Poly(vinyl alcohol) Cryogel Formation Using Biocompatible Ice Nucleating Agents

Jiang, Yanjiao; Hussain, Hidayat; Kressler, Joerg

doi:10.1002/mame.201400229

Cited by 7 publications

(4 citation statements)

References 65 publications

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“…This means that the foreign solutes of limited solubility, such as THL in the PVA–DMSO solution, act upon the freeze–thaw-induced gelation of PVA as additional porogens along with the major porogens, that is, polycrystals of the frozen solvent [1,5,9,10,58,59,60,61]. If the proposed mechanism is in operation, small particles of THL precipitate can also serve as nucleating agents with respect to solvent crystallization similarly to the limited solubility of the low molecular weight additives described by Jiang et al [62] for the case of the cryotropic gel formation of the aqueous PVA solutions.…”

Section: Resultsmentioning

confidence: 99%

Cryostructuring of Polymeric Systems. 49. Unexpected “Kosmotropic-Like” Impact of Organic Chaotropes on Freeze–Thaw-Induced Gelation of PVA in DMSO

Lozinsky

Kolosova

Michurov

et al. 2018

Gels

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Urea (URE) and guanidine hydrochloride (GHC) possessing strong chaotropic properties in aqueous media were added to DMSO solutions of poly(vinyl alcohol) (PVA) to be gelled via freeze–thaw processing. Unexpectedly, it turned out that in the case of the PVA cryotropic gel formation in DMSO medium, the URE and GHC additives caused the opposite effects to those observed in water, i.e., the formation of the PVA cryogels (PVACGs) was strengthened rather than inhibited. Our studies of this phenomenon showed that such “kosmotropic-like” effects were more pronounced for the PVACGs that were formed in DMSO in the presence of URE additives, with the effects being concentration-dependent. The additives also caused significant changes in the macroporous morphology of the cryogels; the commonly observed trend was a decrease in the structural regularity of the additive-containing samples compared to the additive-free gel sample. The viscosity measurements revealed consistent changes in the intrinsic viscosity, Huggins constant, and the excess activation heat of the viscosity caused by the additives. The results obtained evidently point to the urea-induced decrease in the solvation ability of DMSO with respect to PVA. As a result, this effect can be the key factor that is responsible for strengthening the structure formation upon the freeze–thaw gelation of this polymer in DMSO additionally containing additives such as urea, which is capable of competing with PVA for the solvent.

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Section: Resultsmentioning

confidence: 99%

Cryostructuring of Polymeric Systems. 49. Unexpected “Kosmotropic-Like” Impact of Organic Chaotropes on Freeze–Thaw-Induced Gelation of PVA in DMSO

Lozinsky

Kolosova

Michurov

et al. 2018

Gels

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“…The tack properties of PGA-based hydrogels together with their biodegradability mean that they could have significant applications as barrier to prevent postoperative adhesions that may cause medical complications. 45 Finally, the present protocol exhibits some significant benefits as being operationally simple, mild and catalyst-free, making it a promising approach for the synthesis of polyester-based networks with good water uptake capacity, which can be used for potential pharmaceutical applications such as carriers for sustained release of hydrophilic drugs 46 and biodegradable implants for controlled drug delivery. 47…”

Section: Discussionmentioning

confidence: 97%

“…It can be seen that the sample shows a high tack, which makes it suitable for typical pharmaceutical applications of hydrogels in combination with wet tissues. The tack properties of PGA‐based hydrogels together with their biodegradability mean that they could have significant applications as barrier to prevent postoperative adhesions that may cause medical complications 45 …”

Section: Discussionmentioning

confidence: 99%

Network formation by aza‐Michael addition of primary amines to vinyl end groups of enzymatically synthesized poly(glycerol adipate)

Alaneed

Golitsyn

Hauenschild

et al. 2020

Polymer International

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A highly efficient approach for the synthesis of polyester-based networks via aza-Michael addition of primary amines to ⊍,⊎-unsaturated (vinyl) end groups of poly(glycerol adipate) (PGA) was achieved. By acylation of PGA with 6-(Fmoc-amino)hexanoic acid side chains via Steglich esterification, protected amine-functionalized PGA was obtained. This was followed by the removal of fluorenylmethyloxycarbonyl (Fmoc) protecting groups and the synthesis of PGA-based networks under catalyst-free conditions. The successful conjugate addition of primary amines to vinyl end groups and network formation were confirmed using 13 C magic angle spinning NMR and Fourier transform infrared spectroscopy. Network heterogeneity and defects were quantitatively investigated using 1 H double-quantum NMR spectroscopy. Finally, a hydrogel was prepared with potential biomedical applications. Supporting information may be found in the online version of this article.

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“…However, the problem with this type of BPCM is the super cooling at lower temperatures that limits their usage in the suitable range for building applications. Another problem is the volume expansion during phase transition, which requires a large matrix volume [22,35,36]. Some sugar alcohols, e.g., D-mannitol, myo-inositol, and galacitol were studied as potential PCMs.…”

Section: Polyolsmentioning

confidence: 99%

Bio-Based Phase Change Materials Incorporated in Lignocellulose Matrix for Energy Storage in Buildings—A Review

2020

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Due to growing consciousness regarding the environmental impact of fossil-based and non-sustainable materials in construction and building applications, there have been an increasing interest in bio-based and degradable materials in this industry. Due to their excellent chemical and thermo-physical properties for thermal energy storage, bio-based phase change materials (BPCMs) have started to attract attention worldwide for low to medium temperature applications. The ready availability, renewability, and low carbon footprint of BPCMs make them suitable for a large spectrum of applications. Up to now, most of the BPCMs have been incorporated into inorganic matrices with only a few attempts to set the BPCMs into bio-matrices. The current paper is the first comprehensive review on BPCMs incorporation in wood and wood-based materials, as renewable and sustainable materials in buildings, to enhance the thermal mass in the environmentally-friendly buildings. In the paper, the aspects of choosing BPCMs, bio-based matrices, phase change mechanisms and their combination, interpretation of life cycle analyses, and the eventual challenges of using these materials are presented and discussed.

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Poly(vinyl alcohol) Cryogel Formation Using Biocompatible Ice Nucleating Agents

Cited by 7 publications

References 65 publications

Cryostructuring of Polymeric Systems. 49. Unexpected “Kosmotropic-Like” Impact of Organic Chaotropes on Freeze–Thaw-Induced Gelation of PVA in DMSO

Cryostructuring of Polymeric Systems. 49. Unexpected “Kosmotropic-Like” Impact of Organic Chaotropes on Freeze–Thaw-Induced Gelation of PVA in DMSO

Network formation by aza‐Michael addition of primary amines to vinyl end groups of enzymatically synthesized poly(glycerol adipate)

Bio-Based Phase Change Materials Incorporated in Lignocellulose Matrix for Energy Storage in Buildings—A Review

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