Nanocomposites and nanomaterials 

Structure and properties of  POSS-containing nanocomposites based on polyurethane matrix
L.V.Karabanova, L.A. Honcharova, N.V. Babkina, V.I. Shtompel
1 Institute of Macromolecular Chemistry NASU, 48 Kharkivske shose, Kyiv 02160, Ukraine, E-mail: lyudmyla_karaban@ukr.net
       The nanocomposites based on Polyurethane (PU) matrix and 1,2-propandiol-isobutyl-POSS, used as inorganic nanofiller with reactive OH-groups, were created and peculiarity of structure by SAXS and WAXS, dynamic mechanical properties by DMA and morphology by SEM were investigated.
	
b

	Fig.1 Small angle 
curves for PU (1),
POSS (6) and for 
the nanocomposites (2-5) (a); and SEM image of  PU/POSS nanocomposite with 5% of POSS (b).	
   The wide and small-angle x-ray scattering  have shown that the hydroxy-POSS have done greater effect on the microphase structure of the PU. This is reflected in the shift of the interference maximum to the larger values ​​of the scattering angles (2 ), and, accordingly, in the decrease of the value D with POSS content (Fig. 1a). A decrease in the intensity of the interference maximum of PU was detected, however it is extremely dependent on the content of the POSS. This may indicate that hydroxy-POSS could  participate in the reaction of urethane formation using one of the terminal hydroxyl groups, which allow to be implanted into the chain between crosslinks of PU. But with an increase of POSS amount, a certain part of the POSS is not implanted, but plays a role of the nanofiller in the system. This correlates with the results of the research have done by the FTIR method [1].
     By DMA investigations the glass transition is shifted to high temperatures, also the tan δ peak regularly decreases with POSS content indicating the restriction of PU segmental motion in the nanocomposites compare with the matrix. 
     By SEM was found that homogeneous structure of native PU became more segregated with POSS content. The POSS particles aggregation in the form of rectangular microdomains for PU5, PU10 nanocomposites were observed (Fig.1b). 
1.Karabanova L.V. Honcharova L.A,. Sapsay V.I., Klymchuk D.O. Synthesis, morphology and thermal properties of the POSS-containing polyurethane nanocomposites// Chem.Phys. Tech.Surf.-2016.-7, P. 413-420.