Investigation on thermo-stabilization effect and nonisothermal degradation kinetics of the new compound additives on polyoxymethylene

An increase in the thermal stability of several new additives on polyoxymethylene (POM) was attempted via thermogravimetric analysis (TGA) (static state) and balance torque testing (dynamic state), which truly reflected the processing in practice. The thermal stability of POM was improved by adding some of additives actually, especially for the compound stabilizer with oxidized polyethylene wax (OPE), low molecular weight polyamide 6 (LMWPA6) and triphenyl phosphate (TPP) from the static and dynamic data. Furthermore, the kinetic parameters for compound stabilizers of POM degradation were calculated from thermogravimetry (TG) curves by Coats-Redfernd method. The results reveal that the degradation temperatures of POM can be obviously raised by compound stabilizers OPE/LMWPA6/TPP. The long-term thermo-stability test of POM shows that POM with stabilizing system above has no obvious decrease in impact strength after storage duration of 15 days in an oven at 140 °C.