that 2959‐AA content in the MPI progressively increased the polymerization rate and monomer conversion when the glass transition temperatures of MPIs were similar. At the same 2959‐AA content, the polymerization rate slightly slowed down with increased glass transition temperature. However, the radical lifetime and polymerization time were prolonged. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40352. 相似文献
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A new synthesis method of pH‐response superabsorbent hydrogels (SHG) was achieved by direct ultraviolet (UV) photopolymerization, and in particular, the synthesis of SHGs of acrylic acid (AA), sodium acrylate (AANa), and methacrylcholine chloride (MACC) tricomponent copolymer by UV photopolymerization were investigated. The pH value responsive behavior of SHG with different monomer ratios of MACC and AA was researched, and SHG showed large swelling properties at pH value approximately 7. Influences of monomer ratio (mol) of AANa to AA, photoinitiators, crosslinking agents, and exposure time of UV light on the water absorbent properties were studied. The results showed that the water absorbent capacity of SHG based on photoinitiators: Esacure KTO46 or Irgacure 651 can reach comparatively high, N,N′‐Methylene bisacrylamide and diethylene glycol diacrylate (DEGDA) were high efficient crosslinking agents for its crosslinking the molecular chains through attending the copolymerization with monomers. When the exposure time was 10 min, the distilled water absorbency of SHG was 1503 mL/g under the condition: content of MACC, 14.3 wt %; monomer ratio (mol) of AANa to AA: 5.67; content of DEGDA and Irgacure 651, 0.0025 and 0.25 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1847–1852, 2007 相似文献
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Fen Wang Lvshan Zhou Changlu Liu Xiaogang Luo 《Journal of Adhesion Science and Technology》2013,27(6):690-698
A novel porous epoxy acrylate resin monolith has been successfully prepared by low-temperature phase separation photoinitiated polymerization. The process parameters of low-temperature photopolymerization, including photoinitiators type, concentration, and sample thickness were studied. The optimum conditions for the preparation of the sample were also evaluated. The results showed that the porous morphology of the prepared monolith was affected by monomer concentration, freezing speed and temperature of the solution. The average pore size increased with increasing solvent amount, decreasing freezing temperature and speed. 相似文献
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Titania‐containing coatings were prepared through a dual‐cure process involving radical photopolymerization of a polysiloxane diacrylate and subsequent condensation of alkyltitanate groups. The kinetics of photopolymerization and condensation reaction was investigated as a function of the inorganic phase precursor (titanium tetraisopropoxide) content. AFM analysis gave evidence of a strong interaction between the organic and inorganic phase with the formation of titania domains in the nanoscale region. An increase of hydrophilicity in the coatings surface with increasing TiO2 content was evidenced. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4659–4664, 2006 相似文献
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acrylonitrile (AN)/ammonium acrylate (AAT) copolymers were prepared by H2O/dimethyl formamide suspension polymerization technique. Differential scanning calorimetry results of the degradation of AN/AAT copolymers in air are presented. The apparent activation energy of degradation of the copolymer was calculated by using Kissinger method. Effects of copolymerization conditions on the apparent activation energy of copolymer were studied. It has been found that increasing dimethyl formamide concentration in the solvent mixture leads to a rapid increase in the degradation apparent activation energy of AN/AAT copolymer. The value of the degradation apparent activation energy of the copolymer synthesized in dimethyl formamide solvent increases up to 141.7 kJ mol?1. The apparent activation energy decreases quickly, along with increase in AAT concentration, and this change becomes less prominent as the weight ratio of AAT/AN goes beyond 6/94. The apparent activation energy shows a trend of increase with increasing copolymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4649–4653, 2006 相似文献
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Preparation of bentonite–poly[(acrylic acid)‐acrylamide] water superabsorbent by photopolymerization
A novel bentonite–poly[(acrylic acid)‐acrylamide] superabsorbent composite with water and salt solution absorbencies of 450 and 108 times its own weight, respectively, was successfully synthesized by photopolymerization of acrylic acid with acrylamide in the presence of bentonite powder using 30 min of ultraviolet irradiation at room temperature. The results show a synergetic effect of Michler's ketone and benzophenone mixed photoinitiators on the water absorbency, and incorporation of bentonite below 10 wt% into the water superabsorbent can slightly increase the water and salt solution absorbencies, and improve water retention, as demonstrated using thermogravimetric analysis and differential scanning calorimetry. Fourier transform infrared spectroscopy allowed the determination of the structure of the bentonite composite superabsorbent. Copyright © 2006 Society of Chemical Industry 相似文献
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Acrylic emulsion pressure‐sensitive adhesives (PSAs) were synthesized by the copolymerization of n‐butyl acrylate with various levels of 2‐ethyl hexyl acrylate (2EHA) and a small constant amount of acrylic acid. The effect of varying the n‐butyl acrylate/2EHA monomer composition on the kinetic behavior of the polymerization and the characteristics of the copolymers prepared in a batch process were investigated. The results showed that increasing the amount of 2EHA in the monomer caused the polymerization rate and the glass‐transition temperature of the acrylic copolymers to decrease. Increasing the amount of 2EHA caused the gel content of the copolymers to decrease, reaching a minimum at 50 wt %; thereafter, the gel content increased at higher 2EHA levels. For the acrylic emulsion, the peel‐fracture energy of the PSAs decreased as the amount of 2EHA in the monomer was increased up to 50 wt %. At higher 2EHA levels, the peel‐fracture energy was relatively constant. Interestingly, a synergistic effect of increased shear resistance at 25 wt % 2EHA was observed without a significant trade‐off in terms of the peel and tack properties. This behavior was attributed to a good interconnection between the microgels and the free polymer chains inside the contacting particles in the adhesive film. Cooperation between various levels of 2EHA in the copolymer structure simultaneously changed the crosslink molecular weight (Mc) of the microgels and the entanglement molecular weight (Me) of the free chains in the adhesive network morphology. The adhesive performance of the PSAs was found to be correlated with their Mc/Me values as the 2EHA proportion was varied. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
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A weak acid acrylic resin was used as an adsorbent for the investigation of Basic Blue 3 (BB3) adsorption kinetics, isotherms, and thermodynamic parameters. Batch adsorption studies were carried out to evaluate the effect of pH, contact time, initial concentration (28–100 mg/g), adsorbent dose (0.05–0.3 g), and temperature (290–323 K) on the removal of BB3. The adsorption equilibrium data were analyzed by the Langmuir, Temkin, and Freundlich isotherm models, with the best fitting being the first one. The adsorption capacity (Qo) increased with increasing initial dye concentration, adsorbent dose, and temperature; the highest maximum Qo (59.53 mg/g) was obtained at 323 K. Pseudo‐first‐order and pseudo‐second‐order kinetic models and intraparticle diffusion models were used to analyze the kinetic data; good agreement between the experimental and calculated amounts of dye adsorbed at equilibrium were obtained for the pseudo‐second‐order kinetic models for the entire investigated concentrations domain. Various thermodynamic parameters, such as standard enthalpy of adsorption (ΔHo = 88.817 kJ/mol), standard entropy of adsorption (ΔSo = 0.307 kJ mol?1 K?1), and Gibbs free energy (ΔGo < 0, for all temperatures investigated), were evaluated and revealed that the adsorption process was endothermic and favorable. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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The photopolymerization of acrylate resins on wood surfaces suffers from retardation and inhibition effects due to the phenolic derivatives present at the interface. This article details the study of the effect of a set of phenolic compounds on the initiation step. The global effect was recorded by differential scanning calorimetry and photocalorimetry. A comparison between a direct photocleavable initiator such as 2,2‐dimethyloxy‐2‐phenylacetophenone (DMPA) and a two‐component system like benzophenone/N‐methyldiethanolamine (BP/MDEA) suggests that the retardation effect observed in the latter case is due to the interaction between phenols and the triplet state of BP. Subsequently, nanosecond transient absorption (NTA) spectroscopy was used to measure in acetonitrile the quenching rate constants kQ. A hydrogen abstraction occurred, and the ketyl radical quantum yield was also determined by NTA experiments. In comparison with the photoreduction mechanisms proposed in the literature, the high kQ values obtained were tentatively correlated to the half‐wave oxidation potentials of phenols in order to discuss the involvement of an electron transfer within the reaction. Some EPR experiments were done to confirm in situ the photoreduction process at the wood surface and the creation of phenoxyl radicals. The interaction of phenols with some initiating radicals was also studied. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2061–2074, 2000 相似文献
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The effect of the smectic and isotropic phase on the photo-polymerization of the chiral liquid crystalline 4-acryloxy-undecanyloxy-4′-[S(?)-2-methylbutyloxy]-biphenyl (monomer ( I )) was studied using FTIR. The effect of temperature on the birefringence of surface-oriented monomer ( I ) and its polymer obtained by in-situ photopolymerization was also investigated. The results show that photopolymerization in the isotropic phase proceeds at a higher rate than in the smectic phase, when monomer conversion is less than 60%; however, when monomer conversion is above 60%, the photopolymerization rate is independent of the initial phase state of monomer ( I ), and a highly oriented liquid crystalline polyacrylate film can be prepared by in-situ photopolymerization of the surface-oriented chiral acrylate ( I ). 相似文献
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Christophe Drevelle Sophie Duquesne Michel Le Bras Jrme Lefebvre Ren Delobel Andrea Castrovinci Carole Magniez Moïse Vouters 《应用聚合物科学杂志》2004,94(2):717-729
The thermal behavior of an acrylic binder resin used in back coatings for textile applications was studied. The influence of the crystalline form of the fire‐retardant additive on the thermal behavior was investigated. This resin formed a carbon char during its thermal degradation, so it may be assumed that it acts as a charring agent in intumescent systems with ammonium polyphosphate (APP) as the acid source. Thermogravimetric and spectroscopic analyses of acrylic binder resin/APP mixtures demonstrated the influence of the crystalline form of APP. The degradation mechanism of the binder resin could be described by ring closure and the formation of unsaturations. APP leads to the formation of a phosphocarbon structure that is thermally stable, whatever the crystalline form was of APP. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 717–729, 2004 相似文献
18.
The kinetics of the photopolymerization of epoxy acrylate/TiO2 nanocomposites, with 2′2‐dimethoxy‐1,2‐diphenylethan‐1‐one (Irgacure 651) or benzophenone/N‐methyl diethanolamine as photoinitiators, were studied by FTIR spectroscopy. It was found that nanocomposites had a decreasing photopolymerization rates in comparison with pure epoxy acrylate. The photopolymerization rate of the nanocomposite could also be influenced by initiator types, oxygen, film thickness, irradiation intensity, dispersing media of TiO2 slurry, and so forth. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3281–3287, 2006 相似文献
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Hybrid monomer, 4‐(1‐propenyl)oxybutyl acrylate, with cationic and free radical polymerizable group was synthesized. Real‐time Fourier transform infrared spectroscopy (FTIR) was used to monitor the photopolymerization kinetics of the monomer. Photopolymerization processing conditions, such as light intensity, photoinitiator concentrations have been evaluated. It was found that hybrid monomer showed higher efficiency of photopolymerization in comparison with the blend system. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献