On Study Of Thermodynamic Properties Of Several Materials

The thermodynamic properties of materials can give important guiding to the related research and theory application. This paper has studied the thermodynamic properties of several materials. The results are listed as following:1. Several different morphology of nanometer ZnO particles were prepared with hydrothermal or solvthermal method. Characterizations of the products were conducted by the technologies of XRD, SEM, and TEM. The mole standard enthalpy of formation of the nano-ZnO particles were measured by the synchronous differential scanning calorimetry method, which is a new calorimetry method.The results of the measurements are showed as following: short colume like nano-ZnO:ΔfHm(ZnO(c))=(-352.7±0.4) kJ·mol-1stick like nano-ZnO:ΔfHm(ZnO(s))=(-354.62±0.39) kJ·mol-1wiskle like nano-ZnO:ΔfHm(ZnO(w))=(-352.11±0.5) kJ·mol-1flower-ball like nano-ZnO:ΔfHm(ZnO(b))=(-350.55±0.27) kJ·mol-1The results show all the standard enthalpy of formation of the nano-ZnO prepared are larger then the standard ZnO particles.In addition, the heat capacity of the flower-ball like nano-ZnO(b) is measured from297K to483K. A heat capacity expression are obtained like following: Cp(J·g-1·K-1)＝-0.0566＋0.00334T-3.06444T22. With an online calorimetry method, it showed that there is a strong endothermic process during the ZnO formation and displayed that it will absorb0.38J per gram reaction solutions. And the research online calorimetry gives111.4℃as the lowest formation temperature, which is far lower then the preparation temperature as the refference paper used. It indicates that when setting a hydrothermal reaction temperature, the online calorimetry research can give an important suggestion.3. The mole standard enthalpy of formation of Tris-(8-hydroxyquinoline) Aluminum(Alq3) is measured by the combustion method. The result is ΔfH°m(Alq3,s)=(-631.55±2.92) kJ·mol-1at298.15K.