Systems and methods of electrostatically spraying a treatment solution are disclosed that include electrostatically charging, by a cartridge assembled with a handheld portable electrostatic device, a treatment solution. The handheld portable electrostatic device can include a housing, the cartridge removably disposed in the housing. The cartridge can include a cartridge housing, at least one electrode to electrostatically charge and ionize molecules of the treatment solution of the cartridge, and a nozzle positioned at a distal end of the cartridge housing, the nozzle of the cartridge being configured to deliver the electrostatically charged treatment solution and configured to be in fluid communication with an air supply tube in fluid communication with a pump in the housing.

A device for producing a dyed plastic melt and an undyed plastic melt includes a multi-shaft screw extruder, a first metering installation, a second metering installation, and a control installation, selecting between a first operating mode for producing the dyed plastic melt and a second operating mode for producing the undyed plastic melt. The first metering installation feeds an undyed plastic material through a first infeed opening into a housing of the multi-shaft screw extruder, and the second metering installation feeds at least one dyeing agent through a second infeed opening into the housing. In order for the undyed plastic melt to be produced, the plastic material is fed exclusively via the first infeed opening such that residual dyeing agent which is still located in the second metering installation or in the region of the second infeed opening does not contaminate the undyed plastic melt.

A method of increasing bubble stability of a needful high molecular weight bimodal high-density polyethylene resin in need thereof, the method comprising subjecting the needful high molecular weight bimodal high-density polyethylene resin to a determined amount of oxygen tailoring of the resin so as to independently increase both the resin's melt storage modulus G (at G=3000 pascals) and complex viscosity ratio SH1000, and thereby make an oxygen-tailored high molecular weight bimodal high-density polyethylene resin having a targeted increase in bubble stability. The method uses a tailoring effective amount of molecular oxygen (O.sub.2) to achieve the desired oxygen tailoring. The method uses these advanced rheological properties from dynamic mechanical spectroscopy, but analyzes the data in a different way that is more sensitive to changes in resin composition and properties, and yet achieves a resin regime having a targeted increase in bubble stability.

Systems and methods of electrostatically spraying a treatment solution are disclosed that include electrostatically charging, by a cartridge assembled with a handheld portable electrostatic device, a treatment solution. The handheld portable electrostatic device can include a housing, the cartridge removably disposed in the housing. The cartridge can include a cartridge housing, at least one electrode to electrostatically charge and ionize molecules of the treatment solution of the cartridge, and a nozzle positioned at a distal end of the cartridge housing, the nozzle of the cartridge being configured to deliver the electrostatically charged treatment solution and configured to be in fluid communication with an air supply tube in fluid communication with a pump in the housing.

A method of increasing bubble stability of a needful high molecular weight bimodal high-density polyethylene resin in need thereof, the method comprising subjecting the needful high molecular weight bimodal high-density polyethylene resin to a determined amount of oxygen tailoring of the resin so as to independently increase both the resin's melt storage modulus G (at G=3000 pascals) and complex viscosity ratio SH1000, and thereby make an oxygen-tailored high molecular weight bimodal high-density polyethylene resin having a targeted increase in bubble stability. The method uses a tailoring effective amount of molecular oxygen (O.sub.2) to achieve the desired oxygen tailoring. The method uses these advanced rheological properties from dynamic mechanical spectroscopy, but analyzes the data in a different way that is more sensitive to changes in resin composition and properties, and yet achieves a resin regime having a targeted increase in bubble stability.