Effect of Hydrogen,Electron Donor,and Polymerization Temperature on Poly(propylene) Microstructure

Summary: Polypropylene made with an industrial heterogeneous Ziegler-Natta catalyst was characterized using high temperature GPC, ¹³C NMR, and Crystallization Elution Fractionation (CEF). The effect of hydrogen and electron donor during polymerization on poly(propylene) microstructure was investigated at two temperatures. In addition to the expected electron donor effect on polypropylene tacticity, hydrogen was also found to increase polypropylene tacticity. The effect of changing these polymerization conditions on molecular weight and polydispersity was also investigated. Finally, CEF profiles show how the crystallizability of polypropylene increases by adding hydrogen and electron donor to the reactor.