J. Varga

INVESTIGATIONS IN THE FIELD OF RADIATION-INDUCED SOLID-STATE POLYMERIZATION. XIII. INHIBITION OF THE SOLID-STATE POLYMERIZATION

Abstract The solid system of n -vinylsuccinimide with benzoquinone is characterized by the formation of an eutectic. Up to the composition of the eutectic, the rate of the solid-state polymerization decreases regularly with an increase in the BQ concentration. Beyond the eutectic composition the polymerization rate is constant even at very high concentrations of benzoquinone. This is explained by the development of a system (as shown by the X-ray patterns) with maximum heterogeneous interfaces and of a very fine structure in which the inhibitor interfaces and the inhibitor molecules are able to exert their inhibiting action on the surfaces of the monomer crystals. The phase diagram of the n -vinylsuccinimide -phthalic anhydride system shows a eutectic also. In this case, polymerization rate increases with increasing phthalic anhydride concentration, and no energy transfer effect can be observed in the heterogeneous system containing an aromatic component.

Investigations in the field of radiation-induced solid state polymerization- VII. The influence of preformed polymer on the kinetics of the solid state polymerization

Abstract A study has been made of the influence upon the kinetics of the solid-state polymerization of N-vinyl succinic imide by the quantity of polymer present in the monomer-polymer mixtures; the pre-formed polymer was produced by radiation-induced solid-state polymerization. The pre-formed polymer produces a great acceleration. The phenomenon may result from deformations in the crystal-matrix and the resulting greater mobility of the monomer molecules. The effect is expected to occur for all those monomers for which acceleration is observed during the course of solid-state polymerization. On the other hand, pre-formed polymer should retard the solid-state polymerization of those monomers for which there is a slowing down during the course of solid-state polymerization.

Thermal and optical studies on hexa-2,4-diyne-1,6-diyl-bis(4-n-hexoxybenzoate)

Abstract As part of a programme investigating mesogenic diacetylenes a symmetrically disubstituted diacetylene has been synthesized and polymerized. Thermal, thermo-optical and IR studies have been carried out to investigate the different crystalline forms of the diacetylene.

Investigations in the field of radiation-induced solid state polymerization-XXXI

Binary systems of N-vinyl succinimide and endomethylene tetrahydrophtalic acid monoallyl ester with some additives were studied. It was established that the amount and nature of the quasi-eutectic structure could be regulated to the desired extent only when crystallization was performed under nearly isothermal conditions. In the present conditions for heat transfer, one component of the binary system should have a maximum linear crystallization rate low enough to produce a maximum linear crystallization rate of the quasi-eutectic structure less than 1 × 10−2 mm/sec. In many cases, kinetic results could definitely be connected with qualitative and quantitative changes in the quasi-eutectic structure. Some phenomena suggested the roles of certain structural features and the phase conditions of the ternary system formed by the polymer produced.Binary systems of N-vinyl succinimide and endomethylene tetrahydrophtalic acid monoallyl ester with some additives were studied. It was established that the amount and nature of the quasi-eutectic structure could be regulated to the desired extent only when crystallization was performed under nearly isothermal conditions. In the present conditions for heat transfer, one component of the binary system should have a maximum linear crystallization rate low enough to produce a maximum linear crystallization rate of the quasi-eutectic structure less than 1 × 10−2 mm/sec. In many cases, kinetic results could definitely be connected with qualitative and quantitative changes in the quasi-eutectic structure. Some phenomena suggested the roles of certain structural features and the phase conditions of the ternary system formed by the polymer produced.

INVESTIGATIONS IN THE FIELD OF RADIATION-INDUCED SOLID-STATE POLYMERIZATION. XXI. THE INFLUENCE OF THE CONDITIONS OF CRYSTALLIZATION ON THE SOLID-PHASE POLYMERIZATION OF BINARY EUTECTIC SYSTEMS.

Abstract A study has been made of the phase diagrams of the systems (N-vinyl succinimide—endo methylene tetrahydro phthalic acid mono allyl ester), (succinimide—endo methylene tetrahydro phthalic acid mono allyl ester) and (acetanilide—endo methylene tetrahydro phthalic acid mono allyl ester). It has been concluded that a quasi-eutectic range of co-crystallization can be observed, depending on the conditions of undercooling and those of nucleation. It has been shown, for the case of N-vinyl succinimide—endo methylene tertahydro phthalic acid mono allyl ester, that the rate of solid phase polymerization changes directly with the proportion of the eutectic. It has been ascertained that, in binary systems, the proportion of the eutectic structure and consequently the observed rate of polymerization are markedly influenced by the tendency of the system to undercooling and by the nucleation during the crystallization.