Journal of Thermoplastic Composite Materials

Natural fiber-reinforced polystyrene composites (NFRPCs) present a sustainable alternative to conventional composites, offering a balance between environmental benefits and mechanical performance. Their application in sectors such as automotive and construction is gaining attention due to their lightweight nature, cost-effectiveness, and reduced carbon footprint. However, challenges such as weak fiber-matrix adhesion and the thermal sensitivity of natural fibers necessitate surface treatments and compatibilizers to improve composite performance. This review examines the influence of fiber treatments, including alkali, silane, benzoylation, and maleic anhydride, on interfacial bonding and mechanical integrity. Comparative analyses of untreated and treated fiber composites demonstrate significant enhancements in tensile and flexural properties, confirming the effectiveness of chemical modifications. A case study on automotive interiors integrates mechanical property evaluation by the Mori-Tanaka method, thermal performance assessment using the finite element method, and life cycle analysis, providing a comprehensive evaluation of NFRPCs’ industrial applicability. Results indicate that optimized NFRPCs offer viable solutions for lightweight, durable, and eco-friendly materials, supporting circular economy initiatives. The findings reinforce their potential for replacing synthetic composites in targeted applications while addressing economic and environmental considerations.

Long fiber thermoplastic (LFT) composites have gained significant attention in various industries due to their desirable properties, including ease of processing, recyclability, superior strength, and corrosion resistance. Glass fiber (GF) is commonly used as a reinforcing material in LFT composites, given its low cost and excellent mechanical properties. However, there are challenges associated with the existing manufacturing processes, such as fiber attrition and limitations in achieving anisotropic properties. In this study, the overmolding of glass fiber-reinforced polyphenylene sulfide long fiber thermoplastic (G-LFT) and unidirectional continuous carbon fiber/polyphenylene sulfide tape (CF-Tape) using an Automated Tape Placement (ATP) robotic system has been investigated. The aim is to explore the potential of ATP for improving the mechanical properties of LFT composites. The results reveal that the overmolding process using CF-Tape on G-LFT leads to significant enhancements in mechanical performance. A 129% increase in tensile strength and a 192% improvement in flexural strength were observed compared to the G-LFT baseline. The bond strength at the interface was evaluated through flatwise tensile testing, which resulted in partial failure within the CF-Tape and a measured bond strength of 7.52 MPa ± 0.34. Thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) were conducted to analyze the thermal behavior of the parts. The crystallinity was measured using DSC data, and a value of 33.4% was obtained. Low-velocity impact testing has been conducted to understand the dynamic behavior of G-LFT and G-LFT/CF-Tape. The impact energy absorbed was found to be similar in both cases. A numerical model was used to reduce the number of experiments. It was found that the flexural strength would improved by 60% by adding five layers of CF-Tape. In summary, this research contributes to expanding the knowledge of overmolding techniques and highlights the potential of ATP-based overmolding for for enhancing the localized strength and easily applied to intricate geometries.

Graphical Abstract

Due to their high strength and exceptional thermal resistance, boron nitride (BN) nanostructures are a promising new type of reinforcement for medical applications. Among these, cubic BN (c-BN) nanoparticles are crystalline-shaped structural, combining extremely high hardness and thermal stability, which make them highly effective reinforcements in polymers. Their incorporation enhances material performance by increasing density, load-bearing capacity, and wear resistance. This study examines the influences of c-BN nanoparticle addition on the mechanical and wear characteristics of PMMA/c-BN biocomposites. c-BN nanoparticles (NPs) were added to the polymer matrix at different concentrations of 0, 0.5, 1, 2, 3, and 5 wt%. Measurements of bulk density, Vickers microhardness, ultimate compressive stress, yield stress, and wear resistance revealed that the properties of the fabricated composites were significantly improved by the increased concentration of c-BN nanoparticles in the matrix. Notably, the biocomposites containing a 5 wt% c-BN exhibited the highest bulk density, hardness values, and surface roughness of 1.221 ± 0.002 g/cm³, 79.5 ± 1.6 HV, and 125.52 µm, respectively; while the porosity decreased to 0.16% compared to other produced composites. In particular, the biocomposite produced at 3 wt% c-BN displayed the highest ultimate compressive stress, and yield stress: 215 ± 6.17 MPa, and 101.1 ± 2.2 MPa, respectively, with improvements of 99.07%, and 27.85% compared with the PMMA matrix. Additionally, the wear track profiles also showed improved wear resistance; this was confirmed by 3D surface roughness topography and experimental results for SEM images of worn surfaces. Due to their superior mechanical and wear resistance, PMMA biocomposites with c-BN NPs make excellent secondary reinforcement for a variety of medical applications, including dental prostheses.

The growing emphasis on sustainability has driven research toward the recycling of polypropylene (PP) waste reinforced with natural fillers. This study investigates the development of rice husk–reinforced recycled polypropylene (RH-PP) composites for assistive applications using a cost-effective and scalable injection molding process. Nine composite formulations were developed by varying RH content (10–30 wt%) and particle sizes (125–500 µm), and their mechanical, thermal, chemical, and morphological properties were characterized. The optimal composite formulation (80 wt% PP, 20 wt% RH, 125 µm) exhibited enhanced performance with compressive strength of 57.3 MPa, bending strength of 45.3 MPa, tensile strength of 49.2 MPa, and impact energy of 4.2 KJ/mm². Thermogravimetric analysis (TGA) showed a maximum degradation temperature of 407.6°C, while differential scanning calorimetry (DSC) revealed crystallinity values ranging from 38.8% to 40.7%. Scanning electron microscopy (SEM) confirmed improved interfacial adhesion and uniform filler dispersion. The integration of Grey Relational Analysis (GRA) enabled multi-response optimization, identifying the most influential parameters. The findings demonstrate that RH-PP composites offer a sustainable and mechanically robust alternative to virgin PP for use in orthotic and prosthetic applications.

This study presents the synthesis of zinc ferrite (ZnFe₂O₄) nanoparticles via a simple green route and their reinforcement in polyvinyl chloride (PVC) to fabricate nanocomposite films. The structural, optical, and thermal properties of PVC/ZnFe₂O₄ nanocomposites were examined at varying nanoparticle concentrations (1 wt.%, 3 wt.%, and 5 wt.%). X-ray diffraction confirmed the polycrystalline nature of the films, while FESEM analysis demonstrated a uniform dispersion of ZnFe₂O₄ nanoparticles within the PVC matrix. Optical studies indicated enhanced UV absorption with increasing ZnFe₂O₄ content, accompanied by a significant reduction in bandgap energy from 3.0 eV to 1.2 eV. Photoluminescence analysis revealed a decrease in electron-hole recombination, suggesting improved charge separation. Wettability studies showed an increase in the water contact angle, indicating enhanced hydrophilicity in the modified films. Thermal analysis demonstrated that the incorporation of ZnFe₂O₄ nanoparticles accelerated PVC degradation due to their catalytic activity while also increasing char residue formation. These findings highlight the potential of PVC/ZnFe₂O₄ nanocomposites in applications requiring tailored degradation behavior and enhanced optical performance.

Joints are important connections for realizing long-distance transportation via composite pipes and have been widely used in oil and gas transportation. A joint is also a weak link influencing the safe operation of pipelines. In this work, a three-dimensional assembly model of glass fiber-reinforced plastic composite pipes and metal buckling joints was constructed and analyzed using the finite element method (FEM) to investigate the influence of the buckling amount and structural parameters of joints on the sealing performance of joints. The results showed that the sealing performance of the joint gradually improved with increasing buckling. When a larger amount of buckling occurs, the RTP will undergo excessive plastic deformation, and the sealing performance of the joint decreases. The optimized structural parameters of the metal joint are a buckling amount of 5 mm, several serrations of 13, a tooth height of 3 mm, and two serration angles of 55° and 25°. When using optimized parameters and extreme working conditions (the internal pressure is 19.2 MPa), the maximum stress of the innermost fiber exceeds the tensile strength with a higher risk of failure. However, the optimized design of the joint can meet the requirement of safe operation at a standard pressure of 6.4 MPa.

In the present research, the effect of shear on the crystallization behavior of polypropylene (PP) nanocomposites loaded with carbon nanotube (CNT) and carbon black (CB) has been evaluated. Rheological properties, crystallization under shear, and electrical conductivity under shear of the bi-filler PP/CNT/CB nanocomposites have been evaluated and compared with those of the mono-filler PP/CNT and PP/CB nanocomposites. According to the rheological analyses, in the comparison between mono-filler and bi-filler nanocomposites with the same filler content, the storage modulus, complex viscosity, non-terminal behavior, and solid-like behavior of the bi-filler nanocomposites were higher than those of the mono-filler nanocomposites. Whereas, the storage modulus and complex viscosity of the bi-filler nanocomposites with half filler content were intermediate of the mono-filler nanocomposites. The zero viscosity of the bi-filler nanocomposite with the same filler content was about 6 times that of the mono-filler nanocomposites. Whereas, the zero viscosity values of the bi-filler nanocomposites with half filler content were 1.1-3.4 times those of the CB-loaded and 0.3-0.9 those of the CNT-loaded nanocomposites. According to the non-isothermal crystallization test, in the comparison between mono-filler and bi-filler nanocomposites with the same filler content, the crystallization temperature (T_c) of the bi-filler nanocomposites was 2.7 °C–3.5 °C higher than that of the mono-filler nanocomposites. Whereas, the T_c of the bi-filler nanocomposites with half filler content were 1.4 °C–3.7 °C higher than those of the CB-loaded and 0.8 °C–1.5 °C lower than those of the CNT-loaded nanocomposites. According to the isothermal crystallization test, applying shear and increasing the shear rate and time accelerated the crystallization of the mono-filler and bi-filler nanocomposites, however to different extents. Under shear, the crystallization rate of mono-filler and bi-filler nanocomposites increased by 2 and 5 times, respectively. Electrical conductivity measurement revealed that shearing reduced the conductivity of the mono-filler and bi-filler nanocomposites by 120 and 200 times, respectively.

Researchers are actively exploring sustainable alternatives to conventional materials through the development of biopolymer nanocomposites (NCs). In this study, blend NCs of polyvinyl alcohol (PVA) and Maranta arundinacea starch, reinforced with lithium silver oxide (LiAgO) nanoparticles (NPs), were synthesised using water as a green solvent. The successful incorporation of LiAgO into the polymer matrix was confirmed by Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD), which revealed characteristic peaks of the nanoparticles. UV-visible spectroscopy showed enhanced optical absorbance with increasing LiAgO concentration, with the 9 wt% nanocomposite showing optimal performance, including the lowest bandgap and highest refractive index. Scanning electron microscopy (SEM) revealed uniform nanoparticle dispersion at 9 wt%, whereas higher concentrations led to agglomeration. Thermal analysis showed improved thermal stability in NCs with the inclusion of LiAgO compared to a pure polymer blend. Impedance analysis showed that NCs exhibited improved electrical conductivity and dielectric properties, with 9 wt% nanocomposite achieving the highest AC conductivity of 1.4 × 10⁻⁶ S/cm at 110°C. Mechanical testing further confirmed that the 9 wt% nanocomposite demonstrated significant improvements in tensile strength, Young’s modulus and surface hardness, accompanied by reduced elongation at break. Antibacterial assay against Escherichia coli showed increasing antimicrobial efficacy with higher NP content, with the 12 wt% NC displaying the largest inhibition zone. These findings underscore the potential of PVA/ Maranta arundinacea starch /LiAgO NCs as biodegradable, multifunctional materials for optoelectronic and antibacterial applications.

This paper presents a semi-analytical approach to investigate the nonlinear static and dynamic buckling responses of functionally graded porous graphene-reinforced spherical shells and circular plates with spider-web stiffeners and piezoelectric layer under mechanical and thermal loads. Graphene and porosity are designed to be continuously varied in the thickness direction of plates and shells. By applying the energy method, the equilibrium and motion equations for spider-web stiffened plates and shells are derived by using the improved smeared stiffener technique and the nonlinear Donnell shell theory, taking into account the geometrical imperfection. The resulting equations are solved to obtain explicit expressions for static buckling and postbuckling responses, and numerical results for dynamic responses. Static and dynamic buckling analysis of the considered structures shows the effects of the graphene, porosity, stiffeners, and other input parameters on the static and dynamic buckling behavior of plates and shells.

A numerical and experimental investigation is carried out in this study to evaluate the crashworthiness behavior, the energy-absorbing parameters, and the failure mode of thermoplastic composite energy absorbers under axial loading. The energy absorbers are thin-walled circular tubes made of woven polyphenylene sulfide carbon composite and have a bevel trigger on the top. Finite element analysis are conducted to predict the structural behavior of the tubes. To validate the numerical model, four specimens are manufactured and tested under an axial compression load. During the tests, the load and displacement are measured by a load cell, the evolution of the longitudinal strains is captured by digital image correlation, and the progression of the failure is recorded by a high speed camera. The tubes show a progressive failure mode, with delamination between the middle plies. A stable damage propagation is observed throughout the tests, where the bevel trigger plays an important role in increasing the stability and failure progression of the thin-walled tubes. The test results are compared to the numerical prediction, with good agreement for both crashworthiness parameters and delamination behavior. The thermoplastic composite energy absorbers achieved specific energy absorption values of up to 70 kJ/kg, indicating an adequate crashworthiness performance.

Utilization of biodegradable thermoplastic polylactic acid (PLA) has restricted its widespread application because of the cost and brittle nature of materials. Therefore, this study focused on providing solutions to the brittle nature of PLA using a cost-effective and highly efficient filler material that could be accessed in abundance from agricultural industry. Firstly, different monomers were produced based on ultrafine fully vulcanized powdered natural rubber grafted methyl methacrylate monomer (UFPNR-g-PMMA) at various proportions and examined considering crosslink efficiency and morphology to determine the optimum proportion. Secondly, the optimized UFPNR-g-PMMA powder was used as a toughening filler in the PLA matrix to produce the composite. Furthermore, flexural and impact strength tests were used to examine the toughening effects of the UFPNR-g-PMMA filler. The results recorded suggests that the aim of the study has been achieved considering that 3-4 and 2-3-folds improvements achieved with flexural strain and impact strength with the UFPNR-g-PMMA filler at 5-20 wt/wt%, respectively. Thermal stability of the PLA/ UFPNR-g-PMMA composites has also improved drastically. The toughening performance exhibited by the UFPNR filler in the PLA matrix suggests its potential as an alternative material for 3D printing and packaging.

In the pursuit of advanced materials with enhanced thermo-mechanical properties, unidirectional short glass fiber (USGF)-reinforced polyethylene composites incorporating alumina nanoparticles can represent a potentially promising development. This study shows the constructive interplay between the multiscale agents, nanofiller/polymer interphase and the overall composite performance, employing the concept of representative volume element (RVE) and the finite element analysis. First, an RVE is created with spherical alumina nanoparticles dispersed randomly within the polyethylene matrix. Next, a different RVE is formed where USGFs are incorporated into the nanoparticle-filled polymer, which serves as the base material. By analyzing the RVEs via the finite element method (FEM), the elastic moduli and coefficients of thermal expansion (CTEs) of the ternary composites are predicted. The validity of the numerical model is assessed by comparison with previous literature, providing an acceptable agreement. The effects of volume fraction and geometry of alumina nanoscale particles and glass microscale fibers on the thermo-elastic constants are investigated. The findings indicate that dispersing alumina nanoparticles into the polyethylene can improve the thermo-elastic properties of the ternary composites. The elastic modulus and CTE in the transverse direction is significantly improved by reducing the diameter of alumina nanoparticles. It is found that nanofiller/polymer interphase region affects mostly the transverse thermo-elastic properties.

Combining different types of materials increases its importance in lightweight component studies. However, conventional joining methods cannot provide perfect joining of dissimilar materials. In this context, glass fiber-reinforced Elium based thermoplastic materials and an AISI 304 stainless steel have been joined using laser-hybrid joining. After the joining operation, mechanical characterization tests (lap shear, compression shear, and three-point bending) were performed on coupon samples. In addition, after the tests, the joint grids have been examined and the failure type (cohesive/adhesive/mixed) has been analyzed. Moreover, fatigue tests have been applied to highlight the endurance of tensile-tensile loading condition. Finally, as a result of all these tests, it was determined that the laser-assisted bonding has a lap shear strength of nearly to 18 MPa and a fatigue life of up to 10⁶ cycle at 30% UTS. As a result of all these tests, it was determined that the material maintains its strength in both dynamic tensile-tensile loading and static mechanical tests with the laser hybrid joining.

The non-isothermal crystallization kinetics of both pure ethylene-vinyl acetate copolymer (EVA) and EVA/butadiene rubber (BR) thermoplastic vulcanizate (TPV) which was prepared through dynamic vulcanization were investigated via differential scanning calorimetry (DSC). The mechanism of non-isothermal crystallization was analyzed using the Avrami model modified by the Jeziorny method, along with the Ozawa and Mo methods. The results demonstrated that the non-isothermal crystallization behavior of both EVA/BR TPV and pure EVA could not be accurately described by the Ozawa method. In contrast, the Jeziorny and Mo methods provided a more precise representation of the crystallization behavior. Data analysis revealed that EVA exhibited a faster crystallization rate compared to EVA/BR TPV. In contrast, the initial crystallization temperature of EVA was lower than that of the EVA/BR TPV. In conclusion, BR served as a nucleating agent in EVA/BR TPV, facilitating the nucleation of the EVA phase. However, due to the steric hindrance effects, the EVA crystal growth process was hindered by the existence of BR phase.

This study investigates the effects of gamma irradiation on the structural, optical, and electronic properties of PVC/CoSe/TiO₂ nanocomposite films, with irradiation doses ranging from 0 to 100 kGy. X-ray diffraction (XRD) analysis reveals the predominantly amorphous nature of the PVC matrix, showing a broad halo centered around 2θ ≈ 15–25°. While no new crystalline phases were observed and major peak positions remained unchanged upon irradiation, subtle variations in the broad amorphous halo’s intensity suggest potential localized rearrangements within the PVC matrix, particularly a slight decrease in overall intensity with increasing dose. Energy-dispersive X-ray spectroscopy (EDX) verifies the presence of all constituent elements (C, Cl from PVC; Co, Se from CoSe; Ti, O from TiO₂), confirming the successful incorporation and distribution of CoSe and TiO₂ nanoparticles within the PVC matrix. Ultraviolet-visible (UV-Vis) spectroscopy demonstrates a clear influence of gamma irradiation on the nanocomposite’s optical properties, evidenced by a redshift in the absorption edge of up to X nm (from 450 nm to 480 nm) and an increase in visible light absorption by up to Y% (15–20%) with increasing dose. These changes are attributed to a combination of radiation-induced defect formation and potential subtle structural modifications. Analysis of the volume and surface energy loss functions (VELF and SELF) further supports alterations in the electronic structure and surface properties due to irradiation. The observed tunability of optical properties and enhanced light absorption hold promise for applications in photocatalysis, solar energy conversion, and optoelectronic devices. However, the study emphasizes that these optical changes may not solely arise from gross structural changes or simple defect formation. The potential contribution of subtle changes in local atomic order, free volume, or interfacial effects, undetectable by XRD, is highlighted. Therefore, future work employing complementary techniques such as electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) is proposed to gain a more comprehensive understanding of the complex structure-property relationships in these irradiated nanocomposites and to precisely correlate the observed optical changes with specific defect types and their evolution under gamma irradiation.