Tailored Crystalline Order Of Nascent Polyethylene From Metallocene Supported On Confined Polystyrene

Building the desirable superstructure of polyethylene is one of the important topics for developing high valueadded products, which brings potential benefits for society and sustainable development. Crystalline order is the ubiquitous superstructure for enhancing mechanical properties of polymeric materials. In this work, polystyrene copolymers (c-PS) are incorporated into pores of silica through the wet-impregnation procedure of styrene and p-chloromethyl styrene followed by the in-situ free-radical copolymerization. Metallocene catalyst is further immobilized on supported silica. This incorporated c-PS is proved to be coated on the surface of silica pore walls rather than blocking the interparticle channels. The swelling behavior of c-PS inside the pores are performed by pulsed field gradient NMR (PFG-NMR) and thermoporosimetry (TPM-DSC), where a swelling behavior is shown in the toluene owing to the matched solubility parameters between the c-PS and toluene. According to the swelling behavior of c-PS confined in the pores, a compartmentalization is created hindering the formation of chain overlaps and increasing the crystallinity order of nascent polymers. As a result, the nascent polyethylene with a high crystallinity (i.e., bulk crystallinity Xc,DSC = 72.9 % and linear crystallinity Xc, WAXD = 90.5 %) is synthesized. There is a considerable activity (i.e., 3.8 ? 106 g PE?(molZr?h)- 1) at 70 ?C. Finally, the particle morphology of the nascent polyethylene is investigated based on the swelling behavior of c-PS.