Dynamic Mechanical Analysis Investigations of PLA-Based Renewable Materials: How Are They Useful?

Cristea, Mariana; Ionita, Daniela; Iftime, Manuela Maria

doi:10.3390/ma13225302

Cited by 73 publications

(52 citation statements)

References 88 publications

(147 reference statements)

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“…Notably, the highest stiffness was attained with the addition of 2 wt% Joncryl in PLA as compared to 1 wt% Joncryl. This can be attributed to the increase of the molecular weight as discussed previously and as reported in another study as well [58]. It is also believed that the addition of Joncryl in PLA, and especially 2 wt%, has an effect on the adhesion strength between the 3D-printed layers, as seen in the previous sections from the marginal increase of the mechanical tests, as well as from the obtained DMA results.…”

Section: Dynamic Mechanical Analysis (Dma)supporting

confidence: 77%

Influence of Reactive Chain Extension on the Properties of 3D Printed Poly(Lactic Acid) Constructs

et al. 2021

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Fused deposition modeling (FDM) is currently the most popular 3D printing method, where thermoplastic polymers are predominantly used. Among them, the biobased poly(lactic acid) (PLA) governs the FDM filament market, with demand higher than supply, since not all grades of PLA are suitable for FDM filament production. In this work, the effect of a food grade chain extender (Joncryl ADR® 4400) on the physicochemical properties and printability of PLA marketed for injection molding was examined. All samples were characterized in terms of their mechanical and thermal properties. The microstructure of the filaments and 3D-printed fractured surfaces following tensile testing were examined with optical and scanning electron microscopy, respectively. Molecular weight and complex viscosity increased, while the melt flow index decreased after the incorporation of Joncryl, which resulted in filaments of improved quality and 3D-printed constructs with enhanced mechanical properties. Dielectric spectroscopy revealed that the bulk properties of PLA with respect to molecular mobility, both local and segmental, were, interestingly, not affected by the modifier. Indirectly, this may suggest that the major effects of the extender are on chain length, without inducing chain branching, at least not to a significant extent.

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Section: Dynamic Mechanical Analysis (Dma)supporting

confidence: 77%

Influence of Reactive Chain Extension on the Properties of 3D Printed Poly(Lactic Acid) Constructs

et al. 2021

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“…The rapid decrease of the storage modulus at about 60-70 °C is attributed to the glass transition of the PLA [60]. Besides, the increase of storage modulus observed at 90-110 °C is associable to the cold crystallization of PLA [61]. All the filled samples show, as expected, an increase of the modulus value, as compared to their unfilled counterparts, due to the reinforcing effect of the well-dispersed nanofillers [62].…”

Section: Influence Of Screw Profiles and Screw Speedmentioning

confidence: 56%

Rheology, Morphology and Thermal Properties of a PLA/PHB/Clay Blend Nanocomposite: The Influence of Process Parameters

2021

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The effect of process parameters on the final properties of a poly-lactic acid (PLA) and polyhydroxybutyrate (PHB) polymer blend filled with nanoclays was evaluated. To this aim, the nanofilled blend was processed in a co-rotating twin screw extruder, considering three different screw profiles and different values of the screw rotation speed, and the thermal and thermo-mechanical properties of the so-obtained materials were investigated. Furthermore, XRD analyses, SEM observations and rheological characterization were exploited to infer the coupled effect of the process parameters and nanoclay presence on the microstructure of the filled blend. Preliminary thermodynamic calculations allowed predicting the preferential localization of the nanoclay in the interfacial region between the polymeric phases. The relaxation mechanism of the particles of the dispersed phase in nanofilled blend processed, by rheological measurements, is not fully completed due to an interaction between polymer ad filler in the interfacial region with a consequent modification of the blend morphology and, specifically, a development of an enhanced microstructure. Therefore, by varying the screw configuration, particularly the presence of backflow and distribution elements in the screw profile, high shear stresses are induced during the processing able to allow a better interaction between polymers and clay. This finding also occurs in the thermo-mechanical properties of material, as an improvement of storage modulus up to 20% in filled blend processed with a specific screw profile. Otherwise, the microstructure of filled blend processed with different screw speed is similar, according to the other characterizations where no remarkable alterations of materials were detected.

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“…However, the introduction of TPU affects the mobility of molecular chains, which makes the originally tightly arranged molecular chains loose and leads to the decrease of the initial E' of TPU/PDLA/PLLA‐220 48 . And as the processing temperature continues to decrease, the loosely arranged molecular chains do not need higher energy to overcome, which leads to the further decrease of the initial E' of TPU/PDLA/PLLA‐200 and TPU/PDLA/PLLA‐180 49 …”

Section: Resultsmentioning

confidence: 99%

High performance polylactic acid/thermoplastic polyurethane blends with in‐situ fibrillated morphology

Jia

Cao

et al. 2021

J of Applied Polymer Sci

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As an environment‐friendly polyester, polylactic acid (PLA) shows great potential market value. While it still faces some obstacles in large‐scale practical application due to its brittleness. In this work, a novel strategy to improve the toughness of polylactic acid is developed. By adjusting processing temperature during the melt‐blending process, thermoplastic polyurethane/poly (D‐lactic) acid/poly (L‐lactic) acid (TPU/PDLA/PLLA) ternary blends with different morphology are obtained. The experimental results show that the TPU in ternary blends formed a fibrillated micro‐morphology, and the interfacial compatibility between the components is improved when the processing temperature is adjusted to 200°C. Under the synergistic action of in‐situ fibrillated TPU and stereocomplex (SC) crystals, the toughness of the ternary blends is improved significantly without sacrificing its own tensile strength. The maximum value of tensile strength, elongation at break, and fracture work of ternary blends are 61.9 MPa, 23.5%, and 1038.9 kJ/m3, respectively. In addition, the melt strength of ternary blends was significantly improved, which is a benefit to their processing application.

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Dynamic Mechanical Analysis Investigations of PLA-Based Renewable Materials: How Are They Useful?

Cited by 73 publications

References 88 publications

Influence of Reactive Chain Extension on the Properties of 3D Printed Poly(Lactic Acid) Constructs

Influence of Reactive Chain Extension on the Properties of 3D Printed Poly(Lactic Acid) Constructs

Rheology, Morphology and Thermal Properties of a PLA/PHB/Clay Blend Nanocomposite: The Influence of Process Parameters

High performance polylactic acid/thermoplastic polyurethane blends with in‐situ fibrillated morphology

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