A comparative study on anti-UV non-spherical methacrylate polymer particles and anti-UV PVA nanofibers

Three types of anti-UV non-spherical polymer particles (AUNSPP) based on methacrylate and anti-UV PVA nanofiber were synthesized to study and compare their UV protection properties. In the first type of AUNSPP, polystyrene seeds were swollen with dichloromethane solution of 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl) phenol (TINUVIN (R) 234, which hereafter is called TINUVIN), styrene, divinylbenzene, and 2,2'-azobisisobutyronitrile (AIBN). In the other two types of AUNSPP, poly(methyl methacrylate) seeds were swollen with dichloromethane solution of TINUVIN, methyl methacrylate, lauryl methacrylate, ethylene glycol dimethylacrylate, and AIBN. Subsequently, dichloromethane was evaporated from the swollen microspheres, and polymerization was accomplished by elevating the temperature of swollen particles to 70 degrees C. The final particles were assigned as P(S)/TINUVIN, P(S-DVB)/TINUVIN, P(LMA-EGDMA)/TINUVIN, and P(MMA-EGDMA)/TINUVIN composite microspheres. Anti-UV PVA nanofibers were prepared by dispersing P(S-DVB)/TINUVIN microparticles in PVA aqueous solution. Finally, this mixture was electrospun under ambient conditions. Particle size, size distribution, and morphology of the particles were investigated by SEM micrograph and image analyzer software (Image J). The presence of TINUVIN in P(S-DVB)/TINUVIN composite particles was confirmed by FTIR and phosphorescence spectroscopy. The UV protective properties of microcomposite particles and anti-UV nanofibers were studied by UV-Vis spectra of their polyurethane (PU) composite film. Comparatively, similar cutoff wavelength effects were observed in the range of 200-400 nm in all the samples. The obtained results showed consistent drop in the UV-blocking efficiency as the UV irradiation time increased. PU/PS/TINUVIN and PU/anti-UV nanofiber composite films showed the worst and best UV-blocking efficiency, respectively. After 200, 400, 600, 800, and 1000 h of UV irradiation time, the blocking efficiency of the PU-PS/TINUVIN composite films dropped from 80 to 72, 68, 65, and 59 %, and that of the PU/anti-UV nanofiber composite films dropped from 98 to 97, 94, 86, and 83 %.