Patricia H. Winfield

The use of flame ionisation technology to improve the wettability and adhesion properties of wood

Flame ionisation technology has been used in an attempt to enhance the performance of exterior surface coatings with timber through an improvement in the wettability of the wood. Preliminary surface energy data indicate that total surface energy values can indeed be improved by an increase in the polar component of the energy. Flame treatment is not affected by surface preparation prior to treatment, although the response of the surface may be influenced by the amount of polar extractives in the timber.

Disbonding Technology for Adhesive Reversible Assembly in the Automotive Industry

Development of the automotive industry is currently driven by three fundamental considerations, i.e. environment, safety and cost, within a strong legislative framework. The reduction of material waste, production stages and weight have become key factors within this scope in the design of vehicles. Therefore, it is important to make greater use of non-conventional materials to take advantage of their recyclability, light weight and mechanical properties, for example new alloys and reinforced polymeric matrix composites (PMC). The dissimilar nature of the materials makes adhesive bonding the principal assembly technique for structural and semi-structural applications. Despite the enhanced performance and durability provided by the use of adhesives compared to that of more conventional joining technologies, bonded materials are very difficult to separate for recycling or reusing components at end of life. Currently, disassembly of adhesive bonded structures is conducted ineffectively by mechanical force, heat, and solvent or acid immersion. Previous research, to overcome these limitations has been mostly for applications other than automotive. Normally, reversible adhesive bonding is obtained through the development of engineered thermoplastic and/or thermosetting resins or incorporation of functional additives into commercial formulations. These technologies generally result in adhesive bonded joints with limited reliability, decreased adhesion strength and reduced resistance to higher temperature. Therefore, no effective disbonding technology has been developed for structural and semi-structural applications for the automotive industry. A comprehensive review will be presented on the adhesive disbonding technology which is currently or intended to be used by industry. This will highlight the advantages and limitations of the various techniques in order to develop an effective disbonding method for the next generation of vehicles at the end of life cycle (ELC).

Self-hot-melt joining of polymers to lacquered metal surfaces

Abstract Metal cans represent the dominant form of packaging in the food and beverage markets. Organic coatings i.e., lacquers, are applied to the inside of the cans to prevent undesirable interactions. The most common lacquer is based upon epoxy–phenolic materials. Advances in packaging technology have directed a requirement for the non-adhesive attachment of thermoplastic compounds, lids and fixtures such as gas capsules “Widgets” to the coatings of metal cans. This represents a new challenge and requires adaptation of the joining techniques currently available. This paper examines the joining of thermoplastic materials to epoxy–phenolic-lacquer-coated tin-free steel. A range of thermoplastics was characterised by their mechanical, thermal and surface energetic properties. A particular joining technique was then developed involving the simultaneous heating and pressing of the coated metal against the thermoplastic component. The process parameters of temperature, pressure and time were evaluated in terms of the properties of the bond. The mechanical behaviour of different types of peel joint was investigated, together with the influence of the moisture content of the thermoplastics.

Continuously Reinforced Metal Matrix Composites

Continuous fiber reinforced metal matrix composites (MMCs) presents the architecture or arrangement of fiber in matrix materials that offer realization of the highest possible mechanical and thermal management properties from the combination. The highest forms of specific stiffness, strength, fatigue and creep resistance are realized in this form of composite compared to particulate and short fiber reinforced MMCs. This chapter presents the types of matrix and fiber materials that are commonly used for the fabrication of long fiber reinforced MMCS. It presents the factors that influence the choice of fiber and matrix for the fabrication and the type of reaction problems that can occur during the high temperature processing that is often required. The types of fabrication methods such as liquid, physical and chemical vapor deposition methods, matrix coated fiber, foil–fiber–foil, and more recently ultrasonic processes are highlighted. The initiatives that have been taken to mitigate deleterious interfacial reaction are discussed. The effects of fiber volume fraction and mismatch of the fiber and the matrix properties on residual stress generated during fabrication and its consequent effects on fatigue and creep are underscored. The potentials of the composite have not been fully realized due to high processing cost. This has reflected in the unstable interests and involvement of manufacturing companies in its production over the years. The chapter lists outstanding suppliers of fibers and long fiber MMCs. Demonstrator components mainly for aerospace and electric power distribution industries are highlighted. Electric power distribution Al/Alumina fiber MMC cables that has become a commercial success case in diverse parts of the world is also presented.

Automotive Structures: Design for Disassembly and the Role of Adhesive Bonding

A controllable adhesive disbonding mechanism can be achieved by activating functional additives located within the matrix of an adhesively bonded joint. This action facilitates the disassembly and material recovery from structurally bonded assemblies. The engineering capabilities of bonded joints containing a range of physical foaming agents were investigated. The effect of the physical foaming agents on joint disassembly was mostly attributable to the volumetric expansion efficiency of the additive whilst constrained within an adhesive matrix.