Alcohol formula

New applications of polyvinyl alcohol

This article explores recent advances in the many applications of polyvinyl alcohol (PVA) and its various composites.

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PVA is a thermoplastic synthetic polymer which, unlike many other synthetic polymers, is made by the hydrolysis of poly(vinyl acetate) (PVAc). The applications of PVA have grown over the past decade due to its unique qualities, which include strong mechanical properties, chemical and thermal stability, non-toxicity, film-forming capabilities and inexpensive manufacturing costs.

PVA is used in a variety of industries, including textiles, paper, and food packaging, as well as biodegradable products such as backing rolls, adhesives, coatings, and surfactants. Besides technical uses, PVA, like other synthetic polymers, has applications in medicine and biology and has become one of the main areas of interest for polymer researchers.

Recent Applications of PVA

In recent works in Proceedings of the AIP conference, PVA was customized with bromelain (pineapple enzyme), which was used as an additive and examined in various stoichiometric ratios. A maximum tensile strength of 7.66 MPa, a maximum braking load and a three-point bend test stress of 35 N and 2.593 MPa were obtained.

By mixing glycerol and silver (AgNW) nanofibers in a PVA hydrogel, a temperature sensor resistant to freezing, water retention and moldability was created. A comparable PVA/AgNWs hydrogel sensor with biocompatibility and excellent extensibility, which can be used as strain sensors, has recently been discussed.

Heavy metals, pH, glucose, and strain can all be detected using modified PVA hydrogels as colorimetric sensors. PVA was combined with poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PEDOT:PSS) using ethylene glycol to create an antifreeze conductive hydrogel. Freeze-tolerant and conductive composite PVA/cellulose nanofibril (CNF) hydrogels have also been reported. With a glutaraldehyde-crosslinked PVA hydrogel as the electrolyte and an activated carbon fiber fabric as the electrode, a first electrochemical supercapacitor was constructed.

In another work, an acrylamide (AA) monomer was added to a PVA/H2SO4 solution to create a double-crosslinked hydrogel electrolyte for all-in-one flexible supercapacitors with energy densities of 14.2 μWh/cm2 and power densities of 0.94 mW/cm2, respectively. To produce a double crosslink network, a physically crosslinked PVA was inserted into a chemically crosslinked PEG network. The resulting PEG/PVA hydrogel not only displayed self-healing properties, but also shaped memory. In pH-varied buffer solutions, a PEG/PVA hydrogel structure could allow stable release of aspirin. These PVA hydrogels can protect the wound and prevent secondary injury caused by external environment stimuli and external mechanical force applied to the wound as a dressing, which is useful in clinical practice.

PVA Hydrogels

Artificial joints, artificial vitreous bodies, artificial muscles, artificial iris and artificial cornea could all benefit from PVA hydrogels. The PVA/agar hydrogel bio-composite becomes dense and homogeneous after soaking in an ammonium sulphate solution, with stronger H bonds between the polymers; tensile strength and toughness increased to 18.0 MPa and 42.3 MJ/m3, respectively. A slow-release fertilizer was created by combining urea in a PVA-alginate hydrogel core with an HCO3/CO32- rich alkaline acellular ureolytic culture broth. Lithium ion-conducting polymer blend electrolytes were created using PVA, poly (vinyl pyrrolidone) (PVP), and lithium acetate.

PVA/sodium polyacrylate polyblend was used to create a CO2 separation membrane. The PVA/Gl ratio of 79:30 revealed appropriate structural development, physical properties, and biological functions for OA surgery tissue formation at the subchondral bone interface. The suitability of PVA for sustained-release oral dosage forms has been proven, with advantages such as low susceptibility to pH-dependent or alcohol-induced dose dumping. It has also been effectively used to synthesize poorly water-soluble active pharmaceutical ingredients (APIs) into stable amorphous solid dispersions as a thermostable polymer. There was a 150-fold increase in solubility over crystalline API, as well as a high drug loading of up to 55% (w/w).

Future prospects

Studies have shown that 4D printed materials have the ability to change over time in response to external stimuli (temperature, external force, light, or pH), and PVA hydrogels have demonstrated the potential for 3D/4D printing for future smart applications. Conventional PVA hydrogel materials continually reveal more possibilities with the continuous development of hydrogel design and constant improvement, as well as optimization of processing and molding methods, and the future potential of PVA is immense.

Summary

As a well-known polymer in the pharmaceutical industry, PVA is gaining ground in innovative drug delivery systems. PVA appears to be suitable not only for uses in HME hot extrusion and sustained release, but also for other upcoming pharmaceutical technologies such as microneedles for transdermal delivery and 3D printing, according to reports. recent articles.

Recent studies clearly indicate that the search for new formulation technologies does not always require the invention of a new (and therefore automatically innovative) polymer, but that it is often beneficial to explore existing polymers first.

Additionally, extensive research is needed to expand the basic understanding of hydrogels, which have excellent properties such as swelling in various media, biocompatibility, temperature sensitivity, ionic strength, pH, electric fields and magnetic and other stimuli, as well as cytotoxicity, making them very promising for biomedical applications.

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References and further reading

Sundar, JS, Subramanian, R., Venkateshwaran, N., et al. Preparation and characterization of polyvinyl alcohol fibers based on bromelain. AIP Conference Proceedings 2395, 020006 (2021). https://aip.scitation.org/doi/abs/10.1063/5.0068225

Wang, M., Bai, J., Shao, K., et al. Poly(vinyl alcohol) hydrogels: old and new functional materials. International Journal of Polymer Science 2225426 (2021). https://www.hindawi.com/journals/ijps/2021/2225426/

Feldman, D., Recent Contributions of Polyvinyl Alcohol to Engineering and Medicine. J. Compos. Science. 4(4), 175 (2020). https://www.mdpi.com/2504-477X/4/4/175

Kasselkus, A., Weiskircher-Hildebrandt, E., Schornick, E., et al. Polyvinyl alcohol: rebirth of a long-lost polymer. tick, 10 (15) (2018). https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/documents/132/071/polyvinyl-alcohol-wp2488en-mk.pdf

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