Claims
        
                - 1. A polycyclic-polysiloxane A-B-A block copolymer comprising a polycyclic A block made up of repeating units derived from one or more norbornene-type monomers and a polysiloxane B block.
 
                - 2. The A-B-A block copolymer of claim 1 wherein said polycyclic A block repeating units are represented by the formula: wherein a represents the number of repeating units, n is 0 to 4, R1 to R4 independently represent hydrogen, linear and branched (C1-C20)alkyl, linear and branched (C2-C20)alkenyl, (C3-C20)alkynyl, hydrocarbyl substituted and unsubstituted (C5-C12)cycloalkyl, hydrocarbyl substituted and unsubstituted (C5-C12)cycloalkenyl, (C6-C24)aryl, (C7-C15)aralkyl, R1 and R2 can be taken together to represent (C1-C10)alkylidenyl, R3 and R4 can be taken together to represent (C1-C10)alkylidenyl, R1 and R4 taken together with the two ring carbon atoms to which they are attached represent saturated and unsaturated cyclic groups of 4-12 carbon atoms and aromatic rings of 6 to 17 carbon atoms.
 
                - 3. The A-B-A block copolymer of claim 1 wherein said polysiloxane B block is represented by the formula: wherein a represents the number of repeating units, RIO independently represents (C1-C15)alkyl and (C6-C24)aralkyl.
 
                - 4. A polycyclic-polysiloxane A-B-A block copolymer represented by the formula: wherein PNB represents a polycyclic A block comprising repeating units represented by the structure: wherein n is 0 to 4, R1 to R4 independently represent hydrogen, linear and branched (C1-C20)alkyl, linear and branched (C2-C20)alkenyl, (C3-C20)alkynyl, hydrocarbyl substituted and unsubstituted (C5-C12)cycloalkyl, hydrocarbyl substituted and unsubstituted (C5-C10)cycloalkenyl, (C6-C24)aryl, (C7-C15)aralkyl, R1 and R2 can be taken together to represent (C1-C10)alkylidenyl, R3 and R4 can be taken together to represent (C1-C10)alkylidenyl, R1 and R4 taken together with the two ring carbon atoms to which they are attached represent saturated and unsaturated cyclic groups of 4-12 carbon atoms and aromatic rings of 6 to 17 carbon atoms; and wherein R10 independently represents (C1-C15)alkyl and (C6-C24)aralkyl; and a in the above formulae represents the number of repeating units.
 
        
                
                        Parent Case Info
        This is a division of patent application Ser. No. 08/450,648 filed on May 25, 1995 now U.S. Pat. No. 6,294,616.
                
                
                
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4381396                             | 
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                            A | 
                        
                        
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4826916                             | 
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                            A | 
                        
                
            
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                        | Number | 
                        
                        Date | 
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                            | 2143246 | 
                            
                            Feb 1985 | 
                            GB |