The optimal PVA/PA/PANi hydrogel displays dark green color with a uniform distribution of PA/PANi particles. After experiencing repetitive 4 × 100 stretching at a strain of 10%, the hydrogel exhibits an enhanced fracture strength (20.35 MPa), Young''s modulus (22.66 MPa), and toughness (36.24 MJ·m –3 ) compared with the original …
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Storage modulus (G′) and loss modulus (G″) vs. frequency (ω) for PVA solution systems at 90 C at several concentrations: in DMSO/water and (b) in NMMO monohydrate. Download : Download full-size image Fig. 6.
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Poly (vinyl alcohol) (PVA) is a water-soluble, transparent, semi-crystalline polymer with excellent mechanical properties, chemical resistance, and biocompatibility. The crystallinity, optical and mechanical properties of PVA can be modified by the crosslinking process. In this work, a simple heat treatment method is used to fulfil this …
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The storage modulus of PVA/starch/GO nanocomposite at 30 C was significantly dropped from 6.3 to 4.5 MPa (approximately 27.5%, decreasing) after irradiation for 10 min. Then, with increasing irradiation time to 20 min, 30 min, and 40 min, the storage modulus was increased to 5.9 MPa, 9.4 MPa, and 8.2 MPa, respectively.
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The storage modulus of PVA and the blends up to 70 wt% of PVA decreases with the increase in temperature within whole experimental range. However, in case of blends with higher amounts of PAA, after the initial drop in storage modulus, there was an increase in storage modulus at higher temperature above the T g of PAA (130 °C).
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Increase of strength and modulus of films were dependent on the storage conditions. •. PFQNM successfully explains the influence of moisture on the properties of films. Cellulose nanofibers (CN) with high aspect ratio were obtained and their transverse modulus (Et) was determined for the first time by peak force (PF) QNM (quantitative ...
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Dynamic rheology of PVA/PAM hydrogels with 7.5 wt% PVA. Storage modulus (G′) and loss modulus (G″) of hydrogels on (a) frequency and (b) strain sweeps. …
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The storage modulus of the pure PVA (E = 1.36 × 10 9 Pa) was lower than the PVA/MMT composite polymer membranes with 5 and 10 wt.% MMT (E = 4.01-5.43 × 10 9 Pa) at 25 • C. It was clear that...
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The PVA utilized in this work is semi-crystalline, easily soluble in alcohol and water, non-toxic, has better dielectric strength and energy storage capacity values, and is easy to establish hydrogen bonds [22,23,24]. A single layer of carbon atoms with a 2D
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The resilience elasticity test demonstrated that the rebound percentage value of the n-STG-5 sample was 22.6% higher than the STG sample without PVA, due to its higher shear storage modulus. This study showed that PVA in the STG polymer matrix improves polymer chain cross-linking and performance due to its n-STG …
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The viscosity, storage modulus and elasticity were found to be higher for PVA solutions in DMSO than in water for the same concentration of PVA. However, the fiber diameter obtained from...
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The excellent mechanical properties of PVA, such as high modulus and high yield strength, result from intermolecular hydrogen bonds and are sufficient to qualify …
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An increase in the storage modulus is found in the temperature range of 20-70 C for the CS/PVA nano brous mat which is related to the evapo- ration of bound water. Fig. 6b shows the variations of ...
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storage modulus of PVA gel without particles. φ m stands for the maximum volume fraction of particles, which is n early equal to 0.63 for hard spheres [17]. The storage modulus only below the ...
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The data shows that PVA has a higher storage modulus in the direction it is stretched but there is a lot of deviation within the values for each test. Thus, it can be concluded that …
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addition of glutaraldehyde moves the G'' and G" crossover points to lower frequencies, while the addition of PVA decreases the storage and loss modulus values []. The different information that can be interpreted from frequency sweep rheograms is …
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The storage modulus was superior over the loss modulus for all the concentration of chitosan/PVA hydrogel referring that the hydrogels possess innate …
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The PVA/SG 50/50 hydrogel had the largest pore with 51.24% porosity and the highest cross-over point (28.17%) between the storage modulus (G′) and the loss modulus (G″).
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The data shows that PVA has a higher storage modulus in the direction it is stretched but there is a lot of deviation within the values for each test. Thus, it can be concluded that PVA is slightly anisotropic. Table 1: Storage Modulus Averages Test Average nd 4. ...
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The yield stress was defined as the point where the loss modulus (G″) exceeds the storage modulus (G′) of the storage/loss modulus curve. The recovery capability of inks was examined through an oscillatory time sweep test with 60 s intervals of high (100%) and low (1%) shear strains at 1 Hz frequency.
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Download scientific diagram | The (a) storage modulus (E ) and (b) tan δ of PVA nanofiber and SWNT/PVA composite nanofibers as a function of temperature in tensile mode (frequency = 1 Hz). from ...
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DMA analysis of PVA and PVA + CNF nanocomposites prepared at high and low temperature, pressure and time, (a and b) storage modulus and (c and d) tan δ peaks as a function of the temperature. Fig. 4 (c and d) show the effect of CNF content and molding process on the tan δ peak.
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Watase and Nishinariand Urushizaki et ~1.~ have demonstrated that the storage modulus in PVA hydrogels is increased with the number of freeze-thaw cycles and the concentration of PVA in the gel. Bo4 claimed to improve the mechanical properties of PVA hydrogels by cross-linking with epichlorohydrin and subsequent annealing.
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The storage modulus of the samples without PVA fiber (SCM-4) is lower than those of the PVA fiber-reinforced samples (SCM-5, SCM-6, and SCM-7) regardless of the temperature. The storage modulus of SCM-5, SCM-6, and SCM-7 aged at 28 days increase by 28.8, 58.9, and 151.9%, respectively, with the increase in the PVA fiber …
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Dynamic mechanical measurements of these blends and PAA as a function of temperature show an increase in storage modulus, E'', when they reach a temperature of 140 C that is well beyond their softening point. The E'' in EN ...
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The storage modulus of the pure PVA ( E ′ = 1.36 × 10 10 dyn cm − 2 ) was lower than the PVA/MMT nanocomposite polymer membranes with 5 and 10 wt.%MMT ( E ′ = 4.01 – 5.43 × 10 10 dyn cm − 2...
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Plots of loss and storage modulus for PVA solutions in DMSO (a, b) and water (c, d) Full size image Similarly, for the PVA-water system, the slope varied from 1.31 to 1.27 with increasing ...
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of PVA based films was done and storage modulus (E''), loss modulus (E'''') and tan δ had been determine as shown in figure 6. DMA curve clearly mark three regions in terms of different temperature ...
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PVA is a water-soluble polymer with 1, 3-diol units or 1, 2-diol units, which depends on the hydrolysis of poly (vinyl acetate). In addition, the content of 1, 2-diol units is reduced when the temperature of vinyl acetate polymerisation decreases. The chemical structures of PVA and viny alcohol are shown in Fig. 1.1.
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storage modulus of PAA is the only one showing the actual values. The storage modulus, E'', of PVA starts to decrease at 55 C with a smooth plateau up to 175 C. In contrast, the …
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The value of storage modulus (E´) of pure PVA (0%) at room temperature was 0.96 GPa, while the values of E ´ for composite contents 1, 5, 10 and 20 wt% PbTiO 3 are 0.87, 1.05, 1.3 and 2.14 GPa, respectively. The maximum increase was at 20 wt% PbTiO 3 ...
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