Is ammonium perchlorate in composite solid propellant under strain?

Thermal decomposition of ammonium perchlorate-polystyrene propellant as a function of oxidizer loading has been found to behave in a fashion analogous to the thermal decomposition of ammonium perchlorate as a function of precompression pressure. It has been argued that the above behaviour of the propellant is due to the strain caused by the binder film on ammonium perchlorate contained in the propellant matrix. The presence of strain has been demonstrated independently by X-ray diffraction peak and infrared peak broadening and strain energy measurements