Pub Date : 2024-09-24DOI: 10.1016/j.polymertesting.2024.108599
Van-Kien Hoang , Kwak Jin Bae , Yuna Oh , Woohyeon Kwon , Jihyun Oh , Kyosun Ku , Minju Kim , Ki-Ho Nam , Jaesang Yu , Hyeonuk Yeo
Interest in thermosetting resins for polymer applications in extreme environments, such as aerospace, is increasing. The construction of oligoimide-based crosslinking systems has been the focus of considerable research over the past 30 years, but the analysis of chemical structure and molecular weight dependence has not been systematically performed. In this study, we established both theoretical and experimental frameworks by performing simulations based on a deep understanding of the crosslinking structure and conducted a systematic investigation of the properties of bulk specimens by synthesizing and preparing samples with various molecular weights. Theoretical investigations suggested clear differences and tendencies depending on molecular weight and crosslinking reaction pathways. Furthermore, experimental results showed excellent agreement with the simulations and clearly revealed the correlation between the molecular weights of pristine resin and thermal properties, such as glass transition and decomposition. In addition, we successfully obtained a thermosetting resin with superior thermal properties under optimized conditions, including a glass transition temperature exceeding 350 °C and a decomposition temperature exceeding 570 °C.
{"title":"Consideration of molecular weight-dependent high thermal resistance of end-capped-oligoimide based thermoset resins","authors":"Van-Kien Hoang , Kwak Jin Bae , Yuna Oh , Woohyeon Kwon , Jihyun Oh , Kyosun Ku , Minju Kim , Ki-Ho Nam , Jaesang Yu , Hyeonuk Yeo","doi":"10.1016/j.polymertesting.2024.108599","DOIUrl":"10.1016/j.polymertesting.2024.108599","url":null,"abstract":"<div><div>Interest in thermosetting resins for polymer applications in extreme environments, such as aerospace, is increasing. The construction of oligoimide-based crosslinking systems has been the focus of considerable research over the past 30 years, but the analysis of chemical structure and molecular weight dependence has not been systematically performed. In this study, we established both theoretical and experimental frameworks by performing simulations based on a deep understanding of the crosslinking structure and conducted a systematic investigation of the properties of bulk specimens by synthesizing and preparing samples with various molecular weights. Theoretical investigations suggested clear differences and tendencies depending on molecular weight and crosslinking reaction pathways. Furthermore, experimental results showed excellent agreement with the simulations and clearly revealed the correlation between the molecular weights of pristine resin and thermal properties, such as glass transition and decomposition. In addition, we successfully obtained a thermosetting resin with superior thermal properties under optimized conditions, including a glass transition temperature exceeding 350 °C and a decomposition temperature exceeding 570 °C.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"140 ","pages":"Article 108599"},"PeriodicalIF":5.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323676","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 : 2024-09-24DOI: 10.1016/j.polymertesting.2024.108598
Wenbo Gao , Xiarui Fan , Xinwei Zhou , Peng Ren
The impact of UV radiation on the high-temperature behavior of polyphenylene sulfide (PPS) fiber was investigated in this study. The ultimate strength, failure strain elasticity modulus and toughness were employed to evaluate the degradation caused by the coupling effects of UV radiation and high temperature. The degradation characteristics of PPS fiber were observed and evaluated based on the scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The results show that both UV exposure and high temperature can effectively reduce the mechanical performance of PPS fiber. The ultimate strength, failure strain and toughness were reduced to the minimum value after UV exposure 150h at room temperature. Both the initial and second elastic modulus of PPS fiber exhibited obvious decreasing trends with the UV exposure time and temperature increasing. The micro defects and molecular structure changes were detected as the degradation characteristics of PPS fiber caused by the coupling effects of UV radiation and high temperature. The Weibull model was applied to quantitatively analyze the dispersion of strength of PPS fiber under extreme conditions.
{"title":"Impact of UV irradiation on high-temperature behavior of polyphenylene sulfide fiber","authors":"Wenbo Gao , Xiarui Fan , Xinwei Zhou , Peng Ren","doi":"10.1016/j.polymertesting.2024.108598","DOIUrl":"10.1016/j.polymertesting.2024.108598","url":null,"abstract":"<div><div>The impact of UV radiation on the high-temperature behavior of polyphenylene sulfide (PPS) fiber was investigated in this study. The ultimate strength, failure strain elasticity modulus and toughness were employed to evaluate the degradation caused by the coupling effects of UV radiation and high temperature. The degradation characteristics of PPS fiber were observed and evaluated based on the scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The results show that both UV exposure and high temperature can effectively reduce the mechanical performance of PPS fiber. The ultimate strength, failure strain and toughness were reduced to the minimum value after UV exposure 150h at room temperature. Both the initial and second elastic modulus of PPS fiber exhibited obvious decreasing trends with the UV exposure time and temperature increasing. The micro defects and molecular structure changes were detected as the degradation characteristics of PPS fiber caused by the coupling effects of UV radiation and high temperature. The Weibull model was applied to quantitatively analyze the dispersion of strength of PPS fiber under extreme conditions.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"140 ","pages":"Article 108598"},"PeriodicalIF":5.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323677","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}
High-performance thermoplastic vulcanizates (TPVs) are a class of specialty polymers with exceptional mechanical properties, rubber-like elasticity, excellent processability and recyclability, and an excellent price-performance ratio that make them ideal for a variety of industrial applications. In this work, a successful method of creating high-performance TPV using a ternary blend of poly(methyl methacrylate) modified natural rubber (MGNR), poly(vinylidene fluoride) (PVDF), and fluorocarbon elastomer (FKM) was employed. Combining NR known for its exceptional rubber elasticity and resilience, with fluoropolymers, known for their exceptional chemical resistance and thermal stability, resulted in materials with a synergistic blend of properties. The developed PVDF/FKM/MGNR blend showed higher elasticity, tensile strength, and elongation at break than PVDF/FKM and PVDF/MGNR blends because the ternary blend had greatly improved phase morphology and compatibility between the three phases. The domain size in the ternary blend was smaller than 150 nm. The ternary blends also exhibited excellent thermal properties, where melting and crystallization temperatures were reduced significantly with MGNR due to possible dipole-dipole interactions. At the same time, the oil resistance and shape memory behavior of PVDF/FKM/MGNR were improved at an appropriate blend ratio. The ternary TPVs demonstrated good shape fixities (90–100 %) and shape recoveries (70–80 %). This research offers valuable insights into the design of high-performance thermoplastic elastomers based on natural rubber, which have excellent mechanical properties, solvent resistance, and potential for intelligent and lightweight application.
{"title":"A new strategy applying ternary blends of modified natural rubber with fluoroplastic and fluorocarbon elastomer for high-performance thermoplastic vulcanizate","authors":"Subhan Salaeh , Anoma Thitithammawong , Shib Shankar Banerjee","doi":"10.1016/j.polymertesting.2024.108594","DOIUrl":"10.1016/j.polymertesting.2024.108594","url":null,"abstract":"<div><div>High-performance thermoplastic vulcanizates (TPVs) are a class of specialty polymers with exceptional mechanical properties, rubber-like elasticity, excellent processability and recyclability, and an excellent price-performance ratio that make them ideal for a variety of industrial applications. In this work, a successful method of creating high-performance TPV using a ternary blend of poly(methyl methacrylate) modified natural rubber (MGNR), poly(vinylidene fluoride) (PVDF), and fluorocarbon elastomer (FKM) was employed. Combining NR known for its exceptional rubber elasticity and resilience, with fluoropolymers, known for their exceptional chemical resistance and thermal stability, resulted in materials with a synergistic blend of properties. The developed PVDF/FKM/MGNR blend showed higher elasticity, tensile strength, and elongation at break than PVDF/FKM and PVDF/MGNR blends because the ternary blend had greatly improved phase morphology and compatibility between the three phases. The domain size in the ternary blend was smaller than 150 nm. The ternary blends also exhibited excellent thermal properties, where melting and crystallization temperatures were reduced significantly with MGNR due to possible dipole-dipole interactions. At the same time, the oil resistance and shape memory behavior of PVDF/FKM/MGNR were improved at an appropriate blend ratio. The ternary TPVs demonstrated good shape fixities (90–100 %) and shape recoveries (70–80 %). This research offers valuable insights into the design of high-performance thermoplastic elastomers based on natural rubber, which have excellent mechanical properties, solvent resistance, and potential for intelligent and lightweight application.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"140 ","pages":"Article 108594"},"PeriodicalIF":5.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357565","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 : 2024-09-24DOI: 10.1016/j.polymertesting.2024.108595
Eduardo Burkot Hungria, Felipe Gonçalves Di Nisio, Francisco Cezar Cano, Rafael Voltolini, Neri Volpato
The strength of a printed polymeric component obtained by a material extrusion additive manufacturing technology is highly affected by the bonding quality between the deposited filaments (beads). Filament bonding is usually associated with material temperature and can be observed between layers (interlayer) and in the same layer (intralayer). The latter is not much explored in the literature and is rarely studied when the material extrusion must be resumed to complete a layer filling. A non-continuous tool path is usually found in filling complex part geometries with a raster strategy, where the area to be filled is divided into more than one continuous raster segment (CRS). The contact between the filaments of two adjacent CRSs (at 100 % density), defined as resumed contact (RC) for simplicity, can be affected by a weak bonding effect. This work aimed to experimentally study this effect by varying the time taken to resume printing, causing the temperature to drop at the RC, and measuring the influence on bonding strength. The bead width at the resumed extrusion was also analyzed. The results show that the influence of time taken to resume printing (contact temperature) on bonding strength was not significant for the part geometry tested and printer used. Notwithstanding, material failure under tensile load always occurred in the RC region. The results also showed some bead width variation due to under extrusion at the start of the extrusion, which can reduce the contact area. Therefore, the weak intralayer bonding at the RC is a fact, and it is affected, among others, by a combination of cold bonding and any contact area reduction due to under extrusion at the start of the extrusion. This issue must be carefully considered when printing an end-use part where the material strength is paramount.
{"title":"A study about weak intralayer bonding in extrusion-based additive manufacturing due to resumed extrusion during filling","authors":"Eduardo Burkot Hungria, Felipe Gonçalves Di Nisio, Francisco Cezar Cano, Rafael Voltolini, Neri Volpato","doi":"10.1016/j.polymertesting.2024.108595","DOIUrl":"10.1016/j.polymertesting.2024.108595","url":null,"abstract":"<div><div>The strength of a printed polymeric component obtained by a material extrusion additive manufacturing technology is highly affected by the bonding quality between the deposited filaments (beads). Filament bonding is usually associated with material temperature and can be observed between layers (interlayer) and in the same layer (intralayer). The latter is not much explored in the literature and is rarely studied when the material extrusion must be resumed to complete a layer filling. A non-continuous tool path is usually found in filling complex part geometries with a raster strategy, where the area to be filled is divided into more than one continuous raster segment (CRS). The contact between the filaments of two adjacent CRSs (at 100 % density), defined as resumed contact (RC) for simplicity, can be affected by a weak bonding effect. This work aimed to experimentally study this effect by varying the time taken to resume printing, causing the temperature to drop at the RC, and measuring the influence on bonding strength. The bead width at the resumed extrusion was also analyzed. The results show that the influence of time taken to resume printing (contact temperature) on bonding strength was not significant for the part geometry tested and printer used. Notwithstanding, material failure under tensile load always occurred in the RC region. The results also showed some bead width variation due to under extrusion at the start of the extrusion, which can reduce the contact area. Therefore, the weak intralayer bonding at the RC is a fact, and it is affected, among others, by a combination of cold bonding and any contact area reduction due to under extrusion at the start of the extrusion. This issue must be carefully considered when printing an end-use part where the material strength is paramount.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"140 ","pages":"Article 108595"},"PeriodicalIF":5.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328049","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 : 2024-09-24DOI: 10.1016/j.polymertesting.2024.108597
Xiangyan Yang , Runyu Zhou , Zixiao Xu , Jing Deng , Chuyue Wei , Jiahui Luo , Haoqi Luo , Lijia Zou , Yang Wu , Xin Ao , Shuaishuai Yuan , Weihua Zhou
Poly (4-hydroxybutyrate) (P4HB) is a marine biodegradable polyester with promising applications. Unfortunately, the crystallization and melting behavior of P4HB has not been systematically studied, due to the rapid crystallization near room temperature. In particular, the characterization of crystallization and melting of P4HB by fast scanning calorimetry (FSC) has not been reported previously. In this article, the common differential scanning calorimeter (DSC), polarized optical microscopy (POM), atomic force microscopy (AFM) and FSC were performed to investigate the crystallization and melting behavior of P4HB. The results indicated that melt crystallization facilitated the formation of fragmented crystals rather than complete spherulites. Furthermore, the P4HB exhibited a broad crystallization temperature range from −19 °C to 49 °C, and the crystallization and melting of P4HB was notably affected by the temperature, in addition to the heating or cooling rates. The higher crystallization temperature and lower cooling rates facilitated the formation of well-developed crystals. Remarkably, the P4HB is found to be unable to crystallize at heating or cooling rates exceeding 6 K/s. Moreover, double melting peaks could be discerned at moderate isothermal crystallization temperature exhibiting faster crystallization rate. The findings will provide theoretical guidance on how to optimize the processing parameters in modulating the crystallization of P4HB.
{"title":"Crystallization and melting of Poly(4-hydroxybutyrate) characterized by fast scanning calorimetry","authors":"Xiangyan Yang , Runyu Zhou , Zixiao Xu , Jing Deng , Chuyue Wei , Jiahui Luo , Haoqi Luo , Lijia Zou , Yang Wu , Xin Ao , Shuaishuai Yuan , Weihua Zhou","doi":"10.1016/j.polymertesting.2024.108597","DOIUrl":"10.1016/j.polymertesting.2024.108597","url":null,"abstract":"<div><div>Poly (4-hydroxybutyrate) (P4HB) is a marine biodegradable polyester with promising applications. Unfortunately, the crystallization and melting behavior of P4HB has not been systematically studied, due to the rapid crystallization near room temperature. In particular, the characterization of crystallization and melting of P4HB by fast scanning calorimetry (FSC) has not been reported previously. In this article, the common differential scanning calorimeter (DSC), polarized optical microscopy (POM), atomic force microscopy (AFM) and FSC were performed to investigate the crystallization and melting behavior of P4HB. The results indicated that melt crystallization facilitated the formation of fragmented crystals rather than complete spherulites. Furthermore, the P4HB exhibited a broad crystallization temperature range from −19 °C to 49 °C, and the crystallization and melting of P4HB was notably affected by the temperature, in addition to the heating or cooling rates. The higher crystallization temperature and lower cooling rates facilitated the formation of well-developed crystals. Remarkably, the P4HB is found to be unable to crystallize at heating or cooling rates exceeding 6 K/s. Moreover, double melting peaks could be discerned at moderate isothermal crystallization temperature exhibiting faster crystallization rate. The findings will provide theoretical guidance on how to optimize the processing parameters in modulating the crystallization of P4HB.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"140 ","pages":"Article 108597"},"PeriodicalIF":5.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319045","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 : 2024-09-19DOI: 10.1016/j.polymertesting.2024.108584
Zhibo Wu , Jianping Yin , Meng Li , Wenxuan Du , Xuanfu He , Zhongbin Tang , Yinggang Miao
The composite modified double-base propellants (CMDB) were experimentally investigated for mechanical behavior under wide tension strain rate loading from 0.0001 s−1 to 2500 s−1, based on Instron mechanical machine and modified Hopkinson tension bar technique. Stress-strain curves were obtained for its strain rate effect and integrality evaluation. The results indicated that CMDB presents high rate-dependence with flow stress distinctly increase as loading strain rate increasing. A succinct constitutive formulation is established with only five parameters, to characterize well the rate-dependence and strain hardening behavior. The fracture morphologies were investigated by scanning electron microscopy, and it is indicated that they are also rate-dependent: the cavitation and matrix damage induced from matrix deformation work less but more RDX particles fractures with strain rate increasing. Equivalent unit cell model with brittle cracking was established to simulate the mechanical behavior and failure characteristics of CMDB. The results reveal that with increasing loading strain rates, CMDB presents a tough-brittle transition, with less cavitation and matrix damage induced by matrix deformation, while more RDX particles fracture. Series of simulated results confirm qualitatively the experimental observations, and the obtained stress contours facilitate to validate the observed characteristics and propose reasonable mechanisms.
{"title":"Rate-dependent constitutive behavior and mechanism of CMDB under tension loading","authors":"Zhibo Wu , Jianping Yin , Meng Li , Wenxuan Du , Xuanfu He , Zhongbin Tang , Yinggang Miao","doi":"10.1016/j.polymertesting.2024.108584","DOIUrl":"10.1016/j.polymertesting.2024.108584","url":null,"abstract":"<div><div>The composite modified double-base propellants (CMDB) were experimentally investigated for mechanical behavior under wide tension strain rate loading from 0.0001 s<sup>−1</sup> to 2500 s<sup>−1</sup>, based on Instron mechanical machine and modified Hopkinson tension bar technique. Stress-strain curves were obtained for its strain rate effect and integrality evaluation. The results indicated that CMDB presents high rate-dependence with flow stress distinctly increase as loading strain rate increasing. A succinct constitutive formulation is established with only five parameters, to characterize well the rate-dependence and strain hardening behavior. The fracture morphologies were investigated by scanning electron microscopy, and it is indicated that they are also rate-dependent: the cavitation and matrix damage induced from matrix deformation work less but more RDX particles fractures with strain rate increasing. Equivalent unit cell model with brittle cracking was established to simulate the mechanical behavior and failure characteristics of CMDB. The results reveal that with increasing loading strain rates, CMDB presents a tough-brittle transition, with less cavitation and matrix damage induced by matrix deformation, while more RDX particles fracture. Series of simulated results confirm qualitatively the experimental observations, and the obtained stress contours facilitate to validate the observed characteristics and propose reasonable mechanisms.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"140 ","pages":"Article 108584"},"PeriodicalIF":5.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0142941824002617/pdfft?md5=67a7f8df95eea02630e626e3af4de1d7&pid=1-s2.0-S0142941824002617-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314987","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 : 2024-09-19DOI: 10.1016/j.polymertesting.2024.108583
Jianbo Fu , Hui Ren , Xiaohan Liu , Jianjun Sun , Guoqing Wu
The migration behavior of nitrate ester-plasticized polyether (NEPE) propellant components significantly impacts safety. Experimentally observing the migration process is challenging and time-consuming. This study employed molecular dynamics (MD) methods to simulate a molecular model of the NEPE propellant/liner interface layer, enabling the prediction of component migration behavior. We visualized the migration process of all propellant components and studied the interface layer components' migration patterns, diffusion coefficients, and concentration gradient distributions. The contents of migrated components of the propellant and liner at different accelerated aging times at 70 °C were determined using high-performance liquid chromatography (HPLC), and the simulation patterns were compared with experimental observations. The results indicate that the migrated components in the propellant mainly consist of nitrate esters (Nitroglycerin, abbreviated as NG, and Butanetriol Trinitrate, abbreviated as BTTN), stabilizers (NMethylnitroaniline, abbreviated as MNA, and 2-Nitrodiphenylamine, abbreviated as 2-NDPA), and solid component (Hexahydro-1,3,5-trinitro-1,3,5-triazine, abbreviated as RDX). The migration process is primarily dominated by the substantial migration of nitrate esters, which is a key factor contributing to the degradation of propellant performance during storage. The migration process can be divided into three stages: swift migration, steady slow migration, and migration equilibrium. The diffusion coefficients are ranked from most significant to most minor as NG > BTTN > RDX > MNA > 2-NDPA. Three migration stages consistent with the simulation process were observed using HPLC, and the migration behavior of nitrate esters aligned with simulation patterns. Our designed full-component model can qualitatively predict component migration behavior. Additionally, a faster diffusion coefficient does not necessarily lead to a greater amount of migration. We employed MD simulations combined with density functional theory (DFT) calculations to explain this phenomenon and found that intermolecular interactions may influence the diffusion coefficient. At the same time, the migration amount is highly correlated with molecular polarity. Therefore, increasing the molecular polarity difference between easily migrating components and liner materials is a beneficial strategy for slowing the migration process and enhancing the storage safety of propellants.
{"title":"Analysis and prediction for dynamic migration behavior of NEPE propellant/liner interface layer full components","authors":"Jianbo Fu , Hui Ren , Xiaohan Liu , Jianjun Sun , Guoqing Wu","doi":"10.1016/j.polymertesting.2024.108583","DOIUrl":"10.1016/j.polymertesting.2024.108583","url":null,"abstract":"<div><div>The migration behavior of nitrate ester-plasticized polyether (NEPE) propellant components significantly impacts safety. Experimentally observing the migration process is challenging and time-consuming. This study employed molecular dynamics (MD) methods to simulate a molecular model of the NEPE propellant/liner interface layer, enabling the prediction of component migration behavior. We visualized the migration process of all propellant components and studied the interface layer components' migration patterns, diffusion coefficients, and concentration gradient distributions. The contents of migrated components of the propellant and liner at different accelerated aging times at 70 °C were determined using high-performance liquid chromatography (HPLC), and the simulation patterns were compared with experimental observations. The results indicate that the migrated components in the propellant mainly consist of nitrate esters (Nitroglycerin, abbreviated as NG, and Butanetriol Trinitrate, abbreviated as BTTN), stabilizers (NMethylnitroaniline, abbreviated as MNA, and 2-Nitrodiphenylamine, abbreviated as 2-NDPA), and solid component (Hexahydro-1,3,5-trinitro-1,3,5-triazine, abbreviated as RDX). The migration process is primarily dominated by the substantial migration of nitrate esters, which is a key factor contributing to the degradation of propellant performance during storage. The migration process can be divided into three stages: swift migration, steady slow migration, and migration equilibrium. The diffusion coefficients are ranked from most significant to most minor as NG > BTTN > RDX > MNA > 2-NDPA. Three migration stages consistent with the simulation process were observed using HPLC, and the migration behavior of nitrate esters aligned with simulation patterns. Our designed full-component model can qualitatively predict component migration behavior. Additionally, a faster diffusion coefficient does not necessarily lead to a greater amount of migration. We employed MD simulations combined with density functional theory (DFT) calculations to explain this phenomenon and found that intermolecular interactions may influence the diffusion coefficient. At the same time, the migration amount is highly correlated with molecular polarity. Therefore, increasing the molecular polarity difference between easily migrating components and liner materials is a beneficial strategy for slowing the migration process and enhancing the storage safety of propellants.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"140 ","pages":"Article 108583"},"PeriodicalIF":5.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0142941824002605/pdfft?md5=37f73a6b1617f87a1f992a25c91c6644&pid=1-s2.0-S0142941824002605-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311991","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 : 2024-09-19DOI: 10.1016/j.polymertesting.2024.108585
Ran Yang , Shuwei Xu , Hui Wang , Xinxing Wu , Shuaibo Han , Chunde Jin , Fangli Sun , Yizhong Cao , Qiang Wu
The mechanical robustness of structural adhesives as represented by phenol formaldehyde (PF) adhesive is vital for the safe service of engineered wood/bamboo products facing environmental aggressors. Here, fungal decay-provoked hazard towards the mechanical robustness of PF adhesive was demonstrated, which was usually overlooked in previous works. Obtained results proved that the white rot (Trametes versicolor, T. versicolor) and brown rot (Gloeophyllum trabeum, G. trabeum) fungus can both grow on the surface of cured commercial PF adhesive. An evident oxidization can only be observed on the T. versicolor-decayed PF adhesive, as along with the appearance of 2,6-bis(1,1-dimethylethyl)-1,4-benzenediol after decay. It further demonstrated the ruptured and oxidized cross-linking structures. The evident degradation of PF adhesive can be assigned to the favored activity of laccase (40.9 U mL−1) and lignin peroxidase (60.5 U mL−1) during the decay of T. versicolor. The elastic modulus and hardness of PF adhesive reduced by over 31.6 % and 50.2 %, respectively, which is also accompanied by the elevation in the creep deformation (45.4 %), after a 40-day T. versicolor decay. This work revealed the decay-sensitivity of PF adhesive, and the cleavage of cross-linking structures is the major trigger for the degraded mechanical robustness of PF adhesive after decay.
以苯酚甲醛（PF）粘合剂为代表的结构粘合剂的机械坚固性对于面对环境侵害的工程木/竹产品的安全使用至关重要。在此，我们展示了真菌腐烂对苯酚甲醛胶粘剂机械坚固性的危害，这在以往的研究中通常被忽视。研究结果证明，白腐菌（Trametes versicolor，T. versicolor）和褐腐菌（Gloeophyllum trabeum，G. trabeum）都能在固化的商用聚苯乙烯粘合剂表面生长。只有在 T. versicolor 腐烂的 PF 粘合剂上才能观察到明显的氧化现象，腐烂后还会出现 2,6-双（1,1-二甲基乙基）-1,4-苯二酚。这进一步证明了交联结构的破裂和氧化。PF 粘合剂的明显降解可归因于 T. versicolor 腐烂过程中漆酶（40.9 U mL-1）和木质素过氧化物酶（60.5 U mL-1）的活性。经过 40 天的 T. versicolor 腐化后，PF 粘合剂的弹性模量和硬度分别降低了 31.6% 和 50.2%，蠕变变形也增加了 45.4%。这项工作揭示了 PF 粘合剂对腐烂的敏感性，交联结构的裂解是 PF 粘合剂在腐烂后机械坚固性下降的主要诱因。
{"title":"Fungal decay-provoked degradation of cross-linking networks in phenol-formaldehyde adhesive: From fragmentation process towards damaged mechanical robustness","authors":"Ran Yang , Shuwei Xu , Hui Wang , Xinxing Wu , Shuaibo Han , Chunde Jin , Fangli Sun , Yizhong Cao , Qiang Wu","doi":"10.1016/j.polymertesting.2024.108585","DOIUrl":"10.1016/j.polymertesting.2024.108585","url":null,"abstract":"<div><div>The mechanical robustness of structural adhesives as represented by phenol formaldehyde (PF) adhesive is vital for the safe service of engineered wood/bamboo products facing environmental aggressors. Here, fungal decay-provoked hazard towards the mechanical robustness of PF adhesive was demonstrated, which was usually overlooked in previous works. Obtained results proved that the white rot (<em>Trametes versicolor, T. versicolor</em>) and brown rot (<em>Gloeophyllum trabeum, G. trabeum</em>) fungus can both grow on the surface of cured commercial PF adhesive. An evident oxidization can only be observed on the <em>T. versicolor</em>-decayed PF adhesive, as along with the appearance of 2,6-bis(1,1-dimethylethyl)-1,4-benzenediol after decay. It further demonstrated the ruptured and oxidized cross-linking structures. The evident degradation of PF adhesive can be assigned to the favored activity of laccase (40.9 U mL<sup>−1</sup>) and lignin peroxidase (60.5 U mL<sup>−1</sup>) during the decay of <em>T. versicolor</em>. The elastic modulus and hardness of PF adhesive reduced by over 31.6 % and 50.2 %, respectively, which is also accompanied by the elevation in the creep deformation (45.4 %), after a 40-day <em>T. versicolor</em> decay. This work revealed the decay-sensitivity of PF adhesive, and the cleavage of cross-linking structures is the major trigger for the degraded mechanical robustness of PF adhesive after decay.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"140 ","pages":"Article 108585"},"PeriodicalIF":5.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0142941824002629/pdfft?md5=deb88b16ae5cc784d1c2058970370c56&pid=1-s2.0-S0142941824002629-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311994","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 : 2024-09-18DOI: 10.1016/j.polymertesting.2024.108581
C. Le Talludec , H. Ono , K. Ohyama , S. Nishimura , A. Nait-Ali , H.A. Cayzac , S. Tencé-Girault , S. Castagnet
The objective was to evaluate the impact of repeated exposure to hyperbaric hydrogen (90 MPa; 30 °C) and pressure release on the microstructure and mechanical behavior of PA11. Samples were analyzed after 1, 2, 5 and 10 cycles, by SAXS, WAXS, DMA, DSC, and a series of mechanical tests with variable triaxiality ratio. The most visible change in the residual state after desorption was a stiffening of the amorphous phase. It mainly originated from the first cycle, especially the first pressurization. The crystalline phase was slightly affected and no evidence of nano-voiding was brought in the residual state up to 10 cycles. Similar analyses were conducted during the first cycle's desorption transient. They showed a reversible plasticizing effect and a trend of nano-voiding vanishing after desorption but might promote damage upon further triaxial loading.
{"title":"Consequences of repeated hyperbaric hydrogen exposures on mechanical properties and microstructure of polyamide 11","authors":"C. Le Talludec , H. Ono , K. Ohyama , S. Nishimura , A. Nait-Ali , H.A. Cayzac , S. Tencé-Girault , S. Castagnet","doi":"10.1016/j.polymertesting.2024.108581","DOIUrl":"10.1016/j.polymertesting.2024.108581","url":null,"abstract":"<div><div>The objective was to evaluate the impact of repeated exposure to hyperbaric hydrogen (90 MPa; 30 °C) and pressure release on the microstructure and mechanical behavior of PA11. Samples were analyzed after 1, 2, 5 and 10 cycles, by SAXS, WAXS, DMA, DSC, and a series of mechanical tests with variable triaxiality ratio. The most visible change in the residual state after desorption was a stiffening of the amorphous phase. It mainly originated from the first cycle, especially the first pressurization. The crystalline phase was slightly affected and no evidence of nano-voiding was brought in the residual state up to 10 cycles. Similar analyses were conducted during the first cycle's desorption transient. They showed a reversible plasticizing effect and a trend of nano-voiding vanishing after desorption but might promote damage upon further triaxial loading.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"140 ","pages":"Article 108581"},"PeriodicalIF":5.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0142941824002587/pdfft?md5=cd082cd9c7d0bf3ab040f00a76e09320&pid=1-s2.0-S0142941824002587-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311993","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 : 2024-09-18DOI: 10.1016/j.polymertesting.2024.108578
Aswani Kumar Bandaru , Jayaram R. Pothnis , Alexandre Portela , Raghavendra Gujjala , Hong Ma , Ronan M. O'Higgins
This experimental work presents a comparative study on the mechanical behaviour of novel infusible methylmethacrylate matrix (Elium®) composites reinforced with different types of high-performance fibres. A vacuum-assisted resin infusion process was employed to fabricate the laminates using carbon, basalt, Kevlar®, and high molecular weight polyethene (UHMWPE) fibres. Flexural and interlaminar shear properties of the composites were evaluated. Test results revealed that carbon fibre composites had superior flexural strength, stiffness and interlaminar shear stress as compared to the other composites tested. Further, composites containing Kevlar and UHMWPE fibres demonstrated significantly higher flexural strains to failure. Post-testing, specimens were examined using scanning electron microscopy (SEM). Microscopy revealed possible interfacial interaction differences based on the reinforcement fibre type, which was further confirmed by an analytical approach for analysing the flexural behaviour of various types of composites. The sequence of damage progression in specimens was also analysed.
{"title":"Flexural and interlaminar shear response of novel methylmethacrylate composites reinforced with high-performance fibres","authors":"Aswani Kumar Bandaru , Jayaram R. Pothnis , Alexandre Portela , Raghavendra Gujjala , Hong Ma , Ronan M. O'Higgins","doi":"10.1016/j.polymertesting.2024.108578","DOIUrl":"10.1016/j.polymertesting.2024.108578","url":null,"abstract":"<div><div>This experimental work presents a comparative study on the mechanical behaviour of novel infusible methylmethacrylate matrix (Elium®) composites reinforced with different types of high-performance fibres. A vacuum-assisted resin infusion process was employed to fabricate the laminates using carbon, basalt, Kevlar®, and high molecular weight polyethene (UHMWPE) fibres. Flexural and interlaminar shear properties of the composites were evaluated. Test results revealed that carbon fibre composites had superior flexural strength, stiffness and interlaminar shear stress as compared to the other composites tested. Further, composites containing Kevlar and UHMWPE fibres demonstrated significantly higher flexural strains to failure. Post-testing, specimens were examined using scanning electron microscopy (SEM). Microscopy revealed possible interfacial interaction differences based on the reinforcement fibre type, which was further confirmed by an analytical approach for analysing the flexural behaviour of various types of composites. The sequence of damage progression in specimens was also analysed.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"140 ","pages":"Article 108578"},"PeriodicalIF":5.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0142941824002551/pdfft?md5=d4b69dde211987c5817c2f98b755365f&pid=1-s2.0-S0142941824002551-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315065","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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