Thermal degradation behavior of liquid crystalline thermoset with MgO

18^th International Conference and Exhibition on Materials Science and Engineering

May 28-30, 2018 Osaka, Japan

Bongsoo Lee and Seunghyun Cho

Chung-Ang University, South Korea
Soongsil University, South Korea

Posters & Accepted Abstracts: J Material Sci Eng

Abstract :

A weighed amount of diglycidyl ether of 4, 4-bisphenol (DGEBP) was placed in the 170 �°C convection oven to be melted. Once sample was melted, a stoichiometric amount of sulfanilamide (SAA) was added to the melt. To fabricate composites, DGEBP were melt-blended with the filler, MgO. The mixture was cured for 4 hours at 180 �°C. The liquid crystalline phase change of DGEBP was investigated by POM and DSC. The dispersion of filler was investigated by FE-SEM and EDS. The thermal stability of composites was investigated by thermogravimetric analysis (TGA) over the temperature range of 25 to 1000 �°C. The heating rates were used to calculate the activation energies for thermal decomposition under nitrogen were 5, 10, 20 and 40 �°C/min. The activation energies of thermal degradation were calculated by Flynn-Wall method and Kissinger method, respectively. Activation energies for decomposition (Ed) of DGEBP-SAA-MgO composite system were calculated as follows. It is an integral method which allows determination of Ed as a function of conversion �± by a weight loss process as follows, ln q=C-(Ed/R) (1/T) where Ed is the overall activation energy for weight loss measured at conversion �±, q is the heating rate, C is a constant, R is the gas constant and T is the absolute temperature where conversion �± is reached at heating rate q. The conversion was calculated as the ratio of actual weight loss to total loss corresponding to a given stage of the degradation process as follows, �±=(Mo-Mt)/(Mo-Mâ��) where Mo is the initial mass, Mt is the mass at time t and Mâ�� is the residual mass after completion of weight loss process. The activation energies for DGEBP-SAA-MgO system calculated by slopes of plots of Flynn-Wall method and Kissinger method are compared in Table 1. bslee@cau.ac.kr, scho@ssu.ac.kr