Pub Date : 2025-01-30DOI: 10.1016/j.polymer.2025.128107
Glendimar Molero , Sumit Khatri , Jarian Galloway , Shuoran Du , Hung-Jue Sue , Peter Vollenberg , Yuntao Li
The scratch behavior of injection-molded model polycarbonate (PC) systems was investigated according to the ASTM scratch test methodology. Four model PC systems with different tensile and compressive yield stresses were investigated to determine what are the governing parameters determining the scratch visibility and scratch cracking resistance. Coefficient of friction (COF) measurements, uniaxial tensile and compressive true stress-strain curves, and dynamic mechanical analyses were conducted to correlate the intrinsic material properties to the observed scratch-induced deformation of the model PC systems. Special attention is given to how the geometric scratch parameters, such as scratch depth and shoulder height, correlate with the mechanical properties and the scratch visibility of the model PC systems. It is found that the tensile yield and compressive yield stresses and surface characteristics and the COF dominate the scratch deformation process, thus the scratch performance of PC.
{"title":"Effect of tensile and compressive properties on the scratch behavior of injection-molded polycarbonate model systems","authors":"Glendimar Molero , Sumit Khatri , Jarian Galloway , Shuoran Du , Hung-Jue Sue , Peter Vollenberg , Yuntao Li","doi":"10.1016/j.polymer.2025.128107","DOIUrl":"10.1016/j.polymer.2025.128107","url":null,"abstract":"<div><div>The scratch behavior of injection-molded model polycarbonate (PC) systems was investigated according to the ASTM scratch test methodology. Four model PC systems with different tensile and compressive yield stresses were investigated to determine what are the governing parameters determining the scratch visibility and scratch cracking resistance. Coefficient of friction (COF) measurements, uniaxial tensile and compressive true stress-strain curves, and dynamic mechanical analyses were conducted to correlate the intrinsic material properties to the observed scratch-induced deformation of the model PC systems. Special attention is given to how the geometric scratch parameters, such as scratch depth and shoulder height, correlate with the mechanical properties and the scratch visibility of the model PC systems. It is found that the tensile yield and compressive yield stresses and surface characteristics and the COF dominate the scratch deformation process, thus the scratch performance of PC.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128107"},"PeriodicalIF":4.1,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071980","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 : 2025-01-30DOI: 10.1016/j.polymer.2025.128105
Gianni Pecorini , Dario Puppi , Stephen M. Richardson , Guo-Qiang Chen , Marco A.N. Domingos
Three-dimensional (3D) scaffolds are a critical component in guided-tissue regeneration strategies, particularly in cartilage engineering, by providing an adequate structural and physical environment for seeded cells to proliferate and eventually differentiate. Here we investigate the use of microbial poly(3-hydroxybutyrate-co-3-hydroxyexanoate) (PHBHHx) as polymeric inks for 3D printing of scaffolds and weigh their chondrogenic potential against commonly used poly(ε-caprolactone) (PCL). A set of processing parameters is first optimized for extrusion-based printing of porous PHBHHx and PCL scaffolds with well-defined architectures and without affecting the polymer's physicochemical properties. Mechanical testing results obtained under static compression confirm the fabrication of PHBHHx scaffolds with elastic modulus values comparable to those of human mature cartilage. LIVE/DEAD™ and AlamarBlue assays do not reveal any cytotoxic effect of PHBHHx scaffolds on primary human chondrocytes, which remain viable over 14 days of in vitro static culture. Additionally, real-time RT-qPCR analysis of key chondrogenic markers (i.e., SOX9, COL2A1 and ACAN) suggests chondrocytes retain their phenotype over the studied period, independently of the scaffolding material. Taken together, our results confirm the suitability of PHBHHx scaffolds to support the function of chondrocytes in vitro, opening new opportunities for their application in the field of cartilage tissue engineering.
{"title":"3D printed poly(3-hydroxybutyrate-co-3-hydroxyexanoate) scaffolds support chondrogenic potential of human primary chondrocytes during in vitro culture","authors":"Gianni Pecorini , Dario Puppi , Stephen M. Richardson , Guo-Qiang Chen , Marco A.N. Domingos","doi":"10.1016/j.polymer.2025.128105","DOIUrl":"10.1016/j.polymer.2025.128105","url":null,"abstract":"<div><div>Three-dimensional (3D) scaffolds are a critical component in guided-tissue regeneration strategies, particularly in cartilage engineering, by providing an adequate structural and physical environment for seeded cells to proliferate and eventually differentiate. Here we investigate the use of microbial poly(3-hydroxybutyrate-<em>co</em>-3-hydroxyexanoate) (PHBHHx) as polymeric inks for 3D printing of scaffolds and weigh their chondrogenic potential against commonly used poly(ε-caprolactone) (PCL). A set of processing parameters is first optimized for extrusion-based printing of porous PHBHHx and PCL scaffolds with well-defined architectures and without affecting the polymer's physicochemical properties. Mechanical testing results obtained under static compression confirm the fabrication of PHBHHx scaffolds with elastic modulus values comparable to those of human mature cartilage. LIVE/DEAD™ and AlamarBlue assays do not reveal any cytotoxic effect of PHBHHx scaffolds on primary human chondrocytes, which remain viable over 14 days of <em>in vitro</em> static culture. Additionally, real-time RT-qPCR analysis of key chondrogenic markers (i.e., SOX9, COL2A1 and ACAN) suggests chondrocytes retain their phenotype over the studied period, independently of the scaffolding material. Taken together, our results confirm the suitability of PHBHHx scaffolds to support the function of chondrocytes <em>in vitro</em>, opening new opportunities for their application in the field of cartilage tissue engineering.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128105"},"PeriodicalIF":4.1,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071935","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 : 2025-01-29DOI: 10.1016/j.polymer.2025.128095
Chandan Bodhak , Pranabesh Sahu , Ram K. Gupta
Vitrimers have currently emerged as an ideal alternative to conventional thermosetting resins combining the benefits of both thermoplastic and thermoset. But, maintaining the superior performance of vitrimers with good mechanical and stimuli-responsive properties still presents significant challenges. Epoxidized plant oil-derived thermosets are typically constrained by their non-processability and poor mechanical qualities. Henceforth, the development of smart, recyclable, and eco-friendly benevolent thermosets by integrating dynamic covalent bonds into cross-linked polymer networks can resolve the trade-off to overcome these drawbacks. In this work, we demonstrate a one-pot thermally-controlled “thiol-acrylate” coupling between a novel soybean oil acrylate (ESBO_HEA) and dynamic diboronic ester dithiol (DBDT) cross-linker to prepare a self-healable biobased vitrimer employing the green chemistry protocols. The synthesized ESBO_HEA-DBDT vitrimers with covalently cross-linked networks can alter the topologies through the exchange of reversible bonds of boronic ester, which allows room temperature self-healing phenomenon. Thermomechanical characteristics and vitrimeric features have been studied by dynamic mechanical analysis, showing that stress relaxes very quickly at low temperatures, leveraging the dioxaborolane exchange metathesis. The absolute value of glass transition temperature (Tg) determined from DMA analysis was 5.22 °C, above which the vitrimer exhibits dynamic nature by associative boronic ester exchange. Moreover, the developed vitrimer demonstrates extensive elongation (700–1200 %) properties and excellent reprocessability. Even after 2 cycles of reprocessing, the mechanical characteristics of the reprocessed vitrimers were retained as compared to the original materials. The self-healing efficiency of the biobased vitrimers reached 100 % at room temperature in less than 15 h, whereas the sample achieved complete healing within 4 h when thermally triggered at 50 °C. Through dynamic-mechanical analyses, ESBO_HEA vitrimer reveals remarkably short relaxation time of 15.6 s at 25 °C and an activation energy of 8.70 kJ/mol. In addition, it can be easily recycled by reversibly hydrolyzing in 95 % ethanol and then evaporating the solvent to regenerate the original vitrimer. Briefly, the present research illustrates the potent malleability, reprocessability, self-healing, and extensive elongation properties of the covalently cross-linked vitrimers derived exclusively from renewable resources.
{"title":"Sustainable soybean oil acrylate for boronic ester vitrimer: Self-healing, reprocessable and extensive elongation performance","authors":"Chandan Bodhak , Pranabesh Sahu , Ram K. Gupta","doi":"10.1016/j.polymer.2025.128095","DOIUrl":"10.1016/j.polymer.2025.128095","url":null,"abstract":"<div><div>Vitrimers have currently emerged as an ideal alternative to conventional thermosetting resins combining the benefits of both thermoplastic and thermoset. But, maintaining the superior performance of vitrimers with good mechanical and stimuli-responsive properties still presents significant challenges. Epoxidized plant oil-derived thermosets are typically constrained by their non-processability and poor mechanical qualities. Henceforth, the development of smart, recyclable, and eco-friendly benevolent thermosets by integrating dynamic covalent bonds into cross-linked polymer networks can resolve the trade-off to overcome these drawbacks. In this work, we demonstrate a one-pot thermally-controlled “<em>thiol-acrylate”</em> coupling between a novel soybean oil acrylate (ESBO_HEA) and dynamic diboronic ester dithiol (DBDT) cross-linker to prepare a self-healable biobased vitrimer employing the green chemistry protocols. The synthesized ESBO_HEA-DBDT vitrimers with covalently cross-linked networks can alter the topologies through the exchange of reversible bonds of boronic ester, which allows room temperature self-healing phenomenon. Thermomechanical characteristics and vitrimeric features have been studied by dynamic mechanical analysis, showing that stress relaxes very quickly at low temperatures, leveraging the dioxaborolane exchange metathesis. The absolute value of glass transition temperature (T<sub>g</sub>) determined from DMA analysis was 5.22 °C, above which the vitrimer exhibits dynamic nature by associative boronic ester exchange. Moreover, the developed vitrimer demonstrates extensive elongation (700–1200 %) properties and excellent reprocessability. Even after 2 cycles of reprocessing, the mechanical characteristics of the reprocessed vitrimers were retained as compared to the original materials. The self-healing efficiency of the biobased vitrimers reached 100 % at room temperature in less than 15 h, whereas the sample achieved complete healing within 4 h when thermally triggered at 50 °C. Through dynamic-mechanical analyses, ESBO_HEA vitrimer reveals remarkably short relaxation time of 15.6 s at 25 °C and an activation energy of 8.70 kJ/mol. In addition, it can be easily recycled by reversibly hydrolyzing in 95 % ethanol and then evaporating the solvent to regenerate the original vitrimer. Briefly, the present research illustrates the potent malleability, reprocessability, self-healing, and extensive elongation properties of the covalently cross-linked vitrimers derived exclusively from renewable resources.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128095"},"PeriodicalIF":4.1,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055263","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 : 2025-01-29DOI: 10.1016/j.polymer.2025.128094
Seonmin Jang, Geunryeol Baek, Minyeong Cheon, Chaeeun Lee, Taehong Kim, Junghyun Sung, Su Chul Yang
The precise regulation of mechanical, chemical, and electrical properties in poly(vinylidene fluoride) PVDF thin films is imperatively required for each specialized application such as chemical and electrical insulators, and ferroelectric energy applications. Thus, extensive research endeavors have been dedicated to the manipulation and control of crystalline phases (specifically α, β, and γ) and overall crystallinity, which are the fundamental determinants of PVDF thin film functionality. In this study, we examined the phase transformation and changes in the degree of crystallinity of PVDF thin films subjected to hot-pressing treatment. The PVDF thin films were initially fabricated using three distinct methods: casting, spin-coating, and electrospinning techniques. Following hot-pressing, the β-phase content generally increased, accompanied by a decrease in the α and γ phases in PVDF thin films. This enhancement is attributed to the stretching and alignment of PVDF macromolecular chains under elevated pressure during the hot-pressing process, which promotes β-phase formation. Additionally, it was elucidated that PVDF thin films with high microscopic porosity prior to hot-pressing exhibited the most significant transformation of α and γ phases to β-phase after hot-pressing. This finding implies that, under high-pressure conditions, the inherent low density of PVDF thin films offers adequate morphology for the stretching of polymer chains. Such structural properties favor the formation of the β-phase crystalline structure.
{"title":"Studies on phase transformations and crystallinity changes of PVDF thin films via hot-pressing treatment","authors":"Seonmin Jang, Geunryeol Baek, Minyeong Cheon, Chaeeun Lee, Taehong Kim, Junghyun Sung, Su Chul Yang","doi":"10.1016/j.polymer.2025.128094","DOIUrl":"10.1016/j.polymer.2025.128094","url":null,"abstract":"<div><div>The precise regulation of mechanical, chemical, and electrical properties in poly(vinylidene fluoride) PVDF thin films is imperatively required for each specialized application such as chemical and electrical insulators, and ferroelectric energy applications. Thus, extensive research endeavors have been dedicated to the manipulation and control of crystalline phases (specifically α, β, and γ) and overall crystallinity, which are the fundamental determinants of PVDF thin film functionality. In this study, we examined the phase transformation and changes in the degree of crystallinity of PVDF thin films subjected to hot-pressing treatment. The PVDF thin films were initially fabricated using three distinct methods: casting, spin-coating, and electrospinning techniques. Following hot-pressing, the β-phase content generally increased, accompanied by a decrease in the α and γ phases in PVDF thin films. This enhancement is attributed to the stretching and alignment of PVDF macromolecular chains under elevated pressure during the hot-pressing process, which promotes β-phase formation. Additionally, it was elucidated that PVDF thin films with high microscopic porosity prior to hot-pressing exhibited the most significant transformation of α and γ phases to β-phase after hot-pressing. This finding implies that, under high-pressure conditions, the inherent low density of PVDF thin films offers adequate morphology for the stretching of polymer chains. Such structural properties favor the formation of the β-phase crystalline structure.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128094"},"PeriodicalIF":4.1,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055400","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}
Electromagnetic pollution and overheating present significant challenges in the development of microelectronic devices. Polyolefins, particularly high-density polyethylene (HDPE), are frequently used polymers in these devices. Therefore, enhancing the electromagnetic shielding efficiency (EMSE) and thermal conductivity of polyolefins is crucial for their performance in such applications. In this article, we synthesized a thermoplastic polyurethane (TPU) composed of 1,5-Naphthalene Diisocyanate (NDI), poly-caprolactone diol (PCL), and 1,4-butanediol (BDO) to regulate the viscoelasticity of high-density polyethylene (HDPE). The findings demonstrate that the graphenization of expanded graphite (EG) and the formation of nanocomposites with TPU-HDPE are achieved during the solid-state shear pan-milling process. This results in the uniform dispersion and high incorporation of 1–3 layers of graphene within the TPU-HDPE matrix. At an EG mass fraction of 50 %, the composite material achieves a thermal conductivity of 6.50 W/m·K, which is 16.25 times higher than that of HDPE. Its electrical conductivity reaches 113.1 S/cm. The EMSE measured as absorption loss (A) and total losses (T), increases as the electromagnetic frequency ranges from 8 GHz to 8.67 GHz. At 8.67 GHz, maximum A and T values of 59.04 dB/mm and 63.08 dB/mm, respectively, are observed.
{"title":"Solid-state shear pan-milling preparation of graphene/TPU-HDPE nanocomposites with thermal conductivity and electromagnetic shielding","authors":"Yichen Zhang, Kanshe Li, Chuangqian Chen, Hongmei Niu, Jie Kang, Jiebing Zhang","doi":"10.1016/j.polymer.2025.128099","DOIUrl":"10.1016/j.polymer.2025.128099","url":null,"abstract":"<div><div>Electromagnetic pollution and overheating present significant challenges in the development of microelectronic devices. Polyolefins, particularly high-density polyethylene (HDPE), are frequently used polymers in these devices. Therefore, enhancing the electromagnetic shielding efficiency (EMSE) and thermal conductivity of polyolefins is crucial for their performance in such applications. In this article, we synthesized a thermoplastic polyurethane (TPU) composed of 1,5-Naphthalene Diisocyanate (NDI), poly-caprolactone diol (PCL), and 1,4-butanediol (BDO) to regulate the viscoelasticity of high-density polyethylene (HDPE). The findings demonstrate that the graphenization of expanded graphite (EG) and the formation of nanocomposites with TPU-HDPE are achieved during the solid-state shear pan-milling process. This results in the uniform dispersion and high incorporation of 1–3 layers of graphene within the TPU-HDPE matrix. At an EG mass fraction of 50 %, the composite material achieves a thermal conductivity of 6.50 W/m·K, which is 16.25 times higher than that of HDPE. Its electrical conductivity reaches 113.1 S/cm. The EMSE measured as absorption loss (<em>A</em>) and total losses (<em>T</em>), increases as the electromagnetic frequency ranges from 8 GHz to 8.67 GHz. At 8.67 GHz, maximum <em>A</em> and <em>T</em> values of 59.04 dB/mm and 63.08 dB/mm, respectively, are observed.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128099"},"PeriodicalIF":4.1,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143056352","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 : 2025-01-28DOI: 10.1016/j.polymer.2025.128098
Youngwon Kong , Hitomi Kawahara , Ryohei Kikuchi , Noboru Ohta , Albert Mufundirwa , Tomoyasu Hirai , Kan Hatakeyama-Sato , Yuta Nabae , Teruaki Hayakawa
Designing appropriate molecular structures is essential for employing the microphase-separated structures of block copolymers in a wide range of applications. This study selected poly(4-vinylpyridine)-block-poly(2,2,2-trifluoroethyl methacrylate) (P4VP-b-PTFEMA) owing to its strong repulsive interactions originating from the fluorine in PTFEMA and its compatibility with additives through P4VP. Thirty distinct P4VP-b-PTFEMA block copolymers with varying compositions were synthesized using reversible addition-fragmentation chain-transfer polymerization. d-spacings of 8.9–59.7 nm were obtained, highlighting the successful preparation of microphase-separated structures with various sizes. Additionally, the introduction of resol as a cross-linking agent, which selectively interacts with P4VP, significantly changed the microphase-separated structures. The findings of this study provide valuable insights into controlling and manipulating block copolymer structures, which has important implications for future applications.
{"title":"Synthesis and characterization of poly(4-vinylpyridine)-block-poly(2,2,2-trifluoroethyl methacrylate) for manipulating periodic nanostructured architectures","authors":"Youngwon Kong , Hitomi Kawahara , Ryohei Kikuchi , Noboru Ohta , Albert Mufundirwa , Tomoyasu Hirai , Kan Hatakeyama-Sato , Yuta Nabae , Teruaki Hayakawa","doi":"10.1016/j.polymer.2025.128098","DOIUrl":"10.1016/j.polymer.2025.128098","url":null,"abstract":"<div><div>Designing appropriate molecular structures is essential for employing the microphase-separated structures of block copolymers in a wide range of applications. This study selected poly(4-vinylpyridine)-<em>block</em>-poly(2,2,2-trifluoroethyl methacrylate) (P4VP-<em>b</em>-PTFEMA) owing to its strong repulsive interactions originating from the fluorine in PTFEMA and its compatibility with additives through P4VP. Thirty distinct P4VP-<em>b</em>-PTFEMA block copolymers with varying compositions were synthesized using reversible addition-fragmentation chain-transfer polymerization. <em>d</em>-spacings of 8.9–59.7 nm were obtained, highlighting the successful preparation of microphase-separated structures with various sizes. Additionally, the introduction of resol as a cross-linking agent, which selectively interacts with P4VP, significantly changed the microphase-separated structures. The findings of this study provide valuable insights into controlling and manipulating block copolymer structures, which has important implications for future applications.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128098"},"PeriodicalIF":4.1,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-28DOI: 10.1016/j.polymer.2025.128093
Yan Zhang, Chenyu Zhou, Zhiquan Pan, Hong Zhou
Optimal epoxy resin materials need to have a combination of excellent properties on flame retardance, smoke suppression, transparency and mechanical strength. However, the current strategy in the design for flame retardants tends to improve flame retardancy, while often accompanied by other performance deterioration. Herein, an ionic compound (A-D) verified with X-ray diffraction technology was synthesized by a simple acid-base neutralization reaction, and applied as a flame retardant agent for EP. EP/A-D thermoset showed good flame retardancy, confirmed by a high limiting oxygen index (LOI) of 36.5 % and a UL-94 V-0 rating when A-D addition was 6 %.The total smoke production (TSP) and total heat release rate (THR) decreased by 65.3 % and 41.9 % when compared with pure EP. The obvious decrease of TSP and THR was contributed to the radical capturing and catalytic charring endowed by A-D. Furthermore, EP/6A-D exhibited outstanding mechanical properties, the tensile strength and flexural strength of EP/6A-D increases by 40.4 % and 150.4 %, respectively, compared to pure EP. Such a strong mechanical strength has hardly been found in the modified EP reported in literatures. Furthermore, the EP composite also has good transparency, and better resistance to corrosion. The excellent overall properties endow EP/6A-D composites great potential for enlarging epoxy composites applications.
{"title":"Flame retardant and anti-corrosion epoxy resin with strong mechanical property enabled by P/N/S ionic compound","authors":"Yan Zhang, Chenyu Zhou, Zhiquan Pan, Hong Zhou","doi":"10.1016/j.polymer.2025.128093","DOIUrl":"10.1016/j.polymer.2025.128093","url":null,"abstract":"<div><div>Optimal epoxy resin materials need to have a combination of excellent properties on flame retardance, smoke suppression, transparency and mechanical strength. However, the current strategy in the design for flame retardants tends to improve flame retardancy, while often accompanied by other performance deterioration. Herein, an ionic compound (A-D) verified with X-ray diffraction technology was synthesized by a simple acid-base neutralization reaction, and applied as a flame retardant agent for EP. EP/A-D thermoset showed good flame retardancy, confirmed by a high limiting oxygen index (LOI) of 36.5 % and a UL-94 V-0 rating when A-D addition was 6 %.The total smoke production (TSP) and total heat release rate (THR) decreased by 65.3 % and 41.9 % when compared with pure EP. The obvious decrease of TSP and THR was contributed to the radical capturing and catalytic charring endowed by A-D. Furthermore, EP/6A-D exhibited outstanding mechanical properties, the tensile strength and flexural strength of EP/6A-D increases by 40.4 % and 150.4 %, respectively, compared to pure EP. Such a strong mechanical strength has hardly been found in the modified EP reported in literatures. Furthermore, the EP composite also has good transparency, and better resistance to corrosion. The excellent overall properties endow EP/6A-D composites great potential for enlarging epoxy composites applications.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128093"},"PeriodicalIF":4.1,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050489","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 : 2025-01-28DOI: 10.1016/j.polymer.2025.128091
Yangyang Zheng , Huacheng Zhang
Organic aerogel has attracted much attention these days due to its wide applications to multiple daily fields. Except for designing processing procedures, we focused on enhancing the hierarchical porosities by introducing cavities of cyclodextrins (CDs) here in polymeric networks crosslinked by boric acid (BA). As confirmed by a series of instrumental analyses such as FT-IR, XRD, SEM, BET, EDS, XPS and ζ potential, BA was successfully employed as the “bridge-like” moieties to connect independent CDs subunits together for affording CDs-based polymers (BA-CD) via the one-step method in aqueous solutions. Particularly, BA-CD exhibited expected selective capacity during the experiment of competitive adsorption by fully using diverse porosities generated by both polymeric networks and the host cavities. Theoretical calculations were further performed to model the possible monomeric structure in BA-CD, and the diverse behaviors in host-guest inclusion towards targeted organic dyes by using CD and BA-mono-bridged CD dimeric structure, indicating that both molecular recognition of CD cavity and synergistic cooperation among crosslinked CD moieties play significant roles in selectively absorbing binary dyes.
{"title":"Boric acid bridged cyclodextrins-based polymers for selective adsorption of binary dyes","authors":"Yangyang Zheng , Huacheng Zhang","doi":"10.1016/j.polymer.2025.128091","DOIUrl":"10.1016/j.polymer.2025.128091","url":null,"abstract":"<div><div>Organic aerogel has attracted much attention these days due to its wide applications to multiple daily fields. Except for designing processing procedures, we focused on enhancing the hierarchical porosities by introducing cavities of cyclodextrins (CDs) here in polymeric networks crosslinked by boric acid (BA). As confirmed by a series of instrumental analyses such as FT-IR, XRD, SEM, BET, EDS, XPS and ζ potential, BA was successfully employed as the “bridge-like” moieties to connect independent CDs subunits together for affording CDs-based polymers (BA-CD) via the one-step method in aqueous solutions. Particularly, BA-CD exhibited expected selective capacity during the experiment of competitive adsorption by fully using diverse porosities generated by both polymeric networks and the host cavities. Theoretical calculations were further performed to model the possible monomeric structure in BA-CD, and the diverse behaviors in host-guest inclusion towards targeted organic dyes by using CD and BA-mono-bridged CD dimeric structure, indicating that both molecular recognition of CD cavity and synergistic cooperation among crosslinked CD moieties play significant roles in selectively absorbing binary dyes.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128091"},"PeriodicalIF":4.1,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055280","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 : 2025-01-27DOI: 10.1016/j.polymer.2025.128076
M. Luo , F. Wei , C. Jiang , J.H. Zhang , W. Xu , J.D. Liu , B.J. Ye , H.J. Zhang
To improve the mechanical properties of carbon-fiber-reinforced polymers (CFRPs), various factors of microstructure were investigated, but the effect of free-volume holes was rarely studied. In this work, a series of CFRPs which were prepared from DGEBA (diglycidyl ether of Bisphenol A) epoxy resin and treated carbon fibers (TCF), were characterized by positron annihilation age-momentum correlation (AMOC) spectroscopy experiments to reveal their free-volume hole properties. The results of the parameter indicate that CFRPs and the DGEBA matrix have similar free-volume environments, which are primarily governed by the free-volume of DGEBA and the carbon fiber/matrix interface. From the positron annihilation lifetime (PAL) spectra derived from AMOC data, with increase of TCF content, CFRPs exhibit similar free-volume hole size, narrower hole size distribution, and lower fractional free-volume (FFV). To characterize the interfacial interaction between matrix and TCF for each sample, a parameter was calculated from PAL spectra results. Eventually, for TCF contents in the range from 39 to 58 wt%, five mechanical parameters (tensile strength, tensile modulus, flexural strength, flexural modulus, and shear modulus) are almost linearly and negatively correlated with both relative fractional free-volume (FFVr) and interfacial interaction parameter (). This work provides a specific free-volume perspective to understand the macroscopic mechanical properties of CFRPs.
{"title":"Effect of free-volume holes on mechanical properties of carbon-fiber-reinforced polymers (CFRPs) studied by positron annihilation age-momentum correlation spectroscopy","authors":"M. Luo , F. Wei , C. Jiang , J.H. Zhang , W. Xu , J.D. Liu , B.J. Ye , H.J. Zhang","doi":"10.1016/j.polymer.2025.128076","DOIUrl":"10.1016/j.polymer.2025.128076","url":null,"abstract":"<div><div>To improve the mechanical properties of carbon-fiber-reinforced polymers (CFRPs), various factors of microstructure were investigated, but the effect of free-volume holes was rarely studied. In this work, a series of CFRPs which were prepared from DGEBA (diglycidyl ether of Bisphenol A) epoxy resin and treated carbon fibers (TCF), were characterized by positron annihilation age-momentum correlation (AMOC) spectroscopy experiments to reveal their free-volume hole properties. The results of the <span><math><mrow><mi>S</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow></mrow></math></span> parameter indicate that CFRPs and the DGEBA matrix have similar free-volume environments, which are primarily governed by the free-volume of DGEBA and the carbon fiber/matrix interface. From the positron annihilation lifetime (PAL) spectra derived from AMOC data, with increase of TCF content, CFRPs exhibit similar free-volume hole size, narrower hole size distribution, and lower fractional free-volume (FFV). To characterize the interfacial interaction between matrix and TCF for each sample, a parameter <span><math><mi>β</mi></math></span> was calculated from PAL spectra results. Eventually, for TCF contents in the range from 39 to 58 wt%, five mechanical parameters (tensile strength, tensile modulus, flexural strength, flexural modulus, and shear modulus) are almost linearly and negatively correlated with both relative fractional free-volume (FFV<sub>r</sub>) and interfacial interaction parameter (<span><math><mi>β</mi></math></span>). This work provides a specific free-volume perspective to understand the macroscopic mechanical properties of CFRPs.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"320 ","pages":"Article 128076"},"PeriodicalIF":4.1,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050794","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 : 2025-01-27DOI: 10.1016/j.polymer.2025.128088
Huashuai Cui , Zetian Zhang , Qing Huang
The increasing concerns over pollution from non-degradable plastics are prompting a quest for sustainable alternatives. Polyglycolic acid (PGA), known for its good biocompatibility and high mechanical strength, faces limited applications due to its uncontrollable degradation rate. This article introduces an effective approach to enhance the shelf life of PGA by constructing a novel “stereo-lock” structure. Stereocomplex polylactic acid (ScPLA) is first disassembled and fixed to the amorphous region of PGA by melt spinning. Later, an annealing process enhances molecular chain mobility, leading to the reformation of ScPLA and the locking of entangled PGA amorphous molecular chains, resulting in the formation of “stereo-lock” configurations. Thus, molecular chain density in the amorphous area increases, which reduces the accessibility of water to ester bonds and is conducive to improving the degradation resistance of PGA. As a result, compared to pure PGA, the rate of degradation of the monofilament possessing “stereo-lock” structure is noticeably slower. Specifically, by the seventh day of the accelerated degradation tests, the weight loss of the PGA monofilament dropped from 61.4 % to 48.4 % in the monofilament with “stereo-lock”. Furthermore, the formation mechanism of the “stereo-lock” was confirmed through a series of investigations and analyses. The structure-property relationship between molecular chain entanglement and degradation properties of PGA was studied systematically in this study, which also offers fresh perspectives on how to control the degradation characteristics of other polymers.
{"title":"Enhancing degradation resistance of polyglycolic acid through stereocomplex polylactic acid integration: A novel “stereo-lock” approach","authors":"Huashuai Cui , Zetian Zhang , Qing Huang","doi":"10.1016/j.polymer.2025.128088","DOIUrl":"10.1016/j.polymer.2025.128088","url":null,"abstract":"<div><div>The increasing concerns over pollution from non-degradable plastics are prompting a quest for sustainable alternatives. Polyglycolic acid (PGA), known for its good biocompatibility and high mechanical strength, faces limited applications due to its uncontrollable degradation rate. This article introduces an effective approach to enhance the shelf life of PGA by constructing a novel “<em>stereo-lock</em>” structure. Stereocomplex polylactic acid (ScPLA) is first disassembled and fixed to the amorphous region of PGA by melt spinning. Later, an annealing process enhances molecular chain mobility, leading to the reformation of ScPLA and the locking of entangled PGA amorphous molecular chains, resulting in the formation of “<em>stereo-lock</em>” configurations. Thus, molecular chain density in the amorphous area increases, which reduces the accessibility of water to ester bonds and is conducive to improving the degradation resistance of PGA. As a result, compared to pure PGA, the rate of degradation of the monofilament possessing “<em>stereo-lock</em>” structure is noticeably slower. Specifically, by the seventh day of the accelerated degradation tests, the weight loss of the PGA monofilament dropped from 61.4 % to 48.4 % in the monofilament with “<em>stereo-lock</em>”. Furthermore, the formation mechanism of the “<em>stereo-lock</em>” was confirmed through a series of investigations and analyses. The structure-property relationship between molecular chain entanglement and degradation properties of PGA was studied systematically in this study, which also offers fresh perspectives on how to control the degradation characteristics of other polymers.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"321 ","pages":"Article 128088"},"PeriodicalIF":4.1,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143044385","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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