The purpose of this article was to review the biocompatibility, physical, and mechanical properties of the POLYAMIDE denture base materials. An electronic search of scientific papers from 1990-2014 was carried out using PubMed, Scopus and Wiley Inter Science engines using the search terms “nylon denture base” and “POLYAMIDE denture base”. Searching the key words yielded a total of 82 articles. By application of inclusion criteria, the obtained results were further reduced to 24 citations recruited in this review. Several studies have evaluated various properties of POLYAMIDE (nylon) denture base materials. According to the results of the studies, currently, thermo-injectable, high impact, flexible or semi-flexible POLYAMIDE is thought to be an alternative to the conventional acrylic resins due to its esthetic and functional characteristics and physicochemical qualities. It would be justifiable to use this material for denture fabrication in some cases such as severe soft/ hard tissue undercuts, unexplained repeated fracture of denture, in aesthetic-concerned patients, those who have allergy to other denture base materials, and in patients with microstomia. Although POLYAMIDE has some attractive advantages, they require modifications to produce consistently better properties than the current polymethyl methacrylate (PMMA) materials. Moreover, since there is a very limited knowledge about their clinical performance, strict and careful follow-up evaluation of the patients rehabilitated with POLYAMIDE prosthesis is recommended.

Polymer nanocomposites offer a way to bridge the gap between nanomaterials and macroscale materials. Nanocomposites based on MXene (2D transition metal carbide, nitride, or carbonitride) and graphene are a hot topic in the fields of materials and chemistry because of their unique properties. In this research, MXene and graphene oxide were modified by acidified 6-aminocaproic acid and hexamethylene diamine, respectively. The modified MXene and graphene oxide were hybridized through condensation reaction to give MXene-grafted graphene oxide (MXene-g-GO). The resulting MXene-g-GO hybrid filler was further blended with commercial POLYAMIDE 6 (PA6). The effects of MXene, grapheme oxide and MXene-grafted graphene oxide on thermal stability, mechanical properties and electromagnetic interference shielding efficiency of PA6 were investigated through material characterization and relevant tests. The pattern of SEM, XRD and XPS demonstrated that modified MXene (mMXene) was grafted to the surface of modified graphene oxide (mGO) successfully. The results of TGA and mechanical experiments showed that MXene and graphene have a certain synergistic effect on some properties of POLYAMIDE 6 nanocomposites and aggregation between the fillers was alleviated. Besides, PA6 nanocomposites, having improved electromagnetic interference shielding efficiency, can be prepared using hybridized fillers. This study introduced a polymer material that can be used to make the external shell of the communication device, which has a specific reference value to control harming of the electromagnetic waves.

POLYAMIDE-66 (PA66) /CaCO3 micro- and nano-composites were prepared using a polymer solution method at filler loading of 0, 1, 2 and 3 weight percent. Nano-size of CaCO3 was synthesized by micro-emulsion technique. The material was characterized by XRD, SEM, FTIR and UV-VIS techniques. XRD results of composites suggested that CaCO3 particles are found in the amorphous phase of the semi-crystalline thermoplastic and a-crystalline form of thermoplastic is thermodynamically more stable than the g-crystalline forms at room temperature. The uniform dispersion of 1, 2, and 3 wt. % surface modified micro- and nano-CaCO3within PA66 were evidenced from SEM images. FT-IR analysis confirmed the chemical structure of the PA66. Absorption peaks for all required chemical groups were showed in the FTIR spectra: N-H stretch at 3305.52 cm-1, C-H stretch at 2865.02-2936.45 cm-1, Amide-I at 1638.76 cm-1, and Amide-II at 1539.55 cm-1. UV-VIS data showed that the presence of CaCO3 particles in PA66 results in the decrease of energy-band gaps of the composites. In addition, the results showed that incorporation of CaCO3 particles increased the modulus and tensile strength of neat PA66 however decreased its yield and elongation at break.

A series of new POLYAMIDEs containing maleimide pendant group were prepared by low temperature polycondensation of 5- (4- (2, 5-dioxo-2H-pyrrol-1 (5H) -yl) benzamido) isophthaloyl chloride as a new monomer with various aromatic diamines in NMP. Monomer and polymers structures were identified through FT-IR, 1H-NMR and elemental analysis. Obtained polymers were soluble in polar solvents and non soluble in aprotic solvents. The inherent viscosities of the polymers have been determined in NMP and had values from 0.35 to 0.39 dL/g. Thermal stability of polymers was investigated with thermal gravimetry analysis (TGA) and diffraction scanning calorimetry (DSC). Also thermal behavior of monomer was studied with DSC analysis. X-ray diffraction measurement was used to indicate amorphous structure of POLYAMIDE.