Thermal, rheological and morphological properties of poly (lactic acid) (PLA) and talc composites

Cipriano, Talita Ferreira; Silva, Ana Lúcia Nazareth da; Silva, Antônio Henrique da Fonseca Thomé da Monteiro; Sousa, Atos Alves de; Silva, Gustavo Monteiro da; Rocha, Marisa Cristina Guimarães

doi:10.4322/polimeros.2014.067

Cited by 60 publications

(16 citation statements)

References 21 publications

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“…Thermal parameters obtained during the heating process are shown in Table 2. Control PLA film showed a glass transition around 64 • C and a crystal rearrangement at 117.8 • C. An endothermic transition with double melting peaks at 149.4 and 154.4 • C, characteristic peaks of this type of semicrystalline polymers, was detected due to the presence of crystals with different morphologies or lamellar thicknesses formed during crystallization of the material and cold rearrangement [38,39]. Table 2.…”

Section: Differential Scanning Calorimetrymentioning

confidence: 97%

Development of Bilayer Biodegradable Composites Containing Cellulose Nanocrystals with Antioxidant Properties

et al. 2019

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The interest in the development of novel biodegradable composites has increased over last years, and multilayer composites allow the design of materials with functionality and improved properties. In this work, bilayer structures based on a coated zein layer containing quercetin and cellulose nanocrystals (CNC) over an extruded poly(lactic acid) (PLA) layer were developed and characterized. Bilayer composites were successfully obtained and presented a total thickness of approx. 90 µm. The coated zein layer and quercetin gave a yellowish tone to the composites. The incorporation of the zein layer containing CNC decreased the volatile release rate during thermal degradation. Regarding to mechanical properties, bilayer composites presented lower brittleness and greater ductility evidenced by a lower Young’s modulus and higher elongation values. Water permeability values of bilayer composites greatly increased with humidity and the zein coated layer containing quercetin increased this effect. Experimental data of quercetin release kinetics from bilayer structures indicated a higher release for an alcoholic food system, and the incorporation of cellulose nanocrystals did not influence the quercetin diffusion process.

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Section: Differential Scanning Calorimetrymentioning

confidence: 97%

Development of Bilayer Biodegradable Composites Containing Cellulose Nanocrystals with Antioxidant Properties

et al. 2019

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“…Nucleation of polymer depends on the properties of the nucleating agent used, such as particle size, geometry, surface structure, and interfacial interactions with the polymer matrix [ 8 ]. Several studies have been conducted to identify the effective nucleating agent for PLA, such as graphene [ 7 , 9 ], talc [ 10 , 11 , 12 ], and natural fiber [ 13 , 14 , 15 , 16 ]. Generally, smaller particles make a more effective nucleating agent than larger particles due to their large specific surface areas [ 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Functionality of Cellulose Nanofiber as Bio-Based Nucleating Agent and Nano-Reinforcement Material to Enhance Crystallization and Mechanical Properties of Polylactic Acid Nanocomposite

et al. 2021

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Polylactic acid (PLA), a potential alternative material for single use plastics, generally portrays a slow crystallization rate during melt-processing. The use of a nanomaterial such as cellulose nanofibers (CNF) may affect the crystallization rate by acting as a nucleating agent. CNF at a certain wt.% has been evidenced as a good reinforcement material for PLA; nevertheless, there is a lack of information on the correlation between the amount of CNF in PLA that promotes its functionality as reinforcement material, and its effect on PLA nucleation for improving the crystallization rate. This work investigated the nucleation effect of PLA incorporated with CNF at different fiber loading (1–6 wt.%) through an isothermal and non-isothermal crystallization kinetics study using differential scanning calorimetry (DSC) analysis. Mechanical properties of the PLA/CNF nanocomposites were also investigated. PLA/CNF3 exhibited the highest crystallization onset temperature and enthalpy among all the PLA/CNF nanocomposites. PLA/CNF3 also had the highest crystallinity of 44.2% with an almost 95% increment compared to neat PLA. The highest crystallization rate of 0.716 min–1 was achieved when PLA/CNF3 was isothermally melt crystallized at 100 °C. The crystallization rate was 65-fold higher as compared to the neat PLA (0.011 min–1). At CNF content higher than 3 wt.%, the crystallization rate decreased, suggesting the occurrence of agglomeration at higher CNF loading as evidenced by the FESEM micrographs. In contrast to the tensile properties, the highest tensile strength and Young’s modulus were recorded by PLA/CNF4 at 76.1 MPa and 3.3 GPa, respectively. These values were, however, not much different compared to PLA/CNF3 (74.1 MPa and 3.3 GPa), suggesting that CNF at 3 wt.% can be used to improve both the crystallization rate and the mechanical properties. Results obtained from this study revealed the dual function of CNF in PLA nanocomposite, namely as nucleating agent and reinforcement material. Being an organic and biodegradable material, CNF has an increased advantage for use in PLA as compared to non-biodegradable material and is foreseen to enhance the potential use of PLA in single use plastics applications.

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“…The isolated effect of BN has been demonstrated in a study on PHBV/bamboo pulp fibre (20 wt%) composites, where the addition of BN promoted nucleation and crystallisation of PHBV, as evidenced by an increase in the crystallisation temperature [19]. 4 Apart from being used as a nucleating agent, talc has also been used alone or in combination with other fillers as reinforcement for PP [20][21][22] and poly(lactic acid) (PLA) [23,24], to improve their melt strength and stiffness. It has also been used as an additive to aid processing [25] and as a post processing step to improve the surface quality of the final product [26].…”

Section: Introductionmentioning

confidence: 99%

Mechanical performance and long-term indoor stability of polyhydroxyalkanoate (PHA)-based wood plastic composites (WPCs) modified by non-reactive additives

Chan

Vandi

Pratt

et al. 2018

European Polymer Journal

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This study aims to understand the material properties and long-term indoor stability of a biocomposite based on pine wood flour and poly(3-hydroxybutyrate-co-3hydroxyvalerate) (PHBV) modified by a nucleating agent, boron nitride (BN), and an inorganic filler, talc, and to develop knowledge of the linkage between the microscalestructure and mechanical properties. Both BN, at a loading of 1 wt% and talc, at 5 wt%, had a nucleating effect on polymer crystallisation, with BN being more effective as evidenced by Avrami kinetic analysis. The addition of 5 and 10 wt% of talc enhanced the tensile strength of the PHBV/wood flour (50/50 wt%) composite from 22.3 ± 1.3 2 MPa (mean ± 95% confidence interval) to 24.3 ± 0.6 MPa and 24.7 ± 0.9 MPa respectively. The tensile modulus was also improved from 5.6 ± 0.6 GPa to 6.9 ± 0.4 GPa and 8.1 ± 0.7 GPa respectively. The micron-sized talc may fill voids within the composite matrix and/or act as an alternate filler, altering the deformation mechanism.However, the level of improvement in modulus was reduced after 1 year of conditioned ageing under a controlled environment (20 o C, 50% humidity). It is proposed that the combined effects of the swelling of wood through moisture uptake, the shrinkage of PHBV through secondary crystallisation, and the localised stress around talc particles led to weakened talc-PHBV interfaces. KeywordsPolyhydroxyalkanoate (PHA); Wood flour; Wood polymer composites; Talc; Mechanical properties; Indoor stability 1. Highlights  BN and talc increases the rate of crystallisation of the wood-PHBV composites.  Wood-PHA composites are mechanical stable at ambient temperature for at least 1 year.  Talc offers complementary space-filling morphology and improves composite stiffness. The level of stiffness improvement from talc is reduced after 1-year of ageing. A mechanism for the weakened talc-PHBV interface upon ageing is proposed.

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Thermal, rheological and morphological properties of poly (lactic acid) (PLA) and talc composites

Cited by 60 publications

References 21 publications

Development of Bilayer Biodegradable Composites Containing Cellulose Nanocrystals with Antioxidant Properties

Development of Bilayer Biodegradable Composites Containing Cellulose Nanocrystals with Antioxidant Properties

Functionality of Cellulose Nanofiber as Bio-Based Nucleating Agent and Nano-Reinforcement Material to Enhance Crystallization and Mechanical Properties of Polylactic Acid Nanocomposite

Mechanical performance and long-term indoor stability of polyhydroxyalkanoate (PHA)-based wood plastic composites (WPCs) modified by non-reactive additives

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