Efficient Chemical Synthesis of New Thermoplastic Fluorinated Aromatic Polyester

Recently, great interest has been in synthesizing polymers containing fluorine atoms. Fluorinated polymers exhibit high hydrophobicity, low surface energy, good thermal stability, excellent dielectric properties, low water absorption, and good chemical resistance. This work illustrates the synthesis, characterization, and properties of a new fluorinated aromatic polyester. Poly(fluoromandelic acid) (PFMA). PFMA is a new polymer with multiple fluorine atoms on the polymer chain. Simple heating of 4-fluoromandelic acid, without a solvent or a catalyst, under controlled conditions leads to poly(fluoromandelic acid). The reaction runs in the solid state by the elimination of water. The structure of the resulting poly(fluoromandelic acid) consists mainly of a polyester backbone decorated with p-fluorophenyl groups and has carboxyl and hydroxyl groups at the ends of the polymer chain. Mass spectrometry, solid-state 13C nuclear magnetic resonance (13C ss-NMR), liquid NMR, Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy elucidated the polymer chain structure. The thermal stability of the polymer was also studied, and the melting point was determined from the differential scanning calorimetry. In the case of poly(fluoromandelic acid), the thermal conductivities and diffusivity were measured by the transient plane source (TPS) technique, also referred to as the Hot Disk method. The thermal conductivity measured at different temperatures will also be discussed in relation to the structure of the analyzed polymer as correlated with the crystallinity of the polymer structure determined by XRD diffraction. It was also shown that the new fluorinated aromatic polyester exhibited remarkable hydrophobicity.