An organically modified montmorillonite/nylon‐12 composite powder for selective laser sintering

The purpose of this paper is to reinforce the selective laser sintering (SLS) parts of nylon‐12 using organically modified montmorillonite (OMMT).

A dissolution‐precipitation process is developed to prepare an OMMT/nylon‐12 composite powder (3 wt% OMMT). X‐ray diffraction (XRD) was used to characterize nanostructure features. The dispersion of OMMT in the nylon‐12 matrix was observed by scanning electron microscope (SEM). The effect of OMMT on the thermal properties of nylon‐12 was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The mechanical properties of the SLS parts made from the composite powder and neat nylon‐12 powder were measured and compared.

The X‐ray diffraction and SEM results indicate that the OMMT is intercalated by nylon‐12 molecular chains and uniformly dispersed in the nylon‐12 matrix during the dissolution‐precipitation process, and thus the OMMT/nylon‐12 intercalated nanocomposites are formed. The DSC and TGA results show that the OMMT can increase the melting enthalpy, relative crystalline content, crystallization temperature and thermal stability of nylon‐12. The tensile strength, tensile modulus, flexural strength, flexural modulus and impact strength of the SLS specimens made from the composite powder are 23.2, 31.7, 18.7, 32.4 and 8.4 percent higher than those of neat nylon‐12 SLS specimens, respectively, while the elongation at break decreases by 17.5 percent.

The conclusion of forming intercalated nanocomposites was drawn from the XRD results in the present work. Further work should be done to observe the nanostructures of the materials by transmission electron microscope.

A dissolution‐precipitation process was used to prepare OMMT/nylon‐12 composite powders for SLS process. During the preparation process the OMMT could be intercalated by nylon‐12 molecular chains and uniformly dispersed in the nylon‐12 matrix, thus forming the OMMT/nylon‐12 intercalated nanocomposites. Therefore, the mechanical and thermal properties of nylon‐12 SLS parts were enhanced.