A composite article is comprised of coal dust, as defined herein, and a polymer derived ceramic material that is pyrolyzed in a substantially non-oxidizing atmosphere. For example, the composite article may be made of a mixture of the coal dust and polymer derived ceramic, from particles formed of a mixture of coal dust and polymer derived ceramic or from complex particle composites comprising a plurality of particles formed of a mixture of coal dust and polymer derived ceramic.

A composite article is comprised of coal dust, as defined herein, and a polymer derived ceramic material that is pyrolyzed in a substantially non-oxidizing atmosphere. For example, the composite article may be made of a mixture of the coal dust and polymer derived ceramic, from particles formed of a mixture of coal dust and polymer derived ceramic or from complex particle composites comprising a plurality of particles formed of a mixture of coal dust and polymer derived ceramic.

A system for controlling the temperature of a film before and/or during application, the system including: a heat source for heating a film; and stretch rollers; wherein the heat source heats the film from an ambient temperature to a temperature from about 2° C. to about 40° C. above the ambient temperature, wherein the film is heated prior to or simultaneous to being stretched by the stretch rollers, and wherein the ambient temperature is below 15° C. A system for improving the application of film by transfer of electrostatic charge is also described. The preheating system and/or electrostatic charge system may be used to enhance binding and sealing properties of stretch films used for wrapping palletized products in a reduced temperature environment. Other embodiments of the preheating film system and electrostatic charge system, and methods for their use, are described herein.

Methods and systems are provided for heating a dielectric preform material. An exemplary method includes inserting the preform material into a microwave cavity along a longitudinal axis of the microwave cavity and supplying the microwave cavity with microwave power having a frequency that corresponds to an axial wavelength along the longitudinal axis of the microwave cavity. The axial wavelength is greater than a length of the preform material along the longitudinal axis. The method includes heating the preform material within the microwave cavity by the microwave power and determining temperatures of the preform material at one or more locations on a surface of the preform material. The method further includes adjusting, based on the temperatures of the preform material, the microwave frequency to achieve substantially uniform heating at least on a sidewall of the preform material along the longitudinal axis.

Methods and systems are provided for heating a dielectric preform material. An exemplary method includes inserting the preform material into a microwave cavity along a longitudinal axis of the microwave cavity and supplying the microwave cavity with microwave power having a frequency that corresponds to an axial wavelength along the longitudinal axis of the microwave cavity. The axial wavelength is greater than a length of the preform material along the longitudinal axis. The method includes heating the preform material within the microwave cavity by the microwave power and determining temperatures of the preform material at one or more locations on a surface of the preform material. The method further includes adjusting, based on the temperatures of the preform material, the microwave frequency to achieve substantially uniform heating at least on a sidewall of the preform material along the longitudinal axis.

Illustrative examples of forming and using suitably adapted material in an additive manufacturing process includes operations of: exposing a first polymer sheet to a first plasma, such that an amine-functionalized sheet surface is formed; exposing a second polymer sheet to a second plasma, such that an epoxide-functionalized sheet surface is formed; and combining the amine-functionalized sheet and the epoxide-functionalized sheet, such that the amine-functionalized sheet surface contacts the epoxide-functionalized sheet surface. The workpiece is subsequently heated to form a structure, where heating of the workpiece causes covalent chemical bonds to form between the plasma-treated first polymer sheet and the plasma-treaded second polymer sheet.

Illustrative examples of forming and using suitably adapted material in an additive manufacturing process includes operations of: exposing a first polymer sheet to a first plasma, such that an amine-functionalized sheet surface is formed; exposing a second polymer sheet to a second plasma, such that an epoxide-functionalized sheet surface is formed; and combining the amine-functionalized sheet and the epoxide-functionalized sheet, such that the amine-functionalized sheet surface contacts the epoxide-functionalized sheet surface. The workpiece is subsequently heated to form a structure, where heating of the workpiece causes covalent chemical bonds to form between the plasma-treated first polymer sheet and the plasma-treaded second polymer sheet.

A system for controlling the temperature of a film before and/or during application, the system including: a heat source for heating a film; and stretch rollers; wherein the heat source heats the film from an ambient temperature to a temperature from about 2 C. to about 40 C. above the ambient temperature, wherein the film is heated prior to or simultaneous to being stretched by the stretch rollers, and wherein the ambient temperature is below 15 C. A system for improving the application of film by transfer of electrostatic charge is also described. The preheating system and/or electrostatic charge system may be used to enhance binding and sealing properties of stretch films used for wrapping palletized products in a reduced temperature environment. Other embodiments of the preheating film system and electrostatic charge system, and methods for their use, are described herein.

A method for the polycondensation of recycled PET includes the steps of introducing a mass of recycled PET in a reaction chamber, applying heat to the mass of recycled PET introduced in the reaction chamber in order to reach a working temperature and maintain it for a treatment time, and moving the mass of recycled PET during at least part of the heat application step. The method further includes the step of applying vacuum to the reaction chamber during at least part of the heat application step. The heat application occurs by dielectric microwave heating of the mass of recycled PET.

A method for the polycondensation of recycled PET includes the steps of introducing a mass of recycled PET in a reaction chamber, applying heat to the mass of recycled PET introduced in the reaction chamber in order to reach a working temperature and maintain it for a treatment time, and moving the mass of recycled PET during at least part of the heat application step. The method further includes the step of applying vacuum to the reaction chamber during at least part of the heat application step. The heat application occurs by dielectric microwave heating of the mass of recycled PET.