Interface Stability Behaviors of Methanol-Melamine-Formaldehyde Shell MicroPCMs/Epoxy Matrix Composites

Microcapsules containing phase change materials (microPCMs) have been widely applied in smart temperature-controlling materials. Interface stability plays a key role in these microPCMs/matrix composites. The aim of this study was to investigate the interface stability behaviors of methanol-melamine-formaldehyde (MMF) shell microPCMs containing paraffin/epoxy matrix composites. MMF prepolymer can be applied to fabricated microcapsules with smooth shells. The average diameter of the microPCMs could be controlled in the range of 5-45 mu m by stirring speed of 500-6,000 r min(-1). From the SEM morphologies of the interphase between the microPCMs and the epoxy-matrix, it is concluded that the interaction may be enhanced by MMF graft structure due to the increasing of molecular interaction in the interface. During a repeated heat-transmission process, not only the repeated-times of thermal absorbing-releasing process will damage the interface bonding, but also higher thermal conductive speed will make the interface bearing more debonding stress. Large microPCMs in matrix may supply better interface stability. Moreover, the numerical and experimental results are consistent to obtain a clear insight into the rule of interface debonding for microPCMs/matrix composites that the interface perfection can be enhanced by increasing the thickness of interphase. POLYM. COMPOS., 32:810-820, 2011. (c) 2011 Society of Plastics Engineers