United States of America As Represented by the Administrator of Nasa

Case Western Reserve University

Elvis Cudjoe

Stuart J Rowan

Baochau N Nguyen

Mary Ann Meador

A dynamic cross-linked polymer nanocomposite adhesive has been developed by the oxidation of a thiol functionalized semi-crystalline and/or amorphous oligomer and thiol functionalized Cellulose Nanocrystals (CNCs) to form a polydisulfide network. The resulting solid material has a melting point transition at ca. 75° C. which corresponds to the melting of the semi-crystalline and/or amorphous phase of the nanocomposite adhesive. At higher temperatures (ca. 150° C.), results in the dynamic behavior of the disulfide bond being induced, where the bonds break and reform. Two levels of adhesion are obtained, in some embodiment by (1) heating the adhesive material to 80° C. (melting the semi-crystalline and/or amorphous phase) resulting in a lower modulus/viscosity of the adhesive, thus allowing better surface wetting on a substrate and (2) heating the adhesive material to 150° C. (inducing dynamic behavior of disulfide bonds), further lowers the modulus/viscosity of the adhesive ensuring a much better surface wetting and stronger adhesive bond. The polymer adhesive has been demonstrated to bind to, relatively high surface energy substrates including metal and hydrophilic glass, and to low surface energy substrates such as hydrophobic glass.

Strong, rebondable, dynamic cross-linked cellulose nanocrystal polymer nanocomposite adhesives

Composite materials including cellulose nanocrystals incorporated into a polymer aerogel scaffold, wherein the cellulose nanocrystals serve as a reinforcement agent to result in the formation of less dense aerogels, improve the tensile mechanical properties of aerogel films, and reduce aerogel shrinkage upon thermal exposure. After gelation, the gel is dried via a suitable method such as supercritical COextraction, freeze drying or other method, to produce the CNC/polymer composite aerogel. Properties of the composite aerogel can be tailored via surface modification of the cellulose nanocrystals as well as through the backbone structure of the polymer.

Growing community of inventors

Cleveland Heights, OH, United States of America

Elvis Cudjoe