Synthesis and characterization of HALS/UV-absorbers bifunctionalized core-shell elastomer and Its application in polyoxymethylene

Abstract

Poly(BA-MMA-PMPA-BPMA), a core-shell polyacrylate elastomer containing hindered amine light stabilizer (HALS) and benzophenone UV-absorber (UVA) in the shell phase, was prepared by two-stage seeded emulsion polymerization from n-butyl acrylate (BA), methyl methacrylate (MMA), 1,2,2,6,6-pentamethylpiperidin-4-ylacrylate (PMPA) and 2-hydroxy-4-(3-methacryloxy-2-hydroxyl-proroxy) benzophenone (BPMA). Poly(BA-MMA-PMPA-BPMA) was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H-NMR), transmission electron microscopy(TEM), differential scanning calorimetry(DSC), thermogravimetric analysis (TG) and UV-visible (UV-vis) absorption spectroscopy. Furthermore, the obtained Poly(BA-MMA-PMPA-BPMA) was melt-blended with polyoxymethylene (POM). The effect of Poly(BA-MMA-PMPA-BPMA) on POM was compared with that of Poly (BA-MMA-PMPA) and Poly(BA-MMA-BPMA). Scanning electron microscope (SEM), metallographic microscopy, DSC and mechanical properties were employed to characterize POM blends before and after UV irradiation. The results showed that the size of surface cracks and changing degree of melting point of POM/poly(BA-MMA-PMPA-BPMA) were lower than that of POM/poly(BA-MMA-PMPA) and POM/poly(BA-MMA-BPMA). The percentage retention of elongation at break and notched impact strength of POM/poly(BA-MMA-PMPA-BPMA) was 63 % and 80 % respectively after 800 h UV irradiation, which was higher than that of POM/poly(BA-MMA-PMPA) and POM/poly(BA-MMA-BPMA). Therefore, it could conclude that the photostabilizing of Poly(BA-MMA-PMPA-PBMB) was greatly enhanced, attributing to the synergistic effect between HALS and UVA.