Acrylonitrile System Research Articles

Terpolymerization of maleic anhydride, trans-stilbene and acrylic monomers

The results of radical terpolymerization of maleic anhydride (MA), trans-stilbene (Stb) and acrylic monomers ( n-butyl methacrylate (BMA) and acrylonitrile (AN)) as acceptor–donor–acceptor monomer systems are discussed. The structure and composition of terpolymers are determined by chemical (acid number for MA units) and elemental (content of N for AN units and O for BMA units) analyses, as well as by FTIR spectroscopy through recorded analytical absorption bands for MA (1770 and 1845 cm −1), Stb (864 cm −1) and BMA (1730 cm −1) units, respectively. The considerable change in the terpolymer compositions is observed when a strong acceptor MA is substituted with BMA (or AN), having comparatively low acceptor character in the system studied. Copolymerization constants for the MA ⋯ Stb complex and acrylic comonomers pairs are determined according to the modified Kelen–Tüdös equation. Obtained results show that at the chosen ratios of comonomers, radical terpolymerization proceeded mainly by a true “complex” mechanism in the stage of near binary copolymerization of MA ⋯ Stb complexed monomers with free BMA (or AN). The kinetics of terpolymerization and terpolymer compositions are studied in the low and high conversion stages. It is shown that for the MA–Stb–BMA system the dependence of R p on the concentration of individual comonomers has extreme character, while for BMA–Stb–AN this dependence does not have similar character. This fact indicated that terpolymerization in the BMA–Stb–AN system proceeds according to a classical statistical copolymerization mechanism. The terpolymer composition-thermal behaviour relationships are also studied by differential scanning calorimetry and thermogravimetric analysis methods.

Azeotropy in terpolymerization of N‐antipyryl acrylamide with different alkyl acrylates or styrene and acrylonitrile

AbstractTernary 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.

Factors influencing vapor‐phase photografting of styrene/acrylonitrile monomer mixtures on polymer films

AbstractAn accelerating effect due to a styrene (St)/acrylonitrile (AN) monomer mixture was investigated in vapor‐phase photografting on polymer films, on which a photoinitiator was coated. A maximum percent grafting was observed at a certain St concentration of monomer feed irrespective of the nature of photoinitiator, such as benzoyl peroxide, benzophenone, and α,α′‐azobisisobutylonitrile, and the type of polymer flim, such as low‐ and high‐density polyethylene, polypropyrene, and nylon 6. The same effect due to the monomer mixture was recorded for liquid‐phase photografting in a water‐ethanol mixture solvent. With photoinduced copolymerization of the St/AN mixture using benzoyl peroxide, conversion of AN was sharply reduced by the addition of St to the AN system using DMF, DMSO, methanol, and ethyl acetate solvents. In case of saturated hydrocarbon solvents such as n‐hexane, cyclohexane, n‐hexane, cyclohexane, n‐octane, and n‐decane, on the other hand, a maximum conversion was observed at a certain St concentration of monomer feed. The accelerating effect due to the St/AN mixture was discussed in terms of copolymerizability of monomers and a gel effect.

Polymerization of methacrylic acid and acrylonitrile by p‐nitrobenzyl triphenyl phosphonium ylide

AbstractRadical polymerization of methacrylic acid (MAA) and acrylonitrile (AN) in the presence of p‐nitrobenzyl triphenyl phosphonium ylide (p‐NBTPy) in dimethyl sulphoxide at 65 ± 0.1°C under inert atmosphere was investigated by dilatometry. The ylide failed to initiate the polymerization, but significantly accelerated the rate of polymerization. An interesting feature is that the average polymer molecular weight (M̄v) is a direct function of [p‐NBTPy]. The radical polymerization of MAA follows ideal kinetics since calculated monomer and initiator (AIBN) exponents are unity and 0.5, respectively. However, the AN system follows non‐ideal kinetics due primarily to radical termination and transfer reactions. The energy of activation, in the presence of p‐NBTPy, is low. The accelerating effect of p‐NBTPy has been attributed to decreased termination because the ylide did not affect the rate of decomposition of AIBN, as well as form a complex with monomer(s).

Organotin polymers. XII. Azeotropy in binary and ternary copolymerization reactions of di(tri‐n‐butyltin) itaconate with acrylic acid esters, styrene, and acrylonitrile

AbstractBinary and ternary copolymerizations of di(tri‐n‐butyltin) itaconate (TBTI) with methyl acrylate (MA), ethyl acrylate (EA), n‐butyl acrylate (BA), styrene (ST), and acrylonitrile (AN) were carried out in solution at 70°C in the presence of a free‐radical initiator. Experimental terpolymerization data agreed well with calculations based on the Alfrey–Goldfinger equation. The determination of unitary, binary, and ternary azeotropies of the various systems studied was easily handled by a computer. Ternary azeotropic compositions for TBTI–MA–AN and TBTI–EA–AN systems were 37 : 48 : 15 and 9 : 80 : 11 mol %, respectively. Also, “Pseudo‐azeotropic” regions were identified where the deviation between feed and polymer compositions is very small.

Alternating Copolymerization of Butadiene and Acrylic Compounds

A kinetic investigation on the alternating copolymerization of butadiene (BD) and methyl methacrylate (MMA) was undertaken by using EtAlCl2 (Al) and VOCl3 (V) as catalysts. The rate orders with respect to both components were the same as those for the butadiene (BD)–acrylonitrile (AN) system as reported previously; the rate of polymerization, Rp,o, is proportional to [Al]3/2 and [V]1/2, and the concentration of active species seems to be proportional to [Al]1/2 and [V]1/2.These relations are interpreted in terms of the mechanism involving a rapid initiation followed by stepwise propagation through a BD–MMA–Al complexed monomer. The formation of a benzene–MMA–Al complex as well as a MMA–Al complex is supposed. The rate order with respect to BD and acrylic monomer (A) was found to be complicated, i.e., in the BD–AN system Rp,o is proportional to [BD][AN]2, whereas in the BD–MMA system Rp,o depends on neither [BD] nor [MMA]. This fact may be accounted for in terms of the equilibrium of the BD–A–Al complex and the (A)n–Al complex. It is assumed that in a BD–AN–Al system the equilibrium constant for the (AN)n–Al complex is very large, whereas in a MMA–BD–Al system the equilibrium constant for the (MMA)n–Al complex is smaller than that of the BD–MMA–Al complex.

Photo and thermal polymerizations sensitized by donor–acceptor interaction. II. Photopolymerization and electronic spectroscopy of the isobutyl vinyl ether–acrylonitrile system

AbstractPhotopolymerization of acrylonitrile (AN), an acceptor monomer, was found to be accelerated in the presence of isobutyl vinyl ether (IBVE), a donor monomer. The propagation is completed by a radical mechanism as judged by copolymer compositions; in contrast to the N‐vinylcarbazole–AN system studied previously. This photopolymerization system is entirely stable if kept in the dark. The comparison of the relation between Rp and [IBVE]/[AN] ratio in the monomer feed found for the spontaneous photopolymerization with that for radical polymerization initiated by azobisisobutylonitrile in the dark leads to the conclusion that the rate of photoinitiation is enhanced by the interaction between AN and IBVE, whereas the propagation step by a radical mechanism is retarded by increasing concentration of IBVE. The contact charge‐transfer complex between IBVE and AN was confirmed by electronic spectroscopy of the polymerization system, which showed photosensitization by charge‐transfer interaction. The spectroscopic study of other weak donor–weak acceptor systems is also discussed.

Photo and thermal polymerization sensitized by donor–acceptor interaction. I. N‐vinyl‐carbazole–acrylonitrile and related systems

AbstractSpontaneous photo and thermal polymerization of N‐vinylcarbazole (VCZ)–acrylonitrile (AN), VCZ–acetonitrile, AN‐N‐ethylcarbazole, and AN‐ferrocene were studied. These combinations of electron donor with acceptor were thermally rather stable but showed prominent photopolymerizability when the systems were irradiated by near ultraviolet light. The VCZ–AN system showed multireactivity producing VCZ polymer and a copolymer of VCZ with AN. The composition of copolymer was approximately the same as that of polymer produced in radical copolymerization. The effects of additives (DPPH, NH3, H2O, air) indicated simultaneous occurrence of cationic and radical polymerization in the AN–VCZ and acetonitrile–VCZ systems. The results were interpreted on the assumption of initial formation of a cation radical–anion radical pair. The ratio of cationic to radical polymerization differed for photo and thermal polymerization. In no case was anionic polymerization detected.