Apr 9, 2025
5:00pm - 7:00pm
Summit, Level 2, Flex Hall C
Nusrat Chowdhury1,Peng Lan1,Sooyeon Yeon1,David Cahill1
University of Illinois at Urbana-Champaign1
Nusrat Chowdhury1,Peng Lan1,Sooyeon Yeon1,David Cahill1
University of Illinois at Urbana-Champaign1
We explored the range of thermal conductivities that can be obtained by varying the molecular structure and topology of polyester polymers formed from condensation reactions of aromatic acid chlorides (difunctional and trifunctional) with four types of diols (aliphatic and aromatic). We characterized the samples by x-ray scattering, scanning calorimetry, and vibrational spectroscopy; and measured the thermal conductivities by a combination of time-domain thermoreflectance (TDTR) and displacement thermo-optic phase spectroscopy (D-TOPS). The thermal conductivities span a wide range from 0.09 to 0.45 W/(m K). Polyesters with aromatic diol components, e.g., linear 2,6-naphthalenediol (L-dhn), exhibit significantly enhanced thermal conductivity, approximately three times greater than the common polyethylene terephthalate (PET). In contrast, network polyesters with cyclic aliphatic components, such as 4,8-bis(hydroxymethyl) tricyclo [5.2.1.02,6] decane (N-tcddm), show low thermal conductivity (~0.09 W/(m K)) that is nearly a factor of 2 smaller than the thermal conductivity of PET. Temperature-dependent measurements using D-TOPS demonstrate that both 1,4-benzene dimethanol (L-bdm) and L-tcddm polyester maintain a constant thermal conductivity over a broad temperature range (150 K to 360 K), extending up to their respective glass transition temperatures. In addition, we report on the anisotropic thermal conductivity of the liquid crystalline polyester Ekonol, with in-plane and cross-plane thermal conductivities of 1.02 W/(m K) and 0.45 W/(m K), respectively. These findings highlight the significant impact of polymer molecular structure on thermal performance, enabling them to be effective thermal insulators and conductors as required.