FORMATION OF RESIDUAL STRENGTH OF STRUCTURAL FIBER IN CONDITIONS AFTER FIRE
The article presents the results of dynamic mechanical tests of fiberglass specimens under the conditions of the effects of intense heating on them, which corresponded to the development of a slowly developing fire.
It is established that with intensive heating at the initial stage of fire, the considered type of fiberglass loses its initial strength, but then, upon cooling, acquires increased rigidity, while maintaining sufficient integrity and relative structural functionality.
In our view, this increase is due to the significant increase in the carbon fraction in the polymer binder with the formation of a more densely packed structure due to the formation of sites with associated aromatic fragments. At the same time, the drop in strength occurs due to the formation of a sufficient number of voids (pores and cracks), the occurrence of which is characteristic of materials of organic nature (plastics based on synthetic polymers) in the process of thermal oxidation destruction under intense heating. It is established that the degree of conservation of the load-bearing strength of the fiberglass can be arranged in the following order: bending> stretching> compression. This behavior of the material indicates the use of additional structural measures when using it as the supporting elements of construction and technological structures.
The determining factor in the observed modification of the composite is the extent of the passage of the pyrolytic transformations of the polymer bond, which can indirectly be characterized by a change in the dynamic mechanical properties of the material under intense heating.
The main role is played by the binder component - the epoxidized naphthalene type oligomer, whose function is reduced to the ability to play a role in the volume of the polymer matrix of coke formation germs.
The above composition of components and the method of its production allows to develop polymeric composite materials without the use of additional components - flame retardants (retardants), which complicate the technology of obtaining the composite and in some cases reduce its initial physical and mechanical properties.
Bilym, P.A., Mihajlyuk, A.P., Afanasenko, K.A. (2009) Zakonomernosti razuprochneniya konstrukcionnyh stekloplastikov v usloviyah narastaniya temperatury v rezhime standartnogo pozhara. Problemy pozharnoj bezopasnosti. Sb. nauch. tr., 25, 24 – 29.
Bilym, P.A., Mihajlyuk, A.P., Afanasenko, K.A. (2010) Vliyanie himicheskoj izomerizacii glicidilovyh efirov dinaftolov na sohranenie prochnosti kompozitov v usloviyah razvitiya standartnogo pozhara. Problemy pozharnoj bezopasnosti. Sb. nauch. tr., 27, 26 – 32.
Bilym, P.A., Mihajlyuk, A.P., Afanasenko, K.A. (2008) Skloplastik: patent na korisnu model № 37602 (Ukrayina), S 08J 5/00.; zayavnik ta patentovlasnik UGZU. –u200803048; zayavl.11.03.2008; opubl.10.12.2008, Byul. № 23
Bilym, P.A., Mihajlyuk, A.P., Afanasenko, K.A. (2008) Harakter izmeneniya dinamicheskogo modulya sdviga stekloplastika pri nagreve v usloviyah blizkih k nachalnoj stadii razvitiya otkrytogo pozhara. Problemy pozharnoj bezopasnosti, 24, 16-21
Bilym, P.A., Mihajlyuk, A.P., Afanasenko, K.A., Olejnik, V.V. (2010) Issledovanie metodom EPR piroliticheskih prevrashenij v stekloplastikah pri teplovyh vozdejstviyah pozhara. Problemy pozharnoj bezopasnosti: Sb. nauch. tr., 27, 33 – 38.
Bilym, P.A., Mihajlyuk, A.P., Afanasenko, K.A. (2009) Osobennosti vysokotemperaturnogo strukturirovaniya polimernyh svyazuyushih stekloplastika na nachalnoj stadii razvitiya pozhara. Problemy pozharnoj bezopasnosti: Sb. nauch. tr., 26, 25 - 31.
Berlin, A.A., Gejderih, М.А., Davidov, В.Е. y dr. (1973) Himiya polisopryazhennyh sistem. – Moskva: Himiya, 271.
Gracheva, L.I. (2006) Termicheskoe deformirovanie i rabotosposobnost materialov teplovoj zashity. Kiev: Nauk. dumka, 294.
Bilym, P.A., Mihajlyuk, A.P., Afanasenko, K.A. (2008) Issledovanie poristosti, pronicaemosti i struktury koksovyh ostatkov poliepoksidnyh svyazuyushih. Problemy pozharnoj bezopasnosti: Sb. nauch. tr., 23, 48 – 56.
The authors who publish in this collection agree with the following terms:
• The authors reserve the right to authorship of their work and give the magazine the right to first publish this work under the terms of license CC BY-NC-ND 4.0 (with the Designation of Authorship - Non-Commercial - Without Derivatives 4.0 International), which allows others to freely distribute the published work with a mandatory reference to the authors of the original work and the first publication of the work in this magazine.
• Authors have the right to make independent extra-exclusive work agreements in the form in which they were published by this magazine (for example, posting work in an electronic repository of an institution or publishing as part of a monograph), provided that the link to the first publication of the work in this journal is maintained. .
• Journal policy allows and encourages the publication of manuscripts on the Internet (for example, in institutions' repositories or on personal websites), both before the publication of this manuscript and during its editorial work, as it contributes to the emergence of productive scientific discussion and positively affects the efficiency and dynamics of the citation of the published work (see The Effect of Open Access).