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Electrospinning is used to prepare hydrophobic and self-cleaning polysulfone (PSf) surfaces. The effects of PSf concentration in Dimethylformamide (DMF) solvent and electrospinning process parameters on the surface structure and hydrophobicity are investigated. The experimental results show that depending on PSf concentration, three types of morphologies are obtained: beads, beads-on-strings, and free-beads fibers. The surface hydrophobicity depends mainly on the resultant surface morphology, and the existence of beads increases hydrophobicity. The contact angle (CA) is found to increase from 73°for smooth PSf surface to more than 160°for surfaces formed by electrospinning. Moreover, the contact angle hysteresis (CAH) was generally less than 10°f or all the chemistries. It is noted that increasing the PSf concentration leads to the formation of beads-on-string and freebeads fiber structures; this morphological change is accompanied by a reduction in the contact angle. Surface structures are found to be more sensitive to electrospinning feed rate than to electrospinning voltage; however, these two parameters have a negligible influence on the hydrophobicity. Porosity measurements of different chemistries show an average pore size in the range 3-8 microns. The thickness of PSf mats was variable, from as low as 10 μm to as high as 70 μm.

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.

Epoxy‐clay nanocomposites were synthesized by high shear mixing (HSM) technique using diglycidyl ether of bisphenol A (DGEBA) epoxy reinforced by Nanomer I.30E nanoclay. Disordered intercalated with some exfoliated structure were found in the resultant nanocomposites. The fabricated samples were exposed to water and crude oil to investigate the effect of nanoclay addition on diffusivity and amount of liquid uptake. The results showed good improvement in the barrier properties of epoxy as a result of clay addition. The average reduction in diffusivity and maximum water uptake for nanocomposites containing 1% nanoclay were 51% and 8%, respectively. The maximum water uptake was about double the maximum oil ingress for both neat epoxy and nanocomposites. Obvious degradations in thermal and mechanical properties of neat epoxy and nanocomposites were observed as a result of liquid uptake; with less severe impact on nanocomposites. The reduction in glass transition temperature was about 8% for each 1% of water uptake for nanocomposites as compared to 15% for neat epoxy. The tensile strength and the elastic modulus of neat epoxy and nanocomposites were adversely affected by water and oil uptake while the fracture strain was slightly improved; a behavior found to be proportional to the amount of liquid uptake. The diffusion mechanism of water in neat epoxy was well predicted by Fickian model, while that of the nanocomposites was better fitted with Langmuir model. POLYM. COMPOS., 35:318–326, 2014. © 2013 Society of Plastics Engineers