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

Swapna, Valiya Parambath; Krishnan, Meera R.; Abhisha, Vakkoottil Sivadasan; Stephen, Ranimol

doi:10.1002/app.51377

Cited by 5 publications

(2 citation statements)

References 39 publications

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“…48 The fourth stage was observed at a temperature above 400 °C (stage D) and involved the degradation of carbonaceous materials yielded in the former stages. 49 The addition of water greatly influenced the weight loss in the first stage, owing to the evaporation of water, whereas similar degradation behaviors were observed in the subsequent stages. This indicated that water could be removed in the first stage, thus exerting minimal influence on the intrinsic decomposition process of PVA.…”

Section: Thermal Analysis Of Pva Pelletsmentioning

confidence: 71%

“…The largest DTG peak in the range of 300–400 °C was related to the third stage (stage C), where chain scission of PVA molecules took place . The fourth stage was observed at a temperature above 400 °C (stage D) and involved the degradation of carbonaceous materials yielded in the former stages . The addition of water greatly influenced the weight loss in the first stage, owing to the evaporation of water, whereas similar degradation behaviors were observed in the subsequent stages.…”

Section: Resultsmentioning

confidence: 86%

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Green Preparation of High-Performance Poly(Vinyl Alcohol) Film by Combining Gel-Like Extrusion and Biaxial Stretching

Zeng,

Wang,

et al. 2024

Ind. Eng. Chem. Res.

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Poly(vinyl alcohol) (PVA), which has the lowest oxygen permeability among various commercial polymers, shows great potential in high-barrier packaging applications. However, the difficulty in thermal processing of PVA inhibits its use in barrier packaging because the mainstream technique for producing PVA film, i.e., solution casting, has the disadvantages of low production efficiency, long production cycle, and high operating costs. Herein, inspired by the gel spinning of PVA fibers, a moderate amount of water was utilized to achieve the gel-like extrusion of PVA, followed by biaxial stretching, to produce high-performance PVA films. The introduced water disrupted the intra-and intermacromolecular interactions in PVA and formed new hydrogen bonds with PVA molecules. As the water content increased, the proportion of nonfreezable bound water decreased and the percentage of freezable bound water increased, leading to a decrease in the melting point and glass transition temperature and an increase in the melt flowability of PVA. The extruded PVA containing 40% water exhibited an elongation at break of 504.9%, implying good stretchability. After biaxial stretching, the film strength and modulus reached 111.0 MPa and 5.4 GPa, respectively, attributed to the formed highly ordered lamellar structures and greatly improved crystallinity. More importantly, the generated well-ordered crystals provided physical barriers to block oxygen gas permeation, endowing the film with an ultralow oxygen permeability coefficient of 1.89 × 10 −18 cm 3 •cm/(cm 2 •s•Pa) and a high barrier improvement factor of 68.3, compared to commercial PET films. This high-strength and high-barrier PVA film is expected to be widely used in the packaging of food, tobacco, electronic products, textiles, and other items.

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Section: Thermal Analysis Of Pva Pelletsmentioning

confidence: 71%

Section: Resultsmentioning

confidence: 86%

Green Preparation of High-Performance Poly(Vinyl Alcohol) Film by Combining Gel-Like Extrusion and Biaxial Stretching

Zeng,

Wang,

et al. 2024

Ind. Eng. Chem. Res.

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Pervaporation performance of poly(vinyl alcohol)‐graft‐poly(N‐hydroxymethyl acrylamide) membranes for dehydration of isopropyl alcohol‐water mixture

Baysak

Işıklan

2021

J of Applied Polymer Sci

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In the present work, poly(N‐hydroxymethyl acrylamide) grafted poly(vinyl alcohol) (PVA‐g‐PNHMA) membranes were developed for the dehydration of isopropyl alcohol (IPA) by the use of pervaporation method. The PVA‐g‐PNHMA membranes have been synthesized and their chemical composition and morphology have been characterized by Fourier transform infrared spectroscopy, 13C‐nuclear magnetic resonance spectroscopy, X‐ray diffractometry, differential scanning calorimetry, thermogravimetric analysis, and field emission scanning electron microscopy. The impacts of numerous factors such as temperature, feed concentration as well as membrane thickness on their pervaporation performance were investigated and the optimal conditions were found. With the increase in the grafting percentage of the PVA‐g‐PNHMA membrane, both flux and separation factor also increase. The PVA‐g‐PNHMA membrane with a grafting percentage of 34% revealed the best separation factor of 362 with a flux of 0.0085 kg/m2.h for 12.6% mass of water in the feed solution. It has also been found that swelling behaviors of the membranes are consistent with all pervaporation results. Besides, permeation and diffusion activation energies were determined as 23.69 and 29.21 kJ/mol from the change of permeation flux with temperature. Based on the obtained outcomes, it is obvious that PVA‐g‐PNHMA membranes are quite efficient in the separation of IPA/water mixture via pervaporation.

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Synergistic effect of hybrid fillers on the thermal degradation of natural rubber: stability and kinetic studies

Abhisha,

‬Sisanth,

Selvin Thomas

et al. 2024

Polym. Bull.

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

Cited by 5 publications

References 39 publications

Green Preparation of High-Performance Poly(Vinyl Alcohol) Film by Combining Gel-Like Extrusion and Biaxial Stretching

Green Preparation of High-Performance Poly(Vinyl Alcohol) Film by Combining Gel-Like Extrusion and Biaxial Stretching

Pervaporation performance of poly(vinyl alcohol)‐graft‐poly(N‐hydroxymethyl acrylamide) membranes for dehydration of isopropyl alcohol‐water mixture

Synergistic effect of hybrid fillers on the thermal degradation of natural rubber: stability and kinetic studies

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