Effect of chemical cross‐linking under elongation on shape restoring of poly(vinyl alcohol) hydrogel

Hirai, Toshihiro; Maruyama, Hidetoshi; Suzuki, Takashi; Hayashi, Sadao

doi:10.1002/app.1992.070460815

Cited by 55 publications

(26 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…10 -12 Hirai et al have studied the influence of chemical crosslinked structures on the shape-memory behavior of poly(vinyl alcohol) hydrogel. 13,14 Li has introduced the structure of interpenetrating polymer networks (IPNs) to shape-memorized polyacrylamide. 15 In our previous study, the influences of hard segment content 16 and soft segment molecular weight (MW) 17 on the shape-memory behavior of polyether-based PUs were studied.…”

Section: Introductionmentioning

confidence: 99%

Shape-memorized crosslinked ester-type polyurethane and its mechanical viscoelastic model

Lin

Chen

1999

J. Appl. Polym. Sci.

129

View full text Add to dashboard Cite

A series of shape-memorized crosslinked ester-type polyurethanes (PUs), based on different compositions of 4,4Ј-diphenyl methane diisocyanate (MDI), poly(butylene adipate) glycol (PBAG) with different molecular weight (MW) and trimethylol propane (TMP), were synthesized. The morphology of samples was investigated by using DSC, WAXD, and dynamic mechanical analysis (DMA). It was found that the morphology of the soft segment, which was PBAG with a different MW, was in an amorphous state and no crystalline domain was found. By increasing the crosslinked density (varying the content of TMP) or decreasing the length of the soft segment (MW of PBAG), the glass transition temperature of studied samples increased. But the range of transition broadened and the modulus ratio EЈ (T g Ϫ20°C) /EЈ (T g ϩ20°C) also decreased. The shape-memory behavior was studied by the bending test method adopted from the shape-memory alloy. The sample with high T g showed not only a high recovered temperature (T r ) but also a high recovered rate (V r ) with a high modulus ratio. By introducing the chemical crosslinked structure, the deformed samples completely recovered their original shape and rendered shape-memory behavior under the complex deformation. The shape-memorized crosslinked ester-type PUs can be applied at different operating temperatures. A mechanical viscoelastic model is discussed for the shape-memory behavior of PUs, and the modified Bonart's viscoelastic model properly describes the mechanism of the shape memory of PUs.

show abstract

Section: Introductionmentioning

confidence: 99%

Shape-memorized crosslinked ester-type polyurethane and its mechanical viscoelastic model

Lin

Chen

1999

J. Appl. Polym. Sci.

129

View full text Add to dashboard Cite

show abstract

“…8.6. This localization of the chemical crosslinks gives the gel not only a toughness but a shape memory [19][20][21]. The hydrogel was shrunk in methanol or acetone to remove the water from the gel.…”

Section: Preparation Methods Of the Dmso Gelmentioning

confidence: 99%

Electrically Induced Strain in Polymer Gels Swollen with Non-Ionic Organic Solvents

Hirai¹,

Hirai²

2000

Polymer Sensors and Actuators

Self Cite

View full text Add to dashboard Cite

IntroductionPolymer gel actuator has been extensively studied from the standpoints of new intelligent materials. When we define the intelligent material as one that has three functions in a body -sensing, processing, and response or action -polymer gels are adequate as intelligent materials, since they respond by taking various stimuli in the surroundings into account. Polymer gel actuator can be considered, in this sense, as one of the intelligent materials or artificial muscle, which can actuate by sensing various triggers or stimuli to generate strain, taking various factors into account. There has been vast variations of reports on swelling-and-deswelling features induced by changing ionic strength, pH value, solvent composition, and temperature [1][2][3][4][5]. In polyelectrolyte gels, a strain can also be induced by an electric field [6][7][8][9][10]. The electrically induced strain has been considered to be caused principally by electrostatic repulsion or attraction among the ionic species in the gels. The other type of approach is a magnetostrictive action of a ferrofluid immobilizing hydrogel, in which the superparamagnetic properties of the ferrofluid has been utilized and the dispersion mode of the ferro magnetic particles has a serious effect on the strain generation [11][12][13][14][15].Here we will introduce our results on the electrostrictive polymer gels which are swollen with non-ionic organic solvents and which can be actuated by applying an electric field. The gels showed very quick motion compared to the conventional polyelectrolyte gels with application of a direct current electric field. We will show the feature of the action and the structure change of the gel induced by the electric field, discuss the mechanism of the electrostrictive motion of the gels, and make some suggestions to the future development of this type of material. Electrically Induced Strain in PVA-DMSO Gel [16] Electrostrictive Motion of PVA-DMSO GelPoly(vinyl alcohol) gel swollen with dimethylsulfoxide (DMSO) can be actuated by applying an electric field as shown in Fig. 8

show abstract

“…Due to the synergistic effects of fibers and paper, heat transfer was facilitated and the electrical resistivity of the SMP composite was 10 16 times lower than for pure SMP resin. Nevertheless, the shortest detected shape recoveries took quite long (186 s) and shape recoverabilities were reduced with increasing carbon nanofiber contents, which was explained by the accumulation of interfacial friction effects between the SMP's macromolecular segments, carbon nanopaper and the blended carbon nanofiber particles.…”

Section: Electrically Conductive Smp Compositesmentioning

confidence: 99%

“…To date, much attention has been directed to a variety of functional materials including alloys [1][2][3], ceramics [4][5][6], polymers [7][8][9][10][11][12][13][14] and gels [15][16][17][18][19], which have all been found to exhibit shape memory behavior. Particularly, shape memory polymer (SMP) research is a continuously growing working…”

Section: Introductionmentioning

confidence: 99%

Review on the Functional Determinants and Durability of Shape Memory Polymers

Pretsch

2010

Polymers

113

View full text Add to dashboard Cite

Shape memory polymers (SMP) belong to the class of stimuli-responsive materials and have generated significant research interest. Their capability to retain an imposed, temporary shape and to recover the initial, permanent shape upon exposure to an external stimulus depends on the "functional determinants", which in simplistic terms, can be divided into structural/morphological and processing/environmental factors. The primary aim of the first part of this review is to reflect the knowledge about these fundamental relationships. In a next step, recent advances in shape memory polymer composites are summarized. In contrast to earlier reviews, studies on the impairment of shape memory properties through various factors, such as aging, compression and hibernation, lubricants, UV light and thermo-mechanical cycling, are extensively reviewed. Apart from summarizing the state-of-the-art in SMP research, recent progress is commented.

show abstract

Effect of chemical cross‐linking under elongation on shape restoring of poly(vinyl alcohol) hydrogel

Cited by 55 publications

References 7 publications

Shape-memorized crosslinked ester-type polyurethane and its mechanical viscoelastic model

Shape-memorized crosslinked ester-type polyurethane and its mechanical viscoelastic model

Electrically Induced Strain in Polymer Gels Swollen with Non-Ionic Organic Solvents

Review on the Functional Determinants and Durability of Shape Memory Polymers

Contact Info

Product

Resources

About