EFFECT OF ELECTROMAGNETIC-SENSITIVE PARTICLES ADDITION ON REVERSIBILITY PERFORMANCES OF HOT-MELT ADHESIVES

In this research, the effect of electromagnetic-sensitive additives on the reversibility performance of Hot-Melt Adhesives (HMA), is studied. Test Single Lap Joints (SLJ) were made of Acrylonitrile Butadiene Styrene (ABS) adherends that were bonded using the modified thermoplastic HMA. The heat produced by the interactions of a high-frequency electromagnetic field with the particles is used to bond the test joints. Particles of 2 sizes were added to the adhesive in 6 increasing weight percentages, up to 70 %. Variables such as process time, adhesive thickness and surface preparation were kept constant for all the specimens. Tensile-shear tests at 2 different temperatures, before and after environmental exposure, and debonding tests were performed. A Dynamic Mechanical Analyzer (DMA) was used to characterize the adhesive with different levels of enrichment. SLJ strength was found to be lower for moderate levels of adhesive enrichment, while it raised for higher weight percentages. Larger particle size and environmental cycling reduced considerably the static performances of the joints. Tests performed at 70 °C revealed a dramatic drop in Load Transfer Capacity (LTC), for both pristine and enriched adhesives. Debonding tests showed that the time required for the joints disassembling shortens increasing the level of particles enrichment and particulate size, in accordance with what observed during the manufacturing process. DMA results revealed that the particles enrichment does not modify the effect of temperature on the viscoelastic properties of the adhesive.