Polymer Testing最新文献_第9页

A green approach for the preparation of antibacterial polylactide fabric via radiation-induced graft polymerization and copper complexation 辐射诱导接枝聚合和铜络合制备抗菌聚乳酸织物的绿色途径

IF 6 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Polymer Testing

Pub Date : 2025-10-13 DOI: 10.1016/j.polymertesting.2025.109003

In-Tae Hwang , Eunchong Shin , Joon-Yong Sohn , Junhwa Shin , Jong-Hyun Jung , Seok-Yun Jeong , Seunghee Bae , Kwanwoo Shin , Chan-Hee Jung

Herein, we newly developed an eco-friendly and efficient strategy for antibacterial modification of PLA fabrics that facilitates manufacturing processing in an all-aqueous solution and ensures antibacterial activity without significant deterioration of the mechanical strength. The PLA fabrics were efficiently modified with covalent bonding through electron beam (EB)-induced aqueous graft polymerization of acrylic acid (AA) in the presence of a poly(ethylene glycol) diacrylate (PEGDA) crosslinker and then complexed with antibacterial copper (Cu) ions (PLA-g-cPAA-Cu). The addition of the PEGDA crosslinker (0.6 wt%) to the graft polymerization led to a nearly twofold increase in the grafting degree from 50 to 91 % in the water solvent in comparison to in the absence of PEGDA. The resulting grafted fabric also showed minimal deterioration of mechanical strength. It was further found that the hydrophilic PEGDA-crosslinked PAA-Cu complexes were incorporated mainly onto the surfaces of the fiber constituents, preserving the porous structure of the PLA fabric. The prepared PLA-g-cPAA-Cu fabrics with a grafting degree of above 20 % showed excellent contact-killing ability of 99.9 % for Gram-negative E. coli and Gram-positive S. aureus within 3 h and cell viability of above 90 % in a WST-1 cytotoxicity assay using a skin cell line, HaCaT. Moreover, the PLA-g-cPAA-Cu fabric with a grafting degree of 20 % was more than 90 % enzymatically degraded after 90 days. The obtained results unequivocally demonstrate that this EB-based functionalization strategy is not only environmentally friendly and efficient, but also yields PLA-based PPEs with exceptional antibacterial activity, good biodegradability, and suitable mechanical strength.

在此，我们新开发了一种环保高效的PLA织物抗菌改性策略，使其易于在全水溶液中制造加工，并确保抗菌活性而不会显著降低机械强度。在聚乙二醇二丙烯酸酯（PEGDA）交联剂的存在下，通过电子束（EB）诱导丙烯酸（AA）的水接枝聚合，再与抗菌铜（Cu）离子（PLA-g- cpaa -Cu）络合，对PLA织物进行了共价键改性。在接枝聚合中加入PEGDA交联剂（0.6 wt%），接枝度在水溶剂中增加了近两倍，从50%增加到91%，而在没有PEGDA的情况下。所得到的接枝织物也显示出最小的机械强度退化。进一步发现亲水性pegda交联PAA-Cu配合物主要结合在纤维组分的表面，保留了PLA织物的多孔结构。接枝度在20%以上的PLA-g-cPAA-Cu织物在3 h内对革兰氏阴性大肠杆菌和革兰氏阳性金黄色葡萄球菌的接触杀灭能力达到99.9%，在皮肤细胞系HaCaT的WST-1细胞毒性实验中，细胞存活率达到90%以上。接枝度为20%的PLA-g-cPAA-Cu织物在90 d后酶降解率达到90%以上。所获得的结果明确表明，这种基于eb的功能化策略不仅环保高效，而且生产出具有优异抗菌活性、良好生物降解性和合适机械强度的pla基ppe。

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引用次数: 0

The impact of polyurethane adhesives on the recyclability of polyethylene-based laminated films 聚氨酯胶粘剂对聚乙烯基复合薄膜可回收性的影响

IF 6 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Polymer Testing

Pub Date : 2025-10-13 DOI: 10.1016/j.polymertesting.2025.109010

Ali Ebrahimi , Francis Pardal , Marion Jarnoux , Marc Defoin , Livia Mesquita Dias Loiola , Kim Ragaert , Rudinei Fiorio

Laminated plastic films, especially mono-material multilayer polyethylene-based (MM-PE) films, have attracted strong interest within the packaging industry over the past decade. Towards closing the material loop, MM-PE films should be recycled in a film-to-film mechanical recycling process, while preserving their desired performance. However, MM-PE laminates typically contain polyurethane (PUR) adhesives between PE film layers, which can affect their recyclability. Herein, three MM-PE films containing different PUR adhesives were studied to assess the effect of the PUR characteristics on the films’ recyclability. The processability of MM-PE laminated films produced via film-blowing extrusion was evaluated, followed by structural, rheological, mechanical, and optical characterization of the recycled films. The composition of the PUR adhesive substantially affects the closed-loop recyclability of the films, and even a small PUR content (2 wt%) can hinder the recycling process. Overall, PUR adhesives reduce the zero-shear viscosity and increase the heterogeneity of the recycled laminates, reducing toughness and increasing haziness. By assessing the morphology and the physicochemical characteristics of the PUR adhesives, it is possible to estimate the impact of these materials on the recyclability of MMPE laminates. PURs presenting a higher degree of mixing between hard and soft phases, as indicated by a lower content of hydrogen-bonded groups among hard segments, are preferred for improving the recyclability of MM-PE laminates.

层压塑料薄膜，特别是单材料多层聚乙烯基（MM-PE）薄膜，在过去十年中引起了包装行业的强烈兴趣。为了闭合材料循环，MM-PE薄膜应该在薄膜到薄膜的机械回收过程中回收，同时保持其预期的性能。然而，MM-PE层压板通常在PE膜层之间含有聚氨酯（PUR）粘合剂，这会影响其可回收性。本文研究了三种含有不同PUR胶粘剂的MM-PE薄膜，以评估PUR特性对薄膜可回收性的影响。对吹膜挤压法制备的MM-PE层合膜的可加工性进行了评价，并对回收膜进行了结构、流变学、力学和光学表征。PUR胶粘剂的组成实质上影响薄膜的闭环可回收性，甚至很小的PUR含量（2wt %）也会阻碍回收过程。总体而言，PUR胶粘剂降低了零剪切粘度，增加了回收层压板的非均质性，降低了韧性，增加了模糊性。通过评估PUR胶粘剂的形态和物理化学特性，可以估计这些材料对MMPE层压板可回收性的影响。提高MM-PE层压板的可回收性，首选软硬相混合程度较高的pur，即硬段间氢键基团含量较低。

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引用次数: 0

V-doped CeO2-loaded biopolymer scaffold for reactive oxygen species scavenging and osteogenic enhancement v掺杂ceo2负载生物聚合物支架的活性氧清除和成骨增强

IF 6 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Polymer Testing

Pub Date : 2025-10-13 DOI: 10.1016/j.polymertesting.2025.109012

Linfeng Fan , Feng Yang , Mengling Jiang , Qiuhui Li , Xinna Bai , Pei Feng , Hao Pan

Excessive reactive oxygen species (ROS) generated during bone scaffold implantation disrupt cellular redox homeostasis and adversely affect stem cell proliferation and osteogenic differentiation, thereby impeding bone regeneration. In this study, vanadium (V) was doped into the cerium oxide (CeO₂) lattice via a wet chemical synthesis, and the resulting V-doped CeO₂ (V-CeO₂) nanoparticles were incorporated into a poly(L-lactic acid) (PLLA) matrix to fabricate composite scaffolds using selective laser sintering. The incorporation of V induced lattice distortion and increased the concentration of oxygen vacancies, which enhanced ROS adsorption and catalytic conversion. X-ray photoelectron spectroscopy (XPS) revealed that V doping increased the Ce(Ⅲ) content from 31.2 % to 39.9 %, thereby facilitating the Ce(Ⅲ)/Ce(IV) redox cycle. Specifically, Ce(Ⅲ)exhibited superoxide dismutase (SOD)-like activity to eliminate O₂^•-, while Ce(IV) showed catalase (CAT)-mimetic activity for H₂O₂ decomposition. In vitro evaluations demonstrated that the PLLA/V-CeO₂ scaffold significantly reduced intracellular ROS levels and upregulated osteogenic gene expression, including BMP-2 and RUNX2. Moreover, the scaffolds exhibited favorable biocompatibility, supporting osteoblast adhesion, proliferation, and differentiation. These results suggest that V-CeO₂-integrated scaffolds hold promise for ROS-regulated bone tissue repair.

骨支架植入过程中产生的过多活性氧（ROS）破坏细胞氧化还原稳态，对干细胞增殖和成骨分化产生不利影响，从而阻碍骨再生。在本研究中，通过湿法化学合成将钒(V)掺杂到氧化铈（CeO2）晶格中，并将得到的V掺杂的CeO2 （V-CeO2）纳米颗粒掺入聚l -乳酸（PLLA）基体中，采用选择性激光烧结制备复合支架。V的掺入引起了晶格畸变，增加了氧空位的浓度，增强了活性氧的吸附和催化转化。x射线光电子能谱（XPS）显示，V掺杂使Ce（Ⅲ）含量由31.2%提高到39.9%，促进了Ce（Ⅲ）/Ce（IV）的氧化还原循环。具体来说，Ce（Ⅲ）表现出类似超氧化物歧化酶（SOD）的活性来消除O2•-，而Ce（IV）表现出类似过氧化氢酶（CAT）的活性来分解H2O2。体外评估表明，PLLA/V-CeO2支架显著降低细胞内ROS水平，上调BMP-2和RUNX2等成骨基因表达。此外，支架具有良好的生物相容性，支持成骨细胞粘附、增殖和分化。这些结果表明，v - ceo2集成支架有望用于ros调控的骨组织修复。

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引用次数: 0

Chain-length dependence of PDMS’ solubility parameter and its correlation with surface tension, density, and viscosity PDMS溶解度参数的链长依赖性及其与表面张力、密度和粘度的相关性

IF 6 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Polymer Testing

Pub Date : 2025-10-13 DOI: 10.1016/j.polymertesting.2025.109011

David G.T. Boucher , Shokoofeh Ghasemi , Andrew B. Croll , Dean C. Webster

This work aims to clarify the understanding of polydimethylsiloxane fluids' (PDMS) solubility by reporting experimental measurements of the chain length dependence of the solubility parameter (

δ

), and the correlation of

δ

with density (ρ), surface tension (

γ

), and viscosity (η). Indeed, the few measurements of

δ

that are found in the literature for PDMS are often conflicting despite this information being critical for designing modern siloxane-based materials and coatings.

γ

,

δ

, and ρ were shown to display a chain length dependence which varies for molecular weights but reaches an asymptote at high molecular weights. This experimental chain length dependence of

δ

, and ρ, was appropriately fitted using a recent model originally presented for

γ

, and linear relationships between

γ

,

δ

, and ρ were highlighted, which could be exploited to estimate

δ

of PDMS from knowledge of

γ

or ρ. Additionally, an alternative method to determine

δ

from variations of ρ (not restricted to PDMS) was exposed by modifying Fedors’ relationship. Finally, the crossover from short chain behavior to long chain behavior was found to coincide with the entanglement molecular weight, but we point out that the cause of the crossover is not the entanglements themselves.

本工作旨在通过报道溶解度参数（δ）的链长依赖性的实验测量，以及δ与密度（ρ），表面张力（γ）和粘度（η）的相关性，阐明对聚二甲基硅氧烷流体（PDMS）溶解度的理解。事实上，尽管这些信息对于设计现代硅氧烷基材料和涂层至关重要，但在文献中发现的关于PDMS的少量δ测量结果经常相互冲突。γ、δ和ρ显示出链长依赖关系，其随分子量的变化而变化，但在高分子量时达到渐近线。δ和ρ的实验链长依赖性使用最初为γ提出的最新模型进行了适当的拟合，并强调了γ， δ和ρ之间的线性关系，可以利用γ或ρ的知识来估计PDMS的δ。此外，通过修改Fedors关系，揭示了从ρ的变化（不限于PDMS）中确定δ的替代方法。最后，发现从短链行为到长链行为的交叉与纠缠分子量一致，但我们指出交叉的原因不是纠缠本身。

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引用次数: 0

High cycle fatigue and wear behavior of ta-C and a-C:H coated PEEK polymer spur gears under dry contact conditions 干接触条件下ta-C和a-C:H涂层PEEK聚合物直齿齿轮的高周疲劳和磨损行为

IF 6 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Polymer Testing

Pub Date : 2025-10-12 DOI: 10.1016/j.polymertesting.2025.109009

Bor Mojškerc , Tanja Stiller , Aleš Durjava , Nikola Vukašinović

Diamond-like carbon (DLC) coatings are under investigation as a potential solution for extending the service life of polymer gears. This study examines the fatigue and wear behavior of polyetheretherketone (PEEK) polymer gears coated with tetrahedral amorphous carbon (ta-C) and hydrogenated amorphous carbon (a-C:H) at thicknesses of 2 μm and 5 μm. The gears were subjected to reference gear pair testing at 1.8 Nm torque under dry contact conditions in a climate-controlled environment.

The PEEK substrate and the DLC coated gear failure mechanisms include both tooth flank and root fatigue fractures, with minor tooth surface wear observed. Although DLC coatings wore off relatively early when meshing with steel gears, the service life of the ta-C (5 μm) and a-C:H (5 μm) coated gears was approximately twice that of the PEEK substrate gears and ta-C (2 μm) coated gears. In addition, the a-C:H coatings caused minimal wear on the steel counterparts due to their higher sp² hybridized graphite structure, whereas the ta-C coatings caused major wear due to their predominantly sp³ hybridized diamond structure. Overall, the results demonstrate that ta-C (5 μm) and a-C:H (5 μm) coatings significantly improve the durability and performance of PEEK polymer gears, highlighting their potential for demanding applications.

类金刚石（DLC）涂层作为延长聚合物齿轮使用寿命的潜在解决方案正在研究中。本研究考察了厚度为2 μm和5 μm的四面体非晶碳（ta-C）和氢化非晶碳（a-C:H）涂层的聚醚醚酮（PEEK）聚合物齿轮的疲劳和磨损行为。在气候控制的干接触条件下，齿轮在1.8 Nm扭矩下进行参考齿轮对测试。PEEK基板和DLC涂层齿轮的失效机制包括齿侧和齿根疲劳断裂，齿面磨损较小。尽管DLC涂层在与钢齿轮啮合时磨损相对较早，但ta-C （5 μm）和a-C:H （5 μm）涂层齿轮的使用寿命大约是PEEK基板齿轮和ta-C （2 μm）涂层齿轮的两倍。此外，由于a-C:H涂层具有较高的sp2杂化石墨结构，因此对钢涂层造成的磨损最小，而ta-C涂层主要是由于其sp3杂化金刚石结构造成的磨损。总体而言，结果表明，ta-C （5 μm）和a-C:H （5 μm）涂层显著提高了PEEK聚合物齿轮的耐久性和性能，突出了它们在苛刻应用中的潜力。

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引用次数: 0

Effects of NaOH/NaCl pretreatment on water absorption behavior of rape straw powder/PVC composites NaOH/NaCl预处理对油菜秸秆粉/PVC复合材料吸水性能的影响

IF 6 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Polymer Testing

Pub Date : 2025-10-12 DOI: 10.1016/j.polymertesting.2025.109004

Zhongqing Yang, Keping Zhang, Junqian Yang, Yang Zhang, Yanan Zhang, Xi Zhang, Hanqing Zhang

The rape straw treated with different concentrations of NaOH and NaCl were used as fillers, and rape straw powder/PVC composites were prepared by extrusion method. The water absorption behavior, degradation of mechanical properties, and wear resistance of the composites were studied. The results showed that the saturated water absorption rate of the composites treated with 7 % NaOH was the highest, and the mechanical properties and wear resistance were seriously degraded, the composites treated with 7 % NaCl showed excellent water resistance and property stability. The hydrophilic component in the fibers was removed by NaCl treatment, the diffusion rate of water was effectively suppressed. The structure of the fibers was excessively destroyed by high concentration NaOH, providing channels for water molecules. The numerical simulation revealed that water molecules diffused along the directions of width and thickness of the composites in a step-like manner, gradually penetrating into the surface and interior of the composites, finally reaching the three-dimensional diffusion equilibrium state. NaCl treatment significantly enhanced the water resistance of composites compared with NaOH treatment, which provided an important theoretical basis for improving the durability of WPCs in water environment.

以不同浓度NaOH和NaCl处理过的油菜秸秆为填料，采用挤压法制备了油菜秸秆粉/PVC复合材料。研究了复合材料的吸水性能、力学性能和耐磨性。结果表明：7% NaOH处理的复合材料饱和吸水率最高，力学性能和耐磨性严重下降；7% NaCl处理的复合材料具有优异的耐水性和性能稳定性。NaCl处理可去除纤维中的亲水成分，有效抑制水的扩散速率。高浓度NaOH破坏了纤维的结构，为水分子提供了通道。数值模拟表明，水分子沿复合材料的宽度和厚度方向呈阶梯状扩散，逐渐渗透到复合材料的表面和内部，最终达到三维扩散平衡状态。与NaOH处理相比，NaCl处理显著提高了复合材料的耐水性，为提高复合材料在水环境中的耐久性提供了重要的理论依据。

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引用次数: 0

Improving the thermo-oxidative stability of low-density polyethylene composites reinforced with Luffa cylindrica fibers 提高丝瓜纤维增强低密度聚乙烯复合材料的热氧化稳定性

IF 6 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Polymer Testing

Pub Date : 2025-10-10 DOI: 10.1016/j.polymertesting.2025.109002

Abbes Ouaar , Hamida Boussehel , Mohammad Jawaid , Ramzi Khiari , Hassan Fouad

Natural fibres are promising reinforcements for polymer composites due to their affordability, eco-friendliness, and favorable mechanical properties. This study investigates the enhancement of thermo-oxidative stability in low-density polyethylene (LDPE) composites by incorporating 10 wt% Luffa cylindrica fibres, both untreated and chemically modified via alkaline and acetylation treatments. Fourier-transform infrared spectroscopy (FTIR) revealed that alkali treatment increased the lateral order index (LOI) by 188.3 %, cellulose ratio (CR) by 60 %, and the total crystallinity index (TCI) by 9.2 %, indicating improved structural order. Thermogravimetric analysis (TGA) showed higher initial degradation temperatures for ALF (241 °C) and CLF (262 °C) composites compared to untreated fibres (201 °C). After 120 h thermo-oxidative aging at 100 °C, weight loss was lowest for LDPE/ALF (0.65 ± 0.14 %) and highest for LDPE/CLF (0.79 ± 0.2 %). Mechanical tests demonstrated that CLF composites exhibited the highest tensile strength (8.98 ± 0.58 MPa) and elongation at break (13.6 ± 2.3 %). These results confirm that fibre treatments enhance interfacial adhesion, crystallinity, and thermal resistance, making treated luffa fibre/LDPE composites suitable for packaging, automotive, and construction applications requiring improved durability.

天然纤维因其可负担性、环保性和良好的机械性能而成为聚合物复合材料的增强材料。本研究研究了低密度聚乙烯（LDPE）复合材料热氧化稳定性的增强，通过加入10%的丝瓜纤维，未经处理和通过碱性和乙酰化处理进行化学改性。傅里叶红外光谱（FTIR）分析表明，碱处理后的纤维素横向有序指数（LOI）提高了188.3%，纤维素比（CR）提高了60%，总结晶度指数（TCI）提高了9.2%，表明结构有序得到改善。热重分析（TGA）表明，与未经处理的纤维（201°C）相比，ALF（241°C）和CLF（262°C）复合材料的初始降解温度更高。在100℃热氧化老化120 h后，LDPE/ALF的失重最小（0.65±0.14%），LDPE/CLF的失重最大（0.79±0.2%）。力学试验表明，CLF复合材料具有最高的抗拉强度（8.98±0.58 MPa）和断裂伸长率（13.6±2.3%）。这些结果证实，纤维处理增强了界面附着力、结晶度和耐热性，使处理过的丝瓜纤维/LDPE复合材料适用于需要提高耐久性的包装、汽车和建筑应用。

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引用次数: 0

Structure and properties of a multilayer composite material for cryogenic applications: From laboratory to industrial scale 低温应用多层复合材料的结构和性能：从实验室到工业规模

IF 6 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Polymer Testing

Pub Date : 2025-10-04 DOI: 10.1016/j.polymertesting.2025.108999

Anna Krzak , Agnieszka J. Nowak , Jiri Frolec , Tomas Kralik , Dariusz Boroński , Maciej Kotyk , Magdalena Bogacka , Grzegorz Matula

Glass-epoxy composites are a type of structural material widely used in the aerospace, automotive, wind energetics and construction industries. This study provides a thorough analysis of the mechanical, thermal and electrical properties of a glass-epoxy composite produced under industrial conditions, based on testing at room and cryogenic temperatures. The industrial-scale composite exhibited significantly lower thermal conductivity than the laboratory-prepared sample across the entire temperature range. We attribute this difference to qualitative or quantitative changes in the glass reinforcement. Cyclic loading tests showed only minor degradation of Young's modulus, with values increasing to ∼30–31 GPa under cryogenic conditions. The composite exhibited significant improvements in tensile strength (638 MPa, +54 %), flexural strength (1030 MPa, +87 %), and nearly doubled fracture toughness (42.2 MPa√m), while maintaining comparable impact resistance. These results highlight the excellent mechanical performance and reliability of the material at −196 °C, confirming its suitability for cryogenic applications. This study also evaluates the environmental impact of different composite material manufacturing processes via life cycle assessment (LCA) analysis. The findings suggest that, while the hydraulic press method offers excellent mechanical performance, it has the greatest environmental impact due to its high energy consumption, significant waste generation and contribution to climate change. These results contribute to the development of sustainable composite technologies and may serve as a foundation for further research or for comparing different materials to determine the most suitable option.

玻璃环氧复合材料是一种广泛应用于航空航天、汽车、风能和建筑行业的结构材料。本研究在室温和低温测试的基础上，对工业条件下生产的玻璃环氧复合材料的机械、热学和电学性能进行了全面分析。在整个温度范围内，工业规模的复合材料的导热性明显低于实验室制备的样品。我们将这种差异归因于玻璃增强的定性或定量变化。循环加载试验表明，杨氏模量只有轻微的退化，在低温条件下，杨氏模量增加到~ 30-31 GPa。复合材料在抗拉强度（638 MPa, + 54%）、抗折强度（1030 MPa, + 87%）和断裂韧性（42.2 MPa / m）方面均有显著提高，同时保持了相当的抗冲击性。这些结果突出了该材料在- 196°C下的优异机械性能和可靠性，证实了其适用于低温应用。本研究亦透过生命周期评估（LCA）分析，评估不同复合材料制造工艺对环境的影响。研究结果表明，尽管液压机方法具有优异的机械性能，但由于其高能耗、大量废物产生和对气候变化的贡献，它对环境的影响最大。这些结果有助于可持续复合材料技术的发展，并可作为进一步研究或比较不同材料以确定最合适选择的基础。

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引用次数: 0

From ultralight microcellular to nanocellular poly (lactic acid) foams through tailoring transcrystalline structures of in-situ nanofibrillar composites 通过裁剪原位纳米纤维复合材料的跨晶结构，从超轻微细胞到纳米细胞聚乳酸泡沫

IF 6 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Polymer Testing

Pub Date : 2025-10-03 DOI: 10.1016/j.polymertesting.2025.109001

Mahboobeh Shahnooshi , Volker Altstädt , Christian Brütting , Petra Pötschke , Azizeh Javadi , Jens Telgkamp

The foaming properties of poly (lactic acid) (PLA) were enhanced by improving its crystallization behavior and melt elasticity through the incorporation of in-situ fibrillated poly (butylene terephthalate) (PBT). Shear rheological studies of the fabricated isotropic in-situ nanofibrillar composites (NFCs) revealed that the PBT nanofibrils (NFs) established a rheological percolated network at contents below 1 wt%. Elongational rheology further confirmed that the formed network significantly increased the strain-hardening factor and, consequently, improved foamability. Batch foaming was conducted using supercritical CO₂ (scCO₂) as a physical blowing agent under various temperature–pressure conditions. The crystalline phase morphology was tailored by both the foaming conditions and the PBT NF content, which, in turn, influenced the foam morphology and density. Foam characteristics were analyzed based on high-pressure differential scanning calorimetry (HP-DSC) results and morphological observations of the foam's crystalline phase. The orthogonal patterning of crystallized PLA nanodomains on the surface of PBT NFs led to the formation of two-dimensional nanohybrid shish-kebab (NHSK) superstructures. The incorporation of these fine, flexible NHSK structures within the foam cell walls resulted in ultra-lightweight foams with closed-cell microcellular morphology, a foam density of 47 kg/m³, and a cell density of 1.5 × 10⁹ cells/cm³. At lower saturation temperatures, a thicker but still flexible NHSK network formed a beehive-like framework during expansion, with each compartment containing interconnected nanocellular foam structures. At higher PBT NF contents, the development of a rigid, fan-shaped transcrystalline PLA phase around PBT NF bundles restricted the expansion of highly nucleated samples, yielding a closed-cell nanocellular morphology. Despite the high crystallinity of these nanocellular foams, relative foam densities below 0.5 were achieved, attributed to their exceptionally high cell densities.

通过加入原位纤化聚对苯二甲酸丁二酯（PBT）改善聚乳酸（PLA）的结晶行为和熔体弹性，提高了PLA的发泡性能。对制备的各向同性原位纳米纤维复合材料（nfc）的剪切流变学研究表明，PBT纳米纤维（NFs）在含量低于1wt %时建立了流变渗透网络。拉伸流变学进一步证实，形成的网络显著提高了应变硬化系数，从而改善了泡沫性。以超临界CO2 （scCO2）为物理发泡剂，在不同温度压力条件下进行间歇发泡。发泡条件和PBT NF含量决定了泡沫的结晶相形态，而PBT NF含量又影响泡沫的形态和密度。根据高压差示扫描量热法（HP-DSC）结果和泡沫结晶相的形态观察分析泡沫特征。在PBT - NFs表面正交图案化PLA纳米畴，形成了二维纳米杂化羊肉串（NHSK）超结构。在泡沫细胞壁中加入这些精细、灵活的NHSK结构，形成了具有闭孔微细胞形态的超轻泡沫，泡沫密度为47 kg/m3，细胞密度为1.5 × 109个细胞/cm3。在较低的饱和温度下，较厚但仍具有弹性的NHSK网络在膨胀过程中形成蜂箱状的框架，每个隔室包含相互连接的纳米细胞泡沫结构。当PBT NF含量较高时，PBT NF束周围刚性的扇形跨晶PLA相的发展限制了高核样品的膨胀，产生封闭细胞的纳米细胞形态。尽管这些纳米细胞泡沫的结晶度很高，但由于其异常高的细胞密度，相对泡沫密度低于0.5。

{"title":"From ultralight microcellular to nanocellular poly (lactic acid) foams through tailoring transcrystalline structures of in-situ nanofibrillar composites","authors":"Mahboobeh Shahnooshi , Volker Altstädt , Christian Brütting , Petra Pötschke , Azizeh Javadi , Jens Telgkamp","doi":"10.1016/j.polymertesting.2025.109001","DOIUrl":"10.1016/j.polymertesting.2025.109001","url":null,"abstract":"<div><div>The foaming properties of poly (lactic acid) (PLA) were enhanced by improving its crystallization behavior and melt elasticity through the incorporation of in-situ fibrillated poly (butylene terephthalate) (PBT). Shear rheological studies of the fabricated isotropic in-situ nanofibrillar composites (NFCs) revealed that the PBT nanofibrils (NFs) established a rheological percolated network at contents below 1 wt%. Elongational rheology further confirmed that the formed network significantly increased the strain-hardening factor and, consequently, improved foamability. Batch foaming was conducted using supercritical CO<sub>2</sub> (scCO<sub>2</sub>) as a physical blowing agent under various temperature–pressure conditions. The crystalline phase morphology was tailored by both the foaming conditions and the PBT NF content, which, in turn, influenced the foam morphology and density. Foam characteristics were analyzed based on high-pressure differential scanning calorimetry (HP-DSC) results and morphological observations of the foam's crystalline phase. The orthogonal patterning of crystallized PLA nanodomains on the surface of PBT NFs led to the formation of two-dimensional nanohybrid shish-kebab (NHSK) superstructures. The incorporation of these fine, flexible NHSK structures within the foam cell walls resulted in ultra-lightweight foams with closed-cell microcellular morphology, a foam density of 47 kg/m<sup>3</sup>, and a cell density of 1.5 × 10<sup>9</sup> cells/cm<sup>3</sup>. At lower saturation temperatures, a thicker but still flexible NHSK network formed a beehive-like framework during expansion, with each compartment containing interconnected nanocellular foam structures. At higher PBT NF contents, the development of a rigid, fan-shaped transcrystalline PLA phase around PBT NF bundles restricted the expansion of highly nucleated samples, yielding a closed-cell nanocellular morphology. Despite the high crystallinity of these nanocellular foams, relative foam densities below 0.5 were achieved, attributed to their exceptionally high cell densities.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"152 ","pages":"Article 109001"},"PeriodicalIF":6.0,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Enhanced heat conductivity ingraphene/polyethylene nanocomposites through two-stage graphene dispersion using hyperbranched polyethylene 利用超支化聚乙烯两阶段分散石墨烯，增强石墨烯/聚乙烯纳米复合材料的导热性

IF 6 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Polymer Testing

Pub Date : 2025-10-02 DOI: 10.1016/j.polymertesting.2025.109000

Mahdi Shafiee , Farhad Sharif , Saeedeh Mazinani , Zahra Balzade

Enhancing the thermal conductivity of polyethylene (PE) is critical for improving processing efficiency and reducing energy consumption. This study introduces a novel two-stage process to disperse graphene in PE using hyperbranched polyethylene (HBPE). A graphene-HBPE (G-HBPE) masterbatch was prepared via solution mixing and sonication of graphite in chloroform with HBPE, followed by solvent removal and melt mixing with low-density PE (LDPE). Incorporating less than 1 wt% graphene nanoplatelets (GNPs) increased thermal conductivity by 50 %, from 0.312 to 0.468 W/m·K, while preserving processability (melt flow index: 0.85 to 0.816 g/10 min) and modestly enhancing mechanical properties (modulus: 95.8–165.2 MPa). Field emission scanning electron microscopy revealed uniform graphene dispersion and strong interfacial bonding, attributed to HBPE's CH-π interactions and steric stabilization. This approach outperforms prior methods, offering a scalable strategy for PE-based thermal management materials in electronics and other applications.

提高聚乙烯（PE）的导热性是提高加工效率和降低能耗的关键。本研究介绍了一种利用超支化聚乙烯（HBPE）在聚乙烯中分散石墨烯的新型两阶段工艺。将石墨与HBPE在氯仿中进行溶液混合和超声处理，然后与低密度PE （LDPE）进行溶剂去除和熔体混合，制备出石墨烯-HBPE （G-HBPE）母粒。加入不到1 wt%的石墨烯纳米片（GNPs）使导热系数提高了50%，从0.312到0.468 W/m·K，同时保持了可加工性（熔体流动指数：0.85到0.816 g/10 min），并适度提高了机械性能（模量：95.8-165.2 MPa）。场发射扫描电子显微镜显示，由于HBPE的CH-π相互作用和空间稳定，石墨烯分散均匀，界面键合强。该方法优于先前的方法，为电子和其他应用中的pe基热管理材料提供了可扩展的策略。

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引用次数: 0