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由丙烯酸(AA)、α-甲基丙烯酸(MAA)和丙烯酰胺(AM)合成了具有很好DH敏感性和一定温度敏感性的智能水凝胶,考察了合成温度、丙烯酰胺、交联剂和引发剂用量对制备的水凝胶溶胀性能的影响。结果表明,在60℃下,单体从和MAA用量分别为100mmol和75mmol时,单体AM、交联剂和引发剂用量分别为反应物总质量的32.8%、0.2%和0.4%时,制备的水凝胶溶胀性能最好。考察了介质的离子浓度、pH值和温度对水凝胶溶胀比的影响,结果表明,离子浓度越大,水凝胶的溶胀比越小;水凝胶具有一定的DH可逆性。 相似文献
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党娟华 《精细石油化工进展》2006,7(3):33-34,41
以水为溶剂,马来酸酐(MA)、丙烯酸(AA)为单体,过硫酸盐-次磷酸盐氧化还原体系为引发剂,合成马来酸酐-丙烯酸含膦共聚物阻垢剂。研究了聚合条件对共聚物阻垢性能的影响,确定最佳聚合条件为:马来酸酐与丙烯酸摩尔比1:3,次磷酸盐用量为单体总质量的20%,引发剂用量为单体总质量的10%,反应温度90℃,反应时间4h。在此反应条件下合成的聚合物对CaCO3和CaSO4有较好的阻垢性能。 相似文献
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Zbigniew Czech 《应用聚合物科学杂志》2003,87(8):1354-1357
This article shows the influence of some chain‐transfer agents as inhibitors for acrylic solvent‐based polymerization. These chain‐transfer agents can offer significant advantages, as outlined below. The following chain‐transfer agents were studied to stop or slow down the polymerization process in the case of a runaway: n‐dodecyl mercaptan, trimethylolpropane‐trimercaptoacetate, phenothiazine, diphenylphenylen diamine, cuprum oxide, isopropanol, toluene, and carbon tetrachloride. Synthesized pressure‐sensitive adhesive based on acrylic polymers and containing 2‐ethylhexyl acrylate, methyl acrylate, and acrylic acid were used for the production of self‐adhesives with high cohesion. The polymerization was accomplished in ethyl acetate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1354–1357, 2003 相似文献
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Recent developments in rubber-toughened structural acrylic adhesives now offer sheet steel fabricators the opportunity to replace conventional metal fastening techniques such as spot welding with lower cost, durable, more versatile structural adhesive bonding. These developments, in particular much improved ability to bond oily/waxy surfaces common to the motor car industry and improved retention of fracture toughness after exposure to paint stoving temperatures, are discussed in this paper. 相似文献
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TeMxMo1.7O mixed oxides (M = V and/or Nb; x = 0-1.7) have been prepared by calcination of the corresponding salts at 600 °C in an atmosphere of N2. A new crystalline phase, with a Te/V/Mo atomic ratio of 1/0.2-1.5/1.7, has been isolated and characterised by XRD and IR spectroscopy. This phase is observed in the TeVMo or TeVNbMo mixed oxide but not in the TeNbMo mixed oxide. The new crystalline phase shows an XRD pattern similar to Sb4Mo10O31 and probably corresponds to the M1 phase recently proposed by Aouine et al. (Chem. Commun. 1180, 2001) to be present in the active and selective MoVTeNbO catalysts. Although these catalysts present a very low activity in the propane oxidation, they are active and selective in the oxidation of propene to acrolein and/or acrylic acid. However, the product distribution depends on the catalyst composition. Acrolein or acrylic acid can be selectively obtained from propene on Nb-free or Nb-containing TeVMo catalysts, respectively. The presence of both V and Nb, in addition to Mo and Te, appears to be important in the formation of acrylic acid from propene. 相似文献
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Osmotic pressure measurements were satisfactorily used to compute the effective charge of poly(acrylic) acid (PAA) at different pHs and with different monovalent and divalent counterions. This experimental method is sensitive to the osmotically active species (polymer and counterions). After correction for the polymer contribution to the total osmotic pressure (solvency and excluded volume), the remaining pressure can be attributed to the polyelectrolyte counterions and processed with Donnan and equation of state in order to compute the effective charge number per polymeric chain (Zeff). The behavior of Zeff against the chain concentration and pH was investigated after neutralization of PAA with LiOH, NaOH, and TMAOH. The results clearly indicate that the nature of the monovalent counterion has no effect on Zeff leading to the conclusion that the interaction between monovalent counterions and the acrylate functionality is purely electrostatic in agreement with conductimetric and potentiometric results reported in the literature. The behavior of Zeff against the degree of ionization of the polymer and its concentration is also in good agreement with the theoretical expectations of the theory of ionic condensation. Osmotic measurements were also used in order to understand the influence of divalent cations (Mg2+, Ca2+, Ba2+) on Zeff of the sodium salt of PAA at pH 9 and at different divalent/acrylate molar ratio. All the divalent cations depress Zeff each of one at different degrees, confirming a specific divalent/polymer interaction. The energy of hydration of cations can explain most of the observed results with divalents. 相似文献