Dielectric properties and thermal destruction of poly(dimethylsiloxane)/Fe2O3/SiO2 nanocomposites

Effects of surface modification and thermal annealing on the interfacial dynamics in core–shell nanocomposites based on silica and adsorbed PDMS

“…4a and 5a). In our previous studies on similar core-shell systems, it has been demonstrated that S relaxation becomes weaker as the degree of polymer adsorption (surface coverage of the particles) increases [12,13,17]. In work in progress on nanocomposites based on PDMS (the same and similar with those in the present study) we obtain similar results imposed by water content, in particular, an increase in the dielectric strength of S relaxation with increasing hydration level.…”

“…Zirconia content according to XRD, C ZrO2 , specific surface area as recorded by Nitrogen adsorption-desorption isotherms, S BET , average volume of pores, V p , of mesopores (details in text), V meso , and of macropores, V macro . value for neat PDMS is in agreement with previous studies of PDMS [9,12,41,44]. Interestingly, T g of the core-shell systems is by 2 K lower than that of neat PDMS and it is further reduced on addition of nanozirconia by 1-8 K. DC p,n for nanocomposites of 40 wt% PDMS is smaller than for neat PDMS.…”

“…High S BET for nanosilicas with mainly textural porosity (e.g. fumed silicas A-240, A-300, A-380 [28,39,48]) has been previously shown to describe well high degree of accessibility for both the gas molecules and the PDMS chains [12,13,17]. The decrease of S BET after modification with zirconia was suggested to originate from the development of zirconia nanoparticles mainly onto the external silica surfaces, reducing this way their roughness.…”

“…Due to the low volume of each nanoparticle the polymer may potentially interact with the filler at higher surface areas in nanocomposites, as compared to macroscopic particles at the same loadings in conventional composites [2]. Thus, the most widely adopted concept for rationalizing improvements of materials properties involves the existence of a fraction of polymer at interfaces between particles and polymer, characterized by modified structure [3][4][5][6][7], dynamics [8][9][10][11] and thermal stability [12,13], as compared to the bulk. The properties of interfacial polymer may affect significantly or even dominate the behavior of the whole system [14].…”

Dielectric dispersion and relaxation studies of melt compounded poly(ethylene oxide)/silicon dioxide nanocomposites

“…Our survey of literature revealed that, so far the PEO and SiO 2 interactions and their effect on the polymer physico-chemical properties are characterized by rheological, differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), dynamical mechanical analysis (DMA), X-ray diffraction (XRD) scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements [1,[3][4][5][6][7]19]. Besides these experiments, the dielectric relaxation spectroscopy (DRS) is also a powerful tool for the study of polymer and nanofiller interactions and their effect on polymer dynamics in the PNC materials [20][21][22][23][24][25][26][27][28][29][30][31]. Further, the investigation on dielectric properties of such PNCs can provide the in-depth discussion of nanodielectrics, which is an emerging and fast-moving topic in electrical insulation for microelectronic devices.…”