Thermogravimetric Analysis of Fiber Reinforced Plastics

摘要

The application of thermochemical analysis techniques to the study of environmental and thermal degradation of fiber reinforced plastics (FRP) materials provides imporatnt information about changes in the molecular structure. Measurements were carried out on E-glass/vinylester and E-glass/polyester, using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The former method shows the relationship between the amount of water absorbed by the material and the extent of matrix depolymerization. Furthermore, the TGA results show that the rate of matrix degradation due to exposure to de-ionized water increases by a factor of 8 upon raising the temperature from 23 deg C to 50 deg C and by a similar factor upon raising it from 50 deg C to 80 deg C, corresponding to an activation energy of about 60-65 kJ. Differential scanning calorimetry measurements on various sections (surface, intermediate region and core) of E-glass/vinylester plate material show that both T_g and #DELTA#C_p values are explained in term of matrix depolymerization of the material during manufacturing and of the fiber content in the various regions, respectively. In general, thermochemical analysis is demonstrated to be very valuable in studying the degradation of polymeric composites.