Journal of Composites Science

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15 pages, 6173 KiB

Open AccessArticle

Performance of GFRP-Confined Rubberized Engineered Cementitious Composite Columns

by Mahmoud T. Nawar, Mohamed Selim, Mahmoud Zaghlal, Ayman El-Zohairy and Mohamed Emara

J. Compos. Sci. 2024, 8(8), 330; https://doi.org/10.3390/jcs8080330 - 20 Aug 2024

Cited by 1 | Viewed by 636

Abstract

In coastal regions, the deterioration of structures and bridges due to environmental conditions and corrosion is a significant concern. To combat these issues, the use of corrosion-resistant materials like fiber-reinforced polymers (FRPs) materials, engineered cementitious composites (ECCs), and rubberized ECCs (RECC) shows promise [...] Read more.

In coastal regions, the deterioration of structures and bridges due to environmental conditions and corrosion is a significant concern. To combat these issues, the use of corrosion-resistant materials like fiber-reinforced polymers (FRPs) materials, engineered cementitious composites (ECCs), and rubberized ECCs (RECC) shows promise as normal concrete (NC) alternatives by providing increased ductility and energy absorption properties. The effectiveness of confining concrete columns using GFRP tubes with ECC/RECC was assessed in this research by evaluating their performance through compression and push-out tests. The study explored key parameters such as GFRP tube thickness and the presence of shear connectors along the tube height, as well as examining various types of concrete. Additionally, a comprehensive parametric investigation utilizing finite element analysis (FEA) was conducted to analyze how different factors influence the behavior of confined concrete columns. These factors included the effect of GFRP tube thickness and diameter on the overall behavior of different types of confined concretes. The results demonstrate that GFRP tubes significantly enhance column capacity, while the presence of ECC/RECC exhibits even greater improvements in capacity, stiffness, and toughness compared to NC. This approach shows promise in reinforcing coastal infrastructure and addressing corrosion-related concerns effectively. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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23 pages, 12323 KiB

Open AccessArticle

Correlation of Microstructural Features within Short Carbon Fiber/ABS Manufactured via Large-Area Additive- Manufacturing Beads

by Neshat Sayah and Douglas E. Smith

J. Compos. Sci. 2024, 8(7), 246; https://doi.org/10.3390/jcs8070246 - 28 Jun 2024

Cited by 1 | Viewed by 861

Abstract

Short carbon fiber-reinforced polymer composites are widely used in polymer extrusion additive manufacturing (AM), including large-area additive manufacturing (LAAM), due to their enhanced mechanical properties as compared to neat polymers. However, the mechanical properties of these composites depend on microstructural characteristics, including fibers [...] Read more.

Short carbon fiber-reinforced polymer composites are widely used in polymer extrusion additive manufacturing (AM), including large-area additive manufacturing (LAAM), due to their enhanced mechanical properties as compared to neat polymers. However, the mechanical properties of these composites depend on microstructural characteristics, including fibers and micro-voids, which are determined during processing. In this work, the correlation between fibers and micro-voids within the microstructure of LAAM polymer composites throughout various processing stages of short carbon fiber-reinforced acrylonitrile butadiene styrene (SCF/ABS) is investigated. The processing stages considered here include the incoming pellets, a single freely extruded strand, a single regularly deposited bead, and a single regularly deposited bead pressed by a mechanical roller. A high-resolution X-ray micro-computed tomography (µCT) system is employed to characterize the microstructural features in terms of the fibers (volume fraction, fiber orientation tensor) and micro-voids (volume fraction, sphericity) in the SCF/ABS samples. The results indicate that micro-voids exist within the microstructure of the SCF/ABS composite in all four stages considered here and that the micro-void volume fraction and micro-void sphericity vary among the test samples. Moreover, the results show a considerable variation in fiber orientation and fiber volume fraction within the microstructure throughout all the stages considered; however, all the samples show the highest alignment in the extrusion/print direction. Furthermore, a correlation is identified between the fiber orientation and the micro-void volume fraction within samples from all four stages considered here. This finding suggests that fibers tend to align more in the extrusion/print direction in regions with less micro-void content. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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14 pages, 3969 KiB

Open AccessArticle

Characterization of Posidonia oceanica Fibers High-Density Polyethylene Composites: Reinforcing Potential and Effect of Coupling Agent

by Manel Haddar, Ahmed Elloumi, Cheldly Bradai and Ahmed Koubaa

J. Compos. Sci. 2024, 8(7), 236; https://doi.org/10.3390/jcs8070236 - 24 Jun 2024

Cited by 1 | Viewed by 981

Abstract

This study investigated the influence of fiber loading and maleated polyethylene (MAPE) coupling agent on the structural, thermal, mechanical, morphological properties, and torque rheology of high-density polyethylene (HDPE) reinforced with Posidonia oceanica fiber (POF) composites. HDPE/POF composites, both with and without MAPE, were [...] Read more.

This study investigated the influence of fiber loading and maleated polyethylene (MAPE) coupling agent on the structural, thermal, mechanical, morphological properties, and torque rheology of high-density polyethylene (HDPE) reinforced with Posidonia oceanica fiber (POF) composites. HDPE/POF composites, both with and without MAPE, were manufactured using a two-step process: composite pellets extrusion, followed by test samples injection molding with various POF loadings (0, 20, 30, and 40 wt%). HDPE/POF composites reinforced with higher loading of POF (40 wt%) exhibit superior stiffness, better crystallinity, and higher stabilized torque and mechanical energy (E_m) compared to other composite formulations. Therefore, varying the POF loading leads to extrusion and injection processing variations. Furthermore, the coupling agent significantly enhances the tensile strength, ductility, impact strength, crystallinity, stabilized torque, and E_m of the HDPE/POF composite. This improvement is due to the enhanced interfacial adhesion between the POF and the HDPE matrix with the addition of the MAPE, as supported by the Scanning Electron Microscopy (SEM) micrographs. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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29 pages, 11029 KiB

Open AccessArticle

The Use of Externally Bonded Fibre Reinforced Polymer Composites to Enhance the Seismic Resilience of Single Shear Walls: A Nonlinear Time History Assessment

by Ali Abbaszadeh and Omar Chaallal

J. Compos. Sci. 2024, 8(6), 229; https://doi.org/10.3390/jcs8060229 - 17 Jun 2024

Viewed by 691

Abstract

In medium- to high-rise buildings, single shear walls (SSWs) are often used to resist lateral force due to wind and earthquakes. They are designed to dissipate seismic energy mainly through plastic hinge zones at the base. However, they often display large post-earthquake deformations [...] Read more.

In medium- to high-rise buildings, single shear walls (SSWs) are often used to resist lateral force due to wind and earthquakes. They are designed to dissipate seismic energy mainly through plastic hinge zones at the base. However, they often display large post-earthquake deformations that can give rise to many economic and safety concerns within buildings. Hence, the primary objective of this research study is to minimize residual deformations in existing SSWs located in the Western and Eastern seismic zones of Canada, thereby enhancing their resilience and self-centering capacity. To that end, four SSWs of 20 and 15 stories, located in Vancouver and Montreal, were meticulously designed and detailed per the latest Canadian standards and codes. The study assessed the impact of three innovative strengthening schemes on the seismic response of these SSWs through 2D nonlinear time history (NLTH) analysis. All three strengthening schemes involved the application of Externally Bonded Fiber Reinforced Polymer (EB-FRP) to the shear walls. Accordingly, a total of 208 NLTH analyses were conducted to assess the effectiveness of all strengthening configurations. The findings unveiled that the most efficient technique for reducing residual drift in SSWs involved applying three layers of vertical FRP sheets to the extreme edges of the wall, full FRP wrapping the walls, and full FRP wrapping of the plastic hinge zone. Nevertheless, it is noteworthy that implementing these strengthening schemes may lead to an increase in bending moment and base shear force demands within the walls. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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18 pages, 2970 KiB

Open AccessArticle

A Study of the Moisture Absorption Characteristics of Vinyl Ester Polymer and Unidirectional Glass Fibre Vinyl Ester Laminates

by James Thomason and Georgios Xypolias

J. Compos. Sci. 2024, 8(6), 214; https://doi.org/10.3390/jcs8060214 - 7 Jun 2024

Cited by 1 | Viewed by 1016

Abstract

Vinyl esters are increasingly being used as the matrix polymer in fibre-reinforced composites for demanding large applications which experience long-term exposure to moist and wet conditions. This paper presents the results of a study of ageing due to moisture absorption in vinyl ester [...] Read more.

Vinyl esters are increasingly being used as the matrix polymer in fibre-reinforced composites for demanding large applications which experience long-term exposure to moist and wet conditions. This paper presents the results of a study of ageing due to moisture absorption in vinyl ester polymer and glass fibre–vinyl ester laminates. The moisture uptake kinetics of the two neat VE polymers, cured at different conditions, and their glass-reinforced composites has been characterised by gravimetric methods. These studies have been carried out using submersion in water at 23 °C and 50 °C and exposure to high relative humidity moisture conditions at room temperature. A dynamic mechanical analysis characterisation of the glass transition temperatures of both the aged matrix and the composite is also presented. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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12 pages, 22239 KiB

Open AccessArticle

Microstructure Evolution of Polyacrylonitrile-Based Fibers during Thermal Pre-Oxidation

by Yue Sun, Yanxiang Wang, Lanzhong Wang, Yongbo Wang, Bohan Ding, Jinghe Guo, Shichao Dai and Yuxia Wang

J. Compos. Sci. 2024, 8(6), 198; https://doi.org/10.3390/jcs8060198 - 23 May 2024

Viewed by 1144

Abstract

In this work, pre-oxidized polyacrylonitrile fibers are treated with ultrasonic etching and solution etching to produce ultra-thin sections. The evolution of the fibers’ microstructure in the pre-oxidation process is observed, and the transformation model of the microstructure of the pre-oxidized fibers is proposed. [...] Read more.

In this work, pre-oxidized polyacrylonitrile fibers are treated with ultrasonic etching and solution etching to produce ultra-thin sections. The evolution of the fibers’ microstructure in the pre-oxidation process is observed, and the transformation model of the microstructure of the pre-oxidized fibers is proposed. Scanning electron microscopy and high-resolution transmission electron microscopy were used to observe the microstructure changes of the fibers. Fourier transform infrared spectroscopy and X-ray diffraction were used to observe the chemical structure transformation and crystallization degree of the fibers in the pre-oxidation process. The results revealed that pre-oxidized fibers exhibited a smooth surface, while their interior consisted of fibrils. The longitudinal microfibrils were connected by the transverse microfibrils and amorphous regions. The fracture morphology of the fibers shifted from ductile to brittle, and the cross-section gradually became smoother. The linear molecular chain of PAN transformed into a ring structure as pre-oxidation progressed, subsequently leading to the cross-linking of this ring structure into an orderly trapezoidal configuration. The connection between the fibrils was enhanced, and the fiber structure became more compact and stable. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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19 pages, 4809 KiB

Open AccessArticle

Performance and Life Cycle Assessment of Composites Reinforced with Natural Fibers and End-of-Life Textiles

by Mina Arya, Mikael Skrifvars and Pooria Khalili

J. Compos. Sci. 2024, 8(6), 196; https://doi.org/10.3390/jcs8060196 - 22 May 2024

Cited by 2 | Viewed by 1834

Abstract

The growing need for materials that are eco-friendly and sustainable in the industrial sector has shifted focus from synthetic fossil to natural fibers, alongside the utilization of recycled polymer textiles. This research introduces a novel method for using end-of-life textiles, such as polyester [...] Read more.

The growing need for materials that are eco-friendly and sustainable in the industrial sector has shifted focus from synthetic fossil to natural fibers, alongside the utilization of recycled polymer textiles. This research introduces a novel method for using end-of-life textiles, such as polyester and polyamide fabrics, in the production of composite materials, aiming to lessen textile waste and enhance material longevity. The mechanical attributes of flax fabric (FF), flax–recycled polyamide fabric (F/RPA), and flax–recycled polyester fabric (F/RPES) composite laminates are assessed through tensile, flexural, interlaminar shear, and Charpy impact tests. The study revealed that the addition of end-of-life synthetic fibers improves tensile strength, while the trend in modulus values suggests that flax provides a high degree of stiffness to the composites, which is moderated by the addition of synthetic fibers. This effect is consistent across both tensile and flexural testing, although the impact on stiffness is more significant in bending. The inclusion of polyester fibers in the composite laminate resulted in significant enhancements, with an 11.1% increase in interlaminar shear maximum force, a 17.4% improvement in interlaminar shear strength, and a 67.1% rise in un-notch impact energy, compared to composites made with only flax fiber (FF). The microscopic examination uncovered the internal structure and demonstrated a clear, strong bond between the polyester and polyamide fiber layers with the flax fibers. Additionally, the life cycle assessment revealed that the F/RPES composite had less environmental impact than FF and F/RPA in all 18 categories analyzed. This indicates that the environmental footprint of producing F/RPES is smaller than that of both FF and F/RPA. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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18 pages, 4892 KiB

Open AccessArticle

Analytical and Experimental Behaviour of GFRP-Reinforced Concrete Columns under Fire Loading

by Ana Almerich-Chulia, Pedro Martin-Concepcion, Jesica Moreno-Puchalt and Jose Miguel Molines-Cano

J. Compos. Sci. 2024, 8(5), 187; https://doi.org/10.3390/jcs8050187 - 16 May 2024

Viewed by 841

Abstract

Fire engineering endeavours to mitigate injury or the loss of life in the event of a fire. This is achieved primarily through fire prevention, containment, and extinguishment measures. Should prevention fail, the structural integrity of buildings, coupled with effective evacuation strategies, becomes paramount. [...] Read more.

Fire engineering endeavours to mitigate injury or the loss of life in the event of a fire. This is achieved primarily through fire prevention, containment, and extinguishment measures. Should prevention fail, the structural integrity of buildings, coupled with effective evacuation strategies, becomes paramount. While glass fibre-reinforced polymer (GFRP) materials have demonstrated efficacy in reinforcing concrete elements, their performance under fire conditions, notably in comparison to steel, necessitates a deeper understanding for structural applications. This study experimentally and numerically investigates the fire performance of GFRP-reinforced concrete (RC) columns subjected to only fire load without additional external loads. The research aims to ascertain the fire resistance based on the thickness of the concrete coating and the ultimate tensile strength of GFRP rebars after 90 min of fire exposure. Four GFRP-RC columns were subjected to a standardized fire curve on all sides in the experimental program. In the analytical program, a theoretical model was developed using the heat transfer module of the COMSOL software. The results of both analyses were very close, indicating the reliability of the procedure used. Based on the findings, recommendations regarding the fire resistance of GFRP-RC columns were formulated for structural applications. Results from this research provide the civil engineering community with data that will help them continue using FRP materials as internal reinforcement for concrete. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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18 pages, 5616 KiB

Open AccessArticle

Punching Shear of FRP-RC Slab–Column Connections: A Comprehensive Database

by Yazan Almomani, Roaa Alawadi, Ahmad Tarawneh, Abdullah Alghossoon and Ahmad Aldiabat

J. Compos. Sci. 2024, 8(4), 145; https://doi.org/10.3390/jcs8040145 - 12 Apr 2024

Viewed by 1619

Abstract

Several design standards have been developed in the last two decades to estimate the punching capacity of two-way reinforced concrete (RC) slabs reinforced with fiber-reinforced polymer (FRP) reinforcement. FRP-RC design standards include the recently published ACI 440.11-22, CSA/S806-12, and JSCE-2007. These models are [...] Read more.

Several design standards have been developed in the last two decades to estimate the punching capacity of two-way reinforced concrete (RC) slabs reinforced with fiber-reinforced polymer (FRP) reinforcement. FRP-RC design standards include the recently published ACI 440.11-22, CSA/S806-12, and JSCE-2007. These models are either based on empirical data or semi-empirical methods and calibrated using different databases. Additionally, these standards do not have provisions for connections with shear reinforcement. Therefore, a reliable worldwide database for developing and assessing the applicability of such provisions with test results is vital. This study presents a worldwide and up-to-date database for punching shear of FRP-RC slabs. The database includes 197 tested connections, comprising interior and edge connections, with and without shear reinforcement, and a wide range of materials and cross-sectional properties. The database was used to evaluate the accuracy of the mentioned standards in predicting the punching shear capacity. For connections without shear reinforcement, it was determined that the three design standards yielded similar performance with different conservatism levels. ACI 440.11-22 yielded the most conservative results, with average V_exp/V_pred ratios of 2.04 compared to 1.28 and 1.3 for other models. For connection with shear reinforcement, specimens with E_vf> 100 GPa resulted in V_exp/V_pred ratios less than 1.0 for ACI and CSA standards. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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15 pages, 5015 KiB

Open AccessArticle

Static and Dynamic Mechanical Behavior of Carbon Fiber Reinforced Plastic (CFRP) Single-Lap Shear Joints Joule-Bonded with Conductive Epoxy Nanocomposites

by Yuheng Huang, Ian A. Kinloch and Cristina Vallés

J. Compos. Sci. 2024, 8(3), 112; https://doi.org/10.3390/jcs8030112 - 21 Mar 2024

Cited by 2 | Viewed by 1509

Abstract

The potential of electrically conductive graphene nanoplatelets (GNPs)/epoxy, multi-walled carbon nanotubes (MWNCTs)/epoxy and hybrid GNPs-MWCNTs/epoxy nanocomposites as adhesives for out-of-autoclave (OoA) and in-the-field CFRP repair via Joule heat curing was investigated. Scanning electron microscopy revealed a good dispersion of the nanoparticles in the [...] Read more.

The potential of electrically conductive graphene nanoplatelets (GNPs)/epoxy, multi-walled carbon nanotubes (MWNCTs)/epoxy and hybrid GNPs-MWCNTs/epoxy nanocomposites as adhesives for out-of-autoclave (OoA) and in-the-field CFRP repair via Joule heat curing was investigated. Scanning electron microscopy revealed a good dispersion of the nanoparticles in the matrix in all the nanocomposite adhesives above their percolation thresholds, which led to a homogeneous distribution of the heat generated during Joule CFRP repair. The joints bonded with neat epoxy and the nanocomposites showed similar lap shear strengths, with the addition of nanoparticles enhancing the fatigue performance of the adhesively bonded joints relative to when neat epoxy was used as an adhesive and oven-cured. The interfacial and cohesive failure mechanisms were found to coexist in all the cases, with an increasing dominance of the cohesive when nanofillers were embedded into the adhesive. No effect of the specific type of nanofiller incorporated into the epoxy as the conductive component was observed on the mechanical performance of the bonded joints, with the adhesives containing MWCNTs showing similar results to those filled with GNPs at considerably lower loadings due to their lower percolation thresholds. The independence of the properties regardless of the curing method highlights the promise of these Joule-cured adhesives for industrial applications. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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13 pages, 3340 KiB

Open AccessArticle

Promotive Effect of Non-Woven Polylactide/Natural Rubber Composites on Growth and Biochemical Constituents of Purple Basil (Ocimum basilicum L.)

by Yulia V. Tertyshnaya, Anastasia N. Skorokhodova, Anastasia Yu. Anpilova and Anatoliy A. Olkhov

J. Compos. Sci. 2024, 8(3), 102; https://doi.org/10.3390/jcs8030102 - 13 Mar 2024

Cited by 1 | Viewed by 1368

Abstract

Presently, modern trends focused on eco-friendly “green” technologies are increasing the widespread use of biodegradable polymers and polymer composites in agricultural production. In this work, non-woven materials, polylactide/natural rubber (PLA/NR) composites with a different natural rubber content, were used as substrates for growing [...] Read more.

Presently, modern trends focused on eco-friendly “green” technologies are increasing the widespread use of biodegradable polymers and polymer composites in agricultural production. In this work, non-woven materials, polylactide/natural rubber (PLA/NR) composites with a different natural rubber content, were used as substrates for growing purple basil (Ocimum basilicum L.) in the multisoil compound in a phytochamber. It was shown that non-woven PLA/NR fabrics stimulate the growth and development of purple basil plants during the growing season. Compared to the control sample, the germination and biometric indicators of basil were higher when using PLA/NR substrates. The production of basil’s photosynthetic pigments also increased. While using PLA/NR fabrics with a rubber content of 10 and 15 wt.%, the number of chlorophyll a was enhanced by 1.8–2.2 times and chlorophyll b by 2.5–3.2 times. In the process of the hydrolytic and enzymatic degradation of the polymer matrix, organic compounds are formed that provide additional nutrition for basil plants. Non-woven PLA/NR composites became brittle after the experiment. The PLA/NR morphology, structure, and rheological properties changed, which indicates the course of biodegradation processes in the polymer matrix. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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20 pages, 10216 KiB

Open AccessArticle

Development of Sugarcane Bagasse Ash Blended Cementitious Composites Reinforced with Carbon Nanotubes and Polypropylene Fibers

by Muhammad Ayyan Iqbal, Umbreen Us Sahar, Alireza Bahrami, Noor Yaseen and Iffat Siddique

J. Compos. Sci. 2024, 8(3), 94; https://doi.org/10.3390/jcs8030094 - 4 Mar 2024

Cited by 2 | Viewed by 2344

Abstract

Cement-based composites, as primary construction materials, have undergone significant advancements over the years, yet researchers still face challenges in terms of their durability and impact on the environment. The goal of this research is to develop environmentally friendly cementitious composites blended with sugarcane [...] Read more.

Cement-based composites, as primary construction materials, have undergone significant advancements over the years, yet researchers still face challenges in terms of their durability and impact on the environment. The goal of this research is to develop environmentally friendly cementitious composites blended with sugarcane bagasse ash (SCBA) and reinforce them with multi-walled carbon nanotubes and polypropylene (PP) fibers. Because of the high cost associated with carbon nanotubes (CNTs) and PP fibers, as well as CO₂ emission, which affect the economic and environmental aspects of this field, an agricultural waste such as SCBA was introduced in the current study that is both economically and environmentally viable. For this purpose, five mixes were designed by varying the CNTs content whilst keeping the PP fibers and SCBA contents constant at 1.5% and 15% by weight of the binder (ordinary Portland cement + SCBA), respectively. The developed blends were tested for various mechanical and durability properties, i.e., compressive strength, flexural strength, impact strength, water absorption, and ultrasonic pulse velocity. Moreover, the microstructures of the newly developed low-carbon SCBA-based composites reinforced with PP fibers and CNTs were studied through scanning electron microscopy and energy dispersive spectroscopy. The results showed that the developed blends incorporating 15% SCBA, 1.5% PP fibers, and 0.08% CNTs, by weight of the binder, demonstrated the compressive, flexural, and impact strengths as 15.30 MPa, 0.98 MPa, and 0.11 MPa, respectively. The investigated blends proved to be cost-effective and environmentally beneficial, rendering them suitable for utilization in general construction and maintenance works. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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12 pages, 1565 KiB

Open AccessArticle

Modification of Talc and Mechanical Properties of Polypropylene-Modified Talc Composite Drawn Fibers

by Costas Tsioptsias, Konstantinos Leontiadis, Xanthi Ntampou and Ioannis Tsivintzelis

J. Compos. Sci. 2024, 8(3), 91; https://doi.org/10.3390/jcs8030091 - 3 Mar 2024

Cited by 1 | Viewed by 1667

Abstract

A large amount of the polypropylene (PP) produced worldwide is used in the form of fibers. In this work, a new modification route for talc and PP is investigated, which is based on the in situ polymerization of a silane–siloxane monomer mixture on [...] Read more.

A large amount of the polypropylene (PP) produced worldwide is used in the form of fibers. In this work, a new modification route for talc and PP is investigated, which is based on the in situ polymerization of a silane–siloxane monomer mixture on the surface of talc particles or PP pellets, respectively. The obtained modified talc and PP samples were used for the development of PP-talc composite drawn fibers. Tensile tests, thermogravimetry (TGA), and X-ray diffraction (XRD) were used for the characterization of the materials. It was observed that such a modification procedure resulted in the exfoliation of some talc particles. Enhanced tensile strength was observed for composite drawn fibers of a low talc content (1% with respect to PP) and a low modifier content (2% with respect to talc), while co-aggregation of talc and silicone may occur at high silicone and talc contents, resulting in the inferior mechanical performance of the corresponding composites. It was concluded that the produced silicone polymer simultaneously acts as a modifier, antioxidant, and compatibilizer. The proposed modification route is promising and should be further optimized. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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14 pages, 9395 KiB

Open AccessArticle

Development of Highly Ultraviolet-Protective Polypropylene/TiO₂ Nonwoven Fiber

by Md. Abu Hanif, Hyokyeong Shin, Danbi Chun, Hong Gun Kim, Lee Ku Kwac, Sang-Won Han, Sung-Soo Kang and Young Soon Kim

J. Compos. Sci. 2024, 8(3), 86; https://doi.org/10.3390/jcs8030086 - 25 Feb 2024

Cited by 3 | Viewed by 1855

Abstract

In recent decades, there has been a rise in public consciousness of the adverse effects of expanded skin contact with sunlight, particularly the ultraviolet (UV) spectrum. UV radiation causes serious health problems like skin cancer, early aging, erythema, pigmentation, etc., due to contact [...] Read more.

In recent decades, there has been a rise in public consciousness of the adverse effects of expanded skin contact with sunlight, particularly the ultraviolet (UV) spectrum. UV radiation causes serious health problems like skin cancer, early aging, erythema, pigmentation, etc., due to contact with the skin. Therefore, the highly efficient UV-protection materials were manufactured using polypropylene and TiO₂ (PPTO) through cost-effective and easy methods. The designated 7.5 PPTO and 15 PPTO were prepared, varying the amount of TiO₂, as well as without using TiO₂ (PPNF), which was also manufactured as a control material. All the as-synthesized nonwoven fibers were carefully characterized employing a variety of microscopic and spectroscopic methods, such as X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, and contact angle measurements. In conclusion, 15 PPTO showed the highest UV-protection ability (87.5%) compared to 7.5 PPTO and PPNF. In addition, 15 PPTO exhibited 1.76 and 1.32 times higher protection than 7.5 PPTO and PPNF, respectively, when exposed to UB-B radiation. The enhanced activity may be due to the amount of TiO₂ because TiO₂ increased the product’s absorption and reflection capability. Overall, the PPTO nonwoven fibers can be applied to block harmful UV radiation. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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14 pages, 5877 KiB

Open AccessArticle

Synergistic Enhancement of the Mechanical Properties of Epoxy-Based Coir Fiber Composites through Alkaline Treatment and Nanoclay Reinforcement

by Puneethraj Hebbalu Puttaswamygowda, Sathyashankara Sharma, Achutha Kini Ullal and Manjunath Shettar

J. Compos. Sci. 2024, 8(2), 66; https://doi.org/10.3390/jcs8020066 - 8 Feb 2024

Cited by 7 | Viewed by 1716

Abstract

This study explores the synergistic effects of incorporating coir fibers and nanoclay into epoxy resin composites. Coir, a renewable and cost-effective natural fiber, undergoes an alkaline treatment to influence its ability to form strong interfacial bonding with the epoxy matrix. To further enhance [...] Read more.

This study explores the synergistic effects of incorporating coir fibers and nanoclay into epoxy resin composites. Coir, a renewable and cost-effective natural fiber, undergoes an alkaline treatment to influence its ability to form strong interfacial bonding with the epoxy matrix. To further enhance the mechanical properties of the composite, montmorillonite nanoclay, surface-modified with aminopropyltriethoxysilane and octadecyl amine, is introduced. The research investigates different combinations of coir fiber content (20, 30, and 40 wt%) and nanoclay loading (0, 2, and 4 wt%) with epoxy resin. The composites are fabricated through an open molding process, and the mechanical properties are evaluated using tensile and flexural tests according to the ASTM D638 and D7264 standards, respectively. The tensile and flexural strengths of the 40 wt% coir fiber-reinforced epoxy composite are found to be 77.99 MPa and 136.13 MPa, which are 44% and 23% greater than pure epoxy, respectively. Furthermore, the strengths displayed a 23% improvement in tensile strength with 4 wt% and a 31.4% improvement in flexural strength with 2 wt% nanoclay as additional reinforcement. Scanning electron microscopy is employed for fractographic analysis of the fractured specimens from the tensile test. The study underscores the importance of understanding the interplay between natural fibers, nanoclay, and epoxy resin for optimizing the composite’s performance in real-world applications. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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20 pages, 9484 KiB

Open AccessArticle

Self-Unfolding Properties of Smart Grid-Reinforced Membrane Origami

by Haotian Hu, Zhenmeng Xia, Qiang Tao, Zixin Ye, Kaifeng Yuan and Leying Song

J. Compos. Sci. 2024, 8(2), 64; https://doi.org/10.3390/jcs8020064 - 7 Feb 2024

Viewed by 1873

Abstract

Origami-based membrane structures have shown great potential to revolutionize the construction of deployable and lightweight space structures in the future. However, the efficient unfolding mechanism puts forward major challenges to the practical realization of space-deployable structures. Here, a smart grid-reinforced membrane origami (SGRMO) [...] Read more.

Origami-based membrane structures have shown great potential to revolutionize the construction of deployable and lightweight space structures in the future. However, the efficient unfolding mechanism puts forward major challenges to the practical realization of space-deployable structures. Here, a smart grid-reinforced membrane origami (SGRMO) is presented. The unfolding action hinges upon the application of forces facilitated by shape memory polymer composites (SMPCs). Subsequent locking action ensues through the restoration of the initial rigidity, accomplished via cooling mechanisms. This novel structure achieves the required lightweight and functionality by employing the grid design concept and effectively reduces the decline in unfolding extent caused by irreversible plastic deformation at the crease. Its recovery properties, including unfolding angle, distance, and surface precision, are experimentally and analytically investigated under different conditions. The results indicate that the structure can be reliably unfolded into the predefined shapes. In the case of Miura-SGRMO, the optimal surface precision is attained when the angle-ψ registers at 30°. The results of this study are expected to serve as the design of ultra-large flexible solar arrays and deployable antenna structures. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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14 pages, 8618 KiB

Open AccessArticle

Transferability of the Structure–Property Relationships from Laser-Pretreated Metal–Polymer Joints to Aluminum–CFRP Hybrid Joints

by Jonathan Freund, Isabel Lützenkirchen, Miriam Löbbecke, Alexander Delp, Frank Walther, Shuang Wu, Thomas Tröster and Jan Haubrich

J. Compos. Sci. 2023, 7(10), 427; https://doi.org/10.3390/jcs7100427 - 12 Oct 2023

Cited by 2 | Viewed by 1623

Abstract

The transferability of structure–property relationships for laser-pretreated metal adhesive joints to laser-pretreated metal–carbon-fiber-reinforced plastic (CFRP) bonds was investigated. Single-lap shear tests were performed on hybrid AW 6082-T6–CFRP specimens pretreated with the same pulsed laser surface parameter sets on the metal surface as previously [...] Read more.

The transferability of structure–property relationships for laser-pretreated metal adhesive joints to laser-pretreated metal–carbon-fiber-reinforced plastic (CFRP) bonds was investigated. Single-lap shear tests were performed on hybrid AW 6082-T6–CFRP specimens pretreated with the same pulsed laser surface parameter sets on the metal surface as previously tested, AW 6082-T6–E320 metal adhesive joints. The fracture surfaces were characterized to determine the type of failure and elucidate differences and commonalities in the link between surface structures and single-lap shear strengths. Digital image analyses of the hybrid specimens’ fractured surfaces were used to quantify remaining CFRP fragments on the metallic joint side. The results indicate that high surface enlargements and the presence of undercut structures lead to single-lap shear strengths exceeding 40 MPa and 35 MPa for unaged and aged hybrid specimens, respectively. Whereas for the metal–polymer joints, the trend from high strength to weakly bonded specimens is largely continuous with the degree of surface structuring, hybrid metal–CFRP joints exhibit a drastic drop in joint performance after aging if the laser-generated surface structures are less pronounced with low surface enlargements and crater depths. Surface features and hydrothermal aging determine whether the specimens fail cohesively or adhesively. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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18 pages, 4720 KiB

Open AccessArticle

Potential Use of COVID-19 Surgical Masks and Polyethylene Plastics in Developing Sustainable Concrete

by Suvash Chandra Paul, Md. Ahosun Habib Santo, Sowmik Ahmed Nahid, Asifur Rahman Majumder, Md. Fahim Al Mamun, Md Abdul Basit and Adewumi John Babafemi

J. Compos. Sci. 2023, 7(9), 402; https://doi.org/10.3390/jcs7090402 - 20 Sep 2023

Cited by 2 | Viewed by 2154

Abstract

Managing disposable waste surgical face masks and plastic made from polyethylene (PE) resin is a real challenge. Thus, these are considered a great threat to the environment. Generally, surgical face masks are made of microplastic made of polypropylene materials. Both polypropylene and PE [...] Read more.

Managing disposable waste surgical face masks and plastic made from polyethylene (PE) resin is a real challenge. Thus, these are considered a great threat to the environment. Generally, surgical face masks are made of microplastic made of polypropylene materials. Both polypropylene and PE are not easily decomposable in the soil. Consequently, the presence of these waste materials can have detrimental effects on terrestrial and aquatic ecosystems, exacerbating the ongoing crisis faced by the animal kingdom and the broader biosphere. Hence, it is imperative to identify alternate and efficient methods for waste management. Given its significant economic importance, the construction industry holds a prominent position among many industries globally. Consequently, waste masks within the construction sector might assume a crucial role in mitigating plastic pollution. Concrete, one of the most widely used construction materials, is being adapted with various waste materials as the partial or complete substitutes for natural constituents, such as cement and aggregates. This study focused on using different percentages of used COVID-19 surgical masks in fiber form and PE as partial replacements of natural coarse aggregates in producing sustainable concrete. Mask fibers were used in concrete production at percentages of 0%, 0.5%, 1%, 1.5%, and 2% of the total volume of concrete. Similarly, PE aggregates replaced the coarse aggregates by volume at 0%, 5%, 10%, and 15% in concrete. The results showed that the strength of concrete reduced as the percentages of mask fiber and PE aggregates increased. However, the strength and crack-bridging capability of mask concrete are still acceptable for some structural and non-structural applications. The results obtained from this research could also help engineers to design sustainable concrete materials with mask fibers. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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21 pages, 9829 KiB

Open AccessArticle

Ethiopian Bamboo Fiber Aging Process and Reinforcement: Advancing Mechanical Properties of Bamboo Fiber-Epoxy Composites for Automobile Applications

by Yalew Dessalegn, Balkeshwar Singh, Barisso Bino Safayo, Mohammed Jameel, Nazia Hossain, Ahmad Rashedi and Gulam Mohammed Sayeed Ahmed

J. Compos. Sci. 2023, 7(9), 375; https://doi.org/10.3390/jcs7090375 - 7 Sep 2023

Cited by 2 | Viewed by 1384

Abstract

The purpose of this paper is to evaluate the properties of Ethiopian bamboo fibre polymer composites as headliners in the automobile industry. Bamboo fibres are developed using the roll milling technique, and bamboo fibre epoxy composites (BFEPCS) are developed using a compression mould [...] Read more.

The purpose of this paper is to evaluate the properties of Ethiopian bamboo fibre polymer composites as headliners in the automobile industry. Bamboo fibres are developed using the roll milling technique, and bamboo fibre epoxy composites (BFEPCS) are developed using a compression mould and a hot press machine. The mechanical properties are measured based on the recommended procedure of the ASTM. In total, 40% of the volume fraction of fibres is used to produce polymer composites. An accurate evaluation of its mechanical properties is thus critical for predicting its behaviour during a vehicle’s interior impact assessment. Conventional headliner materials are heavier, non-biodegradable, expensive, and non-sustainable during processing compared to the currently researched materials. Three representatives of bamboo plants are harvested in three regions of bamboo species, three groups of ages, and two harvesting months. Two-year-old bamboo fibres have the highest mechanical properties of all ages, and November has a higher mechanical properties compared to February. Inji-bara and Kom-bolcha have the highest and lowest mechanical properties, respectively. BFEPCs have high mechanical properties compared to BFPPCs. The mechanical properties of the current research findings have higher measured values compared to Jute felt PU, CFPU, GFMPU, BFPP, BFEP, PP foam, and TPU. The flexural strength of BFPCs has higher properties compared to their tensile strength. Ethiopian bamboo fibres and their polymer composites have the best mechanical properties for the composite industry, which is used for headliner materials in the automobile industry, compared to conventional headliner materials. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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19 pages, 26110 KiB

Open AccessArticle

Experimental Study on Low-Velocity Impact Performance of GFRP Trapezoidal Corrugated Sandwich Structures

by Yunfei Deng, Yao Deng, Wenquan Liu, Shitong Zhang and Kuo Tian

J. Compos. Sci. 2023, 7(7), 272; https://doi.org/10.3390/jcs7070272 - 30 Jun 2023

Cited by 1 | Viewed by 1408

Abstract

Glass fiber trapezoidal corrugated sandwich structures are composed of trapezoidal cores and glass fiber-reinforced polymer (GFRP) panels. A series of low-velocity impact tests were conducted to investigate the impact resistance performance, considering the effects of impact position, impactor shape, and impactor diameter on [...] Read more.

Glass fiber trapezoidal corrugated sandwich structures are composed of trapezoidal cores and glass fiber-reinforced polymer (GFRP) panels. A series of low-velocity impact tests were conducted to investigate the impact resistance performance, considering the effects of impact position, impactor shape, and impactor diameter on the damage mechanism of sandwich structures. When the impactor shape and impact energy remain constant, the maximum impact load at the node impact point is higher than at the base, while the displacement of impact at the base is significantly higher than that at the node. Secondly, when the impactor diameter and energy of the impactor are the same, the hemispherical impactor requires less penetration energy to impact the sandwich structure compared to the flat impactor. Comparing the shape of the impactor, it is found that the smaller the contact surface of the impactor, the more concentrated the stress, and the lower the required penetration energy. Finally, when the impactor shape and impact energy are the same, as the diameter of impactor increases, the damage expansion during impacting on the sandwich structure becomes more sufficient, resulting in decreased impact displacement and smaller impact damage caused to the sandwich structure. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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Review

Jump to: Research

28 pages, 5591 KiB

Open AccessReview

Keratinous Natural Fibres as Sustainable Flame Retardants and Reinforcements in Polymer Composites

by Avishek Mishra, Nam Kyeun Kim and Debes Bhattacharyya

J. Compos. Sci. 2024, 8(6), 230; https://doi.org/10.3390/jcs8060230 - 17 Jun 2024

Viewed by 1186

Abstract

Natural fibres have been used as fibre reinforcements in composites as they offer eco-friendly and economic advantages, but their susceptibility to deterioration when exposed to heat and flames has limited their practical application in fibre-reinforced polymeric composites. Fire-reaction properties have been explored in [...] Read more.

Natural fibres have been used as fibre reinforcements in composites as they offer eco-friendly and economic advantages, but their susceptibility to deterioration when exposed to heat and flames has limited their practical application in fibre-reinforced polymeric composites. Fire-reaction properties have been explored in reasonable detail for plant fibres, but a gap exists in the understanding of animal fibre-reinforced composites. Understanding the thermal and fire reactions of these keratin-rich animal fibres is crucial for material selection and advancing composite product development. The current paper critically discusses the existing research landscape and suggests future research directions. The use of keratinous fibres in composites can definitely improve their thermal stability and fire performance, but it also appears to adversely affect the composite’s mechanical performance. The main part of this paper focuses on the flame-retardant treatment of keratinous fibres and polymer composites, and their behaviour under fire conditions. The final part of this paper includes a brief look at the environmental impact of the treatment methods; the overall processing of keratinous fibre-reinforced composites is also presented to gain further insight. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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19 pages, 1561 KiB

Open AccessReview

A Review on the Electrospinning of Polymer Nanofibers and Its Biomedical Applications

by Balu Alagar Venmathi Maran, Sivakamavalli Jeyachandran and Masanari Kimura

J. Compos. Sci. 2024, 8(1), 32; https://doi.org/10.3390/jcs8010032 - 15 Jan 2024

Cited by 13 | Viewed by 5668

Abstract

Polymeric nanofibers have emerged as a captivating medium for crafting structures with biomedical applications. Spinning methods have garnered substantial attention in the context of medical applications and neural tissue engineering, ultimately leading to the production of polymer fibers. In comparison with polymer microfibers, [...] Read more.

Polymeric nanofibers have emerged as a captivating medium for crafting structures with biomedical applications. Spinning methods have garnered substantial attention in the context of medical applications and neural tissue engineering, ultimately leading to the production of polymer fibers. In comparison with polymer microfibers, polymer nanofibers boasting nanometer-scale diameters offer significantly larger surface areas, facilitating enhanced surface functionalization. Consequently, polymer nanofiber mats are presently undergoing rigorous evaluation for a myriad of applications, including filters, scaffolds for tissue engineering, protective equipment, reinforcement in composite materials, and sensors. This review offers an exhaustive overview of the latest advancements in polymer nanofiber processing and characterization. Additionally, it engages in a discourse regarding research challenges, forthcoming developments in polymer nanofiber production, and diverse polymer types and its applications. Electrospinning has been used to convert a broad range of polymers into nanoparticle nanofibers, and it may be the only approach with significant potential for industrial manufacturing. The basics of these spinning techniques, highlighting the biomedical uses as well as nanostructured fibers for drug delivery, disease modeling, regenerative medicine, tissue engineering, and bio-sensing have been explored. Full article

(This article belongs to the Special Issue Polymer Composites and Fibers, Volume II)

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