UV Absorber
The UV absorbers dissipate the absorbed light energy from UV rays as heat by reversible intramolecular proton transfer. This reduces the absorption of UV rays by the polymer matrix and hence reduces the rate of weathering. Typical UV-absorbers are oxanilides for polyamides, benzophenones for PVC, benzotriazoles and hydroxyphenyltriazines for polycarbonate.
Strongly light-absorbing PPS is difficult to stabilize. Even antioxidants fail in this polymer since the polymer is electron-rich and behaves as antioxidant. The acids or bases in the PPS matrix can disrupt the performance of the conventional UV absorbers such as HPBT. PTHPBT which is modification of HPBT are shown to be effective even in these conditions.
Read more about this topic: Stabilizers For Polymers