|M.Sc Student||Belous Ayelet|
|Subject||Development and Characterization of Plasticized Polyamides|
by Fluid and Solid Plasticizers
|Department||Department of Chemical Engineering||Supervisor||Professor Emeritus Moshe Narkis|
|Full Thesis text|
Polyamide is a semicrystalline polymer useful in a wide range of applications in the plastics industry. Some applications require higher flexibility and workability of polyamides, thus a plasticization approach which could ease compounding and processing procedures and produce better desired product properties. Frequently used plasticizers are high-boiling liquid esters, but recently solid plasticizers also have been considered as adequate. The plasticizer may reduce the polymer glass transition temperature (Tg), along with modifying its other properties. The present research has focused on plasticization of Nylon 66/6 (80/20) using selected low molecular weight organic materials. Plasticization of polyamide was studied with Glycerin Mono Stearate (GMS), Benzene Sulfonamide (BSA), and Methyl 4-hydroxybenzoate (M4HB) as the solid plasticizers and Diethylhexyl Phthalate (DOP) as the liquid plasticizer. The materials were characterized for thermal, mechanical, dynamic, rheological and morphological properties. Best plasticization results were achieved with the M4HB additive. The decrease in Tg was the most significant as well as the reduction of the Young's modulus, melt viscosity, and increase of elongation to break.
Microscopy observations revealed phase separation at 20%wt which implied that solubility saturation of this plasticizer within the polyamide has occurred below 20%.
BSA also decreased the Tg but the reduction in the melt viscosity was smaller and the tensile elongation at break at high concentrations did not increase. An antiplasticization phenomenon was observed for DOP at low loadings as the Young's modulus increased and the elongation at break decreased. The plasticization threshold was reached at 10% wt DOP. GMS showed only a slight effect of plasticization of the polyamide. Its function resembles a processing-aid, as it significantly decreased the melt viscosity but caused small variation of Nylon's mechanical and thermal properties.