Polymer最新文献_第8页

Dynamics of hydrogen-bonded polymer complexes of poly(ether oxide) and poly(acrylic acid): time-humidity-temperature equivalence

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-01-27 DOI: 10.1016/j.polymer.2025.128080

Zexin Liu, Hao Huang, Peiyang Yin, Caihong Zhang, Shuguang Yang

The dynamics of polymer complexes over long-time scales are critical for their applications across various fields. Humidity is a very important environmental parameter and its coupling with temperature significantly affects the performance of polymer complex materials. However, the understanding of humidity effect on hydrogen-bonded polymer complex is poor and the quantitative studies are lacking. Here, we investigate the static and dynamic mechanical properties of hydrogen-bonded polymer complexes of poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) and its reinforced derivatives under different humidity and temperature. When PEO/PAA complexes are reinforced through covalent cross-linking and coordination, both the humidity-induced glass transition and the glass transition temperature (T_g) increase. The equilibrium water uptake as a function of relative humidity (RH) shows two distinct trends, and the trend transition corresponds to the humidity-induced glass transition. Time-humidity equivalence and time-temperature equivalence are applied separately to construct the master curves. The temperature-dependent shift factor (a_T) is fitted to Arrhenius and Williams-Landel-Ferry (WLF) equations before and after T_g, respectively. Instead of the value of RH, the equilibrium water ratio in the polymer complex is used to describe humidity-dependent shift factor (a_W), which fits two log-linear equations before and after humidity-induced glass transition. Furthermore, we combine humidity and temperature to do superposition to build the master curve of much longer timescale, and propose a coefficient (f_c) to describe how the temperature and humidity working together and coupling effect.

{"title":"Dynamics of hydrogen-bonded polymer complexes of poly(ether oxide) and poly(acrylic acid): time-humidity-temperature equivalence","authors":"Zexin Liu, Hao Huang, Peiyang Yin, Caihong Zhang, Shuguang Yang","doi":"10.1016/j.polymer.2025.128080","DOIUrl":"10.1016/j.polymer.2025.128080","url":null,"abstract":"<div><div>The dynamics of polymer complexes over long-time scales are critical for their applications across various fields. Humidity is a very important environmental parameter and its coupling with temperature significantly affects the performance of polymer complex materials. However, the understanding of humidity effect on hydrogen-bonded polymer complex is poor and the quantitative studies are lacking. Here, we investigate the static and dynamic mechanical properties of hydrogen-bonded polymer complexes of poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) and its reinforced derivatives under different humidity and temperature. When PEO/PAA complexes are reinforced through covalent cross-linking and coordination, both the humidity-induced glass transition and the glass transition temperature (<em>T</em><sub>g</sub>) increase. The equilibrium water uptake as a function of relative humidity (RH) shows two distinct trends, and the trend transition corresponds to the humidity-induced glass transition. Time-humidity equivalence and time-temperature equivalence are applied separately to construct the master curves. The temperature-dependent shift factor (<em>a</em><sub>T</sub>) is fitted to Arrhenius and Williams-Landel-Ferry (WLF) equations before and after <em>T</em><sub>g</sub>, respectively. Instead of the value of RH, the equilibrium water ratio in the polymer complex is used to describe humidity-dependent shift factor (<em>a</em><sub>W</sub>), which fits two log-linear equations before and after humidity-induced glass transition. Furthermore, we combine humidity and temperature to do superposition to build the master curve of much longer timescale, and propose a coefficient (<em>f</em><sub>c</sub>) to describe how the temperature and humidity working together and coupling effect.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128080"},"PeriodicalIF":4.1,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143044387","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}

引用次数: 0

Computational study of active polar polymer melts: From active reptation to activity induced local alignment

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-01-25 DOI: 10.1016/j.polymer.2025.128074

Javier Oller-Iscar , Andrés R. Tejedor , Marisol Ripoll , Jorge Ramírez

This work investigates the effects of tangent polar activity on the conformational and dynamic properties of entangled polymer melts through Langevin molecular dynamics simulations. We examine systems composed of all self-propelled, monodisperse linear chains, so that constraint release is considered. The range of activities explored here includes values where the active reptation theory is applicable, as well as higher activities that challenge the validity of the theory. Chain conformations exhibit a moderate increase in coil size increase, which becomes more pronounced at higher activity levels. Under these conditions, a local bond alignment along the chain contour appears together with a non-homogeneous segmental stretching, and orientation and stretching of the tube. Dynamically, polar activity induces a molecular-weight-independent diffusion coefficient, a transient superdiffusive behavior, and an end-to-end relaxation time inversely proportional to the molecular weight. Finally, our results are summarized in a diagram that classifies the various regimes of behavior observed in the simulations. Overall, these findings provide valuable insights into the complex interplay between activity and entanglements, advancing our understanding of active polymer systems and their potential applications across various fields.

{"title":"Computational study of active polar polymer melts: From active reptation to activity induced local alignment","authors":"Javier Oller-Iscar , Andrés R. Tejedor , Marisol Ripoll , Jorge Ramírez","doi":"10.1016/j.polymer.2025.128074","DOIUrl":"10.1016/j.polymer.2025.128074","url":null,"abstract":"<div><div>This work investigates the effects of tangent polar activity on the conformational and dynamic properties of entangled polymer melts through Langevin molecular dynamics simulations. We examine systems composed of all self-propelled, monodisperse linear chains, so that constraint release is considered. The range of activities explored here includes values where the active reptation theory is applicable, as well as higher activities that challenge the validity of the theory. Chain conformations exhibit a moderate increase in coil size increase, which becomes more pronounced at higher activity levels. Under these conditions, a local bond alignment along the chain contour appears together with a non-homogeneous segmental stretching, and orientation and stretching of the tube. Dynamically, polar activity induces a molecular-weight-independent diffusion coefficient, a transient superdiffusive behavior, and an end-to-end relaxation time inversely proportional to the molecular weight. Finally, our results are summarized in a diagram that classifies the various regimes of behavior observed in the simulations. Overall, these findings provide valuable insights into the complex interplay between activity and entanglements, advancing our understanding of active polymer systems and their potential applications across various fields.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128074"},"PeriodicalIF":4.1,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031184","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}

引用次数: 0

Easy synthesis of self-healing thermoplastic elastomer (TPE) via functionalization of styrene block copolymer (SEBS) with a cyclic amine compound in melt state and rheological assessment of non-covalent dynamic interactions

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-01-25 DOI: 10.1016/j.polymer.2025.128083

Mine Begum Alanalp, Ali Durmus

In this study, an amine functionalized thermoplastic elastomer was easily synthesized by a semi-batch reactive melt compounding method in an internal mixer at 165 °C using maleic anhydride grafted styrene-block-ethylene/butylene-block-styrene copolymer (SEBS-g-MAh) as elastomer phase and 3-amino-1,2,4-triazole (TA) as cyclic amine compound. Then a metal salt, zinc nitrate (Zn(NO₃)₂), was introduced into the melt mixer to form metal-ligand interactions between amine functionalized TPE. Structural, mechanical, rheological, and viscoelastic properties of functional TPE were characterized by various analytical methods such as FTIR, DMA, rotational rheometer, and tensile test. FTIR analysis confirmed that the primary amine groups of cyclic amine compound reacted with maleic anhydride of SEBS-g-MAh to form maleimid groups. Formation of metal-ligand interactions in the modified TPE structure was also shown with various rheological measurements such as strain-dependent, frequency-dependent, and time-dependent test procedures and different mathematical models. It was shown that the strong metal-ligand interactions provided the modified TPE, temperature-induced self-healing property.

{"title":"Easy synthesis of self-healing thermoplastic elastomer (TPE) via functionalization of styrene block copolymer (SEBS) with a cyclic amine compound in melt state and rheological assessment of non-covalent dynamic interactions","authors":"Mine Begum Alanalp, Ali Durmus","doi":"10.1016/j.polymer.2025.128083","DOIUrl":"10.1016/j.polymer.2025.128083","url":null,"abstract":"<div><div>In this study, an amine functionalized thermoplastic elastomer was easily synthesized by a semi-batch reactive melt compounding method in an internal mixer at 165 °C using maleic anhydride grafted styrene-<em>block</em>-ethylene/butylene-<em>block</em>-styrene copolymer (SEBS-g-MAh) as elastomer phase and 3-amino-1,2,4-triazole (TA) as cyclic amine compound. Then a metal salt, zinc nitrate (Zn(NO<sub>3</sub>)<sub>2</sub>), was introduced into the melt mixer to form metal-ligand interactions between amine functionalized TPE. Structural, mechanical, rheological, and viscoelastic properties of functional TPE were characterized by various analytical methods such as FTIR, DMA, rotational rheometer, and tensile test. FTIR analysis confirmed that the primary amine groups of cyclic amine compound reacted with maleic anhydride of SEBS-g-MAh to form maleimid groups. Formation of metal-ligand interactions in the modified TPE structure was also shown with various rheological measurements such as strain-dependent, frequency-dependent, and time-dependent test procedures and different mathematical models. It was shown that the strong metal-ligand interactions provided the modified TPE, temperature-induced self-healing property.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128083"},"PeriodicalIF":4.1,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031182","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}

引用次数: 0

Adsorption and diffusion of a polymer chain within a thin slit composed of two patch-patterned surfaces

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-01-25 DOI: 10.1016/j.polymer.2025.128084

Pu Zhou , Hao-Nan Zhang , Guo-Ao Wang , Qing-Hui Yang , Hang-Kai Qi , Meng-Bo Luo

The adsorption and diffusion behaviors of a polymer chain within a narrow slit composed of two patch-patterned surfaces is studied using Langevin dynamics simulations. The surfaces consist of a neutral area interspersed with periodic attractive patches of size L and period d. The mismatch of the upper and lower surfaces is denoted by Δx and Δy along x- and y-directions. For both the perfectly matched system (Δx = Δy = 0) and the mismatched system (Δx = 0.5d, Δy = 0) with moderate sized patches, the polymer chain mainly adopts an upper-lower adsorption state, i.e., it is adsorbed on both surfaces simultaneously. However, for the mismatched system with Δx = Δy = 0.5d, a single-surface adsorption state where the polymer is adsorbed on only one surface is primarily observed. On the other hand, the polymer chain does not undergo diffusion in the matched case, but exhibits normal diffusion on a long time scale in mismatched cases. The translational diffusion coefficient increases when the patch mismatch changes from Δx = 0.5d, Δy = 0 to Δx = Δy = 0.5d, which is attributed to an increased frequency of changes in the adsorption state. The polymer chain diffuses via a patch-exchange mode, that is, it exchanges patches between an upper-lower adsorption state and a single-surface adsorption state. The effect of patch period and slit height is also studied. These findings underscore the pivotal role of patch mismatch in modulating polymer adsorption and diffusion behaviors.

{"title":"Adsorption and diffusion of a polymer chain within a thin slit composed of two patch-patterned surfaces","authors":"Pu Zhou , Hao-Nan Zhang , Guo-Ao Wang , Qing-Hui Yang , Hang-Kai Qi , Meng-Bo Luo","doi":"10.1016/j.polymer.2025.128084","DOIUrl":"10.1016/j.polymer.2025.128084","url":null,"abstract":"<div><div>The adsorption and diffusion behaviors of a polymer chain within a narrow slit composed of two patch-patterned surfaces is studied using Langevin dynamics simulations. The surfaces consist of a neutral area interspersed with periodic attractive patches of size <em>L</em> and period <em>d</em>. The mismatch of the upper and lower surfaces is denoted by Δ<em>x</em> and Δ<em>y</em> along <em>x-</em> and <em>y-</em>directions. For both the perfectly matched system (Δ<em>x</em> = Δ<em>y</em> = 0) and the mismatched system (Δ<em>x</em> = 0.5<em>d</em>, Δ<em>y</em> = 0) with moderate sized patches, the polymer chain mainly adopts an upper-lower adsorption state, i.e., it is adsorbed on both surfaces simultaneously. However, for the mismatched system with Δ<em>x</em> = Δ<em>y</em> = 0.5<em>d</em>, a single-surface adsorption state where the polymer is adsorbed on only one surface is primarily observed. On the other hand, the polymer chain does not undergo diffusion in the matched case, but exhibits normal diffusion on a long time scale in mismatched cases. The translational diffusion coefficient increases when the patch mismatch changes from Δ<em>x</em> = 0.5<em>d</em>, Δ<em>y</em> = 0 to Δ<em>x</em> = Δ<em>y</em> = 0.5<em>d</em>, which is attributed to an increased frequency of changes in the adsorption state. The polymer chain diffuses via a patch-exchange mode, that is, it exchanges patches between an upper-lower adsorption state and a single-surface adsorption state. The effect of patch period and slit height is also studied. These findings underscore the pivotal role of patch mismatch in modulating polymer adsorption and diffusion behaviors.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128084"},"PeriodicalIF":4.1,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031180","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}

引用次数: 0

One-pot solvent-free synthesis of self-catalyzed phosphorus/silicon cycloaliphatic epoxy resin with excellent flame-retardant and dielectric property

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-01-25 DOI: 10.1016/j.polymer.2025.128087

Yonghao Lv, Hongyan Li, Zhu-Bao Shao, Zhiming Jiang

Developing superior flame-retardant and low dielectric epoxy resins used in electronics remains a great challenge. Herein, two cycloaliphatic epoxy molecules (CFP, CFDP) were designed by incorporating phosphaphenanthrene (DOPO) into a cyclic silicon resin (CFS) through one-pot solvent-free process. CFP and CFDP exhibited self-catalyzed ability toward anhydride hardener (MHHPA). Both CFP/MHHPA and CFDP/MHHPA resins achieved UL-94 V-0 rating with limited oxygen index of 26.5 % and 36.5 % owning to the emission of silicon/phosphorus-containing segments in gas phase and enhancement of carbonation ability. Moreover, incorporating DOPO well-maintained the thermal stability and enhanced char yield in air, thus significantly suppressing heat release during combustion. Meanwhile, CFP and CFDP imparted epoxy resins with excellent dielectric properties. The dielectric loss of CFP/MHHPA and CFDP/MHHPA was 0.005 and 0.006 at 10 MHz, and dielectric constant was remained at 3.36. This work offers a facile and practical way to fabricate multifunctional epoxy resins used in electronic field.

{"title":"One-pot solvent-free synthesis of self-catalyzed phosphorus/silicon cycloaliphatic epoxy resin with excellent flame-retardant and dielectric property","authors":"Yonghao Lv, Hongyan Li, Zhu-Bao Shao, Zhiming Jiang","doi":"10.1016/j.polymer.2025.128087","DOIUrl":"10.1016/j.polymer.2025.128087","url":null,"abstract":"<div><div>Developing superior flame-retardant and low dielectric epoxy resins used in electronics remains a great challenge. Herein, two cycloaliphatic epoxy molecules (CFP, CFDP) were designed by incorporating phosphaphenanthrene (DOPO) into a cyclic silicon resin (CFS) through one-pot solvent-free process. CFP and CFDP exhibited self-catalyzed ability toward anhydride hardener (MHHPA). Both CFP/MHHPA and CFDP/MHHPA resins achieved UL-94 V-0 rating with limited oxygen index of 26.5 % and 36.5 % owning to the emission of silicon/phosphorus-containing segments in gas phase and enhancement of carbonation ability. Moreover, incorporating DOPO well-maintained the thermal stability and enhanced char yield in air, thus significantly suppressing heat release during combustion. Meanwhile, CFP and CFDP imparted epoxy resins with excellent dielectric properties. The dielectric loss of CFP/MHHPA and CFDP/MHHPA was 0.005 and 0.006 at 10 MHz, and dielectric constant was remained at 3.36. This work offers a facile and practical way to fabricate multifunctional epoxy resins used in electronic field.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128087"},"PeriodicalIF":4.1,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031186","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}

引用次数: 0

Study on the preparation of side-by-side micro-nano composite fibers by centrifugal spinning based on improved spinneret cavity structure

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-01-25 DOI: 10.1016/j.polymer.2025.128077

Hao Ye, Jingying Xu, Yaru Wang, Mengyao Zhao, Wanjing Li, Xianglong Li, Bin Yang

Centrifugal spinning of nanofibers has garnered significant attention due to its numerous advantages and industrial potential. However, meeting diverse needs with a single material is challenging, and the production of mixed material fibers often compromises fiber quality due to miscibility issues with different materials. Therefore, this study introduces a novel approach for efficiently preparing side-by-side micro-nano composite fibers by modifying the cavity structure of the centrifugal spinneret. Based on the experimental analysis of fiber spinnability, we derive the motion equation of polymer solution in the spinneret and analyze how the position of cavity plate influences the force exerted on the polymer solution. The optimal spinneret structure was determined through simulation of the solution motion mechanism in various types of spinnerets. Subsequently, polyvinylpyrrolidone (PVP)/ethylene oxide (PEO) composite micro-nanofibers were prepared using a centrifugal spinning device for experimental validation. The results indicate that the left and right cavity structure results in a significant disparity in flow between the two cavities at the nozzle, rendering it unsuitable for producing juxtaposed micro-nano composite fibers. The upper and lower cavity configuration does not impact the flow rate of the two cavities, making it suitable for stable and efficient preparation of side-by-side micro-nano composite fibers.

{"title":"Study on the preparation of side-by-side micro-nano composite fibers by centrifugal spinning based on improved spinneret cavity structure","authors":"Hao Ye, Jingying Xu, Yaru Wang, Mengyao Zhao, Wanjing Li, Xianglong Li, Bin Yang","doi":"10.1016/j.polymer.2025.128077","DOIUrl":"10.1016/j.polymer.2025.128077","url":null,"abstract":"<div><div>Centrifugal spinning of nanofibers has garnered significant attention due to its numerous advantages and industrial potential. However, meeting diverse needs with a single material is challenging, and the production of mixed material fibers often compromises fiber quality due to miscibility issues with different materials. Therefore, this study introduces a novel approach for efficiently preparing side-by-side micro-nano composite fibers by modifying the cavity structure of the centrifugal spinneret. Based on the experimental analysis of fiber spinnability, we derive the motion equation of polymer solution in the spinneret and analyze how the position of cavity plate influences the force exerted on the polymer solution. The optimal spinneret structure was determined through simulation of the solution motion mechanism in various types of spinnerets. Subsequently, polyvinylpyrrolidone (PVP)/ethylene oxide (PEO) composite micro-nanofibers were prepared using a centrifugal spinning device for experimental validation. The results indicate that the left and right cavity structure results in a significant disparity in flow between the two cavities at the nozzle, rendering it unsuitable for producing juxtaposed micro-nano composite fibers. The upper and lower cavity configuration does not impact the flow rate of the two cavities, making it suitable for stable and efficient preparation of side-by-side micro-nano composite fibers.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128077"},"PeriodicalIF":4.1,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031181","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}

引用次数: 0

Ultra-high Tg colorless polyimide film with balanced optical retardation and coefficient of thermal expansion for flexible display

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-01-25 DOI: 10.1016/j.polymer.2025.128085

Nafeesa Mushtaq, Yujie Zhang, Maria Nazir, Liyun Tan, Guofei Chen, Xingzhong Fang

Traditional colorless polyimide (CPI) films often have high coefficient of thermal expansion (CTE), high optical retardation (R_th) or low glass transition temperature (T_g) values. However, it remains challengeable to establish a balance between low R_th and low CTE without sacrificing the high T_g of CPI film for flexible display applications, especially for flexible thin-film-transistor liquid-crystal display (TFT-LCD) substrate. A set of colorless polyimides films are prepared from copolymerization of alicyclic dianhydrides hydrogenated pyromellitic dianhydride (HPMDA) and cyclopentanone bis-spironorbornane tetracarboxylic dianhydride (CpODA) with aromatic diamines 9,9′-bis (4-aminophenyl) fluorene (FDA) and 4,4′-diaminobenzanilide (DABA). The optical transparency, anisotropy and dimension stability of CPI films are initially optimized by adjusting the DABA-to-FDA molar ratios, and later by HMPDA-to-CpODA ratios. T_g trend analysis, d-spacing calculated from WAXD patterns, and the FTIR wavenumber shifts of the functional groups implied that the strength of hydrogen bonding is relatively higher in CpODA-based CPIs than the HPMDA systems, which may resulted in improved thermal properties of CPI films. It is shown that the polyimide PI-7-5 film displayed excellent comprehensive properties with an ultra-high T_g of 458 °C, low CTE of 29.0 ppm/K, and also a low R_th of 187 nm. Notably, it has a 90 % transmittance in the visible region, along with robust mechanical properties such as a tensile strength of 111 MPa, and an elastic modulus of 3.8 GPa, and good film folding reliability against extensive folding/unfolding cycles, making it an excellent choice for flexible TFT-LCD substrate.

传统的无色聚酰亚胺（CPI）薄膜通常具有高热膨胀系数（CTE）、高光阻（Rth）或低玻璃化转变温度（Tg）值。然而，在柔性显示应用中，尤其是柔性薄膜晶体管液晶显示器（TFT-LCD）基板中，如何在低 Rth 和低 CTE 之间取得平衡，同时又不牺牲 CPI 薄膜的高 Tg 值，仍然是一项挑战。由脂环族二酐氢化吡咯烷二酐（HPMDA）和环戊酮双铁硼烷四羧酸二酐（CpODA）与芳香族二胺 9,9'-双（4-氨基苯基）芴（FDA）和 4,4'-二氨基苯甲酰苯胺（DABA）共聚制备了一组无色聚酰亚胺薄膜。最初是通过调整 DABA 与 FDA 的摩尔比来优化 CPI 薄膜的光学透明度、各向异性和尺寸稳定性，后来又通过调整 HMPDA 与 CpODA 的摩尔比来优化 CPI 薄膜的光学透明度、各向异性和尺寸稳定性。Tg 趋势分析、WAXD 图谱计算出的 d 间距以及官能团的傅立叶变换红外波长移动表明，与 HPMDA 系统相比，CpODA 基 CPI 的氢键强度相对较高，这可能会改善 CPI 薄膜的热性能。研究表明，聚酰亚胺 PI-7-5 薄膜具有优异的综合性能，其超高 Tg 为 458 ℃，低 CTE 为 29.0 ppm/K，低 Rth 为 187 nm。值得注意的是，它在可见光区域的透射率高达 90%，同时还具有强大的机械性能，如 111 兆帕的拉伸强度和 3.8 GPa 的弹性模量，以及良好的薄膜折叠可靠性，可承受大量的折叠/展开循环，因此是柔性 TFT-LCD 衬底的绝佳选择。

{"title":"Ultra-high Tg colorless polyimide film with balanced optical retardation and coefficient of thermal expansion for flexible display","authors":"Nafeesa Mushtaq, Yujie Zhang, Maria Nazir, Liyun Tan, Guofei Chen, Xingzhong Fang","doi":"10.1016/j.polymer.2025.128085","DOIUrl":"10.1016/j.polymer.2025.128085","url":null,"abstract":"<div><div>Traditional colorless polyimide (CPI) films often have high coefficient of thermal expansion (CTE), high optical retardation (R<sub>th</sub>) or low glass transition temperature (<em>T</em><sub>g</sub>) values. However, it remains challengeable to establish a balance between low R<sub>th</sub> and low CTE without sacrificing the high <em>T</em><sub>g</sub> of CPI film for flexible display applications, especially for flexible thin-film-transistor liquid-crystal display (TFT-LCD) substrate. A set of colorless polyimides films are prepared from copolymerization of alicyclic dianhydrides hydrogenated pyromellitic dianhydride (HPMDA) and cyclopentanone bis-spironorbornane tetracarboxylic dianhydride (CpODA) with aromatic diamines 9,9′-bis (4-aminophenyl) fluorene (FDA) and 4,4′-diaminobenzanilide (DABA). The optical transparency, anisotropy and dimension stability of CPI films are initially optimized by adjusting the DABA-to-FDA molar ratios, and later by HMPDA-to-CpODA ratios. <em>T</em><sub>g</sub> trend analysis, <em>d</em>-spacing calculated from WAXD patterns, and the FTIR wavenumber shifts of the functional groups implied that the strength of hydrogen bonding is relatively higher in CpODA-based CPIs than the HPMDA systems, which may resulted in improved thermal properties of CPI films. It is shown that the polyimide PI-7-5 film displayed excellent comprehensive properties with an ultra-high <em>T</em><sub>g</sub> of 458 °C, low CTE of 29.0 ppm/K, and also a low R<sub>th</sub> of 187 nm. Notably, it has a 90 % transmittance in the visible region, along with robust mechanical properties such as a tensile strength of 111 MPa, and an elastic modulus of 3.8 GPa, and good film folding reliability against extensive folding/unfolding cycles, making it an excellent choice for flexible TFT-LCD substrate.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"321 ","pages":"Article 128085"},"PeriodicalIF":4.1,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035113","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}

引用次数: 0

AM/AMPS delignified wood-based hydrogel with enhanced mechanical strength and fatigue resistance for wearable strain sensing and energy harvesting

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-01-25 DOI: 10.1016/j.polymer.2025.128075

Yanyang He , Jiuming Xiong , Yufang Hu , Zhiyong Guo , Sui Wang , Jie Mao

Hydrogels with enhanced mechanical strength and fatigue resistance have attracted considerable attention in the development of advanced triboelectric nanogenerators (TENGs). Flexible electrode is the key to the preparation of TENG. However, the preparation process of traditional flexible electrode is complex, the mechanical strength is poor, and the cost is high. These factors limit its application and development. In this work, a composite material named AM/AMPS wood-based hydrogel (AWH) was reported, which was composed of acrylamide (AM)/2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) hydrogel and delignification wood. AWH combines the natural fiber structure of wood and the softness of hydrogel, and has excellent mechanical properties and fatigue resistance. AWH is assembled into a triboelectric nanogenerator (AWH-TENG), which has high power generation performance and low cost. The AWH-TENG has an open circuit voltage of 60 V and can light up 113 LED bulbs. At the same time, AWH is sensitive to mechanical stimuli, so we have carried out research on its application in the field of wearable motion monitoring and writing sensing and achieved good results. In addition, the writing sensing system based on AWH-TENG is expected to be combined with deep learning to develop a new handwriting recognition system.

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引用次数: 0

Mass-produce sub-15 nm polymeric soft-nanoparticles and cold-flow conditions

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-01-23 DOI: 10.1016/j.polymer.2025.128082

Chunhua Li, Yifu Ruan, GengXin Liu

Polymeric soft-nanoparticles (SNPs) synthesized via microemulsion polymerization, are widely used in both academia and industry. However, achieving a significantly smaller diameter still presents a challenge. Despite the use of excess surfactants, surface tension constraints prevent microemulsion droplets from decreasing in diameter below 20 nm. Still using conventional surfactants, we introduce a simple and efficient method for mass production of SNPs down to 10–15 nm in diameter. The microemulsion is prepared by incorporating solvents that are good for both monomers and polymers. This method effectively yields significantly smaller SNPs. In the melts of such small SNPs, the Rouse-like viscous-dominant behavior is observed and fully mapped with respect to the diameter and degree of cross-linking. This was previously not observed in microemulsion polymerized SNPs. We assess the cold flow conditions by determining the ability to form transparent sheets from the powder at room temperature when subjected to pressure. It is governed by the diameter and degree of crosslinking. The ultrasmall SNPs thus have the potential to be used as fillers in various industries.

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引用次数: 0

Impact of uniaxial strain programming on morphology and electrical properties of PET from amorphous precursors

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer

Pub Date : 2025-01-23 DOI: 10.1016/j.polymer.2025.128078

Jiahao Mao , Jierui Zhou , Yang Cao , Mukerrem Cakmak

This study examines the morphological evolution of melt-cast Poly (ethylene terephthalate) (PET) thin films under nonlinear deformation strategies, specifically stretching and cycling, to analyze their structural, mechanical, and electrical properties. Capacitor-grade thin films were melt-cast and subjected to uniaxial deformation using an instrumented stretching machine that applied programmable deformations. During deformation, real-time mechano-optical data, including birefringence, true strain, and true stress, were collected above the glass transition temperature (Tg).

Stress-induced crystallization emerged as the primary mechanism during stretching, as thermally induced crystallization was suppressed due to high viscosity in the rubbery temperatures near Tg. Strain oscillations after steady deformations at various strain levels promoted crystallization and relaxed oriented amorphous chains. This process enhanced crystalline orientation and crystallinity, particularly in stretching and oscillation tests compared to stretching and holding tests. At higher deformation levels, the orientation of amorphous domains transitioned to oriented crystalline structures. Increased crystallinity and crystalline and amorphous chain orientation enhanced electrical breakdown. The strain oscillation played a crucial role in promoting crystallinity enhancement while minimizing amorphous chain orientation, leading to lower electrical breakdown. These results highlight the substantial influence of the amorphous phase and its chain orientation on the electrical breakdown of PET films.

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引用次数: 0