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In search of new energetic solid solutions. Heat capacity measurements of pure and solid solutions of polyalcoholsĪnd amines are key input to computer modeling of binary phase diagrams usingĬALPHAD method, and further extend these to ternary and quaternary systems PE, NPG and solid solutions of these two polyalcohols, but details were not They also determined thermodynamic properties of 1,1,1-trihydroxymethylpropane. Zhang and Yang reported the heat capacities of an analogous polyalcohol compound, pentaerythritol. Hansen reported details of transitions in pure and binary compounds of Tris and NPG. Īs BCC, with a lattice parameter, a = 8.771 Å at 358 K. High temperature structure of AMPL was determined by Chandra et al. Rose and van Camp and more recently ChandraĪnd Day reported the structure of the α phase of 2-amino-2-methyl-1,3propanediol (AMPL) as monoclinic, P2 1 /n, No. Structure of Tris is BCC, space group Im3m, with a lattice parameter,Ī = 6.876 Å at 423 K. Tris is orthorhombic, space group Pn2 1 a (No. The crystal structure of Tris(Hydroxymethyl)-Aminomethane (Tris) was doneīy Eilerman and Rudman. Structures of amine plasticĬrystals have not been fully investigated. and transforms to high temperature γ phase as FCC structure at 293 K. The low temperature ordered phase of Neopentylalcohol (NPA) hasīeen determined to be triclinic by Salud et al. The high temperature structure of NPG isįCC. Reported by Zannetti and redetermined as monoclinic with space group Low temperature structure of α phase of Neopentylglycol (NPG) was first Group I-4 and high temperature γ phase as FCC by Eilerman et al. The crystal structure of the low temperature Pentaglycerine (PG) α phase has been determined as tetragonal with space Eilerman and Rudman refined the PE structure and determined Refined several times (Llewellyn, Nitta and Shiono ) to be tetragonal (I-4). Heat Capacities of “Plastic Crystal” Solid State Thermal Energy Storage MaterialsĬrystal structure of α-phase of polyalcohols have been investigated extensively, for example structure of Pentaerythritol (PE) has been determined and Temperature (Tf ) and the enthalpy (∆H t ) and entropy (∆S t ) of fusion are (∆H t ) and entropy (∆S t ) of solid-state phase transition, the melting (fusion) In this table, the solid-state phase transition temperature (Tt ), the enthalpy The crystal structures of all γ “Plastic” phases are cubic (Table 1). Low-temperature phase II is referred to as α phase and high-temperature phase Properties of PE, PG, NPG, NPA, Tris and AMPL are listed in Table 1. Crystal structure, transition temperature and thermal properties of polyalcohols (PE, PG, NPG and NPA) and Were initiated for thermal energy storage using Trombe walls in Passive Solar Energy buildings by Benson et al. Of the great potential of energy storage during solid-solid phase transformations, investigations of solid solution for thermal energy storage materials Murrill and Breed first investigated thermal applications of polyalcohol plastic crystals in 1969, in order to evaluate the feasibility of passive temperature control of satellites by using pure polyalcohol,Īmines, and other phase change compounds for space applicatio ns. Amine and polyalcohol plastic crystals, which undergo solid-solid phase changes, are potential candidates for thermal energy Organic molecular crystals that exhibit polymorphic behavior with high enthalpies of solid-solid phase transition and low enthalpy of fusion are classifiedĪs “Plastic Crystals”.

Heat capacityĮquations for α, γ and liquid phases of these six materials are reported. When solid-state phase transition occurs, because of orientational disorder. There is a significant increase in the heat capacity

Phase of the above compounds range between 188 to 294 J/mol K and of the γ phaseīetween 246 and 474 J/mol K. (CH3 )(NH2 )−C−(CH2 OH) 2 ] have also been evaluated. Other amine plastic crystals such as tris(hydroxymethyl)aminomethane and 2-amino-2-methyl-1,3-propanediol [AMPL, Have been measured over a temperature range encompassing solid-solid and The heat capacities of polyalcohol “Plastic Crystals,” such as pentaerythritol, pentaglycerine, neopentylglycol (Received accepted in revised form September 30, 2002) Mail Stop 388, University of Nevada, Reno, Reno NV 89557ĭepartment of Chemistry, University of Nevada, Las Vegas, Las Vegas NV 89154 Metallurgical and Materials Engineering Division, Mackay School of Mines, Heat Capacities of “Plastic Crystal” Solid Stateīy Dhanesh Chandra 1, ∗, Wen-Ming Chien 1, Vinod Gandikotta 1 and  by Oldenbourg Wissenschaftsverlag, München