scholarly journals Effect of layered silicate reinforcement on the structure and mechanical properties of spent polyamide-12 nanocomposites

2012 ◽  
Vol 43 (3) ◽  
pp. 1363-1367 ◽  
Author(s):  
B. Aldousiri ◽  
H.N. Dhakal ◽  
S. Onuh ◽  
Z.Y. Zhang ◽  
N. Bennett ◽  
...  
2015 ◽  
Vol 37 (11) ◽  
pp. 3167-3174 ◽  
Author(s):  
S. Sánchez-Valdes ◽  
E. Ramírez-Vargas ◽  
L.F. Ramos de Valle ◽  
J.G. Martinez-Colunga ◽  
J. Romero-Garcia ◽  
...  

2016 ◽  
Author(s):  
Roberto A. Nascimento ◽  
Adriana M. Catelli de Souza

2013 ◽  
Vol 844 ◽  
pp. 53-56
Author(s):  
Saravalee Saengthaveep ◽  
Sadhan C. Jana ◽  
Rathanawan Magaraphan

To produce a tough material for application demanding high impact resistance and low moisture absorption, melt blending of Nylon12 (Polyamide 12, PA12) and natural rubber (NR) was carried out in a brabender plasticorder at 210 °C with rotor speed of 70 rpm in the presence of polystyrene/maleated natural rubber (PS/MNR) blend as a compatibilizer. The effect of compatibilizer content (1, 3, 5, 7 and 10 phr) on phase morphology, thermal, and mechanical properties of [Nylon12/NR]/[PS/MNR] blends was investigated by using SEM, DSC, and Izod impact tester, respectively. The result revealed that PS/MNR blend improved the compatibility of Nylon12/NR blends efficiently due to the presence of amide linkage at the interfaces from the reaction between the reactive groups of MNR and the NH2 end groups of Nylon12 during mixing. A fine phase morphology (good dispersion and small dispersed phase size of NR domains in Nylon12 matrix) of [Nylon12/NR]/[PS/MNR] blends was observed at the optimum compatibilizer content of 7 phr, relating to the improvement of mechanical property. The impact energy of [Nylon12/NR]/[PS/MNR] blends was 503 J/m higher than that of neat Nylon12 (115 J/m) and Nylon12/NR binary blend (241 J/m) due to the toughening effect of rubber and proper morphology. The melting temperature of all blends did not change obviously from thermal analysis. However, the presence of rubber particle obstructed the crystallization of Nylon12 phase, leading to the decreasing of %crystallinity from 93% to around 70%.


2021 ◽  
Vol 7 (2) ◽  
pp. 38
Author(s):  
Nectarios Vidakis ◽  
Markos Petousis ◽  
Lazaros Tzounis ◽  
Emmanuel Velidakis ◽  
Nikolaos Mountakis ◽  
...  

In this study, nanocomposites with polyamide 12 (PA12) as the polymer matrix and multiwalled carbon nanotubes (MWCNTs) and carbon black (CB) at different loadings (2.5, 5.0, and 10.0 wt.%) as fillers, were produced in 3D printing filament form by melt mixing extrusion process. The filament was then used to build specimens with the fused filament fabrication (FFF) three-dimensional (3D) printing process. The aim was to produce by FFF 3D printing, electrically conductive and thermoelectric functional specimens with enhanced mechanical properties. All nanocomposites’ samples were electrically conductive at filler loadings above the electrical percolation threshold. The highest thermoelectric performance was obtained for the PA12/CNT nanocomposite at 10.0 wt.%. The static tensile and flexural mechanical properties, as well as the Charpy’s impact and Vickers microhardness, were determined. The highest improvement in mechanical properties was observed for the PA12/CNT nanocomposites at 5.0 wt.% filler loading. The fracture mechanisms were identified by fractographic analyses of scanning electron microscopy (SEM) images acquired from fractured surfaces of tensile tested specimens. The nanocomposites produced could find a variety of applications such as; 3D-printed organic thermoelectric materials for plausible large-scale thermal energy harvesting applications, resistors for flexible circuitry, and piezoresistive sensors for strain sensing.


2002 ◽  
Vol 740 ◽  
Author(s):  
Pralay Maiti ◽  
Carl A. Batt ◽  
Emmanuel P. Giannelis

ABSTRACTNanocomposites of α-hydroxy polyester, polylactide (PLA) and β-hydroxy polyester, polyhydroxybutyrate (PHB) with layered silicates have been successfully prepared by melt extrusion of PLA and PHB with organically modified montmorillonite (MMT) and fluoromica. The mechanical properties of the nanocomposites are improved compared to the neat polymers. Storage modulus increase up to 40% compared with the pure polymers by adding only 2–3 wt% nanoclay. Biodegradation can be controlled by the choice of the nanoclay used.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tiago Czelusniak ◽  
Fred Lacerda Amorim

Purpose This paper aims to provide a detailed study on influence of the laser energy density on mechanical, surface and dimensional properties of polyamide 12 (PA12) parts produced by selective laser sintering (SLS), providing the microstructural and crystallization evolution of the samples produced at different energy densities. Design/methodology/approach Making use of a space filling design of experiments, a wide range of laser sintering parameters is covered. Surface morphology is assessed by means of profile measurements and scanning electron microscopy (SEM) images. Mechanical testing, SEM, X-ray diffraction (XRD), differential scanning calorimeter (DSC) and infrared spectroscopy (FTIR) were used to assess the influence of energy density on structural and mechanical properties. Findings Results show a high dependency of the properties on the laser energy density and also a compromise existing between laser exposure parameters and desired properties of laser sintered parts. Surface roughness could be associated to overlap degree when using higher scan line spacing values and lower laser speeds improved surface roughness when high scan line spacing is used. Higher mechanical properties were found at higher energy density levels, but excessively high energy density decreased mechanical properties. A transition from brittle to ductile fracture with increasing energy density could be clearly observed by mechanical analysis and SEM. XRD and DSC measurements show a decrease on the crystal fraction with increasing energy densities, which corroborated the plastic behavior observed, and FTIR measurements revealed polymer degradation through chain scission might occur at too high energy densities. Originality/value Valuable guidelines are given regarding energy density optimization for SLS of PA12 considering not only quality criteria but also microstructure characteristics. Surface properties are studied based on the concept of degree of overlap between laser scanning lines. For the first time, crystallization behavior of SLS PA12 parts produced at different energy levels was studied by means of XRD measurements. Polymer degradation of SLS PA12 parts was evaluated with FTIR, which is a non-destructive and easy test to be conducted.


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