IF 4.5 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-12-31 DOI: 10.1016/j.polymer.2025.129547

Ioannis Moutsios , Konstantinos Artopoiadis , Gkreti-Maria Manesi , Martin Rosenthal , Sergey V. Kravchenko , Dimitri A. Ivanov , Apostolos Avgeropoulos

Block copolymers (BCPs) are essential in nanotechnology due to their ability to self-assemble into well-defined nanostructures. In the context of structured liquids, a fundamental understanding of microphase behavior is key to the rational design of advanced soft-matter materials. This study investigates the phase behavior of viscoelastic poly (butadiene)-block-poly (dimethylsiloxane) (PB₁,₂-b-PDMS) copolymers, where PB segments exhibit 100 % 1,2-microstructure. We focus on how molecular parameters—such as block asymmetry, degree of polymerization, and segregation strength—govern the resulting morphology. In-situ small-angle X-ray scattering was employed to monitor real-time, temperature-dependent order–order and order–disorder transitions (ODT). Copolymers with low molecular weight values exhibited gradual loss of order, while intermediate ones underwent sharp ODT and high molecular weight systems preserved long-range order and structural orientation across wider temperature ranges. In all sequences the morphological behavior was impacted by the PDMS content. These findings provide new insight into the thermotropic self-assembly behavior of low-modulus, nanostructured BCPs and highlight their potential in applications such as soft lithography, flexible electronics, and neurointerfaces.

嵌段共聚物（bcp）在纳米技术中是必不可少的，因为它们能够自组装成定义良好的纳米结构。在结构液体的背景下，对微相行为的基本理解是合理设计先进软物质材料的关键。本研究研究了粘弹性聚（丁二烯）-嵌段聚（二甲基硅氧烷）（pb1,2 -b- pdms）共聚物的相行为，其中PB段呈现100% 1,2微观结构。我们关注的是分子参数——如嵌段不对称、聚合程度和分离强度——如何控制最终的形态。原位小角x射线散射用于实时监测与温度相关的有序-有序和有序-无序转变（ODT）。低分子量共聚物的有序度逐渐下降，而中等分子量共聚物的ODT急剧下降，而高分子量共聚物在较宽的温度范围内保持了长期的有序度和结构取向。所有序列的形态行为均受PDMS含量的影响。这些发现为低模量、纳米结构bcp的热致自组装行为提供了新的见解，并突出了它们在软光刻、柔性电子和神经接口等应用中的潜力。

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引用次数: 0

Hierarchical alignment of nanophase separation in TPU/cellulose nanocrystal composite fibers via electrospinning: A pathway to enhanced mechanical performance 静电纺丝对TPU/纤维素纳米晶复合纤维中纳米相分离的层次排列：提高机械性能的途径

IF 4.5 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-12-30 DOI: 10.1016/j.polymer.2025.129544

Wonchalerm Rungswang , Phendaow Jiamjirangkul , Dechmongkhon Kaewsuwan , Siriwat Soontaranon , Supagorn Rugmai , Autchara Pangon

This study provides an in-depth structural analysis of hard-segment (HS) nanodomains in thermoplastic polyurethane (TPU) and TPU/cellulose nanocrystal (CNC) electrospun nanofibers and directly correlates nanoscale morphology with macroscopic mechanical performance. CNCs (0–5 wt%) were incorporated into TPU via electrospinning at take-up velocities of 440 and 1320 m/min. Synchrotron-based small-angle X-ray scattering (SAXS), interpreted through a hierarchical lamellar grain model, revealed two distinct morphologies: oriented lamellae and fragmented “oblique-herringbone” structures. At low draw speed, CNCs acted as structural templates promoting preferential domain orientation, whereas high draw speed induced fragmentation regardless of CNC content. Quantitative SAXS analysis identified systematic variations in lamellar long period, grain width (IB_σ), and grain tilt (ϕ) with CNC addition, with optimal domain dimensions achieved at 3 wt% CNC. These structural parameters directly reflected changes in tensile performance: the widest lamellar grains corresponded to peak tensile strength, while increased domain orientation and packing density enhanced modulus. This integration of nanodomain mapping and mechanical analysis establishes a clear structure–property relationship and offers a framework for tuning performance in sustainable, high-strength TPU-based nanofibers.

本研究对热塑性聚氨酯（TPU）和TPU/纤维素纳米晶（CNC）静电纺纳米纤维中的硬段（HS）纳米结构域进行了深入的结构分析，并将纳米尺度形貌与宏观力学性能直接联系起来。以440米/分钟和1320米/分钟的吸丝速度，通过静电纺丝将cnc （0-5 wt%）掺入TPU。基于同步加速器的小角度x射线散射（SAXS），通过分层片层颗粒模型解释，揭示了两种不同的形态：定向片层和破碎的“斜人字形”结构。在低拉伸速度下，CNC作为结构模板促进优先畴取向，而高拉伸速度导致碎片化，无论CNC含量如何。定量SAXS分析发现，随着CNC的加入，片层长周期、晶粒宽度（IBσ）和晶粒倾角（ϕ）发生了系统变化，在CNC为3 wt%时达到了最佳域尺寸。这些结构参数直接反映了拉伸性能的变化：最宽的片层晶粒与峰值拉伸强度相对应，而增加的畴取向和堆积密度提高了模量。这种纳米域映射和力学分析的集成建立了清晰的结构-性能关系，并为可持续的高强度tpu基纳米纤维的性能调整提供了框架。

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引用次数: 0

Linear copolymerized polyurethane with variable mechanical and hydrophobic properties for electrospun fibrous membranes 电纺丝纤维膜用具有可变力学和疏水性的线状共聚聚氨酯

IF 4.5 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-12-30 DOI: 10.1016/j.polymer.2025.129545

Jialin Yang, Jiahao Li, Xinyu Liu, Jiaoyan Ai, Lina Song, Baohua Liu

Flexible, hydrophobic and breathable fibrous membranes are ideal materials for wide applications. However, conventional membrane materials, such as melt-spun polyester and expanded polytetrafluoroethylene (ePTFE), have inherent limitations. The structure of polyurethane (PU) imparts excellent mechanical properties and versatile functionality, making it an ideal candidate for such membranes. In this study, a series of linear copolymerized CO₂-based polyurethane solutions were synthesized using poly (propylene carbonate) diol (PPCD) and poly (tetramethylene ether) glycol (PTMG) as composite soft segments. The mechanical properties of PU films were altered by changing the ratio of PPCD/PTMG. An optimal ratio of 40:7 yielding a tensile strength of 53 MPa and elongation at break of 770 %. Building upon these optimized formulations, the obtained PUs were then used to prepare nanofibrous membranes by electrospinning. At high solution viscosity (∼10,500 mPa s), precise control of molecular weight and solution concentration proved critical for obtaining uniform, defect-free electrospun membranes. These optimized membranes exhibited an increased tensile strength, reaching 6.35 MPa. Furthermore, the electrospun membranes exhibited excellent surface hydrophobicity, with a static water contact angle (WCA) reaching up to 120.7°. This study provides a novel strategy for the application of linear copolymerized CO₂-based PU in electrospun fibrous membranes and explores the synergistic optimization of mechanical and hydrophobic properties through integrated chemical structure design and process control.

柔韧、疏水、透气的纤维膜是广泛应用的理想材料。然而，传统的膜材料，如熔融纺聚酯和膨胀聚四氟乙烯（ePTFE），具有固有的局限性。聚氨酯（PU）的结构赋予了优异的机械性能和多功能，使其成为这种膜的理想候选者。本研究以聚碳酸酯二醇（PPCD）和聚四亚甲基醚乙二醇（PTMG）为复合软段，合成了一系列co2基线性共聚聚氨酯溶液。通过改变PPCD/PTMG的配比，改变了PU膜的力学性能。最佳配比为40:7，抗拉强度为53mpa，断裂伸长率为770%。在此基础上，利用静电纺丝法制备了纳米纤维膜。在高溶液粘度（~ 10,500 mPa·s）下，精确控制分子量和溶液浓度对于获得均匀、无缺陷的静电纺丝膜至关重要。优化后的膜抗拉强度提高，达到6.35 MPa。静电纺丝膜具有良好的表面疏水性，静水接触角（WCA）可达120.7°。本研究为co2基线性共聚PU在电纺丝纤维膜中的应用提供了一种新的策略，并通过化学结构设计和工艺控制的集成，探索了机械性能和疏水性能的协同优化。

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引用次数: 0

Micro-macro cross-scale mechanism of creep behavior in PVC under hygrothermal aging: A combined molecular dynamics and finite element simulation approach 湿热老化下聚氯乙烯蠕变行为的微观宏观跨尺度机制：分子动力学与有限元模拟相结合的方法

IF 4.5 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-12-30 DOI: 10.1016/j.polymer.2025.129546

Hui Li , Xiaoxiao Su , Guan Gong , Aoxin Shao

The degradation of creep performance in polyvinyl chloride (PVC) under high-temperature and high-humidity conditions significantly compromises its long-term service safety. In this study, a multi-scale simulation approach integrating molecular dynamics (MD) and finite element analysis (FEA) was employed to systematically investigate the influence of varying simulation durations (0.5 ns–3 ns, representing different stages of structural evolution) on the creep behavior of rigid PVC at 60 °C and 90 %RH. MD simulation results reveal that, as aging progresses, water molecule diffusion induces a non-monotonic evolution in the mobility of PVC molecular chains (quantified by mean square displacement, MSD) and fractional free volume (FFV), characterized by an initial decrease followed by a subsequent increase. Concurrently, Cl–Cl inter-chain interactions weaken, the glass transition temperature (Tg) declines, and Young's modulus E decreases from 1.80 GPa to 1.55 GPa. Furthermore, finite element simulations demonstrate that macroscopic creep strain predictions—based on these microscale parameters—exhibit strong agreement with experimental data, indicating that stress levels and aging extent exert a synergistic effect in accelerating creep deformation. This work elucidates the mechanistic transition of water molecules during hydrothermal aging: from initially acting as agents promoting structural relaxation to later functioning as disruptors of inter-chain interactions, thereby driving the morphological transformation of PVC from densification to network loosening. A cross-scale correlative model linking water molecule penetration to macroscopic creep response is established, offering a robust theoretical foundation for performance assessment and lifetime prediction of PVC materials in hydrothermal environments.

聚氯乙烯（PVC）在高温高湿条件下蠕变性能的退化严重影响了其长期使用安全性。本研究采用分子动力学（MD）和有限元分析（FEA）相结合的多尺度模拟方法，系统研究了不同模拟时间（0.5 ns - 3 ns，代表结构演变的不同阶段）对刚性PVC在60°C和90% RH下蠕变行为的影响。MD模拟结果表明，随着老化的进行，水分子的扩散导致PVC分子链的迁移率（均方位移，MSD）和分数自由体积（FFV）呈非单调演化，其特征是先降低后升高。同时，Cl-Cl链间相互作用减弱，玻璃化转变温度（Tg）下降，杨氏模量E从1.80 GPa降低到1.55 GPa。此外，有限元模拟表明，基于这些微观参数的宏观蠕变应变预测与实验数据非常吻合，表明应力水平和时效程度在加速蠕变变形方面具有协同效应。这项工作阐明了水分子在热液老化过程中的机制转变：从最初作为促进结构松弛的剂到后来作为链间相互作用的干扰物，从而推动PVC从致密到网络松动的形态转变。建立了水分子渗透与宏观蠕变响应的跨尺度关联模型，为热液环境下PVC材料的性能评估和寿命预测提供了坚实的理论基础。

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引用次数: 0

Evaluations of rubber seal materials in a vacuum suction pad for automated mooring systems against ozone-induced degradations 用于自动系泊系统的真空吸垫橡胶密封材料抗臭氧诱导降解的评价

IF 4.5 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-12-29 DOI: 10.1016/j.polymer.2025.129538

Yeonhong Son , Won-Seok Kim , Sieun Jang , Yongjin Kim , Daewon Seo , Hwasup Jang , Songkil Kim

This study evaluates the ozone-induced degradation of chloroprene rubber (CR 100%), natural rubber (NR 100%), and CR 40%:NR 60% blend through an integrated experimental and finite element (FE) modeling approach. Accelerated ozone aging was employed to represent severe marine environments, followed by mechanical, surface, and chemical characterization. Distinct degradation pathways were identified: NR underwent extensive chain scission accompanied by macroscopic fissuring, whereas CR exhibited superior chemical stability with only minor oxidative crosslinking. Notably, CR 40%:NR 60% exhibited a distinct protective effect, in which the CR phase mitigated NR-driven degradation and effectively suppressed crack propagation under oxidative conditions. These experimentally observed chemical and mechanical trends were incorporated into a Yeoh hyperelastic model to evaluate suction performance via FE simulations. The numerical results indicate that CR 40%:NR 60% maintains a high post-aging reaction force (85.6 kN), reflecting a favorable balance between ozone-induced stiffening and preserved contact compliance. Overall, this study establishes a practical framework linking material formulation to functional sealing reliability, providing design-relevant insights for elastomeric seals in automated mooring systems.

本研究通过综合实验和有限元（FE）建模方法，评估了氯丁橡胶（CR 100%）、天然橡胶（NR 100%）和CR 40%:NR 60%共混物的臭氧诱导降解。采用加速臭氧老化来表示恶劣的海洋环境，其次是机械、表面和化学表征。发现了不同的降解途径：NR发生广泛的链断裂并伴有宏观断裂，而CR表现出优异的化学稳定性，仅发生轻微的氧化交联。值得注意的是，CR 40%:NR 60%表现出明显的保护作用，其中CR相减轻了NR驱动的降解，有效地抑制了氧化条件下的裂纹扩展。这些实验观察到的化学和力学趋势被纳入到Yeoh超弹性模型中，通过有限元模拟来评估吸力性能。数值结果表明，CR 40%:NR 60%保持了较高的时效后反作用力（85.6 kN），反映了臭氧诱导硬化和保持接触柔度之间的良好平衡。总的来说，本研究建立了一个实用的框架，将材料配方与功能密封可靠性联系起来，为自动系泊系统中的弹性密封提供了设计相关的见解。

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引用次数: 0

Improving the friction and wear performance of polyimide fiber by constructing a TiO2/PTFE composite shell on the fiber surface 通过在聚酰亚胺纤维表面构建TiO2/PTFE复合壳层，提高聚酰亚胺纤维的摩擦磨损性能

IF 4.5 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-12-29 DOI: 10.1016/j.polymer.2025.129542

Yuelin Jin , Li Wang , Tao Cai , Hongjie Xu , Jiayu Zhan , Shengli Qi , Guofeng Tian , Dezhen Wu

This study introduces an ion-exchange enhanced adsorption method to create a titanium dioxide (TiO₂)/polytetrafluoroethylene (PTFE) composite shell on polyimide (PI) fibers, improving their friction and wear performance. PTFE's low coefficient of friction reduces fiber friction when applied to PI fiber surface. Introducing TiO₂ improves the uniformity of the PTFE coating, further lowering the friction coefficient. The maximum reduction in the coefficient of friction of the PI/TiO₂/PTFE composite fiber was 46 %. During wear, PTFE forms a lubricating transfer film on the fiber wear interface, increasing wear resistance. TiO₂ particles within the transfer film as a high-hardness filler, reinforcing the film and further improving fiber wear properties. The PI/TiO₂/PTFE composite fiber achieved 1782 cycles to failure, approximately 300 times greater than the original fiber. Importantly, the composite fiber's mechanical properties, surface energy, and interfacial bonding strength remain comparable to those of the original fiber. This approach offers a highly efficient method for enhancing PI fiber's friction and wear properties, expanding its potential applications.

本研究采用离子交换增强吸附法在聚酰亚胺（PI）纤维上制备二氧化钛(TiO2)/聚四氟乙烯（PTFE）复合壳，提高其摩擦磨损性能。聚四氟乙烯的低摩擦系数减少纤维摩擦时，应用于PI纤维表面。TiO2的加入提高了PTFE涂层的均匀性，进一步降低了摩擦系数。PI/TiO2/PTFE复合纤维的摩擦系数最大降低46%。在磨损过程中，PTFE在纤维磨损界面上形成润滑传递膜，提高耐磨性。TiO2颗粒在转移膜内作为高硬度填料，增强了转移膜，进一步提高了纤维的耐磨性能。PI/TiO2/PTFE复合纤维达到1782次循环失效，大约是原始纤维的300倍。重要的是，复合纤维的机械性能、表面能和界面结合强度与原始纤维相当。这种方法为提高PI纤维的摩擦磨损性能提供了一种高效的方法，扩大了其潜在的应用范围。

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引用次数: 0

Fracture toughness and bonding strengths of epoxy composites containing POSS-PCLn: An impact of phase separation from macro-to nano-scales 含POSS-PCLn环氧复合材料的断裂韧性和结合强度：宏观到纳米尺度相分离的影响

IF 4.5 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-12-29 DOI: 10.1016/j.polymer.2025.129541

Gaoming Li , Yeping Wu , Guohua Hang , Xibing Shen , Zhongtao Chen , Mao Chen , Xiuli Zhao , Yinyu Zhang , Sixun Zheng

Epoxy thermosets have been widely used in engineering applications due to their excellent thermal stability and chemical resistance. However, their inherent brittleness causes low bonding strength. Therefore, improvement of toughness is required. By using a variety of modifiers, epoxy thermosets can be toughened via the generation of fine phase-separated morphologies. In this work, we reported the toughening of epoxy thermosets with polyhedral oligomeric silsesquioxane (POSS)-capped poly(ε-caprolactone)s (PCL). By taking control of types of R groups (i.e., isobutyl and/or isooctyl) of POSS cages and the lengths of PCL chains, the epoxy thermosets were regulated with the morphologies from nano-to macro-scales. It was found that the improvement of toughness was quite dependent on types of R groups of POSS cages. Under the identical condition, the thermosets contain isooctyl POSS-PCL_n had the fracture toughened larger than those containing isobutyl POSS groups. For the thermoset containing 15 wt% of isooctyl POSS-PCL_1.00, the critical stress intensity factor (K_IC) was enhanced from 0.70 to 1.69 MPa m^1/2 at room temperature and from 1.11 to 2.51 MPa m^1/2 at low temperature and the thermal stability remained invariant. Furthermore, the bonding strength on stainless steel and anodized aluminum substrates were significantly improved with the incorporation of 15 wt% of isooctyl POSS-PCL_1.00. These findings provide a novel approach to regulate phase structure in epoxy thermosets, offering the insights into structure-performance relationships, thus opening up a new way for designing epoxy resins with high toughness and adhesive strength.

环氧热固性材料以其优异的热稳定性和耐化学性在工程中得到了广泛的应用。然而，它们固有的脆性导致了较低的结合强度。因此，需要提高韧性。通过使用多种改性剂，环氧热固性树脂可以通过产生精细的相分离形态来增韧。在这项工作中，我们报道了用多面体低聚硅氧烷（POSS）包封聚（ε-己内酯）s （PCL）增韧环氧热固性树脂。通过控制POSS笼的R基团类型（即异丁基和/或异辛基）和PCL链的长度，可以从纳米到宏观尺度上调控环氧热固性。结果表明，POSS网箱的韧性提高程度与R组类型有很大关系。在相同条件下，含有异辛基POSS- pcln基团的热固性材料的断口增韧程度大于含有异丁基POSS基团的热固性材料。对于含有15 wt%异辛基POSS-PCL1.00的热固性材料，室温下临界应力强度因子（KIC）从0.70提高到1.69 MPa m1/2，低温下从1.11提高到2.51 MPa m1/2，热稳定性保持不变。此外，加入15%的异辛基POSS-PCL1.00后，不锈钢和阳极氧化铝基板的结合强度显著提高。这些发现提供了一种新的方法来调节环氧热固性树脂的相结构，提供了对结构-性能关系的见解，从而为设计具有高韧性和粘接强度的环氧树脂开辟了新的途径。

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引用次数: 0

Regulation of pore formation and crystalline phase alignment in melt-processed PFA films via biaxial stretching 通过双轴拉伸调节熔融加工PFA薄膜的孔隙形成和结晶相排列

IF 4.5 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-12-29 DOI: 10.1016/j.polymer.2025.129536

Ho Jin Jung , Gyeong Min Choi , Young Je Kwon , Dong Jun Han , Kaiyun Zhang , Jun Young Cheong , Min Wook Pin , Jeong-Gu Yeo , Hoik Lee , Kie Yong Cho

Fluorinated polymers such as polytetrafluoroethylene (PTFE) offer outstanding chemical resistance and mechanical stability, yet their poor processability has limited their adoption in air filtration and separator applications. Here, we report perfluoroalkoxy alkane (PFA) films as promising HEPA-filter media via biaxial stretching. Owing to their high melt processability, PFA resins can be extruded into films and subsequently stretched in a controlled manner to generate uniform pores. By tuning stretching temperature, rate, and stretching ratio, crystalline lamellae were aligned while the interlamellar amorphous phase underwent cavitation (voiding), yielding well-defined porous architectures. Structural and morphological evolution was characterized by SEM, WAXS, and Raman spectroscopy, together with mechanical and thermal analyses. The stretched films exhibited tunable pore sizes, and filtration efficiency and pressure drop were benchmarked against conventional polymeric materials. Notably, films stretched at 250 °C and 0.1 mm s⁻¹ exhibited a narrow pore-size distribution and superior air filtration performance. These results indicate that biaxially stretched PFA films unite stability, processability, and high performance, underscoring their potential as next-generation high-efficiency particulate air (HEPA) media. More broadly, this work elucidates pore formation via crystalline-orientation control in fluoropolymers and expands their applicability in advanced air-filtration technologies.

聚四氟乙烯（PTFE）等氟化聚合物具有出色的耐化学性和机械稳定性，但其加工性差限制了其在空气过滤和分离器应用中的应用。在这里，我们报道了全氟烷氧基烷烃（PFA）薄膜通过双轴拉伸作为有前途的hepa过滤介质。由于其高熔体加工性，PFA树脂可以挤压成薄膜，随后以受控的方式拉伸，以产生均匀的孔隙。通过调整拉伸温度、速率和拉伸比，晶体片层排列整齐，而片层间非晶相发生空化（空化），产生明确的多孔结构。通过SEM， WAXS，拉曼光谱以及力学和热分析对结构和形态演化进行了表征。拉伸膜具有可调节的孔径，过滤效率和压降与传统聚合物材料为基准。值得注意的是，薄膜在250°C和0.1 mm s−1拉伸时表现出狭窄的孔径分布和优越的空气过滤性能。这些结果表明，双轴拉伸PFA薄膜具有稳定性、可加工性和高性能，强调了它们作为下一代高效微粒空气（HEPA）介质的潜力。更广泛地说，这项工作阐明了通过晶体取向控制氟聚合物的孔隙形成，并扩大了它们在先进空气过滤技术中的适用性。

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引用次数: 0

Establishment of a quantitative mathematical model with expressive formulation based on the basic laws and physical essences of bubble growth in polymer foaming 根据聚合物发泡过程中气泡生长的基本规律和物理本质，建立了具有表达式的定量数学模型

IF 4.5 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-12-29 DOI: 10.1016/j.polymer.2025.129543

Tuanhui Jiang , Jingfu Xing , Xiangbu Zeng , Shengnan Li , Xiaodie Zhang , Chun Zhang , Li He , Wei Gong

Understanding and predicting bubble growth is fundamental to controlling the cellular structure of polymer foams. Over the past five decades, researchers have combined experimental and theoretical approaches to investigate bubble growth behavior. However, existing models fail to clearly elucidate the physical essence of bubble growth and often exhibit significant deviations when quantitatively validated against experimental data. Firstly, based on classical thermodynamic principles, we proposed that bubble formation in polymer melts required simultaneous satisfaction of both mechanical and phase equilibrium conditions. The three fundamental physical assumptions were proposed for establishing a mathematical model describing the bubble diameter evolution over time (D-t model): (1) The bubble diameter is inversely proportional to the final bubble density. (2) Employing the Logistic function to describe mechanical equilibrium dominated by gas molecular fluctuations. (3) The Boltzmann function is utilized to characterize the transport of gas molecules driven by chemical potential difference. Through mathematical simulation of bubble growth with different diameters and bubble growth nucleated at the same time during polypropylene chemical foaming injection molding, it has been revealed that the randomness and non-uniformity in the microscopic distribution and aggregation of gas are the primary factors influencing the differences in bubble diameter. The quantitative accuracy of the model was further validated across diverse polymer systems and processing conditions. This work not only offers a novel understanding of the physical essence of bubble growth but also provides an effective theoretical tool for the quantitative analysis and process optimization of polymer foaming processes.

了解和预测泡沫的生长是控制聚合物泡沫的细胞结构的基础。在过去的五十年里，研究人员将实验和理论方法结合起来研究气泡的生长行为。然而，现有的模型不能清楚地阐明气泡生长的物理本质，并且在与实验数据进行定量验证时经常出现显着偏差。首先，基于经典热力学原理，我们提出聚合物熔体中气泡的形成需要同时满足力学和相平衡条件。为建立描述气泡直径随时间演化的数学模型（D-t模型），提出了三个基本的物理假设：(1)气泡直径与最终气泡密度成反比。(2)采用Logistic函数描述以气体分子波动为主导的力学平衡。(3)利用玻尔兹曼函数表征化学位差驱动下气体分子的输运。通过对聚丙烯化学发泡注射成型过程中不同直径气泡生长和同时成核气泡生长的数学模拟，揭示了气体微观分布和聚集的随机性和非均匀性是影响气泡直径差异的主要因素。该模型的定量准确性在不同的聚合物体系和加工条件下得到了进一步验证。这项工作不仅对气泡生长的物理本质有了新的认识，而且为聚合物发泡过程的定量分析和工艺优化提供了有效的理论工具。

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引用次数: 0

Fabrication and finite element analysis of variable-sensitivity force sensor using structural modification and stiffness change of shape-memory polymer 基于形状记忆聚合物结构修饰和刚度变化的变灵敏度力传感器制作及有限元分析

IF 4.5 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-12-28 DOI: 10.1016/j.polymer.2025.129537

Sourav Roy , Taichi Taniguchi , Kazuto Takashima

Force sensors (FSs) in caregiving and rehabilitation applications need to be lightweight, flexible and capable of adapting within dynamic environments. Therefore, by leveraging the unique thermo-responsive stiffness-tunable properties of shape-memory polymer (SMP), we previously proposed FSs with variable sensitivity and measuring range by taking advantage of stiffness change, structural modification and programming in cross-sectional area. In this work, we have combined the concept of our preliminarily developed FS and presented a novel structure of the adaptable polyurethane SMP-FS consisting of center and flap sections. We have employed inbuilt titanium wires to heat the sensor above the glass transition temperature (

T_{g}

= 45 °C) and soften it, allowing us to change the bending shape automatically. A steel shim plate is also bonded to the center section for attaching a strain gauge. The notable difference in the slope of the “Force vs. deformation and strain” profile, as determined by linear regression at both the initial and bent positions and above and below

T_{g}

, indicates that the sensitivity of this FS can be varied by adjusting its cross-section and stiffness. The experimental measurements positively demonstrate about 3.3 times improvement in sensitivity for our proposed prototype at modified cross-sectional state than the initial shape. Several other critical performance metrics like hysteresis, non-linearity, and long-term stability (slope and baseline strain drift) are also presented and quantified at all configurations (ORIGIN, BENT 1, BENT 2) and temperatures. They are found to have within acceptable limit for soft sensing field. Furthermore, we have theoretically validated the experimental data by implementing finite element analysis of the SMP-FS geometries. The evidence observed from the trend of deformation responses and change in sensitivities both at below and above

T_{g}

have suggested acceptable accuracy of our experimental approach.

在护理和康复应用中的力传感器（FSs）需要重量轻，灵活，能够适应动态环境。因此，我们利用形状记忆聚合物（SMP）独特的热响应刚度可调特性，利用刚度变化、结构修改和截面积编程，提出了具有可变灵敏度和测量范围的FSs。在这项工作中，我们结合了我们初步开发的FS概念，提出了一种由中心和皮瓣部分组成的适应性聚氨酯SMP-FS的新结构。我们采用内置钛丝将传感器加热到玻璃化转变温度（Tg = 45°C）以上并使其软化，使我们能够自动改变弯曲形状。钢垫片也粘合在中心部分，用于附加应变计。在初始和弯曲位置以及在Tg以上和以下的线性回归中确定的“力与变形和应变”剖面的斜率的显着差异表明，该FS的灵敏度可以通过调整其截面和刚度来改变。实验测量结果表明，在修正截面状态下，我们提出的原型的灵敏度比初始形状提高了3.3倍。其他几个关键的性能指标，如迟滞、非线性和长期稳定性（斜率和基线应变漂移）也在所有配置（ORIGIN、BENT 1、BENT 2）和温度下被提出和量化。发现它们在软测量领域的可接受范围内。此外，我们还通过对SMP-FS几何形状进行有限元分析，从理论上验证了实验数据。从变形响应的趋势和灵敏度在低于和高于Tg时的变化中观察到的证据表明，我们的实验方法具有可接受的准确性。

{"title":"Fabrication and finite element analysis of variable-sensitivity force sensor using structural modification and stiffness change of shape-memory polymer","authors":"Sourav Roy , Taichi Taniguchi , Kazuto Takashima","doi":"10.1016/j.polymer.2025.129537","DOIUrl":"10.1016/j.polymer.2025.129537","url":null,"abstract":"<div><div>Force sensors (FSs) in caregiving and rehabilitation applications need to be lightweight, flexible and capable of adapting within dynamic environments. Therefore, by leveraging the unique thermo-responsive stiffness-tunable properties of shape-memory polymer (SMP), we previously proposed FSs with variable sensitivity and measuring range by taking advantage of stiffness change, structural modification and programming in cross-sectional area. In this work, we have combined the concept of our preliminarily developed FS and presented a novel structure of the adaptable polyurethane SMP-FS consisting of center and flap sections. We have employed inbuilt titanium wires to heat the sensor above the glass transition temperature (<span><math><mrow><msub><mi>T</mi><mi>g</mi></msub></mrow></math></span> = 45 °C) and soften it, allowing us to change the bending shape automatically. A steel shim plate is also bonded to the center section for attaching a strain gauge. The notable difference in the slope of the “Force vs. deformation and strain” profile, as determined by linear regression at both the initial and bent positions and above and below <span><math><mrow><msub><mi>T</mi><mi>g</mi></msub></mrow></math></span>, indicates that the sensitivity of this FS can be varied by adjusting its cross-section and stiffness. The experimental measurements positively demonstrate about 3.3 times improvement in sensitivity for our proposed prototype at modified cross-sectional state than the initial shape. Several other critical performance metrics like hysteresis, non-linearity, and long-term stability (slope and baseline strain drift) are also presented and quantified at all configurations (ORIGIN, BENT 1, BENT 2) and temperatures. They are found to have within acceptable limit for soft sensing field. Furthermore, we have theoretically validated the experimental data by implementing finite element analysis of the SMP-FS geometries. The evidence observed from the trend of deformation responses and change in sensitivities both at below and above <span><math><mrow><msub><mi>T</mi><mi>g</mi></msub></mrow></math></span> have suggested acceptable accuracy of our experimental approach.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"344 ","pages":"Article 129537"},"PeriodicalIF":4.5,"publicationDate":"2025-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145845428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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