Effect of Nylon-6 Concentration on the Properties of Hot Melt Adhesive Synthesized using Dimer Acid and Ethylenediamine
Hot melt adhesive synthesized using polymerized fatty acid (PFA) (composition: ~1% trilinoleic acid, ~97% dilinoleic acid and ~2% linoleic acid) and ethylenediamine was blended with nylon-6, in-situ during the synthesis process to improve its performance properties. Nylon-6 was added in concentrations as 5, 10, 15 and 20 phr in the hot melt adhesive. The prepared blends were characterized for thermal (melting temperature, crystallization temperature, enthalpy of melting and enthalpy of crystallization), mechanical (tensile strength, tensile modulus, stiffness, percentage elongation at break and hardness), adhesion (lap shear strength and T-peel strength) and rheological properties. It was found that the viscosity, tensile strength, tensile modulus, stiffness, hardness, melting temperature, enthalpy of melting, crystallization temperature and enthalpy of crystallization increased with increase in concentration of nylon-6 in the hot melt adhesive. But lap shear strength and T-peel strength increased up to 10 phr concentration of nylon-6 above which both started decreasing. Percentage elongation at break decreased with increase in concentration of nylon-6 in the hot melt adhesive. Hot melt adhesive molecules must have oriented themselves about nylon-6, increasing its crystallinity, and thus the strength of the adhesive.