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15 pages, 1885 KiB

Open AccessArticle

Insight into the Mechanism for the Emergence of Thermally Stable Reflection Colors from Cholesteric Liquid Crystals of Etherified Ethyl Cellulose Derivatives and Methacrylic Acid

by Wakako Kishi, Naoto Iwata and Seiichi Furumi

Molecules 2025, 30(13), 2839; https://doi.org/10.3390/molecules30132839 - 2 Jul 2025

Abstract

Ethyl cellulose (EC) and its derivatives are known to exhibit the cholesteric liquid crystal (CLC) phase with visible light reflection in a lyotropic manner after adding appropriate solvents. Generally, the reflection peak of conventional CLCs is easily wavelength shifted by temperature. However, our [...] Read more.

Ethyl cellulose (EC) and its derivatives are known to exhibit the cholesteric liquid crystal (CLC) phase with visible light reflection in a lyotropic manner after adding appropriate solvents. Generally, the reflection peak of conventional CLCs is easily wavelength shifted by temperature. However, our previous study showed that the reflection wavelength can be maintained even after heating for the lyotropic CLCs of completely pentyl-etherified EC derivatives with methacrylic acid (MAA). However, the emergence of thermally stable reflection colors still remains obscure in the mechanism at the mesoscopic scale. In this study, we evaluated the temperature dependence of the reflection wavelength for the lyotropic CLCs of a series of completely etherified EC derivatives possessing different alkoxy chains by addition of MAA. It was found that butyl- or pentyl-etherified EC derivatives are suitable for preparation of the lyotropic CLCs with visible Bragg reflection, whereas visible light reflection cannot be observed for the other mixtures of propyl- and hexyl-etherified EC derivatives with MAA. Furthermore, it turned out that lyotropic CLCs of pentyl-etherified EC derivatives with MAA show the smallest temperature dependence of their reflection wavelength. Based on the results of ultra-small-angle X-ray scattering (USAXS) and small-angle X-ray scattering (SAXS) measurements of CLC films, we presumed that the emergence of thermally stable reflection colors from the lyotropic CLCs of pentyl-etherified EC derivatives with MAA arises from their phase separation at the mesoscopic scale by changing the temperature. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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25 pages, 2691 KiB

Open AccessArticle

Bioplastic Production Using Natural Extracts with Cellulose Assisted by Experimental and Computational Screening

by Lizbeth Zamora-Mendoza, Jhonny Caicho, José R. Mora, Daniela Negrete-Bolagay, Victor H. Guerrero, Noroska G. S. Mogollón, Melanie Ochoa-Ocampo, Jefferson Pastuña-Fasso, José F. Álvarez Barreto, Sebastián Ponce, Juan Paredes, Henry Erazo, Patricia I. Pontón, Marco León and Frank Alexis

Molecules 2025, 30(13), 2752; https://doi.org/10.3390/molecules30132752 - 26 Jun 2025

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Abstract

The increasing demand for sustainable and environmentally friendly materials has prompted intensive research into developing bioplastics as viable alternatives to conventional petroleum-derived plastics. Here, we report a novel approach to bioplastic production by employing plant extract-based solvents to partially dissolve cellulose, a fundamental [...] Read more.

The increasing demand for sustainable and environmentally friendly materials has prompted intensive research into developing bioplastics as viable alternatives to conventional petroleum-derived plastics. Here, we report a novel approach to bioplastic production by employing plant extract-based solvents to partially dissolve cellulose, a fundamental biopolymer precursor. Using plant-derived solvents addresses concerns surrounding the environmental impact of traditional solvent-based processes, as per the principles of green chemistry. Using computational screening, some natural products were identified from the integrated database resource MEGx. Six natural sources were selected based on their molecular weight, high pKa, and chemical classification. Thin-layer chromatography (TLC) and column chromatography confirmed the presence of molecules in the extracts. Bioplastics were prepared with 1, 3, 6, 10, and 15 wt.% plant extract concentrations. Control samples without conventional dissolved and positive controls were also studied to compare their properties with novel bioplastics. Chemical characterization and biodegradability tests were performed. Degradation in water and soil tests for 35 days showed that the biodegradability of the bioplastics with natural extracts at higher concentrations was faster than that of the control samples. By day 35, bioplastics containing 15 wt.% of the D1 W extract showed rapid degradation, with higher weight loss compared with the conventional controls. The positive control (C4), containing NaOH and glycerol, degraded more slowly than the plant extract-based formulations. Also, the test indicated that the natural dissolvent’s influence on the water uptake of the material produced a better performance than the control samples. The surfaces of the bioplastic formulations were analyzed using a scanning electron microscope (SEM) at different magnifications. The findings presented here hold promise for advancing the field of bioplastics and contributing to the sustainable utilization of plant resources for eco-friendly material production. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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15 pages, 1315 KiB

Open AccessArticle

Functionalisation of Lignin-Derived Diols for the Synthesis of Thermoplastic Polyurethanes and Polyester Resins

by Rachele N. Carafa, Justin J. S. Kosalka, Brigida V. Fernandes, Unnati Desai, Daniel A. Foucher and Guerino G. Sacripante

Molecules 2025, 30(12), 2604; https://doi.org/10.3390/molecules30122604 - 16 Jun 2025

Viewed by 256

Abstract

The functionalisation of lignin-derived phenolics (guaiacol, 4-propylguaiacol, eugenol, isoeugenol, phenol, m-cresol, catechol, syringol, syringaldehyde, and vanillin) for the synthesis of thermoplastic polyurethanes (PUs) and polyester (PE) resins is herein described. Diols were synthesised from phenolics in a one-step reaction using either glycerol [...] Read more.

The functionalisation of lignin-derived phenolics (guaiacol, 4-propylguaiacol, eugenol, isoeugenol, phenol, m-cresol, catechol, syringol, syringaldehyde, and vanillin) for the synthesis of thermoplastic polyurethanes (PUs) and polyester (PE) resins is herein described. Diols were synthesised from phenolics in a one-step reaction using either glycerol carbonate or ethylene carbonate as a greener, solvent-free synthetic route. Nine of the diols were selected for the synthesis of Pus, and two of the diols were used for the synthesis of PE resins, with their physical and thermal properties characterised. Analysis of the PUs by differential scanning calorimetry (DSC) confirmed their amorphous nature, while thermogravimetric analysis (TGA) suggested improved thermal stability for all PUs with the addition of an alkyl or aldehyde substituent on the benzene ring regardless of the diisocyanate used. However, lower PU thermal stabilities were observed with the use of an aliphatic diisocyanate over an aromatic diisocyanate in the absence of an additional substituent. Analysis of the PEs by DSC also confirmed that the clear resins were all amorphous, and gel permeation chromatography (GPC) revealed significantly higher molecular weights and dispersities when an aliphatic diacid was utilised over an aromatic diacid. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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18 pages, 2627 KiB

Open AccessArticle

NaOH/Urea-Compatible Chitosan/Carboxymethylcellulose Films: Orthogonal Optimization of Packaging Properties

by Chang Yu, Hui Sun, Lin Yao and Yunxuan Weng

Molecules 2025, 30(11), 2279; https://doi.org/10.3390/molecules30112279 - 22 May 2025

Viewed by 423

Abstract

Chitosan (CS)-based films have demonstrated significant potential as biodegradable packaging materials, but their suboptimal barrier and mechanical properties limit practical applications. In this study, CS/carboxymethyl cellulose (CMC) composite films were prepared using a NaOH/urea-based alkaline system. Optimal ratios (1.5% CS, 2% CMC, 2.5% [...] Read more.

Chitosan (CS)-based films have demonstrated significant potential as biodegradable packaging materials, but their suboptimal barrier and mechanical properties limit practical applications. In this study, CS/carboxymethyl cellulose (CMC) composite films were prepared using a NaOH/urea-based alkaline system. Optimal ratios (1.5% CS, 2% CMC, 2.5% NaOH, and 4% urea) were determined through an L₁₆(4⁴) orthogonal array design. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses confirmed the formation of stable physical crosslinks between CS and CMC via hydrogen bonding. These interactions significantly enhanced mechanical properties (tensile strength: 46.08 MPa; elongation at break: 68%), improved thermal stability (maximum decomposition temperature: 304 °C), and superior barrier properties (water vapor transmission rate: 0.26 × 10⁻⁵ g/(m²·h·Pa); oxygen transmission rate: 1.12 × 10⁻⁴ g/(m²·s)). NaOH concentration exhibited the most pronounced influence on film performance. The composite film combines inherent biodegradability with excellent functional properties, offering a sustainable alternative to conventional petroleum-based packaging materials. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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24 pages, 4064 KiB

Open AccessArticle

Active Pectin/Carboxymethylcellulose Composite Films for Bread Packaging

by Lavinia Doveri, Yuri Antonio Diaz Fernandez, Giacomo Dacarro, Pietro Grisoli, Chiara Milanese, Maria Urena, Nicolas Sok, Thomas Karbowiak and Piersandro Pallavicini

Molecules 2025, 30(11), 2257; https://doi.org/10.3390/molecules30112257 - 22 May 2025

Viewed by 426

Abstract

A new active composite film intended for bread packaging is described here. The active film has the aim of prolonging bread’s shelf life while avoiding the use of nanoparticles that, with very few exceptions, are a type of material not allowed by regulatory [...] Read more.

A new active composite film intended for bread packaging is described here. The active film has the aim of prolonging bread’s shelf life while avoiding the use of nanoparticles that, with very few exceptions, are a type of material not allowed by regulatory agencies like EFSA (European Food Safety Agency) and FDA (US Food and Drug Administration) in food contact materials. Moreover, the increasing consumer demand for natural and wholesome products, possibly “clean label”, and packaged in natural, non-petroleum-based materials has been taken into consideration. Accordingly, precursor materials from renewable sources were used to prepare the active film: pectin from citrus peel (PEC) and carboxymethyl cellulose (CMC) were used as the matrix, with oleic acid (OA) as plasticizer. Moreover, the bread preservative calcium propionate (CaP) was used as the crosslinker, and also zeolite microparticles loaded with silver ions (AgZ) were added to the films as an additional antimold agent. This strategy allows us to avoid the addition to bread of the now commonly used preservatives ethanol and calcium propionate, moving the latter to the packaging. Permeance measurements revealed excellent barrier properties against O₂ and CO₂, while the typical high water vapor permeance of polysaccharide films was mitigated by the non-hydrophilic OA plasticizer. Moreover, the quantities of Ag⁺ and CaP released in bread are low and below the limits imposed by regulatory agencies. The antimold activity of the films is excellent, with Aspergillus niger, Penicillium janthinellum, and wild-type Penicillim molds reduction on bread in the 99.20–99.95% range for the films containing only CaP and in the 99.97–99.998% range for the films containing both CaP and AgZ. Finally, the rheological properties of the film-forming solutions were investigated, demonstrating their potential application as coatings on natural packaging materials for bread, such as paper. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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17 pages, 1390 KiB

Open AccessArticle

Laser-Powered Homogeneous Pyrolysis (LPHP) of Lignin Dispersed into Gas Phase

by Mohamad Barekati-Goudarzi, Lavrent Khachatryan, Rubik Asatryan, Dorin Boldor and Bert C. Lynn

Molecules 2025, 30(10), 2215; https://doi.org/10.3390/molecules30102215 - 19 May 2025

Viewed by 283

Abstract

The gas-phase delivery of lignin into the hot zone of cw-CO₂ laser-powered homogeneous pyrolysis (LPHP) reactor under “wall-less” conditions led to the breakdown of lignin macromolecules into neutral oligomers and paramagnetic fragments deposited onto the reactor cell walls. The formation of PAHs [...] Read more.

The gas-phase delivery of lignin into the hot zone of cw-CO₂ laser-powered homogeneous pyrolysis (LPHP) reactor under “wall-less” conditions led to the breakdown of lignin macromolecules into neutral oligomers and paramagnetic fragments deposited onto the reactor cell walls. The formation of PAHs was observed during the defragmentation of lignin, accelerated with increased laser power. Remarkably, no phenolic compounds were detected among lignin fragments—intermediate radicals and neutral oligomers. It is concluded that the PAH and soot-like conjugated particulates are formed in the hot zone of the LPHP reactor, resembling the high-temperature combustion processes. The key role of the resonantly stabilized radicals in the formation of low-molecular-weight PAHs is outlined. An alternative pathway is proposed for the generation of PAH involving the formation of cyclopentadienyl radical precursors (CPDa) that are adsorbed onto or trapped within lignin macromolecules. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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13 pages, 10341 KiB

Open AccessArticle

Preparation and Modification of Sucrose-Based Non-Isocyanate Polyurethane Adhesives for Plywood Bonding

by Hongyi Zhong, Qianyu Zhang, Hong Lei, Xiaojian Zhou, Jun Zhang, Guanben Du, Antonio Pizzi and Xuedong Xi

Molecules 2025, 30(7), 1541; https://doi.org/10.3390/molecules30071541 - 30 Mar 2025

Viewed by 459

Abstract

The production of non-isocyanate polyurethane (NIPU) resins using recyclable biomass materials and no isocyanates as a substitute for traditional polyurethane (PU) materials has become a research focus in the polyurethane industry. The development of such NIPU resins for application as wood adhesives has [...] Read more.

The production of non-isocyanate polyurethane (NIPU) resins using recyclable biomass materials and no isocyanates as a substitute for traditional polyurethane (PU) materials has become a research focus in the polyurethane industry. The development of such NIPU resins for application as wood adhesives has also emerged as an interesting new research topic. In this study, sucrose was used to react with dimethyl carbonate, and then polymerized with an amine to prepare sucrose-based non-isocyanate polyurethane (SNIPU) adhesives and evaluate their suitability for use in plywood. Four amines, namely polyethylene amine (PEI) of molecular weight (MW) 10,000, PEI of MW 1800, diethylenetriamine, and hexanediamine were tested in the preparation of SNIPU adhesives to determine a more suitable amine showing optimal adhesion performance. The effect of the amount of the amine added on adhesive properties was further investigated. The results showed that the SNIPU adhesive prepared with PEI-10000 as amine presents a good bonding performance. The SNIPU prepared with a PEI-10000 content of 45% (w/w on sucrose) presented the highest bonding strength. The dry strength, 24 h cold water (23 °C) wet strength, and 3 h hot water (63 °C and 93 °C) wet strengths of its bonded plywood were 1.26 MPa, 0.90 MPa, 0.84 MPa, and 0.80 MPa, respectively. Furthermore, the addition of 13% (w/w on SNIPU adhesive) of ethylene glycol diglycidyl ether (EGDE) as a modifier showed a significant decrease of 20 °C of the curing temperature of the SNIPU adhesive. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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14 pages, 3801 KiB

Open AccessArticle

Hydrochar from Agricultural Waste as a Biobased Support Matrix Enhances the Bacterial Degradation of Diethyl Phthalate

by Emanuel Gheorghita Armanu, Simone Bertoldi, Matthias Schmidt, Hermann J. Heipieper, Irina Volf and Christian Eberlein

Molecules 2025, 30(5), 1167; https://doi.org/10.3390/molecules30051167 - 5 Mar 2025

Cited by 1 | Viewed by 3794

Abstract

The hydrothermal carbonization (HTC) of biomass presents a sustainable approach for waste management and production of value-added materials such as hydrochar, which holds promise as an adsorbent and support matrix for bacterial immobilization applied, e.g., for bioremediation processes of sites contaminated with phthalate [...] Read more.

The hydrothermal carbonization (HTC) of biomass presents a sustainable approach for waste management and production of value-added materials such as hydrochar, which holds promise as an adsorbent and support matrix for bacterial immobilization applied, e.g., for bioremediation processes of sites contaminated with phthalate ester plasticizers such as diethyl phthalate (DEP). In the present study, hydrochar was synthesized from vine shoots (VSs) biomass employing the following parameters during the HTC process: 260 °C for 30 min with a 1:10 (w/v) biomass-to-water ratio. The resulting vine shoots hydrochar (VSs-HC) was characterized for porosity, elemental composition, and structural properties using Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), and Raman spectroscopy. Elemental analysis confirmed the presence of key elements in the VSs structure, elements essential for char formation during the HTC process. The VSs-HC exhibited a macroporous structure (>0.5 μm), facilitating diethyl phthalate (DEP) adsorption, bacterial adhesion, and biofilm formation. Adsorption studies showed that the VSs-HC achieved a 90% removal rate for 4 mM DEP within the first hour of contact. Furthermore, VS-HC was tested as a support matrix for a bacterial consortium (Pseudomonas spp. and Microbacterium sp.) known to degrade DEP. The immobilized bacterial consortium on VSs-HC demonstrated enhanced tolerance to DEP toxicity, degrading 76% of 8 mM DEP within 24 h, compared with 14% by planktonic cultures. This study highlights VSs-HC’s potential as a sustainable and cost-effective material for environmental bioremediation, offering enhanced bacterial cell viability, improved biofilm formation, and efficient plasticizer removal. These findings provide a pathway for mitigating environmental pollution through scalable and low-cost solutions. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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14 pages, 8824 KiB

Open AccessArticle

Thermoplastic Phenomena and Morphological Changes upon Fast Pyrolysis of Biomass and Model Compounds

by Francesca Cerciello, Christophe Allouis, Carmela Russo, Erik Freisewinkel, David Tarlinski, Barbara Apicella, Martin Schiemann, Viktor Scherer and Osvalda Senneca

Molecules 2025, 30(3), 700; https://doi.org/10.3390/molecules30030700 - 5 Feb 2025

Viewed by 668

Abstract

The work reports preliminary results on the morphological changes that biomass particles experience at high heating rates in a heated strip reactor (HSR) at T = 1000–1600 °C under an inert atmosphere. Samples included a natural lignocellulosic biomass (pinewood) as well as biomass [...] Read more.

The work reports preliminary results on the morphological changes that biomass particles experience at high heating rates in a heated strip reactor (HSR) at T = 1000–1600 °C under an inert atmosphere. Samples included a natural lignocellulosic biomass (pinewood) as well as biomass components: cellulose, hemicellulose (xylan) and lignin. On top of that, reference compounds have been investigated, namely naphthalene pitch, a paraffinic wax and glucose. During the heat-up phase, the investigated biomass mainly retains the original morphology and size, while the single components exhibit different behaviors. Hemicellulose undergoes a fluid stage and eventually forms millimetric spherical char particles. Cellulose does not become fully fluid but softens and forms millimetric char aggregates of different shapes. Lignin particles hardly soften and stick together in a curved slab. Comparison with model compounds allows us to infer that the degree of melting and the viscosity of the melt are responsible for the final particle shape. In fact, naphthalene pitch and glucose appear to be more viscous during pyrolysis and lead to the formation of three-dimensional columns a few millimeters high. Wax undergoes extensive melting, but the relatively low viscosity and the absence of crosslinking reactions eventually lead only to the formation of droplets. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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13 pages, 4048 KiB

Open AccessArticle

Facile Preparation Route of Cellulose-Based Flame Retardant by Ball-Milling Mechanochemistry

by Mohamed Aaddouz, Fouad Laoutid, Jerome Mariage, Jevgenij Lazko, Bopha Yada, El Miloud Mejdoubi, Antoniya Toncheva and Philippe Dubois

Molecules 2024, 29(24), 6065; https://doi.org/10.3390/molecules29246065 - 23 Dec 2024

Viewed by 979

Abstract

In this study, a sustainable cellulose-based flame-retardant additive was developed, characterized, and incorporated into polypropylene (PP). Microcrystalline cellulose (Cel) was chemically modified with P₂O₅ using the solvent-free ball-milling mechanochemistry approach at room temperature. This modification enabled phosphorus grafting onto cellulose, [...] Read more.

In this study, a sustainable cellulose-based flame-retardant additive was developed, characterized, and incorporated into polypropylene (PP). Microcrystalline cellulose (Cel) was chemically modified with P₂O₅ using the solvent-free ball-milling mechanochemistry approach at room temperature. This modification enabled phosphorus grafting onto cellulose, significantly enhancing the cellulose charring ability and improving the thermal stability of the char as revealed by thermogravimetric analysis (TGA). The resulting product, Cel-P, containing 4.15 wt.% phosphorus, was incorporated and uniformly dispersed as a flame-retardant (FR) additive at 30 wt.% in PP through melt processing. The PP+30-Cel-P composite demonstrated improved char formation and FR properties, including reduction of both peak heat release rate (pHRR) and total heat release (THR) in mass loss cone calorimetry (MLC). Moreover, lower light absorptivity was obtained by smoke opacity tests as compared to PP filled with unmodified cellulose. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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Review

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75 pages, 15988 KiB

Open AccessReview

Tailoring Polymer Properties Through Lignin Addition: A Recent Perspective on Lignin-Derived Polymer Modifications

by Nawoda L. Kapuge Dona and Rhett C. Smith

Molecules 2025, 30(11), 2455; https://doi.org/10.3390/molecules30112455 - 3 Jun 2025

Viewed by 471

Abstract

Lignin, an abundant and renewable biopolymer, has gained significant attention as a sustainable modifier and building block in polymeric materials. Recent advancements highlight its potential to tailor mechanical, thermal, and barrier properties of polymers while offering a greener alternative to petroleum-based additives. This [...] Read more.

Lignin, an abundant and renewable biopolymer, has gained significant attention as a sustainable modifier and building block in polymeric materials. Recent advancements highlight its potential to tailor mechanical, thermal, and barrier properties of polymers while offering a greener alternative to petroleum-based additives. This review provides an updated perspective on the incorporation of lignin into various polymer matrices, focusing on lignin modification techniques, structure–property relationships, and emerging applications. Special emphasis is given to recent innovations in lignin functionalization and its role in developing high-performance, biodegradable, and recyclable materials such as polyurethanes, epoxy resins, phenol-formaldehyde resins, lignin-modified composites, and lignin-based films, coatings, elastomers, and adhesives. These lignin-based materials are gaining attention for potential applications in construction, automated industries, packaging, textiles, wastewater treatment, footwear, supporting goods, automobiles, printing rollers, sealants, and binders. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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15 pages, 1760 KiB

Open AccessReview

Transparent Wood Fabrication and Applications: A Review

by Le Van Hai, Narayanan Srikanth, Tin Diep Trung Le, Seung Hyeon Park and Tae Hyun Kim

Molecules 2025, 30(7), 1506; https://doi.org/10.3390/molecules30071506 - 28 Mar 2025

Viewed by 1708

Abstract

Wood cellulose is an abundant bio-based resource with diverse applications in construction, cosmetics, packaging, and the pulp and paper industries. Transparent wood (TW) is a novel, high-quality wood material with several advantages over traditional transparent materials (e.g., glass and plastic). These benefits include [...] Read more.

Wood cellulose is an abundant bio-based resource with diverse applications in construction, cosmetics, packaging, and the pulp and paper industries. Transparent wood (TW) is a novel, high-quality wood material with several advantages over traditional transparent materials (e.g., glass and plastic). These benefits include renewability, UV shielding, lightweight properties, low thermal expansion, reduced glare, and improved mechanical strength. TW has significant potential for various applications, including transparent roofs, windows, home lighting structures, electronic devices, home decoration, solar cells, packaging, smart packaging materials, and other high-value-added products. The mechanical properties of TW, such as tensile strength and optical transmittance, are typically up to 500 MPa (Young’s modulus of 50 GPa) and 10–90%, respectively. Fabrication methods, wood types, and processing conditions significantly influence the mechanical and optical properties of TW. In addition, recent research has highlighted the feasibility of TW and large-scale production, making it an emerging research topic for future exploration. This review attempted to provide recent and updated manufacturing methods of TW as well as current and future applications. In particular, the effects of structural modification through various chemical pretreatment methods and impregnation methods using various polymers on the properties of TW biocomposites were also reviewed. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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15 pages, 4421 KiB

Open AccessReview

Unusual Lignocellulosic Bioresins: Adhesives and Coatings for Metals and Glass

by Antonio Pizzi

Molecules 2024, 29(22), 5401; https://doi.org/10.3390/molecules29225401 - 15 Nov 2024

Viewed by 1387

Abstract

This minireview presents some unusual but encouraging examples of lignocellulosic-based adhesives and coatings used for metals, glass, and some other difficult-to-adhere materials. The reactions and applications presented are as follows. (i) The reactions of tannins and wood lignin with phosphate salts, in particular [...] Read more.

This minireview presents some unusual but encouraging examples of lignocellulosic-based adhesives and coatings used for metals, glass, and some other difficult-to-adhere materials. The reactions and applications presented are as follows. (i) The reactions of tannins and wood lignin with phosphate salts, in particular triethylphosphate, to adhere and join steel and aluminum to Teflon, in particular for non-stick frying pans. These adhesive coatings have been shown to sustain the relevant factory industrial test of 410 °C for 11 min and, moreover, to present a 50% material loss even at 900 °C for 5 min. (ii) Non-isocyanate polyurethanes (NIPU) based on glucose and sucrose as coatings of steel and glass. These were obtained by the carbonation of carbohydrates through reaction with the inexpensive dimethyl carbonate followed by reaction with a diamine; all materials used were bio-sourced. Lastly, (iii) the use of citric acid-based adhesive coupled with any hydroxyl groups carrying material for coating metals is also described. These three approaches give a clear indication of the possibilities and capabilities of biomaterials in this field. All these are presented and discussed. Full article

(This article belongs to the Special Issue Advances in Polymer Materials Based on Lignocellulosic Biomass)

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