Grafting of telechelic poly(lactic-co-glycolic acid) onto O2 plasma-treated polypropylene flakes

In this work, we described a facile approach to preparing polypropylene (PP) surface functionalized with telechelic poly(lactic-co-glycolic acid) (HO-PLGA-COOH). The PP flakes were first treated with oxygen plasma and then grafted with different molecular weight PLGA (M_w = 50, 100, and 300 K) in dry dichloromethane solution with the addition of phosphorus pentachloride (PCl₅). The attenuated total reflectance-Fourier transform infrared (ATR–FTIR) spectroscopy measurements were used to characterize the composition of the PP surface. The appearance of 1756 cm⁻¹ for carbonyl (CO) stretching and 1090 cm⁻¹ for COC and the morphologies observations by atomic force microscopy show that PLGA graft covered the surface of PP flake. The IR intensity at 1756 cm⁻¹ increases with the decreasing M_w of PLGA, and the molecular weight of PLGA also influence the grafting of PLGA on PP. The contact angle was used to monitor the changes in hydrophilicity of PP flake surface along the treatment procedure. PLGA-grafted PP (PP-g-PLGA) was eventually obtained.