▎ 摘　　要

NOVELTY - A new polyhedral oligomeric silsesquioxane (POSS)-based acryloyloxy hyperbranched polyethylene (Q) is prepared by catalyzing ethylene, palladium-diimine complex (I) as a catalyst, an acrylamide isobutyl silsesquioxane monomer (II) and 4-butanediol diacrylate monomer (III) by one-step chain removal copolymerization mechanism. USE - The new polyethylene (Q) is useful in preparation of graphene/carbon nanotube hybrid electrothermal coating (claimed). ADVANTAGE - The polyethylene (Q) provides coating, which has low square resistance, and excellent high electrothermal temperature and temperature resistance, voltage carrying capacity, heating and cooling rate and bending resistance. DETAILED DESCRIPTION - A new polyhedral oligomeric silsesquioxane (POSS)-based acryloyloxy hyperbranched polyethylene (Q) is prepared by catalyzing ethylene, palladium-diimine complex of formula (I) as a catalyst, an acrylamide isobutyl silsesquioxane monomer of formula (II) and 4-butanediol diacrylate monomer of formula (III) by one-step chain removal copolymerization mechanism. R = isobutyl. An INDEPENDENT CLAIM is included for use of polyethylene (Q) in preparation of graphene/carbon nanotube hybrid electrothermal coating, which involves (1) mixing 0.1-1500 mg/ml graphite powder, polyethylene (Q) and organic solvent (A), ultrasonically sealing the resulting mixture to obtain graphene dispersion (B), centrifuging at low speed, leaving still to obtain graphene dispersion (C) containing excess of polyethylene (Q), centrifuging at high speed and/or vacuum filtering to remove free polyethylene (Q) to obtain dispersion (C), and ultrasonically dispersing in solvent (A) to obtain a graphene dispersion, (2) mixing 0.1-1500 mg/ml carbon nanotube powder, polyethylene (Q) and organic solvent (D), ultrasonically sealing the resulting mixture to obtain carbon nanotube dispersion (E), obtaining carbon nanotube dispersion (F) containing excess polyethylene (Q) by centrifuging at low speed and leaving still, subjecting dispersion (F) to high-speed centrifugation and/or vacuum filtering to remove excess polyethylene (Q), ultrasonically dispersing in organic solvent (D) to obtain a stable dispersed carbon nanotube dispersion, and (3) homogeneously mixing the graphene dispersion, the carbon nanotube dispersion and 0.1-3 mg/ml 2,2-dimethoxy-2-phenylacetophenone, vacuum filtering the mixed liquid using a PTFE filter film with a pore size of 0.1-0.2 μm, naturally volatilizing the solvent in the film layer to obtain a solid film, and curing under a 200-1500 W UV lamp for 3-20 minutes to form a stable electrothermal coating. The mass ratio of polyethylene (Q) to graphite powder is 0.005-10:1. The mass ratio of polyethylene (Q) to carbon nanotubes is 0.005-10:1. The volume ratio of graphene and carbon nanotubes in the graphene dispersion and the carbon nanotube dispersion is 5:1-1:5.