Six aromatic copolyamides contanining phenyl groups were synthesized and characterized. The concentrations of the para-linked phenyl groups and meta-linked phenyl groups were varied systematically on the copolymers general structure to obtain a set of random copolyamides. Effect of copolymerization on glass transition temperature (Tg), tensile modulus (E), Tensile strength (σ) were measured. Changes in density were determined to estimate the effect on Fractional Free Volume (FFV). Results indicate that the substitution of para-linked phenyl group by meta-linked phenyl group causes an increase in tensile modulus E and tensile strength a decrease in Tg. The observed results are attributed to the asymmetric position of the linkages in the TERE and ISO isomers, because symmetric linkages, such as TERE, induces a higher packing of the polyamide chains while the asymmetry of ISO isomer inhibits packing causing an expansion in the FFV.