Material systems and methods of manufacture for auxetic foams

Abstract

A novel material for producing auxetic foams is disclosed. The material comprises a multiphase, multicomponent polymer foam with a filler polymer having a carefully selected glass transition temperature. Novel methods for producing auxetic foams from the material are also disclosed that consistently, reliably and quickly produce auxetic polyurethane foam at about room temperature (25° C.). This technology overcomes challenging issues in the large-scale production of auxetic PU foams, such as unfavorable heat-transmission problem and harmful organic solvents.

1 . (canceled) 
     
     
         2 . The material system of  claim 21 , wherein the filler polymer comprises styrene acrylonitrile copolymer. 
     
     
         3 - 8 . (canceled) 
     
     
         9 . The material system of  claim 29 , wherein the compressed gas is primarily carbon dioxide or nitrogen. 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . The material system of  claim 21 , wherein varying a concentration of the filler polymer in the foam causes variation of mechanical properties of the foam. 
     
     
         13 - 20 . (canceled) 
     
     
         21 . A material system for the production of auxetic foam, comprising: a bulk matrix, comprising:
 a soft domain comprising a polymer chain and having a first glass transition temperature;   a hard domain covalently or non-covalently linked to the polymer chain of the soft domain and having a thermal transition temperature greater than the first glass transition temperature; and   a filler polymer dispersed in the bulk matrix and having a second glass transition temperature greater than the first glass transition temperature and less than the thermal transition temperature.   
     
     
         22 . The material system of  claim 21 , wherein the bulk matrix and filler polymer together comprise a multiphase, multicomponent polymer foam. 
     
     
         23 . The material system of  claim 22 , wherein the polymer foam comprises a polyurethane foam. 
     
     
         24 . The material system of  claim 21 , wherein the polymer chain comprises polymeric polyols. 
     
     
         25 . The material system of  claim 21 , wherein the filler polymer comprises styrene acrylonitrile, polyether sulfone, polysulfone, cyclic olefin copolymers, acrylonitrile-butadiene-styrene, poly(p-phenylene oxide), poly(ether ketone), poly(ether ketone), poly(ether ketone ketone), or combinations thereof. 
     
     
         26 . The material system of  claim 25 , wherein the filler polymer is chosen based on the solubility of carbon dioxide or nitrogen in the filler polymer. 
     
     
         27 . The material system of  claim 21 , wherein the bulk matrix is elastic. 
     
     
         28 . The material system of  claim 21 , wherein the bulk matrix deforms when subjected to a mechanical compressive force. 
     
     
         29 . The material system of  claim 21 , wherein the filler polymer has a shape that changes from generally spherical to generally ellipsoidal when the bulk matrix is subjected to a heating step and/or when the bulk matrix is exposed to a compressed gas.