Modification of poly (butylene terephthalate) with core-shell nanoparticles containing UV-absorber

A type of core-shell polymer nanoparticles capable of UV-stabilizing and toughening, was synthesized via the two-step emulsion polymerization of butyl acrylate (BA), methyl methacrylate (MMA) and glycidyl methacrylate (GMA), in the presence of 2-hydroxy-4-(3-methacryloxy-2-hydroxyl-proroxy) benzophenone (BPMA) as UV-stabilizing agent. Fourier transformed infrared (FTIR) analysis indicated that BPMA was successfully incorporated into the nanoparticles. The microstructures and microphases were investigated by transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) and the results showed that the particles with an average diameter about 80 nm exhibited a core-shell structure and had a low glass transition temperature around −42 °C and a high glass transition temperature around 107 °C. UV–Vis absorption spectroscopy analysis revealed that poly (BA-MMA-BPMA-GMA) nanoparticles maintained almost the same UV-absorbing ability as 2, 4-Dihydroxybenzophenone (UV-0). Moreover, poly (BA-MMA-BPMA-GMA) was well dispersed in the poly (butylene terephthalate) (PBT) matrix as studied by scanning electron microscope (SEM). The mechanical properties before and after UV-irradiation illustrated that both of the UV-stability and toughness of PBT were remarkably improved by the core-shell nanoparticles simultaneously. In addition, thermogravimetry analysis (TGA) showed that PBT/poly (BA-MMA-BPMA-GMA) had better thermal stability than PBT/poly (BA-MMA-GMA)/UV-0 system and the UV-degradation degree of PBT was greatly retarded by poly (BA-MMA-BPMA-GMA).