This paper investigates the effect of seashell (SS) powders of 75 μm size, reinforced in multi-walled carbon nanotube (MWCNT)-added nylon 66 polymer composite, by studying its mechanical and thermal properties for suitable application in the automotive industry. Seashells were collected from the seashores and the mechanical ball milling method is employed to ground the SSs into powders using a sieve machine, and the desired particulate size of 75 μm is obtained. These particulate SSs are reinforced in the matrix of nylon 66 in different proportions, viz., 3, 6, 9, 12, and 15% by weight along with 1 wt.% of MWCNTs. Twin-screw extruder and injection molding are employed to prepare the testing specimens. Mechanical and thermal tests were carried out as per ASTM standards. From the mechanical and thermal analyses, it is observed that tensile strength and coefficient of linear thermal expansion decrease with an increase in SS content, whereas flexural strength, shore hardness, impact strength, Vicat softening point, and heat deflection temperature rise with higher wt.% of SSs. This is owing to the thermoplastic’s decreased flexibility, which increases its resilience to deflection and load and its high thermal stability. The added MWCNTs improved the bonding strength and mechanical properties due to their higher surface areato- volume ratio.

Compatibility and properties of PP/N66 blends with or without PP-g-MAH as a compatibilizer were investigated by DSC, SEM and universal testing machine. Morphological studies revealed that PP and N66 were incompatible and addition of PP-g-MAH was very effective to enhance the compatibility between PP and N66. The compatibilization effect between N66 and PP-g-MAH was based on the reaction between the amine end group of N66 and anhydride group in PP-g-MAH. The crystallization and melting behavior of PP/N66 blends were investigated and the results of analyses for enthalpy changed were discussed. The Izod impact strength could be improved by optimizing the compatibilizer concentration. Tensile strength, elongation at break, notched Izod impact strength were increased with using compatibilizer, however, both the compatibilized and the noncompatibilizer blends did not show any big difference in the flexural modulus.