2023

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17 pages, 3623 KiB

Open AccessArticle

Epoxidized Soybean-Oils-Based Pressure-Sensitive Adhesives with Di-Hydroxylated Soybean-Oils Copolymerizing and Antioxidant Grafting

by Yongyan Kuang, Wenlong Li, Shuli Xie, Weijian Gong, Zihan Ye, Yiming Wang, Dan Peng and Jun Li

Polymers 2023, 15(12), 2709; https://doi.org/10.3390/polym15122709 - 16 Jun 2023

Cited by 1 | Viewed by 1255

Abstract

Vegetable-oils-based pressure-sensitive adhesives (PSAs) are being developed as a substitute for petrochemical-based PSAs for application in daily life. However, vegetable-oils-based PSAs face the problems of unsatisfactory binding strengths and easy aging. In this work, the grafting of antioxidants (tea polyphenol palmitates, caffeic acid, [...] Read more.

Vegetable-oils-based pressure-sensitive adhesives (PSAs) are being developed as a substitute for petrochemical-based PSAs for application in daily life. However, vegetable-oils-based PSAs face the problems of unsatisfactory binding strengths and easy aging. In this work, the grafting of antioxidants (tea polyphenol palmitates, caffeic acid, ferulic acid, gallic acid, butylated hydroxytoluene, tertiary butylhydroquinone, butylated hydroxyanisole, propyl gallate (PG), tea polyphenols) was introduced into an epoxidized soybean oils (ESO)/di-hydroxylated soybean oils (DSO)-based PSA system to improve the binding strengths and aging-resistant properties. PG was screened out as the most suitable antioxidant in the ESO/DSO-based PSA system. Under optimal conditions (ESO/DSO mass ratio of 9/3, 0.8% PG, 55% rosin ester (RE), 8% phosphoric acid (PA), 50 °C, and 5 min), the peel adhesion, tack, and shear adhesion of the PG-grafted ESO/DSO-based PSA increased to 1.718 N/cm, 4.62 N, and >99 h, respectively, in comparison with the control (0.879 N/cm, 3.59 N, and 13.88 h), while peel adhesion residue reduced to 12.16% in comparison with the control (484.07%). The thermal stability of the ESO/DSO-based PSA was enhanced after PG grafting. PG, RE, PA, and DSO were partially crosslinked in the PSA system, with the rest being free in the network structures. Thus, antioxidant grafting is a feasible method for improving the binding strengths and aging-resistant properties of vegetable-oils-based PSAs. Full article

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20 pages, 12958 KiB

Open AccessArticle

Anionic Polysaccharide Cryogels: Interaction and In Vitro Behavior of Alginate–Gum Arabic Composites

by Alexandra Feraru, Zsejke-Réka Tóth, Marieta Mureșan-Pop, Monica Baia, Tamás Gyulavári, Emőke Páll, Romulus V. F. Turcu, Klára Magyari and Lucian Baia

Polymers 2023, 15(8), 1844; https://doi.org/10.3390/polym15081844 - 11 Apr 2023

Cited by 4 | Viewed by 1913

Abstract

In the present study, polysaccharide-based cryogels demonstrate their potential to mimic a synthetic extracellular matrix. Alginate-based cryogel composites with different gum arabic ratios were synthesized by an external ionic cross-linking protocol, and the interaction between the anionic polysaccharides was investigated. The structural features [...] Read more.

In the present study, polysaccharide-based cryogels demonstrate their potential to mimic a synthetic extracellular matrix. Alginate-based cryogel composites with different gum arabic ratios were synthesized by an external ionic cross-linking protocol, and the interaction between the anionic polysaccharides was investigated. The structural features provided by FT-IR, Raman, and MAS NMR spectra analysis indicated that a chelation mechanism is the main process linking the two biopolymers. In addition, SEM investigations revealed a porous, interconnected, and well-defined structure suitable as a scaffold in tissue engineering. The in vitro tests confirmed the bioactive character of the cryogels through the development of the apatite layer on the surface of the samples after immersion in simulated body fluid, identifying the formation of a stable phase of calcium phosphate and a small amount of calcium oxalate. Cytotoxicity tests performed on fibroblast cells demonstrated the non-toxic effect of alginate–gum arabic cryogel composites. In addition, an increase in flexibility was noted for samples with a high gum arabic content, which determines an appropriate environment to promote tissue regeneration. The newly obtained biomaterials that exhibit all these properties can be successfully involved in the regeneration of soft tissues, wound management, or controlled drug release systems. Full article

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15 pages, 12356 KiB

Open AccessArticle

Preparation and Properties of Bimetallic Chitosan Spherical Microgels

by Andrea Lončarević, Karla Ostojić, Inga Urlić and Anamarija Rogina

Polymers 2023, 15(6), 1480; https://doi.org/10.3390/polym15061480 - 16 Mar 2023

Cited by 2 | Viewed by 1911

Abstract

The aim of this work was to prepare bimetallic chitosan microgels with high sphericity and investigate the influences of metal-ion type and content on the size, morphology, swelling, degradation and biological properties of microgels. Amino and hydroxyl groups of chitosan (deacetylation degree, DD [...] Read more.

The aim of this work was to prepare bimetallic chitosan microgels with high sphericity and investigate the influences of metal-ion type and content on the size, morphology, swelling, degradation and biological properties of microgels. Amino and hydroxyl groups of chitosan (deacetylation degree, DD, of 83.2% and 96.9%) served as ligands in the Cu²⁺–Zn²⁺/chitosan complexes with various contents of cupric and zinc ions. The electrohydrodynamic atomization process was used to produce highly spherical microgels with a narrow size distribution and with surface morphology changing from wrinkled to smooth by increasing Cu²⁺ ions’ quantity in bimetallic systems for both used chitosans. The size of the bimetallic chitosan particles was estimated to be between 60 and 110 µm for both used chitosans, and FTIR spectroscopy indicated the formation of complexes through physical interactions between the chitosans’ functional groups and metal ions. The swelling capacity of bimetallic chitosan particles decreases as the DD and copper (II) ion content increase as a result of stronger complexation with respect to zinc (II) ions. Bimetallic chitosan microgels showed good stability during four weeks of enzymatic degradation, and bimetallic systems with smaller amounts of Cu²⁺ ions showed good cytocompatibility for both used chitosans. Full article

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2022

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17 pages, 4102 KiB

Open AccessArticle

Chitosan–Gelatin Films: Plasticizers/Nanofillers Affect Chain Interactions and Material Properties in Different Ways

by Qingfei Duan, Ying Chen, Long Yu and Fengwei Xie

Polymers 2022, 14(18), 3797; https://doi.org/10.3390/polym14183797 - 11 Sep 2022

Cited by 6 | Viewed by 3004

Abstract

Biopolymers, which are biodegradable and inherently functional, have high potential for specialized applications (e.g., disposable and transient systems and biomedical treatment). For this, it is important to create composite materials with precisely defined chain interactions and tailored properties. This work shows that for [...] Read more.

Biopolymers, which are biodegradable and inherently functional, have high potential for specialized applications (e.g., disposable and transient systems and biomedical treatment). For this, it is important to create composite materials with precisely defined chain interactions and tailored properties. This work shows that for a chitosan–gelatin material, both glycerol and isosorbide are effective plasticizers, but isosorbide could additionally disrupt the polyelectrolyte complexation (PEC) between the two biopolymers, which greatly impacts the glass transition temperature (T_g), mechanical properties, and water absorption. While glycerol-plasticized samples without nanofiller or with graphene oxide (GO) showed minimal water uptake, the addition of isosorbide and/or montmorillonite (MMT) made the materials hydrolytically unstable, likely due to disrupted PEC. However, these samples showed an opposite trend in surface hydrophilicity, which means surface chemistry is controlled differently from chain structure. This work highlights different mechanisms that control the different properties of dual-biopolymer systems and provides an updated definition of biopolymer plasticization, and thus could provide important knowledge for the future design of biopolymer composite materials with tailored surface hydrophilicity, overall hygroscopicity, and mechanical properties that meet specific application needs. Full article

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18 pages, 5127 KiB

Open AccessArticle

Cryostructuring of Polymeric Systems: 62 Preparation and Characterization of Alginate/Chondroitin Sulfate Cryostructurates Loaded with Antimicrobial Substances

by Olga I. Vernaya, Andrey N. Ryabev, Tatyana I. Shabatina, Daria L. Karlova, Andrey V. Shabatin, Lyudmila N. Bulatnikova, Alexander M. Semenov, Mikhail Ya. Melnikov and Vladimir I. Lozinsky

Polymers 2022, 14(16), 3271; https://doi.org/10.3390/polym14163271 - 11 Aug 2022

Cited by 4 | Viewed by 2209

Abstract

Targeted drug release is a significant research focus in the development of drug delivery systems and involves a biocompatible polymeric carrier and certain medicines. Cryostructuring is a suitable approach for the preparation of efficient macroporous carriers for such drug delivery systems. In the [...] Read more.

Targeted drug release is a significant research focus in the development of drug delivery systems and involves a biocompatible polymeric carrier and certain medicines. Cryostructuring is a suitable approach for the preparation of efficient macroporous carriers for such drug delivery systems. In the current study, the cryogenically structured carriers based on alginate/chondroitin sulfate mixtures were prepared and their physicochemical properties and their ability to absorb/release the bactericides were evaluated. The swelling parameters of the polysaccharide matrix, the amount of the tightly bound water in the polymer and the sulfur content were measured. In addition, FTIR and UV spectroscopy, optical and scanning microscopy, as well as a standard disk diffusion method for determining antibacterial activity were used. It was shown that alginate/chondroitin sulfate concentration and their ratios were significant factors influencing the swelling properties and the porosity of the resultant cryostructurates. It was demonstrated that the presence of chondroitin sulfate in the composition of a polymeric matrix slowed down the release of the aminoglycoside antibiotic gentamicin. In the case of the NH₂-free bactericide, dioxidine, the release was almost independent of the presence of chondroitin sulfate. This trend was also registered for the antibacterial activity tests against the Escherichia coli bacteria, when examining the drug-loaded biopolymeric carriers. Full article

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2021

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1 pages, 164 KiB

Open AccessCorrection

Correction: Qiao et al. Microstructure and Mechanical/Hydrophilic Features of Agar-Based Films Incorporated with Konjac Glucomannan. Polymers 2019, 11, 1952

by Dongling Qiao, Wenyao Tu, Lei Zhong, Zhong Wang, Binjia Zhang and Fatang Jiang

Polymers 2021, 13(19), 3352; https://doi.org/10.3390/polym13193352 - 30 Sep 2021

Cited by 1 | Viewed by 928

Abstract

The authors wish to make the following correction to this paper [...] Full article

2019

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12 pages, 4128 KiB

Open AccessArticle

Microstructure and Mechanical/Hydrophilic Features of Agar-Based Films Incorporated with Konjac Glucomannan

by Dongling Qiao, Wenyao Tu, Lei Zhong, Zhong Wang, Binjia Zhang and Fatang Jiang

Polymers 2019, 11(12), 1952; https://doi.org/10.3390/polym11121952 - 27 Nov 2019

Cited by 32 | Viewed by 3690 | Correction

Abstract

Different characterization methods spanning length scales from molecular to micron scale were applied to inspect the microstructures and mechanical/hydrophilic features of agar/konjac glucomannan (KGM) films prepared under different drying temperatures (40 and 60 °C). Note that the lower preparation temperature (40 °C) could [...] Read more.

Different characterization methods spanning length scales from molecular to micron scale were applied to inspect the microstructures and mechanical/hydrophilic features of agar/konjac glucomannan (KGM) films prepared under different drying temperatures (40 and 60 °C). Note that the lower preparation temperature (40 °C) could increase the strength and elongation of agar/KGM films at high KGM levels (18:82 wt/wt KGM-agar, or higher). This was related to the variations in the film multi-scale structures with the increment of KGM content: the reduced crystallinity, the increased perfection of nanoscale orders at some KGM amounts, and the negligibly-changed morphology and molecular chemical structure under 40 °C preparation temperature. These structural changes initially decreased the film tensile strength, and subsequently increased the film strength and elongation with increasing KGM content. Moreover, under the higher drying temperature (60 °C), the increased KGM content could concurrently reduce the strength and elongation for the films, associated with probable phase separations on nano and smaller scales. In addition, the increased KGM amount tended to make the film more hydrophilic, whereas the changes in the film structures did not dominantly affect the changing trend of hydrophilicity. Full article

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9 pages, 3681 KiB

Open AccessArticle

Electric Volume Resistivity for Biopolyimide Using 4,4′-Diamino-α-truxillic acid and 1,2,3,4-Cyclobutanetetracarboxylic dianhydride

by Shunsuke Kato, Fitri Adila Amat Yusof, Toyohiro Harimoto, Kenji Takada, Tatsuo Kaneko, Mika Kawai and Tetsu Mitsumata

Polymers 2019, 11(10), 1552; https://doi.org/10.3390/polym11101552 - 24 Sep 2019

Cited by 10 | Viewed by 4355

Abstract

Biopolyimides poly(ATA-CBDA), made from of 4,4′-diamino-α-truxillic acid dimethyl ester (ATA) and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), is synthesized and measured its electric volume resistivity at various experimental conditions. The effects of film size, thickness, drying time, and the electric field strength on electric resistivity are [...] Read more.

Biopolyimides poly(ATA-CBDA), made from of 4,4′-diamino-α-truxillic acid dimethyl ester (ATA) and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), is synthesized and measured its electric volume resistivity at various experimental conditions. The effects of film size, thickness, drying time, and the electric field strength on electric resistivity are investigated and compared with polyimide (Kapton). The electric resistivity for all polyimide and biopolyimide are distributed in the range of 10¹⁵–10¹⁶ Ωcm, which shows that biopolyimide has high electrical insulation as well as polyimide. The electric resistivity strongly depends on film thickness, which suggests that electric resistivity is a function of electric field strength. The critical electric field for polyimide and biopolyimide films are determined to be 5.8 × 10⁷ V/m and 3.2 × 10⁷ V/m, respectively. Humidity was found to strongly affect the electric resistivity; ~10¹⁶ Ωcm at 34% RH and ~10¹³ Ωcm at 60% RH for both polyimide and biopolyimide films. Full article

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10 pages, 3129 KiB

Open AccessArticle

Fluorescent and Mechanical Properties of Silicon Quantum Dots Modified Sodium Alginate-Carboxymethylcellulose Sodium Nanocomposite Bio-Polymer Films

by Yali Ji, Huimin Zhang, Canfu Zhang, Zhiyi Quan, Min Huang and Lili Wang

Polymers 2019, 11(9), 1476; https://doi.org/10.3390/polym11091476 - 09 Sep 2019

Cited by 9 | Viewed by 3070

Abstract

Highly luminescent silicon quantum dots (SiQDs) were prepared via one-pot hydrothermal route. Furthermore, the optimal synthetic conditions, dependence of the emission spectrum on the excitation wavelength and fluorescent stability of SiQDs were investigated by fluorescence spectroscopy. SiQDs exhibited bright blue fluorescence, and photoluminescence [...] Read more.

Highly luminescent silicon quantum dots (SiQDs) were prepared via one-pot hydrothermal route. Furthermore, the optimal synthetic conditions, dependence of the emission spectrum on the excitation wavelength and fluorescent stability of SiQDs were investigated by fluorescence spectroscopy. SiQDs exhibited bright blue fluorescence, and photoluminescence (PL) lifetime is 10.8 ns when excited at 325 nm. The small-sized SiQDs (~3.3 nm) possessed uniform particle size, crystal lattice spacing of 0.31 nm and silicon (111), (220) crystal planes. Luminescent SiQDs/sodium alginate (SA)-carboxymethylcellulose sodium (CMC) nanocomposite bio-polymer films were successfully fabricated by incorporating SiQDs into the SA-CMC matrix. Meanwhile, SiQDs not only impart strong fluorescence to the polymer, but also make the composite films have favorable toughness. Full article

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17 pages, 4048 KiB

Open AccessArticle

Influence of Annealing and Biaxial Expansion on the Properties of Poly(l-Lactic Acid) Medical Tubing

by Brian Dillon, Patrick Doran, Evert Fuenmayor, Andrew V. Healy, Noel M. Gately, Ian Major and John G. Lyons

Polymers 2019, 11(7), 1172; https://doi.org/10.3390/polym11071172 - 11 Jul 2019

Cited by 16 | Viewed by 3574

Abstract

Poly-l-lactic acid (PLLA) is one of the most common bioabsorbable materials in the medical device field. However, its use in load-bearing applications is limited due to its inferior mechanical properties when compared to many of the competing metal-based permanent and bioabsorbable [...] Read more.

Poly-l-lactic acid (PLLA) is one of the most common bioabsorbable materials in the medical device field. However, its use in load-bearing applications is limited due to its inferior mechanical properties when compared to many of the competing metal-based permanent and bioabsorbable materials. The objective of this study was to directly compare the influence of both annealing and biaxial expansion processes to improve the material properties of PLLA. Results showed that both annealing and biaxial expansion led to an overall increase in crystallinity and that the crystallites formed during both processes were in the α’ and α forms. 2D-WAXS patterns showed that the preferred orientation of crystallites formed during annealing was parallel to the circumferential direction. While biaxial expansion resulted in orientation in both axial and circumferential directions, with relatively equal sized crystals in both directions, Da (112 Å) and Dc (97 Å). The expansion process had the most profound effect on mechanical performance, with a 65% increase in Young’s modulus, a 45% increase in maximum tensile stress and an 18-fold increase in strain at maximum load. These results indicate that biaxially expanding PLLA at a temperature above T_cc is possible, due to the high strain rates associated with stretch blow moulding. Full article

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12 pages, 4670 KiB

Open AccessArticle

Liquefaction of Peanut Shells with Cation Exchange Resin and Sulfuric Acid as Dual Catalyst for the Subsequent Synthesis of Rigid Polyurethane Foam

by Qinqin Zhang, Weisheng Chen, Guojuan Qu, Xiaoqi Lin, Dezhi Han, Xiaofei Yan and Heng Zhang

Polymers 2019, 11(6), 993; https://doi.org/10.3390/polym11060993 - 04 Jun 2019

Cited by 12 | Viewed by 3938

Abstract

The conversion of lignocellulosic biomass from renewable raw materials to high value-added fine chemicals expanded their application in biodegradable polymers materials synthesis, such as polyurethanes and phenolic resin, etc. In this work, the strong-acid cation exchange resin and sulfuric acid as the dual [...] Read more.

The conversion of lignocellulosic biomass from renewable raw materials to high value-added fine chemicals expanded their application in biodegradable polymers materials synthesis, such as polyurethanes and phenolic resin, etc. In this work, the strong-acid cation exchange resin and sulfuric acid as the dual catalyst offered an effective way to catalyze the liquefaction reaction of the peanut shells. The properties of liquefied products were characterized by means of hydroxyl value, viscosity and solubility tests, while the properties of peanut shells and liquefaction residue were analyzed by means of ATR-FTIR, TG and SEM techniques. The results indicated that the liquefied products could be completely dissolved in deionized water, methanol and polyethylene glycol, respectively, and they could be a preferable substitution of petrochemical polyols as soft segments to synthesize the rigid polyurethane foams. Moreover, the cellulose and hemicellulose in the peanut shells were easily decomposed into smaller molecules via the breakage of the C–O bond besides five-membered and hexatomic ring, while the lignin could be degraded via the breakage of the C–O chemical bonds of β-O-4, 4-O-5 and dibenzodioxocin units. The fabricated rigid polyurethane (RPU) foam, containing higher percentage of open pores with uniform size, can be potentially utilized for flower mud and sound-absorbing materials. Full article

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17 pages, 4279 KiB

Open AccessArticle

The Influence of Low Shear Microbore Extrusion on the Properties of High Molecular Weight Poly(l-Lactic Acid) for Medical Tubing Applications

by Brian Dillon, Patrick Doran, Evert Fuenmayor, Andrew V. Healy, Noel M. Gately, Ian Major and John G. Lyons

Polymers 2019, 11(4), 710; https://doi.org/10.3390/polym11040710 - 18 Apr 2019

Cited by 11 | Viewed by 5018

Abstract

Biodegradable polymers play a crucial role in the medical device field, with a broad range of applications such as suturing, drug delivery, tissue engineering, scaffolding, orthopaedics, and fixation devices. Poly-l-lactic acid (PLLA) is one of the most commonly used and investigated [...] Read more.

Biodegradable polymers play a crucial role in the medical device field, with a broad range of applications such as suturing, drug delivery, tissue engineering, scaffolding, orthopaedics, and fixation devices. Poly-l-lactic acid (PLLA) is one of the most commonly used and investigated biodegradable polymers. The objective of this study was to determine the influence low shear microbore extrusion exerts on the properties of high molecular weight PLLA for medical tubing applications. Results showed that even at low shear rates there was a considerable reduction in molecular weight (M_n = 7–18%) during processing, with a further loss (M_n 11%) associated with resin drying. An increase in melt residence time from ~4 mins to ~6 mins, translated into a 12% greater reduction in molecular weight. The degradation mechanism was determined to be thermal and resulted in a ~22-fold increase in residual monomer. The differences in molecular weight between both batches had no effect on the materials thermal or morphological properties. However, it did affect its mechanical properties, with a significant impact on tensile strength and modulus. Interestingly there was no effect on the elongational proprieties of the tubing. There was also an observed temperature-dependence of mechanical properties below the glass transition temperature. Full article

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15 pages, 4302 KiB

Open AccessArticle

DNA Compaction and Charge Neutralization Regulated by Divalent Ions in very Low pH Solution

by Tianyong Gao, Wei Zhang, Yanwei Wang and Guangcan Yang

Polymers 2019, 11(2), 337; https://doi.org/10.3390/polym11020337 - 15 Feb 2019

Cited by 20 | Viewed by 3922

Abstract

DNA conformation is strongly dependent on the valence of counterions in solution, and a valence of at least three is needed for DNA compaction. Recently, we directly demonstrated DNA compaction and its regulation, mediated by divalent cations, by lowering the pH of a [...] Read more.

DNA conformation is strongly dependent on the valence of counterions in solution, and a valence of at least three is needed for DNA compaction. Recently, we directly demonstrated DNA compaction and its regulation, mediated by divalent cations, by lowering the pH of a solution. In the present study, we found that the critical electrophoretic mobility of DNA is promoted to around −1.0 × 10⁻⁴ cm² V⁻¹ s⁻¹ to incur DNA compaction or condensation in a tri- and tetravalent counterions solution, corresponding to an about 89% neutralized charge fraction of DNA. This is also valid for DNA compaction by divalent counterions in a low pH solution. It is notable that the critical charge neutralization of DNA for compaction is only about 1% higher than the saturated charge fraction of DNA in a mild divalent ion solution. We also found that DNA compaction by divalent cations at low pH is weakened and even decondensed with an increasing concentration of counterions. Full article

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11 pages, 6567 KiB

Open AccessArticle

Functional Porous Carboxymethyl Cellulose/Cellulose Acetate Composite Microspheres: Preparation, Characterization, and Application in the Effective Removal of HCN from Cigarette Smoke

by Peijian Sun, Song Yang, Xuehui Sun, Yipeng Wang, Lining Pan, Hongbo Wang, Xiaoyu Wang, Jizhao Guo and Cong Nie

Polymers 2019, 11(1), 181; https://doi.org/10.3390/polym11010181 - 21 Jan 2019

Cited by 15 | Viewed by 5342

Abstract

To selectively reduce the yield of hydrogen cyanide (HCN) in the cigarette smoke, functional porous carboxymethyl cellulose/cellulose acetate (CMC/CA) composite microspheres were prepared via the double emulsion-solvent evaporation method. Cupric ions, which have a high complexing ability toward HCN, were introduced to the [...] Read more.

To selectively reduce the yield of hydrogen cyanide (HCN) in the cigarette smoke, functional porous carboxymethyl cellulose/cellulose acetate (CMC/CA) composite microspheres were prepared via the double emulsion-solvent evaporation method. Cupric ions, which have a high complexing ability toward HCN, were introduced to the CMC/CA composite microspheres during the fabrication process via an in situ ion cross-link method. The microspheres were characterized using nitrogen adsorption, mercury intrusion porosimetry, and scanning electron microscopy (SEM). The microspheres have a predominantly macroporous structure indicating weak physisorption properties, but sufficient functional cupric ion groups to selectively adsorb HCN. With these CMC/CA microspheres as filter additives, the smoke yield of HCN could be reduced up to 50%, indicating the great potential of these microspheres as absorbents for removing HCN from cigarette smoke. Full article

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2018

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20 pages, 2051 KiB

Open AccessReview

Synthesis and Properties of Gelatin Methacryloyl (GelMA) Hydrogels and Their Recent Applications in Load-Bearing Tissue

by Mingyue Sun, Xiaoting Sun, Ziyuan Wang, Shuyu Guo, Guangjiao Yu and Huazhe Yang

Polymers 2018, 10(11), 1290; https://doi.org/10.3390/polym10111290 - 21 Nov 2018

Cited by 257 | Viewed by 21052

Abstract

Photocrosslinked gelatin methacryloyl (GelMA) hydrogels have attracted great concern in the biomedical field because of their good biocompatibility and tunable physicochemical properties. Herein, different approaches to synthesize GelMA were introduced, especially, the typical method using UV light to crosslink the gelatin-methacrylic anhydride (MA) [...] Read more.

Photocrosslinked gelatin methacryloyl (GelMA) hydrogels have attracted great concern in the biomedical field because of their good biocompatibility and tunable physicochemical properties. Herein, different approaches to synthesize GelMA were introduced, especially, the typical method using UV light to crosslink the gelatin-methacrylic anhydride (MA) precursor was introduced in detail. In addition, the traditional and cutting-edge technologies to characterize the properties of GelMA hydrogels and GelMA prepolymer were also overviewed and compared. Furthermore, the applications of GelMA hydrogels in cell culture and tissue engineering especially in the load-bearing tissue (bone and cartilage) were summarized, followed by concluding remarks. Full article

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15 pages, 4442 KiB

Open AccessArticle

Bagasse Cellulose Grafted with an Amino-Terminated Hyperbranched Polymer for the Removal of Cr(VI) from Aqueous Solution

by Lu Xia, Zhonghang Huang, Lei Zhong, Fengwei Xie, Chak Yin Tang and Chi Pong Tsui

Polymers 2018, 10(8), 931; https://doi.org/10.3390/polym10080931 - 20 Aug 2018

Cited by 31 | Viewed by 4671

Abstract

A novel bio-adsorbent was fabricated via grafting an amino-terminated hyperbranched polymer (HBP-NH₂) onto bagasse cellulose. The morphology and microstructure of the HBP-NH₂-grafted bagasse cellulose (HBP-g-BC) were characterized and its adsorption capacity for Cr(VI) ions in aqueous solutions [...] Read more.

A novel bio-adsorbent was fabricated via grafting an amino-terminated hyperbranched polymer (HBP-NH₂) onto bagasse cellulose. The morphology and microstructure of the HBP-NH₂-grafted bagasse cellulose (HBP-g-BC) were characterized and its adsorption capacity for Cr(VI) ions in aqueous solutions was investigated. The rough surface structure of HBP-g-BC that is beneficial for improving the adsorption capacity was observed by scanning electron microscopy (SEM). The grafting reaction was confirmed by Fourier-transform infrared (FT-IR) spectroscopy. The adsorbent performance was shown to be better with a lower pH value, a higher adsorbent dosage, or a higher initial Cr(VI) concentration. Moreover, the kinetics study revealed that the adsorption behavior followed a pseudo-second-order model. The isotherm results showed that the adsorption data could be well-fitted by the Langmuir, Freundlich, or Temkin models. Moreover, HBP-g-BC could maintain 74.4% of the initial removal rate even after five cycles of regeneration. Thus, the high potential of HBP-g-BC as a bio-adsorbent for heavy metal removal has been demonstrated. Full article

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