Research

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17 pages, 3470 KiB

Open AccessArticle

A Green Treatment Mitigates the Limitations of Coffee Silver Skin as a Filler for PLA/PBSA Compatibilized Biocomposites

by Davide Perin, Andrea Dorigato, Erica Bertoldi, Luca Fambri and Giulia Fredi

Molecules 2024, 29(1), 226; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules29010226 - 31 Dec 2023

Viewed by 798

The development of fully renewable and biodegradable composites for short-term applications was pursued by combining a compatibilized poly(lactic acid) (PLA)/poly(butylene succinate-co-adipate) (PBSA) (60:40 wt:wt) blend with coffee silver skin (CSS), an industrial byproduct from coffee processing. An epoxy-based reactive agent (Joncryl ADR-4468) was [...] Read more.

The development of fully renewable and biodegradable composites for short-term applications was pursued by combining a compatibilized poly(lactic acid) (PLA)/poly(butylene succinate-co-adipate) (PBSA) (60:40 wt:wt) blend with coffee silver skin (CSS), an industrial byproduct from coffee processing. An epoxy-based reactive agent (Joncryl ADR-4468) was added as a compatibilizer. CSS was incorporated at 5, 10, and 20 wt% in the blend both in the as-received state and after a simple thermal treatment in boiling water, which was performed to mitigate the negative impact of this filler on the rheological and mechanical properties of the blend. The CSS treatment effectively increased the filler degradation temperature of 30–40 °C, enabling stable melt processing of the composites. It also improved filler–matrix adhesion, resulting in enhanced impact properties (up to +172% increase in impact energy compared to the untreated filler). Therefore, treated CSS demonstrated potential as an effective green reinforcement for PLA/PBSA blends for rigid packaging applications. Future works will focus on studying suitable surface modification of CSS to further increase the interfacial interaction and the tensile quasi-static properties, to fully exploit the capabilities of this renewable material toward the development of eco-friendly composites. Full article

(This article belongs to the Special Issue New Functional Materials Based on Natural Polymers Obtained from Renewable Resources)

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9 pages, 2994 KiB

Open AccessCommunication

High-Value Oil–Water Separation Materials Prepared from Waste Polyethylene Terephthalate

by Changjian Zhou, Jiahao Zhang, Yuqing Fu, Maowan Wu, Heng Zhang, Qingle Shi, Yong Dai and He Zhao

Molecules 2023, 28(22), 7503; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules28227503 - 09 Nov 2023

Viewed by 623

Abstract

As one of the most common forms of waste, waste PET is a serious pollutant in natural and human living environments. There is an urgent need to recycle PET. For this study, the complete degradation of PET was realized at a low temperature. [...] Read more.

As one of the most common forms of waste, waste PET is a serious pollutant in natural and human living environments. There is an urgent need to recycle PET. For this study, the complete degradation of PET was realized at a low temperature. A lipophilic hydrophobic membrane was formed on the surface of a stainless steel mesh (SSM) using a simple dip coating method, and an oil–water separation material was successfully prepared. After loading with degradation products, the surface roughness of SSM increased from 19.09 μm to 62.33 μm. The surface changed from hydrophilic to hydrophobic, and the water contact angle increased to 123°. The oil–water separation flux of the modified SSM was 9825 L/(m²·h), and the separation efficiency was 98.99%. The modified SSM had good reuse performance. This hydrophobic modification method can also be used to modify other porous substrates, such as activated carbon, filter paper, foam, and other materials. The porous substrate modified by the degradation product of waste PET was used to prepare oil–water separation materials, not only solving the problem of white pollution but also reducing the dependence on non-renewable resources in the conventional methods used for the preparation of oil–water separation materials. This study provides new raw materials and methods for the industrial production of oil–water separation materials, which have important application prospects. Full article

(This article belongs to the Special Issue New Functional Materials Based on Natural Polymers Obtained from Renewable Resources)

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14 pages, 2324 KiB

Open AccessArticle

Smart Biopolymer-Based Nanocomposite Materials Containing pH-Sensing Colorimetric Indicators for Food Freshness Monitoring

by Milad Tavassoli, Mahmood Alizadeh Sani, Arezou Khezerlou, Ali Ehsani, Gholamreza Jahed-Khaniki and David Julian McClements

Molecules 2022, 27(10), 3168; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27103168 - 16 May 2022

Cited by 26 | Viewed by 3197

Abstract

Nanocomposite biopolymer materials containing colorimetric pH-responsive indicators were prepared from gelatin and chitosan nanofibers. Plant-based extracts from barberry and saffron, which both contained anthocyanins, were used as pH indicators. Incorporation of the anthocyanins into the biopolymer films increased their mechanical, water-barrier, and light-screening [...] Read more.

Nanocomposite biopolymer materials containing colorimetric pH-responsive indicators were prepared from gelatin and chitosan nanofibers. Plant-based extracts from barberry and saffron, which both contained anthocyanins, were used as pH indicators. Incorporation of the anthocyanins into the biopolymer films increased their mechanical, water-barrier, and light-screening properties. Infrared spectroscopy and scanning electron microscopy analysis indicated that a uniform biopolymer matrix was formed, with the anthocyanins distributed evenly throughout them. The anthocyanins in the composite films changed color in response to alterations in pH or ammonia gas levels, which was used to monitor changes in the freshness of packaged fish during storage. The anthocyanins also exhibited antioxidant and antimicrobial activity, which meant that they could also be used to slow down the degradation of the fish. Thus, natural anthocyanins could be used as both freshness indicators and preservatives in biopolymer-based nanocomposite packaging materials. These novel materials may therefore be useful alternatives to synthetic plastics for some food packaging applications, thereby improving the environmental friendliness and sustainability of the food supply. Full article

(This article belongs to the Special Issue New Functional Materials Based on Natural Polymers Obtained from Renewable Resources)

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13 pages, 1623 KiB

Open AccessArticle

Effect of Fatty Acid Polyunsaturation on Synthesis and Properties of Emulsion Polymers Based on Plant Oil-Based Acrylic Monomers

by Vasylyna Kirianchuk, Zoriana Demchuk, Yehor Polunin, Ananiy Kohut, Stanislav Voronov and Andriy Voronov

Molecules 2022, 27(3), 932; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27030932 - 29 Jan 2022

Viewed by 1547

Abstract

This study demonstrated that polymerization behavior of plant oil-based acrylic monomers (POBMs) synthesized in one-step transesterification reaction from naturally rich in oleic acid olive, canola, and high-oleic soybean oils is associated with a varying mass fraction of polyunsaturated fatty acid fragments (linoleic (C18:2) [...] Read more.

This study demonstrated that polymerization behavior of plant oil-based acrylic monomers (POBMs) synthesized in one-step transesterification reaction from naturally rich in oleic acid olive, canola, and high-oleic soybean oils is associated with a varying mass fraction of polyunsaturated fatty acid fragments (linoleic (C18:2) and linolenic (C18:3) acid esters) in plant oil. Using miniemulsion polymerization, a range of stable copolymer latexes was synthesized from 60 wt.% of each POBM and styrene to determine the impact of POBM chemical composition (polyunsaturation) on thermal and mechanical properties of the resulted polymeric materials. The unique composition of each plant oil serves as an experimental tool to determine the effect of polyunsaturated fatty acid fragments on POBM polymerization behavior and thermomechanical properties of crosslinked films made from POBM-based latexes. The obtained results show that increasing polyunsaturation in the copolymers results in an enhanced crosslink density of the latex polymer network which essentially impacts the mechanical properties of the films (both Young’s modulus and toughness). Maximum toughness was observed for crosslinked latex films made from 50 wt.% of each POBM in the monomer feed. Full article

(This article belongs to the Special Issue New Functional Materials Based on Natural Polymers Obtained from Renewable Resources)

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10 pages, 1487 KiB

Open AccessArticle

Characterisation of Hyaluronic Acid Blends Modified by Poly(N-Vinylpyrrolidone)

by Katarzyna Lewandowska and Marta Szulc

Molecules 2021, 26(17), 5233; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26175233 - 29 Aug 2021

Cited by 3 | Viewed by 1883

Abstract

The viscosity behaviour and physical properties of blends containing hyaluronic acid (HA) and poly(N-vinylpyrrolidone) (PVP) were studied by the viscometric technique, steady shear tests, tensile tests and infrared spectroscopy. Viscometric and rheological measurements were carried out using blends of HA/PVP with [...] Read more.

The viscosity behaviour and physical properties of blends containing hyaluronic acid (HA) and poly(N-vinylpyrrolidone) (PVP) were studied by the viscometric technique, steady shear tests, tensile tests and infrared spectroscopy. Viscometric and rheological measurements were carried out using blends of HA/PVP with different HA weight fractions (0, 0.2, 0.5, 0.8 and 1). The polymer films and HA/PVP blend films were prepared using the solution casting method. The study of HA blends by viscometry showed that HA/PVP was miscible with the exception of the blend with high HA content. HA and its blends showed a shear-thinning flow behaviour. The non-Newtonian indices (n) of HA/PVP blends were calculated by the Ostwald–de Waele equation, indicating a shear-thinning effect in which pseudoplasticity increased with increasing HA contents. Mechanical properties, such as tensile strength and elongation at the break, were higher for HA/PVP films with w_HA = 0.5 compared to those with higher HA contents. The elongation at the break of HA/PVP blend films displayed a pronounced increase compared to HA films. Moreover, infrared analysis confirmed the existence of interactions between HA and PVP. The blending of HA with PVP generated films with elasticity and better properties than homopolymer films. Full article

(This article belongs to the Special Issue New Functional Materials Based on Natural Polymers Obtained from Renewable Resources)

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20 pages, 9268 KiB

Open AccessFeature PaperArticle

Valorization of Byproducts of Hemp Multipurpose Crop: Short Non-Aligned Bast Fibers as a Source of Nanocellulose

by Sara Dalle Vacche, Vijayaletchumy Karunakaran, Alessia Patrucco, Marina Zoccola, Loreleï Douard, Silvia Ronchetti, Marta Gallo, Aigoul Schreier, Yves Leterrier, Julien Bras, Davide Beneventi and Roberta Bongiovanni

Molecules 2021, 26(16), 4723; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26164723 - 04 Aug 2021

Cited by 9 | Viewed by 2408

Abstract

Nanocellulose was extracted from short bast fibers, from hemp (Cannabis sativa L.) plants harvested at seed maturity, non-retted, and mechanically decorticated in a defibering apparatus, giving non-aligned fibers. A chemical pretreatment with NaOH and HCl allowed the removal of most of the [...] Read more.

Nanocellulose was extracted from short bast fibers, from hemp (Cannabis sativa L.) plants harvested at seed maturity, non-retted, and mechanically decorticated in a defibering apparatus, giving non-aligned fibers. A chemical pretreatment with NaOH and HCl allowed the removal of most of the non-cellulosic components of the fibers. No bleaching was performed. The chemically pretreated fibers were then refined in a beater and treated with a cellulase enzyme, followed by mechanical defibrillation in an ultrafine friction grinder. The fibers were characterized by microscopy, infrared spectroscopy, thermogravimetric analysis and X-ray diffraction after each step of the process to understand the evolution of their morphology and composition. The obtained nanocellulose suspension was composed of short nanofibrils with widths of 5–12 nm, stacks of nanofibrils with widths of 20–200 nm, and some larger fibers. The crystallinity index was found to increase from 74% for the raw fibers to 80% for the nanocellulose. The nanocellulose retained a yellowish color, indicating the presence of some residual lignin. The properties of the nanopaper prepared with the hemp nanocellulose were similar to those of nanopapers prepared with wood pulp-derived rod-like nanofibrils. Full article

(This article belongs to the Special Issue New Functional Materials Based on Natural Polymers Obtained from Renewable Resources)

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12 pages, 2128 KiB

Open AccessFeature PaperArticle

The Infuence of Salicin on Rheological and Film-Forming Properties of Collagen

by Katarzyna Adamiak, Katarzyna Lewandowska and Alina Sionkowska

Molecules 2021, 26(6), 1661; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26061661 - 16 Mar 2021

Cited by 13 | Viewed by 2442

Abstract

Collagen films are widely used as adhesives in medicine and cosmetology. However, its properties require modification. In this work, the influence of salicin on the properties of collagen solution and films was studied. Collagen was extracted from silver carp skin. The rheological properties [...] Read more.

Collagen films are widely used as adhesives in medicine and cosmetology. However, its properties require modification. In this work, the influence of salicin on the properties of collagen solution and films was studied. Collagen was extracted from silver carp skin. The rheological properties of collagen solutions with and without salicin were characterized by steady shear tests. Thin collagen films were prepared by solvent evaporation. The structure of films was researched using infrared spectroscopy. The surface properties of films were investigated using Atomic Force Microscopy (AFM). Mechanical properties were measured as well. It was found that the addition of salicin modified the roughness of collagen films and their mechanical and rheological properties. The above-mentioned parameters are very important in potential applications of collagen films containing salicin. Full article

(This article belongs to the Special Issue New Functional Materials Based on Natural Polymers Obtained from Renewable Resources)

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Review

Jump to: Research

19 pages, 6328 KiB

Open AccessReview

Poly(silyl ether)s as Degradable and Sustainable Materials: Synthesis and Applications

by Vladimir Zotov, Srikanth Vijjamarri, Seyed-Danial Mousavi and Guodong Du

Molecules 2024, 29(7), 1498; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules29071498 - 27 Mar 2024

Viewed by 584

Abstract

Polymer research is currently focused on sustainable and degradable polymers which are cheap, easy to synthesize, and environmentally friendly. Silicon-based polymers are thermally stable and can be utilized in various applications, such as columns and coatings. Poly(silyl ether)s (PSEs) are an interesting class [...] Read more.

Polymer research is currently focused on sustainable and degradable polymers which are cheap, easy to synthesize, and environmentally friendly. Silicon-based polymers are thermally stable and can be utilized in various applications, such as columns and coatings. Poly(silyl ether)s (PSEs) are an interesting class of silicon-based polymers that are easily hydrolyzed in either acidic or basic conditions due to the presence of the silyl ether Si-O-C bond. Synthetically, these polymers can be formed in several different ways, and the most effective and environmentally friendly synthesis is dehydrogenative cross coupling, where the byproduct is H₂ gas. These polymers have a lot of promise in the polymeric materials field due to their sustainability, thermal stability, hydrolytic degradability, and ease of synthesis, with nontoxic byproducts. In this review, we will summarize the synthetic approaches for the PSEs in the recent literature, followed by the properties and applications of these materials. A conclusion and perspective will be provided at the end. Full article

(This article belongs to the Special Issue New Functional Materials Based on Natural Polymers Obtained from Renewable Resources)

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