Preparation of Nonlinear Structure Poly(glycolic acid) with High Toughness, Excellent Hydrolysis Stability, and Foaming Performance

Abstract

Poor toughness and fast hydrolysis degradation are the key barriers for poly(glycolic acid) (PGA) toward broader applications. Herein, nonlinear structure PGA with high toughness and excellent hydrolysis stability was prepared through graft and chain extending reaction in the presence of bis(tert-butylperoxyisopropyl)benzene (BIPB) and glycidyl methacrylate (GMA). The rheological behavior, the gel content, and the GPC result demonstrated that GMA was grafted onto PGA chains, and then the epoxy group of grafted GMA reacted with the end groups of PGA, which resulted in the formation of a nonlinear structure in which one original PGA chain connected to the other PGA backbone. The PGA/1.0BIPB/1.0GMA which had the highest nonlinear degree was obtained when the amounts of BIPB and GMA were all 1.0 wt % with respect to PGA, and it showed some excellent characterization. Compared to that of virgin PGA, the elongation at break and impact strength of PGA/1.0BIPB/1.0GMA increased by 547 and 18%, respectively. Moreover, PGA/1.0BIPB/1.0GMA also possessed a faster crystallization rate. The hydrolysis results showed that the tensile strength of PGA/1.0BIPB/1.0GMA decreased by half on the 12th day, delaying by 7 days compared with that of virgin PGA. Furthermore, PGA/1.0BIPB/1.0GMA also had better foaming ability of a 24.68-fold volume expansion ratio. Thus, this work paved a new strategy to design nonlinear structure PGA with high toughness, excellent hydrolysis stability, and ultrahigh foamability.