Organosilicon‐functionalized Polyolefins, a Kind of Designable and Versatile Polymer: from Preparation to Applications

Functionalization of polyolefins has been a challenging but promising issue since their invention, with the promise of retaining inherent properties and overcoming the low reactivity and poor compatibility. Organosilicons are widely used for polymer modification to improve thermal stability, hydrophobicity, compatibility, and permeability. Since the advent of alkoxysilane-grafted polyethylene in 1960s, organosilicon-functionalized polyolefins (Si-PO) have been extensively prepared, investigated, and developed. The structure of Si-PO is designable due to the flexible chemistry of organosilicons; crosslinked, long chain branched, and star-shaped polyolefins are available after the introduction of alkoxysilanes, chlorosilanes, hyrdosilanes, or alkylsilanes into polyolefins, and generally these polymers are more compatible to fillers than commercial polyolefins due to stronger interaction. In addition, functionalization of polyolefins with stable organosilicon components such as polysiloxane and polysilsesquioxane can improve thermostability, hydrophobicity, gas permeability, and aging resistance; such polyolefins are usually grafted or block polymers. In this review, Si-PO is classified according to the functional organosilicon component, namely alkoxysilane, chlorosilane, hydrosilane, alkylsilane, polysiloxane, and polysilsesquioxane; their preparations are discussed minutely and summarized with manifold examples. Silicon-containing structures impart the unique properties of organosilicons to polyolefins; applications of Si-PO as compatibilizers, processing aids, battery separators, and separating membranes have been widely reported and are discussed here.