High-Performance Adhesive Joint Made from Densified Wood.

The strength of an adhesive joint plays a major role in the implementation of engineering wood products; therefore, joint performance receives intense scrutiny. This study investigated a wooden adhesive joint, made from densified wood, the performance of which was dramatically enhanced. The wood sample was developed by performing mechanical compression and polymer impregnation on rubberwood.

Development of Structural Insulated Panels Made from Wood-Composite Boards and Natural Rubber Foam.

An experimental study was carried out to develop and examine the properties of a new type of structural insulated panel (SIP). SIP prototypes conducted from this research consisted of insulated foam manufactured from natural rubber filled with wood particles as the core layer and three kinds of commercial wood-composite boards (plywood, cement particleboard, and fiber-cement board) as the surface layers. Polyurethane was used as an adhesive bond between the surface and the core layer.

Temperature-actuated changes in wettability at elastomer/water interfaces.

Surface modification of 1,4-polybutadiene and cis-1,4-polyisoprene to introduce polar functional groups provided surfaces that reconstructed reversibly against water as a function of temperature. These surfaces became hydrophobic in contact with hot water, but their original hydrophilicity returned upon equilibration against cold water. Repeated cycling between hot and cold water, however, led to a damping of this reversibility.

A smart adhesive joint: entropic control of adhesion at a polymer/metal interface.

The study of adhesion has a long and rich history, with theory, experiments, and applications bridging numerous disciplines, including physics, chemistry, engineering, and medicine. This diverse interest has led to the development of a large number of methods for both enhancing and inhibiting adhesion at specific interfaces of interest. We report herein "smart" adhesion at a polymer/metal (oxide) interface that responds reversibly to changes in temperature by increasing or decreasing in magnitude.

Integration of bulk and interfacial properties in a polymeric system: rubber elasticity at a polybutadiene/water interface.

Oxidation of the surface of cross-linked 1,4-polybutadiene provided a hydrophilic substrate that reconstructed against hot water to become more hydrophobic. Subsequent equilibration against water at room temperature returned its original hydrophilicity. These temperature-dependent changes in the relative concentrations of hydrophobic and hydrophilic moieties at the polymer/water interface are interpreted as arising from the entropic influence of chain extension, associated with rubber elasticity.