Article
Polymer Science
Yao Chen, Zhuyu Bai, Xiaoyu Xu, Jianbing Guo, Xiaolang Chen, Shaw Ling Hsu, Zongcheng Lu, Hong Wu
Summary: Researchers have developed a hybrid expandable graphite (EG) intumescent flame retardant for improving the fire safety of rigid polyurethane foam (RPUF). The flame-retardant properties of RPUF composites with Hexachlorocyclotriphosphazene (HCCP) self-assembled on the surface and interlamination of EG (HCCP@EG) were significantly enhanced, achieving a UL-94 V-0 level and a limiting index higher than 27.0%. The presence of HCCP also improved the mechanical property of RPUF composites through enhancing the interface compatibility between EG and RPUF.
Article
Nanoscience & Nanotechnology
Brandon L. Williams, Hao Ding, Zaili Hou, Patrick O. Paul, Frank A. Lewis, Andrew T. Smith, Luyi Sun
Summary: A one-pot self-assembled nanocoating of PVA and MMT with well-defined nanostructure was spray coated onto double-walled corrugated cardboard, effectively inhibiting flame spread and improving flame retardancy through the formation of a dense char layer after burning tests.
ADVANCED COMPOSITES AND HYBRID MATERIALS
(2021)
Article
Thermodynamics
Katalin Bocz, Ferenc Ronkay, Daniel Vadas, Bela Molnar, Daniel Gere, Tibor Czigany, Gyorgy Marosi
Summary: The supercritical CO2-assisted extrusion technique was used to produce flame retarded foams from recycled PET. The addition of flame retardants and chain extenders effectively compensated for the increased degradation rate during production, allowing for the production of low-density foams with uniform microcellular structure and prominent flame retardant characteristics.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Engineering, Environmental
Wei Zhao, Hai-Bo Zhao, Jin-Bo Cheng, Wenxiong Li, Jiayan Zhang, Yu-Zhong Wang
Summary: This article introduces a formaldehyde-free phosphorus-containing polysiloxane coating for flame retardancy of EPS foam. The coating acts as both an adhesive and a flame retardant, providing durable thermal insulation and forming a graphited char layer to isolate oxygen, heat, combustible compounds, and smoke particles during combustion. EPS composites treated with this coating exhibit high fire safety and excellent comprehensive performance.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Materials Science, Paper & Wood
Hongliang Ding, Shuilai Qiu, Xin Wang, Lei Song, Yuan Hu
Summary: In this study, composite foams of PA-GZ-CNF were successfully prepared to enhance the flame retardancy of CNF foams without significantly affecting their thermal conducting property. The composite foams showed higher LOI value, better flame retardant rating, and formed a protective char layer that prevented the release of thermal decomposition volatiles.
Article
Polymer Science
Zheng Cui, Yu Chen, Dan Meng, Shuheng Wang, Tongbing Sun, Jun Sun, Hongfei Li, Xiaoyu Gu, Sheng Zhang
Summary: In this study, reactive flame retardants with hydroxyl groups were synthesized and introduced into rigid polyurethane foams. The flame retardant efficiency of the foams was improved while maintaining their mechanical properties and thermal conductivity.
POLYMER DEGRADATION AND STABILITY
(2023)
Article
Polymer Science
L. Maddalena, C. Paravidino, A. Fina, F. Carosio
Summary: Recent research has shown that water-based coatings with platelet-like nanoparticles can effectively enhance the flame retardancy of open cell flexible foams. However, the current limitations of this approach include the need for multiple deposition steps and limited durability of the coatings under multiple compression cycles. This paper addresses these issues by developing a few-step deposition procedure to produce durable flame retardant coatings for foam materials.
POLYMER DEGRADATION AND STABILITY
(2023)
Article
Forestry
Zhouyao Yue, Huashan Wang, Mingxiu Zhang, Meiyi Wang
Summary: In this study, polylactic acid (PLA)/epichlorohydrin modified pinewood flour (EWF) composites were prepared and systematically investigated for their mechanical, thermal, and rheological properties. The results showed that the addition of epichlorohydrin modified pinewood flour (EWF) significantly improved the tensile and impact properties of the biocomposite, as well as enhanced the crystallinity. Additionally, the PLA/EWF composite exhibited improved storage and loss modulus due to increased molecular entanglement and crosslinking.
EUROPEAN JOURNAL OF WOOD AND WOOD PRODUCTS
(2022)
Article
Engineering, Environmental
Tuan An Nguyen, Tuyet Minh Nguyen Ha, Binh T. Nguyen, Dat Ha, Tuan Vu Vo, Dang Mao Nguyen, Dang Khoa Vo, Ngoc Thuy Nguyen, Tuong Vy Nguyen, DongQuy Hoang
Summary: In this study, bamboo powder was used to synthesize bio-based polyurethane foam (B-PUf) through liquification and microwave conditions. The B-polyol mainly consisted of carbon derivatives, including sugars, phenolic compounds, ethers, and esters. The B-PUf exhibited a heterogeneous morphology with cell size range and low density. The lignin derivatives in B-polyol significantly improved the thermal stability of B-PUf. The study also demonstrated the potential of bamboo as an alternative to fossil fuel and its contribution to bio-based content in PU foam materials.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Polymer Science
Weijiang Huang, Kui Wang, Chunyun Tu, Xiaolu Xu, Qin Tian, Chao Ma, Qiuping Fu, Wei Yan
Summary: This study investigated the synergistic effects of PN-DOPO and OMMT on the flame retardancy, thermal stability, and mechanical properties of PP composites. The results showed that the combination of PN-DOPO and OMMT improved the fire resistance and overall performance of the PP composites. Rheological and TGA analysis indicated enhanced network structure and thermal stability in the presence of OMMT.
Article
Chemistry, Multidisciplinary
Lorenza Maddalena, Julio Gomez, Alberto Fina, Federico Carosio
Summary: This study investigated the effects of different sizes of graphite oxide nanoplates on the assembly and flame-retardant properties of coatings on polyurethane foams. The results showed that CHIT/GO assemblies could effectively slow down foam combustion, reduce foam weight, and enhance mechanical strength, with the density of CHIT/GO interfaces playing a key role in controlling the flame-retardant efficiency and mechanical properties of the coatings.
Article
Materials Science, Multidisciplinary
Fu-Rong Zeng, Bo-Wen Liu, Zi-Hao Wang, Jia-Yan Zhang, Xue-Lian Chen, Hai-Bo Zhao, Yu-Zhong Wang
Summary: In this study, multifunctional biophenolic nanospheres were developed, which can be stimuli-responsive and reversibly assembled based on multiple directional interactions. These nanospheres can be repeatedly disassembled, removed, reassembled, and reused sustainably. They show excellent mechanical enhancement, aging resistance, and durable flame retardancy in thermoset foams.
ACS MATERIALS LETTERS
(2023)
Article
Biochemistry & Molecular Biology
Jiashui Lan, Dingsi Li, Wei Zhong, Wenhui Luo, Huagui Zhang, Mingfeng Chen
Summary: Iron-loaded polydopamine functionalized montmorillonite can improve the flame retardancy and mechanical properties of epoxy resin.
Article
Materials Science, Multidisciplinary
Yajun Chen, Mengqi Li, Fenghao Hao, Chunzhuang Yang
Summary: By synthesizing a phosphorus-containing organosilicon compound (PCOC) to modify organic-montmorillonite (M-OMMT) and combining it with ammonium polyphosphate (APP), the flame retardancy of rigid polyurethane foam (RPUF) composites was improved, reducing peak heat release rate and total smoke release while increasing residual char yield.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Yajun Chen, Mengqi Li, Fenghao Hao, Chunzhuang Yang
Summary: A phosphorus-containing organosilicon compound was synthesized to modify organic-montmorillonite, improving the flame retardancy of rigid polyurethane foam composites. Thermal stability and flame retardancy were studied using various tests, showing enhanced performance after modification.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Chemistry, Applied
Li Zha, Shennan Wang, Lars A. Berglund, Qi Zhou
Summary: In this study, mixed-linkage (1,3;1,4)-beta-D-glucan (MLG) from barley was used as a rehydration medium to improve the redispersion and recycling of dried cellulose nanofibrils (CNFs). MLG exhibited an intrinsic affinity to both cellulose and water molecules, similar to plant cell wall. Coating CNFs with MLG facilitated the rehydration of individualized CNFs network. The addition of 10 wt% barley MLG did not affect the mechanical properties of CNF/MLG composites, and the dried CNF/MLG composite film could be successfully redispersed in water and recycled with well-maintained mechanical properties, unlike lichenan, cationic starch, and xyloglucan.
CARBOHYDRATE POLYMERS
(2023)
Article
Chemistry, Multidisciplinary
Gabriella G. Mastantuoni, Van Chinh Tran, Isak Engquist, Lars A. Berglund, Qi Zhou
Summary: To meet the growing demand for sustainable electronic devices, developing lightweight and mechanically strong wood structures for conducting composites is highly desirable. Researchers have successfully fabricated highly conductive wood/polypyrrole composites by modifying native lignin in wood cell walls and polymerizing pyrrole. By treating wood veneers with sodium sulfite under neutral conditions, researchers obtained sulfonated wood veneers with increased porosity and well-preserved cell wall structures containing native lignin and lignosulfonates. The composite achieved high conductivity and specific pseudocapacitance, making it suitable for sustainable energy applications.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Jonas Garemark, E. Perea-Buceta, Martin Felhofer, Bin Chen, Maria F. Cortes Ruiz, Ioanna Sapouna, Notburga Gierlinger, Ilkka Antero Kilpelainen, Lars A. . Berglund, Yuanyuan Li
Summary: In this work, strong shape-memory bio-aerogels with high specific surface areas and low thermal conductivity were prepared through a one-step treatment of native wood. The methodology developed for nanoscale reassembly of wood is a significant advancement for the design of biobased shape-memory aerogels.
Article
Materials Science, Multidisciplinary
Ying Gao, Farsa Ram, Bin Chen, Jonas Garemark, Lars Berglund, Hongqi Dai, Yuanyuan Li
Summary: Due to its hierarchical structure, wood can generate electricity from mechanical energy through piezoelectric behavior. This study presents a scalable method to synthesize wood/ZnO composites with multilayered ZnO morphologies for efficient mechanical energy conversion. The synthesis process involves fabricating charged wood templates, infiltrating precursors, and hydrothermally growing ZnO, resulting in controlled ZnO morphologies and maintaining the hierarchical structure. Stereo-digital image correlation reveals that the homogeneous distribution of multilayered ZnO enhances piezoelectric performance. The wood/ZnO composite exhibits an output voltage of 1.5 V and an output current of 2.91 nA under periodic mechanical compression (8-10 N) for 300 cycles. The scalable synthesis strategy and excellent piezoelectric performance are crucial for the design of advanced wood nanocomposites for sustainable and efficient energy conversion systems.
MATERIALS & DESIGN
(2023)
Article
Chemistry, Multidisciplinary
Salla Koskela, Shennan Wang, Lengwan Li, Li Zha, Lars A. A. Berglund, Qi Zhou
Summary: Nature has developed enzymes that can alter the wood cell wall structure, providing eco-friendly ways to customize the microstructure of wood for high-performance materials. In this study, an oxidative enzyme called lytic polysaccharide monooxygenase (LPMO) was used to modify the cell wall structure of delignified wood under mild reaction conditions. The enzymatic oxidation led to nanofibrillation of cellulose microfibril bundles, allowing the delignified wood to be densified into transparent anisotropic films under ambient conditions and low pressure. The enzymatic nanofibrillation promoted microfibril fusion and improved the adhesion between neighboring wood fiber cells, resulting in enhanced mechanical performance of the films in both longitudinal and transverse directions. This research advances our understanding of LPMO-induced microstructural changes in wood and provides an environmentally friendly alternative to harsh chemical treatments and energy-intensive densification processes, thus contributing to sustainable production of high-performance wood-derived materials.
Article
Materials Science, Multidisciplinary
Marcus Vinicius Tavares da Costa, Lengwan Li, Lars A. Berglund
Summary: In this study, thin clay coatings were deposited on polymeric materials using water dispersion technique to improve the gas barrier properties and fire retardancy. The mechanical properties of the coatings were difficult to assess due to their thinness (1 μm). In-situ tests using a micro tensile stage in a scanning electron microscope revealed a thickness-dependent microcracking mechanism, and Weibull parameters for coating fracture were extracted. A micromechanical finite element formulation provided values for interfacial shear strength (5 MPa) and interfacial fracture toughness (1 J/m2). The method can be extended to study other combinations of brittle coating-ductile substrates.
MATERIALS & DESIGN
(2023)
Article
Multidisciplinary Sciences
Van Chinh Tran, Gabriella G. Mastantuoni, Marzieh Zabihipour, Lengwan Li, Lars Berglund, Magnus Berggren, Qi Zhou, Isak Engquist
Summary: The discovery of mass transport in plants has led to the development of low-cost and sustainable wood-based electronics. In this study, a wood electrochemical transistor (WECT) was created using conductive wood (CW) for all three electrodes, prepared through a two-step process. The modified wood exhibited high electrical conductivity due to the incorporation of PEDOT:PSS microstructures. The WECT showed promising performance for electrical current modulation and demonstrated potential for bio-based electronic devices.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Chemistry, Multidisciplinary
Celine Montanari, Hui Chen, Matilda Lidfeldt, Josefin Gunnarsson, Peter Olsen, Lars A. Berglund
Summary: The sustainable development of functional energy-saving building materials is important for reducing thermal energy consumption and promoting natural indoor lighting. A novel fully bio-based transparent wood biocomposite for thermal energy storage, with excellent heat storage properties, tunable optical transmittance, and mechanical performance, is introduced. The bio-based TW holds great potential as scalable and sustainable transparent heat storage solution.
Article
Multidisciplinary Sciences
Shennan Wang, Lengwan Li, Li Zha, Salla Koskela, Lars A. Berglund, Qi Zhou
Summary: Researchers have developed a method to fabricate strong transparent wood composites by using wood xerogel that allows solvent-free infiltration of resin monomers into the wood cell wall under ambient conditions. The wood xerogel has a high mesopore volume and can provide precise control of the microstructure, wood volume fraction, and mechanical properties for the transparent wood composites without compromising the optical transmittance. This approach shows potential scalability and can be used to prepare large-sized transparent wood composites with high wood volume fraction.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Lengwan Li, Pan Chen, Lilian Medina, Lin Yang, Yoshiharu Nishiyama, Lars A. Berglund
Summary: Cellulose nanofibrils (CNF) and 2D silicate nanoplatelet reinforcement readily form multifunctional composites by vacuum-assisted self-assembly from hydrocolloidal mixtures. Synchrotron X-ray scattering techniques were used to monitor the structural development of CNF and montmorillonite (MTM) during drying from water and ethanol. Changes in the nanoscale structure and orientation of CNF and MTM were investigated, confirming the residual drying strains and the formation of tactoid platelet stacks. The ordering processes take place during drying, while the constituent nanoparticles in the swollen gel already have a fixed location after filtration.
Article
Chemistry, Applied
Xuan Yang, Lengwan Li, Yoshiharu Nishiyama, Michael S. Reid, Lars A. Berglund
Summary: A facile preparation method using low energy kitchen blenders is reported, in which the dispersion, exfoliation, and mixing of colloidal cellulose nanofibrils (CNFs) and clay nanoparticles are achieved in one step. The energy demand is reduced by about 97% compared to the conventional method, and the resulting composites exhibit higher strength and work to fracture. The results indicate favorable effects of hemicellulose-rich, negatively charged pulp fibers and corresponding CNFs on CNF disintegration and colloidal stability, facilitating substantial CNF/clay interfacial interaction and providing a more sustainable and industrially relevant processing concept for strong CNF/clay nanocomposites.
CARBOHYDRATE POLYMERS
(2023)
Article
Materials Science, Paper & Wood
Arun Srikanth Sridhar, Lars A. Berglund, Jakob Wohlert
Summary: The contact angles of water and various organic liquids on native and acetylated cellulose were calculated using molecular dynamics simulations. The wetting behavior was found to be influenced by the liquid surface tension. Acetylation decreased the work of adhesion to most liquids, including nonpolar ones, while others were unaffected. Water showed the highest affinity to both native and acetylated cellulose. These findings have implications for liquid infiltration of nanocellulose networks and the interaction between cellulose and different liquids.
Article
Materials Science, Composites
Bin Chen, Celine Montanari, Sergei Popov, Lars A. Berglund
Summary: A parametric model is proposed for simulating wood microstructures, which can generate complex 3D structures with realism and variability. The model can be used to study the mechanical, optical, and hydrodynamic properties of composite materials, as well as for training deep learning networks.
COMPOSITES SCIENCE AND TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Gabriella G. Mastantuoni, Lengwan Li, Hui Chen, Lars A. Berglund, Qi Zhou
Summary: A high-strength, transparent, UV-shielding, and recyclable thin wood film is prepared by in situ sulfonation without additional binder or resin. The preserved wood components and natural fiber alignment contribute to the enhanced mechanical and optical properties of the hot-pressed films. The films also exhibit UV-blocking capability and can be recycled into discrete wood fibers due to the sulfonate groups endowed by the in situ sulfonation.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
