University of Akron

About: University of Akron is a education organization based out in Akron, Ohio, United States. It is known for research contribution in the topics: Polymer & Polymerization. The organization has 17401 authors who have published 29127 publications receiving 702386 citations. The organization is also known as: The University of Akron.

Flexible Nanofiber-Reinforced Aerogel (Xerogel) Synthesis, Manufacture, and Characterization

Abstract: Silica aerogels are sol-gel-derived materials consisting of interconnected nanoparticle building blocks that form an open and highly porous three-dimensional silica network. Flexible aerogel films could have wide applications in various thermal insulation systems. However, aerogel thin films produced with a pure sol-gel process have inherent disadvantages, such as high fragility and moisture sensitivity, that hinder wider applications of these materials. We have developed synthesis and manufacturing methods to incorporate electrospun polyurethane nanofibers into the cast sol film prior to gelation of the silica-based gel in order to reinforce the structure and overcome disadvantages such as high fragility and poor mechanical strength. In this method, a two-stage sol-gel process was employed: (1) acid-catalyzed tetraethyl orthosilicate hydrolysis and (2) base-catalyzed gelation. By precisely controlling the sol gelation kinetics with the amount of base present in the formulation, nanofibers were electrospun into the sol before the onset of the gelation process and uniformly embedded in the silica network. Nanofiber reinforcement did not alter the thermal conductivity and rendered the final composite film bendable and flexible.

Structures and compositions of copolymers

Abstract: Etude des differentes modelisations utilisees pour les copolymerisations; le modele terminal rend compte de la plupart d'entre elles, mais des modeles plus complexes doivent etre utilises pour rendre compte de l'influence de l'avant dernier motif sur la reactivite du radical et de la reversibilite de la reaction de propagation; presentation des simulations sur ordinateur utilisees pour ces modelisations (Monte Carlo, CSMP, ACSL). Etude de l'effet du solvant sur la copolymerisation de monomeres polaires suggerant l'importance du partage du monomere entre le solvant et le radical polymere