Dimethyl biphenyl-3,4’-dicarboxylate (3,4’BB) and dimethyl biphenyl-4,4’-dicarboxylate (4,4’BB) are attractive aromatic diesters that have received considerable research interest in past years as property enhancing monomers or comonomers in thermoplastic polyesters. Recent advances in processes to prepare these biaryl monomers have inspired us to expand early BB containing polyester research to new compositions. Novel poly (ethylene terephthalate) (PET) copolyester thermoplastics were synthesized via melt polycondensations incorporating 3,4’-bibenzoate (3,4’BB) and 4,4’-bibenzoate (4,4’BB) moieties) into the PET backbone. Melting points and glass transition temperatures were measured over a wide composition range for these copolyesters with differential scanning calorimetry. An amorphous window for these compositions was determined from the observed melting points. Significant increase in T<sub>g</sub> was observed as the 4,4’BB or 3,4’BB content in the backbone increased. Dynamic mechanical analysis (DMA) provided information about thermal transitions and sub-T<sub>g</sub> relaxations. Tensile measurements were used to obtain mechanical properties Permeability analysis helped to understand how monomer symmetry affects oxygen diffusivity and solubility in amorphous film samples, and again in biaxially oriented copolyesters containing 4,4’BB monomer.

Copolyesters containing 4,4'-bibenzoate and 3,4’-bibenzoate units

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.