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Vinyl alcohol

About: Vinyl alcohol is a research topic. Over the lifetime, 13839 publications have been published within this topic receiving 315464 citations. The topic is also known as: Ethenol & Hydroxyethene.


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Journal ArticleDOI

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TL;DR: In this article, the role of dynamic swelling and the dissolution of the polymer matrix on the release mechanism was discussed, as well as the effect of the tracer/excipient ratio on the poly(vinyl alcohol) release profile.
Abstract: Porous hydrophilic discs were prepared from two grades of poly(vinyl alcohol) of varying degree of hydrolysis. The influence of the molecular size of the tracer used (potassium chloride, phenylpropanolamine hydrochloride and bovine serum albumin), that of the addition of a second water-soluble polymer poly(N-vinyl-2-pyrrolidone) and poly(ethylene glycol)) and the effect of the tracer/excipient ratio on the release profile were examined. Finally the role of the dynamic swelling and the dissolution of the polymer matrix on the release mechanism are discussed.

3,906 citations

Journal ArticleDOI

[...]

TL;DR: Hydrogel nanoparticles have gained considerable attention in recent years as one of the most promising nanoparticulate drug delivery systems owing to their unique potentials via combining the characteristics of a hydrogel system with a nanoparticle, each with its own advantages and drawbacks.
Abstract: Hydrogel nanoparticles have gained considerable attention in recent years as one of the most promising nanoparticulate drug delivery systems owing to their unique potentials via combining the characteristics of a hydrogel system (e.g., hydrophilicity and extremely high water content) with a nanoparticle (e.g., very small size). Several polymeric hydrogel nanoparticulate systems have been prepared and characterized in recent years, based on both natural and synthetic polymers, each with its own advantages and drawbacks. Among the natural polymers, chitosan and alginate have been studied extensively for preparation of hydrogel nanoparticles and from synthetic group, hydrogel nanoparticles based on poly (vinyl alcohol), poly (ethylene oxide), poly (ethyleneimine), poly (vinyl pyrrolidone), and poly-N-isopropylacrylamide have been reported with different characteristics and features with respect to drug delivery. Regardless of the type of polymer used, the release mechanism of the loaded agent from hydrogel nanoparticles is complex, while resulting from three main vectors, i.e., drug diffusion, hydrogel matrix swelling, and chemical reactivity of the drug/matrix. Several crosslinking methods have been used in the way to form the hydrogel matix structures, which can be classified in two major groups of chemically- and physically-induced crosslinking.

1,482 citations

Journal ArticleDOI

[...]

Jiajie Liang1, Yi Huang1, Long Zhang1, Yan Wang1, Yanfeng Ma1, Tianyin Guo1, Yongsheng Chen1 
TL;DR: In this paper, the preparation of polyvinyl alcohol (PVA) nanocomposites with graphene oxide (GO) using a simple water solution processing method is reported, and efficient load transfer is found between the nanofiller graphene and matrix PVA and the mechanical properties of the graphene-based nanocompositionite with molecule-level dispersion are significantly improved.
Abstract: Despite great recent progress with carbon nanotubes and other nanoscale fillers, the development of strong, durable, and cost-efficient multifunctional nanocomposite materials has yet to be achieved. The challenges are to achieve molecule-level dispersion and maximum interfacial interaction between the nanofiller and the matrix at low loading. Here, the preparation of poly(vinyl alcohol) (PVA) nanocomposites with graphene oxide (GO) using a simple water solution processing method is reported. Efficient load transfer is found between the nanofiller graphene and matrix PVA and the mechanical properties of the graphene-based nanocomposite with molecule-level dispersion are significantly improved. A 76% increase in tensile strength and a 62% improvement of Young's modulus are achieved by addition of only 0.7 wt% of GO. The experimentally determined Young's modulus is in excellent agreement with theoretical simulation.

1,403 citations

Journal ArticleDOI

[...]

TL;DR: In this article, a facial aqueous solution was used to extract fully exfoliated graphene nanosheets and polyvinyl alcohol (PVA) for the preparation of polymer nanocomposites.
Abstract: Graphene, flat carbon nanosheets, has generated huge activity in many areas of science and engineering due to its unprecedented physical and chemical properties. With the development of wide-scale applicability including facile synthesis and high yield, this exciting material is ready for its practical application in the preparation of polymer nanocomposites. Here we report that nanocomposites based on fully exfoliated graphene nanosheets and poly(vinyl alcohol) (PVA) are prepared via a facial aqueous solution. A significant enhancement of mechanical properties of the graphene/PVA composites is obtained at low graphene loading; that is, a 150% improvement of tensile strength and a nearly 10 times increase of Young’s modulus are achieved at a graphene loading of 1.8 vol %. The comparison between the experimental results and theoretical simulation for Young’s modulus indicates that the graphene nanosheets in polymer matrix are mostly dispersed randomly in the nanocomposite films.

1,201 citations

Book ChapterDOI

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TL;DR: In this article, a review of previous work in the development of freezing and thawing processes focusing on the implications of such materials for a variety of applications is presented, and future directions involving the further development of freeze/thawed PVA hydrogels are addressed.
Abstract: Poly(vinyl alcohol) (PVA) is a polymer of great interest because of its many desirable characteristics specifically for various pharmaceutical and biomedical applications. The crystalline nature of PVA has been of specific interest particularly for physically cross-linked hydrogels prepared by repeated cycles of freezing and thawing. This review includes details on the structure and properties of PVA, the synthesis of its hydrogels, the crystallization of PVA, as well as its applications. An analysis of previous work in the development of freezing and thawing processes is presented focusing on the implications of such materials for a variety of applications. PVA blends that have been developed with enhanced properties for specific applications will also be discussed briefly. Finally, the future directions involving the further development of freeze/thawed PVA hydrogels are addressed.

1,175 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023385
2022717
2021506
2020578
2019570
2018620