Effect of poly(lactic acid) crystallization on its mechanical and heat resistance performances

Ma, Bomou; Wang, Xueli; He, Yong; Dong, Zhen; Zhang, Xu; Xiao, Changfa; Liu, Tianxi

doi:10.1016/j.polymer.2020.123280

Cited by 52 publications

(46 citation statements)

References 48 publications

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“…The temporal evolution of the MSD as a function of time for the matrix polymer (P) at various 𝜖 PT − was presented in Figure 6b, which was obtained from the MD simulations at the equilibrium state through MSD = [R(t) − R(0)] 2 , where the R(t) and R(0) is the position of center-of-mass of MD atoms at time t and 0, respectively. [43] It can be seen from Figure 6b that the value of MSD decreases as the 𝜖 PT − increases at the same time (t), suggesting that stronger attraction between P and T (larger 𝜖 PT − ) would effectively restrict the mobility of the matrix polymer chains to improve the above-mentioned mechanical properties.…”

Section: Resultsmentioning

confidence: 94%

Physical Origin of Distinct Mechanical Properties of Polymer Tethered Graphene Nanosheets Reinforced Polymer Nanocomposites Revealed by Nonequilibrium Molecular Dynamics Simulations

Zhang

Chen

Liu

2021

Macro Theory & Simulations

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A non-equilibrium deformation simulation based on standard molecular dynamics is employed to reveal the physical origin of distinct mechanical properties of polymer nanocomposites (PNCs) reinforced by polymer tethered graphene nanosheets (P/G-T). The effect of tethered polymer length (L) and interaction strength on the mechanical properties, including tensile stress, modulus, and yield strength, are examined. The simulation results show that the P/G-T systems exhibit improved mechanical properties as L and interaction strength increases. The strengthening in attractive interaction between matrix polymer and tethered polymer has a better effect on mechanical properties than that between P and graphene nanosheets. It is found that the bond orientation and nonbonding potential is of crucial importance in determining the mechanical properties of the P/G-T nanocomposite systems. The calculations of radial distribution functions and mean-squared displacement are further performed to reveal the physical origin of enhanced mechanical properties, suggesting that the stronger interfacial interactions will induce the closer packing distance with smaller free volume, higher polymer chain entanglement, and higher restriction of polymer chain movement, which synergistically contribute to the improvement in the mechanical properties. The results may provide useful guidance for promoting the development and practical application of the advanced PNCs with excellent performance.

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Section: Resultsmentioning

confidence: 94%

Physical Origin of Distinct Mechanical Properties of Polymer Tethered Graphene Nanosheets Reinforced Polymer Nanocomposites Revealed by Nonequilibrium Molecular Dynamics Simulations

Zhang

Chen

Liu

2021

Macro Theory & Simulations

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“…The thermal and mechanical stability of PLLA can be improved by enhancing the crystallinity, 20 therefore, the crystallinity of PLLA monofilaments under different annealing conditions were investigated in this study. The glass transition temperature can be observed in the thermal curve of DSC to verify the molecular orientation which affects the tensile properties.…”

Section: Results and Disscuionsmentioning

confidence: 99%

Different properties of poly(L-lactic acid) monofilaments and its corresponding braided springs after constrained and unconstrained annealing

Zhao

et al. 2022

J Biomater Appl

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Thermal annealing is widely applied to enhance the mechanical performance of PLLA monofilaments, which brings in a variety of expected strengths through different constrained methods. In this work, samples with constrained and unconstrained annealing process were both prepared and characterized, including mechanical performance, surface morphology, radial supporting performance and axial flexibility. Experimental results revealed that the monofilaments under constrained annealing showed higher elastic modulus with 6.4 GPa, which were higher than those without any constraint. While the maximal elongation at break with 51.11% were observed in unconstrained annealed monofilaments. Few changes were presented in the molecular weight between the two types of samples. Moreover, the springs under constrained annealing inhibited the most reliable radial supporting performance with higher radial compression force and chronic outward force, 0.665 N/mm and 0.14 N respectively. However, unconstrained annealing springs showed better flexibility with 0.178 N bending stiffness and 1.58 N maximum bending force. These results suggested that filaments and springs with various properties can be obtained under different annealing conditions.

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“…However, the lengthy timescales and nucleation barriers involved in such crystallization events, limited their capture in this atomistic molecular dynamics study. 61,62 Given that recently, coarse-grained molecular dynamics calculations were successfully employed to explore the characterization of such crystallization events in pure PLA, 63 future works extending the use of this computational approach to PLA composites could be of interest.…”

Section: Density Void and Structural Analysesmentioning

confidence: 99%

Molecular-scale exploration of mechanical properties and interactions of poly(lactic acid) with cellulose and chitin

Mileo

Krauter

Sanders

et al. 2022

Preprint

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Poly(lactic acid) (PLA), one of the pillars of the current overarching displacement trend switching from oil- to natural-based polymers is often associated with polysaccharides, to benefit from their increased mechanical properties. This association is, however, greatly hampered by the poor PLA/polysaccharide miscibility, whose underlying nature is still vastly unexplored. This work aims at shedding light into the PLA-polysaccharide interactions and reveal structure-property relationships from a fundamental perspective using atomistic molecular dynamics with amorphous cellulose and chitin as representative polysaccharide molecules. Our computational strategy was able to reproduce targeted mechanical properties of pure and/or composite materials, reveal a lesser degree of immiscibility in PLA/chitin compared to PLA/cellulose associations, assert PLA-oriented polysaccharide reorientations and explore how less effective PLA-polysaccharide hydrogen bonds are related to the poor PLA/polysaccharide miscibility.

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Effect of poly(lactic acid) crystallization on its mechanical and heat resistance performances

Cited by 52 publications

References 48 publications

Physical Origin of Distinct Mechanical Properties of Polymer Tethered Graphene Nanosheets Reinforced Polymer Nanocomposites Revealed by Nonequilibrium Molecular Dynamics Simulations

Physical Origin of Distinct Mechanical Properties of Polymer Tethered Graphene Nanosheets Reinforced Polymer Nanocomposites Revealed by Nonequilibrium Molecular Dynamics Simulations

Different properties of poly(L-lactic acid) monofilaments and its corresponding braided springs after constrained and unconstrained annealing

Molecular-scale exploration of mechanical properties and interactions of poly(lactic acid) with cellulose and chitin

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