Polymers

Research

18 pages, 14281 KiB

Open AccessArticle

The Impact of Mechanical Recycling on Ligno-Cellulose Fibre Containing PLA Biocomposite

by Faizan Asad, Kirsi Immonen, Titta Kiiskinen, Atte Mikkelson and Essi Sarlin

Polymers 2025, 17(6), 732; https://doi.org/10.3390/polym17060732 - 11 Mar 2025

Viewed by 464

Biocomposites, made from biobased polymers with natural fibre reinforcement, offer a feasible path towards environment friendly and sustainable materials. However, biocomposites have struggled to attract ta market that is mostly dominated by conventional fossil-based polymers. To increase the cost efficiency and extend the [...] Read more.

Biocomposites, made from biobased polymers with natural fibre reinforcement, offer a feasible path towards environment friendly and sustainable materials. However, biocomposites have struggled to attract ta market that is mostly dominated by conventional fossil-based polymers. To increase the cost efficiency and extend the lifespan of biocomposites, the effects of mechanical recycling on their properties should be thoroughly explored. While there has been some research on recycling natural fibre-reinforced biocomposites, limited attention has been paid to biocomposites reinforced with softwood fibre. This study investigates the impact of mechanical recycling on poly-lactic acid (PLA) biocomposites reinforced with bleached and unbleached softwood kraft pulp fibres at 15 wt% and 30 wt%. The results show that single-stage mechanical recycling improves Young’s modulus by 11–13% while maintaining impact strength. Tensile strength remains stable for biocomposites with 15 wt% fibre but decreases by 6–8% for with 30 wt% biocomposites. Recycling improves fibre dispersion by reducing agglomeration but leads to PLA degradation, which could potentially be mitigated by adding virgin polymer or chain extenders. These findings highlight the potential for reusing PLA-softwood fibre biocomposites while emphasizing the need for further research into multiple recycling cycles. Full article

(This article belongs to the Special Issue Cellulose Fiber Polymer Composites)

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20 pages, 3960 KiB

Open AccessArticle

Sustainable All-Cellulose Biocomposites from Renewable Biomass Resources Fabricated in a Water-Based Processing System by the Vacuum-Filtration-Assisted Impregnation Method

by Özkan Yapar, Petteri Piltonen, Ajra Hadela and Aleksandra Lobnik

Polymers 2024, 16(13), 1921; https://doi.org/10.3390/polym16131921 - 5 Jul 2024

Viewed by 1597

Abstract

The increasing awareness of global ecological concerns and the rising sustainability consciousness associated with the manufacturing of non-renewable and non-biodegradable composite materials have led to extensive research on product and process developments of more sustainable, environmentally friendly, and fully biodegradable biocomposites for higher-value [...] Read more.

The increasing awareness of global ecological concerns and the rising sustainability consciousness associated with the manufacturing of non-renewable and non-biodegradable composite materials have led to extensive research on product and process developments of more sustainable, environmentally friendly, and fully biodegradable biocomposites for higher-value end-use applications. All-cellulose composites (ACCs) are an emerging class of biocomposites, which are produced utilizing solely cellulose as a raw material that is derived from various renewable biomass resources, such as trees and plants, and are assessed as fully biodegradable. In this study, sustainable ACCs were fabricated for the first time based on the full dissolution of commercially available sulfite dissolving (D) pulps as a matrix with concentrations of 1.5 wt.% and 2.0 wt.% in an aqueous NaOH–urea solvent, and they were then impregnated on/into the pre-fabricated birch (B), abaca (A), and northern softwood (N) fiber sheets as reinforcements by the vacuum-filtration-assisted impregnation approach. This research aimed to investigate the effects of the impregnated cellulose matrix concentrations and types of the utilized cellulose fiber reinforcements (B, A, N) on the morphological, crystalline, structural, and physio-mechanical properties of the ACCs. The highest degrees of improvements were achieved for tensile strength (+532%, i.e., from 9.24 MPa to 58.04 MPa) and strain at break of the B fiber-reinforced ACC B_1.5 (+446%, i.e., from 1.36% to 4.62%) fabricated with vacuum impregnation of the 1.5 wt.% cellulose matrix. Noticeably, the greatest improvements were attained in strain at break of the A and N fiber-reinforced ACCs A_2.0 (+218%, i.e., from 4.44 % to 14.11%) and N_2.0 (+466%, i.e., 2.59% to 14.65%), respectively, produced with vacuum impregnation of the 2.0 wt.% cellulose matrix. The study highlights the diverse properties of the all-cellulose biocomposite materials that could, expectedly, lead to further development and research for upscaled production of the ACCs. Full article

(This article belongs to the Special Issue Cellulose Fiber Polymer Composites)

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14 pages, 3963 KiB

Open AccessArticle

“Nano in Nano”—Incorporation of ZnO Nanoparticles into Cellulose Acetate–Poly(Ethylene Oxide) Composite Nanofibers Using Solution Blow Spinning

by Caroline Voorhis, Javier González-Benito and Ana Kramar

Polymers 2024, 16(3), 341; https://doi.org/10.3390/polym16030341 - 26 Jan 2024

Cited by 5 | Viewed by 2429

Abstract

In this work, the preparation and characterization of composites from cellulose acetate (CA)–poly(ethylene oxide) (PEO) nanofibers (NFs) with incorporated zinc oxide nanoparticles (ZnO-NPs) using solution blow spinning (SBS) is reported. CA–PEO nanofibers were produced by spinning solution that contained a higher CA-to-PEO ratio [...] Read more.

In this work, the preparation and characterization of composites from cellulose acetate (CA)–poly(ethylene oxide) (PEO) nanofibers (NFs) with incorporated zinc oxide nanoparticles (ZnO-NPs) using solution blow spinning (SBS) is reported. CA–PEO nanofibers were produced by spinning solution that contained a higher CA-to-PEO ratio and lower (equal) CA-to-PEO ratio. Nanoparticles were added to comprise 2.5% and 5% of the solution, calculated on the weight of the polymers. To have better control of the SBS processing conditions, characterization of the spinning suspensions is carried out, which reveals a decrease in viscosity (two- to eightfold) upon the addition of NPs. It is observed that this variation of viscosity does not significantly affect the mean diameters of nanofibers, but does affect the mode of the nanofibers’ size distribution, whereby lower viscosity provides thinner fibers. FESEM–EDS confirms ZnO NP encapsulation into nanofibers, specifically into the CA component based on UV-vis studies, since the release of ZnO is not detected for up to 5 days in deionized water, despite the significant swelling of the material and accompanied dissolution of water-soluble PEO. Upon the dissolution of CA nanofibers into acetone, immediate release of ZnO is detected, both visually and by spectrometer. ATR–FTIR studies reveal interaction of ZnO with the CA component of composite nanofibers. As ZnO nanoparticles are known for their bioactivity, it can be concluded that these CA–PEO–ZnO composites are good candidates to be used in filtration membranes, with no loss of incorporated ZnO NPs or their release into an environment. Full article

(This article belongs to the Special Issue Cellulose Fiber Polymer Composites)

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13 pages, 2680 KiB

Open AccessArticle

The Durable Chitosan Functionalization of Cellulosic Fabrics

by Sandra Flinčec Grgac, Tea-Dora Biruš, Anita Tarbuk, Tihana Dekanić and Ana Palčić

Polymers 2023, 15(18), 3829; https://doi.org/10.3390/polym15183829 - 20 Sep 2023

Cited by 4 | Viewed by 1755

Abstract

In this work, the durability of chitosan functionalization of cellulosic textile substrates, cotton and cotton/polyester blended fabrics, was studied. Chitosan is a naturally occurring biopolymer that can be produced inexpensively. It should be dissolved in an acidic solution to activate its antimicrobial and [...] Read more.

In this work, the durability of chitosan functionalization of cellulosic textile substrates, cotton and cotton/polyester blended fabrics, was studied. Chitosan is a naturally occurring biopolymer that can be produced inexpensively. It should be dissolved in an acidic solution to activate its antimicrobial and other properties, i.e., good biocompatibility, bioabsorbability, wound healing, hemostatic, anti-infective, antibacterial, non-toxic, and adsorptive properties. The application of chitosan to textile products has been researched to achieve antimicrobial properties, but the durability, after several maintenance cycles, has not. Chitosan functionalization was carried out using maleic acid (MA) and 1,2,3,4-butanetetracarboxylic acid (BTCA) as crosslinking and chitosan-activating agents and sodium hypophosphite monohydrate as a catalyst. To determine durability, the fabrics were subjected to 10 maintenance cycles according to ISO 6330:2012 using Reference detergent 3 and drying according to Procedure F. The properties were monitored after the 3rd and 10th cycles. The crosslinking ability of chitosan with cellulosic fabrics was monitored by Fourier infrared spectrometry using the ATR technique (FTIR-ATR). Changes in mechanical properties, whiteness and yellowing, and antimicrobial properties were determined using standard methods. Compared to maleic acid, BTCA proved to be a better crosslinking agent for chitosan. Full article

(This article belongs to the Special Issue Cellulose Fiber Polymer Composites)

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26 pages, 7242 KiB

Open AccessArticle

Emission and Mechanical Properties of Glass and Cellulose Fiber Reinforced Bio-Polyamide Composites

by Susanne Wolff, Annette Rüppel, Hassan Ali Rida and Hans-Peter Heim

Polymers 2023, 15(12), 2603; https://doi.org/10.3390/polym15122603 - 7 Jun 2023

Cited by 8 | Viewed by 2404

Abstract

Climate change, access, and monopolies to raw material sources as well as politically motivated trade barriers are among the factors responsible for a shortage of raw materials. In the plastics industry, resource conservation can be achieved by substituting commercially available petrochemical-based plastics with [...] Read more.

Climate change, access, and monopolies to raw material sources as well as politically motivated trade barriers are among the factors responsible for a shortage of raw materials. In the plastics industry, resource conservation can be achieved by substituting commercially available petrochemical-based plastics with components made from renewable raw materials. Innovation potentials are often not used due to a lack of information on the use of bio-based materials, efficient processing methods, and product technologies or because the costs for new developments are too high. In this context, the use of renewable resources such as fiber-reinforced polymeric composites based on plants has become an important criterion for the development and production of components and products in all industrial sectors. Bio-based engineering thermoplastics with cellulose fibers can be used as substitutes because of their higher strength and heat resistance, but the processing of this composite is still challenging. In this study, composites were prepared and investigated using bio-based polyamide (PA) as a polymer matrix in combination with a cellulosic fiber and, for comparison purposes, a glass fiber. A co-rotating twin-screw extruder was used to produce the composites with different fiber contents. For the mechanical properties, tensile tests and charpy impact tests were performed. Compared to glass fiber, reinforced PA 6.10 and PA 10.10, a significantly higher elongation at break with regenerated cellulose fibers, can be achieved. PA 6.10 and PA 10.10 achieve significantly higher impact strengths with the regenerated cellulose fibers than the composites with glass fibers. In the future, bio-based products will also be used in indoor applications. For characterization, the VOC emission GC-MS analysis and odor evaluation methods were used. The VOC emissions (quantitative) were at a low level but the results of the odor tests of selected samples showed values mostly above the required limit values. Full article

(This article belongs to the Special Issue Cellulose Fiber Polymer Composites)

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15 pages, 6912 KiB

Open AccessArticle

Macro-Size Regenerated Cellulose Fibre Embedded with Graphene Oxide with Antibacterial Properties

by Nyak Syazwani Nyak Mazlan, Kushairi Mohd Salleh, Mohamad Khalid Khairunnisa-Atiqah, Abdul Hair Ainul Hafiza, Marhaini Mostapha, Amanda V. Ellis and Sarani Zakaria

Polymers 2023, 15(1), 230; https://doi.org/10.3390/polym15010230 - 1 Jan 2023

Cited by 4 | Viewed by 2603

Abstract

Macro-size regenerated cellulose fibres (RCFs) with embedded graphene oxide (GO) were fabricated by dissolving cellulose in a pre-cooled sodium hydroxide (NaOH)/urea solution and regenerated in sulphuric acid (H₂SO₄) coagulant. Initially, GO was found to disperse well in the cellulose [...] Read more.

Macro-size regenerated cellulose fibres (RCFs) with embedded graphene oxide (GO) were fabricated by dissolving cellulose in a pre-cooled sodium hydroxide (NaOH)/urea solution and regenerated in sulphuric acid (H₂SO₄) coagulant. Initially, GO was found to disperse well in the cellulose solution due to intercalation with the cellulose; however, this cellulose–GO intercalation was disturbed during the regeneration process, causing agglomeration of GO in the RCF mixture. Agglomerated GO was confirmed at a higher GO content under a Dino-Lite microscope. The crystallinity index (CrI) and thermal properties of the RCFs increased with increasing GO loadings, up to 2 wt.%, and reduced thereafter. Cellulose–GO intercalation was observed at lower GO concentrations, which enhanced the crystallinity and thermal properties of the RCF–GO composite. It was shown that the GO exhibited antibacterial properties in the RCF–GO composite, with the highest bacterial inhibition against E. coli and S. aureus. Full article

(This article belongs to the Special Issue Cellulose Fiber Polymer Composites)

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15 pages, 4124 KiB

Open AccessArticle

Enhancement of Antimicrobial and Dyeing Properties of Cellulosic Fabrics via Chitosan Nanoparticles

by Rehab M. Mosaad, Mona H. Alhalafi, El-Amir M. Emam, Marwan A. Ibrahim and Hassan Ibrahim

Polymers 2022, 14(19), 4211; https://doi.org/10.3390/polym14194211 - 7 Oct 2022

Cited by 24 | Viewed by 2758

Abstract

The primary goal of this study is to prepare chitosan nanoparticles (CSNPs) by the ionic gelation method via the treatment of chitosan (0.2 wt.%) with tripolyphosphate (0.2 wt.%) ultrasonically for 45 min. FT-IR spectroscopy and TEM images were used to characterize and validate [...] Read more.

The primary goal of this study is to prepare chitosan nanoparticles (CSNPs) by the ionic gelation method via the treatment of chitosan (0.2 wt.%) with tripolyphosphate (0.2 wt.%) ultrasonically for 45 min. FT-IR spectroscopy and TEM images were used to characterize and validate CSNP production. Cellulosic materials with different concentrations of CSNPs have better antibacterial and colouring characteristics. The treated cellulosic fabrics were analyzed by FT-IR spectroscopy, SEM, and thermogravimetric analysis. Colourimetric data measurements expressed in K/S values were used to evaluate the impact of CSNPs on the dyeing affinity of cellulosic materials. In addition, antibacterial activity against bacteria and fungi was tested on the treated cellulosic fabrics. According to the K/S values, cellulosic textiles treated with CSNPs (0.3 wt.%) had a better affinity for acid dyeing. These textiles also offer better antibacterial properties and are more resistant to washing, light, and rubbing. A cytotoxicity study found that CSNPs give cellulosic materials antibacterial and acid dyeing properties, which is good for the environment. Full article

(This article belongs to the Special Issue Cellulose Fiber Polymer Composites)

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17 pages, 4841 KiB

Open AccessArticle

All-Cellulose Composite Laminates Made from Wood-Based Textiles: Effects of Process Conditions and the Addition of TEMPO-Oxidized Nanocellulose

by Eija-Katriina Uusi-Tarkka, Jaka Levanič, Henrik Heräjärvi, Nawar Kadi, Mikael Skrifvars and Antti Haapala

Polymers 2022, 14(19), 3959; https://doi.org/10.3390/polym14193959 - 22 Sep 2022

Cited by 10 | Viewed by 2926

Abstract

All-cellulose composites (ACCs) are manufactured using only cellulose as a raw material. Biobased materials are more sustainable alternatives to the petroleum-based composites that are used in many technical and life-science applications. In this study, an aquatic NaOH-urea solvent system was used to produce [...] Read more.

All-cellulose composites (ACCs) are manufactured using only cellulose as a raw material. Biobased materials are more sustainable alternatives to the petroleum-based composites that are used in many technical and life-science applications. In this study, an aquatic NaOH-urea solvent system was used to produce sustainable ACCs from wood-based woven textiles with and without the addition of TEMPO-oxidized nanocellulose (at 1 wt.-%). This study investigated the effects of dissolution time, temperature during hot press, and the addition of TEMPO-oxidized nanocellulose on the mechanical and thermal properties of the composites. The results showed a significant change in the tensile properties of the layered textile composite at dissolution times of 30 s and 1 min, while ACC elongation was the highest after 2 and 5 min. Changes in hot press temperature from 70 °C to 150 °C had a significant effect: with an increase in hot press temperature, the tensile strength increased and the elongation at break decreased. Incorporating TEMPO-oxidized nanocellulose into the interface of textile layers before partial dissolution improved tensile strength and, even more markedly, the elongation at break. According to thermal analyses, textile-based ACCs have a higher storage modulus (0.6 GPa) and thermal stabilization than ACCs with nanocellulose additives. This study highlights the important roles of process conditions and raw material characteristics on the structure and properties of ACCs. Full article

(This article belongs to the Special Issue Cellulose Fiber Polymer Composites)

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13 pages, 4196 KiB

Open AccessArticle

Application of Lignin-Containing Cellulose Nanofibers and Cottonseed Protein Isolate for Improved Performance of Paper

by Jacobs H. Jordan, Michael W. Easson, Huai N. Cheng and Brian D. Condon

Polymers 2022, 14(11), 2154; https://doi.org/10.3390/polym14112154 - 25 May 2022

Cited by 3 | Viewed by 2436

Abstract

There is current interest in replacing petroleum-based additives in consumer paper products with abundantly available, renewable and sustainable biopolymers such as lignin-containing cellulose nanofibers (LCNFs) and cottonseed protein. This research characterized the performance of cottonseed protein isolate with/without LCNFs to increase the dry [...] Read more.

There is current interest in replacing petroleum-based additives in consumer paper products with abundantly available, renewable and sustainable biopolymers such as lignin-containing cellulose nanofibers (LCNFs) and cottonseed protein. This research characterized the performance of cottonseed protein isolate with/without LCNFs to increase the dry strength of filter paper. The application of 10% protein solution with 2% LCNFs as an additive improved the elongation at break, tensile strength and modulus of treated paper products compared to the improved performance of cottonseed protein alone. Improvements in tensile modulus and tensile strength were greatest for samples containing larger amounts of lignin and a greater degree of polymerization than for those with less lignin from the same biomass sources. Full article

(This article belongs to the Special Issue Cellulose Fiber Polymer Composites)

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