SYNTHESIS AND PROPERTIES OF CELLULOSE ACETOACETATES

Cellulose acetoacetates with and without other ester groups were prepa red directly from cellulose by reaction with diketene or tert-butyl ac etoacetate (and, where appropriate, a carboxylic anhydride) in N,N-dim ethylacetamide (DMAC)/LiCl or 1-methyl-2-pyrrolidinone (NMP)/LiCl solu tion. This is the only method yet described for the direct synthesis o f these polymers from cellulose and, except for the triester, the only method available for synthesis of cellulose acetoacetates which do no t contain another ester group. The products span the entire degree of substitution (DS) range, are amorphous, and are readily soluble in var ious solvents depending on DS. Cellulose acetoacetates of low DS are s oluble in water. Some of these water-soluble materials can be formulat ed into cross-linkable coatings which have outstanding solvent resista nce. Methods have been developed for the determination of DS by proton NMR spectroscopy. Proton and carbon-13 NMR resonance assignments for cellulose tris(acetoacetate) are also provided.