Radiation‐induced grafting of pentamethyl hindered amine light stabilizer 1,2,2,6,6‐pentamethyl‐4‐piperidinyl methacrylate onto polypropylene

Abstract

ABSTRACT:The ␥-radiation-induced grafting of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate (PMPM) onto polypropylene (PP) was investigated with a simultaneous irradiation technique. The effects of the solvent, dose, monomer concentration, and photoinitiator on the grafting were investigated. The grafting was easier in a benzene solution than in chloroform and acetone solutions. The grafting percentage first increased almost linearly with the irradiation dose until 20 kGy and then increased slowly or remained constant. The grafting percentage increased with the monomer concentration until 1.1 mol/L. The grafting percentage was higher when the proper amount of benzophenone was added. The grafted samples were characterized with Fourier transform infrared spectroscopy and thermogravimetric analysis. Carbonyl groups were found on grafted PP samples, and the carbonyl index increased with the grafting percentage. Thermogravimetric analyses proved the existence of grafted materials on PP, and grafted PMPM thermally decomposed at a lower temperature than PP. The radiation resistance of PP with grafted PMPM was better than that of pristine PP.

Synthesis and photostabilizing performance of a polymeric HALS based on 1,2,2,6,6-pentamethylpiperidine and vinyl acetate

“…The APP/VAc copolymer was characterized by 13 C NMR and its spectrum is shown in Figure 1. The signals at 170.3 ppm and 174.2 ppm are due to the carbonyl carbons.…”

“…The synthesis of HALS of higher molecular weight by addition or condensation copolymerizations [9][10][11] or the grafting of photostabilizers onto the preformed polymer [12][13][14][15][16] are usual strategies described by the literature to eliminate or minimize such undesirable effects. The preparation of polymeric HALS by the copolymerization of hindered amines with ethylene or propylene is also an alternative route to reduce their physical loss [17,18] .…”

“…The APP was prepared by two different routes involving the alkylation and functionalization of 2,2,6,6-tetramethyl-4-piperinol. The APP and intermediate compounds generated during the conversion of the piperidinol structure were characterized by FTIR and 13 C NMR. Subsequently a new polymeric HALS was synthesized via the radical copolymerization of APP with VAc and characterized by FTIR, 13 C NMR and SEC and its photostabilizing effectiveness was evaluated in PP films.…”