Pub Date : 2024-12-20DOI: 10.1016/j.compscitech.2024.111025
William E. Guin, John V. Bausano, Ashley N. Taets, Alan T. Nettles, Scott Ragasa
Adhesively bonded joints with various levels of porosity in the adhesive layer are examined via X-ray computed tomography (CT) and Mode I fracture toughness testing. Bonded assemblies consisting of woven carbon fiber/epoxy composite adherends and a toughened epoxy film adhesive are considered. Porosity is induced in the adhesive layer through the use of shims during the manufacturing process. X-ray CT and accompanying image processing is used to characterize bondline thicknesses and void content in each Mode I fracture toughness specimen considered. Mode I fracture toughness tests are carried out to quantitatively assess the effects of porosity in the adhesive layer and post-test optical microscopy is used to examine the relationships between fracture toughness and fracture processes. This experimental approach is used to establish relationships among bondline thickness, void content, Mode I fracture toughness, and failure modes in an effort to correlate quantifiable physical parameters to adhesively bonded joint structural performance.
{"title":"Characterization of fracture behavior in adhesively bonded joints with porosity in the adhesive layer using X-ray computed tomography","authors":"William E. Guin, John V. Bausano, Ashley N. Taets, Alan T. Nettles, Scott Ragasa","doi":"10.1016/j.compscitech.2024.111025","DOIUrl":"10.1016/j.compscitech.2024.111025","url":null,"abstract":"<div><div>Adhesively bonded joints with various levels of porosity in the adhesive layer are examined via X-ray computed tomography (CT) and Mode I fracture toughness testing. Bonded assemblies consisting of woven carbon fiber/epoxy composite adherends and a toughened epoxy film adhesive are considered. Porosity is induced in the adhesive layer through the use of shims during the manufacturing process. X-ray CT and accompanying image processing is used to characterize bondline thicknesses and void content in each Mode I fracture toughness specimen considered. Mode I fracture toughness tests are carried out to quantitatively assess the effects of porosity in the adhesive layer and post-test optical microscopy is used to examine the relationships between fracture toughness and fracture processes. This experimental approach is used to establish relationships among bondline thickness, void content, Mode I fracture toughness, and failure modes in an effort to correlate quantifiable physical parameters to adhesively bonded joint structural performance.</div></div>","PeriodicalId":283,"journal":{"name":"Composites Science and Technology","volume":"261 ","pages":"Article 111025"},"PeriodicalIF":8.3,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.1016/j.compscitech.2024.111023
Zhicheng Feng , Peng Liu , Shanyong Xuan , Yimeng Shan , Xuefeng Yao
This study provides a systematic investigation of the perforation resistance and failure mechanisms of scarf-repaired composite laminates under high-velocity impact. First, a geometric model of the scarf-repaired laminate was established based on a rate-dependent constitutive equation, with the adhesive layer modeled using the Cowper-Symonds constitutive law, both implemented in ABAQUS/Explicit. Second, model parameters were calibrated using experimental data from the literature, and the numerical predictions aligned well with the experimental results, validating the model's accuracy in predicting the laminate response under high-velocity impact. Finally, various impact conditions, including impact velocity (angle and speed), locations and different scarf angles, were simulated to systematically analyze the impact resistance and failure modes of the repaired structure. This research provides theoretical and practical insights into the design and engineering applications of damage repair in composite structures.
{"title":"High-velocity impact behavior of scarf-repaired composite laminates","authors":"Zhicheng Feng , Peng Liu , Shanyong Xuan , Yimeng Shan , Xuefeng Yao","doi":"10.1016/j.compscitech.2024.111023","DOIUrl":"10.1016/j.compscitech.2024.111023","url":null,"abstract":"<div><div>This study provides a systematic investigation of the perforation resistance and failure mechanisms of scarf-repaired composite laminates under high-velocity impact. First, a geometric model of the scarf-repaired laminate was established based on a rate-dependent constitutive equation, with the adhesive layer modeled using the Cowper-Symonds constitutive law, both implemented in ABAQUS/Explicit. Second, model parameters were calibrated using experimental data from the literature, and the numerical predictions aligned well with the experimental results, validating the model's accuracy in predicting the laminate response under high-velocity impact. Finally, various impact conditions, including impact velocity (angle and speed), locations and different scarf angles, were simulated to systematically analyze the impact resistance and failure modes of the repaired structure. This research provides theoretical and practical insights into the design and engineering applications of damage repair in composite structures.</div></div>","PeriodicalId":283,"journal":{"name":"Composites Science and Technology","volume":"261 ","pages":"Article 111023"},"PeriodicalIF":8.3,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.1016/j.compscitech.2024.111022
Yu Wen, Jicai Liang, Songyue Yang, Yi Li, Ce Liang
Magnetorheological Elastomers (MREs) have garnered significant attention in auxiliary forming due to their controllable mechanical properties. This study designs and prepares several styrene-butadiene rubber (SBR) MREs containing carbonyl iron powders (CIPs). The effects of different particle contents and magnetic field strengths on the sectional distortion in rectangular aluminum profile bend-twist deformation are investigated through experiments and ABAQUS numerical simulations. The results indicate that CIPs content, CB/CNT content, and magnetic field strength significantly impact the magneto-mechanical properties of MREs. The optimal suppression of sectional distortion in rectangular profiles is observed with 80 wt% CIPs and 2 wt% CB/CNT under a magnetic field strength of 400 mT, reducing the maximum collapse rate from 13.17 % to 6.85 % and the maximum bulge rate from 1.40 % to 0.98 %.
{"title":"Effects of magnetorheological elastomer as inner support material on sectional distortion in aluminum profile bend-twist forming","authors":"Yu Wen, Jicai Liang, Songyue Yang, Yi Li, Ce Liang","doi":"10.1016/j.compscitech.2024.111022","DOIUrl":"10.1016/j.compscitech.2024.111022","url":null,"abstract":"<div><div>Magnetorheological Elastomers (MREs) have garnered significant attention in auxiliary forming due to their controllable mechanical properties. This study designs and prepares several styrene-butadiene rubber (SBR) MREs containing carbonyl iron powders (CIPs). The effects of different particle contents and magnetic field strengths on the sectional distortion in rectangular aluminum profile bend-twist deformation are investigated through experiments and ABAQUS numerical simulations. The results indicate that CIPs content, CB/CNT content, and magnetic field strength significantly impact the magneto-mechanical properties of MREs. The optimal suppression of sectional distortion in rectangular profiles is observed with 80 wt% CIPs and 2 wt% CB/CNT under a magnetic field strength of 400 mT, reducing the maximum collapse rate from 13.17 % to 6.85 % and the maximum bulge rate from 1.40 % to 0.98 %.</div></div>","PeriodicalId":283,"journal":{"name":"Composites Science and Technology","volume":"261 ","pages":"Article 111022"},"PeriodicalIF":8.3,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-17DOI: 10.1016/j.compscitech.2024.111021
Siyang Wu, Licheng Guo, Zhixing Li, Tao Zheng, Junfeng Ding, Fenghao Jia
Developing an efficient and accurate scheme for meso-micro concurrent damage evolution analysis of 3D woven composites (3DWC) is challenging. In our work, a concurrent multiscale scheme FFT-SCA is proposed to capture the meso-micro damage evolution of 3DWC. In the scheme, the non-linear behavior of the mesoscale 3DWC representative volume element (RVE) is solved by Fast Fourier Transform (FFT) method, and the non-linear behavior of the microscale yarn RVE is solved concurrently by Self-consistent clustering analysis (SCA) method. The two-scale computations are dynamically coupled based on the homogenization theory. Benefiting from this, there is no need to define mesoscopic constitutive models and calibrate the difficult-to-obtain mesoscale parameters, such as the fracture toughness and strengths of yarns. The FFT-SCA scheme is utilized to predict the failure strength and meso-micro damage evolution of 3DWC. The comparison of the predictions with experiments indicates that the FFT-SCA method has high prediction accuracy for the tensile strength of 3DWC. The high-fidelity mesoscale stress field and cluster-based microscale damage field can be simultaneously captured, which is not available for one-scale Finite Element method (FEM) or experiments. The FFT-SCA scheme enables controllable computational dimensions while guaranteeing the accuracy of meso-micro damage evolution.
{"title":"A concurrent multiscale scheme FFT-SCA for meso-micro damage evolution of 3D woven composites independent of mesoscopic material parameters","authors":"Siyang Wu, Licheng Guo, Zhixing Li, Tao Zheng, Junfeng Ding, Fenghao Jia","doi":"10.1016/j.compscitech.2024.111021","DOIUrl":"10.1016/j.compscitech.2024.111021","url":null,"abstract":"<div><div>Developing an efficient and accurate scheme for meso-micro concurrent damage evolution analysis of 3D woven composites (3DWC) is challenging. In our work, a concurrent multiscale scheme FFT-SCA is proposed to capture the meso-micro damage evolution of 3DWC. In the scheme, the non-linear behavior of the mesoscale 3DWC representative volume element (RVE) is solved by Fast Fourier Transform (FFT) method, and the non-linear behavior of the microscale yarn RVE is solved concurrently by Self-consistent clustering analysis (SCA) method. The two-scale computations are dynamically coupled based on the homogenization theory. Benefiting from this, there is no need to define mesoscopic constitutive models and calibrate the difficult-to-obtain mesoscale parameters, such as the fracture toughness and strengths of yarns. The FFT-SCA scheme is utilized to predict the failure strength and meso-micro damage evolution of 3DWC. The comparison of the predictions with experiments indicates that the FFT-SCA method has high prediction accuracy for the tensile strength of 3DWC. The high-fidelity mesoscale stress field and cluster-based microscale damage field can be simultaneously captured, which is not available for one-scale Finite Element method (FEM) or experiments. The FFT-SCA scheme enables controllable computational dimensions while guaranteeing the accuracy of meso-micro damage evolution.</div></div>","PeriodicalId":283,"journal":{"name":"Composites Science and Technology","volume":"261 ","pages":"Article 111021"},"PeriodicalIF":8.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1016/j.compscitech.2024.111017
Xinyi Song , Jin Zhou , Jun Wang , Longteng Bai , Xiaohui Yang , Jie Xue , Di Zhang , Shenghao Zhang , Xuefeng Chen , Zhongwei Guan , Wesley J. Cantwell
This study investigates the influence of off-axis tensile loading (0°, 45°, 60° and 90°) on the mechanical behavior of 3D braided composites. Here, digital image correlation is utilized to characterize the full-field deformation and strain distribution in the composites. Scanning electron microscope and micro-computed tomography techniques are also employed to study the deformation and damage mechanisms in the fractured specimens. An off-axis stiffness prediction model for 3D braided composites is proposed, and a finite element model of braided composites containing porosity is established. A user-defined material subroutine is also developed to implement the damage model as a function of off-axis loading angle. The experimental and simulation results demonstrate that the application of off-axis loading causes significant variations in the spatial orientation angle (γ, φ) of the yarn. This phenomenon gives rise to two distinct stages in which the modulus of the composite initially increases, followed by a subsequent decrease. Furthermore, the dominant failure mechanisms in these on-axis samples are found to be yarn breakage and matrix cracking. Also, matrix cracks and filaments pull-out are observed in the off-axis samples.
{"title":"Multi-scale characterisation and damage analysis of 3D braided composites under off-axis tensile loading","authors":"Xinyi Song , Jin Zhou , Jun Wang , Longteng Bai , Xiaohui Yang , Jie Xue , Di Zhang , Shenghao Zhang , Xuefeng Chen , Zhongwei Guan , Wesley J. Cantwell","doi":"10.1016/j.compscitech.2024.111017","DOIUrl":"10.1016/j.compscitech.2024.111017","url":null,"abstract":"<div><div>This study investigates the influence of off-axis tensile loading (0°, 45°, 60° and 90°) on the mechanical behavior of 3D braided composites. Here, digital image correlation is utilized to characterize the full-field deformation and strain distribution in the composites. Scanning electron microscope and micro-computed tomography techniques are also employed to study the deformation and damage mechanisms in the fractured specimens. An off-axis stiffness prediction model for 3D braided composites is proposed, and a finite element model of braided composites containing porosity is established. A user-defined material subroutine is also developed to implement the damage model as a function of off-axis loading angle. The experimental and simulation results demonstrate that the application of off-axis loading causes significant variations in the spatial orientation angle <em>(γ, φ)</em> of the yarn. This phenomenon gives rise to two distinct stages in which the modulus of the composite initially increases, followed by a subsequent decrease. Furthermore, the dominant failure mechanisms in these on-axis samples are found to be yarn breakage and matrix cracking. Also, matrix cracks and filaments pull-out are observed in the off-axis samples.</div></div>","PeriodicalId":283,"journal":{"name":"Composites Science and Technology","volume":"261 ","pages":"Article 111017"},"PeriodicalIF":8.3,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1016/j.compscitech.2024.111019
Guowei Xia , Jun Xie , Yanze Song , Qijun Duan , Yuyao Zhong , Qing Xie
Glass fiber reinforced epoxy resin composite insulating material (GFRP) deteriorates seriously due to moisture, under the exposure to long-term high humidity and high-temperature environments. This affects the stability and safety of power equipment operation. In this work, the plasma method and 1H, 1H, 2H, 2H-perfluorodecyltrimethoxysilane (AFS) were used to prepare fluorinated nano-filler (SiO2), and then a functional layer was prepared by fluorinated nano-filler and water-based epoxy resin. The water-based epoxy resin, as the carrier, fixed fluorinated SiO2 (FSiO2) on the surface of glass fiber (GF), and the effect on the insulation degradation characteristics of GFRP in humid and hot environments is studied. The results show that the FSiO2 functional layer increases the breakdown field strength of GFRP by 16 %, effectively inhibiting the insulation degradation. In terms of water inhibition, the FSiO2 functional layer enhances the hydrophobicity of GFRP and reduces the saturated moisture absorption effectively. The water contact angle increases from 101.2° to 130.6°, with an increase rate of about 30 %. Molecular dynamics simulation results show that the highly electronegative fluorine element improves the electrical insulation performance of GFRP and weakens the influence of humid and hot environments on the insulation performance. In addition, the FSiO2 particles could occupy the free volume of GFRP, and inhibit the free diffusion of water molecules. This reduces the destructive effect of water molecules on the material. This study provides a new research idea for inhibiting the dampness deterioration of GFRP insulation and prolonging its service life in harsh environments.
{"title":"Inhibited the dampness deterioration of GFRP insulation by depositing DBD/AFS co-fluorinated nano-SiO2 functional layer on the GF surface","authors":"Guowei Xia , Jun Xie , Yanze Song , Qijun Duan , Yuyao Zhong , Qing Xie","doi":"10.1016/j.compscitech.2024.111019","DOIUrl":"10.1016/j.compscitech.2024.111019","url":null,"abstract":"<div><div>Glass fiber reinforced epoxy resin composite insulating material (GFRP) deteriorates seriously due to moisture, under the exposure to long-term high humidity and high-temperature environments. This affects the stability and safety of power equipment operation. In this work, the plasma method and 1H, 1H, 2H, 2H-perfluorodecyltrimethoxysilane (AFS) were used to prepare fluorinated nano-filler (SiO<sub>2</sub>), and then a functional layer was prepared by fluorinated nano-filler and water-based epoxy resin. The water-based epoxy resin, as the carrier, fixed fluorinated SiO<sub>2</sub> (FSiO<sub>2</sub>) on the surface of glass fiber (GF), and the effect on the insulation degradation characteristics of GFRP in humid and hot environments is studied. The results show that the FSiO<sub>2</sub> functional layer increases the breakdown field strength of GFRP by 16 %, effectively inhibiting the insulation degradation. In terms of water inhibition, the FSiO<sub>2</sub> functional layer enhances the hydrophobicity of GFRP and reduces the saturated moisture absorption effectively. The water contact angle increases from 101.2° to 130.6°, with an increase rate of about 30 %. Molecular dynamics simulation results show that the highly electronegative fluorine element improves the electrical insulation performance of GFRP and weakens the influence of humid and hot environments on the insulation performance. In addition, the FSiO<sub>2</sub> particles could occupy the free volume of GFRP, and inhibit the free diffusion of water molecules. This reduces the destructive effect of water molecules on the material. This study provides a new research idea for inhibiting the dampness deterioration of GFRP insulation and prolonging its service life in harsh environments.</div></div>","PeriodicalId":283,"journal":{"name":"Composites Science and Technology","volume":"261 ","pages":"Article 111019"},"PeriodicalIF":8.3,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1016/j.compscitech.2024.111018
Minggong Yu, Zhangheng Wang, Xiawang Jiang, Di Wang, Ling Song, Shan Zhao, Jingyi Liu, Delin Sun
Bamboo is a green and sustainable structural material. A new bamboo honeycomb sandwich material (BHSM) was designed and prepared with the bamboo integrated material as panel and the hexagonal bamboo honeycomb core (HBHC) as core layer, and its in-plane compression properties is analyzed using analytical approach, finite element method and response surface method and verified experimentally. The results show that better in-plane compression properties are achieved when the ρ∗/ρ of HBHC of BHSM is higher than 0.155. The optimum compressive properties were achieved when the ρ∗/ρ of HBHC was 0.25, the tf/T was 0.24, and the H/L was 0.19. Under this condition, the stress of the BHSM was 12.62 MPa, which was in error with the prediction model of 9.17 %. Furthermore, the in-plane compression properties of BHSM at optimal structural parameters were better than those of some metals and alloys, and it was 2–5 times that of ordinary carbon fiber polymers and their reinforcements. This work shows that BHSM is a promising green, sustainable, lightweight and high-strength structural material. BHSM can be used in areas such as construction materials, packaging materials and furniture products.
{"title":"In-plane compression properties and parameters optimization of a lightweight and high-strength bamboo honeycomb sandwich material","authors":"Minggong Yu, Zhangheng Wang, Xiawang Jiang, Di Wang, Ling Song, Shan Zhao, Jingyi Liu, Delin Sun","doi":"10.1016/j.compscitech.2024.111018","DOIUrl":"10.1016/j.compscitech.2024.111018","url":null,"abstract":"<div><div>Bamboo is a green and sustainable structural material. A new bamboo honeycomb sandwich material (BHSM) was designed and prepared with the bamboo integrated material as panel and the hexagonal bamboo honeycomb core (HBHC) as core layer, and its in-plane compression properties is analyzed using analytical approach, finite element method and response surface method and verified experimentally. The results show that better in-plane compression properties are achieved when the <em>ρ</em>∗/<em>ρ</em> of HBHC of BHSM is higher than 0.155. The optimum compressive properties were achieved when the <em>ρ</em>∗/<em>ρ</em> of HBHC was 0.25, the <em>t</em><sub><em>f</em></sub>/<em>T</em> was 0.24, and the <em>H</em>/<em>L</em> was 0.19. Under this condition, the stress of the BHSM was 12.62 MPa, which was in error with the prediction model of 9.17 %. Furthermore, the in-plane compression properties of BHSM at optimal structural parameters were better than those of some metals and alloys, and it was 2–5 times that of ordinary carbon fiber polymers and their reinforcements. This work shows that BHSM is a promising green, sustainable, lightweight and high-strength structural material. BHSM can be used in areas such as construction materials, packaging materials and furniture products.</div></div>","PeriodicalId":283,"journal":{"name":"Composites Science and Technology","volume":"261 ","pages":"Article 111018"},"PeriodicalIF":8.3,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1016/j.compscitech.2024.111016
Xiangyu Mei , Yujie You , Kehan Qu , Kun Peng , Feiyan Wu , Min Li , Kui Li , Fengning Liu , Yaqin Fu , Yinsong Si
Polyimide (PI) with ultralow dielectric constant (Dk) and dielectric loss (Df) is highly desired for high-frequency and high-speed electromagnetic communications. Herein, PIfm/PI composites with excellent dielectric and hydrophobic properties were successfully prepared by impregnating an electrospun PI nanofiber membrane (PIfm) with polyamic acid (PAA) solutions prior to re-imidization process. Evenly distribution of impregnated PAA in the PIfm endows the imitated PI matrix to bind with PI fibers tightly. The abundant internal stress at the interfaces of PI nanofibers and PI matrix results in a higher chain packing density, which greatly inhabits dipole polarization in the PIfm/PI composites. Specifically, the PIfm/PI-15% composite demonstrates an average ultralow Dk of 1.756 and Df of 0.004 in high-frequency range (8.2–12.4 GHz), together with a quite high dielectric breakdown strength reaching 226.47 kV mm−1 and sufficient tensile strength of 40.3 MPa. The Td5% is higher than 560 °C while keeping the coefficient of linear thermal expansion lower than 50 ppm °C−1. Moreover, the PIfm/PI composites possess a hydrophobic property with contact angle above 108.0°, ensuring the dielectric stability even in a high-temperature or humid environment. The obtained fluorine-free PIfm/PI composites with excellent dielectric and hydrophobic properties via electrospinning-impregnation method will greatly boost the advancement of PI nanofiber composites in high-frequency applications.
{"title":"Electrospinning-impregnation: Producing hydrophobic polyimide composites with superior dielectric properties","authors":"Xiangyu Mei , Yujie You , Kehan Qu , Kun Peng , Feiyan Wu , Min Li , Kui Li , Fengning Liu , Yaqin Fu , Yinsong Si","doi":"10.1016/j.compscitech.2024.111016","DOIUrl":"10.1016/j.compscitech.2024.111016","url":null,"abstract":"<div><div>Polyimide (PI) with ultralow dielectric constant (<em>D</em><sub>k</sub>) and dielectric loss (<em>D</em><sub>f</sub>) is highly desired for high-frequency and high-speed electromagnetic communications. Herein, PI<sub>fm</sub>/PI composites with excellent dielectric and hydrophobic properties were successfully prepared by impregnating an electrospun PI nanofiber membrane (PI<sub>fm</sub>) with polyamic acid (PAA) solutions prior to re-imidization process. Evenly distribution of impregnated PAA in the PI<sub>fm</sub> endows the imitated PI matrix to bind with PI fibers tightly. The abundant internal stress at the interfaces of PI nanofibers and PI matrix results in a higher chain packing density, which greatly inhabits dipole polarization in the PI<sub>fm</sub>/PI composites. Specifically, the PI<sub>fm</sub>/PI-15% composite demonstrates an average ultralow <em>D</em><sub>k</sub> of 1.756 and <em>D</em><sub>f</sub> of 0.004 in high-frequency range (8.2–12.4 GHz), together with a quite high dielectric breakdown strength reaching 226.47 kV mm<sup>−1</sup> and sufficient tensile strength of 40.3 MPa. The <em>T</em><sub>d5%</sub> is higher than 560 °C while keeping the coefficient of linear thermal expansion lower than 50 ppm °C<sup>−1</sup>. Moreover, the PI<sub>fm</sub>/PI composites possess a hydrophobic property with contact angle above 108.0°, ensuring the dielectric stability even in a high-temperature or humid environment. The obtained fluorine-free PI<sub>fm</sub>/PI composites with excellent dielectric and hydrophobic properties via electrospinning-impregnation method will greatly boost the advancement of PI nanofiber composites in high-frequency applications.</div></div>","PeriodicalId":283,"journal":{"name":"Composites Science and Technology","volume":"261 ","pages":"Article 111016"},"PeriodicalIF":8.3,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1016/j.compscitech.2024.111005
Wenmu Yang , Jason Tan , Jiawei Wang , Wenkai Chang , Mohammad S. Islam , Zhao Sha , Cheng Wang , Bo Lin , Jin Zhang , Guan Heng Yeoh , Cyrille Boyer , Chun H. Wang
Existing methods of incorporating flame-retardant fillers to improve the fire resistance of epoxy-matrix based carbon fibre composites often significantly reduce their mechanical properties. To address this issue, this study introduces a novel method for synthesizing nano-sized ammonium polyphosphate (APP) particles by reacting them with amine-containing hardener and applying probe sonication, resulting in nano-sized APP particles (SHF-APP). This treatment reduces the particle size from 14 μm to 0.12 μm. A systematic investigation of the impact of particle size and the hardener treatment reveals that the SHF-APP nanoparticles can simultaneously improve flame-retardancy and mechanical properties of the composites. The concurrent improvements in fire resistance and mechanical properties highlight the significant potential of this novel approach, enabling carbon fibre reinforced epoxy composites to withstand extreme environments and meet stringent fire safety standards while maintaining high mechanical and fracture properties, a feat previously unattainable with conventional methods.
{"title":"Enhancing mechanical and flame retardant properties of carbon fibre epoxy composites with functionalised ammonium polyphosphate nanoparticles","authors":"Wenmu Yang , Jason Tan , Jiawei Wang , Wenkai Chang , Mohammad S. Islam , Zhao Sha , Cheng Wang , Bo Lin , Jin Zhang , Guan Heng Yeoh , Cyrille Boyer , Chun H. Wang","doi":"10.1016/j.compscitech.2024.111005","DOIUrl":"10.1016/j.compscitech.2024.111005","url":null,"abstract":"<div><div>Existing methods of incorporating flame-retardant fillers to improve the fire resistance of epoxy-matrix based carbon fibre composites often significantly reduce their mechanical properties. To address this issue, this study introduces a novel method for synthesizing nano-sized ammonium polyphosphate (APP) particles by reacting them with amine-containing hardener and applying probe sonication, resulting in nano-sized APP particles (SHF-APP). This treatment reduces the particle size from 14 μm to 0.12 μm. A systematic investigation of the impact of particle size and the hardener treatment reveals that the SHF-APP nanoparticles can simultaneously improve flame-retardancy and mechanical properties of the composites. The concurrent improvements in fire resistance and mechanical properties highlight the significant potential of this novel approach, enabling carbon fibre reinforced epoxy composites to withstand extreme environments and meet stringent fire safety standards while maintaining high mechanical and fracture properties, a feat previously unattainable with conventional methods.</div></div>","PeriodicalId":283,"journal":{"name":"Composites Science and Technology","volume":"261 ","pages":"Article 111005"},"PeriodicalIF":8.3,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-15DOI: 10.1016/j.compscitech.2024.111014
Mingming Yu , Mujaheed Halliru Saad , Xiangyu Lin , Fuhao Dong , Xu Fan , Xu Xu , He Liu , Zhanqian Song
Incorporating dynamic covalent bonds into polyurethane (PU) elastomers contributes to exceptional self-healing and recyclable properties. However, further applications are seriously limited due to unsatisfying mechanical characteristics. Herein, a self-healing and ultra-robust nanocomposite elastomer is presented here that consists of polyurethane matrix and cellulose nanocrystals through the synergistic gradient hydrogen bonds and strain-induced reversible crystallization effect. Multiple dynamic hydrogen bonds formed between cellulose nanocrystals (CNC) and polyurethane (PHHD) together with the strain-induced reversible crystallized physical network facilitate excellent mechanical properties while maintaining favorable self-healing ability. The introduction of cellulose nanocrystals significantly enhanced the binding energy of the nanocomposite polyurethane elastomer system, exhibiting an increase of 204.32 kJ/mol. Consequently, nanocomposite elastomers display a remarkable tensile strength (up to 50.1 MPa), ultra-high toughness (441.6 MJ/m3), and excellent fracture energy (214.5 kJ/m2) Furthermore, the result found that the introduction of cellulose nanocrystals can reduce the reaction activation energy and obtain nanocomposite elastomers with highly efficient self-healing (93.9 %). The innovative approach is expected to facilitate the development of high-strength, tough, and exceptional self-healing elastomers in academia and industry.
{"title":"Synergistic multiple hydrogen bonds and reversible crystallization effect enable ultra-tough, self-healing, and recyclable cellulose-enhanced elastomer","authors":"Mingming Yu , Mujaheed Halliru Saad , Xiangyu Lin , Fuhao Dong , Xu Fan , Xu Xu , He Liu , Zhanqian Song","doi":"10.1016/j.compscitech.2024.111014","DOIUrl":"10.1016/j.compscitech.2024.111014","url":null,"abstract":"<div><div>Incorporating dynamic covalent bonds into polyurethane (PU) elastomers contributes to exceptional self-healing and recyclable properties. However, further applications are seriously limited due to unsatisfying mechanical characteristics. Herein, a self-healing and ultra-robust nanocomposite elastomer is presented here that consists of polyurethane matrix and cellulose nanocrystals through the synergistic gradient hydrogen bonds and strain-induced reversible crystallization effect. Multiple dynamic hydrogen bonds formed between cellulose nanocrystals (CNC) and polyurethane (PHHD) together with the strain-induced reversible crystallized physical network facilitate excellent mechanical properties while maintaining favorable self-healing ability. The introduction of cellulose nanocrystals significantly enhanced the binding energy of the nanocomposite polyurethane elastomer system, exhibiting an increase of 204.32 kJ/mol. Consequently, nanocomposite elastomers display a remarkable tensile strength (up to 50.1 MPa), ultra-high toughness (441.6 MJ/m<sup>3</sup>), and excellent fracture energy (214.5 kJ/m<sup>2</sup>) Furthermore, the result found that the introduction of cellulose nanocrystals can reduce the reaction activation energy and obtain nanocomposite elastomers with highly efficient self-healing (93.9 %). The innovative approach is expected to facilitate the development of high-strength, tough, and exceptional self-healing elastomers in academia and industry.</div></div>","PeriodicalId":283,"journal":{"name":"Composites Science and Technology","volume":"261 ","pages":"Article 111014"},"PeriodicalIF":8.3,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号