Abstract:
Blocked photographically useful groups decompose thermally via a Lossen rearrangement reaction, including, for example, compounds represented by the following structure: F. In the above structure, the substituents are as defined in the application. Such compounds have good reactivity and can by used to block photographically useful compounds such as developing agents until thermally activated under preselected conditions. Compounds according to the present invention are especially useful in color photothermographic imaging elements.
Abstract:
Blocked photographically useful groups decompose thermally via a Lossen rearrangement reaction, including, for example, compounds represented by the following structure: F. In the above structure, the substituents are as defined in the application. Such compounds have good reactivity and can by used to block photographically useful compounds such as developing agents until thermally activated under preselected conditions. Compounds according to the present invention are especially useful in color photothermographic imaging elements.
Abstract:
A process for making a poly alpha-olefin (PAO) having a relatively high vinylidene content (or combined vinylidene and tri- substituted vinylene content) and a relatively low vinyl and/or di- substituted vinylene content, as well as a relatively low molecular weight. The process includes: contacting a feed containing a C 2 -C 32 alpha-olefin with a catalyst system comprising activator and a bis-cyclopentadienyl metallocene compound, typically a cyclopentadienyl-benzindenyl group 4 transition metal compound.
Abstract:
The invention concerns a radical polymerization method for preparing halogenated polymers, using one or more ethylenically unsaturated monomers whereof at least one is selected among halogenated monomers, molecular iodine and one or more radical generating agents selected among diazo-compounds, peroxides and dialkyldiphenylalkanes. The invention also concerns a method for radical polymerization, starting with halogenated polymers prepared by the above method, of block copolymers whereof at least one block is a halogenated polymer block. The invention further concerns halogenated polymers having a number average molecular weight Mn greater than 1.0.10 and a Mz/Mw ratio less than 1.65. The invention also concerns block copolymers whereof at least one is a halogenated polymer block identical to said halogenated polymers above. Finally, the invention concerns block copolymers comprising at least one halogenated polymer block having a number average molecular weight Mn greater than 1.5.10 and polydispersity index Mw/Mn less than 1.60.
Abstract:
Disclosed herein are methods for producing a polymer. One polymerizes monomers selected from alkene monomers and terminal alkyne monomers, in the presence of a catalyst which is a silylene. The catalyst can be a heterocyclic amido silylene which is at least partially unsaturated within the ring. Also disclosed are polymers produced by the above methods, and improved methods for producing the catalysts.