Loading the polyol carbonization agent into clay nanotubes for the preparation of environmentally stable UV-cured epoxy materials

The halloysite nanotubes (HNTs) were loaded with pentaerythritol (PER). The as-prepared composite (HNT-P) and ammonium polyphosphate (APP) was subsequently added to the UV-curable epoxy resins, giving a new flame-resistant system. Loading of the hydrophilic PER into HNT can reduce the moisture absorption in the UV-curable epoxy resins. The flame retardancy was evaluated by means of the cone calorimeter and limit oxygen index test. The results showed that the flame retardancy of the modified epoxy resin was greatly improved with an obvious decrease in both the heat release and smoke release. Moreover, it was revealed that HNT could catalyze the reaction of APP and PER, and the burning surface of the epoxy resin should be covered by the polyphosphoric-HNT intumescent char layer. We have measured the moisture sorption and dynamic mechanical properties of the UV-cured epoxy resins. As compared to the use of the simple mixture of PER and HNT, the use of the HNT-P nearly kept the storage modulus at about 1809 Mpa and reduced the moisture absorption by 58.2 wt % at 40 degrees C. The results proved that the addition of the HNT-P obtained lower moisture absorption and higher stability of the mechanical properties than adding the simple mixture. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45045.