The Influence of Silica Nanoparticles on the Thermal and Mechanical Properties of Crosslinked Hybrid Composites.

Tomasz Klepka,Beata Podkościelna,Dariusz Czerwiński,Bronisław Samujło

doi:10.3390/ma14237431

Abstract

This paper presents the synthesis and physicochemical characterization of a new hybrid composite. Its main goals are evaluating the structure and studying the thermal and mechanical properties of the crosslinked polymeric materials based on varying chemical properties of the compounds. As an organic crosslinking monomer, bisphenol A glycerolate diacrylate (BPA.GDA) was used. Trimethoxyvinylsilane (TMVS) and N-vinyl-2-pyrrolidone (NVP) were used as comonomers and active diluents. The inorganic fraction was the silica in the form of nanoparticles (NANOSiO2). The hybrid composites were obtained by the bulk polymerization method using the UV initiator Irqacure 651 with a constant weight ratio of the tetrafunctional monomer BPA.GDA to TMVS or NVP (7:3 wt.%) and different wt.% of silica nanoparticles (0, 1, 3%). The proper course of polymerization was confirmed by the ATR/FTIR spectroscopy and SEM EDAX analysis. In the composites spectra the signals correspond to the C=O groups from NVP at 1672–1675 cm−1, and the vibrations of Si–O–C and Si–O–Si groups at 1053–1100 cm−1 from TMVS and NANOSiO2 are visible. Thermal stabilities of the obtained composites were studied by a differential scanning calorimetry DSC. Compared to NVP the samples with TMVS degraded in one stage (422.6–425.3 °C). The NVP-derived materials decomposed in three stages (three endothermic effects on the DSC curves). The addition of NANOSiO2 increases the temperature of composites maximum degradation insignificantly. Additionally, the Shore D hardness test was carried out with original metrological measurements of changes in diameter after indentation in relation to the type of material. The accuracy analysis of the obtained test results was based on a comparative analysis of graphical curves obtained from experimental tests. The values of the changes course of similarity in the examined factors, represented by those of characteristic coefficients were determined based on the Fréchet’s theory.

Highlights

Hybrid materials belong to the new generation of materials
BPA.GDA including hydroxyl groups in its structure could affect with the silica nanoparticles by hydrogen bonds and weaker intermolecular interactions, contributing to its stronger incorporation into the polymeric network
The proposed system of monomers and nanofiller in the form of SiO2 results in obtaining hybrid nanocomposites having inorganic fragments composed of silica nanoparticles and silane groups (TMVS) as well as organic part from acrylic derivative of bisphenol A and NVP

Summary

Introduction

Hybrid materials belong to the new generation of materials They are defined as materials formed from a homogeneous mixture of inorganic and organic components, penetrating each other on a scale of less than 1 μm [1]. Most often organic-inorganic hybrid materials are obtained by mixing organic polymers (monomers) with inorganic compounds [2,3,4]. In this way, the obtained products are characterized by the properties that the individual components do not have [5,6,7,8]. The practically unlimited possibilities of combining organic and inorganic substances enable production of a wide range of new hybrid materials whose properties and applications will depend on the raw materials used in the synthesis [9,10]

Methods

Results

Conclusion