Processing-property relationships in epoxy resin/titanium dioxide nanocomposites

摘要: In situ precipitated titanium dioxide nanoparticles improve the physical properties of polymer composites. Since pioneering work at Toyota Research Center on exfoliated montmorillonite in a nylon matrix, extensive studies have been performed nanocomposites an effort to better integrate organic and inorganic phases. Inorganic fillers, such as silicon oxides, are widely used because their remarkable enhancement mechanical, electrical, barrier, flame-retardancy polymers. The dispersion size fillers determine performance and, despite numerous methods processing conditions reported literature, universally simple method scale up distribution nanofillers remains challenge. A significant part our research involves formulation novel nanodielectrics that can withstand high electric fields exhibit superior mechanical performance. Focusing operating cryogenic temperatures, group developed for nucleating (TiO{sub 2}) polyvinyl alcohol. We also applied this variety matrices. Here, we present recent resin filled with TiO{sub 2} nanoparticles. Using particle-precursor solution from which precipitates, nucleated within epoxy resinmore » Araldite 5808 (Huntsman Advanced Materials Inc., USA). fabricated nanocomposite films low weight percentages ({approx}2.5%) avoid formation large aggregates interfaces. morphology synthesized shown by low- high-magnification transmission-electron-microscopy (TEM) images. particles ({le}5nm diameter) uniformly form evenly distributed nanometer-sized clusters matrix. This differs significantly obtained conventional, ex synthesis requires shear mixing technique, (also {le}5nm polyethylene glycol - see Figure 1(c) subsequently mixed them resin. process, even concentrations (1% weight), resulted several hundred nanometers size. optical, thermomechanical, electrical measurements systems similar fractions evaluate impact particle macroscopic nanocomposite. agreement TEM images, UV-visible transmittance spectra show same optical unfilled owing small particle-cluster Because comparable wavelength light visible range, specimen showed decreased transmittance, producing opaque composite. Moreover, found creating weak interfaces between phases degrades thermomechanical specimen. exhibited compared both over entire temperature range. Notably, lowest measured (-145 C), increase storage modulus (G') relative is approximately 30%. Furthermore, technique did not degrade thermodynamic network. glass-transition (T{sub g}) unchanged. contrast, displayed 55% decrease Tg associated degradation dielectric under fields. dielectric-breakdown strength (EBD) lower than On other hand, uniform system yielded 40% improvement EBD 0.1% failure probability. conclusion, epoxy-resin spatial matrix improves noteworthy strength, combined properties, be develop advanced insulation materials. Additionally, does require potentially fabricate robust, optically transparent scales.« less