scholarly journals Recording, Storage, and Reproduction of Information on Polyvinyl Chloride Films Using Shape Memory Effects

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1802
Author(s):  
Alexander P. Kondratov ◽  
Egor P. Cherkasov ◽  
Vladislav Paley ◽  
Alex A. Volinsky

Partial dissolution and plasticization are used for recording, storing, and reproducing information with modified industrial screen-printing equipment and aqueous solutions of colorless organic liquids on small surface area shape memory polymer films. To justify the choice of “ink” and evaluate the effectiveness of using organic liquids as high-speed polymer solvents, the new method for recording hidden information uses the calculation of the solubility parameter, differential scanning calorimetry, and the method of one-sided swelling of films under isometric conditions. Using the example of tactile marking of shrink labels made of polyvinyl chloride, the optimal conditions for recording hidden information on a film are established in terms of the concentration of an aqueous solution of tetrahydrofuran, the contact time, and the processing temperature of the polymer using screen printing equipment.

2020 ◽  
Vol 1010 ◽  
pp. 142-147
Author(s):  
Nur Athirah Rasli @ Rosli ◽  
Syazana Ahmad Zubir

Various polyurethane-based shape memory polymer was synthesized using polycaprolactone (PCL) as soft segment and, hexamethylene diisocyanate (HMDI) and isophorone diisocyanate (IPDI) as the hard segments. Palm kernel oil-based polyol was used to replace part of the petroleum-based polyol due to the increasing demand on renewable resources as a result of environmental awareness. The synthesis has been carried out using two step polymerization method. The effects of varying the molar ratio of IPDI/HMDI on material properties such as crystallinity, transition temperature, morphology, shape memory effect and tensile strength were investigated by using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), shape memory test and tensile test. A high IPDI content in SMPU results in better shape memory effect, whereas increasing HMDI content leads to a better chain flexibility. In this work, the incorporation of IPDI contributes to the formation of phase separation which enhance the formation of crystalline soft segment structure while the incorporation of HMDI as isocyanate tend to promote phase mixing which enhance the chain flexibility of the SMPU backbone.


Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3767
Author(s):  
Dalia Niazy ◽  
Ahmed Elsabbagh ◽  
Mostafa R. Ismail

Dynamic shading systems in buildings help reduce solar gain. Actuated systems, which depend on renewable energy with reduced mechanical parts, further reduce building energy consumption compared to traditional interactive systems. This paper investigates stimuli-responsive polymer application in architectural products for sustainable energy consumption, complying with sustainable development goals (SDGs). The proposed research method posits that, by varying the infill percentage in a pre-determined manner inside a 3D-printed mono-material component, directionally controlled shape change can be detected due to thermal stimuli application. Thus, motion behavior can be engineered into a material. In this study, PLA+, PETG, TPU and PA 6 printed components are investigated under a thermal cycle test to identify a thermally responsive shape-memory polymer candidate that actuates within the built environment temperature range. A differential scanning calorimetry (DSC) test is carried out on TPU 95A and PA 6 to interpret the material shape response in terms of transitional temperatures. All materials tested show an anisotropic shape-change reaction in a pre-programmed manner, complying with the behavior engineered into the matter. Four-dimensional (4D)-printed PA6 shows shape-shifting behavior and total recovery to initial position within the built environment temperature range.


Author(s):  
Veysel Erel ◽  
Jessica L. Berry ◽  
Arun Srinivasa ◽  
Terry S. Creasy

Designing devices made from epoxy-based shape memory polymers is difficult because few material behavior parameters are available for these materials in the rubbery/shape changing region. This work examines the rubbery state, greater than 20° C above the glass transition temperature (Tg), as an elastomeric regime suited to characterization with simple tension and planar tension experiments. Differential scanning calorimetry (DSC) results show a 70° C Tg, which agrees with prior research. Simple tension experiments at 100° C exhibited nonlinear elastic behavior, and finite element analysis (FEA) agreed with the constitutive behavior exhibited in the experiments. Planar tension experiments exhibited novel results. The stress/strain response was sigmoidal with a significant plateau in stress followed by rising stress to failure. The typical 10:1 gage width/gage length ratio seemed to over constrain the material. The strain to failure is small, and suggests the material behavior is a hybrid of elastic and hyperelastic behavior.


Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1629
Author(s):  
Gheorghe Gurau ◽  
Carmela Gurau ◽  
Francisco Manuel Braz Fernandes ◽  
Petrica Alexandru ◽  
Vedamanickam Sampath ◽  
...  

It is generally accepted that severe plastic deformation (SPD) has the ability to produce ultrafinegrained (UFG) and nanocrystalline materials in bulk. Recent developments in high pressure torsion (HPT) processes have led to the production of bimetallic composites using copper, aluminum or magnesium alloys. This article outlines a new approach to fabricate multilayered Ni-Ti nanocomposites by a patented SPD technique, namely, high speed high pressure torsion (HSHPT). The multilayered composite discs consist of Ni-Ti alloys of different composition: a shape memory alloy (SMA) Ti-rich, whose Mf > RT, and an SMA Ni-rich, whose Af < RT. The composites were designed to have 2 to 32 layers of both alloys. The layers were arranged in different sequences to improve the shape recovery on both heating and cooling of nickel-titanium alloys. The manufacturing process of Ni-Ti multilayers is explained in this work. The evolution of the microstructure was traced using optical, scanning electron and transmission electron microscopes. The effectiveness of the bonding of the multilayered composites was investigated. The shape memory characteristics and the martensitic transition of the nickel-titanium nanocomposites were studied by differential scanning calorimetry (DSC). This method opens up new possibilities for designing various layered metal-matrix composites achieving the best combination of shape memory, deformability and tensile strength.


Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1107
Author(s):  
Mijeong Kim ◽  
Seongeun Jang ◽  
Sungwoong Choi ◽  
Junghoon Yang ◽  
Jungpil Kim ◽  
...  

Shape memory polymers (SMPs) are attracting attention for their use in wearable displays and biomedical materials due to their good biocompatibility and excellent moldability. SMPs also have the advantage of being lightweight with excellent shape recovery due to their low density. However, they have not yet been applied to a wide range of engineering fields because of their inferior physical properties as compared to those of shape memory alloys (SMAs). In this study, we attempt to find optimized shape memory polymer composites. We also investigate the shape memory performance and physical properties according to the filler type and amount of hardener. The shape memory composite was manufactured by adding nanocarbon materials of graphite and non-carbon additives of Cu. The shape-recovery mechanism was compared, according to the type and content of the filler. The shape fixation and recovery properties were analyzed, and the physical properties of the shape recovery composite were obtained through mechanical strength, thermal conductivity and differential scanning calorimetry analysis.


2015 ◽  
Vol 1718 ◽  
pp. 123-130 ◽  
Author(s):  
Matthias Heuchel ◽  
Laith Al-Qaisi ◽  
Karl Kratz ◽  
Ulrich Nöchel ◽  
Marc Behl ◽  
...  

ABSTRACTCrosslinked poly[ethylene-co-(vinyl acetate)] (cPEVA) has been recently introduced as a polymer material, which can be functionalized with various shape-memory effects by solely altering the thermomechanical treatment called programming.In this study two series of cPEVAs with different vinyl acetate contents of 18 wt% (cPEVA18) and 28 wt% (cPEVA28) comprising different crosslink densities were investigated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) in the temperature range of -130 °C to 120 °C. DMTA tests were performed in torsion mode, because such movements are highly relevant in the context of complex shape changes in shape-memory polymer based devices. Finally, the obtained DMTA results were compared with DMTA conducted in tension mode. Swelling experiments revealed a gel content in the range from 81% to 90% for cPEVA18 samples while for cPEVA28s a complete conversion was observed. The degree of swelling was found to decrease substantially with increasing crosslink density for both cPEVA series.The influence of VA content and extent of crosslinking on the appearance of the respective melting (Tm) and glass transition (Tg) as well as the thermomechanical properties of cPEVA systems could be demonstrated by discussing both DSC and DMTA results. The temperature range of mechanical stability correlates with the VA content and is determined by decreasing Tm values. The cross links do barely alter the stiffness of a PEVA up to the Tm rang, but lead to constant mechanical rigidity in the rubbery range above Tm.


2020 ◽  
Vol 54 (28) ◽  
pp. 4441-4455
Author(s):  
JE Rodriguez ◽  
DH Giraldo ◽  
JC Restrepo ◽  
HA Colorado

Semicrystalline polymeric systems are a type of Shape Memory Polymer (SMP), which are more straightforward to synthesize in comparison with other class of stimulus-responsive polymers. On these systems, the shape memory is triggered by temperature and partially driven by crystallization-induced elongation, heating-induced contraction, and elastic entropy. However, a stable temporary and permanent shape through cycling is not easy to achieve. For that reason, a laminar composite made based in the encapsulation of ethylene vinyl acetate (EVA) inside a PU matrix was developed, with the aim of obtaining an actuator with a preferred deformation direction and stable change of shape. In this study, chemically cross-linked ethylene vinyl acetate copolymer (cEVA) as SMP was synthesized and functionalized as a reinforcing strip. A temperature-memory actuator composite was manufactured by the encapsulation of a shape memory programmed strip in an elastomer matrix. The shape memory properties and thermocycling assessment were evaluated using differential scanning calorimetry and dynamic mechanical analysis. Results show the ability of the actuator to bend and unbend, following multiple consecutive heating-cooling cycles. The relationship between the strip, the matrix, and the interface is critical in the bending and shape memory maintenance.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2177
Author(s):  
Lu Lu Taung Mai ◽  
Min Min Aung ◽  
Sarah Anis Muhamad Saidi ◽  
Paik San H’ng ◽  
Marwah Rayung ◽  
...  

The use of bio-based polymers in place of conventional polymers gives positives effects in the sense of reduction of environmental impacts and the offsetting of petroleum consumption. As such, in this study, jatropha oil was used to prepare epoxidized jatropha oil (EJO) by the epoxidation method. The EJO was used to prepare a shape memory polymer (SMP) by mixing it with the curing agent 4-methylhexahydrophthalic anhydride (MHPA) and a tetraethylammonium bromide (TEAB) catalyst. The resulting bio-based polymer is slightly transparent and brown in color. It has soft and flexible properties resulting from the aliphatic chain in jatropha oil. The functionality of SMP was analyzed by Fourier transform infrared (FTIR) spectroscopy analysis. The thermal behavior of the SMP was measured by thermogravimetric analysis (TGA), and it showed that the samples were thermally stable up to 150 °C. Moreover, the glass transition temperature characteristic was obtained using differential scanning calorimetry (DSC) analysis. The shape memory recovery behavior was investigated. Overall, EJO/MHPA was prepared by a relatively simple method and showed good shape recovery properties.


2014 ◽  
Vol 787 ◽  
pp. 275-280
Author(s):  
Li Min Zhao ◽  
Xue Feng ◽  
Xu Jun Mi ◽  
Yan Feng Li ◽  
Hao Feng Xie ◽  
...  

A critical parameter for a shape memory polymer (SMP) lies in its shape memory transition temperature. For an amorphous SMP polymer, it is highly desirable to develop methods to tailor its Tg, which corresponds to its shape memory transition temperature. Starting with an amine cured aromatic epoxy system, epoxy polymers were synthesized by introducing flexible aliphatic alcohol. The thermal and thermomechanical properties of these epoxy polymers were characterized by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). All the crosslinked epoxy polymers with Tg’s above room temperature were found to possess shape memory properties.


Author(s):  
G. P. Tandon ◽  
T. Gibson ◽  
J. Shumaker ◽  
R. Coomer ◽  
J. Baur ◽  
...  

In the present study, a series of novel linear polyaspartimide-based silane endcapped (cross-linked) polymers are synthesized using 4-4′ bismaleimidodiphenylmethane, Jeffamine D-400 (BMI-JA-400), and (3-Aminopropyl) trimethoxysilane. To add strength to these systems, the trimethoxysilane moiety is cross-linked with the addition of water to create a thermosetting material with both improved toughness and variable cross-link densities. Thermal analysis is done to evaluate the developed shape-memory polymer (SMP) resin for composite processing feasibility. The solvent content in the resin and thermal stability is monitored using thermogravimetric analysis (TGA) while advanced rheometric expansion system (ARES) with parallel plate geometry is used to measure viscosity variation with temperature. The resin BMI-JA-400-Si-70/30 is chosen for making the composite based on its viscosity, weight change, and kinetic results. Differential scanning calorimetry (DSC) is performed to determine the cure kinetics including the temperatures at which the cure reaction initiates and completes in order to develop the cure cycle for composite fabrication. The selected SMP resin is hand-impregnated with T-300 plain-weave and T-700 uni-weave carbon fabric. Six-ply composites are successfully fabricated with < 2% void content using both fabric weaves. The thermo-mechanical properties of the SMP resin are measured using dynamic mechanical analysis (DMA). In addition, the shape memory cycle with free recovery is conducted on the SMP resin and composites.


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