Abstract: This invention relates to a thermoplastic elastomeric block copolymer and process for the preparation thereof. According to this invention, the block copolymer obtained through block copolymerization process at higher temperature and adding butyllithium in twice during copolymerization are mixed block copolymer of A.sub.1 -B-A.sub.2 /B-A.sub.2 and B-A.sub.2 /B-A.sub.2 (where A represents monovinyl aromatic monomer; B represents conjugated diene monomer) having different blocks, higher elongation and appropriate melt index. The process of this invention is simple and efficient. The thermoplastic elastomeric block copolymer of this invention are particularly useful for various applications of typical styrene butadiene block copolymer, especially plastic modifier.

Abstract: A process for preparing silver-containing catalysts and their carriers for the production of ethylene oxide via ethylene oxidation and also to the applications of said catalysts in producing ethylene oxide.Commercial trihydrated .alpha.-alumina, boehmite, carbonaceous materials, a fluxing agent, fluoride and a binder are mixed with water, kneaded and extruded to form strips which are cut and shaped. The shaped bodies are dried, calcined and converted to a .alpha.-alumina bodies i.e., carriers. This process is characterized by using trihydrated .alpha.-alumina, boehmite alumina and carbonaceous materials which have a good matching of particle sizes and proportions in preparing alumina carriers with the following pore structure:______________________________________ specific surface area 0.2-2 m.sup.2 /g pore volume >0.5 ml/g pore radius >30.mu., 25-10% of total volume <30.mu., 75-90% of total volume.