scholarly journals Using Carbon-fibre Reinforcement with a 5-axis Material Extrusion System

2019 ◽  
Vol 299 ◽  
pp. 06002
Author(s):  
Nathaniel Kaill ◽  
Patrick Pradel ◽  
Guy Bingham ◽  
R Ian Campbell
Keyword(s):  
Compressive Strength ◽  
Lactic Acid ◽  
Marked Improvement ◽  
Mechanical Performance ◽  
Failure Mechanisms ◽  
Poly Lactic Acid ◽  
Fibre Reinforcement ◽  
Material Extrusion ◽  
The Poor ◽  
Pure Poly

One of the main limitations of material extrusion (ME) components is their anisotropic mechanical behaviour, mainly due to the poor bonding between layers. 5-axis ME has the capability to orientate theprint layers in line with loading conditions, in order to limit the effect of poor inter-laminar bonding. Previous work has demonstrated how aligning deposited material in the same direction as the dominant stresses can improve a part’s mechanical performance. When fibre-reinforcement is added to theseoriented layers, the stiffness and strength of parts should increase further. This paper presents a comparison between 5-axis parts that were printed in pure poly-lactic acid (PLA) and in carbon-fibrereinforced (CFR) PLA. Sets of dome-shaped components were built using several different build strategies and tested for compressive stiffness and strength. The results were rather mixed but did show a marked improvement in compressive strength under certain conditions. Further work is required to understand one of the failure mechanisms that was seen and to overcome some of the limitations of the 5-axis machine currently being used. The work was undertaken to support the Directional Composites through Innovative Manufacturing (DiCoMI) project, funded by the European Commission.

Effect of Polyethylene Glycol in Nanocellulose/PLA Composites

2019 ◽  
Vol 821 ◽  
pp. 89-95
Author(s):  
Wanasorn Somphol ◽  
Thipjak Na Lampang ◽  
Paweena Prapainainar ◽  
Pongdhorn Sae-Oui ◽  
Surapich Loykulnant ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Polyethylene Glycol ◽  
Aspect Ratio ◽  
Mechanical Performance ◽  
Tensile Modulus ◽  
Poly Lactic Acid ◽  
Solvent Casting ◽  
Casting Method ◽  
Mediated Oxidation

Poly (lactic acid) or PLA was reinforced by nanocellulose and polyethylene glycol (PEG), which were introduced into PLA matrix from 0 to 3 wt.% to enhance compatibility and strength of the PLA. The nanocellulose was prepared by TEMPO-mediated oxidation from microcrystalline cellulose (MCC) powder and characterized by TEM, AFM, and XRD to reveal rod-like shaped nanocellulose with nanosized dimensions, high aspect ratio and high crystallinity. Films of nanocellulose/PEG/PLA nanocomposites were prepared by solvent casting method to evaluate the mechanical performance. It was found that the addition of PEG in nanocellulose-containing PLA films resulted in an increase in tensile modulus with only 1 wt% of PEG, where higher PEG concentrations negatively impacted the tensile strength. Furthermore, the tensile strength and modulus of nanocellulose/PEG/PLA nanocomposites were higher than the PLA/PEG composites due to the existence of nanocellulose chains. Visual traces of crazing were detailed to describe the deformation mechanism.

scholarly journals Mechanical Properties and Bioactivity of Poly(Lactic Acid) Composites Containing Poly(Glycolic Acid) Fiber and Hydroxyapatite Particles

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 249
Author(s):  
Han-Seung Ko ◽  
Sangwoon Lee ◽  
Doyoung Lee ◽  
Jae Young Jho
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Flexural Strength ◽  
Interfacial Adhesion ◽  
Glycolic Acid ◽  
Compact Bone ◽  
Poly Lactic Acid ◽  
Coupling Reactions ◽  
The Poor ◽  
Human Compact Bone

To enhance the mechanical strength and bioactivity of poly(lactic acid) (PLA) to the level that can be used as a material for spinal implants, poly(glycolic acid) (PGA) fibers and hydroxyapatite (HA) were introduced as fillers to PLA composites. To improve the poor interface between HA and PLA, HA was grafted by PLA to form HA-g-PLA through coupling reactions, and mixed with PLA. The size of the HA particles in the PLA matrix was observed to be reduced from several micrometers to sub-micrometer by grafting PLA onto HA. The tensile and flexural strength of PLA/HA-g-PLA composites were increased compared with those of PLA/HA, apparently due to the better dispersion of HA and stronger interfacial adhesion between the HA and PLA matrix. We also examined the effects of the length and frequency of grafted PLA chains on the tensile strength of the composites. By the addition of unidirectionally aligned PGA fibers, the flexural strength of the composites was greatly improved to a level comparable with human compact bone. In the bioactivity tests, the growth of apatite on the surface was fastest and most uniform in the PLA/PGA fiber/HA-g-PLA composite.

scholarly journals Hybrid Biocomposites Based on Poly(Lactic Acid) and Silica Aerogel for Food Packaging Applications

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4910 ◽  
Author(s):  
Alejandro Aragón-Gutierrez ◽  
Marina P. Arrieta ◽  
Mar López-González ◽  
Marta Fernández-García ◽  
Daniel López
Keyword(s):  
Thermal Stability ◽  
Lactic Acid ◽  
Silica Aerogel ◽  
Food Packaging ◽  
Mechanical Performance ◽  
Composite Films ◽  
Barrier Properties ◽  
Extrusion Process ◽  
Poly Lactic Acid ◽  
Barrier Performance

Bionanocomposites based on poly (lactic acid) (PLA) and silica aerogel (SiA) were developed by means of melt extrusion process. PLA-SiA composite films were plasticized with 15 wt.% of acetyl (tributyl citrate) (ATBC) to facilitate the PLA processability as well as to attain flexible polymeric formulations for films for food packaging purposes. Meanwhile, SiA was added in four different proportions (0.5, 1, 3 and 5 wt.%) to evaluate the ability of SiA to improve the thermal, mechanical, and barrier performance of the bionanocomposites. The mechanical performance, thermal stability as well as the barrier properties against different gases (carbon dioxide, nitrogen, and oxygen) of the bionanocomposites were evaluated. It was observed that the addition of 3 wt.% of SiA to the plasticized PLA-ATBC matrix showed simultaneously an improvement on the thermal stability as well as the mechanical and barrier performance of films. Finally, PLA-SiA film formulations were disintegrated in compost at the lab-scale level. The combination of ATBC and SiA sped up the disintegration of PLA matrix. Thus, the bionanocomposites produced here show great potential as sustainable polymeric formulations with interest in the food packaging sector.

Rice Bran/Poly(lactic acid) Composites in Packaging Product

2014 ◽  
Vol 931-932 ◽  
pp. 57-62
Author(s):  
Rapeephun Dangtungee ◽  
Rapeeporn Srisuk ◽  
Suchart Siengchin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Lactic Acid ◽  
Rice Bran ◽  
Food Packaging ◽  
Pressure Range ◽  
Research Work ◽  
Magnesium Stearate ◽  
Poly Lactic Acid ◽  
Molding Process

This research work was carried out on the production of rice bran/poly (lactic acid) (PLA) composites. The composition during the batch molding process included rice bran, PLA, glycerol, and magnesium stearate (mold released agent). Afterwards, the composition was molded by bio-compression at temperature of 170°C for 5 min, and a pressure range of 50-100 kg/cm3. The result showed that the composition of rice bran, PLA, and glycerol could be used in the formation of food packaging. Also the mechanical properties, such as compressive strength and hardness, were investigated. It could be concluded that the most appropriate formulation of rice bran packaging was 5 phr PLA and 3 phr glycerol and 2 phr magnesium stearate. Moreover, FTIR results indicated the non-toxic nature of this method of food packaging.

Biodegradable Mg Strengthened Poly-Lactic Acid Composite through Interfacial Properties

2017 ◽  
Vol 900 ◽  
pp. 7-11
Author(s):  
Muhammad Shoaib Butt ◽  
Jing Bai ◽  
Feng Xue
Keyword(s):  
Lactic Acid ◽  
Body Fluid ◽  
Biomedical Applications ◽  
Mechanical Performance ◽  
High Strength ◽  
Poly Lactic Acid ◽  
Magnesium Alloy Az31 ◽  
Injection Process ◽  
Good Potential ◽  
Plastic Injection

High-strength magnesium alloy (AZ31) reinforced poly-lactic acid (PLA) composite rods for potential application of bone fracture fixation prepared by plastic injection process on Mg rod.Thecomposities possess improved the interfacial bonding between poly-lactic acid and Mg rod due to the micro-anchoring which lead to better mechanical performance in Simulated body fluid solution.The present results indicated that this new PLA-clad Mg composite rods show good potential for biomedical applications.

Effect of various enzymatic treatments on the mechanical properties of coir fiber/poly(lactic acid) biocomposites

2019 ◽  
pp. 089270571986461
Author(s):  
Kubra Coskun ◽  
Aysenur Mutlu ◽  
Mehmet Dogan ◽  
Ebru Bozacı
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Coir Fiber ◽  
Test Results ◽  
Fiber Reinforced ◽  
Remarkable Effect ◽  
The Impact

The effects of enzymatic treatments on the properties of coir fiber-reinforced poly(lactic acid) (PLA) were not found in the literature. Accordingly, the effects of various enzymatic treatments on the mechanical performance of the coir fiber-reinforced PLA composites were investigated in the current study. Four different enzymes, namely lipase, lactase, pectinase, and cellulase, were used. The mechanical properties of the composites were determined by the tensile, flexural, impact tests, and dynamic mechanical analysis. According to the test results, the use of enzyme treated coir fibers affected the mechanical properties except for the flexural properties with different extents depending upon their type. The tensile strength increased with the treatments of lipase and lactase, while the treatments with pectinase and cellulase had no remarkable effect. The impact strength was improved with enzymatic treatments except for pectinase. All enzymatic treatments improved the elastic modulus below the glass transition temperature. In brief, enzymatic treatments improved the interfacial adhesion between coir fiber and PLA via the waxes and fatty acids removal and/or the increment in surface roughness.

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