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Liquid Crystals and their Application Russian Journal Zhidkie kristally i ikh prakticheskoe ispol'zovanie Жидкие кристаллы и их практическое использование |
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Zhidk. krist. ikh prakt. ispol'z. = Liq. Cryst. and their Appl., 2013, 1, 65—70. |
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Thermotropic Mesomorphism of Doped Phenoplasts
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N. A. Kropotova, O. E. Storonkina, A. A. Razymov
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Author affiliations Ivanovo Institute of the State Fire Service, Stroitelei pr. 33, Ivanovo, 153040 Russia
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Abstract Manifestation of thermotropic mesomorphism in phenoplasts dopped with crystalline filler – hexamethylenetetramine (HMT) is investigated. Crystallization of phenol formaldehyde resin occurs in a temperature range from melting point to glass transition temperature. Heating of the studied samples caused the appearance of spherulitic structures (domains), the number of which grew with rising temperature, and their sizes slightly increased. In an alternating electric field new structural formations with crosswise inclusions like cylindrical domains in liquid crystals with positive dielectric anisotropy were found. Temperature dependences of contact angle and conductivity of resins were stud-ied. Introduction of crystalline filler improves wear resistance and mechanical durability of abrasive tools, in which production resins are used.
Keywords: thermojet composites, spherolit structures, domains, polymerization, conductivity, contact angle
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