Functionalized Cellulose Nanocrystals for Improving the Mechanical Properties of Poly(Lactic Acid)

2018 ◽  
Author(s):  
Jamileh Shojaeiarani ◽  
Dilpreet Bajwa
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Cellulose Nanocrystals ◽  
Mechanical Test ◽  
Poly Lactic Acid ◽  
Injection Molding Process ◽  
Molding Process ◽  
Dynamic Mechanical ◽  
Uniform Dispersion ◽  
The Impact

Biopolymers are emerging materials with numerous capabilities of minimizing the environmental hazards caused by synthetic materials. The competitive mechanical properties of bio-based poly(lactic acid) (PLA) reinforced with cellulose nanocrystals (CNCs) have attracted a huge interest in improving the mechanical properties of the corresponding nanocomposites. To obtain optimal properties of PLA-CNC nanocomposites, the compatibility between PLA and CNCs needs to be improved through uniform dispersion of CNCs into PLA. The application of chemical surface functionalization technique is an essential step to improve the interaction between hydrophobic PLA and hydrophilic CNCs. In this study, a combination of a time-efficient esterification technique and masterbatch approach was used to improve the CNCs dispersibility in PLA. Nanocomposites reinforced by 1, 3, and 5 wt% functionalized CNCs were prepared using twin screw extrusion followed by injection molding process. The mechanical and dynamic mechanical properties of pure PLA and nanocomposites were studied through tensile, impact and dynamic mechanical analysis. The impact fractured surfaces were characterized using scanning electron microscopy. The mechanical test results exhibited that tensile strength and modulus of elasticity of nanocomposites improved by 70% and 11% upon addition of functionalized CNCs into pure PLA. The elongation at break and impact strength of nanocomposites exhibited 43% and 35% increase as compared to pure PLA. The rough and irregular fracture surface in nanocomposites confirmed the higher ductility in PLA nanocomposites as compared to pure PLA. The incorporation of functionalized CNCs into PLA resulted in an increase in storage modulus and a decrease in tan δ intensity which was more profound in nanocomposites reinforced with 3 wt% functionalized CNCs.

scholarly journals Poly(Lactic Acid)–Poly(Butylene Succinate)–Sugar Beet Pulp Composites; Part I: Mechanics of Composites with Fine and Coarse Sugar Beet Pulp Particles

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2531
Author(s):  
Rodion Kopitzky
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Sugar Beet ◽  
Cell Structure ◽  
Sugar Beet Pulp ◽  
Poly Lactic Acid ◽  
Butylene Succinate ◽  
Fracture Patterns ◽  
Beet Pulp ◽  
The Impact

Sugar beet pulp (SBP) is a residue available in large quantities from the sugar industry, and can serve as a cost-effective bio-based and biodegradable filler for fully bio-based compounds based on bio-based polyesters. The heterogeneous cell structure of sugar beet suggests that the processing of SBP can affect the properties of the composite. An “Ultra-Rotor” type air turbulence mill was used to produce SBP particles of different sizes. These particles were processed in a twin-screw extruder with poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) and fillers to granules for possible marketable formulations. Different screw designs, compatibilizers and the use of glycerol as a thermoplasticization agent for SBP were also tested. The spherical, cubic, or ellipsoidal-like shaped particles of SBP are not suitable for usage as a fiber-like reinforcement. In addition, the fineness of ground SBP affects the mechanical properties because (i) a high proportion of polar surfaces leads to poor compatibility, and (ii) due to the inner structure of the particulate matter, the strength of the composite is limited to the cohesive strength of compressed sugar-cell compartments of the SBP. The compatibilization of the polymer–matrix–particle interface can be achieved by using compatibilizers of different types. Scanning electron microscopy (SEM) fracture patterns show that the compatibilization can lead to both well-bonded particles and cohesive fracture patterns in the matrix. Nevertheless, the mechanical properties are limited by the impact and elongation behavior. Therefore, the applications of SBP-based composites must be well considered.

Influence of temperature dependence on the structural characteristics of polyoxymethylene/poly(lactic acid) blends by injection molding

2019 ◽  
Vol 39 (10) ◽  
pp. 944-953
Author(s):  
Jitlada Boonlertsamut ◽  
Suchalinee Mathurosemontri ◽  
Supaphorn Thumsorn ◽  
Toshikazu Umemura ◽  
Atsushi Sakuma
Keyword(s):  
Lactic Acid ◽  
Injection Molding ◽  
Crystal Size ◽  
Structural Characteristics ◽  
Growth Direction ◽  
Poly Lactic Acid ◽  
Injection Molding Process ◽  
Mechanical And Thermal Properties ◽  
Molding Process ◽  
Microscopy Images

Abstract In this research, different strategies to modify the structure of polymer blends were investigated with the objective of adjusting the composition of polyoxymethylene (POM) and poly(lactic acid) (PLA) under typical processing conditions. POM shows a good balance of mechanical and thermal properties. However, this polymer is obtained from petrochemical sources, and in some markets, environmentally friendly materials are important. Blending POM with PLA preserves the advantages of POM while ensuring the bio-based content of PLA. POM/PLA blends were prepared by an injection molding process with various injection speeds of 10, 50, 100, and 1000 mm/s to ensure high ductility. Mechanical property analysis showed that the PLA content and processing temperatures are highly effective in modifying the stiffness of POM/PLA blends. The effect of crystallization on POM/PLA blends was assessed by varying the annealing time. High-magnification scanning electron microscopy images revealed that the gaps between fibrillar regions represent the growth direction of the PLA phase before it was removed. This was evidence for the effect of PLA on the crystallization of POM. The crystal size and crystalline volume also affected the structural characteristics of POM/PLA blends.

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 Interfacial Adhesive Strength of Two Layered Polyoxymethylene/Poly (lactic acid) Molding by a Simultaneous Composite Injection Molding Process

Seikei-Kakou ◽  
2011 ◽  
Vol 23 (9) ◽  
pp. 561-567
Author(s):  
Satoshi Nagai ◽  
Akira Itou ◽  
Wongsriraksa Patcharat ◽  
Supaporn Thumsorn ◽  
Yew Wei Leong ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Injection Molding ◽  
Adhesive Strength ◽  
Poly Lactic Acid ◽  
Injection Molding Process ◽  
Molding Process

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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