Affiliation:
1. Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou China
2. University of Chinese Academy of Sciences Beijing China
3. School of Safety Science and Emergency Management Wuhan University of Technology Wuhan China
4. Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics Guangzhou China
5. CAS Engineering Laboratory for Special Fine Chemicals Guangzhou China
6. CASH GCC Shaoguan Research Institute of Advanced Materials Nanxiong China
7. New Materials Research Institute of CASCHEM (Chongqing) Co, Ltd Chongqing China
Abstract
AbstractHigh thermal conductivity liquid crystal polymer has become a hot topic in electronic device research. Herein, we introduce a series of thermotropic liquid crystals synthesized by diphenyl diol, m‐phthalic acid, and 5‐hydroxyisophthalic acid. The intermolecular forces are tuned by adjusting the ratio (0, 20%, 40%, 60%, 80%, 100%) of monomers containing hydrogen bond donors in copolymers. The formation and dissociation of hydrogen bonds are analyzed from the red shift and blue shift of infrared spectra at variable temperatures. The thermal conductivity is increased to 0.31 Wm−1 k−1. Meanwhile, its mechanical properties and thermal stability have improved significantly. A sharp increment of 2120% in tensile strength was observed, the maximum tensile strength is 17.39 MPa. While Young's modulus increased from 0.26 to 1.224 GPa. The increase in intermolecular forces is the main reason for this result. Moreover,X‐raysingle‐crystal diffraction, polarizing microscope, differential scanning calorimetry, and thermogravimetric analysis (TGA) were also analyzed to further explore the thermal conduction mechanism. The formation of hydrogen bonds makes the linear polymer chain segments undergo reversible cross‐linking, which affects their crystallization behavior and provides more thermal conduction pathways. By controlling the number of hydrogen bond donors to control the cross‐linking density, the thermal conductivity and mechanical properties can be greatly improved.
Funder
Science and Technology Planning Project of Shenzhen Municipality
Subject
Materials Chemistry,Polymers and Plastics,Surfaces, Coatings and Films,General Chemistry