Method for clay exfoliation, compositions therefore, and modified rubber containing same

A dry mixing process for providing a butyl rubber composition having low gas permeability comprising:

• a) modifying a clay using at least one organic surfactant having a molecular weight below about 500˜2000 to produce an organically modified clay;
• b) exfoliating the organically-modified clay with a polymeric exfoliant selected from the group consisting of polyisobutylene-based exfoliant and modified butyl rubber by admixing the polymeric exfoliant with the organically modified clay to produce an exfoliated clay;
• and
• c) dry mixing the exfoliated clay with butyl rubber.

A process for providing a butyl rubber composition having low gas permeability comprising:

• a) dissolving a polymeric exfoliant selected from the group consisting of polyisobutylene-based exfoliant and modified butyl rubber in a solvent for the polymeric exfoliant,
• b) swelling clay In a mixture of clay and water;
• c) combining the products of steps a) and b);
• d) drying the product of step c) to obtain an organoclay;
• e) mixing the product of step d) with butyl rubber at about 70° C. to about 175° C.
• wherein the butyl rubber produced by the process has the organo-clay incorporated therein thereby imparting low gas permeability properties to the butyl rubber.

A process for synthesizing a randomly NR2-functionalized poly(isobutylene) by cationic polymerization comprising the steps of:

• a) mixing isobutylene in a solvent system;
• b) cooling the isobutylene/solvent mixture;
• c) adding N,N-dimethylvinylbenzylamine to the mixture an initiator and modifyers;
• d) initiating a polymerization reaction by adding TiCl4;
• e) terminating the polymerization with MeOH;
• and
• f) evaporating any remaining solvents;
• wherein the resulting product of poly(isobutylene-co-N,N-dimethylvinylbenzylamine) is yielded.

A process for producing polyisobutylene amine salt (PIBAS) comprising the steps of:

• a) mixing polyisobutylene succinic anhydride (PIBSA) with a multi-amine compound selected from, for example, 3-(dimethylamino)propylamine, tetraethylene pentamine, 3,3′-diamino-N-methyl dipropylamine, 1-(2-aminoethyl)piperazine, 4-amino-1-benzylpiperidine, dimethylaminovinylbenzylamine, polyethyleneimine, 3-aminopyrrolidine, 3-(dimethylamino)pyrrolidine and N,N′-Bis(3-aminopropyl)ethylene diamine;
• b) heating the mixture to about 150° C.;
• c) maintaining the heated mixture at about 150° C. for about five minutes;
• d) allowing the mixture to cool;
• e) adding HCl and water to the cooled mixture of step d);
• wherein PIBAS Is thereby formed.

A method for exfoliating clay comprising

• a) combining said clay with an organic exfoliant having a molecular weight less than about 700;
• b) combining a polymeric surfactant selected from the group consisting of polyisobutylene-based exfoliant and modified butyl rubber having a molecular weight greater than about 1,000 with an organic solvent;
• c) combining the mixtures of steps a and b and introducing water thereto;
• and
• d) drying the mixture of step c and recovering said exfoliated clay.