Abstract: A blowing agent blend for making thermoplastic polymer foams comprises methyl formate. The blowing agent blend can further comprise at least one co-blowing agent. The co-blowing agent is either a physical co-blowing agent (e.g. an inorganic agent, a hydrocarbon, a halogenated hydrocarbon, a hydrocarbon with polar, functional group(s), water or any combination thereof), or a chemical co-blowing agent, or combinations thereof. The thermoplastic polymer foam can be an alkenyl aromatic polymer foam, e.g. a polystyrene foam. The blowing agent blend can comprise 100 mol % methyl formate, or it can comprise any combination of methyl formate and one or more co-blowing agents. The methyl formate-based blowing agent blends produce stable foams. A process for the preparation of such foams is also provided.

Abstract: A blowing agent blend for making polyolefin foams comprising isopentane and at least one co-blowing agent. The co-blowing agent is either a physical co-blowing agent having a boiling point less than 28° C., or a chemical co-blowing agent, or combinations thereof. The blowing agent blend comprises less than about 99 mol % isopentane.

Abstract: A blowing agent blend for making polyolefin foams comprising isopentane and at least one co-blowing agent The co-blowing agent is either a physical co-blowing agent having a boiling point less than 28° C., or a chemical co-blowing agent, or combinations thereof The blowing agent blend comprises less than about 99 mol % isopentane.

Abstract: The invention disclosed provides integral multilayered polymers with variable interlayer gaps, and processes for their manufacture. The materials thus produced consist of many layers of a polymeric material, which may be a single polymer or a blend of compatible polymers, separated by discontinuous narrow gaps containing air and/or a blowing agent. The layer density can be controlled within a wide range, typically 10 to 2000 layers/mm, while the gap width between the layers can be controlled either to ≦100 nanometers (called nanolayered polymers) or ≧1 micrometer (called microlayered polymers), depending on the process. These layered materials are mechanically strong and have excellent thermal and electrical, and sound insulation properties. Two distinct mechanisms were developed for producing such materials.

Abstract: The invention disclosed provides a method for inducing nucleation in a polymer by subjecting the polymer containing dissolved gas to an external stress generated, for example, by applying hydrostatic or mechanical pressure. The applied stress restricts the bubble growth so that the foamed materials have small cells and high cell density. Such microcellular foams can be produced over a wide low temperature range, i.e. from the temperature at which the polymer is conditioned with the blowing agent up to about the glass transition temperature of the polymer-blowing agent system. Stress induced nucleation can also be conducted at higher temperatures i.e. up to about the Tg of the neat polymer, leading to foams with larger cells. A variety of homogeneous and heterogeneous foams can be produced by this technique.

Abstract: The invention disclosed provides a method for inducing nucleation in a polymer by subjecting the polymer containing dissolved gas to an external stress generated, for example, by applying hydrostatic or mechanical pressure. The applied stress restricts the bubble growth so that the foamed materials have small cells and high cell density. Such microcellular foams can be produced over a wide low temperature range, i.e. from the temperature at which the polymer is conditioned with the blowing agent up to about the glass transition temperature of the polymer-blowing agent system. Stress induced nucleation can also be conducted at higher temperatures i.e. up to about the T.sub.g of the neat polymer, leading to foams with larger cells. A variety of homogeneous and heterogeneous foams can be produced by this technique.

Abstract: The invention disclosed provides a method for producing ultramicrocellular polymer foams at low pressures. A polymer is saturated with a blowing agent at low temperatures and pressures within a short time period, due to retrograde vitrification. The blowing agent may be in the form of a gas or a volatile liquid. Polymer-blowing agent combinations are selected to provide a processing temperature/pressure in the area below the positive slope portion of the retrograde vitrification profile of the glass transition temperature of the polymer versus pressure. The polymer thus saturated has an exceptionally high blowing agent content, and is then foamed to produce materials with small cells and high cell density.