Intrinsic high thermal conductive co-polyester based on offset π-π stacking

It has been known that phonon mean free path along polymer chains is much larger than in transverse directions because weak interaction between polymer chains leads to chain distortion and entanglement. In order to improve intensity of intermolecular interaction, a series of co-polyesters (CPE) containing different content of offset pi-pi stacking structure in side chains were synthesized by means of polycondensation and transesterification in this work. WAXD patterns unfolded diffraction peak at 2 theta of 27.6 degrees, standing for structure of offset pi-pi stacking. On enlarging intensity of offset pi-pi stacking interaction, specific heat capacity of CPE increased from 1.140 Jg(-1)K(-1) to 1.410 Jg(-1)K(-1) and thermal diffusivity rose from 0.194mm(2)s (-1) to 0.245mm(2)s( -1) . As a result, CPE sample exhibited excellent thermal conductivity (TC) of 0.381 Wm(-1)K(-1) , which is around twice that of traditional thermoplastics. Hence offset pi-pi stacking interaction could strengthen capacity of heat absorption and thermal conduction at the same time, which might be a good candidate for enhancing thermal conductivity of intrinsic polymers. Furthermore, strong pi-pi interaction in side chains could maintain modulus when temperature is over glass temperature. And the Young modulus grew from 0.14 GPa to 0.44 GPa with the augment of offset pi-pi stacking structure.