Acrylics, determination Carboxyl groups

Determining the amount of surface carboxyl groups as a function of the surfactant, it was shown that the dense monolayer of carboxylic groups (0.68nm2 per COOH 1.47 groups per nm2) on the particles prepared with nonionic surfactant was almost achieved with 3wt% of acrylic acid. More than 10 wt% of acrylic acid was required in the case of SDS-stabilized particles. TEM images of carboxyl-functionalized polystyrene particles stabilized with nonionic (Lutensol AT50) and ionic (SDS) surfactant are presented in Fig. 8. 

Divalent Effect In the brine of low to medium sahnities (monovalent content), the viscosity of polyacrylamide solution increases as hydrolysis proceeds (increases). However, in the presence of divalents, the viscosity behavior will be determined largely by the divalent metal ion concentrations. As hydrolysis increases, more acrylic acid exists in the solution. Hydrolyzed polyacrylamides (negative carboxyl groups) interact strongly with divalent metal cations such as Csi and Mg ". This phenomenon is commonly associated with reduction in solution viscosity, formation of gels or precipitates. 

Functionality. The number of carboxyl equivalents was determined from the potentlometrlc acid-base titration. The number molecular weight iii of the CTPnBA was determined by the Vapor Pressure Osmometer measurement. The product of the number of acid equivalents by the molecular weight divided by the weight of the titrated PnBA sample is the calculated average number of carboxyl groups per chain of the poly n-butyl acrylate. 

Many investigators have studied polymer surfaces for years [74,75] and have been successful in determining combinations of two or more valence states [76,77] by the mathematical process of deconvoluting the peak assignments [78]. It was only recently that latexes were examined by ESCA. Davies et al. [79] prepared a series of homopolymers of poly(methyl methacrylate) (PMMA) and poly(butyl methacrylate) (PBMA), and also poly[(methyl methacrylate)-co-(butyl methacrylate)] (PMMA-PBMA), by surfactant-free emulsion polymerization. It was found that the surface of the latex film was rich in PMMA, which may possibly be explained by the reactivity ratios for the MMA/BMA system (ri = 0.52 and rj = 2.11) [80], Recently, Arora et al. carried out angle-dependent ESCA studies on a series of films prepared from core-shell ionomeric latexes (with a polystyrene core and a styrene/n-butyl acrylate/ methacrylic acid copolymer shell) to determine the distribution of carboxyl groups in the films [81,82]. 

Most methods for the determination of carboxyl groups in polymers are based on titration techniques including, for example, the following copolymers acrylic acid-itaconic acid [16], acrylic acid-ethyl acrylate [17] and maleic acid-styrene [18]. High-frequency titration has been applied [19] to the analysis of itaconic acid-styrene and maleic acid-styrene copolymers. The method can also be used to detect traces of acidic impurities in polymers, and in the identification of mixtures of similar acidic copolymers. Titration indicates that the acid segments in the copolymers of itaconic acid-styrene, and maleic acid-styrene, and the homopolymer polyitaconic acid, act as dibasic acids. The method has a sensitivity that permits identification and approximate resolution of two carboxylate species in the same polymer, for example ... 

Most methods for the determination of carboxyl groups in polymers are based on titration techniques. The following copolymers, acrylic acid-itaconic acid," acrylic acid-... 

A new type of copolymer resist named ESCAP (environmentally stable chemical amplification photoresist) has recently been reported from IBM [163], which is based on a random copolymer of 4-hydroxystyrene with tert-butyl acrylate (TBA) (Fig. 37), which is converted to a copolymer of the hydroxystyrene with acrylic acid through photochemically-induced acid-catalyzed deprotection. The copolymer can be readily synthesized by direct radical copolymerization of 4-hydroxystyrene with tert-butyl acrylate or alternatively by radical copolymerization of 4-acetoxystyrene with the acrylate followed by selective hydrolysis of the acetate group with ammonium hydroxide. The copolymerization behavior as a function of conversion has been simulated for the both systems based on experimentally determined monomer reactivity ratios (Table 1) [164]. In comparison with the above-mentioned partially protected PHOST systems, this copolymer does not undergo thermal deprotection up to 180 °C. Furthermore, as mentioned earlier, the conversion of the terf-butyl ester to carboxylic acid provides an extremely fast dissolution rate in the exposed regions and a large... 

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