Iranian Polymer Journal最新文献_第9页

Enhanced electromechanical actuation in acrylic elastomer foam using barium titanate and Ketjenblack dispersed interpenetrated polymer network 利用钛酸钡和 Ketjenblack 分散互穿聚合物网络增强丙烯酸弹性体泡沫中的机电致动功能

IF 2.4 3区化学 Q3 POLYMER SCIENCE

Iranian Polymer Journal

Pub Date : 2024-04-05 DOI: 10.1007/s13726-024-01308-7

Dhananjay Sahu, Raj Kumar Sahu

VHB 4910/05 polymeric foam tape manufactured by 3M conglomerate is widely acknowledged as a dielectric elastomer with exceptional electromechanical actuation performance than its counterparts. However, actuation in VHB elastomers is well-known to be enhanced by cross-linkers and plasticizers, the impacts of particulate fillers on their structure, properties, and performance are yet to be recognized. This work addresses the influences of barium titanate (BT) and Ketjenblack (KB) dispersed trimethylolpropane trimethacrylate (TMPTMA) as fillers on the behavior of VHB 4910 elastomer for the planar actuators. The elastomer composites are prepared by swelling and then thermochemical curing of the samples in BT and KB dispersed TMPTMA. The incorporation of fillers in the elastomer matrix is confirmed by comparing optical micrographs, swelling degree, cross-link density, molecular bonds, optical bandgap, and opto-dielectric characteristics. Thus, the dielectric and mechanical behavior and electromechanical actuation performance of the filler-reinforced elastomer are discussed. Improved dielectric constant and specifically reduced elastic modulus are witnessed due to the gelation of TMPTMA leading to a new range of actuation in VHB 4910 elastomer. The areal actuation in elastomer comprising BT, KB and BT-KB particle dispersed TMPTMA is estimated at about 180%, 150% and 165%, respectively. The low electric field requirement is noticed for BT-containing elastomer composite. This work scopes the use of swelling techniques to modify microporous elastomers with particulate fillers towards soft actuators, sensors, and energy generators.

Graphical abstract

摘要 3M 集团生产的 VHB 4910/05 聚合泡沫胶带被公认为是一种介电弹性体，与同类产品相比具有优异的机电驱动性能。然而，众所周知，交联剂和增塑剂可增强 VHB 弹性体的致动性能，但颗粒填料对其结构、性能和表现的影响仍有待认识。本研究探讨了钛酸钡（BT）和 Ketjenblack（KB）分散填料三羟甲基丙烷三甲基丙烯酸酯（TMPTMA）对平面致动器用 VHB 4910 弹性体行为的影响。弹性体复合材料是通过在 BT 和 KB 分散的 TMPTMA 中对样品进行溶胀和热化学固化制备而成的。通过比较光学显微照片、溶胀度、交联密度、分子键、光带隙和光电特性，证实了填料在弹性体基体中的加入。因此，本文讨论了填料增强弹性体的介电和机械行为以及机电致动性能。TMPTMA 的凝胶化改善了介电常数，特别是降低了弹性模量，从而为 VHB 4910 弹性体带来了新的致动范围。据估计，由 BT、KB 和 BT-KB 粒子分散的 TMPTMA 所组成的弹性体的面积致动率分别约为 180%、150% 和 165%。含有 BT 的弹性体复合材料对电场的要求较低。这项工作旨在利用膨胀技术改造含有微粒填料的微孔弹性体，使其成为软致动器、传感器和能量发生器。图表摘要

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引用次数: 0

Reactive extrusion foaming of poly(lactic acid): tailoring foam properties through controlling in-process chemical reactions 聚乳酸的反应性挤压发泡：通过控制加工过程中的化学反应定制泡沫特性

IF 2.4 3区化学 Q3 POLYMER SCIENCE

Iranian Polymer Journal

Pub Date : 2024-04-01 DOI: 10.1007/s13726-024-01304-x

Maryam Valipour, Mahdi Rahmanifard, Navid Jaberi, Alireza Shadman, Mehdi Hatami, Hossein Ali Khonakdar, Farkhondeh Hemmati

A continuous extrusion foaming process was performed on poly(lactic acid) (PLA) in the presence of different chemical foaming agents (CFAs) and a chain extender additive using different extruder barrel and die temperature profiles. Chemical reactions, which are involved in the extrusion foaming process of PLA, are intensely investigated to control the reactive extrusion process and tailor the foam final properties. A set of experiments was designed using the response surface methodology to evaluate the effects of material and processing parameters and optimize the PLA foam property. The results showed that the maximum void fraction, i.e. 0.55, was obtained by exothermic CFA at higher extruder temperatures. In contrast to the exothermic CFA, the addition of endothermic CFAs did not result in lightweight biodegradable foams. The void fractions of these extruded foams were less than 0.05. The presence of water molecules as a by-product of the decomposition reaction and also relatively lower decomposition temperatures of the endothermic CFAs have been considered as the main reasons. Among the variables studied, the CFA type had the strongest impact on the foam properties. In the second step, the barrel and die temperatures were adjusted accordingly.

Graphical abstract

摘要采用不同的挤压机机筒和模头温度曲线，在不同化学发泡剂（CFA）和扩链添加剂的存在下，对聚（乳酸）（PLA）进行了连续挤压发泡工艺。对聚乳酸挤压发泡过程中涉及的化学反应进行了深入研究，以控制反应性挤压过程并调整泡沫的最终特性。采用响应面方法设计了一组实验，以评估材料和加工参数的影响，优化聚乳酸泡沫的性能。结果表明，在较高的挤出机温度下，放热 CFA 可获得最大空隙率，即 0.55。与放热型 CFA 相反，添加内热型 CFA 不会产生轻质可生物降解泡沫。这些挤出泡沫的空隙率小于 0.05。主要原因是分解反应的副产品水分子的存在，以及内热型 CFA 的分解温度相对较低。在所研究的变量中，CFA 类型对泡沫特性的影响最大。在第二步中，对料筒和模具温度进行了相应调整。图表摘要

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引用次数: 0

Mechanical and thermal investigation of high-density polyethylene/multi-walled carbon nanotube/tungsten disulfide hybrid composites 高密度聚乙烯/多壁碳纳米管/二硫化钨混合复合材料的力学和热学研究

IF 2.4 3区化学 Q3 POLYMER SCIENCE

Iranian Polymer Journal

Pub Date : 2024-04-01 DOI: 10.1007/s13726-024-01305-w

Sampath Kumar Sudarsanam, K. Panneerselvam

This study investigates the impact of addition of different weight percentages of tungsten disulphide (WS₂) lubricant on the thermal and mechanical properties of high density polyethylene (HDPE) hybrid composites reinforced with a multi-walled carbon nanotube (MWCNT). HDPE composites were fabricated using a twin-screw extruder process employed to add reinforcement and lubricants in different weight percentages (%, by weight). X-ray diffraction (XRD) patterns indicated the distribution and dispersion of filler materials in the HDPE matrix. The quality of the composite was investigated by measuring the mechanical properties such as impact strength, hardness, tensile strength, and flexural strength. Thermogravimetric analysis (TGA) was employed to examine the thermal stability of the composite material. Main decomposition temperatures were determined using derivative thermogravimetry (DTG) analysis. Thermal transitions and degree of crystallisation (X_c) of the polymeric materials used were investigated by using differential scanning calorimetry (DSC) technique. The lubricant was added in three varying amounts of 2%, 4% and 8% (by weight) whilst MWCNT was maintained at 1% (by weight). The experimental results revealed that the composite with 2% (by weight) of WS₂ provides better mechanical properties such as impact strength, flexural strength, tensile strength, and hardness. With an increase in lubricant percentage, agglomeration of particles is found to be dominant in the composite, and the composite with 4% (by weight) of WS₂ displays better thermal properties, as determined using TGA, DTG and DSC analytical techniques.

Graphical abstract

本研究探讨了添加不同重量百分比的二硫化钨（WS2）润滑剂对以多壁碳纳米管（MWCNT）增强的高密度聚乙烯（HDPE）混合复合材料的热性能和机械性能的影响。高密度聚乙烯（HDPE）复合材料是采用双螺杆挤出机工艺制成的，其中添加了不同重量百分比（%，按重量计）的增强剂和润滑剂。X 射线衍射（XRD）图显示了填充材料在高密度聚乙烯基体中的分布和分散情况。通过测量冲击强度、硬度、拉伸强度和弯曲强度等机械性能，对复合材料的质量进行了研究。热重分析（TGA）被用来检测复合材料的热稳定性。使用导数热重分析法（DTG）确定了主要分解温度。使用差示扫描量热仪 (DSC) 技术研究了所用聚合物材料的热蜕变和结晶度 (Xc)。润滑剂的添加量分别为 2%、4% 和 8%（按重量计），而 MWCNT 的添加量保持在 1%（按重量计）。实验结果表明，添加 2%（重量）WS2 的复合材料具有更好的机械性能，如冲击强度、弯曲强度、拉伸强度和硬度。根据 TGA、DTG 和 DSC 分析技术的测定，随着润滑剂比例的增加，复合材料中的颗粒团聚现象占主导地位，WS2 含量为 4%（重量百分比）的复合材料具有更好的热性能。

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引用次数: 0

Enhanced smoke/toxicity suppression of intumescent flame retardant thermoplastic polyurethane composites with the addition of graphene 添加石墨烯增强膨胀阻燃热塑性聚氨酯复合材料的烟雾/毒性抑制能力

IF 2.4 3区化学 Q3 POLYMER SCIENCE

Iranian Polymer Journal

Pub Date : 2024-03-30 DOI: 10.1007/s13726-024-01303-y

Leila Taghi-Akbari, Mohammad Reza Naimi-Jamal, Shervin Ahmadi, Saeed Bakhtiyari

High flame retardancy with significant suppression of toxic smoke and melt-dripping are challenging issues associated with flame-retardant thermoplastic polyurethane (TPU). To address these issues, in this work, graphene (Gr) was used as an effective two-dimensional smoke-toxicity suppressant with loadings less than 1 wt%, in combination with two efficient intumescent flame retardant (IFR) systems reported in our previous works. The IFRs were consisted of ammonium polyphosphate, pentaerythritol (PER), and melamine polyphosphate (MPP) with MPP:PER ratios of 10:1 (IFR1) and 1:1 (IFR2). Cone calorimeter test (CCT) results showed outstanding flame retardancy and excellent toxic smoke suppression in TPU/IFR1/0.75%Gr sample with reduced peak heat release rate (PHRR) by 85.3%, peak smoke production rate (PSPR) by 92.1%, and peak carbon monoxide production (PCOP) by 91.3% compared with neat TPU. TPU/IFR2/0.5%Gr sample exhibited a similar trend, with the PHRR, PSPR, and PCOP reduced by 66.8%, 62.5%, and 64.0%, respectively, with good anti-dripping property. The barrier function of graphene had a significant influence on reducing total smoke released in TPU/IFR1/0.75%Gr and TPU/IFR2/0.5%Gr samples by 82.1% and 34.3%, respectively, compared with their related TPU/IFRs composites. TPU nanocomposites reached a UL-94 V-0 rating and LOI of more than 29%. TGA results indicated improved char-forming, and FESEM depicted the graphitized integrated char structures. Mechanical performance of TPU/IFR2/0.5%Gr exhibited an enhanced ductility compared with the neat TPU. The possible flame retardancy mechanism was proposed based on the data obtained from the CCT, TGA, and EDS elemental analysis.

Graphical abstract

阻燃性热塑性聚氨酯（TPU）具有高阻燃性，并能显著抑制有毒烟雾和熔滴，这是阻燃性热塑性聚氨酯（TPU）所面临的挑战性问题。为了解决这些问题，在这项工作中，我们将石墨烯（Gr）作为一种有效的二维烟毒抑制剂（负载量小于 1 wt%），与我们之前工作中报告的两种高效膨胀型阻燃剂（IFR）系统结合使用。IFR 由聚磷酸铵、季戊四醇（PER）和三聚氰胺聚磷酸盐（MPP）组成，MPP 与 PER 的比例分别为 10:1 （IFR1）和 1:1（IFR2）。锥形量热仪测试（CCT）结果表明，与纯热塑性聚氨酯相比，热塑性聚氨酯/IFR1/0.75%Gr 样品具有优异的阻燃性和出色的有毒烟雾抑制能力，其峰值热释放率（PHRR）降低了 85.3%，峰值烟雾产生率（PSPR）降低了 92.1%，峰值一氧化碳产生率（PCOP）降低了 91.3%。热塑性聚氨酯/IFR2/0.5%Gr 样品也表现出类似的趋势，PHRR、PSPR 和 PCOP 分别降低了 66.8%、62.5% 和 64.0%，具有良好的防滴漏性能。与相关的 TPU/IFRs 复合材料相比，石墨烯的阻隔功能对降低 TPU/IFR1/0.75%Gr 和 TPU/IFR2/0.5%Gr 样品的总烟雾释放量有显著影响，分别降低了 82.1% 和 34.3%。TPU 纳米复合材料达到了 UL-94 V-0 级，LOI 超过 29%。TGA 结果表明成炭性得到改善，FESEM 显示了石墨化的集成炭结构。与纯热塑性聚氨酯相比，热塑性聚氨酯/IFR2/0.5%Gr 的机械性能表现出更高的延展性。根据 CCT、TGA 和 EDS 元素分析获得的数据，提出了可能的阻燃机制。

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引用次数: 0

Microwave-assisted aggregation of CO2-switchable polystyrene latexes prepared through emulsion polymerization using cationic stabilizers 使用阳离子稳定剂通过乳液聚合法制备的二氧化碳可切换聚苯乙烯胶乳的微波辅助聚合反应

IF 2.4 3区化学 Q3 POLYMER SCIENCE

Iranian Polymer Journal

Pub Date : 2024-03-30 DOI: 10.1007/s13726-024-01302-z

Sajad Avar, Abbas Rezaee Shirin-Abadi

Microwave irradiation (MWI) is introduced as a novel trigger to aggregate CO₂-switchable latexes. The polystyrene (PS) latexes were synthesized through emulsion polymerization in two ways (using polar monomer 2-dimethylaminoethyl methacrylate (DMAEMA) (as in situ copolymerization), and a well-defined block copolymer, poly(dimethylaminoethyl methacrylate-block-methyl methacrylate), PDMAEMA-b-PMMA as positively charged stabilizing moieties in the presence of 4,4'-(diazene-1,2-diyl) bis(N-(3-(dimethylamino) propyl)-4-methylpentanamide) (DABPA) as an “inistab” (initiator + colloidal stabilizer). Since the polymerization was conducted in acidic media using hydrochloric acid (HCl) to protonate stabilizers, PS latexes could be simply destabilized by adding NaOH. The destabilized latexes were redispersed by introducing CO₂ plus sonication to yield CO₂-switchable latexes. The particle size of the resultant latexes after redispersion was very similar to that of primary latexes, as measured by dynamic light scattering. MWI and conventional heating (CH) stimuli were applied to aggregate the CO₂-switchable PS latex particles. The influence of different factors on the time required for aggregation and particle size changes of the synthesized latexes was studied. These two methods of destabilization of PS latexes produce completely different switching behavior. Findings revealed that microwave-assisted aggregation (MAA) relative to CH required less time, but an increase in particle size of the redispersed particles in comparison to the original latexes was observed. Therefore, MAA can be assumed as a promising trigger for the aggregation of CO₂-responsive latexes. This facile aggregation process, which could reduce time and energy input, might be of high interest and importance in various applications.

Graphical Abstract

微波辐照（MWI）是聚合二氧化碳可切换胶乳的一种新型触发器。聚苯乙烯（PS）胶乳是通过两种方式的乳液聚合合成的（使用极性单体甲基丙烯酸二甲胺基乙酯（DMAEMA）（原位共聚）和明确的嵌段共聚物聚（甲基丙烯酸二甲胺基乙酯-嵌段-甲基丙烯酸甲酯））、PDMAEMA-b-PMMA 作为带正电荷的稳定分子，4,4'-（重氮-1,2-二基）双(N-(3-(二甲基氨基)丙基)-4-甲基戊酰胺 (DABPA))作为 "inistab"（引发剂+胶体稳定剂）。由于聚合反应是在酸性介质中进行的，使用盐酸（HCl）使稳定剂质子化，因此只需加入 NaOH 即可使 PS 胶乳脱稳。通过引入二氧化碳并进行超声处理，可以重新分散失稳的胶乳，从而得到二氧化碳可切换胶乳。通过动态光散射法测定，重新分散后的胶乳粒径与原生胶乳非常相似。采用 MWI 和传统加热（CH）刺激聚合二氧化碳可切换 PS 胶乳颗粒。研究了不同因素对聚合所需时间和合成胶乳粒度变化的影响。这两种破坏聚苯乙烯胶乳稳定性的方法产生了完全不同的开关行为。研究结果表明，相对于 CH，微波辅助聚集（MAA）所需的时间更短，但与原始胶乳相比，重新分散的颗粒粒径增大。因此，可以认为 MAA 是一种很有前景的二氧化碳反应胶乳聚合触发器。这种简便的聚合过程可以减少时间和能量的投入，在各种应用中可能具有很高的兴趣和重要性。

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引用次数: 0

Temperature-dependent storage modulus of polymer nanocomposites, blends and blend-based nanocomposites based on percolation and De Gennes’s self-similar carpet theories 基于渗流和 De Gennes 自相似地毯理论的聚合物纳米复合材料、共混物和基于共混物的纳米复合材料随温度变化的存储模量

IF 2.4 3区化学 Q3 POLYMER SCIENCE

Iranian Polymer Journal

Pub Date : 2024-03-25 DOI: 10.1007/s13726-024-01300-1

Reza Mohammadi, Esmail Sharifzadeh, Neda Azimi

Temperature-dependent storage modulus of polymer nanocomposites, blends and blend-based nanocomposites was studied using both analytical and experimental approaches. The analytical strategy comprised modeling the thermomechanical property of the systems based on parameters affecting the conversion degree of polymer chains in state-to-state transitions and mechanical characteristics of the polymer/polymer interface. Accordingly, percolation theory was developed to define the order of conversion rate and conversion degree of polymer chains considering the thermomechanical characteristics of the neat polymer matrix, behavior of nanoparticles in the system and formation of polymer/particle interphase region. The effect of interphase on a temperature-dependent conversion of polymer molecules was estimated based on De Gennes’s self-similar using the molecular characteristics of the adsorbed polymer chains and related scaling factor. To validate the model predictions, different neat, blend, nanocomposite and blend-based nanocomposite samples were prepared using high-density polyethylene, polyethylene terephthalate and hollow graphene oxide nanoparticles, where needed, and subjected to dynamic mechanical thermal analysis and other required tests. Besides providing acceptably accurate predictions in the case of all neat and nanocomposite samples, the model was proved to be independent of the system’s morphological variation.

Graphical abstract

采用分析和实验方法研究了聚合物纳米复合材料、共混物和基于共混物的纳米复合材料随温度变化的存储模量。分析策略包括根据影响聚合物链在状态-状态转换中的转换度以及聚合物/聚合物界面的机械特性的参数，建立系统的热机械特性模型。因此，考虑到纯聚合物基体的热力学特性、纳米粒子在系统中的行为以及聚合物/粒子相间区的形成，建立了渗流理论来定义聚合物链的转化率和转化度的顺序。利用吸附聚合物链的分子特性和相关比例因子，根据 De Gennes 自相似估算了相间区对随温度变化的聚合物分子转化率的影响。为验证模型预测结果，根据需要使用高密度聚乙烯、聚对苯二甲酸乙二醇酯和空心氧化石墨烯纳米颗粒制备了不同的纯样品、共混样品、纳米复合材料和基于共混的纳米复合材料样品，并进行了动态机械热分析和其他必要的测试。除了对所有纯样品和纳米复合材料样品提供可接受的准确预测外，该模型还被证明不受系统形态变化的影响。

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引用次数: 0

Contribution of graphene oxide obtained from exhausted batteries in polypropylene compositions: mechanical, thermal and rheological properties 从用完的电池中提取的氧化石墨烯在聚丙烯成分中的贡献：机械、热和流变特性

IF 2.4 3区化学 Q3 POLYMER SCIENCE

Iranian Polymer Journal

Pub Date : 2024-03-24 DOI: 10.1007/s13726-024-01301-0

Paola A. Tarachuque, Ana P. Knopik, Reinaldo Y. Morita, Paulo R. S. Bittencourt, Luís A. Pinheiro, Jarem R. Garcia, Alex V. Pedroso, Juliana R. Kloss

Particulate matter and volatile organic compounds pose severe threats to human health. Therefore, in this study samples of polypropylene/graphene oxide with varying compositions were prepared for to be tested in automotive sector. Graphene oxide was obtained through an electrochemical exfoliation of graphite recovered from exhausted batteries. The preparation of the composites was performed using graphene oxide at ratios of 0.3%, 0.7% and 1.0% (w/w), already diluted in a hyperdispersant agent. The composites were compared to both pure polypropylene and polypropylene/carbon black composites. The samples were characterized based on their melt flow index, thermal stability, crystallinity, flammability, and mechanical and rheological properties. The formulations containing graphene oxide obtained from the recycling of exhausted batteries exhibited superior thermal properties and melt flow index compared to pure polypropylene. In addition, the composites containing 0.7% of graphene oxide showed an increase in flow index compared to the composite containing carbon black. The rheological properties of samples containing graphene oxide had values closer to pure polypropylene compared to those containing only hyperdispersant or carbon black. The increase in the flow index of a composite containing graphene oxide can result in energy cost savings during processing. Polypropylene/graphene oxide composites present an interesting alternative by replacing carbon black with recycled graphene oxide, both in terms of costs and environmental impact, aligning with the principles of green chemistry.

Graphical abstract

微粒物质和挥发性有机化合物对人类健康构成严重威胁。因此，本研究制备了不同成分的聚丙烯/氧化石墨烯样品，以便在汽车领域进行测试。氧化石墨烯是通过对从用完的电池中回收的石墨进行电化学剥离而获得的。在制备复合材料时，氧化石墨烯在超分散剂中的稀释比例分别为 0.3%、0.7% 和 1.0%（重量比）。这些复合材料与纯聚丙烯和聚丙烯/炭黑复合材料进行了比较。根据熔体流动指数、热稳定性、结晶度、可燃性以及机械和流变特性对样品进行了表征。与纯聚丙烯相比，从回收的废旧电池中获得的含有氧化石墨烯的配方具有更优越的热性能和熔体流动指数。此外，与含炭黑的复合材料相比，含 0.7% 氧化石墨烯的复合材料的流动指数有所提高。与仅含超分散剂或炭黑的样品相比，含氧化石墨烯样品的流变特性值更接近于纯聚丙烯。含有氧化石墨烯的复合材料流动指数的增加可在加工过程中节约能源成本。聚丙烯/氧化石墨烯复合材料用回收的氧化石墨烯代替炭黑，在成本和环境影响方面都符合绿色化学的原则，是一种有趣的替代品。

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引用次数: 0

Surface modification of membrane bioreactor by hybrid halloysite nanotubes for industrial wastewater treatment containing heavy metals 用混合埃洛石纳米管对膜生物反应器进行表面改性，以处理含重金属的工业废水

IF 2.4 3区化学 Q3 POLYMER SCIENCE

Iranian Polymer Journal

Pub Date : 2024-03-22 DOI: 10.1007/s13726-024-01298-6

Sajjad Gorjizadeh, Masoud Rahbari-Sisakht, Daryoush Emadzadeh

Surface modification of polysulfone (PSF) membrane bioreactor using hybrid halloysite nanotubes (HHNTs) and dendrimers was investigated for industrial wastewater treatment containing heavy metals. Petroleum wastewater was obtained from liquefied gas plant 1200 (NGL 1200) in Gachsaran, Iran. Polysulfone)PSF( membranes were fabricated using hybrid halloysite nanotubes and dendrimers at different concentrations of 0, 0.5, 1, and 2 wt% and identified with certain codes of PSF, HNT0.5, HNT1, and HNT2, respectively. The fabricated membranes were characterized by FTIR, AFM, EDX, SEM, and contact angle analyses. The contact angle decreased as a result of HNT loading in PSF membranes, which was due to the enhancement of the membrane hydrophobicity. The heavy metal rejection in the HNT1 membrane for Cu (II), Pb (II), Ni (II), and Zn (II) was 83.25%, 98.79%, 81.09%, and 85.98%, respectively. Also, the rejection of Ni (II) in PSF was 38.24% which showed a lower amount. Based on the results, the HNT1 membrane which was fabricated using 1 wt% of the hybrid halloysite nanotubes showed the best performance to heavy metals removal from industrial effluents.

Graphical abstract

研究人员利用杂化哈洛石纳米管（HHNTs）和树枝状聚合物对聚砜（PSF）膜生物反应器进行了表面改性，以处理含有重金属的工业废水。石油废水取自伊朗 Gachsaran 的液化气厂 1200（NGL 1200）。使用不同浓度（0、0.5、1 和 2 wt%）的混合埃洛石纳米管和树枝状聚合物制作了聚砜（PSF）膜，并分别用 PSF、HNT0.5、HNT1 和 HNT2 进行了标识。傅立叶变换红外光谱（FTIR）、原子力显微镜（AFM）、乙二胺四乙酸（EDX）、扫描电镜（SEM）和接触角分析对制备的膜进行了表征。在 PSF 膜中添加 HNT 后，接触角减小，这是因为膜的疏水性增强了。HNT1 膜对 Cu (II)、Pb (II)、Ni (II) 和 Zn (II) 重金属的抑制率分别为 83.25%、98.79%、81.09% 和 85.98%。此外，PSF 对镍（II）的剔除率为 38.24%，表明镍（II）的含量较低。根据这些结果，使用 1 wt% 的混合霍洛石纳米管制造的 HNT1 膜在去除工业废水中的重金属方面表现最佳。

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引用次数: 0

Exploring the impact of void content and hygrothermal aging on the performance of carbon/epoxy composite laminates: a comprehensive study 探索空隙含量和湿热老化对碳/环氧复合材料层压板性能的影响：一项综合研究

IF 2.4 3区化学 Q3 POLYMER SCIENCE

Iranian Polymer Journal

Pub Date : 2024-03-20 DOI: 10.1007/s13726-024-01295-9

Abd Baghad, Khalil El Mabrouk

The effect of voids and aging on the moisture absorption behavior, diffusion characteristics, and thermomechanical and mechanical performance of autoclaved laminates has been investigated. However, a series of 12 laminates based on HexPly 8552S/AS4 prepregs were manufactured by varying the autoclave process parameters to create laminates with different void contents and subjected to conditioning and aging processes. The moisture absorption behavior was evaluated, and a Fickian diffusion model was employed to describe the moisture absorption process. The results showed that void content influenced the moisture absorption rate, resulting in faster absorption rate. Hygrothermal aging decreased the glass transition temperature (T_g), indicating a loss of rigidity in the laminates. The decrease in T_g varies between 9.08 and 12.57%, with an average decrease of 10.62 ± 1.25% compared to samples not subjected to aging. Aging also affected the laminate’s compressive modulus, with a reduction ranging from 6.99 to 10.65%. In addition, the laminate’s compressive strength decreased from 12.7 to 19.2%, while interlaminar shear strength experienced a reduction from 16.8 to 25.7%. These results indicate that these properties were negatively impacted after the aging process. On the other hand, the presence of voids does not appear to play a significant role in the observed reductions in mechanical and thermomechanical properties. These findings provide valuable insights into the detrimental effects of voids and aging on the properties of carbon/epoxy composite laminates.

Graphical abstract

空隙和老化对高压灭菌层压板的吸湿行为、扩散特性以及热机械和机械性能的影响已被研究过。然而，通过改变高压灭菌工艺参数，制造出不同空隙含量的层压板，并对其进行调节和老化处理，生产出了一系列基于 HexPly 8552S/AS4 预浸料的 12 种层压板。对吸湿行为进行了评估，并采用菲克扩散模型来描述吸湿过程。结果表明，空隙率影响吸湿率，导致吸湿率加快。湿热老化降低了玻璃化转变温度（Tg），表明层压板失去了刚性。与未老化的样品相比，Tg 下降了 9.08% 至 12.57%，平均下降了 10.62 ± 1.25%。老化还影响了层压模量，降低了 6.99% 到 10.65%。此外，层压强度从 12.7% 下降到 19.2%，层间剪切强度从 16.8% 下降到 25.7%。这些结果表明，这些性能在老化过程后受到了负面影响。另一方面，空隙的存在似乎并没有对观察到的机械和热机械性能的降低起到重要作用。这些发现为了解空隙和老化对碳/环氧复合材料层压板性能的不利影响提供了宝贵的见解。

{"title":"Exploring the impact of void content and hygrothermal aging on the performance of carbon/epoxy composite laminates: a comprehensive study","authors":"Abd Baghad, Khalil El Mabrouk","doi":"10.1007/s13726-024-01295-9","DOIUrl":"10.1007/s13726-024-01295-9","url":null,"abstract":"<div><p>The effect of voids and aging on the moisture absorption behavior, diffusion characteristics, and thermomechanical and mechanical performance of autoclaved laminates has been investigated. However, a series of 12 laminates based on HexPly 8552S/AS4 prepregs were manufactured by varying the autoclave process parameters to create laminates with different void contents and subjected to conditioning and aging processes. The moisture absorption behavior was evaluated, and a Fickian diffusion model was employed to describe the moisture absorption process. The results showed that void content influenced the moisture absorption rate, resulting in faster absorption rate. Hygrothermal aging decreased the glass transition temperature (<i>T</i><sub>g</sub>), indicating a loss of rigidity in the laminates. The decrease in <i>T</i><sub>g</sub> varies between 9.08 and 12.57%, with an average decrease of 10.62 ± 1.25% compared to samples not subjected to aging. Aging also affected the laminate’s compressive modulus, with a reduction ranging from 6.99 to 10.65%. In addition, the laminate’s compressive strength decreased from 12.7 to 19.2%, while interlaminar shear strength experienced a reduction from 16.8 to 25.7%. These results indicate that these properties were negatively impacted after the aging process. On the other hand, the presence of voids does not appear to play a significant role in the observed reductions in mechanical and thermomechanical properties. These findings provide valuable insights into the detrimental effects of voids and aging on the properties of carbon/epoxy composite laminates.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":601,"journal":{"name":"Iranian Polymer Journal","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140202057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A novel chemical route for low-temperature curing of natural rubber using 2,4 dihydroxybenzaldehyde: improved thermal and tensile properties 使用 2,4-二羟基苯甲醛对天然橡胶进行低温硫化的新型化学方法：改善热性能和拉伸性能

IF 2.4 3区化学 Q3 POLYMER SCIENCE

Iranian Polymer Journal

Pub Date : 2024-03-18 DOI: 10.1007/s13726-024-01297-7

Bote Vaishali Raosaheb, Anand Adeppa, Sudhakara Aralihalli, Ekwipoo Kalkornsurapranee, Akarapong Tuljittraporn, Arthittaya Chuaybamrung, A. V. Vijayashankar, Jobish Johns

A novel method for chemically curing natural rubber (NR) using 2,4-dihydroxybenzaldehyde (DHB) at low temperatures has been discovered. Adding varying amounts of DHB to NR increases the crosslinking between the NR molecular chains. The chemical reaction between NR molecular chains and DHB was confirmed through Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (NMR) spectra. From the thermogravimetric analysis (TGA), the thermal stability and activation energy of degradation were determined. The variation in glass transition temperature (T_g), as an indication of increased crosslink density, reducing the mobility of rubber chains, has been confirmed through differential scanning calorimetry (DSC). The addition of DHB to latex significantly enhanced the thermal stability of the rubber. An increase in the activation energy of 5.52% was observed upon the addition of 80 mL DHB into NRL when compared to the uncured one. Furthermore, the tensile properties, in terms of tensile strength and modulus of elasticity of rubber, were drastically increased through DHB crosslinking. Tensile strength values of rubber were found to increase by reducing its elongation at break due to the formation of crosslinks between the macromolecular chains. NR cured with 80 mL DHB exhibited superior tensile and thermal properties among the series of cured samples. By adding 80 mL of DHB, the tensile strength increased by 390% and the elongation at break decreased by 10%. The advantage of this curing method is that, it is an effective technique for crosslinking NR directly from NR latex at comparatively low temperature.

Graphical abstract

我们发现了一种在低温下使用 2,4-二羟基苯甲醛（DHB）对天然橡胶（NR）进行化学固化的新方法。在 NR 中加入不同量的 DHB 可增加 NR 分子链之间的交联。傅立叶变换红外光谱（FTIR）和质子核磁共振光谱（NMR）证实了 NR 分子链与 DHB 之间的化学反应。热重分析（TGA）测定了降解的热稳定性和活化能。通过差示扫描量热法（DSC）确认了玻璃化转变温度（Tg）的变化，这表明交联密度增加，降低了橡胶链的流动性。在胶乳中添加 DHB 可显著提高橡胶的热稳定性。与未固化的 NRL 相比，在 NRL 中加入 80 mL DHB 后，活化能增加了 5.52%。此外，通过 DHB 交联，橡胶的拉伸强度和弹性模量等拉伸性能也大幅提高。由于大分子链之间形成了交联，橡胶的拉伸强度值通过降低断裂伸长率而增加。在一系列硫化样品中，用 80 mL DHB 硫化的 NR 具有更优越的拉伸和热性能。加入 80 mL DHB 后，拉伸强度提高了 390%，断裂伸长率降低了 10%。这种固化方法的优点在于，它是一种在相对较低的温度下直接从 NR 胶乳中交联 NR 的有效技术。

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引用次数: 0