Polymers

Research

Jump to: Review

17 pages, 3034 KiB

Open AccessArticle

Developing a Biodegradable Film for Packaging with Lignocellulosic Materials from the Amazonian Biodiversity

by Danillo Wisky Silva, Felipe Gomes Batista, Mário Vanoli Scatolino, Adriano Reis Prazeres Mascarenhas, Dayane Targino De Medeiros, Gustavo Henrique Denzin Tonoli, Daniel Alberto Álvarez Lazo, Francisco de Tarso Ribeiro Caselli, Tiago Marcolino de Souza and Francisco Tarcísio Alves Junior

Polymers 2023, 15(17), 3646; https://doi.org/10.3390/polym15173646 - 4 Sep 2023

Cited by 4 | Viewed by 1958

Abstract

The development of packaging films made from renewable raw materials, which cause low environmental impact, has gained attention due to their attractive properties, which have become an exciting option for synthetic films. In this study, cellulose micro/nanofibrils (MFC/NFC) films were produced with forest [...] Read more.

The development of packaging films made from renewable raw materials, which cause low environmental impact, has gained attention due to their attractive properties, which have become an exciting option for synthetic films. In this study, cellulose micro/nanofibrils (MFC/NFC) films were produced with forest residues from the Amazon region and evaluated for their potential to generate alternative packaging to traditional plastic packaging. The MFC/NFC were obtained by mechanical fibrillation from fibers of açaí seeds (Euterpe oleracea), titica vine (Heteropsis flexuosa), and commercial pulps of Eucalyptus sp. for comparison. The fibrillation of the titica vine culminated in higher energy expenditure on raw materials. The açaí films showed a higher tensile strength (97.2 MPa) compared to the titica films (46.2 MPa), which also showed a higher permeability rate (637.3 g day⁻¹ m⁻²). Films of all raw materials scored the highest in the grease resistance test (n° 12). The films produced in the study showed potential for use in packaging for light and low moisture products due to their adequate physical, mechanical, and barrier characteristics. New types of pre-treatments or fibrillation methods ecologically correct and viable for reducing energy consumption must be developed, mainly for a greater success of titica vine fibrillation at the nanoscale. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Graphical abstract

12 pages, 2017 KiB

Open AccessArticle

Effects of Heat Treatment under Different Pressures on the Properties of Bamboo

by Dan Li, Shoulu Yang, Zhu Liu, Zhongwei Wang, Ning Ji and Jialei Liu

Polymers 2023, 15(14), 3074; https://doi.org/10.3390/polym15143074 - 18 Jul 2023

Cited by 6 | Viewed by 1612

Abstract

To optimize the bamboo heat treatment process, the corresponding evolution rules under various heat treatment conditions must be determined. When the heat treatment time and temperature remained constant, the effects of different heat treatment pressures on the equilibrium moisture content, dimensional stability, mechanical [...] Read more.

To optimize the bamboo heat treatment process, the corresponding evolution rules under various heat treatment conditions must be determined. When the heat treatment time and temperature remained constant, the effects of different heat treatment pressures on the equilibrium moisture content, dimensional stability, mechanical properties, and chemical composition of bamboo were systematically investigated. In this experiment, bamboo without heat treatment was used as the control group. The experimental findings demonstrate the following: (1) The equilibrium moisture content of heat-treated bamboo gradually decreases with increasing treatment pressure. When the heat treatment pressure was set at 0.1, 0.15, 0.2, and 0.25 MPa, the bamboo’s equilibrium water content decreased to 12.1%, 11.7%, 9.9%, and 8.6%, respectively, while that of the control group was 13.8%. (2) The dimensional stability of bamboo was enhanced with increasing heat treatment pressure. At pressures of 0.1, 0.15, 0.2, and 0.25 MPa, the radial air-dry shrinkage rates of the heat-treated bamboo decreased to 3.4%, 3.4%, 2.6%, and 2.3%, respectively, while the tangential air-dry shrinkage rates reduced to 5.6%, 5.1%, 3.3%, and 3.0%. In comparison, the radial and tangential air-dry shrinkage rates of the control group were measured as 3.6% and 5.8%, respectively. Similarly, the radial and tangential full-dry shrinkage of bamboo exhibited a similar trend. (3) With the increase in heat treatment pressure, the bending strength and longitudinal compressive strength of bamboo exhibited an initial rise followed by a decline. When it was at heat treatment pressures of 0.1, 0.15, 0.2, and 0.25 MPa, the corresponding bending strengths of the heat-treated bamboo were measured as 41.2, 26.7, 22.4, and 20.4 MPa, respectively; while the longitudinal compressive strengths were recorded as 42.6, 38.1, 29.1, and 25.3 MPa. In comparison, the bending and longitudinal compressive strengths of the control group were measured as 39.8 and 38.5 MPa, respectively. It is evident that the optimal heat treatment pressure for bamboo is 0.1 MPa, resulting in a significant increase of 3.5% and 10.6% in bending strength and longitudinal compressive strength, respectively, compared to the control group. (4) Based on the FTIR and XRD patterns of bamboo samples, a range of physical and chemical transformations were observed during the heat treatment process, including cellulose adsorb water evaporation, hemicellulose and cellulose degradation, as well as acetyl group hydrolysis on the molecular chain of hemicellulose. These changes collectively impacted the physical and mechanical properties of bamboo. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

10 pages, 1598 KiB

Open AccessArticle

Covalent Crosslinking Cellulose/Graphene Aerogels with High Elasticity and Adsorbability for Heavy Metal Ions Adsorption

by Peipei Sun, Meng Wang, Tingting Wu, Longsuo Guo and Wenjia Han

Polymers 2023, 15(11), 2434; https://doi.org/10.3390/polym15112434 - 24 May 2023

Cited by 13 | Viewed by 2097

Abstract

With the fast development of modern industry, heavy metal contaminant became more severe. How to remove heavy metal ions in water in a green and efficient way is a prominent problem in current environmental protection. The adsorption of cellulose aerogel as a novel [...] Read more.

With the fast development of modern industry, heavy metal contaminant became more severe. How to remove heavy metal ions in water in a green and efficient way is a prominent problem in current environmental protection. The adsorption of cellulose aerogel as a novel heavy metal removal technology has many advantages, including abundant resources, environmental friendly, high specific surface, high porosities and without second pollution, which means it has a wide application prospect. Here, we reported a self-assembly and covalent crosslinking strategy to prepare elastic and porous cellulose aerogels using PVA and graphene and cellulose as precursor. The resulting cellulose aerogel had a low density of 12.31 mg cm⁻³ and excellent mechanical properties, which can recover to its initial form at 80% compressive strain. Meanwhile, the cellulose aerogel had strong adsorption capacity of Cu²⁺ (80.12 mg g⁻¹), C_d²⁺ (102.23 mg g⁻¹), Cr³⁺ (123.02 mg g⁻¹), Co²⁺ (62.38 mg g⁻¹), Zn²⁺ (69.55 mg g⁻¹), and Pb²⁺ (57.16 mg g⁻¹). In addition, the adsorption mechanism of the cellulose aerogel was investigated using adsorption kinetics and adsorption isotherm, and the conclusion was that the adsorption process was mainly controlled by chemisorption mechanism. Therefore, cellulose aerogel, as a kind of green adsorption material, has a very high application potential in future water treatment applications. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

14 pages, 3905 KiB

Open AccessArticle

Impact- and Thermal-Resistant Epoxy Resin Toughened with Acacia Honey

by Ivana Stajcic, Filip Veljkovic, Milos Petrovic, Suzana Veličkovic, Vesna Radojevic, Branislav Vlahović and Aleksandar Stajcic

Polymers 2023, 15(10), 2261; https://doi.org/10.3390/polym15102261 - 10 May 2023

Cited by 4 | Viewed by 1978

Abstract

High performance polymers with bio-based modifiers are promising materials in terms of applications and environmental impact. In this work, raw acacia honey was used as a bio-modifier for epoxy resin, as a rich source of functional groups. The addition of honey resulted in [...] Read more.

High performance polymers with bio-based modifiers are promising materials in terms of applications and environmental impact. In this work, raw acacia honey was used as a bio-modifier for epoxy resin, as a rich source of functional groups. The addition of honey resulted in the formation of highly stable structures that were observed in scanning electron microscopy images as separate phases at the fracture surface, which were involved in the toughening of the resin. Structural changes were investigated, revealing the formation of a new aldehyde carbonyl group. Thermal analysis confirmed the formation of products that were stable up to 600 °C, with a glass transition temperature of 228 °C. An energy-controlled impact test was performed to compare the absorbed impact energy of bio-modified epoxy containing different amounts of honey with unmodified epoxy resin. The results showed that bio-modified epoxy resin with 3 wt% of acacia honey could withstand several impacts with full recovery, while unmodified epoxy resin broke at first impact. The absorbed energy at first impact was 2.5 times higher for bio-modified epoxy resin than it was for unmodified epoxy resin. In this manner, by using simple preparation and a raw material that is abundant in nature, a novel epoxy with high thermal and impact resistance was obtained, opening a path for further research in this field. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

12 pages, 3281 KiB

Open AccessArticle

Modification Mechanisms and Properties of Poplar Wood via Grafting with 2-Hydroxyethyl Methacrylate/N,N′-methylenebis(acrylamide) onto Cell Walls

by Jihang Hu and Xiaoqing Wang

Polymers 2023, 15(8), 1861; https://doi.org/10.3390/polym15081861 - 13 Apr 2023

Cited by 4 | Viewed by 1680

Abstract

As the only renewable resource among the four basic materials (steel, cement, plastic, wood), wood itself and wood products have a “low carbon” value and play an important role in storing carbon. The moisture absorption and expansion properties of wood limit its application [...] Read more.

As the only renewable resource among the four basic materials (steel, cement, plastic, wood), wood itself and wood products have a “low carbon” value and play an important role in storing carbon. The moisture absorption and expansion properties of wood limit its application scope and shorten its service life. To enhance the mechanical and physical properties of fast-growing poplars, an eco-friendly modification procedure has been used. This was accomplished by the in situ modification of wood cell walls by vacuum pressure impregnation with a reaction of water-soluble 2-hydroxyethyl methacrylate (HEMA) and N,N’-methylenebis(acrylamide) (MBA). The anti-swelling efficiency of HEMA/MBA-treated wood was improved (up to 61.13%), whereas HEMA/MBA-treated wood presented a lower weight-gain rate (WG) and water-absorption rate (WAR). It was observed that the modulus of elasticity, hardness, density, and other properties of modified wood had improved significantly, as indicated by XRD analysis. Modifiers diffuse primarily within cell walls and cell interstices of wood, causing crosslinks between the modifiers and the cell walls, reducing its hydroxyl content and blocking the channels for water movement, thereby enhancing its physical properties. This result can be obtained by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX), Nitrogen adsorption test imaging ATR-FTIR (Attenuated total reflection-Fourier-Transform Infrared) Spectroscopy, and nuclear magnetic resonance (NMR) and Nitrogen adsorption test. Overall, this straightforward, high-performance modification method is crucial for maximizing wood’s efficiency and the sustainable development of human society. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

13 pages, 2718 KiB

Open AccessArticle

Preparation and Properties Study of Wood-Based Cushioning Materials

by Shuang Pei, Zongying Fu, Jinsheng Gou and Yun Lu

Polymers 2023, 15(6), 1417; https://doi.org/10.3390/polym15061417 - 13 Mar 2023

Cited by 1 | Viewed by 2164

Abstract

Traditional cushioning package materials, such as Expended Polystyrene (EPS) and Expanded Polyethylene (EPE), were made with petroleum-based plastics, which are harmful to the environment. It is crucial to develop renewable bio-based cushioning materials that can replace the aforementioned foams due to the rising [...] Read more.

Traditional cushioning package materials, such as Expended Polystyrene (EPS) and Expanded Polyethylene (EPE), were made with petroleum-based plastics, which are harmful to the environment. It is crucial to develop renewable bio-based cushioning materials that can replace the aforementioned foams due to the rising energy demands of human society and the depletion of fossil fuels. Herein, we report an effective strategy for creating anisotropic elastic wood with special spring-like lamellar structures. Selective removal of lignin and hemicellulose by simple chemical treatment and thermal treatment of the samples after freeze-drying results in an elastic material with good mechanical properties. The resulting elastic wood has a reversible compression rate of 60% and a high elastic recovery (99% height retention after 100 cycles at 60% strain). Drop tests revealed that the elastic wood has excellent cushioning properties. In addition, the chemical and thermal treatments also enlarge the pores in the material, which is favorable for subsequent functionalization. By loading the elastic wood with a muti-walled carbon nanotube (MWCNT), electromagnetic shielding properties are achieved, while the mechanical properties of elastic wood remain unchanged. Electromagnetic shielding materials can effectively suppress various electromagnetic waves propagating through space and the resulting electromagnetic interference and electromagnetic radiation, improve the electromagnetic compatibility of electronic systems and electronic equipment, and ensure the safety of information. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Graphical abstract

16 pages, 2721 KiB

Open AccessArticle

Supramolecular Optimization of Sensory Function of a Hemicurcuminoid through Its Incorporation into Phospholipid and Polymeric Polydiacetylenic Vesicles: Experimental and Computational Insight

by Bulat S. Akhmadeev, Olga O. Retyunskaya, Sergey N. Podyachev, Sergey A. Katsyuba, Aidar T. Gubaidullin, Svetlana N. Sudakova, Victor V. Syakaev, Vasily M. Babaev, Oleg G. Sinyashin and Asiya R. Mustafina

Polymers 2023, 15(3), 714; https://doi.org/10.3390/polym15030714 - 31 Jan 2023

Cited by 1 | Viewed by 1728

Abstract

This work presents the synthesis of a new representative of hemicurcuminoids with a nonyloxy substituent (HCur) as a fluorescent amphiphilic structural element of vesicular aggregates based on phosphatidylcholine (PC), phosphatidylserine (PS), and 10,12-pentacosadiynoic acid (PCDA). Both X-ray diffraction analysis of the [...] Read more.

This work presents the synthesis of a new representative of hemicurcuminoids with a nonyloxy substituent (HCur) as a fluorescent amphiphilic structural element of vesicular aggregates based on phosphatidylcholine (PC), phosphatidylserine (PS), and 10,12-pentacosadiynoic acid (PCDA). Both X-ray diffraction analysis of the single crystal and ¹H NMR spectra of HCur in organic solvents indicate the predominance of the enol-tautomer of HCur. DFT calculations show the predominance of the enol tautomer HCur in supramolecular assemblies with PC, PS, and PCDA molecules. The results of the molecular modeling show that HCur molecules are surrounded by PC and PS with a rather weak exposure to water molecules, while an exposure of HCur molecules to water is enhanced under its supramolecular assembly with PCDA molecules. This is in good agreement with the higher loading of HCur into PC(PS) vesicles compared to PCDA vesicles converted into polydiacetylene (PDA) ones by photopolymerization. HCur molecules incorporated into HCur-PDA vesicles exhibit greater planarity distortion and hydration effect in comparison with HCur-PC(PS) ones. HCur-PDA is presented as a dual fluorescence-chromatic nanosensor responsive to a change in pH within 7.5–9.5, heavy metal ions and polylysine, and the concentration-dependent fluorescent response is more sensitive than the chromatic one. Thus, the fluorescent response of HCur-PDA allows for the distinguishing between Cd²⁺ and Pb²⁺ ions in the concentration range 0–0.01 mM, while the chromatic response allows for the selective sensing of Pb²⁺ over Cd²⁺ ions at their concentrations above 0.03 mM. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Graphical abstract

11 pages, 2537 KiB

Open AccessArticle

pH-Responsive Carbon Foams with Switchable Wettability Made from Larch Sawdust for Oil Recovery

by Jia Tan, Jiaming Sun, Chunhui Ma, Sha Luo, Wei Li and Shouxin Liu

Polymers 2023, 15(3), 638; https://doi.org/10.3390/polym15030638 - 26 Jan 2023

Cited by 1 | Viewed by 1598

Abstract

The global challenge of oil pollution calls for the efficient selective recovery of oil or organics from oil–water mixtures. A pH-responsive carbon foam (CF) made from liquefied larch sawdust (LLS) with switchable wettability was fabricated in this work. After grafted with poly 4-vinyl [...] Read more.

The global challenge of oil pollution calls for the efficient selective recovery of oil or organics from oil–water mixtures. A pH-responsive carbon foam (CF) made from liquefied larch sawdust (LLS) with switchable wettability was fabricated in this work. After grafted with poly 4-vinyl pyridine (P4vp), the CF obtained a switchable wettability surface, which allowed the CF to exhibit superhydrophilicity and superhydrophobicity at different pH levels, respectively. The results revealed that the pH-responsive CF possessed a three-dimensional (3D) spongy-like skeleton and porous structure with a diameter between 50 and 200 µm. Thus, the pH-responsive CF could absorb 15–35 g/g of oil/organics in a neutral aqueous solution at pH = 7 and desorb all the absorbate within 40 s after immersion in an aqueous solution at pH = 1. Moreover, only about 2.8% loss was observed for organic (chloroform) absorption and recovery after reusing up to 15 cycles, which indicated promising prospects in oil and organic recovery. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

13 pages, 8840 KiB

Open AccessArticle

Experimental Study on the Bending and Shear Behaviors of Chinese Paulownia Wood at Elevated Temperatures

by Lingfeng Zhang, Biao Xu, Zhongjie Fang, Chen Li, Xijun Kong, Qianyi Li and Kai Guo

Polymers 2022, 14(24), 5545; https://doi.org/10.3390/polym14245545 - 18 Dec 2022

Cited by 3 | Viewed by 1664

Abstract

Chinese Paulownia wood has been extensively used in the construction of timber buildings and lightweight sandwich structures. However, the bending and shear behaviors at elevated temperatures were not well understood. A total of 162 specimens were tested to investigate the bending, tangential shear, [...] Read more.

Chinese Paulownia wood has been extensively used in the construction of timber buildings and lightweight sandwich structures. However, the bending and shear behaviors at elevated temperatures were not well understood. A total of 162 specimens were tested to investigate the bending, tangential shear, and radial shear performances of Chinese Paulownia wood under temperatures from 20 to 220 °C. It was found that the bending specimens exhibited ductile failure due to the progressive damage after reaching the peak load, while the tangential and radial shear specimens exhibited brittle shear failure along the shear plane. The elevated temperatures had limited effects on the failure modes. Under the same temperature, the retention rate of the modulus of elasticity is significantly higher than that of the modulus of rupture. Moreover, the bending strength, tangential shear strength, and radial shear strength generally and nonlinearly decreased with the increasing temperature. The EN 1995-1-2 design curve for the shear strength of wood at elevated temperatures is conservative for both the tangential and radial shear specimens. However, the design curve may not be adopted to estimate the tangential shear strength at temperatures higher than 220 °C. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

11 pages, 1428 KiB

Open AccessArticle

Mold and Stain Resistance of Bamboo Treated with Pyraclostrobin Fungicide

by Jingpeng Zhang, Mingliang Jiang, Bin Zhang, Yuzhang Wu and Xingxia Ma

Polymers 2022, 14(24), 5537; https://doi.org/10.3390/polym14245537 - 17 Dec 2022

Cited by 3 | Viewed by 2589

Abstract

Bamboo is rich in starch and sugars and can be infected by mold and stain fungi, degrading its performance, shortening its service life, and reducing its utilization value. It is crucial to investigate how to protect bamboo against mold and stain fungi. The [...] Read more.

Bamboo is rich in starch and sugars and can be infected by mold and stain fungi, degrading its performance, shortening its service life, and reducing its utilization value. It is crucial to investigate how to protect bamboo against mold and stain fungi. The zone of inhibition test was used to evaluate the antifungal activity of azoxystrobin, kresoxim-methyl, pyraclostrobin and 3-iodo-2-propynyl-butylcarbamate (IPBC) against stain fungi (Botryodiplodia theobromae, Fusarium moniliforme, and Alternaria alternate) and mold fungi (Aspergillus niger, Penicillium citrinum, and Trichoderma viride) to develop new chemicals to protect bamboo against stain fungi and molds. The inhibitory activity of the composite pyraclostrobin and IPBC with different ratios was evaluated. Water-based formulations of the fungi were used to treat the bamboo, and the mold and stain resistance of the bamboo was investigated at different chemical retention rates. The results showed that the antifungal activity of pyraclostrobin was significantly higher than that of azoxystrobin and kresoxim-methyl. Different degrees of inhibitory activities against the stain and mold fungi were observed, and the inhibitory activity was higher against stain fungi than against molds. The three stain fungi were completely inhibited at a 7:3 ratio of pyraclostrobin to IPBC and 0.1% concentration. As the ratio increased, the inhibitory effect against mixed mold strains improved. The control efficacy of the pyraclostrobin formulations Str-1 and Str-2 at 0.1% concentration was 100% against Alternaria alternate and 70.8% against Fusarium moniliforme. The control efficacy of the composite formulations SI-1 and SI-2 at 0.1% concentration was 100% against all three stain fungi and greater than 91.8% against the mixed mold strains. This study provides new insights into the utilization of pyraclostrobin and its composite formulations as new bamboo antifungal agents. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Graphical abstract

10 pages, 1576 KiB

Open AccessArticle

Effects of Different Delignification and Drying Methods on Fiber Properties of Moso Bamboo

by Yifeng Bai, Wenqing Wang, Yongyue Zhang, Xiangwei Wang, Xinzhou Wang and Jiangtao Shi

Polymers 2022, 14(24), 5464; https://doi.org/10.3390/polym14245464 - 13 Dec 2022

Cited by 8 | Viewed by 2196

Abstract

Bamboo has become an important kind of fibrous raw material in the world due to its fast-growing property and abundance of natural fiber. During the purification and utilization of bamboo fiber, the removal of lignin is vital and it is affected by the [...] Read more.

Bamboo has become an important kind of fibrous raw material in the world due to its fast-growing property and abundance of natural fiber. During the purification and utilization of bamboo fiber, the removal of lignin is vital and it is affected by the chemical treatment system and drying method. In this paper, the effects of three different delignification chemical systems and three drying methods (air drying, drying and freeze drying) on the physical and chemical properties of bamboo fiber were comparatively studied. The results prove that all three delignification techniques can effectively remove lignin from wood, and by utilizing peroxyformic acid and alkaline sodium sulfite, hemicellulose can be removed to a certain extent. With the selective removal of amorphous hemicellulose and lignin and the hydrolysis of cellulose molecular chains in amorphous regions, all three treatments contributed to an increase in the relative crystallinity of cellulose (ranging from 55% to 60%). Moreover, it was found that the drying methods exerted a certain influence on the mechanical properties of fiber. For instance, drying or air drying would improve the tensile strength of fiber significantly, approximately 2–3.5 times that of original bamboo fiber, and the tensile strength of the drying group reached 850–890 MPa. In addition, the alkaline sodium sulfite treatment had little effect on the thermal stability of bamboo fiber, resulting in high thermal stability of the prepared samples, and the residual mass reached 25–37%. On the contrary, the acetic acid/hydrogen peroxide method exerted great influence on the thermal stability of bamboo fiber, giving rise to a relatively poor thermal stability of prepared fibers, and the residual mass was only about 15%. Among the three drying methods, samples under air drying treatment had the highest residual mass, while those under freeze drying had the lowest. To summarize, the alkaline sodium sulfite method is more suitable for preparing bamboo fiber with higher tensile strength and thermal stability. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

11 pages, 2996 KiB

Open AccessArticle

Effect of Structural Design on the Pore Structure, Water Resistance, and Mechanical Properties of Engineered Wood/Bamboo Laminated Composites

by Xuguang Zhu, Xiaoyan Li, Zhiyuan Zhang, Lin Cheng, Jue Wu, Luming Li, Zhenhua Zhang, Qingyuan Liu, Pu Zhao and Fei Rao

Polymers 2022, 14(24), 5386; https://doi.org/10.3390/polym14245386 - 9 Dec 2022

Cited by 2 | Viewed by 1658

Abstract

An important principle in rational manufacturing design is matching the properties of composites to their intended uses. Herein, six laminated composites (LCs) were manufactured using fibrous moso bamboo and poplar veneer units, and their pore structure, water resistance, and mechanical properties were evaluated. [...] Read more.

An important principle in rational manufacturing design is matching the properties of composites to their intended uses. Herein, six laminated composites (LCs) were manufactured using fibrous moso bamboo and poplar veneer units, and their pore structure, water resistance, and mechanical properties were evaluated. The LC density (640–1290 kg/m³) increased significantly with increasing bamboo veneer unit content. The LC surface texture and roughness depended on the density and type of surface layer. With increasing LC density, the water absorption rate (WAR), width swelling rate (WSR), and thickness swelling rate (TSR) decreased exponentially and the mechanical properties increased linearly. This behavior was closely related to the changes in pore structure caused by density. Notably, the water resistance and mechanical properties of the LCs with densities higher than 910 kg/m³ were superior to the highest levels specified in GB/T 20241–2006 for ‘‘laminated veneer lumber’’ and GB/T 30364–2013 for “bamboo scrimber flooring”. Thus, these engineered materials are promising for outdoor structures and flooring. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

14 pages, 3039 KiB

Open AccessArticle

Physical and Mechanical Properties of Novel Multilayer Bamboo Laminated Composites Derived from Bamboo Veneer

by Xuelian Li, Weizhong Zhang, Wencheng Lei, Yaohui Ji, Zhenhua Zhang, Yifan Yin and Fei Rao

Polymers 2022, 14(22), 4820; https://doi.org/10.3390/polym14224820 - 9 Nov 2022

Cited by 2 | Viewed by 1441

Abstract

Compared with wood, bamboo has a special fiber gradient structure. Bamboo fibers have attracted attention as reinforced polymer composites. This study investigated the effects of lamination and fiber volume on the physical and mechanical properties of bamboo laminated composites (BLCs). Six types of [...] Read more.

Compared with wood, bamboo has a special fiber gradient structure. Bamboo fibers have attracted attention as reinforced polymer composites. This study investigated the effects of lamination and fiber volume on the physical and mechanical properties of bamboo laminated composites (BLCs). Six types of BLC were derived by parallel and cross laminating bamboo veneers with high, middle, and low fiber volumes. The results indicated that the laminated structure and fiber volume significantly influenced the BLC properties. Microstructural analysis showed that parallel lamination and low fiber volume were more conducive to resin penetration and enhanced the bonding strength. Both the bending and tensile strengths of the cross lamination were lower than those of the parallel lamination. BLCs made of veneers with high and middle fiber volumes and parallel lamination had the maximum bending and tensile strengths (145.1 and 101.53 MPa, respectively). When tested for water resistance, parallel and cross lamination inhibited expansion in the thickness (TSR, 0.56–2.14%) and width (WSR, 0.07–1.61%) directions, respectively. Laminated structures and veneers with varying fiber volume contents should be chosen according to the specific application scenarios. This study provides a reference for selecting an appropriate BLC structure and fiber volume based on application. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Graphical abstract

12 pages, 2316 KiB

Open AccessArticle

Preparation of Citral Compound and Its Bamboo Antimildew Properties

by Yingying Shan, Shiqin Chen, Jingjing Zhang, Chungui Du, Chunlin Liu, Fei Yang, Wenxiu Yin, Yuran Shao and Yuting Wang

Polymers 2022, 14(21), 4691; https://doi.org/10.3390/polym14214691 - 3 Nov 2022

Cited by 8 | Viewed by 2081

Abstract

To reduce the amount of citral used without reducing the antimildew performance of bamboo, the citral compound preparation process, the distribution of the compound in bamboo, and its antimildew performance were investigated using the Oxford cup method, Fourier-transform infrared spectroscopy, and ultraviolet spectrophotometry. [...] Read more.

To reduce the amount of citral used without reducing the antimildew performance of bamboo, the citral compound preparation process, the distribution of the compound in bamboo, and its antimildew performance were investigated using the Oxford cup method, Fourier-transform infrared spectroscopy, and ultraviolet spectrophotometry. The results revealed that the combination of citral with cinnamaldehyde or thymol may lead to partial chemical reactions, which may change the chemical structure of citral and affect its bacteriostatic properties. The bacteriostatic properties of the citraldehyde thymol compound against common molds of bamboo were considerably superior to those of the citral cinnamaldehyde compound. The limonaldehyde thymol compound showed a low distribution trend outside and vice versa inside in the treated bamboo. The citral thymol compound exhibited good antimildew performance at a concentration of 200 mg/mL. The citral thymol compound could reduce the amount of citral by approximately 67 mg/mL without reducing the antimildew performance of bamboo. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

14 pages, 2172 KiB

Open AccessArticle

Antioxidant-Mediated Modification of Citral and Its Control Effect on Mildewy Bamboo

by Chunlin Liu, Qi Li, Yingying Shan, Chungui Du, Shiqin Chen, Wenxiu Yin, Fei Yang, Yuran Shao and Yuting Wang

Polymers 2022, 14(21), 4652; https://doi.org/10.3390/polym14214652 - 1 Nov 2022

Cited by 1 | Viewed by 1838

Abstract

To reduce the oxidative degradation of citral and improve its antimildew performance, citral was modified with natural antioxidants such as tea polyphenols, ascorbic acid, and theaflavin in the present study. Additionally, the effects of these natural antioxidants on the citral degradation rate and [...] Read more.

To reduce the oxidative degradation of citral and improve its antimildew performance, citral was modified with natural antioxidants such as tea polyphenols, ascorbic acid, and theaflavin in the present study. Additionally, the effects of these natural antioxidants on the citral degradation rate and DPPH radical-scavenging rate, as well as the effectiveness of antioxidant-modified citral in the antimildew treatment of bamboo were investigated. Ascorbic acid, theaflavin, and tea polyphenols improved the antioxidant performance of citral to some extent, and the tea polyphenols exhibited the best antioxidant performance. When the amount of tea polyphenols added to citral reached 1.0%, the oxidative degradation of citral was effectively prevented. Compared with citral, tea-polyphenol-modified citral could reduce the efficacy of the bamboo antimildew treatment against all four mildews and the effectiveness of the antimildew treatment reached 100%. Citral modification with antioxidants reduced the amount of citral required in the treatment, thereby reducing the treatment cost for bamboo mildew. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

13 pages, 2875 KiB

Open AccessArticle

Thermal Degradation and Product Analysis of 3-iodo-2-propyl-butylcarbamate as a Wood Preservative

by Liping Han, Mingliang Jiang, Jingpeng Zhang, Chuang Shao and Qingshuo Zhang

Polymers 2022, 14(21), 4531; https://doi.org/10.3390/polym14214531 - 26 Oct 2022

Cited by 2 | Viewed by 1925

Abstract

The thermal degradation kinetics and degradation products of IPBC during the heating process are investigated herein. Experiments were conducted at isothermal conditions from 60 °C to 150 °C. The remaining IPBC content was analyzed by high-performance liquid chromatography (HPLC) at specific time intervals [...] Read more.

The thermal degradation kinetics and degradation products of IPBC during the heating process are investigated herein. Experiments were conducted at isothermal conditions from 60 °C to 150 °C. The remaining IPBC content was analyzed by high-performance liquid chromatography (HPLC) at specific time intervals for each test, and the kinetic model of IPBC thermal degradation was established. The thermal degradation products of IPBC were studied by ultra-performance liquid chromatography-mass spectrometry (UPLC−MS/MS). The results showed that thermal degradation of IPBC occurred at 70 °C, and the degradation rate increased significantly from 70 °C to 150 °C. The thermal degradation kinetics of IPBC conformed to the first-order reaction and

k = 3.47 \times 10^{12} e^{- 111125 / R T}

from 60 °C to 150 °C. Seven degradation products such as prop-2-yn-1-yl ethylcarbamate and methyl N-butylcarbamate were identified and the degradation reaction pathway and the mechanism of IPBC were proposed, which involved deiodination, demethylation, deethynylation, deethylation, and hydroxylation processes. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Graphical abstract

15 pages, 1943 KiB

Open AccessArticle

Using Statistical Methods to Comparatively Analyze the Visual Characteristics of Flattened Bamboo Boards in Different Bamboo Culms

by Caiping Lian, Xuehua Wang, Hong Chen, Benhua Fei, Xiaoren Pang, Jianchang Lian and Zhihui Wu

Polymers 2022, 14(20), 4327; https://doi.org/10.3390/polym14204327 - 14 Oct 2022

Cited by 2 | Viewed by 1566

Abstract

Different flattened bamboo boards will produce different visual effects, which directly determine consumers’ preferences. However, their visual characteristics were unknown. To clarify the visual effects of flattened bamboo boards in different bamboo culms, the visual, physical, and psychological quantities were firstly studied using [...] Read more.

Different flattened bamboo boards will produce different visual effects, which directly determine consumers’ preferences. However, their visual characteristics were unknown. To clarify the visual effects of flattened bamboo boards in different bamboo culms, the visual, physical, and psychological quantities were firstly studied using their quantitative color and glossiness measurements, combined with quantitative semantic differential and statistical methods. Key results revealed that the values of lightness L* and blue–yellow index b* from the base to the top of the bamboo culms tended to decrease gradually, while green–red index a* values exhibited an increasing trend, and glossiness G_ZL (G_ZT) showed no significant difference. The L* value of bamboo outer layer (30.18) was smaller than that of the outer (61.90) and the inner (68.68), which had an increasing trend from the outside to the inside of the bamboo culm, while the G_ZL (G_ZT) values corresponded to 6.07 (4.66), 4.51 (3.12), and 2.77 (2.55), showing an opposite trend. The a* and b* values present a rise-fall tendency. According to visual psychological assessment, the outer was reflected as an “artificial–decorative”, “smooth–warm”, and “comfort–sophisticated” feeling; the inner had an “artificial–practical”, “smooth–warm”, and “comfort–sophisticated” sense; the bamboo outer layer had an “nature–practical”, “rough–cold”, and “sick–primitive” sense. Furthermore, predictive models for visual psychological quantities were constructed. This work provides a theoretical data basis for furniture design and standard materials application of flattened bamboo boards. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

14 pages, 2140 KiB

Open AccessArticle

Effect of Accelerated Aging on Bamboo Fiber Lunch Box and Correlation with Soil Burial Degradation

by Huan Jiang, Ge Wang, Fuming Chen, Jianchao Deng and Xiaoyi Chen

Polymers 2022, 14(19), 4220; https://doi.org/10.3390/polym14194220 - 8 Oct 2022

Cited by 3 | Viewed by 1992

Abstract

This study aimed to investigate the mechanical property decay that might occur during actual use and soil burial degradation of bamboo fiber lunch boxes. For this, the effects of three accelerated aging methods, namely damp–heat treatment, freeze–thaw cycle, and artificial weathering cycle, on [...] Read more.

This study aimed to investigate the mechanical property decay that might occur during actual use and soil burial degradation of bamboo fiber lunch boxes. For this, the effects of three accelerated aging methods, namely damp–heat treatment, freeze–thaw cycle, and artificial weathering cycle, on the tensile strength, dynamic viscoelasticity, and chemical composition of bamboo fiber lunch boxes were compared, and a correlation of their mechanical property decay with soil burial degradation was established to obtain an acceleration factor (SAF) with aging time as a reference. The results showed that the mechanical properties of the bamboo fiber lunch box decreased to different degrees under the three accelerated methods, and the tensile strength decreased to less than 50% after 36 h of damp–heat treatment, 5 freeze–thaw cycles, and 11 artificial weathering cycles. However, after 10 days, the mechanical property of lunch box in soil degradation decreased by more than 50%. Infrared spectroscopy demonstrated rapid hemicellulose degradation during damp–heat treatment and freeze–thaw cycle, as well as a minor quantity of lignin, and a significant amount of lignin under artificial weathering cycle. With the freeze–thaw cycle and the artificial weathering cycle, the relative crystallinity dropped quickly, by 32.3% and 21.5%, respectively, but under damp–heat treatment, the crystallinity dropped barely, by 43.5%. The damage caused by the freeze–thaw cycle to the mechanical properties of bamboo fiber lunch boxes was greater than that by the damp–heat treatment and artificial weathering cycle. The fluctuation of SAF under freeze–thaw cycle was also more drastic. Compared to the artificial weathering cycle, the damp–heat treatment was more stable and reliable in predicting the decay law of soil burial degradation tensile strength of bamboo fiber lunch boxes. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

20 pages, 3960 KiB

Open AccessArticle

Effects of Accelerated Ageing by Humidity and Heat Cycles on the Quality of Bamboo

by Hao Jia, Lei Chen, Benhua Fei, Fengbo Sun and Changhua Fang

Polymers 2022, 14(19), 4052; https://doi.org/10.3390/polym14194052 - 27 Sep 2022

Cited by 4 | Viewed by 1972

Abstract

The effect of humidity and heat environmental conditions on the durability of conventional bamboo materials is a pressing issue in the reserving phase of biomass materials. In this study, the relationship between the main physicochemical, pyrolytic, and mechanical properties of bamboo before and [...] Read more.

The effect of humidity and heat environmental conditions on the durability of conventional bamboo materials is a pressing issue in the reserving phase of biomass materials. In this study, the relationship between the main physicochemical, pyrolytic, and mechanical properties of bamboo before and after ageing has been investigated. Exposure of engineered bamboo raw materials with moisture content up to 10% to alternating humidity and heat cycles (20 °C 98% RH-30 °C 64% RH-40 °C 30% RH) of ageing (HHT) causes degradation of the chemical polymer matrix. Byk Gardner 6840 color difference meter, X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), compression intensity, thermogravimetric-infrared spectroscopy (TG-IR), and density changes are used to assess the quality of the material before and after ageing. No significant changes in the moisture content within the range of 6.12 ± 0.327 after two weeks of the engineered bamboo during wet thermal cyclic ageing were determined. However, there were significant differences in mass loss (7.75–9.93 g), cellulose crystallinity, chemical changes, compression strength, and pyrolytic properties. Differences in specimen colors were observed during 10 weeks of the accelerated humidity heat cycling ageing, and TCD variations ranged from 3.75 to 20.08 and from 0.25 and 3.24, respectively. Reduced cellulose crystallinity (36.459–22.638%), axial compressive strength (63.07–88.09 MPa), and modulus of rupture (2409–4286 MPa) were found during aging, whereas deformation and ductility properties were improved. Both natural and humidity heat ageing improve thermal stability and peak pyrolysis rates (0.739–0.931; 0.731–0.797). Humidity heat cyclic ageing will assist in the design and risk assessment of warehousing environments for industrial applications. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

12 pages, 20255 KiB

Open AccessArticle

Compressive Mechanical Properties of Larch Wood in Different Grain Orientations

by Jingcheng Sun, Rongjun Zhao, Yong Zhong and Yongping Chen

Polymers 2022, 14(18), 3771; https://doi.org/10.3390/polym14183771 - 9 Sep 2022

Cited by 6 | Viewed by 2392

Abstract

As a green and low-carbon natural polymer material, wood has always been popular in engineering applications owing to its excellent physical and mechanical properties. In this study, compression tests in conjunction with in situ test methods (DIC method) were used to investigate the [...] Read more.

As a green and low-carbon natural polymer material, wood has always been popular in engineering applications owing to its excellent physical and mechanical properties. In this study, compression tests in conjunction with in situ test methods (DIC method) were used to investigate the compression mechanism of wood samples in the longitudinal, radial, and tangential directions. The macroscopic failure modes, energy dissipation results, and variations in the strain field were analyzed. The results showed that the load–displacement curve in each grain orientation included three stages: an elasticity stage, yield stage, and strengthening stage. Both the compressive strength and elastic modulus in the longitudinal direction were significantly higher than those in the radial and tangential directions, but there was no significant difference between the radial and tangential directions. Specimens in the longitudinal direction mainly presented fiber buckling, fiber shear slippage, and fiber fracture failure; in radial directions mainly presented compression compaction of the fiber cells; and in the tangential directions presented buckling and shear failure of the laminar layers. The energy absorption in the longitudinal direction was better than in the other directions. The strain changed significantly in the loading direction in the elastic stage while the shear strain changed remarkably in the yield stage in each grain orientation. In this paper, the compression mechanical properties of larch wood in different grain orientations were studied to provide a reference for its safe application in engineering. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

Review

Jump to: Research

21 pages, 2131 KiB

Open AccessReview

Review of Konjac Glucomannan Structure, Properties, Gelation Mechanism, and Application in Medical Biology

by Yilan Sun, Xiaowei Xu, Qinhua Zhang, Di Zhang, Xiaoyu Xie, Hanlin Zhou, Zhenzhen Wu, Renyi Liu and Jie Pang

Polymers 2023, 15(8), 1852; https://doi.org/10.3390/polym15081852 - 12 Apr 2023

Cited by 18 | Viewed by 9411

Abstract

Konjac glucomannan (KGM) is a naturally occurring macromolecular polysaccharide that exhibits remarkable film–forming and gel–forming properties, and a high degree of biocompatibility and biodegradability. The helical structure of KGM is maintained by the acetyl group, which plays a crucial role in preserving its [...] Read more.

Konjac glucomannan (KGM) is a naturally occurring macromolecular polysaccharide that exhibits remarkable film–forming and gel–forming properties, and a high degree of biocompatibility and biodegradability. The helical structure of KGM is maintained by the acetyl group, which plays a crucial role in preserving its structural integrity. Various degradation methods, including the topological structure, can enhance the stability of KGM and improve its biological activity. Recent research has focused on modifying KGM to enhance its properties, utilizing multi–scale simulation, mechanical experiments, and biosensor research. This review presents a comprehensive overview of the structure and properties of KGM, recent advancements in non–alkali thermally irreversible gel research, and its applications in biomedical materials and related areas of research. Additionally, this review outlines prospects for future KGM research, providing valuable research ideas for follow–up experiments. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

23 pages, 4572 KiB

Open AccessReview

Polysaccharides Are Effective Inhibitors of Natural Gas Hydrate Formation

by Alsu Venerovna Fakhreeva, Vasily Viktorovich Nosov, Alexander Iosifovich Voloshin and Vladimir Anatolyevich Dokichev

Polymers 2023, 15(7), 1789; https://doi.org/10.3390/polym15071789 - 4 Apr 2023

Cited by 8 | Viewed by 2938

Abstract

This review covers the types and applications of chemical inhibitors of gas hydrate formation in the oil and gas industry. The main directions of the development of new types of highly effective and environmentally safe “green” kinetic hydrate inhibitors (KHIs) based on biopolymers [...] Read more.

This review covers the types and applications of chemical inhibitors of gas hydrate formation in the oil and gas industry. The main directions of the development of new types of highly effective and environmentally safe “green” kinetic hydrate inhibitors (KHIs) based on biopolymers are analyzed. The structure, physicochemical properties, efficiency of gas hydrate formation inhibition, and commercial prospects of polysaccharides in preventing and controlling the formation of gas hydrates are considered. The criteria for their selection, current experimental data, and the mechanism of inhibition are presented. Recent research in the development of cost-effective, efficient, and biodegradable KHIs for industrial applications in the oil and gas industry is also presented. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Graphical abstract

27 pages, 5107 KiB

Open AccessReview

Polysaccharides as Effective and Environmentally Friendly Inhibitors of Scale Deposition from Aqueous Solutions in Technological Processes

by Alsu Venerovna Fakhreeva, Vasily Viktorovich Nosov, Alexander Iosifovich Voloshin and Vladimir Anatolyevich Dokichev

Polymers 2023, 15(6), 1478; https://doi.org/10.3390/polym15061478 - 16 Mar 2023

Cited by 6 | Viewed by 2098

Abstract

In this paper, we consider natural and modified polysaccharides for use as active ingredients in scale deposition inhibitors to prevent the formation of scale in oil production equipment, heat exchange equipment, and water supply systems. Modified and functionalized polysaccharides with a strong ability [...] Read more.

In this paper, we consider natural and modified polysaccharides for use as active ingredients in scale deposition inhibitors to prevent the formation of scale in oil production equipment, heat exchange equipment, and water supply systems. Modified and functionalized polysaccharides with a strong ability to inhibit the formation of deposits of typical scale, such as carbonates and sulfates of alkaline earth elements found in technological processes, are described. This review discusses the mechanisms of the inhibition of crystallization using polysaccharides, and the various methodological aspects of evaluating their effectiveness are considered. This review also provides information on the technological application of scale deposition inhibitors based on polysaccharides. Special attention is paid to the environmental aspect of the use of polysaccharides in industry as scale deposition inhibitors. Full article

(This article belongs to the Special Issue Eco-Friendly Supramolecular Polymeric Materials)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Eco-Friendly Supramolecular Polymeric Materials

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Related Special Issue

Published Papers (23 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI