Abstract:
Disclosed is a solid state foaming method for the creation of nanofoams (about or less than 100 nm) by saturating thermoplastic polymers with liquid carbon dioxide, optionally, at low saturation temperatures of below room temperature and lower.
Abstract:
A method for generating a microstructure that includes microcellular bubbles, in a material that includes molecules of a thermoplastic polymer, comprises: determining a size-index for the material that represents an average size of the thermoplastic polymer molecules included in the material, and in response to the determined size-index, setting a parameter of a process to generate a microstructure in the material that includes microcellular bubbles. The process to generate a microstructure in the material includes: 1) infusing into the material, during a first period, a gas that does not react with the material, 2) making the gas-infused material thermodynamically unstable.
Abstract:
The present disclosure describes devices capable of continually and controllably passing a polymer film or fiber through a pressurized vessel, while maintaining a desired pressure inside the vessel. In certain embodiments, the devices of the present disclosure include dynamic seals capable of limiting the gas flow from the pressurized vessel to lower pressure environments.
Abstract:
A method for creating a foam from a solid thermoplastic material is disclosed. The method includes heating a solid, noncellular thermoplastic material to a temperature greater than the material's glass transition temperature, and below the melting temperature, and then allowing the material to cool; after the material has cooled, saturating the cooled thermoplastic material with a non-reacting gas to provide a gas-saturated material; and heating the gas-saturated material below the melting temperature of the material so that the material remains a solid, and causes nucleation of bubbles, and creation of cells in the material.
Abstract:
A method for making a flat polymer foam having a core layer of nano-sized open, interconnected cells that includes saturating a solid-state polymer with a supercritical fluid, allowing the gas to desorb for at least 35 minutes, and then heating the gas-saturated solid polymer for at least 3 minutes while constraining the foam in the thickness dimension. Any skin layer formed on the exterior may be removed via polishing, thus creating a foam with an open structure from side to side. The foam can be used as a battery separator.
Abstract:
Methods for saturating a plurality of parisons simultaneously with a saturating gas are disclosed. The parisons may be saturated using a sealed elongated tube through which the parisons are transferred. Parisons may be stacked vertically or horizontally using modular trays, and then loaded into pressure vessels. Parisons may be saturated in individual pressure vessels which are re-pressurized at various intervals. The gas-saturated parisons can be re-heated and blow molded to provide cellular blow-molded articles.
Abstract:
A method for making a flat polymer foam having a core layer of nano-sized open, interconnected cells that includes saturating a solid-state polymer with a supercritical fluid, allowing the gas to desorb for at least 35 minutes, and then heating the gas-saturated solid polymer for at least 3 minutes while constraining the foam in the thickness dimension. Any skin layer formed on the exterior may be removed via polishing, thus creating a foam with an open structure from side to side. The foam can be used as a battery separator.
Abstract:
The present disclosure describes devices capable of continually and controllably passing a polymer film or fiber through a pressurized vessel, while maintaining a desired pressure inside the vessel. In certain embodiments, the devices of the present disclosure include dynamic seals capable of limiting the gas flow from the pressurized vessel to lower pressure environments.
Abstract:
Methods for reducing the density of thermoplastic materials and the articles made therefrom having similar or improved mechanical properties to the solid or noncellular material. Also disclosed are improvements to foaming methods and the cellular structures of the foams made therefrom, and methods for altering the impact strength of solid or noncellular thermoplastic materials and the shaping of the materials into useful articles.
Abstract:
A method for making a shapeable article from poly(lactic acid) includes treating solid poly(lactic acid) that results in the solid poly(lactic acid) having a crystallinity of at least 20% by weight based on the weight of the solid poly(lactic acid) and a gas concentration of 6% to 16% by weight based on the weight of the solid poly(lactic acid); and heating the solid poly(lactic acid) having said minimum crystallinity and gas concentration to produce a cellular poly(lactic acid) article that is shapeable. The shapeable cellular poly(lactic acid) article is advantageous in that the article can be further shaped by heat and/or pressure (or vacuum), such as via thermoforming, into a variety of useful products.