Effect of water conditioning on the fracture behavior of PA12 composites processed by selective laser sintering

Seltzer, R.; Escalera, Federico Martín de la; Segurado, J.

doi:10.1016/j.msea.2011.05.045

Cited by 38 publications

(28 citation statements)

References 17 publications

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“…The Young's modulus of the composite (2.74 GPa) was enhanced by 130% compared to that of neat PA12 (1.18 GPa), which indicated an improved mechanical stability in the PA12/GBs composite. The Young's modulus values of the MJF-printed components are in agreement with those reported in the literature for both the neat PA12 (Caulfield, McHugh, and Lohfeld 2007;Yuan et al 2016;Cano, Salazar, and Rodríguez 2018) and PA12/GBs composites (Seltzer, de la Escalera, and Segurado 2011;Cano, Salazar, and Rodríguez 2018).…”

Section: Mechanical Propertiessupporting

confidence: 90%

A detailed evaluation of surface, thermal, and flammable properties of polyamide 12/glass beads composites fabricated by multi jet fusion

Guo

Luo

et al. 2021

Virtual and Physical Prototyping

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Multi jet fusion (MJF) is an emerging powder three-dimensional (3D) printing technology with an ultrafast printing speed, in which polyamide 12 (PA12) is the main material currently utilised. Although structurally sophisticated 3D components have been printed by MJF, there are limitations due to the high cost of printing materials and inferior performance of the printed parts. Here, PA12/glass beads (PA12/GBs) composites with improved performance were manufactured via the MJF technique. Incorporating GBs effectively regulated the dimensional accuracy. Furthermore, the composite possessed lower surface roughness and higher surface hardness than neat PA12. Thermal analysis showed that the composite exhibited an enhanced decomposition temperature (390°C) and char yield (38.4 wt.%) compared to neat PA12. Remarkably, the incorporation of GBs did not improve the flame retardance of neat PA12. We identified the improved functionalities of PA12/GBs composites in terms of dimensional accuracy, surface, and thermal properties and analysed possible mechanisms for the observed increased flammability.

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Section: Mechanical Propertiessupporting

confidence: 90%

A detailed evaluation of surface, thermal, and flammable properties of polyamide 12/glass beads composites fabricated by multi jet fusion

Guo

Luo

et al. 2021

Virtual and Physical Prototyping

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“…It clearly shows that the mechanical properties strongly depend on the moisture absorption time with a relatively rapid drop over the first »200 min followed by a much slower rate of decrease. The decrease is ascribed to the plasticisation effect of water, [9,12,42] as it increases polymer flexibility or mobility. The absorption of water results in a decrease of the T g of the polymer, [9] with a »50 C reduction in glass transition temperature when saturating dry nylon 6 in water.…”

Section: 3mentioning

confidence: 99%

Investigation of the nanomechanical properties of nylon 6 and nylon 6/clay nanocomposites at sub-ambient temperatures

Chen

Beake

Bell

et al. 2016

Journal of Experimental Nanoscience

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The nanomechanical properties of nylon 6, nylon 6/exfoliated clay and nylon 6/non-exfoliated clay nanocomposites have been investigated from room temperature to ¡10 C in a controlled environment with humidity less than 1% RH. The hardness, elastic modulus and creep resistance of nylon 6 were improved in the nanocomposites across the temperature range. However, the effective reinforcement of the clay depended on the temperature due to the change between the glassy and transition states in the nylon. The exfoliated clay nanocomposite showed the greater improvements than in the non-exfoliated clay nanocomposite at all testing temperatures due to the improved constraint of the polymer chains by the clay platelets in the exfoliated structure. The surface mechanical properties of nylon 6 and the nanocomposites were also found to be highly sensitive to the moisture level during the tests; increasing the humidity in the room temperature tests resulted in a dramatic decrease in hardness and stiffness due to plasticisation by water molecules. The kinetics of the re-humidification process on nylon 6 were studied by monitoring the change in nanoindentation response. Analysis of the indentation creep revealed a significant change in the strain rate sensitivity when the humidity of the near-surface region probed by nanoindentation was in the vicinity of the glass transition.

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“…In their spherical form, they are reported to allow for high packing fractions, enhanced flow characteristics, increased part isotropy and less warpage -therefore making them a common choice for reinforcement [24,25]. In terms of mechanical performance, thermoplastic filled glass bead parts have been well characterised for SLS [24,[26][27][28]. Cano et al [27] studied the influences of temperature and print orientation on the mechanical properties of PA12 and PA12 reinforced with glass beads, printed via SLS.…”

Section: Introductionmentioning

confidence: 99%

“…They found the fracture behaviour of the PA12 composite was unaffected by the temperature or print orientation and that the fracture resistance of the composite was extremely poor in comparison to the PA12 polymer parts. Seltzer et al [26] evaluated the effect of water on PA12 and PA12 reinforced with glass beads, fabricated using SLS and demonstrated that it caused a deterioration in mechanical performance. Chung et al [17] investigated SLS printed Nylon 11, reinforced with glass beads and observed that the tensile and compressive modulus increases, while the strain at break and yield decreases as a function of glass bead volume.…”

Section: Introductionmentioning

confidence: 99%

Comparison between the properties of polyamide 12 and glass bead filled polyamide 12 using the multi jet fusion printing process

Connor

Dowling

2020

Additive Manufacturing

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This study investigates the material and mechanical properties of both polyamide 12 (PA12) and reinforced glass bead PA12 composites, fabricated using a production scale additive manufacturing (AM) process. The printing studies were carried out using the production scale, Multi Jet Fusion powder bed fusion process. The study demonstrated that the chemical functionality and the thermal properties of the printed PA 12 parts and the glass bead composite, were similar. Almost identical infrared spectra were obtained demonstrating the same chemical functionality. Based on DSC measurements, the melting temperature was 184°C and 186°C and the associated cooling cycle temperature was 150°C and 146°C for the composite and the PA12 respectively. The percentage crystallinity of the glass bead composite was 24 %, compared with the 31% obtained for the PA12 only parts. Based on mechanical tests, the addition of glass beads increased the tensile and flexural modulus by 85% and 36% and lowered the tensile and flexural strength by 39% and 15% respectively. The effect of print orientation during the MJF process was evaluated based on porosity and mechanical performance. Using X-ray micro computed tomography, it was demonstrated that the porosity of the PA12 and composite parts were less than 1%. Polymer and composite parts printed in the ZYX orientation were found to exhibit both the lowest porosity and highest mechanical strengths.

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Effect of water conditioning on the fracture behavior of PA12 composites processed by selective laser sintering

Cited by 38 publications

References 17 publications

A detailed evaluation of surface, thermal, and flammable properties of polyamide 12/glass beads composites fabricated by multi jet fusion

A detailed evaluation of surface, thermal, and flammable properties of polyamide 12/glass beads composites fabricated by multi jet fusion

Investigation of the nanomechanical properties of nylon 6 and nylon 6/clay nanocomposites at sub-ambient temperatures

Comparison between the properties of polyamide 12 and glass bead filled polyamide 12 using the multi jet fusion printing process

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