Polymer Testing最新文献

{"title":"Measurement of axial and shear mechanical response of PDMS elastomers and determination of Poisson's ratio using digital image correlation","authors":"Satya Pal,&nbsp;Abir Bhattacharyya","doi":"10.1016/j.polymertesting.2025.108687","DOIUrl":"10.1016/j.polymertesting.2025.108687","url":null,"abstract":"<div><div>Measurement of stress-strain response under different deformation modes is important for developing constitutive models of soft polymers. However, such measurements on soft and compliant polymers are challenging using traditional techniques due to generation of unwanted stress concentrations leading to premature failure during loading. In this study, a non-contact digital image correlation (DIC) technique along with a novel experimental setup were used to accurately measure the strain field on a specimen surface subjected to finite strain. Polydimethylsiloxane (PDMS) elastomers of three different base polymer to hardener ratio were characterized under three different deformation modes— uniaxial compression, uniaxial tension, and simple shear—over strain rates ranging between 10⁻³/s–10⁻¹/s. The resulting strain fields exhibited uniformity across all the deformation modes up to finite strains. While the lower strain rate experiments are minimally affected by strain acceleration and inertia effects, the specimens loaded under higher strain rate (10⁻¹/s) are initially affected by strain acceleration during loading, which precluded reliable determination of Young's moduli and shear moduli from the initial slope of the stress-strain responses. The Poisson's ratio calculated from the ratio between measured axial and lateral strains was close to 0.5 at small strains, and exhibited a close match with that calculated from Young's modulus (<em>E</em>) to shear modulus (<em>G</em>) ratio (<em>E/G),</em> validating linear elasticity theory at small strains. The tangent moduli for all the compositions were found to be practically strain-rate insensitive in the region of steady strain rate.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108687"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137212","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}

{"title":"Understanding the post-curing behaviors of polymethylacrylimide: Curing kinetics and molecular mobility","authors":"Yuan Chen ,&nbsp;Xiaolian Qiang ,&nbsp;Yaping Zhang ,&nbsp;Ningning Song ,&nbsp;Lixian Guo ,&nbsp;Siyuan Zhang ,&nbsp;Chunrong Tian ,&nbsp;Keping Chen","doi":"10.1016/j.polymertesting.2025.108720","DOIUrl":"10.1016/j.polymertesting.2025.108720","url":null,"abstract":"<div><div>In this study, the post-curing kinetic, molecular mobility and mechanical behavior of polymethylacrylimide (PMI), synthesized from methacrylic acid and methacrylonitrile, were systematically investigated. Differential scanning calorimetry results identified three distinct temperature zones during the post-curing process, which represented different types of curing reactions. Model-free kinetic methods were used to evaluate the post-curing kinetics of PMI materials. Fourier transform infrared spectroscopy demonstrated that the cyclization of anhydride groups predominantly occurred at lower post-curing temperatures, while the decomposition and transformation were observed at higher temperatures. Meanwhile, there was a progressive formation of imide rings with the increase of post-curing temperature. In addition, the molecular segment mobility of PMI materials was investigated via dielectric relaxation spectroscopy, and molecular segment mobility was gradually restricted during the post-curing process, indicated the formation of crosslinked network structure. Those changes of microstructures agreed well with the evolution of compressive properties. This study provides insights into the curing kinetics and structural evolution of PMI during post-curing process, offering guidance for optimizing post-curing conditions to achieve superior mechanical performance.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108720"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137206","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}

{"title":"Mechanical performance of 3D-printed TPU auxetic structures for energy absorption applications","authors":"Sergio Fuentes del Toro ,&nbsp;Jorge Crespo-Sanchez ,&nbsp;Jorge Ayllón ,&nbsp;Alvaro Rodríguez-Prieto ,&nbsp;Ana María Camacho","doi":"10.1016/j.polymertesting.2024.108669","DOIUrl":"10.1016/j.polymertesting.2024.108669","url":null,"abstract":"<div><div>The emergence of metamaterials and layered structures obtained through additive manufacturing (AM) techniques opens a new paradigm of mechanical properties for advanced applications that need to be explored. This study investigates the mechanical behavior of 3D-printed auxetic structures, fabricated from thermoplastic polyurethane (TPU), under tensile and compressive loads. Utilizing fused deposition modeling (MEX), we examined the influence of printing direction on the anisotropic mechanical properties of TPU, with a particular focus on energy absorption, stress–strain responses, and damping capabilities. The research employs the Ogden model for hyperelastic characterization, demonstrating excellent correlation with experimental data. Thus, the novelty of this work relies on an approach that – with a focus in the precision and accuracy of the mechanical performance assessment – through a robust novel methodology combining the Ogden’s analytical model with numerical simulation provided by Ansys® and experimental tests of tensile and compression allows to comprehensively understand the mechanical performance of novel auxetic structures intended to energy absorption and impact resistance applications. Our findings reveal significant variations in mechanical performance based on printing orientation, with the 0°direction offering superior ductility and strength. These results suggest that optimizing the printing direction is crucial for enhancing the performance of TPU auxetic structures, particularly in applications requiring high impact resistance, energy absorption, and damping. This study contributes to the advancement of 3D printing technology for the development of next-generation materials with potential applications in protective gear, medical devices or damping devices, among others.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108669"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137210","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}

{"title":"Facile grafting method achieves Unprecedented dispersion stability of carbon black in PP fiber","authors":"Yaoming Wang ,&nbsp;Guihao Liu ,&nbsp;Yuqing Liu ,&nbsp;Yiqing Zhang ,&nbsp;Guangtao Chang ,&nbsp;Ruoxin Li","doi":"10.1016/j.polymertesting.2025.108698","DOIUrl":"10.1016/j.polymertesting.2025.108698","url":null,"abstract":"<div><div>Carbon black (CB) offers valuable properties, but its tendency to agglomerate hinders its full potential in polymer applications. This study presents a novel and straightforward graft modification method to overcome this limitation. By covalently bonding organic functional groups to the CB surface, the surface energy of carbon black was significantly reduced and enhanced its compatibility with organic PP polymers. Characterization techniques (FTIR, XPS, Raman, TGA, etc.) confirm successful grafting and demonstrate excellent dispersion stability of modified CB in organic media. The modified CB exhibits uniform dispersion and reduced particle size within polypropylene (PP) fibers, leading to tensile strength increased dramatically from 103 MPa (unmodified) to 517 MPa (modified). Moreover, the strain reached 1086 %, exceeding both unmodified CB or commercial CB concentrate modified polypropylene (PP) fibers by 31 % and 11 %, respectively. This method represents a significant advancement over existing techniques by providing a straightforward and efficient approach to developing high-strength polypropylene fibers with exceptional tensile and strain characteristics for coloring synthetic fiber applications.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108698"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137215","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}

{"title":"Fiber Bragg grating in-situ detection method for curing characteristics of GIS epoxy/Al2O3 composite insulation materials","authors":"Yingying Zhang,&nbsp;Yanpeng Hao,&nbsp;Zikui Shen,&nbsp;Dongyuan Du,&nbsp;Hongru Mi","doi":"10.1016/j.polymertesting.2025.108701","DOIUrl":"10.1016/j.polymertesting.2025.108701","url":null,"abstract":"<div><div>Excessive residual strain generated by curing shrinkage of epoxy/Al₂O₃ composite insulation materials can reduce the mechanical properties of gas-insulated metal-enclosed switchgear (GIS) insulators. The process and formula optimization of insulators lack effective detection methods. A thermocouple-compensated fiber Bragg grating in-situ detection method for seven high-temperature curing characteristics is proposed. The curing shrinkage characteristics and residual strain generation mechanism of this material cured at 114 °C are studied. The cured residual strain is calculated by the total central wavelength shift of the grating and the thermocouple temperature change inside the sample at the end of the curing process. The curing degree, curing initiation time, and curing completion time are calculated by the temperature inside the sample and the surface temperature of the mold based on the law of thermal equilibrium. Gel time, gel temperature, and glass transition temperature are detected by linear fitting and differential analysis of the strain variation with temperature inside the sample based on the thermal expansion coefficient. Differential scanning calorimetry and SB(<em>m</em>, <em>n</em>) autocatalytic reaction model are used to calculate the curing kinetic equation and to comparatively verify the glass transition temperature and curing degree. The differences between the two test results of the glass transition temperature, curing initiation time, and curing completion time are 0.39 %, 11.2 %, and 17.6 %, respectively. The proposed method can be used for detecting and evaluating the processes and formulations of GIS insulators in the same batch of production samples and optimizing the processes and formulations.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108701"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137217","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}

{"title":"Influence of thermoplastic polyurethane (TPU) and printing parameters on the thermal and mechanical performance of polylactic acid (PLA) / thermoplastic polyurethane (TPU) polymer","authors":"Muhammad Nafiz Hamidi,&nbsp;Jamaluddin Abdullah,&nbsp;Abdus Samad Mahmud,&nbsp;Muhammad Hafiz Hassan,&nbsp;Ahmad Yasier Zainoddin","doi":"10.1016/j.polymertesting.2025.108697","DOIUrl":"10.1016/j.polymertesting.2025.108697","url":null,"abstract":"<div><div>Polylactic acid (PLA) is a polymer widely used for 3D printing process owing to its mechanical properties which are high strength and flexural modulus and environmentally friendly. However, PLA is also a brittle polymer with low impact resistance. This weakness can be compensated by combining PLA with other polymer like Thermoplastic polyurethane (TPU) that is widely used to improve mechanical properties of PLA. In polymer 3D printing process, printing parameters affect the thermo-mechanical properties of the printed products. This study investigates the influence of TPU and various printing parameters on thermal and mechanical properties of PLA/TPU polymer blends. It provides more precise understanding on how each printing parameters and different TPU ratio affect the mechanical and thermal properties. It also helps in determining the significant parameters for better PLA/TPU blend print. This exploration of parameter effects adds novel insights, enhancing applicability in practical 3D printing processes. Six different TPU ratio was used which are 10 %–50 % by weight while the parameters being tested are printing speed, raster angle, layer thickness and printing temperature. The differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were conducted to assess the thermal properties while a tensile test was conducted to evaluate the mechanical properties. ANOVA analysis was employed for the data analysis. It was found that TPU altered the thermal properties of PLA by reducing the cold crystallization temperature, T_cc, enthalpy of crystallization, ΔH_c and enthalpy of melting, ΔH_m. The mechanical strength reduced by 64 % but the ductility improved up to 900 %. Based on ANOVA analysis, it can be concluded that influence of printing parameters on the mechanical properties are layer thickness &gt; printing speed &gt; raster angle &gt; printing temperature in descending order.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108697"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137157","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}

{"title":"Effect of hard segment content on the phase separation and properties of hydroxyl-terminated polybutadiene thermoplastic polyurethane","authors":"Boxin Liu ,&nbsp;Zhihao Niu ,&nbsp;Zhanglei Wang ,&nbsp;Yimin Wang ,&nbsp;Hua Zou ,&nbsp;Xiuying Zhao ,&nbsp;Shikai Hu","doi":"10.1016/j.polymertesting.2024.108681","DOIUrl":"10.1016/j.polymertesting.2024.108681","url":null,"abstract":"<div><div>Thermoplastic polyurethane (TPU) possesses a distinctive microphase separation structure resulting from the thermodynamic incompatibility between its soft and hard segments. The content of hard segments is a significant factor that impacts the micromorphology and associated properties of TPU. In this study, hydroxyl-terminated polybutadiene thermoplastic polyurethanes (HTPB-TPUs) were synthesized using a two-step method in which hydroxyl-terminated polybutadiene, toluene diisocyanate, and 1,4-butanediol were incorporated. These HTPB-TPUs were designed to lack hydrogen bonding between the soft and hard segments. The structure and properties of the HTPB-TPUs were comprehensively evaluated. The results demonstrated a noticeable influence of the hard segment content on the degree of microphase separation. A combination of analytical techniques was employed to elucidate the effect of hard segment content on phase separation. Additionally, all-atom molecular dynamics simulations were conducted to determine the number of hydrogen bonds. These simulations served to verify the impact of the hard segment content on phase separation. Furthermore, the relationship between the hard segment content and the mechanical properties was elucidated by examining the phase separation phenomenon. This study provides valuable insights into the interaction between the structure and properties of TPU, laying a foundation for future investigations in this area.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108681"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137208","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}

{"title":"Monitoring the repair process of internal microdamages in thermoplastic composites using optical coherence tomography","authors":"Pinbo Huang ,&nbsp;Changhao Wang ,&nbsp;Weirui Zhang ,&nbsp;Zihao Ni ,&nbsp;Rufeng You","doi":"10.1016/j.polymertesting.2025.108689","DOIUrl":"10.1016/j.polymertesting.2025.108689","url":null,"abstract":"<div><div>The reliability of composite structures critically depends on effective damage repair. This study employs optical coherence tomography (OCT), a non-destructive imaging technique capable of generating cross-sectional images of translucent materials, to investigate the repair of early-stage microdamage in thermoplastic composites. Using electrical resistance heating, the healing of a microscale void in a carbon fiber-reinforced ethylene-vinyl acetate (EVA) polymer sample was monitored through OCT-derived scattered light intensity and phase difference measurements. Firstly, the void healing process was observed using a self-developed OCT system. Repair parameters, including initiation and completion times, were then estimated from the scattered light intensity changes in the defective region. Additionally, phase-contrast imaging was utilized to analyze phase difference patterns, enabling the computation of displacement fields across the defective cross-section and providing quantitative insights into the healing dynamics. The findings demonstrate the efficacy of OCT in monitoring and characterizing the repair processes of composite materials, highlighting its potential as a valuable tool in structural health assessment.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108689"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137211","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}

{"title":"Complex cure kinetics of self-healing copolyester vitrimers via isothermal thermogravimetric analysis","authors":"Louis O. Vaught ,&nbsp;Jacob L. Meyer ,&nbsp;Omar El Arwadi ,&nbsp;Tanaya Mandal ,&nbsp;Ahmad Amiri ,&nbsp;Mohammad Naraghi ,&nbsp;Andreas A. Polycarpou","doi":"10.1016/j.polymertesting.2025.108724","DOIUrl":"10.1016/j.polymertesting.2025.108724","url":null,"abstract":"<div><div>Thermogravimetric Analysis (TGA) is a valuable tool for studying chemical reactions that release volatile compounds. Constant-temperature TGA can be particularly useful for polymer cure reactions with complex, time-evolving phenomenology, by ensuring time and temperature effects remain separable. In this work, a compound isothermal TGA methodology is developed to study the cure process of high-performance vitrimers known as Aromatic Thermosetting coPolyesters (ATSP). By fitting observed mass loss to a nondimensional phenomenological model with generalized terms and introducing additional nonphysical terms to account both known and suspected non-cure behaviors, changes in cure kinetics were evaluated across a wide range of temperatures (210°C–380 °C). The activation of the added nonphysical terms was used to differentiate between expected cure behavior (240°C–340 °C), and cures involving precursor decomposition (&gt;340 °C). An unexpected cure-like reaction below cure temperature (&lt;240 °C) was hypothesized to correspond to self-healing bond exchange, which is well-understood to cause changes in molecular weight in thermoplastic polyesters. This was directly validated via evolved gas analysis, and activation energies were calculated for the cure-dominant region of the reaction. These activation energies were found to be similar across different polymer formulations. When combined with significant observed mass loss below the expected cure temperature and findings in prior work, this indicates that the apparent cure process may be driven by thermodynamically-favorable bond exchange reactions.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108724"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313090","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}

{"title":"Comparative study on taper preparation techniques for direct internal structure analysis of organic coatings applied on galvanized steel","authors":"D. Leidlmair ,&nbsp;J. Duchoslav ,&nbsp;S. Keppert ,&nbsp;G. Mayr ,&nbsp;J.D. Pedarnig ,&nbsp;H. Groiss ,&nbsp;B. Strauß ,&nbsp;G.M. Wallner ,&nbsp;D. Stifter","doi":"10.1016/j.polymertesting.2025.108716","DOIUrl":"10.1016/j.polymertesting.2025.108716","url":null,"abstract":"<div><div>Depth-resolved analysis of organic coatings delivers crucial information on the interior material structure, <em>e.g.,</em> on the formation of chemical gradients or on the impact of degradation processes. However, assessing the complex internal composition of modern heterogeneous paint systems requires a careful selection of suitable depth profiling methods. In this work, a comparative examination of four state-of-the-art preparation techniques for depth-resolved analysis, exemplified on a high-build polyester-polyurethane coating system applied on galvanized steel, is reported. The fabrication of wedge-shaped tapers by applying mechanical polishing, cryo-ultra-low-angle microtomy (cryo-ULAM), a standardised paint borer, and Ar⁺-ion flat milling was comprehensively evaluated with respect to determining preparation artefacts including smearing, plastic deformation or alterations of the exposed internal coating chemistry induced by the different techniques. To this purpose, 3D topographical imaging, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were employed to examine the resulting surface morphology of extended sections down to the steel substrate, which showed the displacement of material for the paint borer sections, while the polished samples contained grooves and smearing artefacts. Furthermore, correlative elemental and chemical analysis by Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) allowed to determine the impact of the respective preparation process on the bulk and surface chemistry of the exposed areas, <em>e.g.</em>, the loss of chemical information after Ar⁺-ion flat milling. Overall, the fabrication of extended tapers for depth profiling by cryo-ULAM is favourably recommended by the comprehensive in-depth investigation performed in this study, which serves as a valuable basis for the future internal structure analysis of organic coatings.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108716"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137159","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}