Template Synthesis of Calcium Phosphates in Nanoporous Polyolefin Films Obtained via Crazing Mechanism
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RIALS FOR ENSURING HUMAN VITAL ACTIVITY AND ENVIRONMENTAL PROTECTION
Template Synthesis of Calcium Phosphates in Nanoporous Polyolefin Films Obtained via Crazing Mechanism M. A. Moskvinaa, *, E. S. Trofimchuka, **, F. I. Grabovenkoa, ***, N. I. Nikonorovaa, ****, and A. L. Volynskiia, ***** aDepartment
of Chemistry, Moscow State University, Moscow, 119991 Russia *e-mail: [email protected] **e-mail: [email protected] ***e-mail: [email protected] ****e-mail: [email protected] *****e-mail: [email protected]
Received July 4, 2019; revised July 26, 2019; accepted July 29, 2019
Abstract—An alternative method for production of hybrid organic–inorganic nanocomposites based on porous polyolefin films (isotactic polypropylene, high density polyethylene), deformed via crazing mechanism in physically active media, and calcium phosphates is proposed. Film composite materials of different structure and containing 10–25 wt % of filler are obtained. Particles of calcium hydroxyapatite with a diameter of 15–50 nm are formed in these films at once in the pores of the polymer matrices with the development of a layer, the morphology of which is determined by the structure of the original porous films, and its parameters can be controlled by the reaction conditions. It is found that the composites obtained are characterized by anisotropy of mechanical properties, and the introduction of the calcium phosphate particles results in some increase in the mechanical characteristics of the polymer matrices. High-temperature heating (up to 700°C) of nanocomposites leads to burning out of the polymer matrix and formation of porous calcium hydroxyapatite residues consisting of nanoparticles with different morphology depending on the initial porous structure of polymer (from needle-shaped crystals with a length of 100–150 nm and about 10 nm in diameter to spheres with a diameter of 50–90 nm). The results obtained are relevant for the directional regulation of the structure and properties of bioactive substances and creation of modern materials for biomedical use. Keywords: calcium phosphates, polypropylene, polyethylene, crazing, porosity, morphology DOI: 10.1134/S207511332005024X
INTRODUCTION Considerable study has been given to creation of ceramic materials for medical use in recent years [1, 2] that are meant for application in reconstruction of bone tissue defects, forming as a result of pathological changes in the body, major surgeries, or injuries. The application of materials based on calcium phosphate possessing biocompatibility with living organisms and exhibiting activity toward formation of new bone tissue gives unique opportunities in this direction [3, 4]. There are some methods of production of porous inorganic materials in the literature [5–8]: compression sintering, sol-gel technology, chemical or electrochemical etching, foaming, template synthesis followed by matrix removal. The porous materials based on calcium phosphate are often synthesized by foaming via addition of porophores and followed by their high-
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