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1.
Int J Biol Macromol ; 279(Pt 3): 135289, 2024 Sep 03.
Article in English | MEDLINE | ID: mdl-39236958

ABSTRACT

With increasing environmental awareness and the pursuit of sustainable development goals, environmentally friendly sustainable thermoplastic elastomers (TPEs) derived from natural resources are highly desired to replace traditional TPEs. However, preparing sustainable TPEs with high mechanical properties and multifunctionality from biobased feedstocks remains a significant challenge. In this work, a series of chitin-graft-poly(acrylamide-co-2-ethylhexyl acrylate) (Chitin-g-P(AM-co-EHA)) copolymers were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization. The tensile strength of Chitin-g-P(AM-co-EHA) copolymers can be tuned over a wide range from 1.0 to 7.3 MPa by adjusting the chitin and PAM contents. Benefiting from the brush-like architecture, Chitin-g-P(AM-co-EHA) copolymer exhibits improved mechanical properties over its linear counterparts. Moreover, these Chitin-g-P(AM-co-EHA) copolymers show good adhesion performance on different substrates. The shear strength can achieve 7.5 MPa for Chitin0.8-PAM50, which is high enough for commercial applications. The combination of chitin and grafting strategy can promote the development of strong chitin-based sustainable elastomers. This approach can be further utilized to design novel high-performance biobased elastomers and adhesives derived from natural resources.

2.
J Mech Behav Biomed Mater ; 159: 106694, 2024 Aug 20.
Article in English | MEDLINE | ID: mdl-39191061

ABSTRACT

The demand for synthetic bone graft biomaterials has grown in recent years to alleviate the dependence on natural bone grafts and metal prostheses which are associated with significant practical and clinical issues. Biopolymer nanocomposites are a class of materials that display strong potential for these synthetic materials, especially when processed using additive manufacturing technologies. Novel nanocomposite biomaterials capable of masked stereolithography printing have been developed from functionalized plant-based monomers and hydroxyapatite (HA) with mechanical properties exceeding those of commercial bone cements. However, these biomaterials have not been evaluated under relevant physiological conditions. The effects of temperature (room temperature vs. 37 °C) and water absorption on the physical, surface, and mechanical properties of HA-containing biopolymer nanocomposites were investigated. Exposure to relevant conditions led to substantial impacts on material performance, such as significantly reduced mechanical strength and stiffness. For instance, a composite containing 10 vol% HA and functionalized monomers had 26 and 21% reductions in compressive yield strength and elastic modulus, respectively. After 14 days incubation in phosphate buffered saline, the same composition displayed a 62% decrease in compressive yield strength to 28 MPa. This manuscript demonstrates the relevance and importance of evaluating biomaterials under appropriate physiological conditions throughout their development and provides direction for future material development of HA-containing biopolymer nanocomposites.

3.
Nanomaterials (Basel) ; 14(15)2024 Jul 30.
Article in English | MEDLINE | ID: mdl-39120390

ABSTRACT

This study aimed to investigate the potential of antimony-doped tin oxide (ATO) as a reinforcing agent for polyamide 12 (PA12) in 3D printing by examining four mixtures with varying ATO concentrations (2.0 to 8.0 wt.%, with a 2.0 wt.% interval). These mixtures were used to fabricate filaments for the manufacturing of specimens through the material extrusion method. The mechanical properties of the resulting PA12/ATO composites and PA12 pure samples were evaluated through tensile, Charpy impact, flexural, and microhardness tests. Additionally, rheology, structure, morphology, thermal properties, pore size, and consistency in the dimensions of the samples were evaluated. Thermogravimetric analysis, along with differential scanning calorimetry, scanning electron microscopy, energy-dispersive and Raman spectroscopy, and micro-computed tomography, were conducted. The results were correlated and interpreted. The greatest reinforcement was achieved with the PA12/ATO 4.0 wt.% mixture, which exhibited a 19.3% increase in tensile strength and an 18.6% increase in flexural strength compared with pure PA12 (the control samples). The Charpy impact strength and microhardness were also improved by more than 10%. These findings indicate the merit of composites with ATO in additive manufacturing, particularly in the production of components with improved mechanical performance.

4.
Int J Biol Macromol ; : 134705, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39214833

ABSTRACT

Combining thermal conductive fillers and flexible polymers is an agile approach to fabricating composites with heat-conducting performance. However, the thermal conductivity of the composites is hard to reach an equal level to the functional fillers. The mainspring is that the thermally conductive pathways within the composite could not be well-constructed due to the air-induced interface thermal resistance. Herein, inspired by the plant cell wall structure, polyvinyl alcohol (PVA) with abundant hydroxyl groups was adopted as a binder for boosting the thermally conductive pathways construction between cellulose nanofiber (CNF) and alkalized hexagonal boron nitride (BN-OH), also for strengthening the mechanical performance of the composite. The results showed that the tensile strength and through-plane thermal conductivity of the composite were high up to 91.0 MPa and 2.2 W m-1 K-1 at 40 wt% PVA content, exhibiting 121 % and 450 % enhancements compared to pure CNF film (41.2 MPa and 0.4 W m-1 K-1). Moreover, the composite also presented high thermal stability (decomposition temperature of onset was 218 °C) and good hydrophobicity properties. Overall, this study innovatively proposes an idea for enhancing the thermal conductivity and improving the mechanical properties of the composite, which is indispensable for developing thermal management materials for next-generation electronics.

5.
Materials (Basel) ; 17(16)2024 Aug 06.
Article in English | MEDLINE | ID: mdl-39203077

ABSTRACT

This study investigated the utilization of innovative green composites made from hemp shiv, a waste by-product of hemp cultivation, with the aim of promoting sustainability within the construction industry. The manufacturing method involved the application of pressure in a mold to create the samples. These materials were produced using an environmentally friendly binder consisting of colophony, arabic gum, and corn starch. Moreover, white glue and bioepoxy were also used to compare with the green resins. Three different binder compositions were used for the specimens. The samples underwent mechanical testing through tensile and bending assessments, and their performance was compared to that of non-green binders to validate the effectiveness of the manufacturing processes. The study revealed that decreasing the moisture content during the curing process was crucial for improving the mechanical properties. The best results were achieved when using arabic gum as a binder, yielding a tensile strength of 2.16 MPa and a bending strength of 5.25 MPa, with a composition of 62.5% hemp shiv and a manufacturing process involving a pressure of 5 MPa.

6.
Materials (Basel) ; 17(14)2024 Jul 10.
Article in English | MEDLINE | ID: mdl-39063700

ABSTRACT

Plastic waste management has received significant attention in recent decades due to the urgent global environmental crisis caused by plastic pollution. The versatile and durable nature of plastic has led to its widespread usage across various sectors. However, its nonbiodegradable nature contributes to unsustainable production practices, leading to extensive landfill usage and posing threats to marine ecosystems and the food chain. To address these environmental concerns, numerous challenges have been recently addressed through investigating alternative approaches for disposing of plastic waste, with the construction sector emerging as a promising option. Incorporating plastic waste materials into concrete not only offers economic benefits but also provides a valid alternative to conventional disposal methods. This paper presents the results of different experimental studies, some of them available in the literature and others new, discussing the feasibility of integrating plastic waste into concrete and its impact on mechanical properties. The influence of different sizes, natures, treatments, and percentages of plastic waste in the concrete mixtures is dealt with in order to provide further data for helping to understand the nonunivocal results in the literature, under the conviction that only further observations can help to understand the mechanics of concrete with plastic aggregates. The experimental investigation highlighted that one parameter that is better than others and can be considered to compare different experimental investigations is the variation in weight (due to the effective volume of plastics in the mix), determining a sort of increasing of porosity that degrades the mechanical characteristics. However, this seems inconsistent in some cases. Therefore, the need for further research is highlighted to refine production methods and optimize mix designs.

7.
Environ Sci Pollut Res Int ; 31(36): 48908-48927, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39085691

ABSTRACT

There is a global concern with continuous waste production, and efforts are underway to use these wastes in the construction sector. The negative effects of excessive waste production and the use of virgin materials and energy in Hot Mix Asphalt (HMA) construction are challenging and require attention. The right step towards developing resilient road infrastructure is using cold bitumen emulsion mixtures (CBEMs), a cold mix asphalt (CMA). A long-term fix to issues with waste generation and the creation of flexible pavements with HMA can be found by incorporating wastes into CMA. This work reviews the utilization of numerous wastes from different sectors (agricultural, industrial, construction and demolition, and municipal) that are well-known but underutilized and could be used as potential fillers in cold asphalt mixtures. Focus is given to the critical analysis of wastes' physiochemical characteristics and how these affected the effectiveness of mixtures against primary distresses like stability, stiffness, rutting, cracking, fatigue, and moisture susceptibility. Almost all waste materials incorporation reported enhancement in the mechanical performance of CBEM mixes concerning conventional CBEM mixes. The paper sums up the impact on various mechanical properties of CBEM mixes utilizing waste material filler, presents research gaps and a way forward to inspire researchers, and serves as a guideline for using waste materials as fillers in CBEM mixes. This will improve environmental quality and promote sustainability in the paving industry.


Subject(s)
Construction Materials , Hydrocarbons , Solid Waste , Emulsions
8.
Sci Total Environ ; 947: 174459, 2024 Oct 15.
Article in English | MEDLINE | ID: mdl-38964397

ABSTRACT

In this study, coal-based solid waste geopolymer mortar (SWCB) was prepared by using granulated ground blast-furnace slag (GGBS) and coal gasification coarse slag (CGCS) as precursors, and soda residue (SR) and phosphogypsum (PG) as activators, with gangue sand (GS) utilized as an inert filler. The corresponding compressive strength, fluidity, ion leaching, and microstructure of the developed SWCB were systematically investigated under varying solid contents, binder-to-sand ratios, and activator ratios. The findings suggest that the incorporation of activators promoted the dissolution of the silicon-aluminum phase in GGBS and CGCS into Al(OH)4-, [SiO(OH)3]-, and [SiO2(OH)2]2-, which could subsequently react with the Ca2+ and SO42- released by PG, forming AFt and C-(A)-S-H, thereby playing a crucial role in enhancing matrix strength. AFt was the predominant hydration product in the early reaction stage. The morphology of the AFt phase evolved from needle-like or filamentous to fine and coarse rods as hydration progressed. Initially, the formation of C-(A)-S-H gel increased with rising activator content before decreasing. The optimal synergy between AFt and C-(A)-S-H was observed at an activator content of 30 %. However, the growth of gypsum crystals was hindered when the activator content surpassed 30 %, resulting in a plate-like or columnar morphology. C-(A)-S-H gel exhibited remarkable adsorption capability towards P atoms attributed to intermolecular Van der Waal's forces, enabling simultaneous physical encapsulation of P atoms, while Cl element immobilization was primarily attributed to the contribution of SiOH sites to Cl adsorption.

9.
J Colloid Interface Sci ; 674: 695-701, 2024 Nov 15.
Article in English | MEDLINE | ID: mdl-38950468

ABSTRACT

Compared to the great achievements in enhancing thermoelectric (TE) performance, little attention is paid to the mechanical (ME) performance of polymer composites although it is a prerequisite for practical applications. However, how to improve a trade-off between TE and ME performance is a great challenge, as the increase in ME performance is always along with the decrease in TE performance and vice versa. Herein, an enhanced trade-off is realized for ionic liquid (IL)-modulated flexible poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/ single-walled carbon nanotube (SWCNT)/polycarbonate (PC) composites. It shows a maximum power factor value of 8.5 ± 2.1 µW m-1 K-2 and a strong mechanical robustness is also achieved for the composite with a fracture strength of 43.4 ± 5.4 MPa and a tensile modulus of 3.8 ± 0.4 GPa. The TE and ME performances are superior to other thermoplastics-based TE composites, and even comparable to some conducting polymers and their composites. The high electrical conductivity of PEDOT:PSS/SWCNT and their strong interfacial interaction with PC are responsible for the enhanced trade-off between ME and TE performances. This work provides a new avenue to endow polymer composites with high TE and ME performances simultaneously and will promote their versatile TE applications.

10.
Materials (Basel) ; 17(13)2024 Jun 26.
Article in English | MEDLINE | ID: mdl-38998210

ABSTRACT

Vat photopolymerization (VPP), as an additive manufacturing (AM) technology, can conveniently produce ceramic parts with high resolution and excellent surface quality. However, due to the inherent brittleness and low toughness of ceramic materials, manufacturing defect-free ceramic parts remains a challenge. Many researchers have attempted to use carbon fibers as additives to enhance the performance of ceramic parts, but these methods are mostly applied in processes like fused deposition modeling and hot pressing. To date, no one has applied them to VPP-based AM technology. This is mainly because the black carbon fibers reduce laser penetration, making it difficult to cure the ceramic slurry and thus challenging to produce qualified ceramic parts. To address this issue, our study has strictly controlled the amount of carbon fibers by incorporating trace amounts of carbon fiber powder into the original ceramic slurry with the aim to investigate the impact of these additions on the performance of ceramic parts. In this study, ceramic slurries with three different carbon fiber contents (0 wt.%, 0.1 wt.%, 0.2 wt.%, and 0.3 wt.%) were used for additive manufacturing. A detailed comparative analysis of the microstructure, physical properties, and mechanical performance of the parts was conducted. The experimental results indicate that the 3D-printed alumina parts with added carbon fibers show varying degrees of improvement in multiple performance parameters. Notably, the samples prepared with 0.2 wt.% carbon fiber content exhibited the most significant performance enhancements.

11.
Materials (Basel) ; 17(13)2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38998289

ABSTRACT

Polycarbonate (PC) as a widely used engineering plastic that shows disadvantages of flammability and large smoke production during combustion. Although many flame-retardant PCs have been developed, most of them show enhanced flame retardancy but poor smoke suppression or worsened mechanical performance. In this work, a novel nitrogen-phosphorus-sulfur synergistic flame retardant (Pc-FR) was synthesized and incorporated into PC with polytetrafluoroethylene (PTFE). The extremely low content of PC-FR (0.1-0.5 wt%) contributes significantly to the flame retardancy, smoke suppression and mechanical performance of PC. PC/0.3 wt% Pc-FR/0.3 wt% PTFE (PC-P0.3) shows the UL-94 V-0 and LOI of 33.5%. The PHRR, THR, PSPR, PCO and TCO of PC-P0.3 decreased by 39.44%, 14.38%, 17.45%, 54.75% and 30.61%, respectively. The impact strength and storage modulus of PC-P0.1 increased by 7.7 kJ/m2 and 26 MPa, respectively. The pyrolysis mechanism of PC-P0.3 is also revealed. The pyrolysis mechanism of PC-P0.3 is stochastic nucleation and subsequent growth and satisfies the Aevrami-Erofeev equation. The reaction order of PC-P0.3 is 1/2. The activation energy of PC-P0.3 is larger than PC-0, which proves that the Pc-FR can suppress the pyrolysis of the PC. This work offers a direction on how to design high-performance PC.

12.
Front Bioeng Biotechnol ; 12: 1397459, 2024.
Article in English | MEDLINE | ID: mdl-38846803

ABSTRACT

Preventing the occurrence of secondary caries serves as one of the significant issues in dental clinic, thus make it indispensable to improving the properties of conventional composite resin (CR) by developing a novel CR. In present study, two groups of experimental CRs loaded with different contents of fluoride-doped nano-zirconia fillers (25 wt% and 50 wt%) were fabricated. The surface topography, mechanical performance, fluoride release, antibacterial effect, aging property and cytotoxicity of the experimental CRs were evaluated subsequently. A uniform distribution of the F-zirconia fillers over the whole surface of resin matrix could be observed. The experimental CRs showed continuous fluoride release within 28 days, which was positively correlated with the content of F-zirconia fillers. Moreover, the amount of fluoride release increased in the acidic buffer. Addition of F-zirconia fillers could improve the color stability, wear resistance and microhardness of the experimental CRs, without reducing the flexure strength. Furtherly, the fluoride ions released continuously from the experimental CRs resulted in effective contact and antibacterial properties, while they showed no cytotoxicity. As a consequence, considerations can be made to employ this new kind of composite resin loaded with fluoride-doped nano-zirconia fillers to meet clinical requirements when the antimicrobial benefits are desired.

13.
Article in English | MEDLINE | ID: mdl-38837479

ABSTRACT

OBJECTIVE: To evaluate the mechanical performance of patient-specific prefabricated temporary shell versus laboratory-fabricated CAD/CAM provisional restorations on titanium temporary abutments, with and without thermo-mechanical ageing. MATERIALS AND METHODS: Implants with a conical connection were divided into four groups (n = 24) and restored with temporary shell or laboratory-fabricated central or lateral incisor PMMA restorations that were relined or bonded on titanium temporary abutments. The diameter of the central and lateral incisor groups' implants was regular (ϕ 4.3 mm) or narrow (ϕ 3.5 mm), respectively. Half of each group's specimens were subjected to ageing, simultaneous thermocycling (5-55°C) and chewing simulation (120,000 cycles, 50 N, 1.7 Hz) resulting in eight groups in total (n = 12). The aged specimens were evaluated with optical microscopy, and survival and complication rates were determined according to modified USPHS criteria. The non-aged specimens and those that had survived ageing were loaded until failure, whereupon bending moments were calculated. RESULTS: Survival rates after ageing were 100% for all groups. Apart from wear facets (ϕ 2-3 mm) on the palatal restoration surface, no complications were observed. The mean fracture load and bending moments ranged between 597.6-847.1 N and 433.3-550.6 Ncm, respectively, with no significant differences between the eight groups (p = .25; p = .20). CONCLUSIONS: As patient-specific temporary shell central and lateral incisor provisional implant-supported restorations are mechanically stable enough to withstand clinical bite forces, even after thermo-mechanical ageing, they may serve as an alternative to laboratory-fabricated provisional restorations.

14.
Materials (Basel) ; 17(12)2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38930240

ABSTRACT

In order to further optimize the performance of PMMA (Polymethyl Methacrylate) repair mortar. In this paper, fly ash, talcum powder and wollastonite powder are used as fillers to modify the PMMA repair mortar. The effects of these three fillers on the working performance, mechanical performance and durability of PMMA repair mortar were explored. The study shows that the three fillers have good effect on the bond strength of the repair mortar, in which the fly ash has the best effect on the mechanical performance. The mechanical properties of PMMA repair mortar were best when the amount of fly ash was 60 phr (parts per hundred, representing the amount of the material added per hundred parts of PMMA). At this time, the 28 d compressive strength was 71.26 MPa and the 28 d flexural strength was 28.09 MPa, which increased by 13.31% and 15.33%, respectively. Wollastonite powder had the least negative effect on the setting time of the PMMA repair mortar. When the dosage of wollastonite powder was increased to 100 phr, the setting time was only extended from 65 min to 94 min. When the talc dosage was 60 phr, the best improvement in salt freezing resistance was achieved. After 100 cycles of salt freezing, the mass loss rate and strength loss rate decreased to 0.159% and 4.97%, respectively, which were 75.1% and 37.7% higher than that of the control group. The addition of all three fillers reduced the porosity and the proportion of harmful pores in the mortar. This study contributes to a comprehensive understanding how different types of fillers affect PMMA repair mortars, and it also provides theoretical support for the further development of low-temperature rapid repair mortars.

15.
Materials (Basel) ; 17(12)2024 Jun 19.
Article in English | MEDLINE | ID: mdl-38930370

ABSTRACT

The effect of an alternative source of silica, based on class F fly ash mixed with blast furnace slag and activated by rice husk ash (RHA), to produce concrete exposed to marine environments was evaluated. Four mixtures activated by the combination of 85% NaOH 14M + 15% RHA were manufactured to achieve a liquid/solid ratio of 0.20. Fly ash was incorporated into the steel slag mixture at addition percentages of 20, 40, 60, and 80%, and evaluated at 28, 900, and 1800 days for pore and chloride ion absorption. In general, including rice husk ash in the mixture of fly ash and steel slag significantly affected mechanical performance because it was possible to obtain concrete with high mechanical resistance. Concerning the durability evaluation, the effect of the activator generated by rice husk ash was observed, and the increase in steel slag added to the cementitious samples improved the capacity of the material to resist the penetration and diffusion of chloride ions.

16.
Int J Biol Macromol ; 271(Pt 2): 132766, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38823742

ABSTRACT

The efficient development and utilization of green biomass-based macromolecule engineering materials are essential for the sustainable development of human civilization. In this study, lignin-based ethylene-propylene-diene-monomer (EPDM) composites with excellent mechanical performance were fabricated using a simple method. The effects of water-insoluble enzymatically hydrolyzed lignin (EL) and alkali lignin (KL) on the mechanical performance of the composites were investigated separately. The results showed that the tensile strength of EPDM reinforced with KL and EL increased to 24.5 MPa and 22.1 MPa, respectively, surpassing that of the carbon black (CB)-reinforced EPDM. After 72 h of thermo-oxidative aging, the retention rates of the tensile strength and elongation at break in the lignin-reinforced EPDM were much better than those formed with pure CB, indicating that lignin significantly improved the thermo-oxidative aging resistance of the composites. In summary, the Zn2+ coordination bonds formed between the interface of EPDM and lignin in lignin/CB/EPDM ternary composites effectively improved the mechanical performance and aging resistance of the composites. This study has significant implications for enhancing the utilization of lignin and green functional polymer materials.


Subject(s)
Lignin , Lignin/chemistry , Tensile Strength , Ethylenes/chemistry , Structure-Activity Relationship , Zinc/chemistry , Oxidation-Reduction , Cross-Linking Reagents/chemistry , Elastomers
17.
Heliyon ; 10(11): e32094, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38882316

ABSTRACT

Acrylonitrile butadiene styrene (ABS) composites were prepared in filament form compatible with the material extrusion (MEX) 3D printing method, using biochar as a filler at various loadings of up to 10.0 wt %. Samples were fabricated to experimentally investigate their mechanical performance. The ABS/biochar composites were characterized using thermogravimetric analysis, differential scanning calorimetry, Raman spectroscopy, and rheological tests. The electrical properties of the composites were investigated using broadband dielectric spectroscopy. Scanning electron microscopy was utilized to analyze the morphological features of the fabricated specimens by examining their side and fracture surfaces. The results indicate that the composite with 4.0 wt % biochar content compared to pure ABS showed the highest mechanical response between the prepared composites (24.9 % and 21 % higher than the pure ABS tensile and flexural strength respectively). The composites retained their insulating behavior. These findings contribute to expanding the utilization of the material extrusion (MEX) 3D printing method while also unlocking prospects for potential applications in microelectronics, apart from mechanical reinforcement.

18.
Materials (Basel) ; 17(9)2024 Apr 28.
Article in English | MEDLINE | ID: mdl-38730883

ABSTRACT

Impact tests on post-fire concrete confined by Carbon Fiber-Reinforced Polymer/Plastic (CFRP) sheets were carried out by using Split Hopkinson Pressure Bar (SHPB) experimental setup in this paper, with emphasis on the effect of exposed temperatures, CFRP layers and impact velocities. Firstly, according to the measured stress-strain curves, the effects of experiment parameters on concrete dynamic mechanical performance such as compressive strength, ultimate strain and energy absorption are discussed in details. Additionally, temperature caused a softening effect on the compressive strength of concrete specimens, while CFRP confinement and strain rate play a hardening effect, which can lead to the increase in dynamic compressive strength by 1.8 to 3.6 times compared to static conditions. However, their hardening mechanisms and action stages are extremely different. Finally, nine widely accepted Dynamic Increase Factor (DIF) models considering strain rate effect were summarized, and a simplified model evaluating dynamic compressive strength of post-fire concrete confined by CFRP sheets was proposed, which can provide evidence for engineering emergency repair after fire accidents.

19.
Materials (Basel) ; 17(9)2024 Apr 29.
Article in English | MEDLINE | ID: mdl-38730909

ABSTRACT

In this paper, the workability, mechanical, ion leaching, and drying shrinkage properties of alkali-activated concrete with recycled coarse and fine aggregates were studied, and the pore structure and micro-morphology of different alkali-activated recycled aggregate concretes (AARACs) were characterized by using the mercury intrusion method and scanning electron microscopy, respectively. The experimental results showed that with the increase in the replacement rate of the recycled fine aggregate (RFA), the flowability showed a decreasing trend. Adding a certain amount of RFA improves the mechanical properties of the AARAC. The compressive strength at a curing age of 28 days was 65.3 MPa with 70 wt% RFA replacement. When the replacement rate of the RFA was 100 wt%, the maximum splitting tensile strength (4.5 MPa) was obtained at a curing age of 7 days. However, the addition of the RFA had little effect on the flexural strength of the AARAC. As an extension of the curing age, the splitting tensile strength, flexural strength, tension-to-compression ratio, and flexure-to-compression ratio all showed an increasing trend at first and then a decreasing trend. At a curing age of 7 days, the tension-to-compression ratio and flexure-to-compression ratio were both high (except for those of R100), indicating that the ductility and toughness of the specimen were improved. The addition of the RFA increased the drying shrinkage of the AARAC. At a curing age of 120 days, compared to the specimen without the RFA, the drying shrinkage rate of the specimen with the addition of 70 wt% RFA increased by 34.15%. As the curing age increased, the microstructure of the reaction products became denser, but the proportion of large-diameter pores increased. This study evaluated the application of RFA in AARAC. The experimental results showed that the RFA-based AARAC had acceptable mechanical and durability properties.

20.
Article in English | MEDLINE | ID: mdl-38808689

ABSTRACT

The treatment of Giant Cell Tumor (GCT) in the distal radius poses challenges due to the intricate anatomical features of the bone. It often necessitates the use of long implant plates or the interconnection of multiple short plates after tumor excision. However, the deployment of metal plates may increase the risk of screw loosening and various complications. To address these challenges, this study proposes the adoption of carbon fiber-reinforced PEEK (CFRP) as the base material. As a unique strategy, performance parameters (PP) were developed to compare CFRP implant plates with a Ti-6Al-4V plate using the Finite-element Method. The focus was on four elements: the screw axial force, bone growth, callus formation, and bone resorption. The investigation into the screw axial force involved analyzing the internal force of the screw. The remaining parameters were evaluated using the stress, strain, or elastic energy induced in the bones. The findings showed that the second screw endured the largest screw axial force, measuring 10.16 N under a 90-degree 10-N loading at the translocated bone. The model without a callus exerted a significantly greater force on the screw than the model with a callus, leading to screw loosening in the early stage of treatment. The maximum PP, reached 1.62, was achieved with an angle-ply [456/-456] laminate, featuring a weighting fraction of 0.7 for bone growth and 0.1 for the other parameters. This study provides a generalized methodology for assessing the performances of CFRP implants and offers guidelines for future development in composite implant plate technology.

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