Polyetherimide Research Articles

Preparation of a Solvent-Resistant Nanofiltration Membrane of Liquefied Walnut Shell Modified by Ethylenediamine.

N,N-dimethylformamide (DMF) has excellent chemical stability and is widely used as an aprotic polar solvent. In order to reduce production costs and reduce pollution to the surrounding environment, it is necessary to recycle and reuse DMF. Previous research has found that the thin film composite nanofiltration membrane prepared from liquefied walnut shells exhibited a high rejection rate in DMF, but relatively low permeance and mechanical strength. In order to increase permeance without compromising the separation performance, ethylenediamine (EDA) is used as a modifier to graft onto the structure of liquefied walnut shell through the Mannich reaction. Then, modified liquefied walnut shell as an aqueous monomer reacts with trimesoyl chloride (TMC) via the interfacial polymerization method on the EDA-crosslinked polyetherimide (PEI) membrane. The results show that the permeance of the prepared membrane is significantly improved by an order of magnitude, demonstrating a rejection rate of 98% for crystal violet (CV), and a permeance of 3.53 L m-2 h-1 bar-1 in DMF. In conclusion, this study reveals the potential of utilizing liquefied walnut shells as raw materials for preparing high-performance separation membranes and demonstrates that surface modification is a feasible approach to enhance permeance of membranes without sacrificing the rejection rate.

Tailoring the CO2 permeation of Pebax1657/polyether imide thin film composite membrane via embedding Ag-based metal-organic framework

Thin-film composite/nanocomposite (TFC/TFN) membranes count as the latest version of carbon capture membranes characterized by their excellent gas permeance, great selectivity, cost-effectiveness, and the ability to separately manage and tune the constituents of the individual layer. In this regard, Pebax®1657 embedded with synthesized Ag-BTC metal-organic frameworks (MOFs) was coated on the polyether imide (PEI) support layer to produce TFNs. To assess the impacts of Ag-BTC particles (carboxyl-rich surface particles) on the features of the constructed TFC/TFN membranes and their gas permeation qualities, several CO2/N2 and CO2/CH4 separation experiments (mixed and pure gas testing) were carried out. Ag-BTC particles were distributed appropriately within the Pebax1657 matrix, improving the gas permeability (particularly for CO2) and enhancing CO2/N2 and CO2/CH4 separation factors. A simultaneous increase in CO2 permeability and gas pair selectivities was observed with rising feed pressure. A 394.97 Barrer CO2 permeability and 38.20 CO2/N2 and 21.25 CO2/CH4 selectivities were obtained for the TFN filled with 3 wt% Ag-BTC at 10 bar and 30 °C. A mixed gas test also showed a similar trend but lower values than a pure one. The results for the humidified conditions exhibited higher CO2 permselectivities in comparison with the dry gas given the water molecules facilitate the CO2 transportation through the Pebax®1657 matrix. Finally, enhancing Ag-BTC filler content and increasing the input pressure provided excellent conditions for approaching Robeson’s limit.

Electromagnetic interference shielding behavior of polypyrrole-impregnated poly(ether imide)/sulfonated poly(ether ether ketone) composites

Electromagnetic interference (EMI) shielding materials are of major interest for modern society due to proliferation of electronic instruments and it reports the designing of electromagnetic radiations shielding material against electromagnetic pollution. Here, we prepared a series of composites comprising polyetherimide (PEI) with sulfonated poly(ether ether ketone) (SPEEK) by solvent casting method, having SPEEK loading ranging from 10 to 50 wt%. All the composites and PEI films were impregnated with pyrrole via in situ polymerization method to enhance their electrical conductivity. The morphology of composites was studied by SEM (scanning electron microscopy) and XRD (X-ray diffraction) analysis. Structural and thermal properties were investigated by Fourier-transform infrared spectroscopy (FT-IR), TGA and DSC, respectively. Electrical conductivity was analyzed by two probe method. Maximum conductivity of 2.24*10−4 S/cm was achieved at 50 wt% loading of SPEEK, due to the presence of conductive network between polypyrrole (PPy) and SPEEK throughout PEI matrix. These composites exhibited an average electromagnetic interference SET values up to −21 dB which makes them capable for shielding in the frequency range of 8.2–12.0 GHz (X-band). This study provides an avenue for fabrication of absorption dominating EMI shielding composites, which is promising material for commercial applications in next generation electronic instruments.

Material-Dependent Effect of Common Printing Parameters on Residual Stress and Warpage Deformation in 3D Printing: A Comprehensive Finite Element Analysis Study

Additive manufacturing (AM), commonly known as 3D printing, has gained significant popularity for its ability to produce intricate parts with high precision. However, the presence of residual stresses and warpage deformation are common issues affecting the quality and functionality of 3D-printed parts. This study conducts a comprehensive finite element analysis (FEA) to investigate the material-dependent impact of key printing parameters on residual stress and warpage deformation in 3D printing. The research focuses on three distinct materials: polyetherimide (PEI), acrylonitrile butadiene styrene (ABS), and polyamide 6 (PA6). Various printing parameters are systematically varied, including printing temperature, printing speed, bed temperature, infill density, layer thickness, and infill pattern. The study employs the Taguchi L27 orthogonal array and employs the analysis of variance (ANOVA) statistical technique to assess the significance of the input parameters. The obtained results reveal that certain parameters exhibit a greater sensitivity to material differences, whereas the layer thickness parameter demonstrates a relatively lower sensitivity. Notably, infill density and printing temperature play a crucial role in reducing residual stress for PA6, while the infill pattern parameter proves to be a significant contributor to minimizing warpage deformation across all three materials. These findings underscore the importance of conducting material-specific analyses to optimize 3D printing parameters and achieve the desired quality outcomes while mitigating residual stress and warpage deformation.

Zr‐Based Metal‐Organic Framework UiO‐66/Ultem® 1000 Membranes for Effective CO2/H2 Separation

AbstractMixed‐matrix membranes (MMMs) using UiO‐66 nanofillers as dispersing inorganic phase and polyetherimide (PEI) as continuous polymeric matrix were synthesized. Different UiO‐66 loadings of 10, 20, and 30 wt % were applied. The morphology and UiO‐66 dispersion over the prepared MMMs were examined. Gas separation measurements were performed for H2/CO2 gas mixture to evaluate the influence of UiO‐66 on the separation yield of resulting membranes. When compared with pristine PEI membranes, MMMs containing metal‐organic framework (MOF) nanoparticles revealed superior H2 permeability and H2/CO2 separation factor, e.g., maximum permeability values of 14.6 and 5.5 Barrer were observed for H2 and CO2 at a filler loading of 10 wt % and an applied pressure of 4.0 bar.

Research of the Pre-Processing Strategy Influence on the Tribological Properties of PEI Processed by Fused Filament Fabrication Technology

The aim of this study was to investigate the effect of Fused Filament Fabrication (FFF) layer generation strategies on abrasive wear resistance and compare the material loss of PEI (polyetherimide) plastic specimens based on different specimen building strategies. The study also compares a newly proposed path generation strategy (parallel paths in layers with 0.25 mm displacement of alternate layers) with samples from a previous study where samples were printed without displacement of alternate layers, i.e., layers stacked perpendicularly to each other. The primary focus was on the weight loss due to abrasive wear before and after the test. The tests were conducted on a tribometer constructed according to ASTM G65/16 standards using dry sand. Two printing directions were examined: X (longitudinal) and Z (portrait) orientations. For X construction, three orientations of deposition path generation were utilized, resulting in three samples for each orientation (nine samples in total for X construction). The same approach was applied to Z construction, resulting in another nine samples. In total, 18 samples were produced and tested. The deposited infill path width was 0.5 mm, and the layer thickness used in printing was 0.254 mm. Garnet abrasive Fe3Al2(SiO4)3 was employed in this test. Analysis of the experimental data revealed a relationship between the construction method (X and Z orientations) and the variation in different orientations (1X–3X and 1Z–3Z). The research results can be categorized as overall and partial. The overall results indicate poorer wear resistance for 1X–3X and 1Z–3Z specimens, while the partial results illustrate the findings within each individual specimen.

Carboxylated Poly (p-Phenylene Terephthalamide) Reinforced Polyetherimide for High-Temperature Dielectric Energy Storage.

Dielectric energy storage polymers play a vital role in advanced electronics and electrical systems, due to their high breakdown strength, excellent reliability, and easy fabrication. However, the low dielectric constant and poor thermal resistance of dielectric polymers limit their energy storage density and working temperatures, making them less versatile for broader applications. In this work, a novel carboxylated poly (p-phenylene terephthalamide) (c-PPTA) is synthesized and employed to simultaneously enhance the dielectric constant and thermal resistance of polyetherimide (PEI), leading to a discharged energy density of 6.4 J cm-3 at 150 °C. The introduction of c-PPTA molecules effectively reduces the ΠΠ stacking effect and increases the average chain spacing between polymer molecules, which is conducive to improving the dielectric constant. Additionally, c-PPTA molecules with stronger positive charges and high dipole moments can capture electrons, resulting in reduced conduction loss and enhanced breakdown strength at high temperatures. The coiled capacitor fabricated with the PEI/c-PPTA film exhibits superior capacitance performances and higher working temperatures compared to commercial metalized PP capacitors, demonstrating great potential for dielectric polymers in high-temperature electronic and electrical energy storage systems.

Efficient red-emitting carbon dots for bioimaging and spectral engineering by polyetherimide modification

A novel type of red-emitting carbon dots was synthesized using urea and neutral red via the solvothermal method at a temperature of 200 °C for 4 h. The resulting CDs, named NR-CDs, display a distinct red emission at 620 nm when excited at a wavelength of 470 nm, achieving a quantum yield of 61.11% in acetone. Interestingly, NR-CDs exhibit strict solvent polarity dependence, i.e. the emission wavelength of NR-CDs red-shifts with an increase in solvent polarity. Besides, when incubated with NR-CDs and excited by an excitation wavelength of 470 nm, 4-T1 cells emit a clear red fluorescence. Meanwhile, high-quality in-vivo fluorescent images of zebrafish embryos and larvae were obtained by incubating with NR-CDs. Moreover, by modifying with polyetherimide (PEI), the peak value of PEI-NR-CDs shifts from 620 nm to 596 nm, and the emission is increased by 264 %. Co-localization experiment with commercial dye (Lyso-Tracker Green) shows that PEI-NR-CDs are localized in lysosomes and could be used as a lysosomal tracer for cells. Furthermore, PEI-NR-CDs were prepared into fluorescent ink, which exhibited orange fluorescence under UV light. All results demonstrate that as-obtained NR-CDs and PEI-NR-CDs can be used as reagent for fluorescent-imaging application.

A new protocol for radio frequency heating of low-moisture, viscous sauces and its temperature uniformity optimisation

AbstractRadio frequency (RF) heating of agri-food, especially low moisture viscous sauces (LMVS), have obvious advantages. However, uneven heating is one main problem of RF heating technology that has to be solved. Due to the unclear heating mechanism and the difficulty to measure the three-dimensional temperature distribution in the heated object, computer-aided analysis method was adopted. Based on the RF heating numerical calculation model after experimental verification and the characteristics of polyetherimide (PEI) assisted RF heating of peanut butter (PB), this study proposed an improved method for an existing protocol. Meanwhile, parameters of the new protocol were optimised by the Multi-objective Global Optimisation (MGO) of its surrogate model. Results demonstrated that the best size of PEI block in the new protocol was Φ100 × 9.5 mm and the positional height was 12 mm. When the pasteurisation temperature Tp was set to 70 °C and the control temperature Tc was set to 75 °C, the temperature uniformity evaluation indices, Over-shoot Temperature Control Index (OTCI) and Targeted Penetration Depth (TPD), were 0.920% and 3.975 mm, respectively. Compared with 4.845% and 4.940 mm before improvement, the new protocol achieved significant optimisation and improved the temperature uniformity effectively. This also proved the feasibility of MGO method of surrogate model in relevant studies.

Synthetically tunable polymers, free volume element size distributions, and dielectric breakdown field strengths

Four polyetherimide (PEI) polymers were synthesized with different end groups, while leaving the molecular weights, glass transition temperature, thermal properties, and dielectric constant essentially unchanged. The Restricted Orientation Anisotropy Method (ROAM), an ultrafast infrared laser technique, was used to measure the films’ free volume elements (FVEs) radius probability distribution (RPD) curves. This technique exploits the observation that a vibrational probe’s molecular reorientation dynamics inside a polymer film’s FVEs are sterically restricted by the surfaces of the FVEs. The measured RPD curves displayed significant changes in shape and center positions for the PEI polymers with different end cap. The results demonstrate that structural changes to the end groups of a polymer can significantly modify its microscopic morphology, which is consistent with other experiments that observed changes in macroscopic observables. The thin film samples’ breakdown fields (EBD) were measured, and a correlation between polymer films having a higher probability of large FVEs and lower EBDs was observed. This work demonstrates that the nanoscopic chain packing structure that controls the nature of the FVEs and breakdown field properties of PEI are synthetically tunable, without the need to change the main chain chemical structure. The results provide some experimental evidence for the theoretical model of electron-acceleration inside FVEs as the microscopic origin of polymer film dielectric breakdown. The results also provide a framework for the study of other polymer dielectrics, and suggest that design of high breakdown field polymer films may involve minimizing FVE sizes, particularly the large FVE tails of the size distribution.

Synergy of carbon fiber fabric-based heating element and h-BN modified insulated film on resistance welding of thermoplastic composites

A sandwich-structure heating element (HE) of hexagonal boron nitride (h-BN) decorated polyetherimide (PEI) and plain weave carbon fiber fabric (CFF) of different fabric weight was fabricated to bond carbon fiber reinforced polyetherimide (CF/PEI) laminates by resistance welding. The effects of fabric weight of CFF and thermal conductivity of insulating films on the lap shear strength (LSS) of resistance welding joints and failure mode of CF/PEI composites were investigated. The LSS of the composite joints increased by 31.4% due to the improvement the thermal conductivity of PEI composite film, as well as the reduction of the current leakage during welding process. Intralaminar failure of joints and breakage of carbon fibers of CFF in HE was observed.

Ultrathin organic solvent nanofiltration membrane with polydopamine-HKUST-1 interlayer for organic solvent separation

Polydopamine (PDA) and metal-organic skeleton HKUST-1 were co-deposited on the base membrane of hexamethylenediamine (HDA)-crosslinked polyetherimide (PEI) ultrafiltration membrane as the interlayer, and high-throughput organic solvent nanofiltration membrane (OSN) was prepared by interfacial polymerization and solvent activation reaction. The polyamide (PA) layer surface roughness from 28.4 nm in PA/PEI to 78.3 nm in PA/PDA-HKUST-10.6/PEI membrane, reduced the thickness of the separation layer from 79 to 14 nm, and significantly improved the hydrophilic, thermal and mechanical properties. The flux of the PA/PDA-HKUST-10.6/PEI membrane in a 0.1 g/L Congo Red (CR) ethanol solution at 0.6 MPa test pressure reached 21.8 L/(m2·hr) and the rejection of CR was 92.8%. Solvent adsorption test, N, N-dimethylformamide (DMF) immersion experiment, and long-term operation test in ethanol showed that the membranes had high solvent tolerance. The solvent flux test demonstrated that, under the test pressure of 0.6 MPa, the flux of different solvents ranked as follows: methanol (56.9 L/(m2·hr)) > DMF (39.6 L/(m2·hr)) > ethanol (31.2 L/(m2·hr)) > IPA (4.5 L/(m2·hr)) > N-hexane (1.9 L/(m2·hr)). The ability of the membranes to retain dyes in IPA/water dyes solution was also evaluated. The flux of the membrane was 30.4 L/(m2·hr) and the rejection of CR was 91.6% when the IPA concentration reached 50%. This OSN membrane-making strategy is economical, environment-friendly and efficient, and has a great application prospect in organic solvent separation systems.

Laser-synthesis of conductive carbon-based materials from two flexible commercial substrates: A comparison

One of the key challenges in the field of flexible electronics relies on finding conductive materials that can withstand bending and stretching stresses while maintaining their performance. In this context, this work presents a comparative study of laser-induced conductive materials from the direct laser-scribing of two commercial flexible films: the benchmark Kapton® HN polyimide (PI) precursor and the UltemTM 1000 polyetherimide (PEI) alternative contender. The synthesis process on both materials is optimized in terms of electrical conductivity using a high-performance galvanometric laser with a wavelength of 532 nm for the fabrication of multiple samples at different laser powers and speeds. The samples are structurally characterized using Scanning Electron Microscopy (SEM), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Fourier-Transform Infrared Spectroscopy (FTIR) aiming at understanding the chemical and physical changes of the ablated material. The results demonstrate that the proposed setup is feasible for the synthesis of uniform and reliable conductive patterns on the surface of both substrates with high reproducibility. In particular, it is proved that PEI is more suitable precursor for flexible electronics applications which demand high electrical conductivity, leading to a sheet resistance of 3.62 ± 0.35 Ω/sq at 0.8 W and 5 mm/s once the laser-synthesis process is optimized (against the 6.04 ± 0.63 Ω/sq at 0.6 W and 5 mm/s offered by the LIG on PI). The performance of both laser-induced patterns as electrodes for the fabrication of electrochemical capacitors is also studied and compared in terms of areal specific capacitance.

Low-pressure air plasma-assisted acrylic grafted polyetherimide ultrafiltration membranes with excellent oil-water separation and high anti-fouling performances

This paper reports the first surface modification of polyetherimide (PEI) ultrafiltration membranes using low-pressure air plasma-treated surfaces to induce acrylic acid (AA) graft polymerization, significantly improving their retention and fouling resistance properties. The successful formation of graft layers was verified by water contact angle (WCA) measurement of hydrophilic changes and Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis of the surface chemistry. Scanning electron microscopy (SEM) was used to analyze the morphological features, and atomic force microscopy (AFM) was tested for changes in surface roughness. The overall property changes after grafting were evaluated by mechanical tests and filtration tests. Methyl tert-butyl ether (MTBE) was chosen to measure the oil-water separability. The results showed that the membrane surface obtained PAA dense graft layer and improved hydrophilicity (CA from 57.62° to 29.26°) with no loss of tensile properties. In addition, the modified grafted membranes showed a high retention rate of BSA of 95.1 %, while the rejection rate of MTBE increased from 31.8 % to 75.9 %. Notably, PEI-g-AA fully recovered the permeability by simple water backwashing, exhibiting excellent antifouling performance. Therefore, this communication demonstrates that graft modification on the surface of PEI membranes is feasible and effective, and provides a new idea of PEI modification, which is valuable for exploring the development of high-efficiency ultrafiltration membranes.

Interfacial origin of dielectric constant enhancement in high-temperature polymer dilute nanocomposites

The origin of dielectric constant enhancement in high-temperature (high glass transition temperature Tg) polymer dilute nanocomposites is investigated via Infrared (IR) Spectroscopy applied through Atomic Force Microscope (AFM) and density functional theory (DFT) calculations. The dielectric constant can be greatly enhanced by trace nanofiller loadings (<0.5 vol. %) in a broad class of high-temperature polymers without affecting or even with a positive influence on breakdown strength and dielectric loss. This avenue provides attractive polymer systems for high-performance polymer-based capacitive energy storage in a wide temperature range. In the dilute nanocomposites, the interface regions between the polymers and trace nanofillers are the key to the observed dielectric constant enhancement. This Letter employs AFM-IR to study chain packing in the interface regions of polyetherimide (PEI) dilute nanocomposites. The experimental results and DFT calculations indicate that flexible linkages, i.e., ether groups in PEI, play a crucial role in inducing heterogeneous morphologies in the interface regions. These results are confirmed by studies of PI(PDMA/ODA) and other dilute polymer nanocomposites in the literature as well as by lack of dielectric constant enhancement in PI(Matrimid® 5218) that does not contain flexible linkages.

Synergy of charge capture and transfer by Ni-MOF nanosheets for enhancing energy storage performance of polyetherimide-based dielectric nanocomposites

Polymer-based dielectric nanocomposites with excellent energy storage performance and good thermal stability are essential to meet the demand for dielectric capacitors operating under high-temperature environments. However, there is still a challenge to high-temperature breakdown strength and energy density due to the increase in leakage current with temperature and applied electric field. In this work, Ni-based metal-organic framework nanosheets (Ni-MOFs) are synthesized by a sonication-assisted solution method and introduced into polyetherimide (PEI) to fabricate Ni-MOFs/PEI dielectric nanocomposites. As a result, the nanocomposites containing 2 wt. % Ni-MOFs exhibit a significantly enhanced breakdown strength of 640 kV/mm and a discharged energy density of 6.37 J/cm3 at 150 °C, which are 48% and 228% higher than those of pure PEI, respectively. This enhancement could be attributed to the synergistic effect of charge capture and transfer induced by wider bandgap and π–d conjugation of Ni-MOFs, which not only act as deep traps to capture charges at the interface but also transfer the charges along the in-plane direction to uniform the local electric field, thus reducing the leakage current and conduction loss. This work provides an effective strategy for the design of high-performance dielectric nanocomposites based on polymer.

Enhancing the high-temperature energy storage performance of PEI dielectric film through deposition of high-dielectric PZT coating layer

Dielectric film capacitors are a highly ubiquitous and indispensable electronic component, serving a crucial role in a wide array of electronic devices and power systems. Despite their extensive use, polymer film capacitors are often hampered by the conduction loss that ensues when they are subjected to high electric fields and temperatures. As a result, this leads to a significant reduction in energy density and charge-discharge efficiency. To solve this issue, magnetron sputtering technology was used to create a sandwich structure made of polyetherimide (PEI) thin films with lead zirconate titanate (PZT) inorganic layers coated on both sides. This remarkable innovation has successfully introduced the high dielectric PZT layer in the PEI film/metal electrode, substantially augmenting the barrier height at the dielectric/polymer interface. This has also resulted in a marked decrease in conduction loss, as conclusively validated by the experimental findings. At 150 °C and with charge-discharge efficiency above 90%, the maximum discharged energy density is 3.26 J/cm3, which is increased by 263% compared to the pristine PEI films (1.24 J/cm3 at 290 MV/m and 150 °C). This study designed a unique inorganic barrier layer of PZT to increase the energy storage capability of polymer dielectric films in high-temperature environments.

Enhanced Interfacial and Dielectric Performance for Polyetherimide Nanocomposites through Tailoring Shell Polarities

Polyimide (PI) and its derivative polyetherimide (PEI) have been widely investigated as promising candidates for dielectric energy storage due to their excellent intrinsic features. However, most of the current research for PI- or PEI-based dielectric nanocomposites only focuses on a certain polar group contained in a dianhydride monomer, while there are very few studies on exploring the effect of a series of polar groups derived from various dianhydride monomers on the dielectric properties of nanocomposites. To fill this gap, we herein fabricated and investigated a series of novel hyperbranched polyimides grafted on barium titanate nanoparticles (HBPI@BT) using different dianhydride monomers and their nanocomposites with the PEI matrix. The results showed that sophisticated hyperbranched structures effectively alleviated the incompatibility between fillers and the matrix, thus significantly improving the bonding energy of nanocomposites, especially for HBPI-S@BT/PEI (797.7 kJ/mol). The Ud of HBPI-S@BT/PEI reached 8.38 J/cm3, which is 3.3 times higher than that of pure PEI. The HBPI-F@BT/PEI nanocomposites achieved high breakdown strength (∼500 MV/m) and low dielectric loss (0.008) simultaneously. The dielectric constants of HBPI@BT/PEI nanocomposites remained at a stable level from 25 to 150 °C. This work provides us promising hyperbranched structured materials for potentially advanced dielectric applications such as field effect transistors.

Enhanced Energy Density of Polyetherimide Using Low Content Barium Titanate Nanofillers

Dielectric polymer composites containing low content inorganic fillers exhibit superior dielectric properties and endurance for simultaneous enhancement of dielectric constant and breakdown strength. Polyetherimide (PEI) composites incorporated with nanosized BaTiO3 of 0.1vol.% loading fraction was developed in this work and their breakdown strength reached a maximum value along with the highest dielectric constant. The discharged energy density increased to 8.33 J/cm3, which is 2.33 times that of pure PEI. The composite film also maintained an excellent endurance after 104 cycles of fatigue test. The low-level filling for enhanced composite property may reduce the challenge in film scale-up manufacturing.

Analysis of self-tapping screw joints in fibre glass reinforced PEI polymer used in the automotive industry

This article presents a study of the joining of polyetherimide (PEI) polymer parts reinforced with fibre glass which has great application in the automotive sector. A simulation model based on the finite element method is proposed. For the modelling of the polymeric material, the three-network viscoplastic (TNV) rheological model was used, with very adequate results and producing a good fit with the experimental data. In addition, a methodology is proposed that allows simplifying a three-dimensional to an axisymmetric model, which implies a notable reduction in computational cost. In addition, the work includes an experimental analysis that evaluates the tightening torque under conditions of assembly repetitiveness, relaxation over time and influence of thermal cycles. These scenarios have a different influence depending on the geometry of the self-tapping screw used. Regarding repetitiveness, it has been verified that PF-30 (CELOspArk®) loses 17.16% while in Δ-PT (DELTA PT®) it loses up to 41.93% in the tenth repetition. In contrast, in the relaxation over time scenario, the PF-30 loses 13.38% and the Δ-PT loses 17.82%. Finally, regarding the thermal cycles, cooling allows to slightly delay the loss of tightening torque in both screws in a similar way; however, in the heating stage, 36.89% is lost with PF-30 and only 14.66% with Δ-PT. This study represents an improvement in the knowledge of the joining processes of self-tapping screws with polymeric materials of an engineering nature. The simulation model can be easily adapted to other materials and other geometries, and the experimental study offers a vision of the evolution of tightening conditions in realistic operating scenarios.