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Radiation Polymerization in the Solid Phase; Polymerisation radiochimique en phase solide; Radiatsionnaya polimerizatsiya v tverdoj faze; Radiopolimerizacion en fase solida

Conference:

Abstract

The radiation polymerization of solid and frozen monomers has recently attracted a great deal of attention because of its theoretical and practical importance in chemical kinetics and radiation chemistry. The strict spacing of monomer units in a polymer brings about a sharp improvement in the physico-chemical properties without any change of chemicai composition. In the synthesis of stereo-regular polymers, the matrix principle is used, i.e. the monomer unit is strictly oriented spatially by the formation of a complex with a catalyst or some other compound. In the radiation polymerization of a number of monomers oriented in clathrate complexes of urea and thio-urea, for instance, crystal stereo-regular polymers were obtained. The simplest variation, however, is the orientation of a monomer in its own crystal lattice. Although many of the theoretical questions involved remain obscure, the technique is extremely promising. Thus, highly crystalline polyoxymethylene has already been obtained by the radiation polymerization of crystalline trioxane. Nevertheless, a more detailed theoretical investigation of the technique is required. For each separate monomer, the contribution to the general picture made by the different types of reaction taking place during irradiation and the subsequent fusion of the solid monomers (specific radiation reaction, post-polymerization and polymerization at  More>>
Publication Date:
Nov 15, 1963
Product Type:
Conference
Resource Relation:
Conference: Conference on the Application of Large Radiation Sources in Industry, Salzburg (Austria), 27-31 May 1963; Other Information: 17 figs., 34 refs.; Related Information: In: Industrial Use of Large Radiation Sources. Proceedings of a Conference on the Application of Large Radiation Sources in Industry. V. I| 436 p.
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 07 ISOTOPES AND RADIATION SOURCES; ACRYLONITRILE; ACTIVATION ENERGY; CHEMICAL PROPERTIES; CRYSTAL LATTICES; CRYSTALS; ELECTRON SPIN RESONANCE; EXCITED STATES; IRRADIATION; KINETICS; LIQUIDS; MONOMERS; PHASE TRANSFORMATIONS; POLYMERIZATION; POLYMERS; SOLIDS; SYNTHESIS; UREA
OSTI ID:
22100756
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13R0333058804
Submitting Site:
INIS
Size:
page(s) 193-217
Announcement Date:
Jun 06, 2013

Conference:

Citation Formats

Barkalov, I. M., Gol'danskij, V. I., Enikolopov, N. S., Terekhova, S. F., and Trofimova, G. M. Radiation Polymerization in the Solid Phase; Polymerisation radiochimique en phase solide; Radiatsionnaya polimerizatsiya v tverdoj faze; Radiopolimerizacion en fase solida. IAEA: N. p., 1963. Web.
Barkalov, I. M., Gol'danskij, V. I., Enikolopov, N. S., Terekhova, S. F., & Trofimova, G. M. Radiation Polymerization in the Solid Phase; Polymerisation radiochimique en phase solide; Radiatsionnaya polimerizatsiya v tverdoj faze; Radiopolimerizacion en fase solida. IAEA.
Barkalov, I. M., Gol'danskij, V. I., Enikolopov, N. S., Terekhova, S. F., and Trofimova, G. M. 1963. "Radiation Polymerization in the Solid Phase; Polymerisation radiochimique en phase solide; Radiatsionnaya polimerizatsiya v tverdoj faze; Radiopolimerizacion en fase solida." IAEA.
@misc{etde_22100756,
title = {Radiation Polymerization in the Solid Phase; Polymerisation radiochimique en phase solide; Radiatsionnaya polimerizatsiya v tverdoj faze; Radiopolimerizacion en fase solida}
author = {Barkalov, I. M., Gol'danskij, V. I., Enikolopov, N. S., Terekhova, S. F., and Trofimova, G. M.}
abstractNote = {The radiation polymerization of solid and frozen monomers has recently attracted a great deal of attention because of its theoretical and practical importance in chemical kinetics and radiation chemistry. The strict spacing of monomer units in a polymer brings about a sharp improvement in the physico-chemical properties without any change of chemicai composition. In the synthesis of stereo-regular polymers, the matrix principle is used, i.e. the monomer unit is strictly oriented spatially by the formation of a complex with a catalyst or some other compound. In the radiation polymerization of a number of monomers oriented in clathrate complexes of urea and thio-urea, for instance, crystal stereo-regular polymers were obtained. The simplest variation, however, is the orientation of a monomer in its own crystal lattice. Although many of the theoretical questions involved remain obscure, the technique is extremely promising. Thus, highly crystalline polyoxymethylene has already been obtained by the radiation polymerization of crystalline trioxane. Nevertheless, a more detailed theoretical investigation of the technique is required. For each separate monomer, the contribution to the general picture made by the different types of reaction taking place during irradiation and the subsequent fusion of the solid monomers (specific radiation reaction, post-polymerization and polymerization at phase transition points) needs clarification. Recent detailed research at the Institute of Chemical Physics, USSR, into the solid-phase radiation-polymerization kinetics of a number of monomers, using the calorimetric method and an EPR signal, has revealed the essential role of the specific radiation reaction during the irradiation. The polymerization process for acrylonitrile (from -196{sup o}C to -140{sup o}C) and vinyl acetate (-196{sup o}C to -100{sup o}C) ceases when irradiation is discontinued despite the retention of the shape and intensity of the EPR signal and despite the long lifetime of the irradiationproduced ions. The results of these experiments indicate the potentially considerable role of short-lived excited states in the radiation solid-phase polymerization of a number of monomers. Such ''under-beam'' polymerization occurs in practice without activation energy, unlike slow post-polymerization, which occurs with the same activation energy as does the liquid phase process. (author) [French] La polymerisation radiochimique des monomeres a l'etat solide et congele fait l'objet depuis quelque temps d'une attention soutenue. Cette question presente un grand interet tant du point de vue pratique qu'en ce qui concerne les theories modernes de la cinetique chimique et de la radiochimie. On sait qu'une configuration speciale strictement ordonnee des unites monomeriques dans le polymere provoque une amelioration sensible des proprietes physico-mecaniques sans que la composition chimique s'en trouve alteree. Pour realiser la synthese de polymeres a structure spatiale reguliere, on fait appel au principe de la matrice; en d'autres termes, l'unite monomerique est nettement orientee dans l'espace par la formation d'un complexe a l'aide d'un catalyseur ou de toute autre substance appropriee. Ainsi, lors de la polymerisation radiochimique de plusieurs monomeres orientes dans des clathrates de l'uree ou de la thio-uree, on a obtenu des polymeres cristallins a structure spatiale reguliere. Cependant, l e procede le plus simple consiste a orienter le monomere dans son propre reseau cristallin. Bien que de nombreuses questions theoriques soient encore a elucider dans ce domaine, l'application de la methode mentionee est fort seduisante. Ainsi, la polymerisation radiochimique du trioxyethylene cristallise a deja permis d'obtenir un polyoxymethylene fortement cristallise. Cependant, cette methode necessite une etude theorique plus approfondie. Pour chaque monomere, il est indispensable de determiner dans quelle mesure les divers types de reactions qui s'operent lors de l'irradiation et de la fusion consecutive des monomeres solides (reaction radiochimique specifique, post-polymerisation et polymerisation aux points de transition d'une phase a l'autre) contribuent a l'ensemble du processus. Les travaux approfondis sur la cinetique de la polymerisation radiochimique qui ont ete faits recemment par la methode calorimetrique et l'observation du signal RPE a l'Institut de physique chimique ont montre qu'un role essentiel incombe a la reaction radiochimique specifique qui s'opere durant l'irradiation. Des que l'irradiation est interrompue, le processus de polymerisation de l'acrilonitryle (entre-196 et -140{sup o}C) et de l'acetate de vinyle (entre-196 et -100{sup o}C) s'arrete bien que le signal RPE conserve sa forme et son intensite et que les ions crees sous l'action des rayonnements aient une duree de vie prolongee. Les resultats de ces experiences laissent supposer que les etats d'oxydation de courte duree peuvent jouer un role important dans l a polymerisation radiochimique de certains monomeres en phase solide. Une telle polymerisation ''sous le faisceau'' s'opere pratiquement sans aucune energie d'activation contrairement a la polymerisation lente qui se fait avec la meme energie d'activation que le processus en phase liquide. (author) [Spanish] Ultimamente se viene concediendo gran atencion a la radiopolimerizacion de monomeros solidos y ''congelados''. Este problema revista interes practico y teorico por lo que respecta a las nuevas teorias de la cinetica quimica y la radioquimica. Commo se sabe, una configuracion espacial estrictamente ordenada de las unidades monomericas en un polimero mejora de manera considerable sus propiedades fisico-mecanicas sin alterar su composicion quimica. Para la sintesis de los polimeros de estructura espacial regular, se aplica el principio de la matriz, es decir que se orienta netamente en el espacio la unidad monomerica por medio de la formacion de un complejo con ayuda de un catalizador u otra sustancia adecuada. Por ejemplo, en la radiopolimerizacion de una serie de monomeros orientados en complejos clatraticos de urea y tiourea, se obtienen polimeros cristalinos de estructura espacial regular. Sin embargo, el procedimiento mas sencillo consiste en orientar el monomero en el propio reticulado cristalino. Aunque todavia quedan por dilucidar numerosos aspectos teoricos de esta cuestion, la aplicacion practica del metodo parece sumamente promisoria. Asi, en la radiopolimerizacion del trioxietileno cristalino, se obtiene un polioximetileno altamente cristalizado. Con todo, es necesario proseguir el estudio teorico de esta cuestion. Para cada monomero resulta indispensable determinar en que medida los distintos tipos de reacciones que se desarrollan durante la irradiacion y la fusion consecutiva de los monomeros solidos (reaccion radioquimica especifica, postpolimerizacion y polimerizacion en los puntos de transicion de las fases) contribuyen al conjunto del proceso. El estudio detallado de la radiopolimerizacion de una serie de monomeros, mediante el metodo calorimetrico y la observacion de la resonancia paramagnetica de los electrones llevada a cabo recientemente en el Instituto de fisicoquimica de Moscu, ha demostrado que la reaccion radioquimica especifica desempefia el papel fundamental en el curso de la irradiacion. Una vez concluida esta, los procesos de polimerizacion del acrilnitrilo (entre -196{sup o}C y -140{sup o}C) y del acetato de vinilo (entre -196{sup o}C y -100{sup o}C) se detienen por mas que las senales de resonancia paramagnetica de los electrones conserven la misma forma e intensidad u por prolongada que sea la duracion de los iones generados por la irradiacion. Los resultados de estos experimentos atestiguan la probable importancia del papel que desempenan los estados excitados de breve duracion en la radiopolimerizacion de una serie de monomeros en fase solida. Esa polimerizacion ''bajo el haz'' se desarrolla practicamente sin energfa de activacion, a diferencia de la postpolimerizacion lenta, que exige la misma energia de activacion que el proceso en fase liquida. (author) [Russian] Radiatsionnoj polimerizatsii tverdykh i zamorozhennykh monomerov za poslednee vremya udelyaetsya bol'shoe vnimanie. EHtot vopros predstavlyaet bol'shoj interes kak s prakticheskoj tochki zreniya, tak i s tochki zreniya novykh teorij khimicheskoj kinetikich radiatsionnoj khimii. Kak izvestno, strogaya prostranstvennaya uporyadochennost' monomernykh edinits v polimere obuslavlivaet rezkoe uluchshenie fiziko-mekhanicheskikh svojstv bez izmeneniya khimicheskogo sostava. Dlya sinteza stereoregulyarnykh polimerov ispol'zuetsya printsip matritsy, t.e. monomernaya edinitsa strogo orientiruetsya v prostranstve putem obrazovaniya kompleksa s katalizatorom ili kakim-libo drugim veshchestvom. Naprimer, pri radiatsionnoj polimerizatsii ryada monomerov, orientirovannykh v klatratnykh kompleksakh mocheviny i tiomocheviny, polucheny kristallicheskie stereopegulyarnye polimery. Odnako naibolee prostym variantom yavlyaetsya orientatsiya monomera v sobstvennoj kristallicheskoj reshetke. Khotya mnogie teoreticheskie voprosy v ehtoj oblasti ostayutsya neyasnymi, prakticheskoe ispol'zovanie ehtogo sposoba ves'ma zamanchivo. Tak, pri radiatsionnoj polimerizatsii kristallicheskogo trioksana uzhe poluchen vysokokristallicheskij polioksimetilen. Trebuetsya, odnako, dal'nejshaya teoreticheskaya razrabotka ehtogo metoda. Neobkhodimo dlya kazhdogo otdel'nogo monomera vyyasnit' vklad razlichnykh vidov reaktsij, proiskhodyashchikh pri obluchenii i posleduptsem plavlenii tverdykh monomerov (spetsificheskaya radiatsionnaya reaktsiya, postpolimerizatsiya i polimerizatsiya v tochkakh fazovykh perekhodov) v obshchuyu kartinu protsessa. Vypolnennoe v poslednee vremya v Institute khimicheskoj fiziki podrobnoe issledovanie kinetiki radiatsionnoj tverdofaznoj polimerizatsii ryada monomerov s primeneniem kalorimetricheskogo metoda i s nablyudeniem signala EHPR pokazalo, chto spetsificheskaya radiatsionnaya reaktsiya v khode oblucheniya igraet sushchestvennuyu rol'. Posle okonchaniya oblucheniya protsessa polimerizatsii akrilonitrila (ot -196{sup o} do -140{sup o}C) i vinilatsetata (ot -196{sup o} do -100{sup o}C) prekrashchaetsya nesmotrya kak na sokhranenie formy i intensivnosti signala EHPR, tak i na bol'shoe vremya zhizni sozdavaemykh oblucheniem ionov. Rezul'taty ehtikh opytov svidetel'stvuyut o vozmozhnoj bol'shoj roli korotkozhivushchikh vozbuzhdennykh sostoyanij v radiatsionnoj tverdofaznoj polimerizatsii ryada monomerov. Takaya polimerizatsiya ''pod puchkom'' proiskhodit prakticheski bez ehnergii aktivatsii - v otlichie ot medlennoj postpolimerizatsii, idushchej s toj zhe ehnergiej aktivatsii, chto i zhidkofaznyj protsess. (author)}
place = {IAEA}
year = {1963}
month = {Nov}
}