Effects of some nucleating agents on the supercooling of erythritol to be applied as phase change material

Nine nucleating agents, calcium pimelate (CaPi), bicyclic 1, 2, 2]heptane di-carboxylate (HPN-68), a commercially obtained aryl amide nucleating agent (TMB-5), calcium salt of hexahydrophthalic acid (HPN-20E), 1,3:2,4-di-p-methylbenzylidene sorbitol (MDBS) and sodium, potassium, magnesium and calcium salt of benzene-1, 3, 5-tricarboxylic acid (Na₃BTC, K₃BTC, Mg₃BTC₂ and Ca₃BTC₂, respectively), were applied to reduce the supercooling of erythritol, and their effects were investigated by cyclic differential scanning calorimetry (DSC). The results revealed that Na₃BTC and K₃BTC could not induce erythritol to crystallize under the experiment condition. MDBS could only make erythritol to crystallize at a temperature slightly higher than that of pure erythritol, and the effect was unstable. Mg₃BTC₂, Ca₃BTC₂ and HPN-68 could induce erythritol to crystallize at relatively high temperature, but the peak temperature of crystallizing (T _{p, cr}) and the phase change enthalpy of crystallizing (Δ_cr H) decreased greatly as the melting–crystallizing cycles increased. HPN-20E-doped erythritol crystallized at a high temperature with the T _{p, cr} of 69.3 °C at the first cycle, but the T _{p, cr} and Δ_cr H varied greatly during the melting–crystallizing cycles. CaPi and TMB-5 could induce erythritol to crystallize at a stable temperature with the T _{p, cr} of about 69 °C and 64 °C, respectively, and with a stable Δ_cr H of about 204 and 185 J g^?1, respectively, in all melting–crystallizing cycles. Hence, CaPi- and TMB-5-doped erythritol could be used as PCMs and applied in thermal energy storage in which the energy was absorbed at a high temperature and released at a lower but stable temperature.