IN SITU SYNTHESIS OF POLYMER‐EMBEDDED NANOSTRUCTURES

Tveten

Miranti

et al. 2020

J Sol-Gel Sci Technol

Polymer nanocomposites are often produced using in situ approaches where an inorganic filler (as the dispersed phase) is synthesized directly in an organic matrix. Such an approach generally leads to improved dispersion and reduced agglomeration of the filler material. Epoxy-based nanocomposites have demonstrated promising properties for application as high-voltage insulation materials. In this work, a sol-gel based method has been adapted to synthesize surface-functionalized SiO 2 in situ in epoxy. The synthesized SiO 2 moieties were dispersed in clusters of 10-80 nm, and formed chemical bonds with the epoxy monomers via a silane coupling agent. Raman spectra show the formation of four-membered D 1 rings, which may be part of a cage-like structure similar to that of polyhedral oligomeric silsesquioxanes (POSS). SAXS measurements indicate that the SiO 2 clusters consist of a hierarchical structure with an increasing fractal dimension with increasing SiO 2 content. The nanocomposites displayed improved thermal stability, while the glass transition behavior varied depending on the structure and content of the SiO 2 moieties. While the relative permittivity showed no significant changes from that of pure epoxy, the onset of the dielectric relaxation changed with the SiO 2 structure and content, similar to the behavior observed for the glass transition.

Section: Introductionmentioning

confidence: 99%

In situ synthesis of epoxy nanocomposites with hierarchical surface-modified SiO2 clusters

Tveten

Miranti

et al. 2020

J Sol-Gel Sci Technol

“…As a result, nanoparticles possess a significantly higher surface energy than micrometer‐sized particles, and will tend to form clusters or agglomerates to reduce the total surface area and minimize the available surface energy. Agglomerate formation is further driven by the incompatibility between the hydrophilic inorganic particles and the hydrophobic organic polymer chains, and the large difference in surface energy between them . Composite materials consisting of well‐dispersed nanoparticles will therefore have a larger area available where the polymer chains and inorganic particles can interact, compared to the micrometer‐sized counterparts.…”

Section: The Structure Of Epoxy Nanocompositesmentioning

confidence: 99%

Epoxy‐Based Nanocomposites for High‐Voltage Insulation: A Review

Tveten

Glaum

et al. 2018

Adv Elect Materials

Epoxy nanocomposites, with inorganic oxide nanoparticles as filler, can exhibit novel property combinations, such as enhanced mechanical strength, higher thermal conductivity, increased dielectric breakdown strength, and reduced complex permittivity. Therefore, they have interesting applications in nanodielectrics, such as high‐voltage insulation materials or in microelectromechanical systems. The primary challenge in the processing of nanocomposites is achieving a homogeneous dispersion of the nanoparticles. The dispersion quality affects the interfaces between the organic and the inorganic components, which can determine the final properties of the nanocomposite. Here, the processing methods and the resulting dielectric, mechanical, and thermal properties of epoxy nanocomposites with inorganic oxide fillers are presented. Functionalization of the nanoparticle generally improves the dispersion of the particles in the polymer matrix. Different oxide fillers are observed to have similar effects on the properties of the nanocomposites. Epoxy‐based nanocomposites exhibit improved dielectric breakdown strength and lower complex permittivity with inorganic oxide nanoparticles at low filler contents, compared to conventional composites with micrometer‐sized particles. While there are some inconsistencies in the findings, which may be attributed to differences in the dispersion quality, an improved understanding of the nanoparticle–epoxy interfaces in nanocomposites will enable tailoring of the desired properties, opening new avenues for application.

“…These interactions are correlated to the size, shape, size distribution, and dispersion state of the nanoparticle fillers. However, nanoscale materials have a tendency to agglomerate in order to minimize the high surface energy [21,22]. The agglomeration of nanoparticles will reduce the interfacial area and the interactions with the polymers in nanocomposites, thereby negating the potential benefits of using nanoscale fillers.…”

Section: Introductionmentioning

confidence: 99%

“…The resulting inhomogeneity in the nanocomposites can deteriorate the properties of the material. Surface functionalization of the nanoparticles may help prevent agglomeration of the nanoparticles, or reduce any phase separation due to the incompatibility between the hydrophilic inorganic fillers and the hydrophobic polymer matrix [21,24]. The surface modification can be done using either physical interactions (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…An innovative approach to achieve a homogeneous dispersion is the in situ synthesis of inorganic nanoparticles in the polymer matrix, using techniques such as sol-gel chemistry, reverse microemulsion, or hydrothermal/solvothermal synthesis [2][3][4]12,19,21,22,24,28,29]. These methods typically involve the mixing of precursors with a non-reactive solvent and the monomer/polymer, where the reaction of the precursors initiates the synthesis of particles either before or during polymerization [21,25]. This bottom-up approach to the preparation of nanocomposites can enable increased control over the structure and properties of the nanocomposite by incorporating particle generation, surface modification, and integration into the polymer matrix in one process.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

<em>In Situ</em> Synthesis of Hybrid Inorganic-Polymer Nanocomposites

Dalod

Balcı

et al. 2018

Preprint

Hybrid inorganic-polymer nanocomposites can be employed in diverse applications due to the potential combination of desired properties from both the organic and inorganic components. The use of novel bottom-up in situ synthesis methods for the fabrication of these nanocomposites is advantageous compared to top-down ex situ mixing methods, as it offers increased control over the structure and properties of the material. In this review, the focus will be on the application of the sol-gel process for the synthesis of inorganic oxide nanoparticles in epoxy and polysiloxane matrices. The effect of the synthesis conditions and the reactants used on the inorganic structures formed, the interactions between the polymer chains and the inorganic nanoparticles, and the resulting properties of the nanocomposites are appraised from several studies over the last two decades. Lastly, alternative in situ techniques and the applications of various polymer-inorganic oxide nanocomposites are briefly discussed.