Grafted Polypropylene with Maleic Anhydride and Styrene as a Bulking Agent for Biodegradable Poly(Malonyl Carbonate) Polypropylene

Polypropylene (PP) is one of the most versatile polymers, which is widely used in many fields such as automobile, electronics, packaging, building materials and fiber because of its low cost, high thermal stability, stable chemical properties and good water insolubility. However, PP is a non-polar polymer with low compatibility with other polar materials, and improving its compatibility with other plastics has become a hot spot for current research.

In this paper, polypropylene containing maleic anhydride and styrene (MAH-g) was prepared by melt grafting method. The results of Fourier transform infrared spectroscopy showed that the maleic anhydride in the form of cyclic anhydride was successfully grafted onto the polypropylene backbone. The effects of different PP-g-(MAH-co-St) contents and grafting ratios on the structure and properties of poly(propylene carbonate)/polypropylene sheets were investigated. The results of Fourier transform infrared spectroscopy and scanning electron microscopy indicated that ring-opening reactions occurred between PP-g-(MAH-co-St) and the anhydride functional groups of poly(propylene carbonate). The ring-opening reaction, chemical bonding, co-crystallization, increased interfacial adhesion and decreased interfacial tension may be the mechanism of PP-g-(MAH-co-St) as a bulking agent for poly(propylene carbonate)/polypropylene flakes.

The MPC-g-(MAHco-St) content of PPC/PP flakes and PPC flakes with high tensile strength and low MFRs were able to be successfully grafted onto the main chain of PP in the form of cyclic anhydride. The poly(propylene carbonate)/PP chips had good compatibility, tensile properties, thermal stability and degradability, and the addition of PP-g-(MAH-co-St) reduced its melt flow rate.

Figure 1 The infrared spectra of PP-g (MAH-Co-St) and PPC / PP-g (MAH-Co-St)

Figure 2 SEM PPC / PP section: (a) PPC / PP (80 / 20), (b) PPC / PP (80 / 20), (c) PPC / PP (GMAH) (GMAH=0.94%) / (b) (2080 / 20, (d) PPC (GMAH) (GMAH=0.94%), (e) (GMAH) (GMAH=1.51%) / 80 / 8 / 20), (f) (GMAH=1.51%) / PP (PP (80 / 8 / 20)