Properties Of Polyamide Composites Research Articles

Graphene/polyamide-6 microsphere composites with high electrical and mechanical performance

The development of innovative methods to prepare graphene-based polymer composites with remarkable properties has become a priority due to the many practical applications of these microstructures. Herein, a new technology was used to fabricate composites by combining graphene materials and polymer microspheres. Polyamide 6 (PA6) microspheres were synthesised by reaction-induced phase separation method, and they were wrapped with few-layer graphene (FLG) or graphene oxide (GO) by exfoliated adsorption method, which allows FLG and GO sheets to form a three-dimensional network structure in the PA6 matrix. Electrical and mechanical characterisation led to a distinct improvement in the properties of PA6 composites, which were superior to traditional graphene/polymer composites. Moreover, the process proposed in this work proved to be an effective method to prepare graphene/polymer composites, suitable for industrial production, and can be extended to other kinds of composites with nanofillers.

Effects of anhydrites before and after modification as well as their contents on the thermal and mechanical properties of polyamide 6/anhydrite composites

The anhydrite (AII) is treated with different methods: calcination (c-AII) and surface modification (c-AIIg, AIIg) by γ-glycidoxy-propyltrimethoxysilane (GPS), and the polyamide 6 (PA6)/anhydrite composites are prepared by a twin-screw extruder. The effects of different anhydrites as well as their contents on the thermal and mechanical properties of PA6 composites are studied in the present work. Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy demonstrate that the active GPS chains are chemically tethered onto the surface of the anhydrite. The differential scanning calorimetry measurements indicate that different anhydrites act as a heterogeneous nucleation agent in PA6 matrix and lead to the appearance of new γ-PA6 crystalline form. Thermogravimetric analysis suggests that the addition of anhydrite after calcination or surface modification has little effect on the thermal stability of the composites. Moreover, it is found that the impact strength of the composites is decreased with the increasing content of different anhydrites, while the tensile strength is increased with the increase of c-AIIg and AIIg content and the most significant improvement of the tensile strength of PA6/c-AIIg and PA6/AIIg composites is obtained when the content of c-AIIg and AIIg is 15 wt%, respectively. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

Properties of Polyamide-6 Composites Reinforced with Hydroxyapatite Nanospheres

Hydroxyapatite nanospheres (nHA) were first synthesized from (NH4)2HPO4 and CaCl2 precursors in the presence of poly(vinyl alcohol) templates. The structure and morphology of as-synthesized products were examined by materials characterization techniques. X-ray diffraction patterns and Fourier transform infrared spectra showed that the nHA (50–70 nm) exhibit the crystalline structure and vibration bands of HA. The Ca/P molar ratio of nHA approached the stoichiometric value of 1.67. The nHA were then melt blended with polyamide-6 (PA6), followed by injection molding. Tensile and flexural measurements showed that the tensile and bending strengths of injection molded PA6–10 wt% nHA composite were close to those of human cortical bone. A simulated body fluid immersion test revealed that apatite crystals can be readily deposited on the PA6–10 wt% nHA composite surface after immersion for 30 days.

Investigation on the Polyamide 6/SEBS-g-MA/Organoclay Nanocomposites with Glycidyl Methacrylate as a Compatibilizer

Polyamide 6 (PA6)/maleated styrene-ethylene/butadiene-styrene copolymers (SEBS-g-MA)/organoclay (DK5) composites with glycidyl methacrylate (GMA) as a compatibilizer were prepared by melt compounding. The influences of maleating, DK5 and GMA on interfacial adhesion and mechanical properties of PA6 composites were investigated in terms of SEM observations, mechanical testing, Molau tests, IR analyses, and rheological behavior. Satisfactorily balanced mechanical properties of the composite could be achieved in the presence of GMA. Both DK5 and GMA retarded the crystallization of PA6. The storage modulus, loss modulus, and complex viscosity of the composites were obviously affected by the addition of DK5 and GMA.

Effect of Commercial & Nano-Ca3(PO4)2 on Mechanical and Thermal Properties of Polyamide Composites

Polyamide/Ca3(PO4)2 nanocomposites were prepared via melt intercalation on twin-screw extruder. Different particle sizes (21, 17, 11 nm) of Ca3(PO4)2 were synthesized by in situ deposition technique and its sizes were confirmed on X-ray difractometer. Amount of loading of nano-Ca3(PO4)2 in the polyamide was ranges in the 1 to 4-wt%. Properties such as tensile strength, elongation at break, hardness, and flame retardency were studied. These results were then compared with commercial Ca3(PO4)2 filled polyamide composites. Improvement in properties was due to uniform dispersion of nano-Ca3(PO4)2 and commercial Ca3(PO4)2. Moreover, thermal property like degradation, weight loss was studied on TGA. Extent of dispersion of nano-Ca3(PO4)2 was studied along with cracks generated during tensile testing using scanning electron microscope (SEM). Nano-Ca3(PO4)2 was found to be thermally more stable compared to that of commercial Ca3(PO4)2. Besides that, the shape and sizes of nano-Ca3(PO4)2 was confirmed on transmission electron microscope (TEM).

Influence of heat treatment regimes on the structure and mechanical properties of polyamide composites

We analyze changes in the structural characteristics and mechanical properties of composite materials with a polyamide matrix depending on the type of heat treatment. It is shown that thermocyclic treatment with a decrease of temperature to cryogenic temperatures leads to partial cold recrystallization in nanofilled materials and to an increase in the adhesive strength of glass-filled specimens.