Search Results (56)

The insulation layer of flame-retardant cables plays a critical role in mitigating fire hazards by influencing toxic gas emissions and the accuracy of fire modeling. This study systematically explores the pyrolysis kinetics and volatile gas evolution of flame-retardant polyvinyl chloride (PVC) and polyethylene (PE) insulation materials using advanced TG-FTIR-GC/MS techniques. Distinct pyrolysis stages were identified through thermogravimetric analysis (TGA) at heating rates of 10–40 K/min, while the KAS model-free method and Málek fitting function quantified activation energies and reaction mechanisms. Results revealed that flame-retardant PVC undergoes two major stages: (1) dehydrochlorination, characterized by the rapid release of HCl and low activation energy, and (2) main-chain scission, producing aromatic compounds that contribute to fire toxicity. In contrast, flame-retardant PE demonstrates a more stable pyrolysis process dominated by random chain scission and the formation of a dense char layer, significantly enhancing its flame-retardant performance. FTIR and GC/MS analyses further highlighted distinct gas evolution behaviors: PVC primarily generates HCl and aromatic hydrocarbons, whereas PE releases olefins and alkanes with significantly lower toxicity. Additionally, the application of a classification and regression tree (CART) model accurately predicted mass loss behavior under various heating rates, achieving exceptional fitting accuracy (R² > 0.98). This study provides critical insights into the pyrolysis mechanisms of flame-retardant cable insulation and offers a robust data framework for optimizing fire modeling and improving material design. Full article

The dielectric relaxation behavior of polymeric materials is critical to their performance in electronic, insulating, and energy storage applications. This study presents an electrical fractional model (EFM) based on fractional calculus and the complex electric modulus ($M^{*}\mathit{=}{M}^{\prime }\mathit{+}i{M}^{″}$) formalism to simultaneously describe two key relaxation phenomena: $\alpha$-relaxation and interfacial polarization (Maxwell–Wagner–Sillars effect). The model incorporates fractional elements (cap-resistors) into a modified Debye equivalent circuit to capture polymer dynamics and energy dissipation. Fractional differential equations are derived, with fractional orders taking values between 0 and 1; the frequency and temperature responses are analyzed using Fourier transform. Two temperature-dependent behaviors are considered: the Matsuoka model, applied to $\alpha$-relaxation near the glass transition, and an Arrhenius-type equation, used to describe interfacial polarization associated with thermally activated charge transport. The proposed model is validated using literature data for amorphous polymers, polyetherimide (PEI), polyvinyl chloride (PVC), and polyvinyl butyral (PVB), successfully fitting dielectric spectra and extracting meaningful physical parameters. The results demonstrate that the EFM is a robust and versatile tool for modeling complex dielectric relaxation in polymeric systems, offering improved interpretability over classical integer-order models. This approach enhances understanding of coupled relaxation mechanisms and may support the design of advanced polymer-based materials with tailored dielectric properties. Full article

This study examines the UVB-induced (Ultraviolet B radiation) degradation of carbon black-filled polyvinyl chloride (CB-PVC) composites. After 500 h of exposure, the material exhibited a 30.13% drop in dielectric strength, a 27.6% increase in surface roughness, and significant pit formation, indicating substantial physicochemical deterioration. Degradation followed a triphasic kinetic pattern: an initial induction phase, an autocatalytic acceleration, and a stabilization phase, driven by radical propagation and photo-oxidation. These findings highlight the complex role of UVB in the photodegradation of cable sheeting. Full article

Penetration points on walls must include firestop measures to prevent the spread of fire. Countries worldwide have established standardized testing protocols for firestop methods, and firestop products must pass relevant tests before they can be used in buildings. In the present study, a simple method was developed to enhance the smoke leakage performance and fire resistance of existing polyvinyl chloride (PVC) pipes passing through walls. Two sets of smoke leakage tests were performed, followed by two sets of fire tests. The smoke leakage tests were nondestructive and thus did not damage the specimens; consequently, the same specimens could be used in the smoke leakage and fire tests. The results of the smoke leakage tests indicate that the method using PVC pipes wrapped with galvanized steel sleeves outperforms the method without such wrapping. Moreover, the results of the fire tests suggest that galvanized steel sleeves considerably improve thermal insulation and safety. This finding is explained as follows: PVC pipes may burn and break apart at high temperatures, compromising fire compartmentation. A galvanized steel sleeve can retain a burning, broken pipe piece, thereby preventing injuries and stopping the detached pipe from continuing to burn on the ground. Full article

Building materials, including polyvinyl chloride (PVC), play a key role in construction engineering, influencing the durability, esthetics, and functionality of structures. PVC stands out for its lightness, thermal insulation, and corrosion resistance. This makes it competitive with wood, aluminum, or steel, particularly in the manufacture of window joinery. One of the key technological processes in the processing of PVC profiles is welding, the quality of which depends on the precise control of parameters such as the temperature, time, and pressure regulating the speed of the welding heads. In modern welding machines, the use of servo drives guarantees the adequate precision and repeatability of the process, which allows better adjustment to technological requirements than in older machines. This study aimed to determine the effect of the heating head feed rate for selected milling depths on the quality and strength of window frame welds. A criterion in the assessment of the strength of the window frames was the result of failure load tests on the welds. In addition, the tests took into account the quality of the welds. The tests showed that the welding head feed rate of 0.25 mm/s generated the highest-quality welds, taking into account the continuity and symmetry of the weld and its highest failure load. When milling the composite to a depth of 1 mm, the average value of the failure load was 3637 N. Meanwhile, for speeds of 0.19 mm/s and 0.31 mm/s, it was 3157 N and 3033 N, respectively. For the 0.5 mm milling variant and without milling the composite, the average load values were significantly smaller. Full article

In this study, a numerical simulation was used to evaluate the insulation performance of polyethylene (PE) and polyvinyl chloride (PVC) under varied environmental and electrical conditions. Tests were conducted at temperatures of 22 °C and 55 °C, with current levels of 40 A and 60 A, examining key parameters such as electric field intensity, current density, and Joule heating. The results show that, under lower temperature and current conditions, PE demonstrates greater current capacity but suffers from increased Joule heating and energy loss. Conversely, PVC provides more stable insulation with lower energy dissipation. At higher temperatures and currents, PE experiences significant electrical stress and thermal loading, increasing the risk of overheating, while PVC maintains consistent performance. These findings offer valuable guidance for selecting optimal insulation materials in power distribution systems. Full article

This study presents a foam sandwich structure reinforced with carbon fiber columns (FSS-CFC), which exhibits strong mechanical and sound insulation properties. The FSS-CFC consists of two face-sheets and a polyvinyl chloride (PVC) core containing multiple CFC cylinders arranged in a periodic array. The sound transmission loss (STL) measured in acoustic tube experiments closely aligns with the finite element simulation results, validating the reliability of the present research. Through characteristic analyses, the study reveals the sound insulation mechanism of FSS-CFC, identifying three distinct sound insulation dips caused by the standing wave resonance of the core, column-driven same-direction bending vibrations, and column-constrained opposite-direction bending vibrations in the sheets. It is also demonstrated that the sound insulation performance of FSS-CFC is insensitive to hydrostatic pressure changes. Finally, the FSS-CFC is optimized by the genetic algorithm in MATLAB and COMSOL. The optimized FSS-CFC displays good improvements in both mechanical and acoustic performance compared to the initial structure. The average STL in the frequency of 500 Hz to 25,000 Hz has increased by 3 dB, representing an improvement of approximately 25%. The sound insulation mechanism in FSS-CFC could provide valuable insights for the development of a pressure-resistant acoustic structure for use on deep-water vehicles. Full article

The paper examines the use of waste eggshells as a valuable biofiller for modifying plasticized poly(vinyl chloride) (PVC). The raw ES was characterized using TGA, FTIR, particle size analysis, and XRD. The effects of ES on the processing, mechanical and thermal properties, density, porosity, and colour of PVC matrix composites were evaluated compared to pPVC/CC produced using the same methodology. It was found that pPVC/ES exhibits different processing properties to pPVC/CC. The mechanical properties of PVC/ES are slightly lower than those of pPVC/CC at concentrations up to 20 phr. However, at 30 phr and 40 phr, the differences in the mechanical properties of composites with both CC and ES are very similar, and the values are within the designated standard deviation of the measurement. The mechanical properties of PVC/ES do not limit their potential applications. When using eggshell (ES) as a filler, improvements in tensile strength (t_ts) were observed, ranging from 38% to 61% compared to the unfilled matrix and from 35% to 54% compared to pPVC/CC with an equivalent amount of filler. Although ground eggshells have similar insulating properties to calcium carbonate (CC), they are more effective at scavenging chlorine (Cl•) released during the initial stages of decomposition. This effectiveness helps to slow down the breakdown of PVC, as the eggshells maintain their porous, sponge-like structure when used as a filler. Full article

The mature theory of safety assessment and system operation is crucial to ensure the safety and property of commuters under the tunnel fire condition, but the relationship between pollutants and the quality of the luminous environment is still the weakest link in this research area. To establish this close relation, this study adopted three different scaled experiments to investigate the pollutant-visibility model based on spectral analysis. The first scaled tunnel model fire experiment, conducted on a 20.5-m-long experimental platform, utilized three combustion sources to analyze the light attenuation of natural gas, PVC-insulated cables, and smoke cakes based on the APE index. Then the spectrum selective contrast experiment collected several typical spectral data from coloured transparent panels, and the compared results advocated that there is no much different impact on luminous environment with these combustion sources under smoky conditions. At last, the acrylic box pollutant experiment was conducted with different CO/NO₂ concentrations, and the results provided quantitative relationship between the light average attenuation rate and CO/NO₂ concentrations. The findings of this study could be able to further establish the connection between pollutants and safety evacuation, as well as ventilation and luminous environment by combining the relatively mature research of tunnel fire. Full article

A flat-plate unglazed solar water heater (SWH) with a polymer thermal absorber was developed and experimented with. Polymer thermal absorbers could be a viable alternative to metal thermal absorbers for SWH systems. The performance of this polymer SWH system was measured based on inlet and outlet water temperature, water flow rate, ambient air temperature and solar irradiance. The polymer thermal absorbers were hollow Polyvinyl Chloride (PVC) tubes with a 20 mm external diameter and 3 mm thickness and were painted black to enhance radiation absorption. The pipes are arranged in a rectangular spiral inward–outward alternating-flow (RSioaf) pattern. The collector pipes were placed in a 1 m × 1 m enclosure with bottom insulation and a reflective surface for maximized radiation absorption. Water circulated through a closed loop with an uninsulated 16 L storage tank, driven by a pump and controlled by two valves to maintain a mass flow rate of 0.0031 to 0.0034 kg·s⁻¹. The test was conducted under a partially clouded sky from 9 a.m. to 5 p.m., with solar irradiance between 105 and 1003 W·m⁻² and an ambient air temperature of 27–36 °C. This SWH system produced outlet hot water at 65 °C by midday and maintained the storage temperature at 63 °C until the end of the test period. Photothermal energy conversion was recorded, showing a maximum value of 23%. Results indicate that a flat-plate solar water heater with a polymer thermal absorber in an RSioaf design can be an effective alternative to an SWH with a metal thermal absorber. Its performance can be improved with glazing and optimized tube sizing. Full article

Polyvinyl chloride (PVC) resins are widely used in modern society due to their acid and alkali resistance, low cost, and strong insulation properties. However, the high chlorine (Cl) content in PVC poses significant challenges for its recycling. This study reviews the treatment processes, model construction, and economic and environmental assessments to construct a methodological framework for the sustainable development of emerging dechlorination technologies. In terms of treatment processes, this study summarizes three types of processes, pretreatment, simultaneous dechlorination during chemical recycling, product purification, and emphasizes the necessity of dechlorination treatment from a systematic perspective. Additionally, the construction of models for dechlorination processes is investigated from the laboratory to the industrial production system to macro-scale material, in order to evaluate the potential inventory data and material metabolism behaviors. This review also summarized the methodology framework of Techno-Economic Analysis (TEA) and Life Cycle Assessment (LCA), which can be applied for evaluation of the economic and environmental performance of the dechlorination processes. Overall, this review provides readers with a comprehensive perspective on the state-of-the-art for PVC dechlorination technologies, meanwhile offering sustainable guidance for future research and industrial applications of chemical recycling of PVC waste. Full article

The distribution grid comprises cables with diverse constructions. The insulating material used in low-voltage (LV) distribution cables is predominantly PVC. Furthermore, the presence of cables with different structures in the grid poses challenges in detecting the aging of the cable network. Finding a universal and dependable condition-monitoring technique that can be applied to various types of cables is indeed a challenge. The diverse construction and materials used in different cables make it difficult to identify a single monitoring approach that can effectively assess the condition of all cables. To address this issue, this study aims to compare the thermal aging behavior of different LV distribution cables with various structures, i.e., one cable contains a PVC belting layer, while the other contains filler material. The growing adoption of distributed generation sources, electric vehicles, and new consumer appliances in low-voltage distribution grids can lead to short, repetitive overloads on the low-voltage cable network. Hence, these cable samples were exposed to short-term cyclic accelerated aging in the climate chamber at 110 °C. The cable’s overall behavior under thermal stress was evaluated through frequency and time domain electrical measurements (including tan $\delta$ and extended voltage response) and a mechanical measurement (Shore D). The tan $\delta$ was measured in the frequency range of 20 Hz–500 kHz by using the Wayne-Kerr impedance analyzer. The extended voltage response measurement was conducted using a C# application developed in-house specifically for laboratory measurements in the .NET environment. The study observed a strong correlation between the different measurement methods used, indicating that electrical methods have the potential to be adopted as a non-destructive condition-monitoring technique. Full article

In light of terrorist attacks and accidents, the need for structural protection against explosive events has increased significantly in recent decades. Conventional unprotected windows pose a particularly high risk of injury to building occupants due to glass fragments and window frames being propelled into the interior and exterior of a building. This article addresses new experimental research on the protection of conventional single casement windows with insulating glass units (double-paned) and window frames made of un-plasticized polyvinyl chloride (uPVC) against blast loads. Entire window systems were tested in ten shock-tube tests using different retrofit-configurations. The retrofitted protective measures include anti-shatter films and catcher-cable systems. Furthermore, the influence of steel profiles inserted in the window frames is investigated. The applied blast loads met the requirements for ER1-certification according to EN 13541:2012 (tested at a reflected peak overpressure of 66.7 kPa and a reflected maximum impulse of 417.7 kPa∙ms). In the test series, various measurement methods were used to capture the velocity of the window fragments, the dynamic cable forces, and the hazard. The data provide valuable information for the design and implementation of catcher-cable systems for existing buildings, which can improve the occupant safety in the event of an explosion. Full article

The article analyses the impact of wind suction on roof coverings glued with polyurethane adhesives to flat roofs, i.e., roofs with an up to 20% slope. The impact of the cyclical wind was simulated in fatigue tests, gradually increasing the test pressure in repeated sequences until the first delamination occurred. The tests were carried out for eight test sets, with concrete and trapezoidal sheets used as a construction substrate, on whose surface thermal insulation layers were glued with polyurethane adhesive; the thermal insulation layers were EPS (expanded polystyrene) and PIR (polymer mainly of polyisocyanurate groups), respectively, followed by flexible sheets, i.e., a laminated PVC membrane (polyvinylchloride) and an EPDM (terpolymer of ethylene, propylene and a diene with a residual unsaturated portion of diene in the side chain)-type rubber-based membrane. The test results were compared with the functional requirements determined with computational simulation methods for the maximum wind load values on the example of wind loads for Poland. The tests confirmed that some polyurethane adhesives could ensure the operation of flexible sheets used as flat roof coverings that are failure-free from the point of view of resistance to wind suction. Full article

This paper presents the results of a study of the properties of a new composite material made from poly(vinyl chloride) plastisol (PVC) and conifer-derived wood flour. The material can be used for thermal insulation, floor coverings with high resistance to mechanical trauma, and protective coatings. The plastisol was made from emulsion poly(vinyl chloride), the plasticiser was bis(2-ethylhexyl) adipate, and the stabiliser was octyltin mercapeptide. Two types of flour were used: fine-grained and coarse-grained. Its properties, such as bulk density, oil number, and plasticiser number, were determined. The polymer-wood composite contained 20 or 30 wt.% wood flour in PVC. Plastisol was obtained by repeated mixing, mashing, and venting under vacuum. The produced composite material was gelated at temperatures of 130, 150, and 170 °C. The gelation process of the composites was studied in a Brabender apparatus. Samples in the form of polymer films were used to study density, hardness, thermal stability, and mechanical and thermomechanical properties. The structure of the composites was observed by scanning electron microscopy (SEM). A summary of all test results showed that composite films made from PVC plastisol with 20 wt.% of fine wood flour gelled at 150 °C had the most favourable physical, mechanical, and thermal properties. Full article