Large-scale applications of versatile cellulose cryogels have received much concern but remains challenging due to their complicated post-treatment and brittleness nature. A organic solvent-free and mechanical-assisted strategy was proposed here to effectively exfoliate cellulose microfibrils. The flexible, ultralight, elastic, and multi-scale cellulose hybrid cryogels were manufactured by adding tiny dosage of polyamide-epichlorohydrin (PAE), which was employed here as flexible and crosslinked skeleton. Undergoing freeze drying and vacuum heating, a series of CMFs/PAEx cryogels were successfully acquired with superior mechanical and thermal insulation performances. CMFs/PAE0.5 cryogel achieved 2.5 folds stress at 80% compressive strain and 2.4 folds elastic recovery with respect to CMFs/PAE0. The hydrophobic modification of the CMFs/PAEx cryogels were readily accessible by dip-coating of palm wax and endowed these cryogels with good water repellency (contact angle of ∼128o). Overall, the proposed strategy open up novel perspectives for the design of cellulose cryogels and beyond.
{"title":"Scalable manufacturing of cellulose microfibril cryogel without organic solvent by adding tiny dosage of polyamide-epichlorohydrin","authors":"Wentao Wang, Rui Zhang, Jing Bai, Jing Peng, Wu Mang","doi":"10.1016/j.polymer.2025.128050","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128050","url":null,"abstract":"Large-scale applications of versatile cellulose cryogels have received much concern but remains challenging due to their complicated post-treatment and brittleness nature. A organic solvent-free and mechanical-assisted strategy was proposed here to effectively exfoliate cellulose microfibrils. The flexible, ultralight, elastic, and multi-scale cellulose hybrid cryogels were manufactured by adding tiny dosage of polyamide-epichlorohydrin (PAE), which was employed here as flexible and crosslinked skeleton. Undergoing freeze drying and vacuum heating, a series of CMFs/PAEx cryogels were successfully acquired with superior mechanical and thermal insulation performances. CMFs/PAE0.5 cryogel achieved 2.5 folds stress at 80% compressive strain and 2.4 folds elastic recovery with respect to CMFs/PAE0. The hydrophobic modification of the CMFs/PAEx cryogels were readily accessible by dip-coating of palm wax and endowed these cryogels with good water repellency (contact angle of ∼128<sup>o</sup>). Overall, the proposed strategy open up novel perspectives for the design of cellulose cryogels and beyond.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"16 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142961736","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}
{"title":"Corrigendum to “Improvement of dielectric, processing and mechanical properties of phthalonitrile resins by copolymerisation with bismaleimide resin” [Polymer 317 (2025) 127962]","authors":"Jiajia Ye, Tao Wang, Miao Wu, Shuai Zhang, Xiaobo Liu, Lifen Tong","doi":"10.1016/j.polymer.2024.128013","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.128013","url":null,"abstract":"The authors regret.<span><span><span><p><span>Table 3</span>. Principal data about TMA test.</p></span></span><table><thead><tr><th scope=\"col\">Sample</th><th scope=\"col\">T<sub>g1</sub> (°C)</th><th scope=\"col\">T<sub>g2</sub> (°C)</th><th scope=\"col\">CTE (ppm/<sup>o</sup>C)</th></tr></thead><tbody><tr><td>Poly(PN)</td><td>153</td><td>245</td><td>134</td></tr><tr><td>Poly(PN-10BDM)</td><td>155</td><td>237</td><td>115</td></tr><tr><td>Poly(PN-20BDM)</td><td>159</td><td>235</td><td>99.2</td></tr><tr><td>Poly(PN-30BDM)</td><td>159</td><td>240</td><td>96.1</td></tr><tr><td>Poly(PN-40BDM)</td><td>163</td><td>246</td><td>94.1</td></tr></tbody></table></span>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"85 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940465","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}
Poly(vinylidene fluoride) (PVDF) with the best piezoelectric property among polymers has great potential applications in many fields. The low performance with a |d33| < 30 pC/N limits, however, its application. Therefore, it is of great significance and importance to improve its piezoelectric property. We have realized the creation of order-to-disorder-to-order transition regions through partial γ-β solid-phase transition via electric poling, which endows the PVDF film a morphotropic phase boundary like behavior and thus enhances the piezoelectricity of PVDF tremendously. As a result, an ultrahigh piezoelectric coefficient of |d33| = 69.9 pm/V has been achieved, which is to our best knowledge the state-of-the-art largest |d33| for randomly oriented PVDF homopolymer films. This paves a simple way for fabricating high performance piezoelectric PVDF homopolymers.
{"title":"Ultrahigh piezoelectric coefficient of poly(vinylidene fluoride) achieved via electric-poling-induced partial γ-β phase transition","authors":"Hanqi Zhu, Haipeng Li, Haoying Song, Jiameng Liang, Wenpeng Zhao, Shaojuan Wang, Jian Hu, Rui Xin, Hao Zhang, Xiaoli Sun, Shouke Yan","doi":"10.1016/j.polymer.2025.128045","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128045","url":null,"abstract":"Poly(vinylidene fluoride) (PVDF) with the best piezoelectric property among polymers has great potential applications in many fields. The low performance with a |d<sub>33</sub>| < 30 pC/N limits, however, its application. Therefore, it is of great significance and importance to improve its piezoelectric property. We have realized the creation of order-to-disorder-to-order transition regions through partial γ-β solid-phase transition <em>via</em> electric poling, which endows the PVDF film a morphotropic phase boundary like behavior and thus enhances the piezoelectricity of PVDF tremendously. As a result, an ultrahigh piezoelectric coefficient of |d<sub>33</sub>| = 69.9 pm/V has been achieved, which is to our best knowledge the state-of-the-art largest |d<sub>33</sub>| for randomly oriented PVDF homopolymer films. This paves a simple way for fabricating high performance piezoelectric PVDF homopolymers.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"1 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937164","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}
In this article, the hyperelastic material of resilient wheels of subway vehicles is taken as the research object, a method system of identifying and calibrating the constitutive parameters of hyperelastic model based on joint experiment-simulation-deep learning is proposed. The theoretical analytical expression of the true stress-strain on stretch of the hyperelastic model Yeoh model under uniaxial loading condition is deduced, the accurate stress-strain curve data are captured by performing the compression experiment of cylindrical specimen of rubber component of urban rail transit system resilient wheel, and the initial values of parameters of the Yeoh hyperelastic model are fitted by the experimental data. The true stress-strain response samples of compression specimens under different Yeoh model parameter conditions were obtained by finite element numerical simulation. The Yeoh model's optimal parameters are obtained by training the data using a deep learning technique under the specified compression test stress-strain circumstances. Finite element numerical simulation is utilized to confirm the parameters' accuracy. The radial stiffness test of the resilient wheel rubber component was carried out, and the examination of the resilient wheel rubber component's stiffness analysis using the model parameters that were optimized. The study's findings indicate that the methodological system of identifying and calibrating the hyperelastic model constitutive parameters of the hyperelastic model proposed in this paper by combined experiment-simulation-deep learning has high prediction accuracy for the hyperelastic constitutive model parameters.
{"title":"Deep learning-based calibration method for material parameters of resilient wheel rubber components","authors":"Qiang Zhang, Zhiming Liu, Guangxue Yang, Yang Jing, Yiliang Shu, Sixi Zha","doi":"10.1016/j.polymer.2025.128044","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128044","url":null,"abstract":"In this article, the hyperelastic material of resilient wheels of subway vehicles is taken as the research object, a method system of identifying and calibrating the constitutive parameters of hyperelastic model based on joint experiment-simulation-deep learning is proposed. The theoretical analytical expression of the true stress-strain on stretch of the hyperelastic model Yeoh model under uniaxial loading condition is deduced, the accurate stress-strain curve data are captured by performing the compression experiment of cylindrical specimen of rubber component of urban rail transit system resilient wheel, and the initial values of parameters of the Yeoh hyperelastic model are fitted by the experimental data. The true stress-strain response samples of compression specimens under different Yeoh model parameter conditions were obtained by finite element numerical simulation. The Yeoh model's optimal parameters are obtained by training the data using a deep learning technique under the specified compression test stress-strain circumstances. Finite element numerical simulation is utilized to confirm the parameters' accuracy. The radial stiffness test of the resilient wheel rubber component was carried out, and the examination of the resilient wheel rubber component's stiffness analysis using the model parameters that were optimized. The study's findings indicate that the methodological system of identifying and calibrating the hyperelastic model constitutive parameters of the hyperelastic model proposed in this paper by combined experiment-simulation-deep learning has high prediction accuracy for the hyperelastic constitutive model parameters.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"31 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937660","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 : 2025-01-09DOI: 10.1016/j.polymer.2025.128046
Yan Yan, Qun-Liang Zhang, Youhua Tao
A series of copolymers featuring polyamide-6 skeleton were synthesized through the ring-opening copolymerization of seven membered cyclic lactam monomers derived from lysine with varying degrees of hydrophilicity. Dimethyl protected cyclic lysine (DMCL) serves as a certainly hydrophilic comonomer, while the hydrophobic comonomer bears longer substitutive alkyl groups on the side nitrogen atom, such as dibutyl protected cyclic lysine (DBCL). Both calculations and experimental results indicate the resulted copolymers possess random structures. Nevertheless, amphiphilic copolymers can be achieved by reasonably adjusting the length of the alkyl chain in the hydrophobic monomer and flexibly varying the ratio of hydrophilic and hydrophobic units. Notably, poly(DMCL-co-DBCL)73, which has a hydrophilic to hydrophobic ratio of 7 to 3, is capable of self-assembling into well-defined micelles in water and showed excellent potential for drug delivery applications.
{"title":"Synthesis of lysine-based amphiphilic random copolymers capable of self-assembly in water","authors":"Yan Yan, Qun-Liang Zhang, Youhua Tao","doi":"10.1016/j.polymer.2025.128046","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128046","url":null,"abstract":"A series of copolymers featuring polyamide-6 skeleton were synthesized through the ring-opening copolymerization of seven membered cyclic lactam monomers derived from lysine with varying degrees of hydrophilicity. Dimethyl protected cyclic lysine (DMCL) serves as a certainly hydrophilic comonomer, while the hydrophobic comonomer bears longer substitutive alkyl groups on the side nitrogen atom, such as dibutyl protected cyclic lysine (DBCL). Both calculations and experimental results indicate the resulted copolymers possess random structures. Nevertheless, amphiphilic copolymers can be achieved by reasonably adjusting the length of the alkyl chain in the hydrophobic monomer and flexibly varying the ratio of hydrophilic and hydrophobic units. Notably, poly(DMCL-co-DBCL)73, which has a hydrophilic to hydrophobic ratio of 7 to 3, is capable of self-assembling into well-defined micelles in water and showed excellent potential for drug delivery applications.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"118 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937170","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 : 2025-01-08DOI: 10.1016/j.polymer.2025.128039
Dikla Kolan, Susan Kozawa, Dmitrii Weitzer, Gary Wnek, Matan Mussel
The competition between mono- and divalent counterions in polyelectrolyte gels can lead to reversible transitions between swollen and collapsed phases. In this study, we investigate the emergence of a propagating boundary that separates the two phases in cylindrical polyacrylate gels, where it moves along the gel's longitudinal axis. We emphasize the distinction between an overall calcium-induced contraction and the axial progression phenomenon and use an object detection algorithm to determine the boundary propagation rate. Additionally, we investigate how calcium concentration, external voltage, and gel diameter influence the formation time and propagation velocity of the phase boundary. Our findings reveal that an increased calcium concentration in the adjacent bath, the application of an external voltage, and a decreased gel diameter contribute to a shorter formation time and a higher propagation velocity of the phase boundary. These results provide important insights into the complex dynamics of phase boundaries in cylindrical polyelectrolyte gels.
{"title":"Propagation of a Chemo-Mechanical Phase Boundary in Polyacrylate Gels","authors":"Dikla Kolan, Susan Kozawa, Dmitrii Weitzer, Gary Wnek, Matan Mussel","doi":"10.1016/j.polymer.2025.128039","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128039","url":null,"abstract":"The competition between mono- and divalent counterions in polyelectrolyte gels can lead to reversible transitions between swollen and collapsed phases. In this study, we investigate the emergence of a propagating boundary that separates the two phases in cylindrical polyacrylate gels, where it moves along the gel's longitudinal axis. We emphasize the distinction between an overall calcium-induced contraction and the axial progression phenomenon and use an object detection algorithm to determine the boundary propagation rate. Additionally, we investigate how calcium concentration, external voltage, and gel diameter influence the formation time and propagation velocity of the phase boundary. Our findings reveal that an increased calcium concentration in the adjacent bath, the application of an external voltage, and a decreased gel diameter contribute to a shorter formation time and a higher propagation velocity of the phase boundary. These results provide important insights into the complex dynamics of phase boundaries in cylindrical polyelectrolyte gels.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"14 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937165","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 : 2025-01-08DOI: 10.1016/j.polymer.2025.128040
Odda Ruiz de Ballesteros, Andrea Rispo, Giuseppe Femina, Simone Davide, Francesca Nocella, Roberta Romano, Roberta Cipullo, Finizia Auriemma
The role of entanglements and co-crystallization in the compatibilization of iPP/PE blends with PP-based diblock copolymers (BCs) was investigated. A smart design of experiments was set up, based on the selection of two different BCs, iPP/HDPE and iPP/LDPE blends (30/70 wt%/wt%), and different processing conditions. The selected BCs were a hard-hard copolymer with crystalline iPP and PE blocks (BC1), and a hard-soft copolymer with iPP blocks linked to amorphous EP blocks (BC2). Both BCs significantly improved blend morphology by inducing a fine dispersion of the minority iPP phase in the PE matrix, even at low loads (3–5 wt%). However, they exert different compatibilization effectiveness. In iPP/HDPE blends, trapped entanglements are coupled with well-formed co-crystals of large lamellar thickness, and only 3 wt% of BC1 is sufficient to ensure good ductility and toughness. For iPP/LDPE blends, larger BC1 content (over 5 wt%) was needed due to formation of thinner co-crystals. In contrast, BC2, which does not co-crystallize with PE, only ensures good adhesion in rapidly cooled samples due to the “freezing” of trapped entanglements.
{"title":"Compatibilization of Isotactic Polypropylene (iPP) and Polyethylene (PE) with PP-based Olefin Block Copolymers","authors":"Odda Ruiz de Ballesteros, Andrea Rispo, Giuseppe Femina, Simone Davide, Francesca Nocella, Roberta Romano, Roberta Cipullo, Finizia Auriemma","doi":"10.1016/j.polymer.2025.128040","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128040","url":null,"abstract":"The role of entanglements and co-crystallization in the compatibilization of iPP/PE blends with PP-based diblock copolymers (BCs) was investigated. A smart design of experiments was set up, based on the selection of two different BCs, iPP/HDPE and iPP/LDPE blends (30/70 wt%/wt%), and different processing conditions. The selected BCs were a hard-hard copolymer with crystalline iPP and PE blocks (BC1), and a hard-soft copolymer with iPP blocks linked to amorphous EP blocks (BC2). Both BCs significantly improved blend morphology by inducing a fine dispersion of the minority iPP phase in the PE matrix, even at low loads (3–5 wt%). However, they exert different compatibilization effectiveness. In iPP/HDPE blends, trapped entanglements are coupled with well-formed co-crystals of large lamellar thickness, and only 3 wt% of BC1 is sufficient to ensure good ductility and toughness. For iPP/LDPE blends, larger BC1 content (over 5 wt%) was needed due to formation of thinner co-crystals. In contrast, BC2, which does not co-crystallize with PE, only ensures good adhesion in rapidly cooled samples due to the “freezing” of trapped entanglements.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"35 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936129","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}
A series of novel 4,4-bisubstituted ε-caprolactone (CL) monomers with pendent aryl and cyano groups were designed and effectively synthesized from commercially available aryl nitriles with methyl acrylate. The synthetic process relies on a tandem double Michael addition-Dieckmann condensation-Krapcho decarboxylation in a one-pot system, followed by a subsequent Baeyer-Villiger oxidation. Furthermore, the ring-opening polymerization of these obtained CL monomers was successfully achieved under mild reaction conditions, employing p-methylbenzyl alcohol as the initiator and 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) as an organocatalyst. The glass transition temperatures (Tg) of the resultant polyesters were in the range of 45 to 95 °C, strongly dependent on the cyano and aryl substituents. More importantly, the resultant polyesters could be effectively depolymerized in alkali condition to generate the corresponding ε-hydroxy caproic acids with excellent yields, which could be transformed back to their starting monomers via subsequent lactonization process, thus establishing their circular life cycle.
{"title":"Synthesis and Ring-Opening Polymerization of Bisubstituted ε-Caprolactones Bearing Aryl and Cyano Groups","authors":"Peng-Fei Gao, Hong-Ran Wang, Xiang-Xi Xiao, Wei-Min Ren, Xiao-Bing Lu, Hui Zhou","doi":"10.1016/j.polymer.2025.128034","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128034","url":null,"abstract":"A series of novel 4,4-bisubstituted <em>ε</em>-caprolactone (CL) monomers with pendent aryl and cyano groups were designed and effectively synthesized from commercially available aryl nitriles with methyl acrylate. The synthetic process relies on a tandem double Michael addition-Dieckmann condensation-Krapcho decarboxylation in a one-pot system, followed by a subsequent Baeyer-Villiger oxidation. Furthermore, the ring-opening polymerization of these obtained CL monomers was successfully achieved under mild reaction conditions, employing <em>p</em>-methylbenzyl alcohol as the initiator and 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) as an organocatalyst. The glass transition temperatures (<em>T</em><sub><em>g</em></sub>) of the resultant polyesters were in the range of 45 to 95 °C, strongly dependent on the cyano and aryl substituents. More importantly, the resultant polyesters could be effectively depolymerized in alkali condition to generate the corresponding <em>ε</em>-hydroxy caproic acids with excellent yields, which could be transformed back to their starting monomers <em>via</em> subsequent lactonization process, thus establishing their circular life cycle.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"23 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936143","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 : 2025-01-07DOI: 10.1016/j.polymer.2025.128042
Yu Chen, Ning Wang, Di Zhang, Zhiyang Tian, Xin Lu, Pei Li, Muhammad Qasim, Fuzhou Wang
To develop a new polyolefin thermoplastic elastomer, it is crucial to focus on enhancing the impact modification of polypropylene. In this contribution, the successful synthesis of polyethylene thermoplastic elastomers with great mechanical and elastic properties via chain-walking ethylene polymerization using bulky α-diimine nickel catalysts bearing both the t-butylated dibenzhydryl and the p-substituted phenyl moieties. These bulky groups providing greater solubility and steric hindrance also led to great thermal stability and high activities of up to 1.1 × 107 g·PE·mol·Ni–1·h–1, generating high molecular weight polyethylene with moderately branched microstructures (64–87 branches/1000 C). The branched polyethylene exhibited thermoplastic elastomer characteristics and demonstrated excellent elastic recovery properties up to 78%–85% by Ni2 and Ni3 respectively which is higher compared to Ni1 (SR % = 67%). Most importantly, the impact properties of polypropylene can be enhanced through the incorporation of a polyethylene elastomer blend, resulting in superior performance.
{"title":"Preparation of polyethylene elastomers via controlled chain-walking ethylene polymerization for enhanced impact modification of polypropylene","authors":"Yu Chen, Ning Wang, Di Zhang, Zhiyang Tian, Xin Lu, Pei Li, Muhammad Qasim, Fuzhou Wang","doi":"10.1016/j.polymer.2025.128042","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128042","url":null,"abstract":"To develop a new polyolefin thermoplastic elastomer, it is crucial to focus on enhancing the impact modification of polypropylene. In this contribution, the successful synthesis of polyethylene thermoplastic elastomers with great mechanical and elastic properties via chain-walking ethylene polymerization using bulky <em>α</em>-diimine nickel catalysts bearing both the <em>t</em>-butylated dibenzhydryl and the <em>p</em>-substituted phenyl moieties. These bulky groups providing greater solubility and steric hindrance also led to great thermal stability and high activities of up to 1.1 × 10<sup>7</sup> g·PE·mol·Ni<sup>–1</sup>·h<sup>–1</sup>, generating high molecular weight polyethylene with moderately branched microstructures (64–87 branches/1000 C). The branched polyethylene exhibited thermoplastic elastomer characteristics and demonstrated excellent elastic recovery properties up to 78%–85% by <strong>Ni2</strong> and <strong>Ni3</strong> respectively which is higher compared to <strong>Ni1</strong> (SR % = 67%). Most importantly, the impact properties of polypropylene can be enhanced through the incorporation of a polyethylene elastomer blend, resulting in superior performance.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"46 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936131","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}
Aromatic polyimide (PI) is widely used in aerospace, microelectronics, and transformer insulation due to its excellent performance and design flexibility. With the rapid development of the military industry, the insulation layer of Tesla transformer windings demands low dielectric, high heat resistance, high breakdown strength, and aging resistance. This paper studies the performance of polyimide insulation film based on theoretical calculation and experimental methods. We used molecular simulation technology and density functional theory (DFT) to study the microscopic electrical and optical properties of polyimide molecules with eight structures, which saved time for subsequent experimental design. Then, we studied ordinary polyimide film, fluorinated polyimide film, and polyimide film with mica filler using experimental methods. We also analyzed the dielectric, electrical, and ageing properties of polyimide composites and finally prepared polyimide composites with excellent comprehensive performance.
{"title":"Molecular Simulation and Experimental Investigation of Enhanced Thermal and Dielectric Properties in Mica-Filled Polyimide Films","authors":"Zhongli Zhang, Zhensheng Wu, Shuai Zheng, Haitao Yang, Fuqiang Tian","doi":"10.1016/j.polymer.2025.128043","DOIUrl":"https://doi.org/10.1016/j.polymer.2025.128043","url":null,"abstract":"Aromatic polyimide (PI) is widely used in aerospace, microelectronics, and transformer insulation due to its excellent performance and design flexibility. With the rapid development of the military industry, the insulation layer of Tesla transformer windings demands low dielectric, high heat resistance, high breakdown strength, and aging resistance. This paper studies the performance of polyimide insulation film based on theoretical calculation and experimental methods. We used molecular simulation technology and density functional theory (DFT) to study the microscopic electrical and optical properties of polyimide molecules with eight structures, which saved time for subsequent experimental design. Then, we studied ordinary polyimide film, fluorinated polyimide film, and polyimide film with mica filler using experimental methods. We also analyzed the dielectric, electrical, and ageing properties of polyimide composites and finally prepared polyimide composites with excellent comprehensive performance.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"100 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936128","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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