Nanocomposites and nanomaterials

SiO2/PLGA hybrid nanocomposites 

Kyshkarova V.V., Melnyk I.V.

Institute of Geotechnics, Slovak Academy of Sciences
Watsonova 45, 040 01 Košice, Slovak Republic. 
E-mail: kyshkarova@saske.sk
Much attention has been devoted in recent years to developing a new class of modern materials - hybrid organic-inorganic nanocomposites. These composites have a wide range of potential applications, and one of them is the removal of heavy metals from industrial waters. Thereby, the inorganic part contributes to the stability of materials (silica) while the organic part – usually polymers – is chosen for its functional chemical properties (PLGA). 
This study presents the use of sol-gel technology for production of the hybrid composites (Table 1). Synthesis of such composites was carried out in acetone and tetraethylortosilicate (TEOS) was applied as silica source. PLGA (poly(lactic acid-co-glycolic acid) was taken as the polymer component. Firstly, TEOS was prehydrolized by HCl, for the mixture with polymer different catalyst were used: NaF, NH4OH. As well as crosslinking reagent ethylene glycol (EG) was added in synthesis procedure with NaOH catalyst. According to the composition and catalyst the samples were labelled (Table 1).

Table 1. Composition and characteristics of the hybrid composites
Sample	Elemental analysis data, %	pI	Cacid, mmol/g	SBET, m2/g	
	C	N	H				
SiO2/PLGA-NaF	18.5	0.1	4.2	2.23	5.6	22	
SiO2/PLGA-NH4OH	5.1	0.1	2.5	3.5	4.6	15	
SiO2/PLGA-EG-NaOH	5.6	0.2	1.4	2.08	5.4	294	

The structure and properties of the obtained composites were characterized by elemental analysis, acid-base titration, electrokinetic potential measuring, IR spectroscopy, TGA, and SEM. It was shown that the acquired composites are stable in the water spherical particles containing acid groups. The study of adsorption properties indicated the possibility of using such materials as adsorbents for heavy metals.

Acknowledgment: The research has been supported by VEGA 2/0156/19, APVV-19-0302, H2020-MSCA-RISE-2016-NANOMED No734641 projects.