Effect of a novel green modification of alumina nanoparticles on the curing kinetics and electrical insulation properties of epoxy composites

Abstract

A novel green surface modification was successfully implemented on alumina nanoparticles using chitosan (CS) to prevent nanoparticles' aggregation. To evaluate the surface changes of nanoparticles, FTIR, TGA, TEM, and SEM analyses were used. The cure kinetics of the uncured samples was analyzed by DSC. Different methods such as KAS, Friedman, Starink, and FWO were applied to measure the activation energy. The activation energy of epoxy reinforced with chitosan‐functionalized alumina (epoxy/[CS‐EPO‐alumina]) was less than that of epoxy reinforced with alumina (epoxy/alumina), which was a confirmation of the positive effect of CS on curing reaction kinetics. Using the Malek method, the Sestak‐Berggren autocatalytic equation was chosen to investigate the cure kinetics of the epoxy. It was found that the Sestak‐Berggren equation is well matched with the experimental data and the model was suitable to predict the epoxy curing reaction reliably. Moreover, the glass transition temperatures of all samples were approximately the same. The effect of surface modification of alumina on the electrical insulating behavior of epoxy was also studied. It was found that CS functionalized alumina (CS‐EPO‐alumina) increased volume resistivity of epoxy at a temperature range of 30 to 80°C more than that of alumina. Electric stability and breakdown strength of epoxy/alumina and epoxy/(CS‐EPO‐alumina) also enhanced, where epoxy/(CS‐EPO‐alumina) experienced a further increase compared to epoxy.

Polystyrene/polyolefin elastomer/halloysite nanotubes blend nanocomposites: Morphology‐thermal degradation kinetics relationship

“…The FTIR spectra corresponding to PS and POE phases, which were recorded at the maximum degradation temperature of around 420 C, are indicated in Figure 8A. Regarding the PS phase, some considerable absorption peaks can be detected for all samples that are assigned to the sp 2 C H stretching band (3000 cm À1 ), sp 3 β C H (α methyl) stretching (2975 cm À1 ), aromatic ring (1600 and 1505 cm À1 ), C═C (1635 cm À1 ), and C H out-of-plane deformations (900 and 675 cm À1 ), which are characteristic of the aromatic substitution pattern. [79][80][81][82] These findings reveal that the main reaction is the depolymerization of PS to styrene monomers, which is in line with other research works.…”

Environmentally friendly polypropylene/poly (trimethylene terephthalate) blend fibers: Resiliency and dyeability

“…To investigate the light-fastness properties, the dyed fabrics were exposed to daylight (ISO105-B01), and the color changes were compared to the so-called blue scale (1)(2)(3)(4)(5)(6)(7)(8). Also, to study the washing-fastness properties, the experiments were carried out according to ISO105-Co1 standard, and the color changes were compared to the so-called gray-scale (1-5).…”

“…Owing to the usage of polymers in different aspects of science, technology, and industry, their importance is steadily enhancing. [1][2][3][4][5][6][7][8] Polypropylene (PP) yarn is a favorable candidate for various engineering applications due to its ease to preparation, low density, good resistance to many chemicals, low cost, lightness, good mechanical properties, etc. 9,10 However, PP suffers from some limitations such as photo-chemical degradation, poor resiliency, low affinity to absorb dyestuff, lack of hydrophilic groups, etc.…”

Evaluating the mechanical, thermal, and antibacterial properties of poly (lactic acid)/silicone rubber blends reinforced with (3‐aminopropyl) triethoxysilane‐functionalized titanium dioxide nanoparticles

“…Polymers have drawn much attention because of their diversity, versatility, and practicality. [1][2][3][4][5][6][7][8][9][10][11][12][13] Poly(lactic acid) (PLA), derived from renewable resources, exhibits outstanding properties such as good strength, high modulus, and optical clarity. Thanks to these remarkable features, PLA is one of the most widely utilized biodegradable and biocompatible plastics used in the industrial packaging field or in the biocompatible/bioabsorbable medical device market.…”