Pub Date : 2026-10-26DOI: 10.1016/j.polymer.2026.131008
Yanshuo Qiu, Jing Wang, Huishuang Mou, Miaokai Liu, Yijie He, Shaoli Wang, Jin Tang, Lei Lu
Polyurethane foam (PUF) is a lightweight thermal insulation material, but its performance is limited by non-uniform cell structure and inefficient heat transfer. To improve its thermal insulation and structural stability, a sprayable PUF modified with dual-scale nano-silica (nano-SiO2) and micron-sized hollow microspheres was developed and evaluated for plant protection in low-temperature environments. A mixed polyol system consisting of polycaprolactone polyol and polyether polyol was used to regulate foaming behavior and cell structure. The dual-scale fillers effectively optimized cell morphology, yielding smaller and more uniform cells, higher cell density, and thicker, more intact cell walls. Consequently, the thermal conductivity decreased from 0.0584 to 0.0373 W·m-1·K-1, corresponding to a 36% reduction. Infrared thermography and thermogravimetric analysis confirmed improved thermal insulation and thermal stability. In addition, the modified foam showed enhanced compressive modulus, load-bearing capacity, and hydrophobicity, with water contact angle increasing from 83° to approximately 104°. Low-temperature tests further demonstrated its ability to buffer temperature fluctuations in plant branches and mitigate frost damage. These results indicate that dual-scale filler modification is an effective strategy for optimizing PUF structure and heat transfer behavior, providing a reference for the design of sprayable thermal protection materials for plants in frigid environments.
{"title":"Micro/Nano Dual-Scale Engineering of Polyurethane Foam Incorporating Nano-SiO2 and Cenospheres for Frost Protection of Fruit Trees","authors":"Yanshuo Qiu, Jing Wang, Huishuang Mou, Miaokai Liu, Yijie He, Shaoli Wang, Jin Tang, Lei Lu","doi":"10.1016/j.polymer.2026.131008","DOIUrl":"https://doi.org/10.1016/j.polymer.2026.131008","url":null,"abstract":"Polyurethane foam (PUF) is a lightweight thermal insulation material, but its performance is limited by non-uniform cell structure and inefficient heat transfer. To improve its thermal insulation and structural stability, a sprayable PUF modified with dual-scale nano-silica (nano-SiO<ce:inf loc=\"post\">2</ce:inf>) and micron-sized hollow microspheres was developed and evaluated for plant protection in low-temperature environments. A mixed polyol system consisting of polycaprolactone polyol and polyether polyol was used to regulate foaming behavior and cell structure. The dual-scale fillers effectively optimized cell morphology, yielding smaller and more uniform cells, higher cell density, and thicker, more intact cell walls. Consequently, the thermal conductivity decreased from 0.0584 to 0.0373 W·m<ce:sup loc=\"post\">-1</ce:sup>·K<ce:sup loc=\"post\">-1</ce:sup>, corresponding to a 36% reduction. Infrared thermography and thermogravimetric analysis confirmed improved thermal insulation and thermal stability. In addition, the modified foam showed enhanced compressive modulus, load-bearing capacity, and hydrophobicity, with water contact angle increasing from 83° to approximately 104°. Low-temperature tests further demonstrated its ability to buffer temperature fluctuations in plant branches and mitigate frost damage. These results indicate that dual-scale filler modification is an effective strategy for optimizing PUF structure and heat transfer behavior, providing a reference for the design of sprayable thermal protection materials for plants in frigid environments.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"7 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149275016","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}
Itaconic acid-based compounds possess advantages such as renewable sources, modifiable structures, and polymerizable unsaturated bonds, making them suitable for the preparation of bio-based photosensitive resins. However, itaconic acid-based small molecules and their derivatives typically exhibit a high density of reactive groups during photopolymerization, easily resulting in significant polymerization shrinkage and dimensional deviations upon curing, which limits their application in dimensionally sensitive stereolithography (SLA) 3D printing. In this work, an itaconate-based photocurable resin (IEA) was first synthesized through the ring-opening esterification of itaconic anhydride with 2-hydroxyethyl methacrylate. Epoxidized tannic acid (TAE), another bio-derived component, was then introduced to construct an IEA/TAE hybrid photo/thermal curing system. FT-IR and 1H NMR results demonstrated that IEA retained the free-radical polymerizable methacrylate double bonds, and epoxy groups were successfully introduced into TAE. With increasing TAE content, the linear shrinkage of printed specimens with a nominal width of 10 mm decreased significantly, with IEA-TAE40 exhibiting a 52.6% reduction relative to IEA. Meanwhile, the photocurable 3D printing of complex components was successfully accomplished using IEA-TAE40, indicating that the system possesses good forming capability for complex structures. Although the introduction of TAE resulted in a slight decrease in tensile strength, IEA-TAE40 still maintained a tensile strength of 50.1 MPa, which is close to the strength level of some commercial photosensitive resins. Thermogravimetric analysis indicated that increasing the TAE content could also improve the char yield at 800 °C. The comprehensive results establish the composition–property relationships between the TAE content and the linear shrinkage, rheological behavior, network relaxation, and service stability of the printed products, and demonstrate that the incorporation of the TAE component can balance dimensional accuracy, processability, and overall mechanical performance. This study provides a viable materials-design strategy for high-performance bio-based photosensitive resins used in SLA 3D printing.
{"title":"Stereolithography 3D printing and properties of photo-thermal hybrid curing bio-based photosensitive resin","authors":"Zhansheng Hu, Rui Wang, Shaoyun Chen, Jianhong Gao, Cuifang Cai, Xiaoying Liu, Bo Qu, Xiaolin Luo, Dongxian Zhuo","doi":"10.1016/j.polymer.2026.130982","DOIUrl":"https://doi.org/10.1016/j.polymer.2026.130982","url":null,"abstract":"Itaconic acid-based compounds possess advantages such as renewable sources, modifiable structures, and polymerizable unsaturated bonds, making them suitable for the preparation of bio-based photosensitive resins. However, itaconic acid-based small molecules and their derivatives typically exhibit a high density of reactive groups during photopolymerization, easily resulting in significant polymerization shrinkage and dimensional deviations upon curing, which limits their application in dimensionally sensitive stereolithography (SLA) 3D printing. In this work, an itaconate-based photocurable resin (IEA) was first synthesized through the ring-opening esterification of itaconic anhydride with 2-hydroxyethyl methacrylate. Epoxidized tannic acid (TAE), another bio-derived component, was then introduced to construct an IEA/TAE hybrid photo/thermal curing system. FT-IR and <ce:sup loc=\"pre\">1</ce:sup>H NMR results demonstrated that IEA retained the free-radical polymerizable methacrylate double bonds, and epoxy groups were successfully introduced into TAE. With increasing TAE content, the linear shrinkage of printed specimens with a nominal width of 10 mm decreased significantly, with IEA-TAE40 exhibiting a 52.6% reduction relative to IEA. Meanwhile, the photocurable 3D printing of complex components was successfully accomplished using IEA-TAE40, indicating that the system possesses good forming capability for complex structures. Although the introduction of TAE resulted in a slight decrease in tensile strength, IEA-TAE40 still maintained a tensile strength of 50.1 MPa, which is close to the strength level of some commercial photosensitive resins. Thermogravimetric analysis indicated that increasing the TAE content could also improve the char yield at 800 °C. The comprehensive results establish the composition–property relationships between the TAE content and the linear shrinkage, rheological behavior, network relaxation, and service stability of the printed products, and demonstrate that the incorporation of the TAE component can balance dimensional accuracy, processability, and overall mechanical performance. This study provides a viable materials-design strategy for high-performance bio-based photosensitive resins used in SLA 3D printing.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"90 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149275179","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}
Polyethylene terephthalate (PET) possesses intrinsic hydrophobicity and extremely high surface resistivity, which easily triggers static charge accumulation and limits its advanced applications in transparent films and electronic packaging. Herein, we report a molecular structural regulation strategy to incorporate flexible diethylene glycol-derived ether linkages and rigid bio-based 2,5-furandicarboxylic acid furan rings into PET backbones via melt polycondensation. This design targets humidity-responsive antistatic performance, achieving high mechanical stiffness while retaining favorable optical transparency. Systematic evaluation balancing static dissipation, stiffness, and optical transparency identifies PED60F80 as the most well-balanced formulation. At 90% relative humidity, its surface resistivity declines to the order of 108 Ω, accompanied by an 86.77% reduction in electrostatic voltage relative to neat PET. Adsorbed water molecules form dynamic internal hydrogen-bond networks that facilitate rapid static-charge dissipation. Strong Coulombic intermolecular interactions between polyester chains and water molecules generate highly stable hydrogen-bonded networks, providing the fundamental origin of the enhanced moisture capture capacity. This dual-modification copolymerization route provides a facile method to prepare transparent antistatic copolyesters, and advances the fundamental comprehension of water-polymer interfacial interactions that dominate humidity-dependent antistatic behavior.
{"title":"Copolyesters Tuned by Ether Linkages and Bio-Derived Furan Rings: Humidity-Responsive Antistatic Performance with High Stiffness and Optical Clarity","authors":"Ruiyu Zhang, Hongbing Wang, Yifei Ding, Hongsheng Ding, Yongping Bai, Shuai Sun","doi":"10.1016/j.polymer.2026.131023","DOIUrl":"https://doi.org/10.1016/j.polymer.2026.131023","url":null,"abstract":"Polyethylene terephthalate (PET) possesses intrinsic hydrophobicity and extremely high surface resistivity, which easily triggers static charge accumulation and limits its advanced applications in transparent films and electronic packaging. Herein, we report a molecular structural regulation strategy to incorporate flexible diethylene glycol-derived ether linkages and rigid bio-based 2,5-furandicarboxylic acid furan rings into PET backbones via melt polycondensation. This design targets humidity-responsive antistatic performance, achieving high mechanical stiffness while retaining favorable optical transparency. Systematic evaluation balancing static dissipation, stiffness, and optical transparency identifies PED<ce:inf loc=\"post\">60</ce:inf>F<ce:inf loc=\"post\">80</ce:inf> as the most well-balanced formulation. At 90% relative humidity, its surface resistivity declines to the order of 10<ce:sup loc=\"post\">8</ce:sup> Ω, accompanied by an 86.77% reduction in electrostatic voltage relative to neat PET. Adsorbed water molecules form dynamic internal hydrogen-bond networks that facilitate rapid static-charge dissipation. Strong Coulombic intermolecular interactions between polyester chains and water molecules generate highly stable hydrogen-bonded networks, providing the fundamental origin of the enhanced moisture capture capacity. This dual-modification copolymerization route provides a facile method to prepare transparent antistatic copolyesters, and advances the fundamental comprehension of water-polymer interfacial interactions that dominate humidity-dependent antistatic behavior.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"6 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149275156","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}
Pub Date : 2026-10-26DOI: 10.1016/j.polymer.2026.131024
Yuqun Du, Chenyu Zhang, Mingqi Yang, Qiaoling Li, Hongxia Yan
The development of nonconventional luminophores with long-wavelength emission and high quantum yield (QY) remains a significant challenge. Herein, we report a hyperbranched polysiloxane (P1) and its N-isopropylacrylamide functionalized derivative (P1-NIPAM). The latter exhibits multicolor emission from blue to yellow-green and to orange-red, with an elevated QY of 14.7%. The fluorescence of P1-NIPAM is remarkably enhanced compared to that of P1 at a lower concentration. The polyacrylamide film doped with P1-NIPAM exhibits strong fluorescence under 365 nm UV irradiation. Moreover, P1-NIPAM effectively illuminates S. aureus, demonstrating its promise as a fluorescence probe for bioimaging. Theoretical calculations and experimental results reveal that the enhanced and red-shifted emission in P1-NIPAM can be attributed to the through-space n-π interactions induced by the introduction of the amide groups. This work presents a strategy for the rational design of nonconventional luminophores with long-wavelength emission and broadens their potential applications.
{"title":"Functionalized hyperbranched polysiloxanes with enhanced nonconventional luminescence for bacterial imaging","authors":"Yuqun Du, Chenyu Zhang, Mingqi Yang, Qiaoling Li, Hongxia Yan","doi":"10.1016/j.polymer.2026.131024","DOIUrl":"https://doi.org/10.1016/j.polymer.2026.131024","url":null,"abstract":"The development of nonconventional luminophores with long-wavelength emission and high quantum yield (QY) remains a significant challenge. Herein, we report a hyperbranched polysiloxane (P1) and its N-isopropylacrylamide functionalized derivative (P1-NIPAM). The latter exhibits multicolor emission from blue to yellow-green and to orange-red, with an elevated QY of 14.7%. The fluorescence of P1-NIPAM is remarkably enhanced compared to that of P1 at a lower concentration. The polyacrylamide film doped with P1-NIPAM exhibits strong fluorescence under 365 nm UV irradiation. Moreover, P1-NIPAM effectively illuminates <ce:italic>S. aureus,</ce:italic> demonstrating its promise as a fluorescence probe for bioimaging. Theoretical calculations and experimental results reveal that the enhanced and red-shifted emission in P1-NIPAM can be attributed to the through-space n-π interactions induced by the introduction of the amide groups. This work presents a strategy for the rational design of nonconventional luminophores with long-wavelength emission and broadens their potential applications.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"85 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149275157","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}
Pub Date : 2026-10-26DOI: 10.1016/j.polymer.2026.131020
Qianyu Zhao, Shaokui Cao, Yao Wang, Xinxin Zhang, Juan Li, Yanshuang Liu, Haoyan Meng, Yingliang Liu, Yadong Wang
Organic-inorganic hybrid perovskites have emerged as promising candidates for resistive switching (RS) memories due to their superior optoelectronic properties and solution processability. Nevertheless, moisture, oxygen and thermal stress induce performance degradation, greatly limiting the practical applications of these devices. In this work, we address these critical challenges by integrating upconversion nanoparticles (UCNPs) into the perovskite active layer and employing polymer passivation layers, achieving significantly enhanced device stability together with distinct near-infrared (NIR) photoresponse capabilities. This dual-functional design strategy combines polymer passivation for stability enhancement and upconversion-enabled optical control for functional extension. Poly(methyl methacrylate) (PMMA) and polystyrene (PS) with two different molecular weights are employed as passivation layers. Among all devices, PMMA-120000 exhibits superior RS performance. It delivers a maximum ON/OFF ratio of 105, a retention time of 104 s, an endurance of 500 cycles and a fast response time of 50 ns. Impressively, its ON/OFF ratio is substantially higher than that of the unpassivated devices (102). The carbonyl groups in PMMA coordinate with the perovskite layer. This interlayer supramolecular interaction effectively passivates defect states, enhancing RS performance and significantly improving environmental stability. Notably, the device maintains stable switching behavior even after 180 days of ambient storage, while also exhibiting excellent thermal stability and moisture resistance. Importantly, leveraging the upconversion property of UCNPs, the device demonstrates a pronounced photoresponse to 1550 nm NIR light, enabling NIR light-assisted RS with multilevel storage capability. These results indicate that the PMMA-passivated UCNP-MAPbI3 devices are promising candidates for high-performance, high-stability, NIR-responsive flexible resistive memory applications.
{"title":"Interlayer supramolecular interaction between perovskite and polymer to improve the switching performance in upconversion light-controlled resistive memories","authors":"Qianyu Zhao, Shaokui Cao, Yao Wang, Xinxin Zhang, Juan Li, Yanshuang Liu, Haoyan Meng, Yingliang Liu, Yadong Wang","doi":"10.1016/j.polymer.2026.131020","DOIUrl":"https://doi.org/10.1016/j.polymer.2026.131020","url":null,"abstract":"Organic-inorganic hybrid perovskites have emerged as promising candidates for resistive switching (RS) memories due to their superior optoelectronic properties and solution processability. Nevertheless, moisture, oxygen and thermal stress induce performance degradation, greatly limiting the practical applications of these devices. In this work, we address these critical challenges by integrating upconversion nanoparticles (UCNPs) into the perovskite active layer and employing polymer passivation layers, achieving significantly enhanced device stability together with distinct near-infrared (NIR) photoresponse capabilities. This dual-functional design strategy combines polymer passivation for stability enhancement and upconversion-enabled optical control for functional extension. Poly(methyl methacrylate) (PMMA) and polystyrene (PS) with two different molecular weights are employed as passivation layers. Among all devices, PMMA-120000 exhibits superior RS performance. It delivers a maximum ON/OFF ratio of 10<ce:sup loc=\"post\">5</ce:sup>, a retention time of 10<ce:sup loc=\"post\">4</ce:sup> s, an endurance of 500 cycles and a fast response time of 50 ns. Impressively, its ON/OFF ratio is substantially higher than that of the unpassivated devices (10<ce:sup loc=\"post\">2</ce:sup>). The carbonyl groups in PMMA coordinate with the perovskite layer. This interlayer supramolecular interaction effectively passivates defect states, enhancing RS performance and significantly improving environmental stability. Notably, the device maintains stable switching behavior even after 180 days of ambient storage, while also exhibiting excellent thermal stability and moisture resistance. Importantly, leveraging the upconversion property of UCNPs, the device demonstrates a pronounced photoresponse to 1550 nm NIR light, enabling NIR light-assisted RS with multilevel storage capability. These results indicate that the PMMA-passivated UCNP-MAPbI<ce:inf loc=\"post\">3</ce:inf> devices are promising candidates for high-performance, high-stability, NIR-responsive flexible resistive memory applications.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"21 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149275155","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}
Pub Date : 2026-10-24DOI: 10.1016/j.polymer.2026.131019
Shiqi Huang, Yu Meng, Hui Gou, Peipei Guo, Hai Fu, Wei Cui
Temperature-switchable flexible conductive materials, which exhibit drastic changes in both conductivity and adhesion, hold great promise for flexible sensors and capacitors. However, independently tuning post-transition mechanical and adhesive properties without sacrificing conductivity contrast remains challenging. Herein, we introduced a phase change hydrogel composed of polyacrylamide (PAM) and hydrated salt phase change material sodium acetate trihydrate (SAT) regulated by sulfobetaine methacrylate (SBMA). The incorporation of SBMA can affect the size of hydrated salt crystals within the gel network, enabling systematic tuning of the gel's mechanical properties and adhesion strength upon phase transition, while retaining a reversible conductivity on/off switching ratio of approximately 104 between the crystallized and molten states of SAT in the hydrogel. Upon phase transition, the gel retains excellent flexibility and exhibits enhanced adhesion to various substrates. Leveraging these features, the material acts as a temperature-gated switch for both sensing and capacitor applications: the high-conductivity molten state enables signal transmission and charge storage, whereas the low-conductivity crystallized state suppresses leakage current. The combination of tunable post-transition mechanical properties and enhanced adhesion ensures reliable device integration.
{"title":"A phase-change hydrogel with phase-transition-induced 104-fold conductivity switching, retained flexibility, and switchable adhesion for thermal-gated electronics","authors":"Shiqi Huang, Yu Meng, Hui Gou, Peipei Guo, Hai Fu, Wei Cui","doi":"10.1016/j.polymer.2026.131019","DOIUrl":"https://doi.org/10.1016/j.polymer.2026.131019","url":null,"abstract":"Temperature-switchable flexible conductive materials, which exhibit drastic changes in both conductivity and adhesion, hold great promise for flexible sensors and capacitors. However, independently tuning post-transition mechanical and adhesive properties without sacrificing conductivity contrast remains challenging. Herein, we introduced a phase change hydrogel composed of polyacrylamide (PAM) and hydrated salt phase change material sodium acetate trihydrate (SAT) regulated by sulfobetaine methacrylate (SBMA). The incorporation of SBMA can affect the size of hydrated salt crystals within the gel network, enabling systematic tuning of the gel's mechanical properties and adhesion strength upon phase transition, while retaining a reversible conductivity on/off switching ratio of approximately 10<ce:sup loc=\"post\">4</ce:sup> between the crystallized and molten states of SAT in the hydrogel. Upon phase transition, the gel retains excellent flexibility and exhibits enhanced adhesion to various substrates. Leveraging these features, the material acts as a temperature-gated switch for both sensing and capacitor applications: the high-conductivity molten state enables signal transmission and charge storage, whereas the low-conductivity crystallized state suppresses leakage current. The combination of tunable post-transition mechanical properties and enhanced adhesion ensures reliable device integration.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"84 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2026-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149275182","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}
Pub Date : 2026-10-24DOI: 10.1016/j.polymer.2026.131016
Antonio Vittoria, Viviana Losciale, Giuseppe Antinucci, Giuseppe Femina, Daniele Tammaro, Vincenzo Busico, Odda Ruiz de Ballesteros, Finizia Auriemma, Roberta Cipullo
Polyolefin graft copolymers have recently emerged as promising compatibilizers for immiscible polyethylene/isotactic polypropylene (PE/iPP) blends. Although graft length and graft density have been identified as key architectural parameters, the role of the chemical nature and crystallizability of PE grafts remains poorly understood. Here, we report the targeted synthesis of architecture-controlled iPP-g-(L)PE graft copolymers, where (L)PE denotes either HDPE-like or LLDPE-like PE side chains. Allyl-terminated PE macromonomers were obtained through high-throughput screening of a catalyst library, enabling access to macromonomers with predefined molar mass and microstructure, and were subsequently copolymerized with propene using an isotactic-selective pyridylamido-Hf catalyst. An integrated characterization protocol combining quantitative 13C NMR spectroscopy, high-temperature GPC, analytical crystallization elution fractionation (CEF), DSC, and WAXS enabled a quantitative description of graft architecture, including graft copolymer content, graft number, iPP spacer length, and crystallization behavior. Selected iPP-g-HDPE and iPP-g-LLDPE copolymers were evaluated as compatibilizers for HDPE-rich PE/iPP blends at loadings of only 1–3 wt%. Under these conditions, the HDPE-grafted copolymers transformed a brittle blend with elongation at break below 10% into highly ductile materials with elongations at break of approximately 750–1500%, depending on graft architecture and cooling protocol. SEM analysis revealed a lower density of fracture-induced interfacial voids and extensive fibrillation at the phase boundary, indicative of improved adhesion between the PE and iPP phases and more efficient stress transfer across the interface. In contrast, the iPP-g-LLDPE analogue, despite containing long branches and a high graft density, exhibited significantly lower compatibilization efficiency and absence of interfacial fibrillation. These results indicate that compatibilization efficiency is not governed by graft length and graft number alone. Within the investigated architecture, the ability of the PE side chains to crystallize emerges as an additional molecular design parameter for efficient PE/iPP graft compatibilizers, suggesting a significant contribution of crystallization-assisted interfacial anchoring.
{"title":"iPP-g-(L)PE Graft Copolymers for PE/iPP Compatibilization: Role of PE Side-Chain Crystallizability","authors":"Antonio Vittoria, Viviana Losciale, Giuseppe Antinucci, Giuseppe Femina, Daniele Tammaro, Vincenzo Busico, Odda Ruiz de Ballesteros, Finizia Auriemma, Roberta Cipullo","doi":"10.1016/j.polymer.2026.131016","DOIUrl":"https://doi.org/10.1016/j.polymer.2026.131016","url":null,"abstract":"Polyolefin graft copolymers have recently emerged as promising compatibilizers for immiscible polyethylene/isotactic polypropylene (PE/iPP) blends. Although graft length and graft density have been identified as key architectural parameters, the role of the chemical nature and crystallizability of PE grafts remains poorly understood. Here, we report the targeted synthesis of architecture-controlled iPP-<ce:italic>g</ce:italic>-(L)PE graft copolymers, where (L)PE denotes either HDPE-like or LLDPE-like PE side chains. Allyl-terminated PE macromonomers were obtained through high-throughput screening of a catalyst library, enabling access to macromonomers with predefined molar mass and microstructure, and were subsequently copolymerized with propene using an isotactic-selective pyridylamido-Hf catalyst. An integrated characterization protocol combining quantitative <ce:sup loc=\"pre\">13</ce:sup>C NMR spectroscopy, high-temperature GPC, analytical crystallization elution fractionation (CEF), DSC, and WAXS enabled a quantitative description of graft architecture, including graft copolymer content, graft number, iPP spacer length, and crystallization behavior. Selected iPP-<ce:italic>g</ce:italic>-HDPE and iPP-<ce:italic>g</ce:italic>-LLDPE copolymers were evaluated as compatibilizers for HDPE-rich PE/iPP blends at loadings of only 1–3 wt%. Under these conditions, the HDPE-grafted copolymers transformed a brittle blend with elongation at break below 10% into highly ductile materials with elongations at break of approximately 750–1500%, depending on graft architecture and cooling protocol. SEM analysis revealed a lower density of fracture-induced interfacial voids and extensive fibrillation at the phase boundary, indicative of improved adhesion between the PE and iPP phases and more efficient stress transfer across the interface. In contrast, the iPP-<ce:italic>g</ce:italic>-LLDPE analogue, despite containing long branches and a high graft density, exhibited significantly lower compatibilization efficiency and absence of interfacial fibrillation. These results indicate that compatibilization efficiency is not governed by graft length and graft number alone. Within the investigated architecture, the ability of the PE side chains to crystallize emerges as an additional molecular design parameter for efficient PE/iPP graft compatibilizers, suggesting a significant contribution of crystallization-assisted interfacial anchoring.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"23 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2026-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149275183","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}
Tailoring the spatial orientation of anisotropic nanofillers provides an effective approach for controlling the nanoscale mechanical behaviour of polymer nanocomposites; however, the influence of rotating magnetic-field-assisted GNP orientation on local mechanical and viscoelastic responses remains insufficiently explored. In this study, the effect of magnetic-field-assisted alignment of graphene nanoplatelets (GNPs) on the nanoscale mechanical and viscoelastic behaviour of GNP/epoxy composites is systematically investigated. XRD analysis was initially employed to identify the optimum GNP concentration based on filler dispersion. The selected nanocomposites were subsequently fabricated under a rotating magnetic field in lateral and transverse configurations, with the transverse configuration examined at different orientation angles. The resulting filler orientation and morphology were characterized using HR-SEM and tapping-mode atomic force microscopy (AFM), while nanoindentation and accelerated property mapping were employed to evaluate the spatially resolved mechanical response. The results demonstrate that magnetic-field-assisted processing produces preferential GNP orientation and modifies the spatial distribution of nanoscale stiffness and energy dissipation. Among the investigated configurations, the RF-T45 sample exhibited the most pronounced nanoscale mechanical response, with approximately 42% and 100% increases in hardness and reduced modulus, relative to the reference condition. The AFM-derived viscoelastic maps further revealed reduced energy dissipation and improved nanoscale mechanical homogeneity associated with controlled filler organization. The combined HR-SEM, AFM, nanoindentation, and property-mapping results establish a direct relationship between magnetic-field-induced GNP orientation and the spatially resolved mechanical and viscoelastic response of the nanocomposite. The study demonstrates that controlling GNP orientation through transverse rotating magnetic fields provides a viable strategy for tailoring nanoscale reinforcement and mechanical heterogeneity in epoxy-based polymer nanocomposites.
{"title":"Tailoring the nanoscale mechanical behaviour of Epoxy nanocomposites using magnetic-field-assisted alignment of graphene nanoplatelets","authors":"Amitha Ajith, Ramanujam Sarathi, Shankar Krishnapillai, Ramachandran Velmurugan, Ganesan Krupanandam, Gandluri Parameswarreddy","doi":"10.1016/j.polymer.2026.130969","DOIUrl":"https://doi.org/10.1016/j.polymer.2026.130969","url":null,"abstract":"Tailoring the spatial orientation of anisotropic nanofillers provides an effective approach for controlling the nanoscale mechanical behaviour of polymer nanocomposites; however, the influence of rotating magnetic-field-assisted GNP orientation on local mechanical and viscoelastic responses remains insufficiently explored. In this study, the effect of magnetic-field-assisted alignment of graphene nanoplatelets (GNPs) on the nanoscale mechanical and viscoelastic behaviour of GNP/epoxy composites is systematically investigated. XRD analysis was initially employed to identify the optimum GNP concentration based on filler dispersion. The selected nanocomposites were subsequently fabricated under a rotating magnetic field in lateral and transverse configurations, with the transverse configuration examined at different orientation angles. The resulting filler orientation and morphology were characterized using HR-SEM and tapping-mode atomic force microscopy (AFM), while nanoindentation and accelerated property mapping were employed to evaluate the spatially resolved mechanical response. The results demonstrate that magnetic-field-assisted processing produces preferential GNP orientation and modifies the spatial distribution of nanoscale stiffness and energy dissipation. Among the investigated configurations, the RF-T45 sample exhibited the most pronounced nanoscale mechanical response, with approximately 42% and 100% increases in hardness and reduced modulus, relative to the reference condition. The AFM-derived viscoelastic maps further revealed reduced energy dissipation and improved nanoscale mechanical homogeneity associated with controlled filler organization. The combined HR-SEM, AFM, nanoindentation, and property-mapping results establish a direct relationship between magnetic-field-induced GNP orientation and the spatially resolved mechanical and viscoelastic response of the nanocomposite. The study demonstrates that controlling GNP orientation through transverse rotating magnetic fields provides a viable strategy for tailoring nanoscale reinforcement and mechanical heterogeneity in epoxy-based polymer nanocomposites.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"7 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2026-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149274938","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}
Pub Date : 2026-10-24DOI: 10.1016/j.polymer.2026.130980
Massimo Christian D’Alterio, Lorenzo Lombardi, Alessandra Cicolella, Antonio Ascione, Sonia Stornaiuolo, Pier Luca Maffettone, Claudio De Rosa, Rocco Di Girolamo
The formation of poly(lactic acid) (PLA) stereocomplex (SC) represents an effective strategy to enhance the crystallization behavior and thermomechanical performance of PLA-based materials. We show that the crystallization of the PLA stereocomplex can be induced in melt crystallization by suitable melt-extrusion processing of blends even composed of high molecular mass samples of the two enantiomeric components PDLA and PLLA (Mw > 100 Kg/mol) and of blends of enantiopure poly(D-lactic acid) (PDLA) and stereodefective poly(L-lactic acid) (PLLA) containing up to 12% D-lactide defects. Moreover, we demonstrate that the SC crystallites formed in situ during melt extrusion act as efficient nucleating agent for the crystallization of the α form of PLA. Samples of PDLA/PLLA blends with different composition and stereoregularity of the PLLA component were prepared at different extrusion temperatures and characterized by differential scanning calorimetry (DSC) and X-ray diffraction. The results demonstrate that melt extrusion induces crystallization of SC even in highly stereodefective systems, with the extent and thermal stability of the SC phase strongly depending on both blend composition and processing conditions. Increasing the stereodefects content progressively reduced SC crystal perfection and melting temperature (from 220°C to 190 °C). Despite their limited concentration, SC crystallites exhibited a remarkable nucleating effect on the crystallization of the α form of PLA. Nucleation efficiencies, evaluated through self-nucleation protocols, ranged from ∼60% up to values approaching 100%, depending on stereoregularity and blend composition. The strongest nucleating effect was observed in blends containing moderately stereodefective PLLA, where residual unmelted SC crystallites efficiently promoted α-form crystallization during cooling. These findings demonstrate that SC crystals generated directly during extrusion can act as highly effective nucleating agent without requiring additional compounding with conventional nucleants. The proposed strategy offers a practical route to tailor crystallization kinetics and crystalline morphology in industrially relevant PLA systems of high molecular mass while preserving the fully bio-based nature of the material.
聚乳酸（PLA）立体配合物（SC）的形成是提高PLA基材料结晶性能和热机械性能的有效策略。研究结果表明，通过适当的熔融挤压工艺，即使由两种对映体成分PDLA和PLLA（分子量为100 Kg/mol）的高分子量样品组成的共混物，以及含有高达12% d -乳酸缺陷的对映纯聚d -乳酸（PDLA）和立体缺陷聚l -乳酸（PLLA）的共混物，也可以诱导PLA立体配合物的熔融结晶。此外，我们还证明了在熔融挤压过程中原位形成的SC晶体作为α型聚乳酸结晶的有效成核剂。在不同的挤出温度下制备了具有不同PLLA组分组成和立体规则度的PDLA/PLLA共混物样品，并用差示扫描量热法（DSC）和x射线衍射对其进行了表征。结果表明，即使在高度立体缺陷的体系中，熔体挤压也会引起SC相的结晶，而SC相的程度和热稳定性在很大程度上取决于共混物组成和加工条件。增加立体缺陷含量会逐渐降低SC晶体的完美度和熔化温度（从220°C到190°C）。尽管SC的浓度有限，但它们对聚乳酸的α型结晶具有显著的成核作用。通过自成核方案评估的成核效率范围从~ 60%到接近100%，取决于立体规则性和混合成分。在含有中度立体缺陷PLLA的共混物中观察到最强的成核效应，其中残余的未熔化SC晶在冷却过程中有效地促进了α-型结晶。这些发现表明，在挤压过程中直接产生的SC晶体可以作为高效的成核剂，而无需与常规成核剂额外复合。提出的策略提供了一种实用的途径，可以在工业相关的高分子质量PLA系统中定制结晶动力学和晶体形态，同时保留材料的完全生物基性质。
{"title":"Melt Extrusion of High Molecular Weight Stereodefective PLLA/PDLA Blends: In Situ Stereocomplex Formation and Nucleation Effect","authors":"Massimo Christian D’Alterio, Lorenzo Lombardi, Alessandra Cicolella, Antonio Ascione, Sonia Stornaiuolo, Pier Luca Maffettone, Claudio De Rosa, Rocco Di Girolamo","doi":"10.1016/j.polymer.2026.130980","DOIUrl":"https://doi.org/10.1016/j.polymer.2026.130980","url":null,"abstract":"The formation of poly(lactic acid) (PLA) stereocomplex (SC) represents an effective strategy to enhance the crystallization behavior and thermomechanical performance of PLA-based materials. We show that the crystallization of the PLA stereocomplex can be induced in melt crystallization by suitable melt-extrusion processing of blends even composed of high molecular mass samples of the two enantiomeric components PDLA and PLLA (<ce:italic>M</ce:italic><ce:inf loc=\"post\">w</ce:inf> > 100 Kg/mol) and of blends of enantiopure poly(D-lactic acid) (PDLA) and stereodefective poly(L-lactic acid) (PLLA) containing up to 12% D-lactide defects. Moreover, we demonstrate that the SC crystallites formed <ce:italic>in situ</ce:italic> during melt extrusion act as efficient nucleating agent for the crystallization of the α form of PLA. Samples of PDLA/PLLA blends with different composition and stereoregularity of the PLLA component were prepared at different extrusion temperatures and characterized by differential scanning calorimetry (DSC) and X-ray diffraction. The results demonstrate that melt extrusion induces crystallization of SC even in highly stereodefective systems, with the extent and thermal stability of the SC phase strongly depending on both blend composition and processing conditions. Increasing the stereodefects content progressively reduced SC crystal perfection and melting temperature (from 220°C to 190 °C). Despite their limited concentration, SC crystallites exhibited a remarkable nucleating effect on the crystallization of the α form of PLA. Nucleation efficiencies, evaluated through self-nucleation protocols, ranged from ∼60% up to values approaching 100%, depending on stereoregularity and blend composition. The strongest nucleating effect was observed in blends containing moderately stereodefective PLLA, where residual unmelted SC crystallites efficiently promoted α-form crystallization during cooling. These findings demonstrate that SC crystals generated directly during extrusion can act as highly effective nucleating agent without requiring additional compounding with conventional nucleants. The proposed strategy offers a practical route to tailor crystallization kinetics and crystalline morphology in industrially relevant PLA systems of high molecular mass while preserving the fully bio-based nature of the material.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"13 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2026-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149275184","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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