Glass Transition Behavior of Wet Polymers

Li, Hai

doi:10.3390/ma14040730

Cited by 9 publications

(7 citation statements)

References 32 publications

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“…The CGG + PolyOX thermogram did not show a Tg. Thus, it can be inferred that the addition of PolyOX in the absence of the crosslinker generates an HG with higher crystallinity, considering that the Tg is usually a characteristic presented by amorphous or semi-crystalline materials [ 19 ]. On the other hand, for peak 3, the Tm decreases for CL CGG, increases in CGG + PolyOX, and decreases again in CGG-PolyOX but above CL CGG; this same behavior was presented for Td in peak 4.…”

Section: Resultsmentioning

confidence: 99%

Novel ultra-stretchable and self-healing crosslinked poly (ethylene oxide)-cationic guar gum hydrogel

Bernal-Chávez,

Alcalá-Alcalá,

Almarhoon

et al. 2023

J Biol Eng

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Hydrogels are three-dimensional structures with specific features that render them useful for biomedical applications, such as tissue engineering scaffolds, drug delivery systems, and wound dressings. In recent years, there has been a significant increase in the search for improved mechanical properties of hydrogels derived from natural products to extend their applications in various fields, and there are different methods to obtain strengthened hydrogels. Cationic guar gum has physicochemical properties that allow it to interact with other polymers and generate hydrogels. This study aimed to develop an ultra-stretchable and self-healing hydrogel, evaluating the influence of adding PolyOX [poly(ethylene oxide)] on the mechanical properties and the interaction with cationic guar gum for potential tissue engineering applications. We found that variations in PolyOX concentrations and pH changes influenced the mechanical properties of cationic guar gum hydrogels. After optimization experiments, we obtained a novel hydrogel, which was semi-crystalline, highly stretchable, and with an extensibility area of approximately 400 cm2, representing a 33-fold increase compared to the hydrogel before being extended. Moreover, the hydrogel presented a recovery of 96.8% after the self-healing process and a viscosity of 153,347 ± 4,662 cP. Therefore, this novel hydrogel exhibited optimal mechanical and chemical properties and could be suitable for a broad range of applications in different fields, such as tissue engineering, drug delivery, or food storage.

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Section: Resultsmentioning

confidence: 99%

Novel ultra-stretchable and self-healing crosslinked poly (ethylene oxide)-cationic guar gum hydrogel

Bernal-Chávez,

Alcalá-Alcalá,

Almarhoon

et al. 2023

J Biol Eng

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“…The amount of diffused second polymer chains in the PMMA cores is calculated on the basis of the difference between the peak area of the PMMA core and the peak area of the deconvoluted peak associated with the PMMA for composite particles in the derivate graphs of C p in Figure f–j (see the Supporting Information). The percentage of diffused polymers versus the difference between T g of the water-saturated polymer ( T gw ) , and T r (Δ T = T gw – T r ) is presented in Figure . It can be clearly seen that the percentage of diffused polymers decreases as the Δ T increases, and the maximum polymer chain diffusion happens for the sample with PnBA as the second polymer, which is about 40%; so, all samples have the CS structure.…”

Section: Resultsmentioning

confidence: 99%

Surface Morphology Signature of Critical Separated Length and Glass Transition Temperature during Seeded Dispersion Polymerization

Kiany

Goharpey

2021

Langmuir

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The properties of colloids are considerably affected by particles’ surface morphology. In this work, for understanding the mechanism of roughness formation in polymeric core–shell (CS) particles, the surface morphology of synthesized CS particles through seeded dispersion polymerization (SDP) in the presence of poly(methyl methacrylate) seeds was investigated. The results revealed that shell polymers with higher solubility parameters (δ) and glass transition temperatures (T g) had a rougher surface. These parameters directly affect the time needed for chain deformation, which is a critical parameter in controlling the final morphology. We suggested a relation based on these parameters to predict the surface morphology (smoothness or roughness) of CS particles synthesized through SDP in water.

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“…For the cases of Figure 5d, laminates have two glassy states before reached to a rubbery state. The first T g was occurred due to prolonged moisture absorption which acts as a plasticizer that was a case on reducing hydrogen bond, Van der Waals forces and hardness of the laminates [27,28]. In those figures, the response on E of all laminates was similar at 1 Hz and 10 Hz.…”

Section: Dma Testsmentioning

confidence: 88%

Mechanical Behavior of GFRP Laminates Exposed to Thermal and Moist Environmental Conditions: Experimental and Model Assessment

2022

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This paper presents an experimental and analytical study about the mechanical response at a different temperature on glass fiber-reinforced polymer laminates. The effect of different environmental conditions on compressive, tensile, stiffness, and viscoelastic behavior (storage modulus, loss modulus and damping ratio) of laminates were investigated. Before testing, laminates were preserved in a deep freezer at −80 °C, −20 °C, 0 °C, and room temperature (25 °C) for up to 60 days. Results confirmed that temperatures ranging from −80 to 50 °C, which were below the glass transition temperature of the epoxy resin, did not significantly affect the compressive, tensile, and stiffness performance of all laminates. When the testing temperature increased to 100 °C, the properties were decreased significantly due to the damaging of the fiber/matrix interface. Additionally, results obtained from dynamic mechanical analyses tests showed a drop-in storage modulus, high peaks in loss modulus and high damping factor at the glass transition region of the epoxy resin. The highest storage modulus, two phases of glassy states and highest damping ratio on the −80/G group of laminates were obtained. The accuracy of experimental results was assessed with empirical models on the storage modulus behavior of laminates. The empirical model developed by Gibson et al. provided accurate estimates of the storage modulus as a function of temperature and frequency. The remaining empirical models were less accurate and non-conservative estimations of laminates stiffness.

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Glass Transition Behavior of Wet Polymers

Cited by 9 publications

References 32 publications

Novel ultra-stretchable and self-healing crosslinked poly (ethylene oxide)-cationic guar gum hydrogel

Novel ultra-stretchable and self-healing crosslinked poly (ethylene oxide)-cationic guar gum hydrogel

Surface Morphology Signature of Critical Separated Length and Glass Transition Temperature during Seeded Dispersion Polymerization

Mechanical Behavior of GFRP Laminates Exposed to Thermal and Moist Environmental Conditions: Experimental and Model Assessment

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