FOOD CONTACT MATERIALS: AN ANALYSIS OF WATER ABSORPTION IN NYLON 12 3D PRINTED PARTS USING SLS AFTER VAPORFUSE SURFACE TREATMENT

Selective laser sintering (SLS) is a typical method of 3D printing in an industrial environment. It is often used to print different materials, such as metals, ceramics, and plastics. Nylon 12 is the most common plastic and material processed by SLS technology. In the present paper, the water absorption and wettability of Nylon 12 in additive manufacturing (AM) products are explored. The research for obtaining inert, non-absorbent and non-corrosive surfaces, and globally more effective materials to reduce the proliferation of microorganisms is becoming a necessity for the development of novel food contact materials. Surface treatments aim at improving the porosity and general roughness of the material and are expected to improve its hydrophobicity. The wetting state between Nylon 12 and water was studied by measuring the contact angles as primary data. The measurement of absorbed water (ASTM 570) is thus used as an indicator of material quality to prevent bacterial growth and degradation of the material mechanical properties. Therefore, water absorption tests were performed with SLS printed plates with and without surface treatment. Plates with surface treatment showed a mass increase of 0.35 +/- 0.04 % while those without surface treatment showed a mass increase of 0.76 +/- 0.08 %. Keywords: Nylon 12; SLS; food contact materials; wetting state; contact angle