Changes in free volume and gas permeation properties of poly(vinyl alcohol) nanocomposite membranes modified using cage‐structured polyhedral oligomeric silsesquioxane

Swapna, Valiya Parambath; Kaliyathan, Abitha Vayyaprontavida; Abhisha, Vakkoottil Sivadasan; Maria, Hanna J.; Nambissan, P.M.G.; Thomas, Sabu; Stephen, Ranimol

doi:10.1002/app.49953

Cited by 8 publications

(5 citation statements)

References 51 publications

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“…The effect of the other additives may be explained on the basis of intermolecular interactions, where CS molecules diffuse between polymer chains and reduce the polymer chain–chain interaction in favor of chain–CS molecule interaction, which also increases the polymer void volume. This hypothesis has been proposed in a number of other reports on silsesquioxane-containing polymer materials [ 27 , 76 ]. Also, i Bu 7 SSQ-3OH showed a strong lubricating effect at 1% loading, which confirms that the amorphous products of its thermal condensation are more susceptible towards interaction with the polymer matrix.…”

Section: Resultsmentioning

confidence: 64%

Why POSS-Type Compounds Should Be Considered Nanomodifiers, Not Nanofillers—A Polypropylene Blends Case Study

et al. 2021

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In this work, a seriTables of silsesquioxanes (SSQ) and spherosilicates (SS), comprising a group of cage siloxane (CS) compounds, was tested as functional additives for preparation of isotactic polypropylene (iPP)-based nanocomposites and discussed in the aspect of their rationale of applicability as such additives. For this purpose, the compounds were prepared by condensation and olefin hydrosilylation reactions. The effect of these cage siloxane products on properties of obtained CS/iPP nanocomposites was analyzed by means of mechanical, microscopic (scanning electron microscopy-energy dispersive spectroscopy), thermal (differential scanning calorimetry, thermogravimetry), thermomechanical (Vicat softening point) analyses. The results were compared with the previous findings on CS/polyolefin composites. The role of CS compounds was discussed in terms of plastic processing additives.

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Section: Resultsmentioning

confidence: 64%

Why POSS-Type Compounds Should Be Considered Nanomodifiers, Not Nanofillers—A Polypropylene Blends Case Study

et al. 2021

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“…The weight loss in this region is nearly 4% and is not regarded as the degradation reaction of the polymer chain. Temperature at which a minimum of 10% of mass loss take place is considered to be the onset of degradation in macromolecules 31 . First stage principal thermal degradation of PVA takes place in the temperature range 215–350°C corresponding to the elimination reaction of acetate group residue persist in the PVA chain due to incomplete hydrolysis.…”

Section: Resultsmentioning

confidence: 99%

“…Temperature at which a minimum of 10% of mass loss take place is considered to be the onset of degradation in macromolecules. 31 First stage principal thermal degradation of PVA takes place in the temperature range 215-350 C corresponding to the elimination reaction of acetate group residue persist in the PVA chain due to incomplete hydrolysis. Second stage weight loss is observed in the temperature range 380-460 C, which mainly involves the degradation of carbonaceous materials such as polyene formed in first degradation step to yield carbon and hydrocarbon mixture.…”

Section: Pva/poss Systemsmentioning

confidence: 99%

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Efficient cage structured polyhedral oligomeric silsesquioxane embedded poly(vinyl alcohol) membranes: Thermal degradation and mechanical stability in hydrated condition

Swapna¹,

Krishnan²,

Abhisha³

et al. 2021

J of Applied Polymer Sci

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In this work, the thermal degradation of functionalized cage structured polyhedral oligomeric silsesquioxane (POSS) incorporated poly(vinyl alcohol) (PVA) and poly(vinyl alcohol)-poly (ethylene oxide) (PEO) blend membranes were discussed. PVA-PEO/POSS and cross-linked PVA/POSS systems exhibited excellent improvement in thermal stability at lower loading of POSS as compared to pure PVA and uncross-linked PVA/POSS system. Uncrosslinked PVA and PVA/POSS systems exhibited mainly two degradation steps. However, cross-linked PVA/POSS systems showed more degradation steps due to the formation of 3-dimentional network structure in the polymer. The mechanical stability of PVA/POSS and PVA-PEO/POSS systems at hydrated state were analyzed and observed a remarkable stability even in the wet condition.

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“…Nowadays, PALS is a unique nondestructive tool that has been used widely as a physical–chemical tool for directly probing the nanoatomic free volume holes sized and their concentration within a polymer 2‐5 . In PALS, when the positrons emerged from a 22 Na radioactive source, they entered the condensed medium such as polymers and quickly got thermalized by collisions with electrons of the medium.…”

Section: Introductionmentioning

confidence: 99%

Non‐fluorinated PVA/SSA proton exchange membrane studied by positron annihilation technique for fuel cell application

Awad

Abdel-Hady

Hamed

et al. 2021

Polymers for Advanced Techs

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Poly(vinyl alcohol) (PVA) with sulfosuccinic acid (SSA) membrane was prepared with different concentrations of SSA (wt.%) and thermally crosslinked successfully at 100 °C. Ion exchange capacity and proton conductivity were found to increase with increasing the SSA content in the meantime the water uptake and hydration number were declined with the rise in the degree of sulfonation. This anomalous behavior was discussed based on Nerst equation parameters which confirm the results discussion with enhancement with data of contact angle. Tensile strength results suggest the deterioration of the PVA/SSA membranes with increasing SSA content because of the chemical reaction of SSA and PVA chains. Positron annihilation results were found to enhance the electrochemical‐mechanical results of the membranes. The o‐Ps lifetime was found to increase with increasing degree of sulfonation while SO3 was working as an inhibitor agent of PS formation as o‐Ps Intensity was declined with an elevated percentage of SSA content. The o‐Ps lifetime as a function of temperature for different PVA/SSA membranes having different SSA content increased with increasing SSA content. Furthermore, the glass transition temperature of PVA/SSA membranes was found to decrease with increasing the SSA content. The results were discussed based on the free volume theory.

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Changes in free volume and gas permeation properties of poly(vinyl alcohol) nanocomposite membranes modified using cage‐structured polyhedral oligomeric silsesquioxane

Cited by 8 publications

References 51 publications

Why POSS-Type Compounds Should Be Considered Nanomodifiers, Not Nanofillers—A Polypropylene Blends Case Study

Why POSS-Type Compounds Should Be Considered Nanomodifiers, Not Nanofillers—A Polypropylene Blends Case Study

Efficient cage structured polyhedral oligomeric silsesquioxane embedded poly(vinyl alcohol) membranes: Thermal degradation and mechanical stability in hydrated condition

Non‐fluorinated PVA/SSA proton exchange membrane studied by positron annihilation technique for fuel cell application

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