Exploration of Potential Applications of Natural Oils for Green Hot Melt Adhesives: A Comparative Experimental Investigation on Paraffin and Soybean Waxes

摘要

It has been proposed recently to use agricultural products for the development of green hot melt adhesives (HMAs). However, to date ideal green raw materials for the replacement of the petroleum-based ingredients such as paraffin wax in a HMA formulation have never been identified. In this study, to replace the paraffin wax we propose soybean wax as a candidate and further conduct an experimental investigation on its crystalline structure, thermal and mechanical behavior, and crystallization morphology by XRD, DSC, NMR, Texture Analyzer, and PLM, respectively, with an emphasis on the comparison between soybean wax and paraffin wax. It is demonstrated that compared with the paraffin wax, the soybean wax shows a natural difference in molecular and crystalline structures, but it exhibits some similar or even unique characteristics in melt /crystallization temperature, onset time of crystallization, hardness, and microstructures. It is, therefore, suggested that the soybean wax could be a suitable substitute for the paraffin wax, although it is still an open issue whether or not a green HMA containing the soybean wax would show a better practical adhesion performance. Furthermore, it is emphasized that aiming at a specific purpose, such as improvement of green compositions, biodegradability, or low-temperature application, the soybean wax is promising for the formulation of a green HMA with an acceptable functionality.