Selective Localization of Multi-walled CNT in Polylactic Acid/Thermoplastic Polyurethane Blends and Its Effect on Mechanical Properties

2018 ◽  
Vol 2 (2) ◽  
pp. 84-89 ◽  
Author(s):  
Yose Fachmi Buys ◽  
Munirah Afiqah Mawardi ◽  
Hazleen Anuar
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Thermoplastic Polyurethane ◽  
Selective Localization

scholarly journals MECHANICAL PROPERTIES, MORPHOLOGY, AND HYDROLYTIC DEGRADATION BEHAVIOR OF POLYLACTIC ACID / THERMOPLASTIC POLYURETHANE BLENDS

2020 ◽  
Vol 21 (1) ◽  
pp. 193-201
Author(s):  
Yose Fachmi Buys ◽  
Mimi Syakina Ahmad ◽  
Hazleen Anuar ◽  
Mudrikah Sofia Mahmud ◽  
Nur Aimi Mohd Nasir
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Thermoplastic Polyurethane ◽  
Hydrolytic Degradation ◽  
Polymeric Materials ◽  
Mechanical Analysis ◽  
Material Degradation ◽  
Compression Moulding ◽  
Degradation Behaviour ◽  
Internal Mixer

Polylactic acid (PLA) has attracted tremendous interest to be utilized as the replacement for petroleum-based polymers as it possesses good biodegradability, can be derived from renewable sources, and shows high mechanical strength. However, its inherent brittleness and low toughness has limited its usage in broader applications. In this work, PLA was melt blended with tough thermoplastic polyurethanes (TPU) in order to produce eco-friendly polymeric materials with balanced mechanical properties. Moreover, the miscibility and the hydrolytic degradation behaviour of PLA/TPU blends were also investigated as it is important to control material degradation behaviour in some applications. Five compositions of specimens, i.e. neat PLA, PLA/TPU 75/25 vol%, PLA/TPU 50/50 vol%, PLA/TPU 25/75 vol%, and neat TPU, were prepared by melt blending PLA with TPU using an internal mixer, followed by compression moulding. Tensile and impact tests were performed to evaluate the mechanical properties. From the tests, it was apparent that the elongation-at-break and impact strength of the blends increased as the TPU content increased. Dynamic Mechanical Analysis (DMA) and Scanning Electron Microscopy (SEM) observation were conducted to evaluate the miscibility of PLA/TPU blends. DMA results of the blends revealed two tangent delta peaks, indicating that the blends were immiscible, and the SEM micrographs supported this trend. Finally, hydrolytic degradation behaviour of PLA, TPU and PLA/TPU blends was investigated by measuring the weight loss after immersion of the specimens in alkaline solution at a predetermined time, i.e. every 24 hours for up to 8 days. It was found that the degradation behaviour is affected by blend composition, where PLA/TPU 50/50 vol% showed the fastest degradation rate. This result might be ascribed to the co-continuous morphology shown in the PLA/TPU blend 50/50 vol%. ABSTRAK: Polilaktik asid (PLA) telah menarik banyak minat untuk digunakan sebagai pengganti polimer berasaskan petroleum, kerana ia mempunyai biodegradabiliti yang baik, boleh diperolehi daripada sumber yang boleh diperbaharui, dan mempunyai kekuatan mekanikal yang tinggi. Walau bagaimanapun, kerapuhan dan keliatannya yang rendah telah menghadkan penggunaannya dalam aplikasi yang lebih luas. Dalam kajian ini, leburan PLA dicampurkan dengan poliuretan thermoplastik (TPU) bagi menghasilkan bahan polimer yang mesra alam beserta dengan sifat-sifat mekanikal yang seimbang. Selain itu, daya kebolehcampuran dan degradasi hidrolitik daripada campuran PLA/ TPU juga telah dikaji kerana bagi sesetengah aplikasi, faktor degradasi adalah sangat penting. Bagi menghasilkan lima komposisi sampel, iaitu PLA tulen, PLA/TPU 75/25 vol%, PLA/TPU 50/50 vol%, PLA/TPU 25/75 vol%, dan TPU tulen, PLA dan TPU telah dicairkan dan diadun menggunakan mesin pencampur internal, diikuti dengan kaedah pengacuan kompresi. Untuk mengkaji sifat-sifat mekanikal, ujian regangan dan impak telah dijalankan. Hasil ujian tersebut menunjukkan peningkatan nilai pemanjangan pada titik putus dan kekuatan impak, seiring dengan peningkatan komposisi TPU. Manakala, penilaian daya kebolehcampuran diantara PLA dan TPU dijalankan menggunakan analisis mekanikal dinamik (DMA) dan mikroskop pengimbas elektron (SEM). Keputusan DMA, hasil daripada campuran tersebut mendedahkan dua puncak tangen delta, menunjukkan bahawa dua campuran tersebut tidak memiliki daya bolehcampur yang baik. Kesimpulan ini disokong pula oleh gambar mikro dari hasil ujian SEM. Akhir sekali, degradasi hidrolitik PLA, TPU dan campuran PLA/TPU dikaji melalui pengukuran berat sampel setelah direndam di dalam larutan alkali pada masa yang ditetapkan, iaitu setiap 24 jam sehingga 8 hari. Hasil daripada ujian tersebut mendapati degradasi hidrolitik dipengaruhi oleh komposisi campuran. Campuran PLA/TPU dengan komposisi 50/50 vol% menunjukkan kadar penurunan berat yang paling cepat. Hasil ujian ini mungkin boleh dikaitkan dengan sifat morfologi co-continuous yang ditunjukkan dalam campuran PLA/TPU 50/50 vol%.

scholarly journals Preparation of Long Sisal Fiber-Reinforced Polylactic Acid Biocomposites with Highly Improved Mechanical Performance

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1124
Author(s):  
Zhifang Liang ◽  
Hongwu Wu ◽  
Ruipu Liu ◽  
Caiquan Wu
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Mechanical Performance ◽  
Tensile Elongation ◽  
Sisal Fiber ◽  
Fiber Reinforced ◽  
Impact Performance ◽  
The Matrix ◽  
Blending Process ◽  
Extension Direction

Green biodegradable plastics have come into focus as an alternative to restricted plastic products. In this paper, continuous long sisal fiber (SF)/polylactic acid (PLA) premixes were prepared by an extrusion-rolling blending process, and then unidirectional continuous long sisal fiber-reinforced PLA composites (LSFCs) were prepared by compression molding to explore the effect of long fiber on the mechanical properties of sisal fiber-reinforced composites. As a comparison, random short sisal fiber-reinforced PLA composites (SSFCs) were prepared by open milling and molding. The experimental results show that continuous long sisal fiber/PLA premixes could be successfully obtained from this pre-blending process. It was found that the presence of long sisal fibers could greatly improve the tensile strength of LSFC material along the fiber extension direction and slightly increase its tensile elongation. Continuous long fibers in LSFCs could greatly participate in supporting the load applied to the composite material. However, when comparing the mechanical properties of the two composite materials, the poor compatibility between the fiber and the matrix made fiber’s reinforcement effect not well reflected in SSFCs. Similarly, the flexural performance and impact performance of LSFCs had been improved considerably versus SSFCs.

Graphene oxide crosslinker for the enhancement of mechanical properties of polylactic acid

2021 ◽  
Author(s):  
Majharul Islam Sujan ◽  
Stephen Don Sarkar ◽  
Chanchal Kumar Roy ◽  
Mohammad Ferdous ◽  
Ankur Goswami ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Polylactic Acid

scholarly journals Evaluation of the influence of design in the mechanical properties of honeycomb cores used in composite panels

2021 ◽  
pp. 146442072098519
Author(s):  
A Miranda ◽  
M Leite ◽  
L Reis ◽  
E Copin ◽  
MF Vaz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Failure Modes ◽  
Industrial Applications ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Distribution Analysis ◽  
Absorbed Energy ◽  
Fused Filament Fabrication ◽  
Subtractive Manufacturing

The aerospace, automotive, and marine industries are heavily reliant on sandwich panels with cellular material cores. Although honeycombs with hexagonal cells are the most commonly used geometries as cores, recently there have been new alternatives in the design of lightweight structures. The present work aims to evaluate the mechanical properties of metallic and polymeric honeycomb structures, with configurations recently proposed and different in-plane orientations, produced by additive and subtractive manufacturing processes. Structures with configurations such as regular hexagonal honeycomb (Hr), lotus (Lt), and hexagonal honeycomb with Plateau borders (Pt), with 0°, 45°, and 90° orientations were analyzed. To evaluate its properties, three-point bending tests were performed, both experimentally and by numerical modeling, by means of the finite element method. Honeycombs of two aluminum alloys and polylactic acid were fabricated. The structures produced in aluminum were obtained either by selective laser melting technology or by machining, while polylactic acid structures were obtained by material extrusion using fused filament fabrication. From the stress distribution analysis and the load–displacement curves, it was possible to evaluate the strength, stiffness, and absorbed energy of the structures. Failure modes were also analyzed for polylactic acid honeycombs. In general, a strong correlation was observed between numerical and experimental results. The results show that the stiffness and absorbed energy increase in the order, Hr, Pt, Lt, and with the orientation through the sequence, 45°, 90°, 0°. Thus, Lt structures with 0° orientation seem to be good alternatives to the traditional honeycombs used in sandwich composite panels for those industrial applications where low weight, high stiffness, and large energy-absorbing capacity are required.

Physical property of 3D-printed sinusoidal pattern using shape memory TPU filament

2020 ◽  
Vol 90 (21-22) ◽  
pp. 2399-2410 ◽  
Author(s):  
Shahbaj Kabir ◽  
Hyelim Kim ◽  
Sunhee Lee
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Shape Memory ◽  
Fused Deposition Modeling ◽  
Loss Modulus ◽  
Thermoplastic Polyurethane ◽  
Heating Process ◽  
Fused Deposition ◽  
3D Printed ◽  
Sinusoidal Pattern

This study has investigated the physical properties of 3D-printable shape memory thermoplastic polyurethane (SMTPU) filament and its 3D-printed sinusoidal pattern obtained by fused deposition modeling (FDM) technology. To investigate 3D filaments, thermoplastic polyurethane (TPU) and SMTPU filament were examined by conducting infrared spectroscopy, x-ray diffraction (XRD), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and a tensile test. Then, to examine the 3D-printed sinusoidal samples, a sinusoidal pattern was developed and 3D-printed. Those samples went through a three-step heating process: (a) untreated state; (b) 5 min heating at 70°C, cooling for 30 min at room temperature; and (c) a repeat of step 2. The results obtained by the three different heating processes of the 3D-printed sinusoidal samples were examined by XRD, DMTA, DSC and the tensile test to obtain the effect of heating or annealing on the structural and mechanical properties. The results show significant changes in structure, crystallinity and thermal and mechanical properties of SMTPU 3D-printed samples due to the heating steps. XRD showed the increase in crystallinity with heating. In DMTA, storage modulus, loss modulus and the tan σ peak position also changed for various heating steps. The DSC result showed that the Tg for different steps of the SMTPU 3D-printed sample remained almost the same at around 51°C. The tensile property of the TPU 3D-printed sinusoidal sample decreased in terms of both load and elongation with increased heating processes, while for the SMTPU 3D-printed sinusoidal sample, the load decreased but elongation increased about 2.5 times.

scholarly journals Additive manufacturing of PLA-based scaffolds intended for bone regeneration and strategies to improve their biological properties

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 571-599
Author(s):  
Ricardo Donate ◽  
Mario Monzón ◽  
María Elena Alemán-Domínguez
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Additive Manufacturing ◽  
Bone Regeneration ◽  
Polylactic Acid ◽  
State Of The Art ◽  
Biological Properties ◽  
Design Stage ◽  
Bone Scaffolds ◽  
Regeneration Of Bone

AbstractPolylactic acid (PLA) is one of the most commonly used materials in the biomedical sector because of its processability, mechanical properties and biocompatibility. Among the different techniques that are feasible to process this biomaterial, additive manufacturing (AM) has gained attention recently, as it provides the possibility of tuning the design of the structures. This flexibility in the design stage allows the customization of the parts in order to optimize their use in the tissue engineering field. In the recent years, the application of PLA for the manufacture of bone scaffolds has been especially relevant, since numerous studies have proven the potential of this biomaterial for bone regeneration. This review contains a description of the specific requirements in the regeneration of bone and how the state of the art have tried to address them with different strategies to develop PLA-based scaffolds by AM techniques and with improved biofunctionality.

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