Polymer Testing最新文献

{"title":"Thermo-optical and mechanical testing of high-refractive index omnidirectional polysiloxane hybrimers for optical encapsulation","authors":"Kyungkuk Koh,&nbsp;Younghun Kim,&nbsp;Honglae Sohn","doi":"10.1016/j.polymertesting.2026.109314","DOIUrl":"10.1016/j.polymertesting.2026.109314","url":null,"abstract":"<div><div>Conventional polysiloxane-based hybrid materials for LED encapsulation suffer from typically low refractive indices, limited optical transmittance, and extended cure times. Therefore, a systematic evaluation of curing behavior, mechanical hardness, refractive-index dispersion, optical transparency, thermal stability, and thermo-optical aging resistance is essential for assessing their applicability as optical encapsulants. To address these limitations, an omnidirectional polysiloxane hybrimer (OPH) was prepared by coupling phenyl-rich phenyl vinyl oligosiloxane (PVO) with omnidirectional cyclotetrasiloxane (OCS) through Pt-catalyzed hydrosilylation and was systematically tested as a high refractive-index optical encapsulant. Spectroscopic ellipsometry and thermogravimetric analysis confirmed that OPH exhibited high refractive indices of 1.64 at 450 nm, 1.61 at 520 nm, and 1.59 at 635 nm, together with a 5% weight-loss temperature (T₅%) of 352 °C. A controlled Si-H/vinyl ratio enabled the formulation to achieve 96.5% optical transmittance at 450 nm for 2 mm thick films and rapid thermal curing to a Shore D hardness of 82.5 within 1.5 h at 180 °C. DMA further showed that OPH exhibited a higher Tg (54 °C) and rubbery-region storage modulus (356 MPa) than the PSH system (37 °C and 183 MPa), supporting the formation of a more highly cross-linked and mechanically robust network. After thermal aging at 200 °C for 720 h, the transmittance at 450 nm decreased only from 96.5% to 95.5%, and the yellowness-index change remained as low as <span><math><mrow><mo>Δ</mo><mi>Y</mi><mi>I</mi></mrow></math></span> = 0.02, indicating strong thermo-optical and color stability under accelerated aging conditions. These results demonstrate that the OCS-based omnidirectional cross-linking strategy provides a favorable balance of refractive-index enhancement, optical transparency, curing efficiency, mechanical hardness, and thermo-optical durability, highlighting OPH as a promising material platform for optical encapsulation.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"161 ","pages":"Article 109314"},"PeriodicalIF":6.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148731334","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":"Corrigendum to “Study of mechanical and physical properties of pineapple leaf fiber and coffee husk filler reinforced polymer composite using response surface method” [Polym. Test. (2025) 108915]","authors":"Kinisa Wareso Abesho,&nbsp;Moera Gutu Jiru,&nbsp;Hirpa G. Lemu,&nbsp;Mohammed Abdulkadir Alfeki","doi":"10.1016/j.polymertesting.2026.109253","DOIUrl":"10.1016/j.polymertesting.2026.109253","url":null,"abstract":"","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"161 ","pages":"Article 109253"},"PeriodicalIF":6.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148731333","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":"Evaluation for thermal shock and hot-humid of material-extruded parts in additive manufacturing","authors":"Seungli Bae,&nbsp;Haeseong Jun,&nbsp;Ji Eun Lee,&nbsp;Yong Son,&nbsp;Seong Je Park","doi":"10.1016/j.polymertesting.2026.109308","DOIUrl":"10.1016/j.polymertesting.2026.109308","url":null,"abstract":"<div><div>Additive manufacturing (AM) is a technology that enables the direct fabrication of complex geometries from digital 3D data without molds or tooling, offering high design freedom and material efficiency. Among AM technologies, material extrusion (MEX) is widely utilized due to its low equipment cost, simple operation, and broad compatibility with various thermoplastics. However, to apply MEX components in the aerospace and automotive industries, it is essential to verify their reliability under harsh environmental conditions, such as rapid temperature changes and high temperature and humidity that may occur during actual operation. This study evaluates the environmental reliability of polymer specimens fabricated by the MEX process under thermal shock and hot–humid conditions. Bio-based polycarbonate (PC), PC, and acrylonitrile butadiene styrene (ABS) specimens were fabricated in both longitudinal and transverse orientations and subjected to environmental reliability tests. Tensile testing before and after exposure revealed numerically observed increases in tensile strength for most materials. In particular, the ABS specimen fabricated in the transverse direction exhibited statistically significant increases in tensile strength from 14.0 MPa to 24.1 MPa after thermal shock exposure and from 14.0 MPa to 26.7 MPa after hot–humid exposure. In addition, a drone body and wing components fabricated using ABS were assembled before and after the thermal shock test to evaluate application-level assembly reliability, confirming that the components maintained excellent assembly compatibility even after environmental exposure. Optical microscopy analysis confirmed that air gaps between deposited layers disappeared after exposure, resulting in a denser and smoother internal structure. These findings demonstrate that polymer components fabricated through the MEX process can maintain or even improve their mechanical reliability under combined thermal and moisture stresses. The results of this study are expected to serve as a key reference for establishing design and reliability evaluation standards for AM components operating in harsh environments.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"161 ","pages":"Article 109308"},"PeriodicalIF":6.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148642208","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":"Temperature-driven surface reorganization in hot-pressed CTMP sheets revealed by ToF-SIMS and chemometrics","authors":"Nivedhitha Venkatraman,&nbsp;Jutima Leksuntrakorn,&nbsp;Anders Brolin,&nbsp;Per Malmberg,&nbsp;Anette Larsson","doi":"10.1016/j.polymertesting.2026.109301","DOIUrl":"10.1016/j.polymertesting.2026.109301","url":null,"abstract":"<div><div>The surface chemistry of bio-based materials governs surface properties such as adhesion but can also be central to other functional properties such as dry and wet strength; however, how temperature-driven reorganization during processing occurs is not well understood. Laboratory-prepared, statically hot-pressed CTMP handsheets and industrially hot-pressed CTMP sheets were investigated to evaluate temperature-dependent surface reorganization. A comparison of ATR-FTIR and ToF-SIMS results showed that heat treatment induced chemical changes at the nanometer scale. Principal component analysis revealed systematic variation with temperature and sheet side, while orthogonal partial least squares-discriminant analysis and a shared-and-unique-structures plot isolated temperature-specific marker ions independent of front/back-side asymmetry. At 100 °C, the front-side is enriched in small carbohydrate- and lignin-derived fragments, sterols, and medium-chain fatty acid salts; at 200 °C, lignin-derived fragments and long-chain fatty acids are more abundant. Side controls show no systematic front/back-side differences, indicating a primarily temperature-driven effect. The observed temperature-dependent surface reorganization is attributed to moisture-assisted thermal softening, enhanced polymer-segment mobility, and redistribution of lignin-rich domains and extractives during hot pressing. The marker-set workflow provides an interface-sensitive approach for resolving temperature-driven surface reorganization in chemically heterogeneous lignocellulosic materials.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"161 ","pages":"Article 109301"},"PeriodicalIF":6.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148642209","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":"Surface engineering of carbon fibers via layer-by-layer graphene oxide grafting: Interface regulation and thermal conductivity enhancement of aligned continuous carbon fiber/natural rubber composites","authors":"Shuwei Zhao,&nbsp;Zhongzhe Gao,&nbsp;Zhiyuan Chen,&nbsp;Qunzhang Tu,&nbsp;Xinmin Shen,&nbsp;Qin Yin,&nbsp;Xiaocui Yang,&nbsp;Qing Liu,&nbsp;Fei Yang,&nbsp;Enshuai Wang,&nbsp;Wenqiang Peng,&nbsp;Ting Xu","doi":"10.1016/j.polymertesting.2026.109292","DOIUrl":"10.1016/j.polymertesting.2026.109292","url":null,"abstract":"<div><div>Natural rubber (NR) suffers from intrinsically low thermal conductivity and poor heat dissipation, which can be mitigated by constructing efficient heat transfer pathways using highly thermally conductive fillers. In this work, a three-dimensional thermally conductive network was developed within the NR matrix by synergistically incorporating polydopamine (PDA) and silane coupling agent co-modified ground carbon fibers (CF) together with oriented continuous CF grafted with graphene oxide (GO). This architecture significantly enhanced both the thermal conduction capability and interfacial performance of the composites. Specifically, PDA was first adsorbed onto CF surfaces as a secondary reaction platform, followed by coating with polyethyleneimine (PEI) via Michael addition. GO was subsequently grafted onto the fibers through electrostatic adsorption or acylation-based covalent bonding. Adding 1 phr GO(3)-CF (continuous CF with three electrostatically adsorbed GO layers) increased the thermal conductivity from 0.320 W/(m·K) to 0.383 W/(m·K) (19.7% rise), while GO-CF (covalently bonded with one GO layer) reached 0.394 W/(m·K) (23.1% rise). The thermal conductivity along the orientation direction of GO(3)-CF was 113.3% of the radial value. After 15 min of heating, the surface temperature of neat NR composites rose only from 32 °C to 59 °C, compared to 69.3 °C for GO(3)-CF/NR and 72.2 °C for GO-CF/NR. Pull-out forces of GO(3)-CF and GO-CF cords increased by 86.8% and 102.5% versus unmodified fibers, respectively, indicating reduced phonon scattering sites and lowered interfacial thermal resistance. Multiscale finite element simulations revealed the underlying mechanism, confirming that the enhancement effect of layer-by-layer self-assembly has a theoretical upper limit and does not increase indefinitely with the number of layers. These findings demonstrate the potential of such composites for applications in flexible thermal management, thermal protection, and heat dissipation.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"161 ","pages":"Article 109292"},"PeriodicalIF":6.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148657442","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":"Self-healing polyurethane elastomers based on boroxine ring/hydrogen bond dual dynamic networks: Preparation, properties, and molecular simulations","authors":"Jingguo Chen,&nbsp;Xinmin Shen,&nbsp;Qing Liu,&nbsp;Jiaojiao Zhang,&nbsp;Wenqiang Peng,&nbsp;Shuwei Zhao,&nbsp;Zhongzhe Gao,&nbsp;Qunzhang Tu,&nbsp;Ming Pan","doi":"10.1016/j.polymertesting.2026.109312","DOIUrl":"10.1016/j.polymertesting.2026.109312","url":null,"abstract":"<div><div>Self-healing polyurethane elastomers with dynamic crosslinking structures possess great potential for functional development. However, most existing studies focus on the regulation of macroscale properties, lacking in-depth microscopic analysis of crosslinked networks, which makes it challenging to elucidate the synergistic mechanism between mechanical and self-healing properties. Herein, modified polyurethane was used as the matrix, and tannic acid (TA) was introduced to construct PU-HPBA/TA self-healing elastomers crosslinked by a synergistic network of boroxine rings and multiple hydrogen bonds. Systematic studies were conducted by combining macroscale structural and property characterization with molecular dynamics (MD) simulations. The results show that TA can effectively optimize the crosslinked network. The sample with a TA content of 4.4 wt% exhibits the optimal mechanical properties, with a tensile strength of 9.22 ± 0.32 MPa, an elongation at break of 882.4 ± 47.6%, and a self-healing efficiency of 79.3 ± 3.2%, achieving a balance between structural stability and self-healing ability. MD simulations reveal dynamic evolution behaviors of three distinct hydrogen bond species at the microscopic level, confirming that PU-TA hydrogen bonds dominate the system, which provide microscopic insights into polyphenol-modified boron-based self-healing elastomers. This study provides a new strategy for the design of self-healing polyurethanes, and molecular simulations offer microscopic support for the mechanism research of dynamic bond self-healing systems, while expanding the application prospects of bio-based polyphenol-modified elastomers.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"161 ","pages":"Article 109312"},"PeriodicalIF":6.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148642213","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":"Substituent-induced torsional rigidity and isomeric ester geometry dictating the ultra-low dielectric constant and dissipation factor in polyimides","authors":"Jiyoung Kim,&nbsp;Chang Min Lee,&nbsp;Seokjin Lee,&nbsp;Seeun Jang,&nbsp;Hyunjin Park,&nbsp;Younhee Lim,&nbsp;Byung Hwa Seo,&nbsp;Tae Hoon Lee,&nbsp;Ki-Ho Nam","doi":"10.1016/j.polymertesting.2026.109315","DOIUrl":"10.1016/j.polymertesting.2026.109315","url":null,"abstract":"<div><div>Breaking the intrinsic trade-off between dielectric constant (<em>D</em>_k) and dielectric loss (<em>D</em>_f) in polymer dielectrics remains a central challenge in high-frequency material design. In this study, a molecular design framework is established to decouple <em>D</em>_k and <em>D</em>_f in poly(ester imide) (PEsI) systems by regulating torsional dynamics and dipole architecture simultaneously. Ortho-methyl substitution is introduced to impose torsional constraints along the imide backbone, while ester-isomer engineering enables precise modulation of dipole distribution and intermolecular packing through connectivity control. Combined experimental and computational analyses reveal that the dielectric response is governed not solely by fractional free volume but by the coupled interplay of packing efficiency, dipole orientation, and constrained chain dynamics. T–2MP exhibits a low <em>D</em>_k of 2.52 at 10 GHz, indicating an optimal balance between steric expansion and chain alignment. Further, copolymerization enables the independent tuning of dielectric parameters, yielding T–2MP/B (1:1) with an ultra-low <em>D</em>_f of 0.0022 and a <em>D</em>_k of 2.84. This behavior originates from the favorable ester geometry of BPTP, which promotes dense packing, reduces the dipole moment, and suppresses electronic polarization. All PEsI copolymers maintain high thermal stability (<em>T</em>_d5% &gt; 474 °C) and low thermal expansion (CTE &lt; 14.4 ppm K⁻¹). This work provides a generalizable molecular design strategy for overcoming the <em>D</em>_k–<em>D</em>_f trade-off in polymer dielectrics, offering a pathway toward high-performance materials for next-generation high-frequency electronics and advanced packaging.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"161 ","pages":"Article 109315"},"PeriodicalIF":6.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148731335","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":"Analysis of the induced microstructure of free-blown PET bottles after the elastic recovery","authors":"Luc Chevalier,&nbsp;Yun-Mei Luo,&nbsp;Evan Gargadennec","doi":"10.1016/j.polymertesting.2026.109310","DOIUrl":"10.1016/j.polymertesting.2026.109310","url":null,"abstract":"<div><div>The microstructure develops very rapidly in biaxially stretched PET above T_g and exhibits significant variability under supposedly identical processing conditions. This makes a deterministic prediction of the induced properties difficult and motivates the use of a probabilistic description. In this work, the microstructure of free-blown PET bottles after elastic recovery is investigated using DSC, density measurements and SAXS. The comparison between DSC- and density-based crystallinity estimates is first analyzed under reference-value uncertainty, rather than by imposing a unique crystallinity value. The results show that the apparent discrepancy between the two methods is strongly controlled by the crystalline density and by the enthalpy of fusion of fully crystalline PET. These reference quantities are therefore treated as uncertain physical inputs. The SAXS data are analyzed using both the lamellar stack fitting method and the correlation function γ(z). The γ(z) approach provides lamellar dimensions that are more consistent with the measured crystallinity range and with the observed mechanical anisotropy. A through-thickness microstructural description based on γ(z) is then introduced and used in a double homogenization analysis to predict the induced orthotropic elastic moduli. Particular attention is paid to the amorphous transverse modulus E_2a, whose partial indetermination is explicitly included in the uncertainty propagation. The results confirm the major role of the oriented or constrained amorphous phase in the final elastic anisotropy of free-blown PET bottles.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"161 ","pages":"Article 109310"},"PeriodicalIF":6.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148731337","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":"Corrigendum to “High-strength, transparent, and freeze-resistant PVA hydrogel enabled by microcrystal regulation” [Poly. Test. 159 (2026) 109210]","authors":"Yin Ke,&nbsp;Zhaohui Ling,&nbsp;Feng Zeng,&nbsp;Xiaofeng Liang,&nbsp;Zhiming Zhong,&nbsp;Ruohan Wang,&nbsp;Jin Xu,&nbsp;Xiaoling He","doi":"10.1016/j.polymertesting.2026.109252","DOIUrl":"10.1016/j.polymertesting.2026.109252","url":null,"abstract":"","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"161 ","pages":"Article 109252"},"PeriodicalIF":6.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148731322","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":"A characterization method for investigating the effectiveness of additives as odor adsorbents for plastic applications","authors":"Roxana Grömmer,&nbsp;Carl-Christoph Höhne","doi":"10.1016/j.polymertesting.2026.109309","DOIUrl":"10.1016/j.polymertesting.2026.109309","url":null,"abstract":"<div><div>Achieving a circular plastics economy depends strongly on effective plastic recycling. Mechanical recycling of post-consumer plastic waste plays a predominant role in this context. However, odors and volatile organic compounds (VOCs) present challenges for the recycling industry and threaten the quality and circularity of recycled plastics. One approach to tackle odor contamination is the use of adsorbents — porous materials that adsorb volatile substances. Various adsorbents, including zeolites and cyclodextrins, show promise for odor mitigation, but no universal solution exists across different recyclates. As a result, identifying a suitable adsorbent for a given recyclate remains a challenge. In this study, a rapid characterization method is presented to screen odor adsorbents directly on the additive, without any processing steps, for their effectiveness in removing VOCs from odor-contaminated plastics. The method was validated through internal laboratory repeatability and precision assessments, and proof of principle was demonstrated using a post-consumer polypropylene recyclate with four different adsorbents. Results reveal variations in VOC adsorption performance across adsorbents; notably, a synthetic zeolite achieved up to 80% VOC adsorption. The method enables rapid identification of promising adsorbents for VOC reduction and pre-evaluates candidates for further investigations.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"161 ","pages":"Article 109309"},"PeriodicalIF":6.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148642210","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}