Multi-modal commutative dynamics in semi-crystalline polymers undergoing multiple shape memory behavior

Wang, Xiaodong; Lu, Haibao; Gorbacheva, Galina; Hossain, Mokarram; Fu, Yong Qing

doi:10.1088/1361-665x/abe4e5

Cited by 6 publications

(3 citation statements)

References 51 publications

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“…Since the PET is semi-crystalline or amorphous based on the curing condition, the molecules are rigid, with no free volume to stretch. Thus, the PET core sandwich panels produced lesser load absorption, whereas, in PVC, the load could transfer uniformly without crack propagation and cleavage formation [66]. However, the PVC core unit contains composites that offer higher flexural strength.…”

Section: Sandwich Composite Three-point Bendingmentioning

confidence: 99%

RETRACTED: Mechanical Properties Study on Sandwich Composites of Glass Fiber Reinforced Plastics (GFRP) Using Liquid Thermoplastic Resin, Elium®: Preliminary Experiments

et al. 2022

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Composite sandwich structures have been used in high performance applications such as wind turbine blades, due to their unique lightweight structure and superior mechanical properties. In the current study, a new liquid thermoplastic and thermoset resin were used to fabricate four different composite sandwich panels with two various foam types and densities. Composites made with epoxy resin are presented to comprehensively compare the mechanical properties of sandwich structures to elium resin. In the case of the mechanical properties and due to a new liquid thermoplastic resin, extensive comparisons of three-point bending, climbing drum peel, and flatwise tensile strength were investigated and compared with each other. The flexural and flatwise strength of sandwich composite increased by 53% and 75%, respectively, when using Elium resin. Then, the highest value was shown in the GF/PVC/ELIUM structure. The results revealed that Elium resin could be excellent in the case of mechanical properties to replace traditional resins to fabricate various composite structures and manage the challenge of recyclable composites. Elium resin can replace thermoset-based resins for the manufacturing of laminates and composites that are fully recyclable at room temperature with comparable mechanical properties.

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Section: Sandwich Composite Three-point Bendingmentioning

confidence: 99%

RETRACTED: Mechanical Properties Study on Sandwich Composites of Glass Fiber Reinforced Plastics (GFRP) Using Liquid Thermoplastic Resin, Elium®: Preliminary Experiments

et al. 2022

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“…They can sustain large deformation and show responsiveness to multiple stimuli [2,3] . Due to the broad potential applications in biomedical and aerospace areas, SMPs have received considerable attention in the past two decades [4][5][6][7][8][9][10] . The shape-memory effect has been reported and optimized in various polymeric systems to improve the performances of shape fixity and shape recovery [11,12] .…”

Section: Introductionmentioning

confidence: 99%

Shape memory behaviors of 3D printed liquid crystal elastomers

Dai,

Wang,

Chen

et al. 2023

Soft Sci

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As soft active materials, shape-memory polymers (SMPs) and liquid crystal elastomers (LCEs) have attracted considerable research interest due to their potential applications in various areas. SMPs refer to polymeric materials that can return to their permanent shape in response to external stimuli, such as heat, light, and solvent. In this sense, LCEs can exhibit intrinsic shape-memory behaviors since LCEs can switch between two shapes with temperature change due to the order-disorder transition of liquid crystals. In this work, we fabricate both the polydomain and monodomain nematic LCEs through direct ink writing 3D printing. With increasing the temperature of the substrates, the printed LCEs change from the monodomain state to the polydomain state. For polydomain LCEs, a reversible shape change can occur upon constant loading, while the monodomain can switch the shape with temperature in the stress-free state. This two-way shape-memory behavior is caused by the nematic-isotropic phase transition. We further show that the printed LCEs exhibit a good one-way shape-memory effect due to glass transition. The shape recovery region increases with the programming temperature, which is a typical temperature memory effect. Finally, it is demonstrated that complex shape-memory performance can be designed by combining one-way and two-way shape-memory effects. Specifically, for the monodomain LCEs, with increasing temperature, the programmed shape first recovers, and a second shape change can further occur due to the nematic-isotropic transition.

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“…Based on an extensive literature, we found that the combination of crystal phases and CANs has resulted in significant improvements in the mechanical performance of the semicrystalline thermoset epoxy [30]. However, the self-healing and toughening mechanisms behind these phenomena have not been fully understood, and both theoretical models and experimental studies are urgently needed.…”

Section: Introductionmentioning

confidence: 99%

A Hamiltonian graph model for the cooperative toughening of crystalline phases and covalent adaptable networks in semi-crystalline thermoset epoxy

Zhang

Elmarakbi

et al. 2023

Smart Mater. Struct.

Self Cite

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Attributed to its existence of bond exchange reactions (BERs) and covalent adaptable networks (CANs), thermoset epoxy has shown self-healing and reversibly mechanical capabilities. However, toughening mechanisms and cooperative coupling of these crystal phases and CANs in a semi-crystalline thermoset epoxy have not been well understood. In this study, a Hamiltonian graph model is formulated to explore toughening mechanisms in the semi-crystalline thermoset epoxy based on the vertices and paths, both of which are employed to describe the crystalline phases and CANs, respectively. A free-energy equation is further developed based on the tail and tie free energy functions to investigate the cooperative coupling of crystal phases and CANs. The crystal phases increase the cross-linking density of the CANs, which help the crystal phases with a homogeneous dispersion. Moreover, an extended Maxwell model is developed along with the Hamiltonian graph to explore the coupling effect of crystal phase and CAN on the mechanical behaviors of semi-crystalline thermoset epoxy. A constitutive stress-strain relationship is then proposed to describe the self-healing and toughening behaviors of semi-crystalline thermoset epoxy. The stress-strain relationship of semi-crystalline polymers, which incorporates the crystal phases and CANs, has been thoroughly investigated using the analytical results obtained from the proposed Hamiltonian graph model. Finally, effectiveness of the proposed model is verified using the finite element analysis and a set of experimental data.

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Multi-modal commutative dynamics in semi-crystalline polymers undergoing multiple shape memory behavior

Cited by 6 publications

References 51 publications

RETRACTED: Mechanical Properties Study on Sandwich Composites of Glass Fiber Reinforced Plastics (GFRP) Using Liquid Thermoplastic Resin, Elium®: Preliminary Experiments

RETRACTED: Mechanical Properties Study on Sandwich Composites of Glass Fiber Reinforced Plastics (GFRP) Using Liquid Thermoplastic Resin, Elium®: Preliminary Experiments

Shape memory behaviors of 3D printed liquid crystal elastomers

A Hamiltonian graph model for the cooperative toughening of crystalline phases and covalent adaptable networks in semi-crystalline thermoset epoxy

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