Low density microcellular foams

Patent · Thu Jan 01 00:00:00 EST 1987

OSTI ID:866279

Aubert, James H ^[1]; Clough, Roger L ^[1]; Curro, John G ^[2]; Quintana, Carlos A ^[1]; Russick, Edward M ^[1]; Shaw, Montgomery T ^[3]

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1. Albuquerque, NM
2. Placitas, NM
3. Mansfield Center, CT

Low density, microporous polymer foams are provided by a process which comprises forming a solution of polymer and a suitable solvent followed by rapid cooling of the solution to form a phase-separated system and freeze the phase-separated system. The phase-separated system comprises a polymer phase and a solvent phase, each of which is substantially continuous within the other. The morphology of the polymer phase prior to and subsequent to freezing determine the morphology of the resultant foam. Both isotropic and anisotropic foams can be produced. If isotropic foams are produced, the polymer and solvent are tailored such that the solution spontaneously phase-separates prior to the point at which any component freezes. The morphology of the resultant polymer phase determines the morphology of the resultant foam and the morphology of the polymer phase is retained by cooling the system at a rate sufficient to freeze one or both components of the system before a change in morphology can occur. Anisotropic foams are produced by forming a solution of polymer and solvent that will not phase separate prior to freezing of one or both components of the solution. In such a process, the solvent typically freezes before phase separation occurs. The morphology of the resultant frozen two-phase system determines the morphology of the resultant foam. The process involves subjecting the solution to essentially one-dimensional cooling. Means for subjecting such a solvent to one-dimensional cooling are also provided. Foams having a density of less than 0.1 g/cc and a uniform cell size of less than 10 .mu.m and a volume such that the foams have a length greater than 1 cm are provided.

• Research Organization: AT&T
• DOE Contract Number: AC04-76DP00789
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4673695
• OSTI ID: 866279
• Country of Publication: United States
• Language: English

Related Subjects

density
microcellular
foams
microporous
polymer
provided
process
comprises
forming
solution
suitable
solvent
followed
rapid
cooling
form
phase-separated
freeze
phase
substantially
continuous
morphology
prior
subsequent
freezing
determine
resultant
foam
isotropic
anisotropic
produced
tailored
spontaneously
phase-separates
component
freezes
determines
retained
rate
sufficient
components
change
occur
separate
typically
separation
occurs
frozen
two-phase
involves
subjecting
essentially
one-dimensional
means
cc
uniform
cell
size
10
volume
length
cm
polymer phase
rate sufficient
microcellular foams
solvent phase
rapid cooling
density microcellular
phase separation
comprises forming
polymer foam
suitable solvent
process involves
cell size
microcellular foam
substantially continuous
separation occurs
solvent followed
microporous polymer
cellular foam
phase separate
porous polymer
involves subjecting
/521/210/264/