Foam of polymers

Abstract

Described herein are foams of polymers and methods of making and using thereof. In certain aspects, the polymer foams include vacuum or gas-filled compartments formed by making a solution of 1 to 20% by weight of a polymer in a solvent; adding particles to the a polymer solution; solidifying the polymer wherein the particles are contained by heating, cooling, aging, or coagulating to obtain a polymer foam or matrix comprising the particles, and obtaining from the polymer matrix the polymer foam containing the compartments; and optionally washing, drying, and/or heating the polymer foam.

1 . A foam comprising a polymer matrix having compartments, which compartments are surrounded by inert or expanded material, or comprising a matrix of a mixture of polymer selected from an aramid and a rigid rod polymer and polymer of the expandable particles, and wherein the compartments are vacuum or filled with a gas. 
     
     
         2 . The foam of  claim 1  wherein the compartments are surrounded by inert material of glass or a ceramic material. 
     
     
         3 . The foam of  claim 1  wherein the polymer is selected from poly(p-phenylene-terephthalamide), poly-4,4′-(3,3′-dihydroxy)-bisphenylene-therephthalamide, poly(p-phenylene-benzobisoxazole), poly(p-phenylene-pyridobisimadazole), and co-poly-(paraphenylene/3,4′-oxydiphenylene terephthalamide. 
     
     
         4 . A foam comprising a polymer matrix having compartments which are vacuum or filled with a gas, wherein the polymer is selected from an aramid and a rigid rod polymer with the proviso that the polymer is not PPTA. 
     
     
         5 . The foam of  claim 4  wherein the polymer is selected from poly-4,4′-(3,3′-dihydroxy)-bisphenylene-therephthalamide, poly(p-phenylene-benzobisoxazole), poly(p-phenylene-pyridobisimadazole), and co-poly-(paraphenylene/3,4′-oxydiphenylene terephthalamide. 
     
     
         6 . The foam of  claim 1  wherein the compartments have an average diameter from 1 to 500 μm. 
     
     
         7 . The foam of  claim 1  having a density from 0.01 to 1 g/cm3. 
     
     
         8 . Shaped article comprising the aramid foam of  claim 1 .