Shape Memory Behavior of PET Foams

Santo, Loredana; Bellisario, Denise; Quadrini, Fabrizio

doi:10.3390/polym10020115

Cited by 18 publications

(22 citation statements)

References 18 publications

(18 reference statements)

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“…Regardless of the matrix constituent (polymeric, metallic, or ceramic material), cellular materials (CMs) are ideal energy absorbers. This feature of the FMs is highlighted by the appearance of a large flat/hardening plateau region (up to 70% strain) at almost constant stress [9,10,11].…”

Section: Introductionmentioning

confidence: 99%

Compressive Behavior of Aluminum Microfibers Reinforced Semi-Rigid Polyurethane Foams

2018

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Unreinforced and reinforced semi-rigid polyurethane (PU) foams were prepared and their compressive behavior was investigated. Aluminum microfibers (AMs) were added to the formulations to investigate their effect on mechanical properties and crush performances of closed-cell semi-rigid PU foams. Physical and mechanical properties of foams, including foam density, quasi-elastic gradient, compressive strength, densification strain, and energy absorption capability, were determined. The quasi-static compression tests were carried out at room temperature on cubic samples with a loading speed of 10 mm/min. Experimental results showed that the elastic properties and compressive strengths of reinforced semi-rigid PU foams were increased by addition of AMs into the foams. This increase in properties (61.81%-compressive strength and 71.29%-energy absorption) was obtained by adding up to 1.5% (of the foam liquid mass) aluminum microfibers. Above this upper limit of 1.5% AMs (e.g., 2% AMs), the compressive behavior changes and the energy absorption increases only by 12.68%; while the strength properties decreases by about 14.58% compared to unreinforced semi-rigid PU foam. The energy absorption performances of AMs reinforced semi-rigid PU foams were also found to be dependent on the percentage of microfiber in the same manner as the elastic and strength properties.

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Section: Introductionmentioning

confidence: 99%

Compressive Behavior of Aluminum Microfibers Reinforced Semi-Rigid Polyurethane Foams

2018

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“…Therefore, the key is to achieve PBT foams with uniform foam morphology and low foam density without sacrificing compressive strength and stiffness. It is well known that the compressive strength is affected by foam density [ 63 ], foam morphology including cell size and cell size distribution [ 64 ], degree of crystallinity [ 65 ] and open-cell content [ 63 ]. In the case of foams nucleated by fiber like additives such as BTAs, the intrinsic reinforcing effect of the additive must be also considered.…”

Section: Resultsmentioning

confidence: 99%

Low-Density Polybutylene Terephthalate Foams with Enhanced Compressive Strength via a Reactive-Extrusion Process

et al. 2020

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Due to their appealing properties such as high-temperature dimensional stability, chemical resistance, compressive strength and recyclability, new-generation foams based on engineering thermoplastics such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) have been gaining significant attention. Achieving low-density foams without sacrificing the mechanical properties is of vital importance for applications in the field of transportation and construction, where sufficient compressive strength is desired. In contrast to numerous research studies on PET foams, only a limited number of studies on PBT foams and in particular, on extruded PBT foams are known. Here we present a novel route to extruded PBT foams with densities as low as 80 kg/m3 and simultaneously with improved compressive properties manufactured by a tandem reactive-extrusion process. Improved rheological properties and therefore process stability were achieved using two selected 1,3,5-benzene-trisamides (BTA1 and BTA2), which are able to form supramolecular nanofibers in the PBT melt upon cooling. With only 0.08 wt % of BTA1 and 0.02 wt % of BTA2 the normalized compressive strength was increased by 28% and 15%, respectively. This improvement is assigned to the intrinsic reinforcing effect of BTA fibers in the cell walls and struts.

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“…Results show that negligible effects are present for the SMPC laminate of the skin at least for limited number of cycles if the elastic range is not crossed during the memory steps. In the case of foams, a training effect may be also observed at the first cycle [ 39 ].…”

Section: Methodsmentioning

confidence: 99%

Shape Memory Composite Sandwich Structures with Self-Healing Properties

et al. 2021

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In this study, Polyurea/Formaldehyde (PUF) microcapsules containing Dicyclopentadiene (DCPD) as a healing substance were fabricated in situ and mixed at relatively low concentrations (<2 wt%) with a thermosetting polyurethane (PU) foam used in turn as the core of a sandwich structure. The shape memory (SM) effect depended on the combination of the behavior of the PU foam core and the shape memory polymer composite (SMPC) laminate skins. SMPC laminates were manufactured by moulding commercial carbon fiber-reinforced (CFR) prepregs with a SM polymer interlayer. At first, PU foam samples, with and without microcapsules, were mechanically tested. After, PU foam was inserted into the SMPC sandwich structure. Damage tests were carried out by compression and bending to deform and break the PU foam cells, and then assess the structure self-healing (SH) and recovery capabilities. Both SM and SH responses were rapid and thermally activated (120 °C). The CFR-SMPC skins and the PU foam core enable the sandwich to exhibit excellent SM properties with a shape recovery ratio up to 99% (initial configuration recovery). Moreover, the integration of microcapsules (0.5 wt%) enables SH functionality with a structural restoration up to 98%. This simple process makes this sandwich structure ideal for different industrial applications.

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Shape Memory Behavior of PET Foams

Cited by 18 publications

References 18 publications

Compressive Behavior of Aluminum Microfibers Reinforced Semi-Rigid Polyurethane Foams

Compressive Behavior of Aluminum Microfibers Reinforced Semi-Rigid Polyurethane Foams

Low-Density Polybutylene Terephthalate Foams with Enhanced Compressive Strength via a Reactive-Extrusion Process

Shape Memory Composite Sandwich Structures with Self-Healing Properties

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