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13 pages, 2817 KiB

Open AccessArticle

Structure–Elasticity Relationships in Hybrid-Carrageenan Hydrogels Studied by Image Dynamic Light Scattering, Ultra-Small-Angle Light Scattering and Dynamic Rheometry

by Amine Ben Yahia, Adel Aschi, Bruno Faria and Loic Hilliou

Materials 2024, 17(17), 4331; https://doi.org/10.3390/ma17174331 - 31 Aug 2024

Viewed by 640

Abstract

Hybrid-carrageenan hydrogels are characterized using novel techniques based on high-resolution speckle imaging, namely image dynamic light scattering (IDLS) and ultra-small-angle light scattering (USALS). These techniques, used to probe the microscopic structure of the system in sol–gel phase separation and at different concentrations in [...] Read more.

Hybrid-carrageenan hydrogels are characterized using novel techniques based on high-resolution speckle imaging, namely image dynamic light scattering (IDLS) and ultra-small-angle light scattering (USALS). These techniques, used to probe the microscopic structure of the system in sol–gel phase separation and at different concentrations in the gel phase, give access to a better understanding of the network’s topology on the basis of fractals in the dense phase. Observations of the architecture and the spatial and the size distributions of gel phase and fractal dimension were performed by USALS. The pair-distance distribution function, P(r), extracted from USALS patterns, is a new methodology of calculus for determining the network’s internal size with precision. All structural features are systematically compared with a linear and non-linear rheological characterization of the gels and structure–elasticity relationships are identified in the framework of fractal colloid gels in the diffusion limit. Full article

(This article belongs to the Special Issue Modification and Processing of Biodegradable Polymers (Volume II))

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17 pages, 4066 KiB

Open AccessArticle

Microwaved-Assisted Synthesis of Starch-Based Biopolymer Membranes for Novel Green Electrochemical Energy Storage Devices

by Paweł Jeżowski, Jakub Menzel, Hanna Maria Baranowska and Przemysław Łukasz Kowalczewski

Materials 2023, 16(22), 7111; https://doi.org/10.3390/ma16227111 - 10 Nov 2023

Cited by 4 | Viewed by 1165

Abstract

The investigated starch biopolymer membrane was found to be a sustainable alternative to currently reported and used separators due to its properties, which were evaluated using physicochemical characterization. The molecular dynamics of the biomembrane were analyzed using low-field nuclear magnetic resonance (LF NMR) [...] Read more.

The investigated starch biopolymer membrane was found to be a sustainable alternative to currently reported and used separators due to its properties, which were evaluated using physicochemical characterization. The molecular dynamics of the biomembrane were analyzed using low-field nuclear magnetic resonance (LF NMR) as well as Raman and infrared spectroscopy, which proved that the chemical composition of the obtained membrane did not degrade during microwave-assisted polymerization. Easily and cheaply prepared through microwave-assisted polymerization, the starch membrane was successfully used as a biodegradable membrane separating the positive and negative electrodes in electric double-layer capacitors (EDLCs). The obtained results for the electrochemical characterization via cyclic voltammetry (CV), galvanostatic charge with potential limitation (GCPL), and electrochemical impedance spectroscopy (EIS) show a capacitance of 30 F g⁻¹ and a resistance of 2 Ohms; moreover, the longevity of the EDLC during electrochemical floating exceeded more than 200 h or a cyclic ability of 50,000 cycles. Furthermore, due to the flexibility of the membrane, it can be easily used in novel, flexible energy storage systems. This proves that this novel biomembrane can be a significant step toward ecologically friendly energy storage devices and could be considered a cheaper alternative to currently used materials, which cannot easily biodegrade over time in comparison to biopolymers. Full article

(This article belongs to the Special Issue Modification and Processing of Biodegradable Polymers (Volume II))

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20 pages, 5915 KiB

Open AccessArticle

Preparation and Spectroscopic, Thermal, and Mechanical Characterization of Biocomposites of Poly(butylene succinate) and Onion Peels or Durum Wheat Bran

by Emil Sasimowski, Marta Grochowicz and Łukasz Szajnecki

Materials 2023, 16(20), 6799; https://doi.org/10.3390/ma16206799 - 21 Oct 2023

Cited by 1 | Viewed by 1458

Abstract

The utilization of plant based fillers: onion peels (OP) and durum wheat bran (WB) to obtain sustainable biocomposite materials with poly(butylene succinate) (PBS) is presented in this paper. The biocomposites were first obtained in pellet form by extrusion method and then injection moldings [...] Read more.

The utilization of plant based fillers: onion peels (OP) and durum wheat bran (WB) to obtain sustainable biocomposite materials with poly(butylene succinate) (PBS) is presented in this paper. The biocomposites were first obtained in pellet form by extrusion method and then injection moldings were made from the pellets. Two kinds of biocomposites were fabricated containing 15% and 30% wt. of OP or WB. Additionally, pure PBS moldings were prepared for comparative purposes. The effect of the filler type and its amount on the chemical structure, density, thermal, and thermo-mechanical properties of the fabricated composite samples was studied. Fourier-transform infrared spectroscopy results showed that the composite preparation method had no effect on the chemical structure of composite components, but weak interactions such as hydrogen bonding between OP or WB and PBS was observed. The addition of OP or WB to the composite with PBS reduced its thermal stability in comparison with pure PBS, all studied composites start to degrade below 290 °C. Additionally, the mechanical properties of the composites are worse than PBS, as the impact strength dropped by about 70%. The deterioration of tensile strength was in the range 20–47%, and the elongation at maximum load of the composites was in the range 9.22–3.42%, whereas for pure PBS it was 16.75%. On the other hand, the crystallinity degree increased from 63% for pure PBS to 79% for composite with 30% wt. of WB. The Young’s modulus increased to 160% for composition with 30% wt. of OP. Additionally, the hardness of the composites was slightly higher than PBS and was in the range 38.2–48.7 MPa. Despite the reduction in thermal stability and some mechanical properties, the studied composites show promise for everyday object production. Full article

(This article belongs to the Special Issue Modification and Processing of Biodegradable Polymers (Volume II))

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15 pages, 2889 KiB

Open AccessArticle

Effect of Polydopamine and Curcumin on Physicochemical and Mechanical Properties of Polymeric Blends

by Muhammad Tahir and Alina Sionkowska

Materials 2023, 16(17), 5758; https://doi.org/10.3390/ma16175758 - 23 Aug 2023

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Abstract

In this study, we prepared composites made from polyvinyl alcohol (PVA), sodium alginate (SA), curcumin (Cur), and polydopamine (PD). The film-forming properties of the composites were researched for potential wound-healing applications. The structures of the polymer blends and composites were studied by FTIR [...] Read more.

In this study, we prepared composites made from polyvinyl alcohol (PVA), sodium alginate (SA), curcumin (Cur), and polydopamine (PD). The film-forming properties of the composites were researched for potential wound-healing applications. The structures of the polymer blends and composites were studied by FTIR spectroscopy and microscopic observations (AFM and SEM). The mechanical properties were measured using a Zwick Roell testing machine. It was observed that the formation of a polymeric film based on the blend of polyvinyl alcohol and sodium alginate led to the generation of pores. The presence of curcumin in the composite resulted in the alteration of the blend properties. After solvent evaporation, the polymeric blend of PVA, SA, and curcumin formed a stable polymeric film, but the film showed poor mechanical properties. The addition of polydopamine led to an improvement in the mechanical strength of the film and an increase in its surface roughness. A polymeric film of sodium alginate presented the highest surface roughness value among all the studied specimens (66.6 nm), whereas polyvinyl alcohol showed the lowest value (1.60 nm). The roughness of the composites made of PVA/SA/Cur and PVA/SA/Cur/PD showed a value of about 25 nm. Sodium alginate showed the highest values of Young’s modulus (4.10 GPa), stress (32.73 N), and tensile strength (98.48 MPa). The addition of PD to PVA/SA/Cur led to an improvement in the mechanical properties. Improved mechanical properties and appropriate surface roughness may suggest that prepared blends can be used for the preparation of wound-healing materials. Full article

(This article belongs to the Special Issue Modification and Processing of Biodegradable Polymers (Volume II))

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12 pages, 6586 KiB

Open AccessArticle

Structural and Thermal Examinations of Polyamide Modified with Fly Ash from Biomass Combustion

by Renata Caban and Adam Gnatowski

Materials 2023, 16(15), 5277; https://doi.org/10.3390/ma16155277 - 27 Jul 2023

Cited by 3 | Viewed by 1133

Abstract

This paper presents the results of examinations of the structure and crystallinity of polyamide (PA6) modified with fly ash from biomass combustion in a fluidized-bed boiler. Composites based on a PA6 matrix were examined. They contained 5, 10, and 15 wt% fly ash. [...] Read more.

This paper presents the results of examinations of the structure and crystallinity of polyamide (PA6) modified with fly ash from biomass combustion in a fluidized-bed boiler. Composites based on a PA6 matrix were examined. They contained 5, 10, and 15 wt% fly ash. Fourier-transform infrared with attenuated total reflectance spectroscopy (FTIR-ATR) was used to identify the characteristic functional groups present in the chemical structure of polyamide and composites based on its matrix. Structural analysis was performed using a differential scanning calorimeter (DSC) and microscopic examinations. Analysis of the values of thermal effects determined using the DSC technique allowed for the evaluation of the degree of crystallinity of the materials studied. Polyamide is usually considered to be a two-phase system consisting of crystalline and amorphous regions. The addition of the filler in the form of fly ash reduced the degree of crystallinity of the studied specimens. Based on the FTIR-ATR spectra and the recorded DSC curves, it was found that the α-phase was the dominant crystalline phase in the studied materials. Microscopic examinations were conducted to analyze the microstructure of the materials, providing information on the distribution and shape of the filler particles. Most of the particles ranged in size from a few to tens of micrometers. Furthermore, the use of scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS) allowed for the analysis of the distribution of chemical elements in selected filler particles. Full article

(This article belongs to the Special Issue Modification and Processing of Biodegradable Polymers (Volume II))

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22 pages, 3830 KiB

Open AccessArticle

Modification of Polycaprolactone with Plant Extracts to Improve the Aging Resistance

by Krzysztof Moraczewski, Magdalena Stepczyńska, Rafał Malinowski, Tomasz Karasiewicz, Bartłomiej Jagodziński and Piotr Rytlewski

Materials 2023, 16(14), 5154; https://doi.org/10.3390/ma16145154 - 21 Jul 2023

Cited by 2 | Viewed by 897

Abstract

Natural extracts of plant origin are used as anti-aging compounds of biodegradable polymers. Coffee, cocoa, or cinnamon extracts in amounts from 0.5 to 10 wt.% were added to the polycaprolactone matrix. The manufactured materials were aged at elevated temperatures with increased relative humidity [...] Read more.

Natural extracts of plant origin are used as anti-aging compounds of biodegradable polymers. Coffee, cocoa, or cinnamon extracts in amounts from 0.5 to 10 wt.% were added to the polycaprolactone matrix. The manufactured materials were aged at elevated temperatures with increased relative humidity and continuous exposure to UV radiation for 720, 1440, or 2160 h. The performance of the proposed extracts was compared with the retail anti-aging compound, butylated hydroxytoluene. Visual assessment, FTIR analysis, melt flow rate, tensile strength, impact tensile strength, thermogravimetry, and differential scanning calorimetry tests were conducted. Results showed that the use of lower contents of the tested extracts is particularly advantageous. When the content of the extract did not exceed 1 wt.%, no unfavorable influence on the properties of the materials was observed. The stabilizing performance during accelerated aging was mostly similar to or greater than that of the reference compound used. Full article

(This article belongs to the Special Issue Modification and Processing of Biodegradable Polymers (Volume II))

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Review

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29 pages, 2450 KiB

Open AccessReview

Chitosan and Its Derivatives: Preparation and Antibacterial Properties

by Anton R. Egorov, Anatoly A. Kirichuk, Vasili V. Rubanik, Vasili V. Rubanik, Jr., Alexander G. Tskhovrebov and Andreii S. Kritchenkov

Materials 2023, 16(18), 6076; https://doi.org/10.3390/ma16186076 - 5 Sep 2023

Cited by 23 | Viewed by 3664

Abstract

This comprehensive review illuminates the various methods of chitosan extraction, its antibacterial properties, and its multifarious applications in diverse sectors. We delve into chemical, physical, biological, hybrid, and green extraction techniques, each of which presents unique advantages and disadvantages. The choice of method [...] Read more.

This comprehensive review illuminates the various methods of chitosan extraction, its antibacterial properties, and its multifarious applications in diverse sectors. We delve into chemical, physical, biological, hybrid, and green extraction techniques, each of which presents unique advantages and disadvantages. The choice of method is dictated by multiple variables, including the desired properties of chitosan, resource availability, cost, and environmental footprint. We explore the intricate relationship between chitosan’s antibacterial activity and its properties, such as cationic density, molecular weight, water solubility, and pH. Furthermore, we spotlight the burgeoning applications of chitosan-based materials like films, nanoparticles, nonwoven materials, and hydrogels across the food, biomedical, and agricultural sectors. The review concludes by highlighting the promising future of chitosan, underpinned by technological advancements and growing sustainability consciousness. However, the critical challenges of optimizing chitosan’s production for sustainability and efficiency remain to be tackled. Full article

(This article belongs to the Special Issue Modification and Processing of Biodegradable Polymers (Volume II))

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21 pages, 2957 KiB

Open AccessReview

From Seaweeds to Hydrogels: Recent Progress in Kappa-2 Carrageenans

by Hiléia K. S. Souza, Wala Kraiem, Amine Ben Yahia, Adel Aschi and Loïc Hilliou

Materials 2023, 16(15), 5387; https://doi.org/10.3390/ma16155387 - 31 Jul 2023

Cited by 6 | Viewed by 1835

Abstract

Hybrid carrageenans, also called kappa-2 (K2) or weak kappa, are a class of sulfated polysaccharides with thermo-reversible gelling properties in water and are extracted from a specific family of red seaweeds. K2 are known in the industry for their texturizing properties which are [...] Read more.

Hybrid carrageenans, also called kappa-2 (K2) or weak kappa, are a class of sulfated polysaccharides with thermo-reversible gelling properties in water and are extracted from a specific family of red seaweeds. K2 are known in the industry for their texturizing properties which are intermediate between those of kappa-carrageenans (K) and iota-carrageenans (I). As such, K2 are gaining industrial interest, as they can replace blends of K and I (K + I) in some niche applications. Over the last decade or so, some progress has been made in unravelling K2′s chemical structure. The understanding of K2 gel’s structure–rheological properties’ relationships has also improved. Such recent progress is reported here, reviewing the literature on gelling K2 published since the last review on the topic. The focus is on the seaweeds used for extracting K2, their block copolymer chemical structures, and how these impact on the gel’s formation and rheological properties. The outcome of this review is that additional rheological and structural studies of K2 hydrogels are needed, in particular to understand their viscoelastic behavior under large deformation and to unravel the differences between the texturizing properties of K2 and K + I. Full article

(This article belongs to the Special Issue Modification and Processing of Biodegradable Polymers (Volume II))

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