Phase separation in random copolymers from high conversion free radical copolymerization, 1

A copolymer of vinylidene chloride and vinyl chloride containing 13.5% of the latter has been found to form completely miscible blends with atactic and isotactic poly(methyl methacrylate). poly(ethyl methacrylate), poly(n‐propyl methacrylate), and poly(cyclohexyl methacrylate). All but the latter of these blends were shown to exhibit lower critical solution temperature behavior at temperatures below that at which the copolymer rapidly degrades. The copolymer was found to be only partially miscible with poly(isopropyl methacrylate), while no detectable level of miscibility was observed with poly(methyl acrylate), poly(ethyl acrylate), poly(vinyl acetate), poly(vinyl methyl ether), or poly(vinyl methyl ketone). Information about interactions between components in the miscible blends was estimated from melting point data and is discussed.

Copolymers of various acrylic esters, from ethyl to octyl, with 5 to 15 per rent acrylonitrile or methacrylonitrile, were prepared by refluxing emulsion polymerization and in two instances by redox polymerization. These copolymers were easily vulcanized with sulfur and triethylene tetramine recipes. Heat-resistant vulcanizates were obtained from the copolymers of acrylonitrile with ethyl, butyl, amyl, and hexyl acrylates and also from the copolymer of methacrylonitrile with butyl acrylate. The octyl acrylate-acrylonitrile copolymers and the octyl acrylate, ethyl acrylate, and acrylonitrile terpolymerse did not show similar heat resistance. Terpolymers obtained from ethyl acrylate, butyl acrylate, and acrylonitrile, however, produced heat-resistant vulcanizates. The vulcanizates of lowest brittle points were obtained from copolymers of the higher acrylic esters, but regardless of the acrylic ester used, the brittle point was considerably increased with increasing acrylonitrile content of the copolymer. The copolymers from 95 per cent amyl acrylate—5 per cent acrylonitrile and the copolymer of 91 per cent hexyl acrylate—9 per cent acrylonitrile showed brittle points of −45° and −49° F, respectively. In general, the brittle point of heat-resistant stocks did not change by more than approximately 10° F on heat-aging for 72 hours at 350° F. The butyl acrylate-methacrylonitrile copolymer appeared to have somewhat better heat-aging properties than did the butyl acrylate-acrylonitrile copolymer.

Determination of selected fate and aquatic toxicity characteristics of acrylic acid and a series of acrylic esters

Photo-enforced stratification of liquid crystal / monomer mixtures : principle, theory and analysis of a paintable LCD concept

The association between ethanol and acrylic esters (methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate) in non-polar solvents, viz. n-hexane, carbon tetrachloride and benzene has been investigated by means of FTIR spectroscopy. The formation constants of 1:1 complexes have been calculated using Nash’s method. The values of the formation constant and the Gibbs energy vary with ester chain length, which suggests that the strengths of the intermolecular O–H···O=C bonds are dependent on alkyl group of the acrylic ester and the results show that the proton accepting ability of acrylic esters is in the order methyl methacrylate < ethyl methacrylate < butyl methacrylate and methyl acrylate < ethyl acrylate < butyl acrylate. The results also show a significant dependence of the association constant upon the solvents used. The solvent effect on the hydrogen bond equilibria is discussed in terms of specific interaction between the solute and solvent.

Potentiation of acrylate ester toxicity by prior treatment with the carboxylesterase inhibitor triorthotolyl phosphate (TOTP)

Ternary copolymerization of N‐antipyryl acrylamide (NAA) with different alkyl acrylates [methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BuA)] or styrene (ST) and acrylonitrile (AN) were carried out in solution at 65°C in the presence of AIBN as a free radical initiator. Experimental terpolymerization daca agree well with calculations based on the Alfrey–Goldfinger equation. The determination of unitary, binary, and ternary azeotropes of various systems studied was easily handled by a computer program. Ternary azeotropic compositions for NAA–MA–AN, NAA–EA–AN, NAA–BuA–AN, and NAA–ST–AN system were 31.0 : 10.0 : 59.0, 37.0 : 09.0 : 54.0, 23.0 : 10.0 : 67.0, and 66.5 : 30.50 : 03.0 mol %, respectively. Selective unitary and binary azeotropic compositions were polymerized and the obtained results show good agreement between the theoretical and experimental terpolymer composition for each case. Also, pseudo‐azeotropic regions were identified where the deviation between feed and polymer composition is very small. The azeotropic points of the four systems were confirmed using Tarasov et al.'s equations and were found to have satisfactory results. © 1994 John Wiley & Sons, Inc.

Ultrasonic velocities of binary liquid mixtures of methyl acrylate, ethyl acrylate, butyl acrylate and methyl methacrylate with decane-1-ol have been measured at 303.15 and 313.15 K and at atmospheric pressure. Experimentally measured ultrasonic velocities were correlated using Jouyban-Acree model. Deviations in isentropic compressibility were calculated using ultrasonic velocity and have been fitted to Redlich-Kister polynomial equation. Ultrasonic velocities were also calculated theoretically using Nomoto, Van Dael (VAN), free length theory (FLT) and collision factor theory (CFT).Different derived thermodynamic parameters like excess specific acoustic impendence, excess available volume, excess intrinsic pressure andmolar sound velocity were also calculated. Graphical representations of these excess derived thermodynamic parameters used to explain typeand extent of intermolecular interactions in these binary systems. Ultrasonic velocity measurement of liquid mixtures of non electrolytes provides an excellent tool to investigate inter and intramolecular interactions between like and unlike molecules. This study is a powerful means of characterizing various aspects of physicochemical behaviors of liquid mixtures and molecular interactions.

Study on grafting of different types of acrylic monomers onto natural rubber by γ-rays

Problems in the current experimental determination of radical reactivity ratios (i.e., 's values') in free-radical copolymerization and the resulting limited physical meaning of these reactivity ratios are highlighted in the present work. It is exemplified that the radical reactivity ratios obtained via fitting of average propagation rate coefficients are very sensitive to small uncertainties in monomer reactivity ratios and homopropagation rate coefficients. Furthermore, the failure to select an appropriate modelling method, and to design experiments so as to satisfy its assumptions, may lead to incorrect parameter estimates. These problems result in large uncertainties in the measured values of the radical reactivity ratios, which in turn lead to large uncertainties in calculated ratios of propagating radical concentrations. This suggests that experimental determinations of the relative radical concentrations may lead to complimentary means for obtaining information on radical reactivity ratios, and possible ways of obtaining this information through catalytic chain transfer experiments are discussed.

In an attempt to compare relative reactivities of vinyl monomers toward grafting, methyl methacrylate (MMA) and acrylic acid (AAc) were grafted separately to Himachali wool in aqueous medium by using ceric ammonium nitrate (CAN) as redox initiator. Nitric acid was found to catalyze the reaction. Percent grafting was determined as a function of concentration of nitric acid, concentration of CAN, concentration of monomer, time, and temperature. Optimum conditions for maximum grafting were evaluated for each monomer and were found to depend upon the nature of the monomer. Reactivities of MMA and AAc toward grafting were compared with those of methyl acrylate (MA), ethyl acrylate (EA), and vinyl acetate (VAc) reported earlier from this laboratory and were found to follow the order MA > EA > MMA > VAc > AAc. An explanation for the observed order of reactivity of different vinyl monomers is presented.

Mixtures of gelatin and maltodextrin in aqueous solution have been quenched to temperatures at which they are initially miscible but where gelatin ordering is initiated. In many cases phase separation was observed to occur after a significant time delay, and the dependence of these delays on quench temperature and biopolymer concentration has been studied in detail using turbidity measurements and confocal laser scanning microscopy (CLSM). Furthermore, by observing the optical rotation (OR) and turbidity of the system simultaneously, the gelatin helix content and the time delay before the onset of phase separation were monitored concurrently. The observed delay times were found to correspond to the time taken for the development of a certain degree of gelatin ordering, which drives the separation process. A further consequence of gelatin ordering is the viscosifying of the solution and, at sufficient concentrations, the formation of a gel. Therefore, rheological measurements have been used in addition to turbidity measurements and CLSM in order to monitor further the structural development of the systems. A comparison of the data obtained from these techniques shows that while the development of a certain elasticity will trap the system morphology, this elasticity is not directly related to that found at the gel point. At low maltodextrin concentrations, where phase separation was not detected by turbidity, transmission electron microscopy (TEM) has been used to examine the microstructure on a smaller length scale.

Temperature propagation in a near-critical fluid sample (${\mathrm{SF}}_{6}$) is experimentally studied under reduced gravity in space. Onset of phase separation is indicated by the appearance of a spinodal scattering ring. Critical speeding up of temperature equilibration prior to phase separation and markedly slowed-down temperature equilibration during phase separation are observed.

The phase separation of different in‐situ semi‐1 interpenetrating polymer networks (IPNs) based on polyurethane and polystyrene has been followed by light transmission. The effect of the presence ab initio of small amounts of homopolystyrene in the initial reaction mixture on the phase separation process has also been examined. If gelation of the polyurethane occurs before the onset of phase separation, the latter is impeded or strongly limited, and transparent semi‐1 IPNs are obtained. In the opposite case, phase separation is macroscopic and the material is turbid.

The supply of acrylic esters is expected to continue to be tight, concludes a recent report by Eldib Engineering & Research Inc., a chemical market research firm located in Berkeley Heights, N.J. Acrylic esters include n -butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, and methyl acrylate. U.S. supply has been tight for a couple of years, says Paul Gierer of Eldib, because production has not met the growing demands of major end-use markets. Tight supply of acrylic acid feedstock is also a contributing factor. With the current very high capacity use for acrylic esters, Gierer says, the situation is not expected to improve until capacity additions by the major producers are brought on line in the next year or two. According to SRI International, as of January 1990, producers of acrylic esters are BASF, Union Carbide, Hoechst Celanese, and Rohm & Haas, with a total industry capacity of 1.46 billion lb. Significant ...