on the glass transition temperature of cyclic PPA was investigated. After determining the glass transition temperature of pure PPA to be 187 °C, PPA films with various DEA concentrations were prepared. By varying DEA concentration, the authors were able depress Tg to 12.5 °C demonstrating the importance of plasticizers in enhancing the mechanical flexibility and thermal properties of PPA. Similar results were previously observed where the thermal transitions were depressed from 95 °C for cPPA to 24 °C for diethyl phthalate (DEP)-plasticized cPPA. Among the few studies that have been reported on the usage of plasticizers with PPA, it has been noted that the usage of plasticizers results in a decrease in the tensile stress of the polymers which indicate that PPA is becoming more flexible and hence the film can fold more easily. Nevertheless, a control on the amount of plasticizer used is important. For instance, in the study discussed above, it has been reported that the usage of a large amount of plasticizer (more than 50% w/w in comparison with PPA polymer) results in phase segregation and a decrease in the flexibility of the PPA film. Furthermore, the nature of the used solvent can highly affect the mechanical properties of PPA as well. In particular, in another study published in 2019, both the elastic modulus and tensile strength increase when dichloromethane was used as a solvent to drop-cast PPA in comparison to dioxane and chloroform. Thermal properties The thermal stability of PPA is highly dependent on whether the polymer is end-capped or isolated without end groups. Cyclic PPA, in addition to functionalized linear PPA chains are known to be thermally stable for up to 150oC as determined by both Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Moreover, the polymer is known for its long-term shelf life wherein it can be stored at room-temperature for a significant amount of time. Various chemists have studied substitution effects on the thermal stability of PPA. For instance, scientists at The International Business Machines Corporation (IBM) concluded, after extensive studies, that o-phthalaldehyde monomers functionalized with chloro, bromo, and 4-trimethylsilyl functional groups result in highly stable PPA compared to the unsubstituted polymer. Similarly, Phillips et al. proved that the substituted and end-capped poly(4,5-dichlorophthalaldehyde) possesses higher thermal degradation temperatures than its unsubstituted counterparts. Chemical properties By means of controlling the identity and reactivity of the endcaps, PPA can withstand harsh chemical conditions with no