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The primary objective of this study was to improve montmorillonite clayplatelet separation in vinyl ester resin matrix by organically modifying the nanoclay platelet with a partially reactive onium salt. The reactive onium salt (-undecylenyl amine hydrochloride) was synthesized from commercial -undecylenyl alcohol through a series of synthetic conversions. Nonreactive onium salt (undecyl amine hydrochloride) was made from commercial undecyl amine. These salts were characterized with 1 H and 13 C NMR and Fourier transform infrared techniques. The relative amounts of exfoliated, intercalated, and as-treated clay and the size of the clay particle aggregates depended significantly on the composition of clay and the processing conditions. When the clay was ion-exchanged with a mixture of reactive and nonreactive onium salts, a partially exfoliated vinyl ester resin polymer nanocomposite was formulated. The addition of a comonomer styrene and high-intensity ultrasonic mixing produced vinyl ester nanocomposite with the highest degree of clay-platelet exfoliation.

Polyvinyl alcohol (PVA) nanocomposites were made using two different cellulose nanocrystals (CNCs). Sugarcane bagasse‐based CNC and a commercial CNC were used in preparing nanocomposites. Both types of nanocomposites were prepared by solution casting method at 5 wt% CNC. PVA and nanocomposites films were also stretch‐drawn four times to study the nature of reinforcement by two different CNCs. Fourier transform infrared spectroscopy was used to examine functional group characteristics. Nanocomposite morphology and crystalline structures were analyzed using a scanning electron microscope and X‐ray diffraction, respectively. Thermogravimetric analysis and differential scanning calorimetry were used to study thermal properties. Tensile properties were used to study mechanical properties. Commercial CNC reinforcement improves the tensile properties of PVA. However, laboratory CNC reinforcement decreases the tensile properties of PVA due to nanocrystal agglomeration and uneven dispersion. All stretch‐drawn nanocomposite films showed a significant increase in tensile strength and modulus values at the expense of strain at break. Water absorption of PVA/commercial CNC nanocomposites was slightly higher than that of pure PVA.

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Summary: Nanocomposites were formulated by curing a sonicated mixture of epoxy resin, C18 clay, and acrylic rubber dispersants. At 5.5 phr (parts per hundred) organoclay loading and a rubber concentration of 15 phr, the tensile‐failure strain of the nanocomposite was found to be higher than that of epoxy nanocomposite, rubber‐dispersed epoxy, and pristine epoxy. A plausible mechanism for improvement of the failure strain of nanocomposites is proposed.