The Journal of Adhesion Science and Technology (JAST) has focused on the basic aspects, theories, and mechanisms of adhesion and deals with applications of adhesion principles in all areas of technology. Dr. Mittal, who is the Editor-in-Chief of JAST, invited me to organize and compile a Special Issue, ‘Adhesion Aspects in the Building Industry’, spotlighting indoor air-quality science relating with adhesion. A number of researchers in the field of indoor air quality researching building materials and adhesives have contributed by studying and writing articles on a variety of topics ranging from principal theories to application technologies.
Among all pollutants, building materials play a major role in determining the indoor air quality owing to their larger surface area and permanent exposure to indoor air. Building materials can release a wide range of pollutants, particularly volatile organic compounds (VOCs), which can degrade the indoor air quality making it worse than that of outdoor air. Recent studies of VOC emissions in newly built and unoccupied test houses showed that the building materials are the main source of indoor air pollution. Polymeric materials are used widely in buildings for the construction, decoration, and furnishing of homes, offices, schools, as well as other nonindustrial work places. Many of these materials are high VOC emitters, such as solvent-borne paints and adhesives. Some constitute large surface areas within buildings such as coatings and coverings on walls, ceilings, and floors. Wood-based panels such as particleboard, medium density fiberboard, and veneer are used widely in the manufacture of furniture, flooring, housing, and other industrial products. These consumer products contain formaldehyde-based resins on account of the latter’s superb bonding properties and low cost. However, wood-based panels bonded with urea-formaldehyde resin emit formaldehyde, which is toxic and is associated with possible health hazards, such as irritation of the eyes and the upper respiratory tract.
This Special Issue introduces 19 papers ranging from advanced adhesion theories to practical experiments with building materials with adhesives. Kang, D.H. et al. evaluate VOC emission and sorption behaviors in building materials with low-VOC adhesives. Small-chamber emission and sorption experiments were designed parallel to field measurements to examine the on-site VOC emission and sorption rates of adhesive-bonded building materials. Sung, M., Lee, S., and Min, Y. present the results of measuring indoor formaldehyde concentrations in newly built apartment buildings at the preoccupancy stage for more than three years. Formaldehyde emissions from engineered wood materials used in floorings and furniture were measured using the small chamber method. These measurements verified that improving the engineered wood materials used in the apartment buildings had an effect on formaldehyde concentrations. Choi, D.H. et al. discuss the effect of the bonding installation of wood flooring under cold weather conditions on indoor air quality and analyze an on-site strategy that can ensure the adhesion strength of the wood flooring and improve indoor air quality. To examine the temperature effects of adhesive bonding on VOC emissions from wood flooring, the emission rates of flooring composites were compared with those from adhesive and plywood flooring as individual materials under temperature variations in a small-scale chamber. Kim, S. and Cho, B. investigate the influence of tile adhesive emissions on their indoor air quality. The VOC and formaldehyde emission rates from two different types of tile adhesives – a conventional adhesive and a low-VOC emission adhesive – were measured using small chambers. Navarrete, P. et al. focused on spray-dried glyoxalated lignin used in tannin/lignin adhesives for exterior and interior-grade wood particleboard and other type of panels that has been shown to be capable of maintaining its reactivity after spray drying with no decrease of performance of the adhesive. Segovia, C., Zhou, X., and Pizzi, A. studied holding wood pieces together by rotationally welded dowels inserted in the side of the wood substrate slats, which can be used to make blockboard panels. Belleville, B. et al. define optimal wood-dowel welding parameters for two North American hardwood species frequently used for indoor appearance products: sugar maple and yellow birch. Park, J.Y. et al. examined effects of laminate type on the emission of VOCs from particleboard and MDF panels using a 20 L small chamber method. Lee, Y. and Kim, H.J. investigate the effect on the curing behavior, activation energy of the curing reaction, crystalline structure, cross-linking, and free formaldehyde content of the addition of the following scavengers in urea-formaldehyde resins: medium density fiber board flour, rice husk flour, silica powder, and tannin powder. Seo, J., Lee, S., Kim, S., and Nam, Y. discuss air exchange rate of the chamber, the loading factor of materials, and mass transfer coefficient which are very important factors in the measurement of chemical compounds because they have a decisive effect on emission rates of chemical compounds emitted from materials.
Lastly, I hope all the studies in the Special Issue will be valuable references for future work. I would like to express my appreciation to authors who contributed to this finished work and their passion toward academic improvement in this field. Moreover, I thank Dr. Mittal for giving me a chance to make a commitment to complete this Special Issue as Guest Editor. I believe that JAST will obviously be in-charge of the most important scientific and technological contribution in adhesion work.