Nanocellulose Aerogels for Supporting Iron Catalysts and In Situ Formation of Polyethylene Nanocomposites

摘要: Aerogels of nanocellulose (NC) prepared by freeze-drying cellulose nanofibrils (CNF) hydrogels and followed impregnation with methylaluminoxane serve as nanoporous organic supports for immobilizing single site iron catalysts such bisiminopyridine iron(II) complexes. The resulting catalyst systems, exploiting renewable biomaterials supports, are highly active in low pressure ethylene polymerization. They afford simultaneous control high density polyethylene (HDPE) particle morphology facile NC dispersion within the HDPE matrix. In early stage polymerization, mesoscopic shape replication NC-mediated templating yield platelets containing an core a shell, confirmed scanning electron microscopy (SEM) virgin powders. Opposite to conventionally dried CNF hydrogels, forming large agglomerates, this aerogel-mediated situ NC/HDPE nanocomposite formation is vastly superior melt compounding NC, failing produce fine dispersions. On increasing content 3.0 wt%, both Young's modulus (+50%) tensile strength (+40%) increase at expense elongation break (−80%). According SEM analysis morphology, nanosheets together “shish-kebab” fiber-like structures accounted matrix reinforcement.