Dynamical simulated annealing for assessing the high performance nature ofpoly(ethersulfone)s

In order to assess the high performance nature of poly(ethersulfone) or to provide an understanding of its molecular origin, stress-strain measurement s were carried out as a function of temperature for neat poly(ethersulfone) as well as its glass- and carbon-reinforced composites. It was observed th at the modulus of these samples has not dramatically changed when changing the temperature; instead, the tensile strength values changed on the expens e of the elongation at break as to keep the modulus constant. Close inspect ion of the molecular-level behavior of the material using molecular simulat ion techniques revealed that the distribution of the dihedral angles around the oxygen and sulfur atoms did not drastically change below the heat defl ection temperature, possibly due to the rigidity of the polymeric chains. H owever, above that temperature the conformational change was evident as the chains exhibited more of the higher energy conformations. Young's modulus predicted for the polymer indicated a good agreement with the experimental observations thus suggesting the validity of the model to describe the real system. Other key elastic constants of the polymer, such as the Poisson va lues, Lame constants and the compressibility were also evaluated.