This study is focused on the thermal stability and the thermal degradation kinetics of two poly(vinyl ethers), PVEs, with different side groups. The objective was to determine how the nature of the side group affects the thermal properties of these materials. Poly(2–Phthalimide Ethyl Vinyl Ether), PPEVE, was derived via zirconocene–mediated cationic homopolymerization, and poly(2–Amino Ethyl Vinyl Ether), PAEVE, was obtained by hydrazinolysis of PPEVE. The thermal stability was investigated employing thermogravimetric analysis, TGA, and differential thermogravimetry, DTG, at six different heating rates. The thermal decomposition kinetics data were analyzed using the Ozawa–Flynn–Wall, OFW, and Kissinger–Akahira–Sunose, KAS, “model–free” methods to calculate the activation energies, \(Ea\), and subsequently the appropriate mathematical model or mechanism to describe the Thermal Decomposition process for each individual homopolymer.