Effect of High Shear Mixing Parameters and Degassing Temperature on the Morphology of Epoxy-Clay Nanocomposites

Abstract

Epoxy-clay nanocomposites were prepared by high shear mixing method using Nanomer I.30E nanoclay as nano-reinforcement in diglycidyl ether of bisphenol A (DGEBA). The effect of mixing speed and time on the nature and degree of clay dispersion were investigated by varying the mixing speed in the range of 500-8000 RPM and mixing time in the range of 15-90 minutes. The effect of degassing temperature on the morphology of the resultant nanocomposites was also studied. Scanning and transmission microscopy (SEM & TEM) along with x-ray diffraction (XRD) have been used to characterize the effect of shear mixing speed, mixing time and degassing temperature on the structure of the resultant nanocomposites. The SEM, TEM and XRD examinations demonstrated that the degree of clay dispersion was improved with increasing the high shear mixing speed and mixing time. The results showed that the optimum high shear mixing speed and mixing time were 6000 rpm and 60 min, respectively. It was observed that the structure of the nanocomposites that have been degassed at 65oC was dominated by ordered intercalated morphology while disordered intercalated with some exfoliated morphology was found for the sample degassed at 100oC for the first 2 hours of the degassing process.

A two-parameter approach to assessing notch fracture behaviour in clay/epoxy nanocomposites

“…Furthermore, the behaviour of the produced nanocomposites is known to be that of brittle materials [1,5,35].…”

“…An intercalated or exfoliated morphology of epoxy-clay nanocomposites can be obtained depending on the mixing method and the type of epoxy and nanoclay used. Generally, exfoliated structures are reported to possess better properties than intercalated ones since more reinforcement elements are available that carry the applied load in the exfoliated morphology [1,5].…”

“…Improvements in mechanical properties such as the modulus of elasticity, tensile strength and fracture toughness due to clay addition have been reported in some studies [1][2][3][4][5][6][7][8][9][10][11], while other researchers found that nanoclay addition had negative or at best no effect on these properties [12][13].…”

“…Extensive research work has been conducted to investigate the effect of nanoclay addition on the properties of different types of polymer matrices [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].In fact, the properties of epoxyclay nanocomposites are highly dependent on the resultant morphology, which illustrates the degree of clay dispersion into the epoxy matrix [1,3]. An intercalated or exfoliated morphology of epoxy-clay nanocomposites can be obtained depending on the mixing method and the type of epoxy and nanoclay used.…”

“…type samples of neat epoxy and epoxy-clay nanocomposites containing clay loadings of 3 (NC 3%) and 5 wt% (NC 5%) were fabricated. The nanocomposites were prepared according to the optimised curing and degassing conditions and high shear mixing technique developed in an earlier work[1,5,[33][34][35]. XRD, SEM and TEM analyses have revealed that these optimised conditions result in an epoxy/clay nanocomposite with a combination of disordered intercalated and exfoliated morphology.…”