Structure of Polytetrafluoroethylene Modified by the Combined Action of γ-Radiation and High Temperatures

Polymers

Alexander Sergeevich Smolyanskii¹  Lev Vladimirovich Moskvitin¹  Dmitrii Pavlovich Kiryukhin²  Pavel Prokof’evich Kusch²  Ol’ga Alekseevna Koshkina³  Ekaterina Dmitrievna Politova³  Leonid Izrailevich Trakhtenberg³  Sergei Vital’evich Slesarenko⁴  Mikhail Aleksandrovich Arsentyev⁴ 

[1] High Energy Chemistry and Radioecology Department, D. Mendeleev University of Chemical Technology of Russia, Miusskaya Ploshchad 125047, Moscow, Russia;Laboratory of Cryochemistry and Radiation Chemistry, The Institute of Problems of Chemical Physics, Russian Academy of Science, Chernogolovka 142400, Moscow, Russia;Laboratory of Functional Nanocomposites, N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Science, Moscow 119991, Moscow, Russia;Technology Department, Quantum R LLC, Skolkovo 125319, Moscow, Russia;

关键词: polytetrafluoroethylene;    ionizing radiation;    high temperatures;    modification;    crystallization;    cross-linking;   

DOI  :  10.3390/polym13213678

来源: DOAJ

【 摘 要 】

By means of X-ray computed microtomography (XCMT), the existence of a developed porous structure with an average pore diameter of ~3.5 μm and pore content of ~1.1 vol.% has been revealed in unirradiated polytetrafluoroethylene (PTFE). It has been found that the combined action of gamma radiation (absorbed dose per PTFE of ~170 kGy) and high temperatures (327–350 °C) leads to the disappearance of the porous structure and the formation of several large pores with sizes from 30 to 50 μm in the bulk of thermal-radiation modified PTFE (TRM-PTFE). It has been established by X-ray diffraction (XRD) analysis that the thermal-radiation modification of PTFE leads to an increase in the interplanar spacings, the degree of crystallinity and the volume of the unit cell, as well as to a decrease in the size of crystals and the X-ray density of the crystalline phase in comparison with the initial polymer. It is assumed that the previously-established effect of improving the deformation-strength and tribological properties of the TRM-PTFE can be due not only to the radiation cross-linking of polymer chains but also to the disappearance of the pore system and to the ordering of the crystalline phase of PTFE.

【 授权许可】

Unknown