scholarly journals Optimisation on Thermoforming of Biodegradable Poly (Lactic Acid) (PLA) by Numerical Modelling

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 654
Author(s):  
Huidong Wei

Poly (lactic acid) (PLA) has a broad perspective for manufacturing green thermoplastic products by thermoforming for its biodegradable properties. The mechanical behaviour of PLA has been demonstrated by its strong dependence on temperature and strain rate at biaxial deformation. A nonlinear viscoelastic model by the previous study was employed in a thermoforming process used for food packaging. An optimisation approach was developed by achieving the optimal temperature profile of specimens by defining multiple heating zones based on numerical modelling with finite element analysis (FEA). The forming process of a PLA product was illustrated by modelling results on shape evolution and biaxial strain history. The optimal temperature profile was suggested in scalloped zones to achieve more even thickness distribution. The sensitivity of the optimal results was addressed by checking the robustness under perturbation.

2019 ◽  
Vol 11 (34) ◽  
pp. 31317-31327 ◽  
Author(s):  
Evie L. Papadopoulou ◽  
Uttam C. Paul ◽  
Thi Nga Tran ◽  
Giulia Suarato ◽  
Luca Ceseracciu ◽  
...  

2019 ◽  
pp. 089270571986827 ◽  
Author(s):  
Mehrnoush Monshizadeh ◽  
Sajad Seifi ◽  
Iman Hejazi ◽  
Javad Seyfi ◽  
Hossein Ali Khonakdar

Synergistic effects of organo-modified Mg-Al layered double hydroxide (LDH) and triethyl citrate (TEC) on the properties of poly(lactic acid) (PLA) were demonstrated. PLA/LDH nanocomposites in the absence and presence of TEC were fabricated via solution casting technique. Morphological analysis revealed that as the LDH concentration increases, the number of aggregations is also increased; however, introduction of TEC considerably enhanced the dispersion quality of LDHs. Differential scanning calorimetry results showed that the addition of LDH and TEC had no significant influence on the crystallinity of nanocomposites obtained from solution casting. In contrast, once the samples were cooled from melt, the concurrent use of LDH and TEC led to a dramatic enhancement in the crystallinity of PLA ( X c = 55.5%). Moreover, the LDH nanoparticles counterbalanced the adverse effects of plasticization by TEC leading to enhanced toughness of the final nanocomposites. LDH had also a positive influence on thermal stability of PLA, indicating the heat-insulating role of LDH particles. In conclusion, the concurrent use of LDH and TEC could extend the applicability of PLA especially in food packaging applications.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2346 ◽  
Author(s):  
Stanislav Kotsilkov ◽  
Evgeni Ivanov ◽  
Nikolay Vitanov

Nanoparticles of graphene and carbon nanotubes are attractive materials for the improvement of mechanical and barrier properties and for the functionality of biodegradable polymers for packaging applications. However, the increase of the manufacture and consumption increases the probability of exposure of humans and the environment to such nanomaterials; this brings up questions about the risks of nanomaterials, since they can be toxic. For a risk assessment, it is crucial to know whether airborne nanoparticles of graphene and carbon nanotubes can be released from nanocomposites into the environment at their end-life, or whether they remain embedded in the matrix. In this work, the release of graphene and carbon nanotubes from the poly(lactic) acid nanocomposite films were studied for the scenarios of: (i) biodegradation of the matrix polymer at the disposal of wastes; and (ii) combustion and fire of nanocomposite wastes. Thermogravimetric analysis in air atmosphere, transmission electron microscopy (TEM), atomic force microscopy (AFM) and scanning electron microscope (SEM) were used to verify the release of nanoparticles from nanocomposite films. The three factors model was applied for the quantitative and qualitative risk assessment of the release of graphene and carbon nanotubes from nanocomposite wastes for these scenarios. Safety concern is discussed in respect to the existing regulations for nanowaste stream.


2012 ◽  
Vol 488-489 ◽  
pp. 1393-1397
Author(s):  
Buranin Saengiet ◽  
Wasin Koosomsuan ◽  
Phassakarn Paungprasert ◽  
Rattikarn Khankrua ◽  
Sumonman Naimlang ◽  
...  

The frozen instant food packaging is the one of disposal product, which produced from petroleum–based plastic and has been accumulated worldwide pressuring on the environment. Therefore, the biodegradable plastics have become key candidates in this application. Poly(lactic acid) (PLA) was regarded as one of the most promising biodegradable polymer due to its good mechanical properties. The aim of this work was to study on the freezability and microwavability of PLA through crosslink reaction. For the improvement of the processibility of PLA, hyperbranched polymer (HBP) and polypropylene glycol (PPG) were used as plasticizer. Then the crosslinking of PLA was introduced by addition of peroxide (Luperox101) and triallyl isocyanurate (TAIC) in an internal mixer. Neat and modified PLA samples were characterized and testing for mechanical properties. From the gel content results, it was showed the increased value with the increased content of TAIC due to the denser crosslinked structure of polymer. This result was confirmed by FT-IR spectra. All modified PLA samples showed the higher %strain at break than neat PLA. In addition, impact resistance in frozen state showed the results of modified PLA with 0.1wt% of peroxide and 0.15 wt% of TAIC, was higher than neat PLA. Moreover, this composition also showed the highest microwave response and heat accumulation was suppressed when the specimen was immersed in the water during the test. From the results obtained in this work, the further investigation is needed to pursue and elucidate the relationship between the polymer structure and heat absorption when materials undergo the microwave radiation.


Author(s):  
Ladawan Songtipya ◽  
Thitirat Limchu ◽  
Suphatchara Phuttharak ◽  
Ponusa Songtipya ◽  
Ekwipoo Kalkornsurapranee

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 22 ◽  
Author(s):  
Agueda Sonseca ◽  
Salim Madani ◽  
Gema Rodríguez ◽  
Víctor Hevilla ◽  
Coro Echeverría ◽  
...  

Poly(lactic acid) (PLA) is one of the most commonly employed synthetic biopolymers for facing plastic waste problems. Despite its numerous strengths, its inherent brittleness, low toughness, and thermal stability, as well as a relatively slow crystallization rate represent some limiting properties when packaging is its final intended application. In the present work, silver nanoparticles obtained from a facile and green synthesis method, mediated with chitosan as a reducing and stabilizing agent, have been introduced in the oligomeric lactic acid (OLA) plasticized PLA in order to obtain nanocomposites with enhanced properties to find potential application as antibacterial food packaging materials. In this way, the green character of the matrix and plasticizer was preserved by using an eco-friendly synthesis protocol of the nanofiller. The X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results proved the modification of the crystalline structure as well as the crystallinity of the pristine matrix when chitosan mediated silver nanoparticles (AgCH-NPs) were present. The final effect over the thermal stability, mechanical properties, degradation under composting conditions, and antimicrobial behavior when AgCH-NPs were added to the neat plasticized PLA matrix was also investigated. The obtained results revealed interesting properties of the final nanocomposites to be applied as materials for the targeted application.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4910 ◽  
Author(s):  
Alejandro Aragón-Gutierrez ◽  
Marina P. Arrieta ◽  
Mar López-González ◽  
Marta Fernández-García ◽  
Daniel López

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.


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