Poly(methyl methacrylate)/poly(urethane-urea)-based nanocellular foams reinforced with kaolin

The nanocellular foams were designed using novel poly(urethane-urea) (PUU) and poly(methyl methacrylate) (PMMA) blend matrix and layered silicate (kaolin) reinforcement. In this regard, a mixture of cyclopentane and isopentane was used for the reactive foaming. The morphological, mechanical, thermal, and flame-retardant properties of PMMA/PUU/kaolin nanocomposites and foams were investigated. The kaolin acted as a nanofiller as well as nucleating agent to produce nanocomposite foams. With the addition of nanofiller, the nanocellular foams were obtained with the uniform cell size distribution. Field emission scanning electron microscopy exposed hexagonal cellular morphology of PMMA/PUU/kaolin 1-5 foams. The PMMA/PUU/kaolin 5 foam with 5wt% clay loading revealed 50% increase in the compression modulus and 21% in the compression strength compared with the neat PMMA/PUU foam. The 10% decomposition temperature of PMMA/PUU/kaolin 1-5 foams was recorded in the range of 512-530?. The foams also showed good water absorption capability. The T-g of PMMA/PUU/kaolin 5 foam (154?) was also higher compared with the PMMA/PUU/kaolin 1 foam (T-g 148?). According to, UL 94 test and limiting oxygen index measurement, the PMMA/PUU/kaolin 1-5 foams achieved higher nonflammability and V-0 rating with the clay addition.