Microencapsulations of n-octadecane with different crosslinked methylmethacrylate-based polymer as shells were carried out by suspension-like polymerizations. 1,4-butylene glycol diacrylate (BDDA), divinylbenzene (DVB), trimethylolpropanetriacrylate (TMPTA) and pentaerythritol tetraacrylate (PETRA) were employed as crosslinking agents. The influences of the type and amount of crosslinking agent, the type of initiator and polymerization temperature on the properties of as-prepared microencapsulated phase change materials (MicroPCMs) have been studied. The MicroPCMs were characterized using Fourier transformed infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Thermal properties and thermal stability of MicroPCMs were investigated by differential scanning calorimetry (DSC) and thermalgravimetric analysis (TGA). Shell mechanical strength was measured by micro/nano-hardness tester. Thermal properties, thermal resistant temperatures as well as shell mechanical strength of MicroPCMs enhanced as the number of crosslinkable functional moieties of the crosslinking agents increased. The MicroPCMs containing 75.3 wt% n-octadecane obtained using PETRA as crosslinking agent has the highest latent heats of melting (156.4 J/g) and crystallization (182.8 J/g) and displays the highest thermal stability and shell mechanical strength. The MicroPCMs prepared with DVB shows a relatively higher shell mechanical strength and heat capacity compared with those prepared with BDDA. Both heat capacity and thermal stability of MicroPCMs prepared by combining 2,2'-azobisisobutyronitrile (AIBN) and redox initiators at 45 degrees C were lower than that of MicroPCMs prepared with AIBN or benzoyl peroxide (BPO) at 85 degrees C. Hence, MicroPCMs with crosslinked methylmethacrylate-based polymer as shells, especially crosslinked polymer shells of higher crosslinking density, show a good potential as a solar-energy storage material. (C) 2011 Elsevier B.V. All rights reserved.