Direct Route to Colloidal UHMWPE by Including LLDPE in Solution during Homogeneous Polymerization of Ethylene

Abstract

Experimental methodsMaterials: All manipulations of air and moisture-sensitive compounds are performed under nitrogen or argon atmosphere using standard high-vacuum Schlenk techniques or in a glovebox. Ethylene (grade 3.0) is purchased from BOC, and bis [N-(3-tert-butylsalicylidene) pentafluoroanilinate]titanium (IV) dichloride is obtained from MCat; both are used as received. Toluene (anhydrous 99.8%) and Methylaluminoxane (10 %wt toluene solution) are purchased from SigmaAldrich®.Synthesis: A 1.5 l jacketed Pyrex glass reactor assembled for polymerisation is equipped with a magnetic stirrer, a temperature probe, a gas inlet and a rubber septum for catalyst injection. The oven-dried reactor is purged from air with three vacuum-nitrogen (moistureand oxygen-free) cycles. The desired amount of ethylene-butene copolymer is introduced in the reactor under nitrogen stream and dissolved in the desired amount of toluene at 80ºC for 2 hours prior to cooling to 50°C; this step is skipped for the polymerisation of pure UHMWPE.

Graphene scavenges free radicals to synergistically enhance structural properties in a gamma-irradiated polyethylene composite through enhanced interfacial interactions

“…LLDPE is also envisioned to facilitate the homogeneous polymerization of UHMWPE and the formation of a polymer brush on the folded surfaces of the newly developed polyethylene. 12 Of late, nanoparticles have been frequently investigated for their role in improving the mechanical properties and wear resistance of UHMWPE/LLDPE blends. Park et al 13 reported that UHMWPE/LLDPE-BaTiO 3 nanocomposites exhibited a significant change in mechanical properties.…”

Highly active and thermostable camphyl α‐diimine–nickel(II) catalysts for ethylene polymerization: Effects of N‐aryl substituting groups on catalytic properties and branching structures of polyethylene

“…[ 3 ] Meanwhile, α‐diimine–nickel catalysts also showed their poor thermal stability in the cases mentioned above, which is considered as a drawback of these catalytic systems and likely prevents their use in industrial applications. [ 31–35 ]…”

“…[3] Meanwhile, α-diimine-nickel catalysts also showed their poor thermal stability in the cases mentioned above, which is considered as a drawback of these catalytic systems and likely prevents their use in industrial applications. [31][32][33][34][35] With the goal of improving the thermal stability of the α-diimine-nickel catalysts, various modifications have been made to the α-diimine ligand skeleton (A, Chart 1) by different research groups. [36][37][38][39][40] Compared with 9,10-phenanthrenequinone-, acenaphthoquinone-, and pyrene-4,5-dione-based α-diimine-nickel complexes, the catalysts with hexyl and camphyl-substituted backbones showed better thermal stability and gave PEs with higher molecular weights.…”

Effect of LLDPE on Aging Resistance and Thermal, Mechanical, Morphological Properties of UHMWPE/LLDPE Blends

“…Ultra-high molecular weight polyethylene (UHMWPE) is a thermoplastic polymer that has extremely high molecular weight and offers high impact resistance and toughness, elevated wear strength and fatigue resistance, low coefficient of friction and high environmental stress cracking resistance [1][2][3][4] . Because of its mechanical properties, UHMWPE is widely used in automotive and aircraft ballistic protection, body armor, fishing nets, hip/knee implants, and climbing rope [5][6][7][8] . Even above its melting temperature, UHMWPE still possesses a high melt viscosity, and cannot be processed through the mainstream thermoplastic processing techniques like extrusion and injection molding, the exception of compression molding and ram extrusion 6 which largely restricts its efficiency of mass production.…”