scholarly journals Swelling Resistance and Water-Induced Shape Memory Performances of Sisal Cellulose Nanofibers/Polyethylene Glycol/Citric Acid Nanocellulose Papers

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Zuocai Zhang ◽  
Yuqi Li ◽  
Laifu Song ◽  
Li Ren ◽  
Xu Xu ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Citric Acid ◽  
Shape Memory ◽  
Self Assembly ◽  
Memory Performance ◽  
Cellulose Nanofibers ◽  
Tensile Modulus ◽  
Response Speed ◽  
Shape Memory Materials ◽  
Water Swelling

In this work, a kind of nanocomposite paper was obtained by evaporation-induced self-assembly of a mixture of sisal cellulose nanofibers (CNF) and polyethylene glycol (PEG) as the matrix and citric acid (CA) as a cross-linking agent. The CNF/PEG/CA paper exhibited good water swelling resistance which could be controlled by changing the concentration of CA. In addition, this nanocomposite paper exhibited good mechanical properties and water-induced shape memory performance. In particular, when the dosage of CA was 30 wt.%, the tensile strength and the tensile modulus of the CNF/PEG/CA paper after swelling were 25.2 MPa and 813.0 MPa, respectively. Further, this nanocomposite showed great potential for water-induced shape memory materials with fast response speed. The shape recovery rate (Rr) of the CNF/PEG/CA paper reached 90.2% with 30 wt.% CA after being immersed in water for 11 s. It is anticipated that our current work can be used to exploit more efficient methods to overcome the poor water swelling resistance of the cellulose-based shape memory materials.

Cellulose nanofibers/polyurethane shape memory composites with fast water-responsivity

2018 ◽  
Vol 6 (11) ◽  
pp. 1668-1677 ◽  
Author(s):  
Yongzhen Wang ◽  
Zhongjun Cheng ◽  
Zhenguo Liu ◽  
Hongjun Kang ◽  
Yuyan Liu
Keyword(s):  
Shape Memory ◽  
Memory Performance ◽  
Cellulose Nanofibers ◽  
Memory Ability ◽  
Shape Memory Composites

The PU/CNF nanocomposites display water-triggered fast shape memory ability, such as curling and unfolding, demonstrating tailored shape memory performance.

The Two-Stage Curing Method for Shape-Memory Materials

2012 ◽  
Vol 476-478 ◽  
pp. 2227-2230
Author(s):  
He Sun ◽  
Yu Yan Liu ◽  
Hui Feng Tan ◽  
Chang Guo Wang
Keyword(s):  
Shape Memory ◽  
Memory Performance ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Two Stage ◽  
Memory Tests ◽  
Second Stage ◽  
Shape Memory Properties ◽  
Shape Memory Materials ◽  
Curing Method

In this paper, a various shape-memory materials had been prepared by two-stage curing method. The purpose of using this approach was to maintain the excellent shape memory properties and low glass transition temperature (Tg) of shape-memory materials after first stage curing, furthermore, improve the Tg and heat resistence effectively after second stage curing. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and fold-deploy shape memory tests were used to characterize the feasibility of two-stage curing, thermodynamics properties and shape memory performance of these polymers. DSC results showed that two different curing stages could be achieved successfully, DMA results suggested that heat resistance of materials had been improved after second curing stage, while the fold-deploy shape memory tests proved that the composites possessed excellent shape memory properties, it could be deformed into different shape and recovered its original shape fully within three minutes.

Characterization of polymeric shape memory materials

2017 ◽  
Vol 37 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Xue Lian Wu ◽  
Wei Min Huang ◽  
Hai Bao Lu ◽  
Chang Chun Wang ◽  
Hai Po Cui
Keyword(s):  
Shape Memory ◽  
Memory Effect ◽  
Memory Performance ◽  
Shape Memory Polymer ◽  
Testing Methods ◽  
Temperature Memory Effect ◽  
Shape Memory Materials ◽  
Standard Techniques ◽  
Selection Of

Abstract After a short discussion of various shape memory related phenomena and the basic working mechanisms behind the shape memory effect (SME) in polymeric shape memory materials (SMMs), standard techniques and procedures to characterize these types of materials are reviewed in details (including the concerns in the selection of testing methods and parameters). Although the focus of this paper is on the heating-responsive SME, important issues in the chemo-responsive SME are addressed. Furthermore, some other shape memory related phenomena, such as various kinds of temperature memory effect (TME), and multiple-SME etc., and optimization of the shape memory performance of a shape memory polymer (SMP) via tailoring the programming parameters are included.

scholarly journals Recent Developments in Small-Scale Shape Memory Oxides

2020 ◽  
Vol 6 (3) ◽  
pp. 287-300
Author(s):  
Xiao Wang ◽  
Alfred Ludwig
Keyword(s):  
Shape Memory ◽  
Memory Performance ◽  
High Strength ◽  
Transformation Strain ◽  
Strain Engineering ◽  
Small Scale ◽  
Micro Cracks ◽  
Recent Developments ◽  
Shape Memory Effects ◽  
Shape Memory Materials

Abstract This review presents an overview of the developments in small-scale shape memory materials: from alloys to oxides and ceramics. Shape memory oxides such as zirconia, different ferroelectric perovskites and VO2-based materials have favorable characteristics of high strength, high operating temperature and chemical resistance, which make this class of shape memory materials interesting for special applications, e.g., in harsh environments or at the nanoscale. Because of the constraint and mismatch stress from neighboring grains in polycrystalline/bulk oxides, the transformation strain of shape memory oxides is relatively small, and micro-cracks can appear after some cycles. However, recent progress in shape memory oxide research related to small-scale approaches such as decreasing the amounts of grain boundaries, strain-engineering, and application in the form of nanoscale thin films shows that some oxides are capable to exhibit excellent shape memory effects and superelasticity at nano/micro-scales. The materials systems ZrO2, BiFO3, and VO2 are discussed with respect to their shape memory performance in bulk and small-scale.

scholarly journals Catalyst-Free Crosslinking Modification of Nata-De-Coco-Based Bacterial Cellulose Nanofibers Using Citric Acid

2021 ◽  
Author(s):  
Rabiu Salihu ◽  
Saiful Izwan Abd Razak ◽  
Nurliyana Ahmad Zawawi ◽  
Shafinaz Shahir ◽  
Mohd Helmi Sani ◽  
...  
Keyword(s):  
Citric Acid ◽  
Bacterial Cellulose ◽  
Materials Science ◽  
Cellulose Nanofibers ◽  
Tensile Modulus ◽  
Wound Dressings ◽  
Crosslinking Reaction ◽  
Research Attention ◽  
Catalyst Free ◽  
Tissue Scaffolding

Abstract Bacterial cellulose (BC) has gained research attention in materials science and biomedicine due to its fascinating properties. BCs' fiber collapse phenomenon (inability to reabsorb water after dehydration) is one of the drawbacks that limit its potentials. To overcome this, a catalyst-free thermal crosslinking reaction was employed to modify the BC using citric acid (CA) without compromising the biocompatibility. Properties evaluation of the modified BC (MBC) by FTIR, XRD, SEM/EDX, TGA, and Tensile analysis confirmed the fiber crosslinking and improvement of some properties that could be advantageous for various applications. The modified nanofiber seems to maintain its inherent crystallinity and thermal stability with an increased water absorption/swelling and tensile modulus. The resulting MBC reported here can be relevant for wound dressings and tissue scaffolding.

Effect of Carbon Nanotubes on the Shape Memory Performance of Poly(vinylidene fluoride)/Acrylic Blends

2013 ◽  
Vol 30 (2) ◽  
pp. 134
Author(s):  
Hui FU ◽  
Jishan QIU ◽  
Ning CHONG ◽  
Yaqing WANG ◽  
Yuanyuan TIAN ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Shape Memory ◽  
Vinylidene Fluoride ◽  
Memory Performance ◽  
Poly Vinylidene Fluoride

Effect of Polyethylene Glycol in Nanocellulose/PLA Composites

2019 ◽  
Vol 821 ◽  
pp. 89-95
Author(s):  
Wanasorn Somphol ◽  
Thipjak Na Lampang ◽  
Paweena Prapainainar ◽  
Pongdhorn Sae-Oui ◽  
Surapich Loykulnant ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Polyethylene Glycol ◽  
Aspect Ratio ◽  
Mechanical Performance ◽  
Tensile Modulus ◽  
Poly Lactic Acid ◽  
Solvent Casting ◽  
Casting Method ◽  
Mediated Oxidation

Poly (lactic acid) or PLA was reinforced by nanocellulose and polyethylene glycol (PEG), which were introduced into PLA matrix from 0 to 3 wt.% to enhance compatibility and strength of the PLA. The nanocellulose was prepared by TEMPO-mediated oxidation from microcrystalline cellulose (MCC) powder and characterized by TEM, AFM, and XRD to reveal rod-like shaped nanocellulose with nanosized dimensions, high aspect ratio and high crystallinity. Films of nanocellulose/PEG/PLA nanocomposites were prepared by solvent casting method to evaluate the mechanical performance. It was found that the addition of PEG in nanocellulose-containing PLA films resulted in an increase in tensile modulus with only 1 wt% of PEG, where higher PEG concentrations negatively impacted the tensile strength. Furthermore, the tensile strength and modulus of nanocellulose/PEG/PLA nanocomposites were higher than the PLA/PEG composites due to the existence of nanocellulose chains. Visual traces of crazing were detailed to describe the deformation mechanism.

scholarly journals In Situ Generation of Green Hybrid Nanofibrillar Polymer-Polymer Composites—A Novel Approach to the Triple Shape Memory Polymer Formation

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1900
Author(s):  
Ramin Hosseinnezhad ◽  
Iurii Vozniak ◽  
Fahmi Zaïri
Keyword(s):  
Polymer Blends ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Cellulose Nanofibers ◽  
Polymeric Materials ◽  
Novel Approach ◽  
Phase Transition Temperatures ◽  
Triple Shape Memory

The paper discusses the possibility of using in situ generated hybrid polymer-polymer nanocomposites as polymeric materials with triple shape memory, which, unlike conventional polymer blends with triple shape memory, are characterized by fully separated phase transition temperatures and strongest bonding between the polymer blends phase interfaces which are critical to the shape fixing and recovery. This was demonstrated using the three-component system polylactide/polybutylene adipateterephthalate/cellulose nanofibers (PLA/PBAT/CNFs). The role of in situ generated PBAT nanofibers and CNFs in the formation of efficient physical crosslinks at PLA-PBAT, PLA-CNF and PBAT-CNF interfaces and the effect of CNFs on the PBAT fibrillation and crystallization processes were elucidated. The in situ generated composites showed drastically higher values of strain recovery ratios, strain fixity ratios, faster recovery rate and better mechanical properties compared to the blend.

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