Effect of Piperazine Concentration on the Properties of Lower Purity Dimer Acid-Synthesized Polyamide Hot-Melt Adhesive

摘要

Polyamide hot-melt adhesive was synthesized from lower purity, i.e., 75% purity dimer acid, sebacic acid, ethylenediamine and piperazine. The effect of piperazine content on the properties of polyamides, such as thermal properties: heat of fusion (H_f), heat of crystallization (H_c), softening point (T_s) and glass transition temperature (T_g); mechanical properties: tensile strength and hardness; adhesion properties: lap shear strength (LSS) and T-peel strength (IPS); and Theological properties was investigated. Concentration of piperazine was varied from 12.5 to 37.5 molar %. It was found that H_f, H_c, T_s, T_g, tensile strength, hardness, LSS, TPS and viscosity all increased with decrease in molar percentage of piperazine. This is due to increase in crystallinity of the polyamide with decrease in piperazine, giving better packing of molecules in the adhesive, thus giving better properties.