{"title":"3D/4D printed bio-composites reinforced by bamboo charcoal and continuous flax fibres for superior mechanical strength, flame retardancy and recoverability","authors":"Mahdi Bodaghi , Kaveh Rahmani , Mohammadreza Lalegani Dezaki , Callum Branfoot , Jon Baxendale","doi":"10.1016/j.polymertesting.2025.108709","DOIUrl":"10.1016/j.polymertesting.2025.108709","url":null,"abstract":"<div><div>This study explores development and 3D/4D printing of environmentally friendly bio-composites with enhanced mechanical properties, flame retardancy, and shape memory capabilities. Composite filaments were created by incorporating polylactic acid (PLA) with bamboo charcoal (BC) and then printed using a modified printer equipped with a dual-feed system to accommodate both PLA/BC filaments and continuous flax fibres (CFF). SEM revealed strong fibre-matrix bonding with minimal voids, indicating good interfacial adhesion. Bio-composite properties were characterised through DMA, tensile, three-point bending, flammability, and shape-memory effect tests. Adding 3 wt% BC and CFF significantly increased the tensile strength by 248 % and the flexural strength by 207 % compared to pure PLA. Flame retardancy properties were notably improved, with a 50 % reduction in the burning rate, and underwriters’ laboratories (UL-94) rate and limiting oxygen index (LOI) reached to V-1 rating and 36.8%vol, respectively. DMA tests showed an increase in storage modulus, indicating improved stiffness. Shape memory tests under cold/hot programming protocols demonstrated efficient shape fixation with shape recovery ratios reaching up to 98.9 % for pure PLA and 89 % for PLA/BC/CFF for hot programming. Finally, a conceptual meta-bio-composite was 4D printed, showcasing key achievements such as quasi-zero stiffness, constant force behaviour, enhanced energy absorption/dissipation, and excellent recoverability and reusability. This highlights their potential for applications requiring durability, safety, comfort, and sustainability in sectors such as automotive, aerospace, logistics, construction, and furniture.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108709"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polymer TestingPub Date : 2025-02-01DOI: 10.1016/j.polymertesting.2025.108703
Wentao Yang, Yang Jin, Zhengyan Yang, Diantang Zhang
{"title":"High-temperature tensile mechanical behavior and ablation mechanisms of three-dimensional multi-directions braided carbon/boron-modified phenolic composites","authors":"Wentao Yang, Yang Jin, Zhengyan Yang, Diantang Zhang","doi":"10.1016/j.polymertesting.2025.108703","DOIUrl":"10.1016/j.polymertesting.2025.108703","url":null,"abstract":"<div><div>Three-dimensional (3D) braiding structures provide the solution strategy for both the high bearing capacity and low ablation of the new thermal protection systems. In this paper, two kinds of carbon/phenolic 3D braided composites, three-dimensional five-directional (3D5d) and three-dimensional six-directional (3D6d),were prepared. A combination of experimental and numerical simulations was used to reveal the Tensile damage mechanism of the materials at room (25 °C) and elevated (200 °C) temperatures. In addition, ablation tests of 3D5d and 3D6d were conducted for 30s and 60s. The results show that the high-temperature tensile mechanical behaviors and ablation mechanisms both exhibit the obvious structure effects. In detail, the tensile strength of 3D5d is 20.17 % and 17.86 % higher than those of 3D6d at room and elevated temperatures, respectively. The high-temperature tensile damage pattern of 3D5d includes shear fracture of braiding yarns, tensile fracture of fifth yarns, matrix softening and interfacial debonding. 3D6d has an additional sixth yarn tearing. Furthermore, the linear ablation rate, mass ablation rate, and crack volume fraction of 3D6d are 11.6 %, 13.9 %, 12.67 % lower than those of 3D5d after ablation for 60s. In 3D5d, ablation cracks extend along braiding yarns and fifth yarn. In contrast, 3D6d has additional cracks extending along sixth yarn.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108703"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polymer TestingPub Date : 2025-02-01DOI: 10.1016/j.polymertesting.2025.108728
Qun Huang, Zhibing Zhang
{"title":"Microencapsulation of L-carvone and hexyl salicylate in carnauba wax, candelilla wax and beeswax by melt dispersion method","authors":"Qun Huang, Zhibing Zhang","doi":"10.1016/j.polymertesting.2025.108728","DOIUrl":"10.1016/j.polymertesting.2025.108728","url":null,"abstract":"<div><div>Wax microspheres encapsulating flavour or fragrance oil (L-carvone, Hexyl salicylate) prepared via melt dispersion was investigated. This study highlights the influence of different waxes as well as variable oil loadings on the fundamental properties of the resulting microparticles. The mechanical characterisation of individual wax microspheres by a micromanipulation technique is firstly reported here and the values of Young's modulus of wax microspheres were determined by fitting the experimental force versus displacement with the Hertz model. The relation between the payload and Young's modulus of wax microsphere was also explored in this study.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108728"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polymer TestingPub Date : 2025-02-01DOI: 10.1016/j.polymertesting.2025.108702
Jeong Hwan Kim , Dongwon Ha , Min-Sung Kim , Gun Jin Yun
{"title":"Experimental investigation of freeze-thaw environmental effects on the fatigue life of CFRP composites","authors":"Jeong Hwan Kim , Dongwon Ha , Min-Sung Kim , Gun Jin Yun","doi":"10.1016/j.polymertesting.2025.108702","DOIUrl":"10.1016/j.polymertesting.2025.108702","url":null,"abstract":"<div><div>This paper investigates the effect of Freeze-Thaw (FT) environments on the fatigue behavior of carbon fiber-reinforced polymer (CFRP) composites under extreme conditions. The effect of FT cycles on CFRP fatigue life has not been previously studied. In this paper, three types of specimens (open-hole, transverse, and shear) were subjected to FT cycles: freezing at −60 °C and thawing at 30 °C. Open-hole specimens (OHS) were subjected to 0, 50, and 100 FT cycles before being tested at stress ratios R = 10 and R = −1, while transverse (TS) and shear specimens (SS) were exposed to 0 and 100 FT cycles and tested under R = −1. Fracture surfaces were analyzed using Scanning Electron Microscopy (SEM). SEM observations revealed that the FT cyclic environment weakened the fiber-matrix bond across all specimens. However, the fatigue life of CFRP is primarily governed by dominant failure mechanisms, which depend on the stress ratio and laminate configuration. In SS, where fiber-matrix debonding is the primary failure mechanism, the FT environment directly affected fatigue life, significantly reducing fatigue resistance. In contrast, the fatigue life of OHS and TS was predominantly determined by the specific failure mechanisms characteristic of each laminate rather than being directly influenced by the FT environment.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108702"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polymer TestingPub Date : 2025-02-01DOI: 10.1016/j.polymertesting.2025.108721
Setareh Zakeri , Antonia Ressler , Piie Konnunaho , Teemu Sandblom , Joshua Cunningham , Milla Rinne , Matti Järveläinen , Anastasia Elias , Erkka J. Frankberg , Erkki Levänen
{"title":"Chemical structure–property relationships of photocurable monomers/macromers: Potential binder candidates for ceramic/metal vat photopolymerization","authors":"Setareh Zakeri , Antonia Ressler , Piie Konnunaho , Teemu Sandblom , Joshua Cunningham , Milla Rinne , Matti Järveläinen , Anastasia Elias , Erkka J. Frankberg , Erkki Levänen","doi":"10.1016/j.polymertesting.2025.108721","DOIUrl":"10.1016/j.polymertesting.2025.108721","url":null,"abstract":"<div><div>Successful ceramic/metal vat photopolymerization (VPP) depends on the precise optimization of photocurable polymers to achieve ideal component properties. Most photocurable polymers consist of binary systems with monomers/macromers of varying functionalities. Crosslinking polymerization in VPP, particularly concerning monomer/macromer chemical structure, has not been extensively researched. This study systematically investigates the effects of three difunctional monomers, three difunctional macromers, and three multifunctional monomers. 18 combinations were prepared using difunctional monomers/macromers and multifunctional monomers at a 50:50 ratio. The study examined how linker chain length, ethoxylation, functional groups, and functionality impact properties critical for VPP processes, including photocuring behavior, mechanical properties, and shrinkage. Curing depth measurements showed that resins with rigid monomers and longer chain lengths had a higher critical energy (<span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>), while flexible monomers had a lower <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>. Methacrylate-containing formulations exhibited a higher <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> than acrylates. Although resins with higher functionality (<span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>a</mi><mi>v</mi><mi>e</mi></mrow></msub></math></span>) generally showed higher <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>, this trend was not always consistent. Photo-DSC results showed that ethoxylated TMPTA slows down crosslinking polymerization in methacrylate-containing resins but accelerates it in acrylate formulations. Moreover, combining tetrafunctional monomer with methacrylate enhanced the polymerization rate of methacrylate. The compression tests showed that an excess of ethylene oxide groups in the chemical structure of used monomers introduces a higher degree of flexibility and softness to the cured structure, leading to a reduction in mechanical properties. Furthermore, it was observed that methacrylate-containing resins shrank more compared to their acrylate-containing counterparts. Finally, five potential candidates were proposed for ceramic/metal VPP.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108721"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Resistance of CNT film toughened composite laminates under high-speed impact: Experimental and numerical study","authors":"L.I. Zhouyi , L.I. Jiming , L.I.U. Yan , J.I.A. Pengcheng , C.H.A.O. Huan","doi":"10.1016/j.polymertesting.2025.108712","DOIUrl":"10.1016/j.polymertesting.2025.108712","url":null,"abstract":"<div><div>This paper conducted high-speed impact tests for the carbon fiber resin matrix composite laminates toughened by multi-walled carbon nanotubes (MWCNTs) interlayers. Numerical simulations were conducted based on the tests by using the cohesive model with rate sensitivity and CNT toughening mechanism. It shows that the FEM (Finite element method) model can effectively predict the impact behavior of CNTs interlaminar toughened composites under high-speed impact. The influence and mechanism of CNTs on materials under impact were revealed, and it was found that the addition of CNTs can help materials resist delamination during impact and ensure the integrity of the laminate structure.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108712"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polymer TestingPub Date : 2025-02-01DOI: 10.1016/j.polymertesting.2024.108685
Jinxin Wu , Bing Han , Shili Ai , Aijing Wang , Yilin Song , Moran Jin , Xiaozhong Qu , Xiaoyan Wang
{"title":"Injectable double network hydrogel with adjustable stiffness for modulation of macrophage polarization","authors":"Jinxin Wu , Bing Han , Shili Ai , Aijing Wang , Yilin Song , Moran Jin , Xiaozhong Qu , Xiaoyan Wang","doi":"10.1016/j.polymertesting.2024.108685","DOIUrl":"10.1016/j.polymertesting.2024.108685","url":null,"abstract":"<div><div>Substrate stiffness can regulate macrophage polarization to support tissue repair in tissue engineering applications. Understanding the mechanisms of stiffness sensing is valuable for applying this knowledge to stiffness-related inflammatory diseases. In this study, we examined IACs-related integrins related to stiffness-sensitive macrophage polarization by constructing an injectable double-network (DN) hydrogel with varying stiffness. Inflammatory cytokine expression decreased as substrate stiffness increased (from 19.9 to 125.7 kPa), with medium stiffness (84.8 kPa) inducing macrophages to an increased level of anti-inflammatory polarization. Improved adhesion and elevated expression levels of ITGA5, ITGA3, and ITGAV in macrophages on the softer hydrogels highlighted the role of integrins in stiffness-regulated macrophage polarization. Inhibition of integrins using ethylenediaminetetraacetic acid (EDTA) abolished differences in macrophage polarization across the three groups, further confirming the central role of integrins. These findings suggest that, in tissue engineering, selecting appropriate substrate stiffness or gradient stiffness hydrogel could align with the optimal mechanical environment required for specific cell growth and function. Additionally, the critical role of integrins in mediating mechanical transduction may provide new therapeutic targets for treating certain stiffness-related inflammatory diseases.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108685"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polymer TestingPub Date : 2025-02-01DOI: 10.1016/j.polymertesting.2025.108688
E.H. Plaschka, K. Akutagawa, E. Di Federico, J.J.C. Busfield
{"title":"Developing a more representative friction and wear simulator for tire tread compounds","authors":"E.H. Plaschka, K. Akutagawa, E. Di Federico, J.J.C. Busfield","doi":"10.1016/j.polymertesting.2025.108688","DOIUrl":"10.1016/j.polymertesting.2025.108688","url":null,"abstract":"<div><div>This study outlines a novel method to evaluate friction and wear performance in tire tread compounds. This new laboratory method takes into account the realistic contact force of a tread block impacting the road during each revolution of the tire. The dynamic contact between the sample and the abrader is simulated in a manner which more closely replicates a real tire's contact behaviour. The contact period accounts for the correct timing and the contact pressure that is typical for a passenger car driving under low-speed conditions. Two styrene-butadiene rubber (SBR) tyre tread compounds each filled with the same volume fraction of carbon black were vulcanized and abraded under this loading sequence. An analysis of the friction and the evolution of wear morphology are described in detail to provide insight into the governing mechanisms that determine tire tread performance.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108688"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polymer TestingPub Date : 2025-02-01DOI: 10.1016/j.polymertesting.2025.108719
Cheng Liu , Dongyang Zhuang , Yan Zhou , Jihua Liao , Shengping Dai , Changwang Pan , Yuntong Li , Lizong Dai , Wei Wang
{"title":"Mechanically reinforced and flame-retardant epoxy resin nanocomposite based on molecular engineering of POSS","authors":"Cheng Liu , Dongyang Zhuang , Yan Zhou , Jihua Liao , Shengping Dai , Changwang Pan , Yuntong Li , Lizong Dai , Wei Wang","doi":"10.1016/j.polymertesting.2025.108719","DOIUrl":"10.1016/j.polymertesting.2025.108719","url":null,"abstract":"<div><div>The existing flame retardants are extensively utilized for epoxy resin (EP) in the field of engineering materials with good flame retardancy. Nevertheless, their introduction often brings a substantial decrease in mechanical properties of EP. To tackle this challenge, a multifunctional nano flame-retardant (PoDOH) that is designed to enhance both the flame-retardant and mechanical properties for EP simultaneously was synthesized in this study. The results demonstrate that for EP-10 %, its hardness increased by 34.8 %, and Young's modulus increased by 25.4 %, respectively, owing to the strong interfacial interaction among EP and PoDOH derived from the ring-opening reaction. Moreover, the synergistic action of the various flame retardant elements present in PoDOH imparts excellent flame retardancy to EP-10 % (V-0 rating, LOI = 32.6 % and PHRR decreased by 48.82 %). These findings indicate that PoDOH holds great potential as a versatile and efficient flame retardant for manufacturing high-performance EP.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":"143 ","pages":"Article 108719"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}