Crystallinity is important to the properties of a semi-crystalline fluoropolymer, such as solubility, mechanical property, bonding strength, etc. This study extended the use of 19F Low-Field Nuclear Magnetic Resonance (19F LF-NMR) to the measurement of crystallinity in the semi-crystalline fluoropolymer F2314, which is the copolymer of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE) with a molar ratio of 1:4 and commonly used as binder in polymer-bonded explosives (PBXs). Based on the difference between spin-spin relaxometry of the 19F in crystalline region and in amorphous region, the crystallinity of F2314 can be qualitatively characterized. The obtained crystallinity exhibited a positive correlation to the time duration of thermal treatment, which is in consistent to the result of Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD). Moreover, 19F LF-NMR detected the slight decrease in segmental motion of crystalline region with the increase of crystallinity, and on-line monitored the evolution of segmental motion during heating. This study not only demonstrates the practicality and reliability of 19F LF-NMR in quantification of crystallinity, but also laid the foundation for in-situ characterization of fluoropolymers in PBXs in future work.
{"title":"Quantitative characterization of crystallinity in semi-crystalline fluoropolymer through 19F LF-NMR relaxometry","authors":"Zhangyu Wu , Xianru He , Chunhua Zhu , Huaisong Yong , Xueyan Zhao","doi":"10.1016/j.polymertesting.2024.108654","DOIUrl":"10.1016/j.polymertesting.2024.108654","url":null,"abstract":"<div><div>Crystallinity is important to the properties of a semi-crystalline fluoropolymer, such as solubility, mechanical property, bonding strength, etc. This study extended the use of <sup>19</sup>F Low-Field Nuclear Magnetic Resonance (<sup>19</sup>F LF-NMR) to the measurement of crystallinity in the semi-crystalline fluoropolymer F2314, which is the copolymer of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE) with a molar ratio of 1:4 and commonly used as binder in polymer-bonded explosives (PBXs). Based on the difference between spin-spin relaxometry of the <sup>19</sup>F in crystalline region and in amorphous region, the crystallinity of F2314 can be qualitatively characterized. The obtained crystallinity exhibited a positive correlation to the time duration of thermal treatment, which is in consistent to the result of Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD). Moreover, <sup>19</sup>F LF-NMR detected the slight decrease in segmental motion of crystalline region with the increase of crystallinity, and on-line monitored the evolution of segmental motion during heating. This study not only demonstrates the practicality and reliability of <sup>19</sup>F LF-NMR in quantification of crystallinity, but also laid the foundation for in-situ characterization of fluoropolymers in PBXs in future work.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"141 ","pages":"Article 108654"},"PeriodicalIF":5.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-01DOI: 10.1016/j.polymertesting.2024.108652
Yeongu Choi , Minhyeok Kim , Hongyun So
Composite-based temperature sensors utilizing the negative temperature coefficient (NTC) effect have gained significant attention across various fields, particularly in healthcare. However, the development of innovative, highly linear, and high-performance NTC-based temperature sensors remains a challenge. In this study, we developed a composite temperature sensor comprising thermoplastic polyurethane (TPU), single-walled carbon nanotubes (SWCNTs), and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). A series of performance tests demonstrated that the TPU/SWCNT/PEDOT:PSS (TSP) composite effectively monitors temperature variations with both linearity and superior performance, attributed to the synergistic NTC effects of SWCNTs and PEDOT:PSS. This flexible temperature sensor retained its sensing functionality after repeated cycles of temperature fluctuations and multiple bending tests. Moreover, due to the unique properties of CNTs, the TSP sensor exhibited photothermal responses, showing highly sensitive resistance changes upon exposure to infrared radiation. The TSP sensor proved to be effective for various practical applications, including biosignal monitoring through thermal detection, temperature tracking during phone charging, and accurate temperature sensing on curved surfaces. Additionally, non-contact heat detection can be reliably performed regardless of whether tensile stress is applied. These findings underscore the immense potential of TSP sensors for future use in wearable healthcare technologies.
{"title":"Negative temperature coefficient effect of TPU/SWCNT/PEDOT:PSS polymer matrices for wearable temperature sensors","authors":"Yeongu Choi , Minhyeok Kim , Hongyun So","doi":"10.1016/j.polymertesting.2024.108652","DOIUrl":"10.1016/j.polymertesting.2024.108652","url":null,"abstract":"<div><div>Composite-based temperature sensors utilizing the negative temperature coefficient (NTC) effect have gained significant attention across various fields, particularly in healthcare. However, the development of innovative, highly linear, and high-performance NTC-based temperature sensors remains a challenge. In this study, we developed a composite temperature sensor comprising thermoplastic polyurethane (TPU), single-walled carbon nanotubes (SWCNTs), and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). A series of performance tests demonstrated that the TPU/SWCNT/PEDOT:PSS (TSP) composite effectively monitors temperature variations with both linearity and superior performance, attributed to the synergistic NTC effects of SWCNTs and PEDOT:PSS. This flexible temperature sensor retained its sensing functionality after repeated cycles of temperature fluctuations and multiple bending tests. Moreover, due to the unique properties of CNTs, the TSP sensor exhibited photothermal responses, showing highly sensitive resistance changes upon exposure to infrared radiation. The TSP sensor proved to be effective for various practical applications, including biosignal monitoring through thermal detection, temperature tracking during phone charging, and accurate temperature sensing on curved surfaces. Additionally, non-contact heat detection can be reliably performed regardless of whether tensile stress is applied. These findings underscore the immense potential of TSP sensors for future use in wearable healthcare technologies.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"141 ","pages":"Article 108652"},"PeriodicalIF":5.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-01DOI: 10.1016/j.polymertesting.2024.108646
Keming Zhang, Cong Yu, Chunhai Chen
In the automotive and aerospace industries, carbon fiber is widely used in structures such as chassis and wings due to its lightweight and excellent mechanical properties, and the residual stresses are crucial for product design. In this paper, six kinds of carbon fiber laminates with different layup directions are investigated by using the integral method, and the calibration coefficient matrix is numerically solved by using ABAQUS finite element software, and the effects of laminate direction and incremental step on the three-direction residual stresses are experimentally analyzed. The residual stresses in different oriented layers were predicted by classical lamination theory (CLT), and the longitudinal, transverse and in-plane shear stresses were compared by combining incremental drilling experiments with calibration factors. The results showed that the ply with laminate had the best performance,the difference between theoretical and experimental values for was . The maximum measurement was , with a maximum percentage error of 25.3%. The maximum difference for was . These findings indicate that the method is more accurate in predicting the residual stresses in the first four layers of composite material. This provides important theoretical and experimental support for the optimal design of composites.
{"title":"Measurement and analysis of residual stress of multilayer carbon fiber laminate based on incremental drilling method","authors":"Keming Zhang, Cong Yu, Chunhai Chen","doi":"10.1016/j.polymertesting.2024.108646","DOIUrl":"10.1016/j.polymertesting.2024.108646","url":null,"abstract":"<div><div>In the automotive and aerospace industries, carbon fiber is widely used in structures such as chassis and wings due to its lightweight and excellent mechanical properties, and the residual stresses are crucial for product design. In this paper, six kinds of carbon fiber laminates with different layup directions are investigated by using the integral method, and the calibration coefficient matrix is numerically solved by using ABAQUS finite element software, and the effects of laminate direction and incremental step on the three-direction residual stresses are experimentally analyzed. The residual stresses in different oriented layers were predicted by classical lamination theory (CLT), and the longitudinal, transverse and in-plane shear stresses were compared by combining incremental drilling experiments with calibration factors. The results showed that the ply with <span><math><mrow><mo>[</mo><mn>45</mn><mo>/</mo><mn>90</mn><mo>/</mo><mo>−</mo><mn>45</mn><mo>/</mo><mn>0</mn><mo>/</mo><mn>45</mn><mo>/</mo><mn>90</mn><mo>/</mo><mo>−</mo><mn>45</mn><mo>/</mo><mn>0</mn><mo>]</mo></mrow></math></span> laminate had the best performance,the difference between theoretical and experimental values for <span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>x</mi></mrow></msub></math></span> was <span><math><mrow><mn>0</mn><mo>.</mo><mn>421</mn><mspace></mspace><mi>MPa</mi></mrow></math></span>. The maximum <span><math><msub><mrow><mi>τ</mi></mrow><mrow><mi>x</mi><mi>y</mi></mrow></msub></math></span> measurement was <span><math><mrow><mn>1</mn><mo>.</mo><mn>7103</mn><mspace></mspace><mi>MPa</mi></mrow></math></span>, with a maximum percentage error of 25.3%. The maximum difference for <span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>y</mi></mrow></msub></math></span> was <span><math><mrow><mn>0</mn><mo>.</mo><mn>7306</mn><mspace></mspace><mi>MPa</mi></mrow></math></span>. These findings indicate that the method is more accurate in predicting the residual stresses in the first four layers of composite material. This provides important theoretical and experimental support for the optimal design of composites.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"141 ","pages":"Article 108646"},"PeriodicalIF":5.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-01DOI: 10.1016/j.polymertesting.2024.108648
Yasser Zare , Muhammad Tajammal Munir , Kyong Yop Rhee , Soo-Jin Park
The existing models for the electrical conductivity of polymer composites with carbon nanofiber (CNF) called as PCNFs are incomplete, thereby limiting their optimization. In this study, the Hui-Shia model is simplified and advanced to accurately foresee the PCNF conductivity by incorporating the main features of CNFs, interphase, and tunnels. The volume fraction of the CNF/interphase network is derived based on the onset of percolation and effective CNF content, while the total conductivity of CNF and tunnels is expressed through tunneling properties. The developed model is evaluated using experimental data from various PCNF systems and through parametric analyses. Theoretical and experimental results demonstrate good agreement, validating the developed model. An insulative PCNF is observed at a CNF radius (R) greater than 90 nm and an interphase depth (t) less than 11 nm. Conversely, the maximum conductivity of 1.5 S/m is achieved with the thinnest CNFs (R = 40 nm) and the thickest interphase (t = 40 nm). Furthermore, very small contact diameters (d less than 17 nm) do not result in significant conductivity; however, the maximum conductivity of 0.27 S/m is observed with the widest tunnels (d = 40 nm) and the highest CNF aspect ratio of 1000.
{"title":"Optimizing conductive properties of polymer carbon nanofiber composites: Insights from an extended Hui-Shia model","authors":"Yasser Zare , Muhammad Tajammal Munir , Kyong Yop Rhee , Soo-Jin Park","doi":"10.1016/j.polymertesting.2024.108648","DOIUrl":"10.1016/j.polymertesting.2024.108648","url":null,"abstract":"<div><div>The existing models for the electrical conductivity of polymer composites with carbon nanofiber (CNF) called as PCNFs are incomplete, thereby limiting their optimization. In this study, the Hui-Shia model is simplified and advanced to accurately foresee the PCNF conductivity by incorporating the main features of CNFs, interphase, and tunnels. The volume fraction of the CNF/interphase network is derived based on the onset of percolation and effective CNF content, while the total conductivity of CNF and tunnels is expressed through tunneling properties. The developed model is evaluated using experimental data from various PCNF systems and through parametric analyses. Theoretical and experimental results demonstrate good agreement, validating the developed model. An insulative PCNF is observed at a CNF radius (<em>R</em>) greater than 90 nm and an interphase depth (<em>t</em>) less than 11 nm. Conversely, the maximum conductivity of 1.5 S/m is achieved with the thinnest CNFs (<em>R</em> = 40 nm) and the thickest interphase (<em>t</em> = 40 nm). Furthermore, very small contact diameters (<em>d</em> less than 17 nm) do not result in significant conductivity; however, the maximum conductivity of 0.27 S/m is observed with the widest tunnels (<em>d</em> = 40 nm) and the highest CNF aspect ratio of 1000.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"141 ","pages":"Article 108648"},"PeriodicalIF":5.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-01DOI: 10.1016/j.polymertesting.2024.108653
Daniele Finazzi , Guillem Seychal , Jean-Marie Raquez , Gilles Robert , Karen De Clerck , Lode Daelemans , Wim Van Paepegem
Polyamide-6 (PA6) and short glass fibre-reinforced PA6 (GPA6) are increasingly used in structural automotive parts exposed to harsh conditions, respectively as liner in Type IV hydrogen tanks and under-the-hood components near the engine. Safe design requires understanding of their complex mechanical behaviour under the influence of temperature, moisture, and strain rate. Two models often applied in the literature are the temperature-humidity equivalence and the time-temperature superposition (TTS), however their accuracy to describe the full mechanical response is still unclear. By generating high-quality data, this paper conducts a quantitative study of these models on the mechanical response of injection-moulded PA6 and GPA6 with a very high fibre content (50 wt%). The materials were conditioned either dry or at 50%RH. Dynamic mechanical analysis (DMA) was used to measure the glass transition temperature of dry PA6 and 50%RH PA6, and to construct TTS master curves. Tensile tests were then conducted at different combinations of temperature, moisture, and strain rate. Comparison of the tensile true stress-true strain curves revealed that the proposed models fail to capture the effects of the thermal history, which may cause microstructural modifications as demonstrated with differential scanning calorimetry (DSC). The link between DSC, DMA, and tensile data constitutes a novelty of this work and was possible because all the samples had the same hygro-thermal history. Additionally, self-heating of PA6 causes deviations from the TTS at large strains. The results of this study may help develop more accurate material models, ultimately improving the design of structural automotive parts.
{"title":"Study of the temperature-humidity equivalence and the time-temperature superposition principle in the finite-strain response of polyamide-6 and short glass fibre-reinforced polyamide-6","authors":"Daniele Finazzi , Guillem Seychal , Jean-Marie Raquez , Gilles Robert , Karen De Clerck , Lode Daelemans , Wim Van Paepegem","doi":"10.1016/j.polymertesting.2024.108653","DOIUrl":"10.1016/j.polymertesting.2024.108653","url":null,"abstract":"<div><div>Polyamide-6 (PA6) and short glass fibre-reinforced PA6 (GPA6) are increasingly used in structural automotive parts exposed to harsh conditions, respectively as liner in Type IV hydrogen tanks and under-the-hood components near the engine. Safe design requires understanding of their complex mechanical behaviour under the influence of temperature, moisture, and strain rate. Two models often applied in the literature are the temperature-humidity equivalence and the time-temperature superposition (TTS), however their accuracy to describe the full mechanical response is still unclear. By generating high-quality data, this paper conducts a quantitative study of these models on the mechanical response of injection-moulded PA6 and GPA6 with a very high fibre content (50 wt%). The materials were conditioned either dry or at 50%RH. Dynamic mechanical analysis (DMA) was used to measure the glass transition temperature of dry PA6 and 50%RH PA6, and to construct TTS master curves. Tensile tests were then conducted at different combinations of temperature, moisture, and strain rate. Comparison of the tensile true stress-true strain curves revealed that the proposed models fail to capture the effects of the thermal history, which may cause microstructural modifications as demonstrated with differential scanning calorimetry (DSC). The link between DSC, DMA, and tensile data constitutes a novelty of this work and was possible because all the samples had the same hygro-thermal history. Additionally, self-heating of PA6 causes deviations from the TTS at large strains. The results of this study may help develop more accurate material models, ultimately improving the design of structural automotive parts.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"141 ","pages":"Article 108653"},"PeriodicalIF":5.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-12-01DOI: 10.1016/j.polymertesting.2024.108650
Wenjun Zhou, Bo Liu, Meng Zhao, Xuanjun Wang
The submerged cavitation water jet (SCWJ) is a promising technology for removing solid propellant from old solid rocket engines and recycling them. In this study, the feasibility of using SCWJ to break solid propellant is investigated. The structure of the cavitation cloud was captured by a high-speed camera and then analyzed using the Proper Orthogonal Decomposition (POD) and Frame Difference Method (FDM) method for exploring the unsteady characteristic of SCWJ, the HTPB propellant erosion experiments were performed, and the relationship of the SCWJ unsteady characteristic and the erosion results on HTPB propellant was analyzed. The results show that the SCWJ develops in the flow field including inception, development, shedding, and collapse stages, the maximum density of cavitation cloud changes exponentially, and the cavitation cloud length grows as the cavitation numbers increase. Lower cavitation number is always beneficial to high penetration rate and low energy consumption when erosion on the HTPB propellant. When the erosion time of 120 s, in high cavitation number under the least amount of energy consumed, the unit energy consumption minimum. The mass loss curve is double peak, the first peak is caused by water jet effect, standoff distance is located on the stage of development, the formation of erosion pit diameter is small, the depth is larger, the second peak is caused by cavitation effect, and its standoff distance is located on the shedding phase, forming the erosion pit diameter is bigger, the depth is shallow. The optimum standoff distance for the cavitation effect for the cavitation numbers 0.0135, 0.0081, 0.0058 and 0.0045 is 35 mm, 50 mm, 60 mm and 70 mm in order, and the mass loss rate of HTPB propellant is 90 mg s−1, 200 mg s−1, 277 mg s−1 and 521 mg s−1, respectively. At best cavitation effect standoff distance, cavitation number by 2 times, mass loss rate can increase 3 times. The matrix brittle fractures occur when the SCWJ strikes the HTPB propellant at a high strain rate. Besides, the erosion mechanism of HTPB propellant is discussed.
{"title":"An experimental study on the erosion of solid propellant by cavitation water jet in submerged environment","authors":"Wenjun Zhou, Bo Liu, Meng Zhao, Xuanjun Wang","doi":"10.1016/j.polymertesting.2024.108650","DOIUrl":"10.1016/j.polymertesting.2024.108650","url":null,"abstract":"<div><div>The submerged cavitation water jet (SCWJ) is a promising technology for removing solid propellant from old solid rocket engines and recycling them. In this study, the feasibility of using SCWJ to break solid propellant is investigated. The structure of the cavitation cloud was captured by a high-speed camera and then analyzed using the Proper Orthogonal Decomposition (POD) and Frame Difference Method (FDM) method for exploring the unsteady characteristic of SCWJ, the HTPB propellant erosion experiments were performed, and the relationship of the SCWJ unsteady characteristic and the erosion results on HTPB propellant was analyzed. The results show that the SCWJ develops in the flow field including inception, development, shedding, and collapse stages, the maximum density of cavitation cloud changes exponentially, and the cavitation cloud length grows as the cavitation numbers increase. Lower cavitation number is always beneficial to high penetration rate and low energy consumption when erosion on the HTPB propellant. When the erosion time of 120 s, in high cavitation number under the least amount of energy consumed, the unit energy consumption minimum. The mass loss curve is double peak, the first peak is caused by water jet effect, standoff distance is located on the stage of development, the formation of erosion pit diameter is small, the depth is larger, the second peak is caused by cavitation effect, and its standoff distance is located on the shedding phase, forming the erosion pit diameter is bigger, the depth is shallow. The optimum standoff distance for the cavitation effect for the cavitation numbers 0.0135, 0.0081, 0.0058 and 0.0045 is 35 mm, 50 mm, 60 mm and 70 mm in order, and the mass loss rate of HTPB propellant is 90 mg s<sup>−1</sup>, 200 mg s<sup>−1</sup>, 277 mg s<sup>−1</sup> and 521 mg s<sup>−1</sup>, respectively. At best cavitation effect standoff distance, cavitation number by 2 times, mass loss rate can increase 3 times. The matrix brittle fractures occur when the SCWJ strikes the HTPB propellant at a high strain rate. Besides, the erosion mechanism of HTPB propellant is discussed.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"141 ","pages":"Article 108650"},"PeriodicalIF":5.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-22DOI: 10.1016/j.polymertesting.2024.108651
Khulaif Alshammari, Alhulw H. Alshammari
This study reports the synthesis and characterization of Cr₂O₃/g-C₃N₄ doped PVA nanocomposite membranes using a solution casting method for potential optoelectronic applications. The successful incorporation of Cr₂O₃ and g-C₃N₄ into the PVA matrix was confirmed through various analytical techniques, comprising FTIR, XRD, SEM, EDX, and XPS. The addition of Cr₂O₃/g-C₃N₄ resulted in enhanced thermal stability, as demonstrated by an increase in decomposition temperature by 25–38 °C. Optical analysis revealed a reduction in both direct and indirect band gaps, from 5.41 eV to 4.85 eV and 5.18 eV–4.65 eV, respectively, indicating modifications in the electronic structure of the composite. This enhancement in optical and thermal properties can be linked to the robust interfacial interactions between the nanofillers and the PVA matrix. The novelty of this research lies in the synergistic effect of Cr₂O₃ and g-C₃N₄, which not only improves the composite's stability and optical properties but also provides a pathway for the development of advanced materials with tunable electronic characteristics for optoelectronic devices. The results of this study contribute to the growing need for environmentally friendly, high-performance materials that can be utilized in a variety of implementations, such as sensors and flexible electronics, thereby having a positive impact on technology development and societal progress.
{"title":"Synthesis of Cr2O3/C3N4 doped PVA polymer membranes for optoelectronic applications","authors":"Khulaif Alshammari, Alhulw H. Alshammari","doi":"10.1016/j.polymertesting.2024.108651","DOIUrl":"10.1016/j.polymertesting.2024.108651","url":null,"abstract":"<div><div>This study reports the synthesis and characterization of Cr₂O₃/g-C₃N₄ doped PVA nanocomposite membranes using a solution casting method for potential optoelectronic applications. The successful incorporation of Cr₂O₃ and g-C₃N₄ into the PVA matrix was confirmed through various analytical techniques, comprising FTIR, XRD, SEM, EDX, and XPS. The addition of Cr₂O₃/g-C₃N₄ resulted in enhanced thermal stability, as demonstrated by an increase in decomposition temperature by 25–38 °C. Optical analysis revealed a reduction in both direct and indirect band gaps, from 5.41 eV to 4.85 eV and 5.18 eV–4.65 eV, respectively, indicating modifications in the electronic structure of the composite. This enhancement in optical and thermal properties can be linked to the robust interfacial interactions between the nanofillers and the PVA matrix. The novelty of this research lies in the synergistic effect of Cr₂O₃ and g-C₃N₄, which not only improves the composite's stability and optical properties but also provides a pathway for the development of advanced materials with tunable electronic characteristics for optoelectronic devices. The results of this study contribute to the growing need for environmentally friendly, high-performance materials that can be utilized in a variety of implementations, such as sensors and flexible electronics, thereby having a positive impact on technology development and societal progress.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"141 ","pages":"Article 108651"},"PeriodicalIF":5.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-22DOI: 10.1016/j.polymertesting.2024.108649
Masoumeh Kianfar , Mir Saeed Seyed Dorraji , Mohammad Hossein Rasoulifard , Alireza Rahimi , Sohrab Rahmani
Herein, a self-healing waterborne polyurethane (WPU) based on a novel visible light-stimulated healing agent from the aromatic Schiff base family (SBWPU) was synthesized. Moreover, this polymer exhibited remarkable mechanical properties, making it an ideal matrix for the preparation of a new nano-composite coating using hexagonal-boron nitride/graphene oxide/nickel oxide (h-BN/GO/NiO) nano-composite for anti-corrosion applications. SBWPU containing 15 wt % of synthesized healing agent (SBWPU-15) demonstrated favorable healing properties (80.03 %) under a visible light lamp after 24 h (at ambient temperature). SBWPU containing 20 % of the healing agent (SBWPU-20) showed high mechanical properties (20.80 MPa) and an increase in its hydrophobic properties. Additionally, its water absorption rate decreased, making it an attractive option as a polymer matrix for anti-corrosion coating applications. The nano-composite coatings (CSBWPU) were formulated by introducing varying amounts of h-BN/GO/NiO into the SBWPU-20. The coatings displayed an increase in contact angle and a decrease in water absorption rate. The electrochemical impedance spectroscopy (EIS) results revealed that the 0.75-CSBWPU, containing 0.75 % nano-composite, had the highest corrosion resistance (1.58 × 1010 Ω cm2) after 90 days of immersion in seawater. This work offers a potentially helpful concept for developing an eco-friendly, secure, uncomplicated accessibility self-healing polymeric system with controllable mechanical features, which are also favorable for designing novel corrosion protection composite coatings.
{"title":"Synthesis and application of Aromatic Schiff base waterborne polyurethane as visible-light triggered self-healing polymer and anticorrosion coating using h-BN/GO/NiO nano-composite","authors":"Masoumeh Kianfar , Mir Saeed Seyed Dorraji , Mohammad Hossein Rasoulifard , Alireza Rahimi , Sohrab Rahmani","doi":"10.1016/j.polymertesting.2024.108649","DOIUrl":"10.1016/j.polymertesting.2024.108649","url":null,"abstract":"<div><div>Herein, a self-healing waterborne polyurethane (WPU) based on a novel visible light-stimulated healing agent from the aromatic Schiff base family (SBWPU) was synthesized. Moreover, this polymer exhibited remarkable mechanical properties, making it an ideal matrix for the preparation of a new nano-composite coating using hexagonal-boron nitride/graphene oxide/nickel oxide (h-BN/GO/NiO) nano-composite for anti-corrosion applications. SBWPU containing 15 wt % of synthesized healing agent (SBWPU-15) demonstrated favorable healing properties (80.03 %) under a visible light lamp after 24 h (at ambient temperature). SBWPU containing 20 % of the healing agent (SBWPU-20) showed high mechanical properties (20.80 MPa) and an increase in its hydrophobic properties. Additionally, its water absorption rate decreased, making it an attractive option as a polymer matrix for anti-corrosion coating applications. The nano-composite coatings (CSBWPU) were formulated by introducing varying amounts of h-BN/GO/NiO into the SBWPU-20. The coatings displayed an increase in contact angle and a decrease in water absorption rate. The electrochemical impedance spectroscopy (EIS) results revealed that the 0.75-CSBWPU, containing 0.75 % nano-composite, had the highest corrosion resistance (1.58 × 10<sup>10</sup> Ω cm<sup>2</sup>) after 90 days of immersion in seawater. This work offers a potentially helpful concept for developing an eco-friendly, secure, uncomplicated accessibility self-healing polymeric system with controllable mechanical features, which are also favorable for designing novel corrosion protection composite coatings.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"141 ","pages":"Article 108649"},"PeriodicalIF":5.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-20DOI: 10.1016/j.polymertesting.2024.108647
Birgit Achleitner , Tobias Huber , Silvia Larisegger , Michael Nelhiebel , Patrick Knaack , Andreas Limbeck
High-performance polymers like polyimides are well known for their outstanding chemical and physical properties and play an important role in high-demanding applications like automotive, aerospace, medical, etc. Polyimide thin films are especially useful in the electronics industry to protect the underlying devices from elevated temperatures, humidity, corrosive gases and high voltages. Therefore, the curing of polyimides has been studied extensively to ensure ideal material properties and new tools and methods for sample characterization are of great interest. Besides conventional techniques like Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA) or Differential Scanning Calorimetry (DSC), Laser Induced Breakdown Spectroscopy (LIBS) has been introduced recently to monitor the imidization reaction of a polyimide thin film. To obtain information about the temporal evolution of the reaction as well as optimize labor- and time-consuming sample preparation, a heating chamber for simultaneous thermal treatment and LIBS measurements (in-situ experiments) was developed and successfully used for imidization studies of self-synthesized polyimides. Besides a general introduction of the chamber design, the results of the in-situ investigation are presented: isothermal studies to gain temporal information about the imidization reaction of a single film and stepwise heating to investigate the influence of the curing temperature. Finally, LIBS depth-profiling revealed depth-resolved information about the imidization degree over the entire film thickness, illustrating one of the great advantages of the LIBS technique.
{"title":"Monitoring the imidization reaction of polyimide thin films using an in-situ LIBS approach","authors":"Birgit Achleitner , Tobias Huber , Silvia Larisegger , Michael Nelhiebel , Patrick Knaack , Andreas Limbeck","doi":"10.1016/j.polymertesting.2024.108647","DOIUrl":"10.1016/j.polymertesting.2024.108647","url":null,"abstract":"<div><div>High-performance polymers like polyimides are well known for their outstanding chemical and physical properties and play an important role in high-demanding applications like automotive, aerospace, medical, etc. Polyimide thin films are especially useful in the electronics industry to protect the underlying devices from elevated temperatures, humidity, corrosive gases and high voltages. Therefore, the curing of polyimides has been studied extensively to ensure ideal material properties and new tools and methods for sample characterization are of great interest. Besides conventional techniques like Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA) or Differential Scanning Calorimetry (DSC), Laser Induced Breakdown Spectroscopy (LIBS) has been introduced recently to monitor the imidization reaction of a polyimide thin film. To obtain information about the temporal evolution of the reaction as well as optimize labor- and time-consuming sample preparation, a heating chamber for simultaneous thermal treatment and LIBS measurements (in-situ experiments) was developed and successfully used for imidization studies of self-synthesized polyimides. Besides a general introduction of the chamber design, the results of the in-situ investigation are presented: isothermal studies to gain temporal information about the imidization reaction of a single film and stepwise heating to investigate the influence of the curing temperature. Finally, LIBS depth-profiling revealed depth-resolved information about the imidization degree over the entire film thickness, illustrating one of the great advantages of the LIBS technique.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"141 ","pages":"Article 108647"},"PeriodicalIF":5.0,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-15DOI: 10.1016/j.polymertesting.2024.108645
Siheng Shao, Surya D. Pandita, Yuting Liu, Boru An, Theresa Morris, Tao Ma, Gerard F. Fernando
A novel electro-spinning method was used to produce highly aligned polyacrylonitrile (PAN) nano-fibre arrays. The tensile properties of the aligned fibres were investigated where three different adhesives were used in the end-tabs, namely, a photo-curable UV resin, super-glue and double-sided adhesive tape. The photo-curable UV adhesive and the super-glue were effective in enabling thorough impregnation of the nano-fibre arrays. However, the UV-resin offered greater control with regard to maintaining the impregnated area to within the end-tab region. On inspecting the stress/strain plots, it was concluded that the load-transfer from the end-tabs with the UV-adhesive was comparatively more uniform, repeatable and efficient. The ultimate tensile strength for the UV-adhesive, super-glue and double-sided adhesive tape were 76.71 ± 3.34, 68.80 ± 4.41 and 67.38 ± 2.21 MPa respectively and the Young's moduli were 4.05 ± 1.17, 2.50 ± 0.53 and 1.86 ± 0.53 GPa respectively. The failure strains for the test specimens with the three end-tab resins were similar and ranged between 22.46 ± 2.88 % and 23.73 ± 2.23 %. A phenomenological tensile model was applied to assess the tensile properties of the electro-spun PAN nano-fibres. The stress and stiffness calculated using the phenomenological tensile model were in agreement with the experimentally derived tensile data.
{"title":"The effect of end-tabbing methods on the tensile properties of electro-spun highly aligned PAN nano-fibres","authors":"Siheng Shao, Surya D. Pandita, Yuting Liu, Boru An, Theresa Morris, Tao Ma, Gerard F. Fernando","doi":"10.1016/j.polymertesting.2024.108645","DOIUrl":"10.1016/j.polymertesting.2024.108645","url":null,"abstract":"<div><div>A novel electro-spinning method was used to produce highly aligned polyacrylonitrile (PAN) nano-fibre arrays. The tensile properties of the aligned fibres were investigated where three different adhesives were used in the end-tabs, namely, a photo-curable UV resin, super-glue and double-sided adhesive tape. The photo-curable UV adhesive and the super-glue were effective in enabling thorough impregnation of the nano-fibre arrays. However, the UV-resin offered greater control with regard to maintaining the impregnated area to within the end-tab region. On inspecting the stress/strain plots, it was concluded that the load-transfer from the end-tabs with the UV-adhesive was comparatively more uniform, repeatable and efficient. The ultimate tensile strength for the UV-adhesive, super-glue and double-sided adhesive tape were 76.71 ± 3.34, 68.80 ± 4.41 and 67.38 ± 2.21 MPa respectively and the Young's moduli were 4.05 ± 1.17, 2.50 ± 0.53 and 1.86 ± 0.53 GPa respectively. The failure strains for the test specimens with the three end-tab resins were similar and ranged between 22.46 ± 2.88 % and 23.73 ± 2.23 %. A phenomenological tensile model was applied to assess the tensile properties of the electro-spun PAN nano-fibres. The stress and stiffness calculated using the phenomenological tensile model were in agreement with the experimentally derived tensile data.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"141 ","pages":"Article 108645"},"PeriodicalIF":5.0,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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