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%.

Preparation and study on the optical, mechanical, and antibacterial properties of polylactic acid/ZnO/TiO2 shared nanocomposites

2020 ◽  
Vol 36 (3) ◽  
pp. 285-311
Author(s):  
Ali Tajdari ◽  
Amir Babaei ◽  
Alireza Goudarzi ◽  
Razie Partovi
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Antibacterial Activity ◽  
Optical Properties ◽  
Polylactic Acid ◽  
Field Emission ◽  
Antibacterial Properties ◽  
Hydrolytic Degradation ◽  
Scanning Electron

In this research, first, ZnO nanorods were synthesized by hydrothermal method and characterized in terms of morphological and structural properties by means of field emission scanning electron microscopy, Fourier transform infrared, and X-ray diffraction techniques. Subsequently, polylactic acid/ZnO, polylactic acid/TiO2, and polylactic acid/ZnO/TiO2 nanocomposites with different percentages of nanoparticles and two different types of ZnO morphologies were prepared and their microstructural, optical, mechanical, hydrolytic degradation, and antibacterial properties were investigated. Field emission scanning electron microscopy results of polylactic acid/ZnO and polylactic acid/TiO2 samples showed a proper dispersion and nanoparticle distribution for low percentages (up to 5 wt%) and increased aggregation for the higher percentages. Besides, a large increase in the aggregation tendency was observed for combined nanoparticles (polylactic acid/ZnO/TiO2 nanocomposites). Results of the tensile test, the UV–Vis absorption tests, and the hydrolytic degradation tests of the samples showed an enhanced mechanical (approximately 55% increase in the presence of 3–5 wt% of nanoparticles) and light absorption and degradation (approximately 85% increase in the presence of 3–10 wt% of nanoparticles) for the polylactic acid by incorporating nanoparticles. It was also observed that, in addition to the quality of dispersion and distribution of nanoparticles in the polymeric matrix, the type of morphology of nanoparticles can contribute to the improvement of these properties. The cylindrical morphology of ZnO played a greater role on improving the polylactic acid mechanical properties compared to the spherical ZnO morphology (approximately 20%). On the contrary, the increased polylactic acid optical properties and degradation with ZnO spherical morphology were more pronounced (approximately 60%). Interestingly, when both ZnO and TiO2 were added, a synergistic effect in the case of UV-shielding and degradation rate and alternatively, a detrimental effect on the mechanical properties were detected. (The polylactic acid optical properties increased by about 17% and its degradation more than doubled.) Furthermore, the antibacterial activity of polylactic acid was investigated against the two Gram-positive Listeria monocytogenes and Gram-negative bacteria Escherichia coli by incorporating nanoparticles. The results indicated that as the nanoparticle percentage increases, the antibacterial activity steadily increases.

scholarly journals Fabrication and Characterization of Polylactic Acid Electrospun Scaffolds Modified with Multi-Walled Carbon Nanotubes and Hydroxyapatite Nanoparticles

Biomimetics ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 43
Author(s):  
Athanasios Kotrotsos ◽  
Prokopis Yiallouros ◽  
Vassilis Kostopoulos
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Polylactic Acid ◽  
Physical And Mechanical Properties ◽  
Polymeric Materials ◽  
Cost Effective ◽  
Electrospinning Process ◽  
Wide Range ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The solution electrospinning process (SEP) is a cost-effective technique in which a wide range of polymeric materials can be electrospun. Electrospun materials can also be easily modified during the solution preparation process (prior SEP). Based on this, the aim of the current work is the fabrication and nanomodification of scaffolds using SEP, and the investigation of their porosity and physical and mechanical properties. In this study, polylactic acid (PLA) was selected for scaffold fabrication, and further modified with multi-walled carbon nanotubes (MWCNTs) and hydroxyapatite (HAP) nanoparticles. After fabrication, porosity calculation and physical and mechanical characterization for all scaffold types were conducted. More precisely, the morphology of the fibers (in terms of fiber diameter), the surface properties (in terms of contact angle) and the mechanical properties under the tensile mode of the fabricated scaffolds have been investigated and further compared against pristine PLA scaffolds (without nanofillers). Finally, the scaffold with the optimal properties was proposed as the candidate material for potential future cell culturing.

scholarly journals Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Chern Chiet Eng ◽  
Nor Azowa Ibrahim ◽  
Norhazlin Zainuddin ◽  
Hidayah Ariffin ◽  
Wan Md. Zin Wan Yunus ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Polylactic Acid ◽  
Mechanical Analysis ◽  
Basal Spacing ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Thermal Stability Of

The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA)/Polycaprolactone (PCL) blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two Tg of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology.

Preparation and Mechanical Properties of Poly (arylene sulfide sulfone)/Glass Fiber Cloth Composites

2015 ◽  
Vol 815 ◽  
pp. 496-502
Author(s):  
Yu Kong ◽  
Jia Cao Yang ◽  
Xiao Jun Wang ◽  
Gang Zhang ◽  
Sheng Ru Long ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Processing Temperature ◽  
Crosslinking Reaction ◽  
Compression Moulding ◽  
Dynamic Mechanical ◽  
Optimum Processing ◽  
Infrared Spectrometer

Poly (arylene sulfide sulfone)/glass fiber cloth composites (PASS/GFC) were prepared through compression moulding. The optimum processing conditions including temperature, time and pressure were discussed in detail. The cross-linking reaction, mechanical and dynamic mechanical properties were also characterized. The results showed that the optimum processing temperature, pressure and time were 325 °C, 5 MPa and 15 min, respectively. The thioether group (-S-) was oxidized and converted to sulfoxide (-SO-) and sulfone (-SO2-) groups during the crosslinking reaction proved by Fourier transform infrared spectrometer. The mechanical and dynamic mechanical analysis measurements showed that mechanical properties, including tensile, bending, impact and storage modulus increased continuously with an increase of the GFC contents.

The Influence of Alkaline Treatment on Mechanical Properties and Morphology of Rice Husk Fibre Reinforced Polylactic Acid

2014 ◽  
Vol 911 ◽  
pp. 13-17 ◽  
Author(s):  
Abdullah Farah Dina ◽  
Sa’ad Siti Zaleha ◽  
Bonnia Noor Najmi ◽  
Ibrahim Nor Azowa
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Brittle Fracture ◽  
Polylactic Acid ◽  
Rice Husk ◽  
Alkaline Treatment ◽  
Distilled Water ◽  
Internal Mixer ◽  
Fesem Micrographs ◽  
Thermal Stability Of

This study focuses on the influence of surface treatment and fibre sizes on mechanical behavior, physical properties and morphology of rice husk fibre (RHF) reinforced polylactic-acid (PLA). Modified RHF was prepared by using 6w.t.% sodium hydroxide (NaOH) and distilled water. PLA composite reinforced with 25w.t.% volume fractions of modified RHF was mixed using the internal mixer and fabricated by the mini injection moulding. Tensile and flexural strength results showed that the PLA composite with 100, 200 and 500μm particles sizes of water treated fibre are much higher than those of alkaline treated. DSC measurement was performed and indicated that the Tg,Tmand ΔHmof PLA reduced after reinforcement with water treated and alkaline treated fibres. TGA results showed that the treatment reduced the thermal stability of the PLA. FESEM micrographs for flexural fractured surfaces of composites showed micro crack and pores due to brittle fracture of the PLA matrix adjacent to the fibre as a result of the brittle nature of the PLA resin.

scholarly journals Morphology and mechanical properties of polyamide 12 (PA12)/poly(vinylidene fluoride) (PVDF) blends

2009 ◽  
Vol 11 (3) ◽  
pp. 27-34 ◽  
Author(s):  
Aleksandra Ratajska ◽  
Wojciech Kulak ◽  
Artur Poeppel ◽  
Andreas Seyler ◽  
Zbigniew Roslaniec
Keyword(s):  
Mechanical Properties ◽  
Vinylidene Fluoride ◽  
Polymeric Materials ◽  
Scanning Calorimetry ◽  
Crystalline Polymers ◽  
Polyamide 12 ◽  
Poly Vinylidene Fluoride ◽  
Static Tensile ◽  
Internal Mixer ◽  
Morphology And Mechanical Properties

Morphology and mechanical properties of polyamide 12 (PA12)/poly(vinylidene fluoride) (PVDF) blends The morphology, thermal and mechanical properties of polyamide 12 (PA12)/poly(vinylidene fluoride) (PVDF) blends were investigated. These polymers are engineering, semi-crystalline polymers which are reciprocally immiscible. Differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM) were used to characterize the polymeric materials. Mechanical properties were examined by static tensile test. The investigations demonstrate that blends with higher amount of PVDF, with the morphology of two co-continuous semicristalline phases, exhibit better mechanical properties. The blends with small content of PVDF and prepared by extrusion show the morphology of small separated domains of PVDF and full continuous PA phase. The morphology of these blends is different than the blends prepared by internal mixer and have better mechanical properties too. Thus they can be used in particular applications without a compatibilizing agent.

Improving the Mechanical Properties of Ramie-Polylactic Acid Green Composites by Surface Modification using Single Bath Alkaline and Silane Treatment

2021 ◽  
Author(s):  
Swati Sharma ◽  
Abhijit Majumdar ◽  
Bhupendra Singh Butola
Keyword(s):  
Polylactic Acid ◽  
Interfacial Adhesion ◽  
Research Work ◽  
Mechanical Analysis ◽  
Silane Treatment ◽  
Compression Moulding ◽  
Water Contact ◽  
Impact Performance ◽  
Single Bath ◽  
Surface Modified

Abstract This research work emphasises on improving the interfacial adhesion of ramie/ polylactic acid (PLA) composites. For this purpose, ramie fabric was modified using vinyl trimethoxy silane with two different hydrolysing agents, i.e. sodium hydroxide and ammonia. The surface modified ramie fabric was characterised by static water contact angle, elemental dispersive X-ray (EDX) and Fourier transform infrared spectroscopy (FTIR). FTIR and EDX analysis confirmed the presence of silica. The tensile strength of fabric showed a decrease after the silane treatment. The composites were prepared by compression moulding using untreated and treated ramie fabrics with PLA. The treatment improved tensile and impact performance of ramie/PLA composites due to enhanced interfacial adhesion between fibre and matrix. Dynamic mechanical analysis (DMA) results revealed that treated ramie/PLA composites have higher storage modulus and lower tangent delta than untreated composites.

Effect of Fibre Volume Fraction on Mechanical Properties of FRTP Laminates Produced by Film Stacking Method

2015 ◽  
Vol 787 ◽  
pp. 632-636
Author(s):  
R. Parvatham ◽  
K. Chandrasekaran ◽  
S.K. Malhotra
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Mechanical Analysis ◽  
Fibre Volume ◽  
Compression Moulding ◽  
Consumer Durables ◽  
Reinforced Plastics ◽  
Increase With Increase ◽  
End Use

Fiber Reinforced Plastics are now being used in all fields of industry as well as for consumer durables. In the present work, FRP laminates of glass/PP fabricated by film stacking method are studied for various mechanical properties. The glass/PP laminate of required thickness (3-4 mm) is fabricated by stacking a number of FRTP prepregs in the mould and applying heat and pressure in compression moulding press. Dynamic Mechanical Analysis, tensile, flexural and izod impact tests were performed on FRTP laminates. From DMA test, the following viscoelastic properties of GF/PP laminate were observed. (i) The storage modulus increases with increasing fibre volume fraction. (ii) The loss factor decreases with increase in volume fraction. Tensile strength and flexural strength values increase with increase in fibre volume fraction. Impact strength decreases with increase in fibre volume fraction. The results of the present study will be useful in determining the end use applications of FRTP laminates in industry.

scholarly journals The Green Approach to the Synthesis of Bio-Based Thermoplastic Polyurethane Elastomers with Partially Bio-Based Hard Blocks

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2334
Author(s):  
Ewa Głowińska ◽  
Paulina Kasprzyk ◽  
Janusz Datta
Keyword(s):  
Mechanical Properties ◽  
Thermoplastic Polyurethane ◽  
Viscoelastic Behavior ◽  
Polymeric Materials ◽  
Building Blocks ◽  
Chain Extender ◽  
Sustainable Chemistry ◽  
Polyurethane Elastomers ◽  
Thermoplastic Polyurethane Elastomers ◽  
Hard Segments

Bio-based polymeric materials and green routes for their preparation are current issues of many research works. In this work, we used the diisocyanate mixture based on partially bio-based diisocyanate origin and typical petrochemical diisocyanate for the preparation of novel bio-based thermoplastic polyurethane elastomers (bio-TPUs). We studied the influence of the diisocyanate mixture composition on the chemical structure, thermal, thermomechanical, and mechanical properties of obtained bio-TPUs. Diisocyanate mixture and bio-based 1,4-butanediol (as a low molecular chain extender) created bio-based hard blocks (HS). The diisocyanate mixture contained up to 75 wt % of partially bio-based diisocyanate. It is worth mentioning that the structure and amount of HS impact the phase separation, processing, thermal or mechanical properties of polyurethanes. The soft blocks (SS) in the bio-TPU’s materials were built from α,ω-oligo(ethylene-butylene adipate) diol. Hereby, bio-TPUs differed in hard segments content (c.a. 30; 34; 40, and 53%). We found that already increase of bio-based diisocyanate content of the bio-TPU impact the changes in their thermal stability which was measured by TGA. Based on DMTA results we observed changes in the viscoelastic behavior of bio-TPUs. The DSC analysis revealed decreasing in glass transition temperature and melting temperature of hard segments. In general, obtained materials were characterized by good mechanical properties. The results confirmed the validity of undertaken research problem related to obtaining bio-TPUs consist of bio-based hard building blocks. The application of partially bio-based diisocyanate mixtures and bio-based chain extender for bio-TPU synthesis leads to sustainable chemistry. Therefore the total level of “green carbons” increases with the increase of bio-based diisocyanate content in the bio-TPU structure. Obtained results constitute promising data for further works related to the preparation of fully bio-based thermoplastic polyurethane elastomers and development in the field of bio-based polymeric materials.

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