Fiber modification via dielectric-barrier discharge theory and practical applications to lignocellulosic fibers

Abstract

Given global emphasis on environmental awareness, the demand for innovative technologies that apply green chemistries to renewable resources for the 21st century will continue to grow [1]. The application of cold plasmas to wood fibers offers means to alter the surface chemistry and physical properties of one of the worlds most abundant renewables. Plasma, the fourth state of matter, can be generated by a variety of methods including high heat conditions, the application of electromagnetic waves at radio and microwave frequencies in a vacuum, or when electrons in an electric current gain energy in amounts sufficient to separate gaseous atoms and molecules causing ionization. The invention of the dielectric-barrier discharge device, which applies an electric current for plasma formation, is attributed toWerner von Siemens, who introduced the concept of dielectric-barrier discharge treatment of air for ozone generation in 1857 [2]. Today, dielectric-barrier discharges continue to be used for ozone generation [3] but have found applications in pollution control [4], silent discharge CO2 lasers and ultraviolet excimer lamps [5], plasma displays [6], and the surface treatment of polymers [7]. The purpose of this review is to provide an overview of current and relevant research into the potential application of dielectric-barrier discharge to the surface modification of lignocellulosic fibers. Impacts of treatment in terms of the surface chemistry, physical strength properties, and water affinity of lignocellulosic fibers are discussed.