In-situ addition of carboxylated cellulose nanocrystals in seeded semi-batch emulsion polymerization

Nanocellulosic materials can be used as green materials for property modification in latex polymers. In particular, cellulose nanocrystals (CNCs) can be incorporated in latexes in-situ-a preferable method to ex-situ addition because it ensures latex homogeneity and better performance enhancements. DextraCel is a commercial CNC with carboxylate surface groups, henceforth referred to as cCNC. The interactions between cCNCs and other standard latex components are studied, and experiments reveal that cCNCs can be sensitive to the ionic strength of the aqueous phase of the latex. A reproducible method to incorporate cCNCs in-situ in a seeded semi-batch emulsion polymerization is developed for the production of latexes for adhesive applications by varying the surfactant-initiator systems in the seed stage and the feed stage. Sodium dodecyl sulphate (SDS) and potassium persulphate (KPS), negatively charged surfactant and initiator, respectively, are used for the seeding reaction, and Triton X-405 and 2,2 '-azobisisobutyronitrile (AIBN) (uncharged surfactant and initiator) are used in the feed to preserve low ionic strength of the latex, thereby producing stable latexes.

Automated summary

Nanocellulosic materials can be used as green materials for property modification in latex polymers, especially cellulose nanocrystals. It was found that the nanocrystals are sensitive to the ionic strength of the aqueous phase in latexes. By adjusting the surfactant-initiator systems, it is possible to successfully incorporate nanocrystals in-situ in emulsion polymerization for stable latex production.