Foaming‐structural relationship of rotational molded nanocomposite foams: Box–Behnken response surface methodology implementation

Rotational molded foam is known as one of the most popular types of polymeric foams due to its unique properties. Hence, the production of rotational molded foam samples has been well‐addressed in the foam literature, and several researchers have tried to produce these samples using different approaches. However, there is no comprehensive research that investigates the structural properties of nanocomposite foam samples produced by a two‐step process of rotational molding and batch foaming. Therefore, the effect of nanoclay and foam processing parameters on the structural properties of the samples produced by this method was investigated in this study. For this purpose, the Box–Behnken design of response surface methodology was used. The results revealed that the foaming temperature was the most effective parameter on cell density and expansion ratio. Also, the foaming time was reported as the most effective parameter on the cell size. Then, the response variables were subjected to single‐ and multi‐objective optimizations. Finally, the addition of 1.2 wt% of nanoclay, the foaming temperature of 141°C, and the foaming time of 85 s were introduced as the most optimal conditions to simultaneously achieve maximum cell density and expansion ratio and minimum cell size in the rotational molded nanocomposite foam samples.