Nanocomposites and nanomaterials

Structure and thermophysical properties of nanocomposites based on polyethylene oxide and organoclay nanoparticles
Bilyi S.A.1, Lysenkov E.A.1, Klepko V.V.2
1Department of Polymer Physics, Institute of Macromolecular Chemistry 
NAS of Ukraine.
Kharkivske Sh., 48, Kyiv-02160, Ukraine.

2Laboratory of Nanocomposite Materials, Petro Mohyla Black Sea National University.
68 Desantnykiv Str., 10, Mykolaiv-54003, Ukraine.
E-mail: ealysenkov@ukr.net

Polymer nanocomposites containing organoclay nanoparticles have been the subject of intensive research for the past two decades. The growing interest in the study of these systems is due to the fact that they have better mechanical stability and higher thermal stability compared to other composite materials. The aim of this work was to study the influence of the nature and content of anisometric nanofillers of different morphology (montmorillonite (OMMT) and laponite (OLP)) on the structure and thermophysical properties of nanocomposites based on polyethylene oxide (PEO).
As a result of research, it was shown that the structure and thermophysical properties of nanocomposites based on PEO significantly depend on the nature and content of organoclay. It is established that in the systems filled with OMMT, partial intercalation processes take place, while in the systems containing OLP the processes of complete exfoliation are observed. From the data of X-ray diffraction analysis and differential scanning calorimetry it can be seen that the introduction of OLP leads to greater amorphization of the system than the introduction of OMMT. The presence of OLP in the system, in contrast to OMMT, promotes the formation of larger crystallites, which leads to an increase in the melting point of PEO-OLP nanocomposites.
It is shown that the introduction of fillers reduces the relaxation time of PEO polymer chains. For the PEO-OMMT system, the electrical conductivity increased with increasing filler content, and for the PEO-OLP system, on the contrary, it decreased. This difference is due to a change in free volume, which has a decisive influence on the processes of charge transfer in systems of this type. It has been shown that the introduction of OMMT leads to an increase in free volume, and the introduction of OLP, respectively, to its reduction.