Particulate materials

Abstract

The present invention provides the use of a particulate polymer material as a support for an active agent, characterised in that said polymer material is a polymer produced by copolymerising an unsaturated heterocyclic monomer and squaric or croconic acid or a derivative thereof.

1 . A method for producing glass particles, said method comprising;
 contacting polymer particles with a glass precursor and heating the particles to generate glass-coated polymer particles, wherein said polymer particles are produced by copolymerising an unsaturated heterocyclic monomer and an acid selected from the group consisting of squaric acid, corconic acid and derivatives thereof.   
     
     
         2 . The method of  claim 1 , further comprising heating said glass-coated polymer particles to a temperature at which the polymer pyrolyzes to generate a hollow glass particle. 
     
     
         3 . The method of  claim 1 , wherein said polymer has the structure 
       
         
           
           
               
               
           
         
         wherein R is selected from the group consisting of the same chemical group and a different chemical group and said same or different chemical group is selected from the group consisting of hydrogen and optionally substituted alkyl; 
         wherein X is selected from the group consisting of a bond and a bridging group; 
         y is selected from the group consisting of zero and a positive integer; and 
         z is a positive integer wherein the value of said z determines the molecular weight of said polymer. 
       
     
     
         4 . A method of making a hollow particulate material comprising;
 pyrolysis of a polymer impregnated with a metal compound causing elimination of said polymer, wherein said polymer is produced by copolymerising of an unsaturated heterocyclic monomer and an acid selected from the group consisting of squaric acid, croconic acid and derivatives thereof.   
     
     
         5 . The method of  claim 4 , wherein said material is selected from the group consisting of hollow titania, hollow silica or hollow iron oxide shells. 
     
     
         6 . The method of  claim 4 , further comprising an active agent. 
     
     
         7 . The method of  claim 4 , wherein said polymer has the structure 
       
         
           
           
               
               
           
         
         wherein R is selected from the group consisting of the same chemical group and a different chemical group and said same or different chemical group is selected from the group consisting of hydrogen and optionally substituted alkyl; 
         wherein X is selected from the group consisting of a bond and a bridging group; 
         y is selected from the group consisting of zero and a positive integer; and 
         z is a positive integer wherein the value of said z determines the molecular weight of said polymer. 
       
     
     
         8 . A method comprising;
 use of a hollow particulate glass as a support for an active agent, wherein said hollow particulate glass is produced by pyrolysis of a glass-coated polymer, said polymer being produced by copolymerising an unsaturated heterocyclic monomer and an acid selected from the group consisting of squaric acid, croconic acid and derivatives thereof.   
     
     
         9 . The method of  claim 8 , wherein the active agent or a precursor thereto is loaded after pyrolysis of the glass-coated polymer. 
     
     
         10 . The method of  claim 8 , wherein said polymer has the structure 
       
         
           
           
               
               
           
         
         wherein R is selected from the group consisting of the same chemical group and a different chemical group and said same or different chemical group is selected from the group consisting of hydrogen and optionally substituted alkyl; 
         wherein X is selected from the group consisting of a bond and a bridging group; 
         y is selected from the group consisting of zero and a positive integer; and 
         z is a positive integer wherein the value of said z determines the molecular weight of said polymer. 
       
     
     
         11 . A particulate composition comprising;
 substrate particles containing an active agent, said substrate particles being particles of a polymer produced by copolymerising an unsaturated heterocyclic monomer and an acid selected from the group consisting of squaric acid, croconic acid and derivatives thereof, coated with a glass-forming coating and pyrolyzed.   
     
     
         12 . The particulate composition of  claim 11 , wherein said polymer has the structure 
       
         
           
           
               
               
           
         
         wherein R is selected from the group consisting of the same chemical group and a different chemical group and said same or different chemical group is selected from the group consisting of hydrogen and optionally substituted alkyl; 
         wherein X is selected from the group consisting of a bond and a bridging group; 
         y is selected from the group consisting of zero and a positive integer; and 
         z is a positive integer wherein the value of said z determines the molecular weight of said polymer. 
       
     
     
         13 . A method comprising;
 use of a particulate polymer material as a support for an active agent, wherein said particulate polymer is produced by copolymerising an unsaturated heterocyclic monomer and an acid selected from the group consisting of squaric acid, croconic acid and derivatives thereof.   
     
     
         14 . The method of  claim 13 , wherein said copolymerization is carried out in a solvent in which said polymer becomes insoluble as it grows. 
     
     
         15 . The method of  claim 13 , wherein said heterocyclic monomer is selected from the group consisting of 2,5-unsubstituted pyrrole and 5,5′-unsubstituted-2,2′-bis-pyrrole. 
     
     
         16 . The method of  claim 13 , wherein said polymer has the structure 
       
         
           
           
               
               
           
         
         wherein R is selected from the group consisting of the same chemical group and a different chemical group and said same or different chemical group is selected from the group consisting of hydrogen and optionally substituted alkyl; 
         wherein X is selected from the group consisting of a bond and a bridging group; 
         y is selected from the group consisting of zero and a positive integer; and 
         z is a positive integer wherein the value of said z determines the molecular weight of said polymer. 
       
     
     
         17 . The method of  claim 13 , wherein said particulate polymer material is loaded with a compound selected from the group consisting of a metal compound in dissolved form and an organometallic compound. 
     
     
         18 . A hollow particulate material comprising;
 a pyrolyzed polymer impregnated with a metal compound causing elimination of said polymer, wherein said polymer is produced by copolymerising of an unsaturated heterocyclic monomer and an acid selected from the group consisting of squaric acid, croconic acid and derivatives thereof.   
     
     
         19 . The particular material of  claim 18 , wherein said polymer has the structure 
       
         
           
           
               
               
           
         
         wherein R is selected from the group consisting of the same chemical group and a different chemical group and said same or different chemical group is selected from the group consisting of hydrogen and optionally substituted alkyl; 
         wherein X is selected from the group consisting of a bond and a bridging group; 
         y is selected from the group consisting of zero and a positive integer; and 
         z is a positive integer wherein the value of said z determines the molecular weight of said polymer.