A polyethylene composition having the following features: 1) density from 0.945 to 0.950 g/cm 3, determined according to ISO 1183 at 23°C; 2) ratio MIF/MIP from 25 to 43, where MIF is the melt flow index at 190°C with a load of 21.60 kg, and MIP is the melt flow index at 190°C with a load of 5 kg, both determined according to ISO 1133; 3) MIF from 3.5 to less than 8.5 g/10 min.; 4) HMWcopo index from 1 to 40; 5) long-chain branching index, LCBI, equal to or greater than 0.83; wherein the HMWcopo index is determined according to the following formula: HMWcopo = η 0.02 × t maxDSC / 10 ∧ 5 where η 0.02 is the complex viscosity of the melt in Pa.s, measured at a temperature of 190°C, in a parallel-plate rheometer under dynamic oscillatory shear mode with an applied angular frequency of 0.02 rad/s; the t maxDSC is the time in minutes required to reach the maximum value of heat flow (in mW) of crystallization at a temperature of 124 °C under quiescent conditions, measured in isothermal mode in a differential scanning calorimetry apparatus, DSC; LCBI is the ratio of the measured mean-square radius of gyration R g, measured by GPC-MALLS, to the mean-square radius of gyration for a linear PE having the same molecular weight at a mol. weight of 1,000,000 g/mol, said composition comprising: A) 30 ― 70% by weight of an ethylene homopolymer or copolymer (the homopolymer being preferred) with density equal to or greater than 0.960 g/cm 3 and melt flow index MIE at 190°C with a load of 2.16 kg, according to ISO 1133, of 50 to 85 g/10 min.; B) 30 ― 70% by weight of an ethylene copolymer having a MIE value lower than the MIE value of A). 1) density from 0.945 to 0.950 g/cm 3, determined according to ISO 1183 at 23°C; 2) ratio MIF/MIP from 25 to 43, where MIF is the melt flow index at 190°C with a load of 21.60 kg, and MIP is the melt flow index at 190°C with a load of 5 kg, both determined according to ISO 1133; 3) MIF from 3.5 to less than 8.5 g/10 min.; 4) HMWcopo index from 1 to 40; 5) long-chain branching index, LCBI, equal to or greater than 0.83; wherein the HMWcopo index is determined according to the following formula: HMWcopo = η 0.02 × t maxDSC / 10 ∧ 5 where η 0.02 is the complex viscosity of the melt in Pa.s, measured at a temperature of 190°C, in a parallel-plate rheometer under dynamic oscillatory shear mode with an applied angular frequency of 0.02 rad/s; the t maxDSC is the time in minutes required to reach the maximum value of heat flow (in mW) of crystallization at a temperature of 124 °C under quiescent conditions, measured in isothermal mode in a differential scanning calorimetry apparatus, DSC; LCBI is the ratio of the measured mean-square radius of gyration R g, measured by GPC-MALLS, to the mean-square radius of gyration for a linear PE having the same molecular weight at a mol. weight of 1,000,000 g/mol, said composition comprising: A) 30 ― 70% by weight of an ethylene homopolymer or copolymer (the homopolymer being preferred) with density equal to or greater than 0.960 g/cm 3 and melt flow index MIE at 190°C with a load of 2.16 kg, according to ISO 1133, of 50 to 85 g/10 min.; B) 30 ― 70% by weight of an ethylene copolymer having a MIE value lower than the MIE value of A). wherein the HMWcopo index is determined according to the following formula: HMWcopo = η 0.02 × t maxDSC / 10 ∧ 5 where η 0.02 is the complex viscosity of the melt in Pa.s, measured at a temperature of 190°C, in a parallel-plate rheometer under dynamic oscillatory shear mode with an applied angular frequency of 0.02 rad/s; the t maxDSC is the time in minutes required to reach the maximum value of heat flow (in mW) of crystallization at a temperature of 124 °C under quiescent conditions, measured in isothermal mode in a differential scanning calorimetry apparatus, DSC; LCBI is the ratio of the measured mean-square radius of gyration R g, measured by GPC-MALLS, to the mean-square radius of gyration for a linear PE having the same molecular weight at a mol. weight of 1,000,000 g/mol, said composition comprising: A) 30 ― 70% by weight of an ethylene homopolymer or copolymer (the homopolymer being preferred) with density equal to or greater than 0.960 g/cm 3 and melt flow index MIE at 190°C with a load of 2.16 kg, according to ISO 1133, of 50 to 85 g/10 min.; B) 30 ― 70% by weight of an ethylene copolymer having a MIE value lower than the MIE value of A). A) 30 ― 70% by weight of an ethylene homopolymer or copolymer (the homopolymer being preferred) with density equal to or greater than 0.960 g/cm 3 and melt flow index MIE at 190°C with a load of 2.16 kg, according to ISO 1133, of 50 to 85 g/10 min.; B) 30 ― 70% by weight of an ethylene copolymer having a MIE value lower than the MIE value of A).