Behavior In Different Solvents Research Articles

Interpenetrating polymer networks with controllable intermolecular hydrogen bonding: Swelling behavior

The swelling behavior in different solvents of IPNs based on poly(butyl acrylate) and modified polystyrene containing strong proton-donor hydroxyl groups is studied. The experimental data of the volume fractions of the networks in the swollen state Vexpt at equilibrium are compared with those expected from the Thiele-Cohen equation (VTC), which assumes that the two networks are independent and no additional crosslinks form during the formation of the IPNs. For the IPNs without inter-component hydrogen bonding, Vexpt in toluene are in good agreement with VTC. As the hydroxyl content increases, the deviation of Vexpt from VTC increases indicating more crosslinks form in the process of IPN formation. This deviation in the solvents of proton-acceptor type becomes smaller but still apparent. This result implies that hydrogen bonding between the components is destroyed by the solvents but the physical entanglements formed during the formation of the IPNs remain.

Synthesis of a novel polyesterimide

AbstractA new polyesterimide has been synthesized from trimellitic acid anhydride, diaminodiphenylsulfone, and bisphenol‐A following three different routes. Solubility behavior in different solvents, solution viscosity, density, crystallinity, and thermal and electrical properties of the polyesterimide have been discussed. Results indicate that the polyesterimide thus prepared has medium thermal stability.

Copolymers of 2‐hydroxyethyl methacrylate and alkyl methacrylates. I. Synthesis and characterization

AbstractCopolymerization of 2‐hydroxyethyl methacrylate (HEMA) with ethyl methacrylate (EMA) and n‐butyl methacrylate (BMA) was carried out in bulk at 70°C ± 1°C using 0.2% benzoyl peroxide as initiator in nitrogen atmosphere. Number average molecular weight (Mn) of the copolymers was determined by dynamic osmometry. Intrinsic viscosity [η] of HEMA‐BMA copolymers was evaluated at 35°C in dimethyl formamide. These copolymers were also characterized by infrared spectroscopy and density measurements. Cohesive energy densities (CED) of these polymers were determined by observing their swelling behavior in different solvents. It was found that a decrease in alkyl methacrylate content resulted in an increase in the CED values of the copolymers.

Comparisons of styrene ionomers prepared by sulfonating polystyrene and copolymerizing styrene with styrene sulfonate

AbstractAs part of a continuing study of ion‐containing polymers, a comparison has been made on styrene‐based sulfonate ionomers obtained by two different processes. Copolymers of styrene with sodium styrene sulfonate (SSS) have been compared with corresponding polymers obtained by the sulfonation/neutralization of preformed polystyrene (S–PS). The former system covered a range of sulfonate level from 1 to 30 mol %, while the latter ranged from about 1 to 7 mol %. The characterization of these materials has been conducted using solubility behavior, dilute solution viscometry, thermal mechanical analysis, density measurements, and water adsorption studies. At low (ca. 1%) levels the solubility behavior of the SSS copolymers and the sulfonated polystyrenes were similar. However, at higher sulfonate levels the solubility behavior in different solvents and the dilute solution viscometry were significantly different for the two systems. Similarly, thermal analysis studies (DSC) showed that the glass transition of the sulfonated polystyrene increased linearly with sulfonate level, while the Tg for the SSS copolymer increased modestly, up to about 7 mol % sulfonate content, and then remained constant. Significant differences in the softening behavior and water absorption characteristics were also observed for these two classes of ionomers. Although molecular weights and molecular weight distributions are not now available for these ionomers, the differences in their behavior does not appear to be due simply to differences in molecular weight. It is postulated that the differences in the copolymer and the S–PS ionomers may originate with differences in sulfonate distribution. It is suggested that the SSS monomer units are incorporated as blocks in the copolymer as opposed to a more random distribution in the S–PS ionomer. Indirect evidence in support of his argument is found, for example, in the case of the copolymer in the solubility behavior, the relative independence of Tg on sulfonate concentration and the apparent existence of a second, high temperature transition tentatively attributable to an ion‐rich phase. Additional studies are required to confirm this hypothesis.

Synthesis and physicochemical studies of some new amphoteric ion exchangers

AbstractSome new amphoteric ion exchangers have been synthesized by condensing salicylic acid, p‐hydroxybenzoic acid, sulfosalicylic acid, gallic acid, 3‐hydroxy‐2‐naphthoic acid, β‐resorcylic acid, and resacetophenone with epichlorohydrin employing ethylenediamine as a crosslinking agent. Some of the physicochemical properties, such as moisture content, true density, apparent density, void volume fraction, concentration of ionogenic groups, exchange capacity, rate of exchange, pH‐titration curves, pK values, isoionic point, thermal stability, oxidation resistance, and swelling behavior in different solvents, have been investigated.