Compounding and Melt Strengthening of Poly(Lactic Acid): Shear and Elongation Rheological Investigations for Forming Process

2013 ◽  
Vol 554-557 ◽  
pp. 1751-1756 ◽  
Author(s):  
Benoit Mallet ◽  
Khalid Lamnawar ◽  
Abderrahim Maazouz
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Supercritical Co2 ◽  
Food Packaging ◽  
Blow Up ◽  
Good Alternative ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Forming Process ◽  
Batch Foaming

The poly (lactic acid) (PLA), through its organic origin and its biodegradation properties, can be a good alternative to petroleum-based polymers. To this end, the forming process as well blown extrusion and foaming of PLA was investigated in this study as an alternative for the production of food packaging. Through this work, we present some promising routes to enhance its processing ability which presents several challenges mainly due to the poor shear and elongation properties of this biopolymer. To our knowledge, there is no paper dedicated to the investigation of foaming and/or blown extrusion of PLA that involves structural, rheological and thermo-mechanical properties. To achieve this objective, various formulations of PLA with multifunctionalized epoxy, nucleants and plasticizer were prepared and characterized on the basis of their linear viscoelasticity and extensional properties. The balance of chain extension and branching has been also investigated using solution viscosimetry, Steric exclusion chromatography (SEC) and rheology (relaxation spectrum, Van Gurp Palmen curves….). We pushed further by characterizing both the structure and thermo-mechanical properties of PLA formulations. On one hand, a batch foaming assisted with supercritical CO2 was achieved following a full characterization in physicochemical, rheological and thermal domain, The influence of the foaming parameters, the extent of chain modification as well as the contribution of crystallization on cell morphology was evaluated. Based on these parameters, structures ranging from micro to macro-cellular-cell were obtained. On the other hand, the stability maps of blown processing for neat and modified PLA were established at different die temperatures. We have achieved a great enhancement of the blown processing windows of PLA with high BUR (Blow Up Ratio) and TUR (Take Up Ratio) attained. We were able to demonstrate that a higher kinetic of crystallization can also be reached for chain-extended and branched PLA formulated with adequate amounts of nucleants and plasticizers. Induced crystallization during process was also demonstrated. Through this work, blown films with interesting thermo-mechanical and mechanical properties have been produced using an optimal formulation for PLA. References [1] A. Maazouz, K. Lamnawar, B. Mallet, Patent: C08L67/00; C08J5/10. FR2941702 (A1). (2010) [2] Y.-M. Corre, A. Maazouz, J. Duchet, J. Reignier, Batch foaming of chain extended PLA with supercritical CO2: Influence of the rheological properties and the process parameters on the cellular structure. J. of Supercritical Fluids,58 (2011) 177-188 [3] B. Mallet, K. Lamnawar, A. Maazouz, Compounding and processing of biodegradable materials based on PLA for packaging applications: In greening the 21st century material’s world, Frontiers in Science and Engineering, 1-2(2011) 1-44 [4] B. Mallet, K. Lamnawar, A. Maazouz, Improvement of blown extrusion processing of PLA: structure-processing-properties relashionships. Polymer engineering and Science (To appear in 2013).

Response of Modified Poly(lactic acid) to Microwave Radiation

2012 ◽  
Vol 488-489 ◽  
pp. 1393-1397
Author(s):  
Buranin Saengiet ◽  
Wasin Koosomsuan ◽  
Phassakarn Paungprasert ◽  
Rattikarn Khankrua ◽  
Sumonman Naimlang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Microwave Radiation ◽  
Food Packaging ◽  
Impact Resistance ◽  
Poly Lactic Acid ◽  
Polypropylene Glycol ◽  
Heat Accumulation ◽  
The One ◽  
Internal Mixer

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.

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.

scholarly journals Melt strengthening of polylactic acid and its blends: Shear and elongation rheological investigations of the forming process

2021 ◽  
Author(s):  
Abderrahim Maazouz ◽  
Khalid Lamnawar
Keyword(s):  
Polylactic Acid ◽  
Blow Up ◽  
Good Alternative ◽  
Thermomechanical Properties ◽  
Chain Extension ◽  
Nucleating Agents ◽  
Forming Process ◽  
Exclusion Chromatography ◽  
Stability Maps ◽  
The Stability

Polylactic acid (PLA) can be a good alternative to petroleum-based polymers thanks to its organic origin and its biodegradability. This study introduces some promising routes for enhancing the processability of PLA, which presents several challenges due mainly to the poor shear and elongation properties of this biopolymer. To our knowledge, this is the first paper dedicated to an investigation of foaming and/or blown extrusion of PLA that focuses on structural, rheological and thermomechanical properties. Two main routes were selected: (i) the modification of its structural, rheological and thermomechanical properties and (ii) blending the PLA with another ductile, thermoplastic biopolymer such as poly (butylene adipate-co-terephthalate) (PBAT) or polyamide (PA11). Various formulations of PLA with multifunctionalized epoxy, nucleating agents and plasticizer were prepared and characterized on the basis of their linear viscoelasticity and extensional properties. The balance of chain extension and branching was also investigated using solution viscosimetry, steric exclusion chromatography (SEC) and rheology (shear and elongation rheology). On one hand, a batch foaming process assisted by supercritical CO2 was carried out. The influence of the foaming parameters, the extent of chain modification and the contribution of crystallization to cell morphology were all evaluated. Based on these parameters, structures ranging from micro to macro-cellular-cell were obtained. On the other hand, the stability maps of blown extrusion for neat and modified PLA were established at different die temperatures. We succeeded in greatly enhancing the blown extrusion windows of PLA, achieving high blow-up ratio (BUR) and take-up ratio (TUR) values. We were able to demonstrate that faster kinetics of crystallization can also be reached for chain-extended and branched PLA formulated with adequate amounts of nucleating agents and plasticizers. Through this work, blown films with intriguing thermomechanical and mechanical properties were produced using an optimal formulation for PLA. 

Thermomechanical Study and Thermal Behavior of Plasticized Poly(Lactic Acid) Nanocomposites

2021 ◽  
Vol 317 ◽  
pp. 333-340
Author(s):  
Mohammed Zorah ◽  
Izan Roshawaty Mustapa ◽  
Norlinda Daud ◽  
Nahida Jumah ◽  
Nur Ain Syafiqah Sudin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Lactic Acid ◽  
Thermal Behavior ◽  
Food Packaging ◽  
Mechanical Performance ◽  
Poly Lactic Acid ◽  
Solvent Casting ◽  
Thermal And Mechanical Properties ◽  
Hot Press

Poly (lactic acid) (PLA) is a useful alternative to petrochemical commodity material used in such as in food packaging industries. Due to its inherent brittleness, low thermal stability, and poor crystallization, it needs to improve its properties, namely in terms of thermal and mechanical performance. The plasticized PLA composites reinforced with nanofiller were prepared by solvent casting and hot press methods. Thermal and mechanical properties, as well as the crystallinity study of these nanocomposites, were investigated to study the effect of tributyl citrate (TBC) and TiO2 on the PLA composites. The addition of TBC improved the flexibility and crystallinity of the composites. Reinforcement of TiO2 was found as a practical approach to improve the mechanical properties, thermal stability, and enhanced crystalline ability for plasticized PLA nanocomposites. Based on the results achieved in this study, the composite with 3.5% nanofiller (pPLATi3.5) presented the optimum set of mechanical properties and improved thermal stability.

Mechanical Properties of Biocomposite Films Based on Poly(Lactic Acid) Reinforced with Cellulose Fibers

2018 ◽  
Vol 280 ◽  
pp. 410-414
Author(s):  
T. Jamnongkan ◽  
N. Boonjuban ◽  
J. Sangkhachat ◽  
A. Wattanakornsiri ◽  
Rattanaphol Mongkholrattanasit
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Cellulose Fiber ◽  
Cellulose Fibers ◽  
Good Alternative ◽  
Swelling Behavior ◽  
Poly Lactic Acid ◽  
Alternative Reinforcement ◽  
Biocomposite Films ◽  
Biopolymer Composites

In this paper, we intended to study and improve the mechanical properties of poly (lactic acid) (PLA) composites with cellulose fibers from recycled newspapers. The influence of cellulose fiber content on tensile mechanical properties and swelling behavior of biocomposite films were investigated. In addition, the morphological property of biocomposite films was determined by scanning electron microscopy (SEM). It was found that the cellulose fibers have directly affected to the swelling behavior of biocomposite films. In addition, it was found that the cellulose fibers were found embedded between PLA matrices, which resulting to the improvement and increase the mechanical properties of biocomposite films. These findings illustrate that the cellulose fibers from recycled newspaper possesses good fillers and could be a good alternative reinforcement for biopolymer composites.

scholarly journals Poly(lactic Acid): A Versatile Biobased Polymer for the Future with Multifunctional Properties—From Monomer Synthesis, Polymerization Techniques and Molecular Weight Increase to PLA Applications

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1822
Author(s):  
Evangelia Balla ◽  
Vasileios Daniilidis ◽  
Georgia Karlioti ◽  
Theocharis Kalamas ◽  
Myrika Stefanidou ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Plastic Pollution ◽  
Practical Applications ◽  
Decomposition Reactions ◽  
Melt Polycondensation ◽  
Polymerization Conditions ◽  
Molecular Weight Increase

Environmental problems, such as global warming and plastic pollution have forced researchers to investigate alternatives for conventional plastics. Poly(lactic acid) (PLA), one of the well-known eco-friendly biodegradables and biobased polyesters, has been studied extensively and is considered to be a promising substitute to petroleum-based polymers. This review gives an inclusive overview of the current research of lactic acid and lactide dimer techniques along with the production of PLA from its monomers. Melt polycondensation as well as ring opening polymerization techniques are discussed, and the effect of various catalysts and polymerization conditions is thoroughly presented. Reaction mechanisms are also reviewed. However, due to the competitive decomposition reactions, in the most cases low or medium molecular weight (MW) of PLA, not exceeding 20,000–50,000 g/mol, are prepared. For this reason, additional procedures such as solid state polycondensation (SSP) and chain extension (CE) reaching MW ranging from 80,000 up to 250,000 g/mol are extensively investigated here. Lastly, numerous practical applications of PLA in various fields of industry, technical challenges and limitations of PLA use as well as its future perspectives are also reported in this review.

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
Keyword(s):  
Lactic Acid ◽  
Numerical Modelling ◽  
Temperature Profile ◽  
Food Packaging ◽  
Strong Dependence ◽  
Viscoelastic Model ◽  
Poly Lactic Acid ◽  
Strain History ◽  
Optimal Temperature ◽  
Broad Perspective

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.

Conductivity and mechanical properties of carbon black-reinforced poly(lactic acid) (PLA/CB) composites

2021 ◽  
Author(s):  
Jipeng Guo ◽  
Chi-Hui Tsou ◽  
Yongqi Yu ◽  
Chin-San Wu ◽  
Xuemei Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Carbon Black ◽  
Poly Lactic Acid

scholarly journals A Review: Research Progress in Modification of Poly (Lactic Acid) by Lignin and Cellulose

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 776
Author(s):  
Sixiang Zhai ◽  
Qingying Liu ◽  
Yuelong Zhao ◽  
Hui Sun ◽  
Biao Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Composite Materials ◽  
Crystallization Rate ◽  
Research Progress ◽  
Poly Lactic Acid ◽  
Green Composite ◽  
Materials Development ◽  
Research Attention ◽  
Biomass Components

With the depletion of petroleum energy, the possibility of prices of petroleum-based materials increasing, and increased environmental awareness, biodegradable materials as a kind of green alternative have attracted more and more research attention. In this context, poly (lactic acid) has shown a unique combination of properties such as nontoxicity, biodegradability, biocompatibility, and good workability. However, examples of its known drawbacks include poor tensile strength, low elongation at break, poor thermal properties, and low crystallization rate. Lignocellulosic materials such as lignin and cellulose have excellent biodegradability and mechanical properties. Compounding such biomass components with poly (lactic acid) is expected to prepare green composite materials with improved properties of poly (lactic acid). This paper is aimed at summarizing the research progress of modification of poly (lactic acid) with lignin and cellulose made in in recent years, with emphasis on effects of lignin and cellulose on mechanical properties, thermal stability and crystallinity on poly (lactic acid) composite materials. Development of poly (lactic acid) composite materials in this respect is forecasted.

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.

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