Effect of nanopowders (TiO_2 and MMT) and aramid honeycomb core on ablative, thermal and dynamic mechanical properties of epoxy composites

摘要

The present work investigates the ablative, thermal and dynamic mechanical properties of epoxy resin modified with nano-titanium dioxide and organomodified monmorillonite. The composites properties with aramid honeycomb core as stiffness reinforcement were compared with those without honeycomb. Samples have been subjected to combustions gases at a temperature above 1900 degrees C during 120 s. The best thermal protective properties, i.e. the lowest: temperature of the rear surface area and ablative weight loss were exhibited by the composites containing 3.75% of oMMT and 1.25% of TiO2 with aramid honeycomb core. Dynamic mechanical thermal analyser measurements were carried out on an Instrument DMA SDTA861. The tests were performed by using a compression deformation mode in the temperature range from 20 degrees C to 140 degrees C. The glass transition temperature (T-g) was determined from the position of the maximum value of tan delta. This temperature reached values from about 74 degrees C (with tan delta = 0.59) to 79 degrees C (for tan delta = 0.66). The highest values of the complex modulus M* were in the range from 70 MPa to 465 MPa, for all phase compositions, but at temperature of 140 degrees C the complex modulus M* had much lower values in the range of 20-25 MPa.