Polyesteramide hot melt adhesive (HMA) was synthesized using low purity dimer acid (composition: 3% linoleic acid, 75% dimer acid, and 22% trimer acid), ethanolamine, and ethylenediamine. Ethanolamine was added as a partial replacement (10, 20, and 30%) of ethylenediamine. Prepared HMAs were characterized for acid value, amine value, hydroxyl value, Fourier transform infrared spectroscopy, mechanical (tensile strength, percentage strain at brea, and shore D hardness), thermal (glass transition temperature, melting temperature, enthalpy of melting, crystallization temperature, and enthalpy of crystallization), rheological (viscosity versus shear rate and viscosity versus time), and adhesion properties (T-peel strength and lap shear strength). Replacement of ethylenediamine by ethanolamine replaced certain amide linkages by ester linkages, decreasing the intermolecular hydrogen bonding, leading to decrease in the crystallinity of the material, and thus the mechanical, thermal, adhesion, and rheological properties. However, HMAs prepared using ethanolamine will have better low temperature flexibility due to low glass transition temperature and better adhesion process due to the lower viscosity. 1. Introduction Hot melt adhesives (HMAs) are solid adhesives which when heated are converted to a molten liquid state for application to substrates whereas on cooling quickly, they set up the bond [1]. The substrates must be joined immediately on application of the HMA [2]. When hardened, HMA can have various degrees of tackiness depending on the formulation. Conventional HMAs cool to harden and do not chemically cross-link. Such systems have an open time from few seconds to few minutes [1]. Materials that are primarily used as HMAs include ethylene and vinyl acetate copolymers (EVA), polyvinyl acetates (PVAc), polyethylene (PE), amorphous polypropylene (PP), block copolymers (styrene butadiene rubber, SBR), polyamides (PA), and polyester (PEster). HMAs are solid at temperatures below 80°C. Typical application temperatures are 150–200°C [2]. The most important advantage of HMA is the ability of being able to preapply, for example, as powder or adhesive spheres, in melt liquid form, as dispersion or as an adhesive foil. The joining procedure does not have to take place directly after applying the adhesive to the substrate; this can happen at any time later on [3]. The market for HMA is mainly in the manufacture of durable goods. Examples are shoe assembly, kitchen and bathroom cabinets, telecommunication cable repair sleeves, and window assembly [4]. First PEA based
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