Flexible PVC Research Articles

Stretchable, transparent and multifunctional PVC-gel heater: a novel approach to skin-mountable, wearable thermal devices

Electric heaters based on functional materials and innovative designs have been developed for various applications. In this paper, we propose a soft dielectric heater (SDH) using polyvinyl chloride-gel (PVC-gel) as the dielectric heater and hydrogel as stretchable electrodes. Under an AC voltage, the leakage current in the PVC-gel leads to continuous injection and discharge of charges, causing the polarized plasticizers and flexible PVC chains to vibrate and collide, thereby generating heat through dielectric heating. Furthermore, the SDH generates a uniform temperature distribution even under strains up to 400%. Besides, high transmittance over 86% across the visible range renders it suitable for wearable or skin-mountable heaters from an esthetic viewpoint. Its capacitor-like structure achieves a scalable design, enabling extension from a singular cell to a row/column addressable and pixelated array of heaters. The 5 × 5 SDH array can deliver varied thermal information and sensations while maintaining performance even when stretched.

Reusability of Scrap Rubber, Tire Shredding, Recycled PVC and Fly Ash for Development of Composites with Vibration Damping Ability.

The study focuses on harnessing recycled materials to create sustainable and efficient composites, addressing both environmental issues related to waste management and industrial requirements for materials with improved vibration damping properties. The research involves the analysis of the physico-mechanical properties of the obtained composites and the evaluation of their performance in practical applications. Composite materials were tested in terms of their tensile strength and vibration damping capabilities, considering stress-strain diagrams, vibration amplitudes, frequency response functions (FRFs) and vibration modes. The research results have shown that by adding PVC and FA to the rubber-based matrix composition, the stiffness decreases and elasticity increases. The use of FA in the structure of composite materials causes an increase in the vibration damping possibilities due to the fact that it contributes to the chemical properties of the analyzed composite materials. Additionally, the use of PVC results in increased material elasticity, as evidenced by the higher damping factor compared to materials containing only rubber. Simultaneously, the addition of FA and PVC in specific proportions (60 phr) can lead to a decrease in stiffness and a greater increase in the damping factor. The incorporation of PVC and fly ash (FA) particles into rubber-based matrix composites reduces their stiffness and increases their elasticity. These effects are due to the fact that FA particles behave as extensions of chemical bonds during traction, which contributes to the increase in yield elongation. In addition, the use of flexible PVC increases the elasticity of the material, which is evidenced by the increase in the damping factor.

Effect of partial replacement of antimony trioxide with zinc borate and stannic oxide on the flame retardancy of flexible PVC films

AbstractReplacing antimony trioxide (Sb2O3) with an environmentally friendly alternative is of great scientific and commercial value for studying the flame retardant properties of flexible PVC (fPVC) films in automotive interior materials. This study develops flame retardant fPVC films with reduced Sb2O3 content by introducing stannic oxide (SnO2) and zinc borate (ZB). The results indicate that the fPVC film with ZB partially replacing Sb2O3 exhibits superior flame retardancy and smoke suppression compared to the product containing SnO2. The peak heat release rate (PHRR), total heat release (THR), and total smoke release (TSR) of 2ZB/2Sb2O3 fPVC film are reduced by 32.1%, 27.5%, and 22.1%, respectively, compared to that of 4Sb2O3 contained fPVC film. The increase in flame retardancy is attributed to the presence of ZB, which compensates for the deficiency of char formation ability of Sb2O3 in the condensed phase. The PHRR and THR of 2SnO2/2Sb2O3 fPVC film decrease by 27% and 12.5%, respectively, compared to that of 4Sb2O3 fPVC film, while the TSR increases by 16.5%. This study develops a straightforward approach to creating a flame retardant fPVC film that is suitable for the latest industrial application in automotive interior materials.

Enhancing fire performance and thermal stability of flexible PVC with lanthanum phytate montmorillonite

This study presents a breakthrough approach to enhance the thermal stability, mechanical properties, and flame retardancy of flexible PVC (fPVC). It introduces lanthanide phytate montmorillonite (Pa-La-Mt) as an innovative nanofiller. Pa-La-Mt was synthesized by intercalating sodium phytate and lanthanum chloride into the interlayer space of montmorillonite (Mt), effectively increasing the layer spacing. The analysis of this study, using X-ray diffraction (XRD) and Fourier infrared spectrometer (FTIR), confirmed this structural transformation. The influence of Pa-La-Mt on the structural and performance aspects of fPVC composites was thoroughly examined. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), mechanical testing, limit oxygen index (LOI), and cone calorimeter (CONE) revealed compelling outcomes. Pa-La-Mt not only improved the dispersion and compatibility of Mt. within the fPVC matrix but also enhanced the thermal stability and mechanical performance of fPVC composites. Most notably, Pa-La-Mt exhibited remarkable flame retardant and smoke suppression effects on fPVC composites. It led to a substantial increase in LOI value, a reduction in the peak heat release rate and total heat release amount, and a decrease in CO and CO2 emissions. This underlines Pa-La-Mt as a promising nanofiller with profound implications for various fPVC applications.

Synthesis, characterization and performance evaluation of different alkyl chain lengths flame-retardant plasticizers for poly(vinyl chloride) derived from sustainable vanillic acid

The current market for poly(vinyl chloride) (PVC) plasticizers is dominated by flammable petroleum-based compounds, accounting for over 80 % of the total share. Due to their high flammability, the search for novel approaches to enhance the fire resistance of flexible PVC has gained urgency. However, traditional flame-retardant schemes suffer from shortcomings such as poor compatibility, inferior long-term performance, and weak mechanical properties. Herein, we synthesized a novel biobased flame-retardant plasticizer (VAn-P) using vanillic acid as a skeleton. This plasticizer exhibits remarkable properties, including a substantially lower glass transition temperature compared to unplasticized PVC. The binding energy between VAn-P and PVC is calculated to be –33.30 kcal/mole, indicating a strong interaction. Furthermore, the maximum elongation at break of VAn-P plasticized PVC is 16 times higher than that of unmodified PVC. All PVC samples plasticized with VAn-P achieved a UL-94 VTM-0 rating. TGA-FTIR analysis revealed that the flame-retarding mechanism of VAn-P involves solid-phase action, significantly delaying the dehydrochlorination process of PVC. Moreover, VAn-P exhibits superior migration resistance compared to dioctyl phthalate (DOP). We also investigated the effects of alkyl chain lengths in VAn-P on various properties of PVC blends, including thermal stability, flame retardancy, mechanical properties, and optical performance. The toxicity of vanillic acid-based flame-retardant plasticizer has undergone an initial assessment. Overall, this green plasticizer is expected to endow polymers with high plasticizing performance and flame retardancy, providing a novel and sustainable approach for the synthesis of functional plasticizers.

Improving the flame retardancy and smoke suppression of flexible PVC by incorporating zinc borate‐modified diantimony trioxide

AbstractThe properties and structure of flexible PVC by incorporating zinc borate (ZB)‐modified diantimony trioxide (Sb2O3) were investigated. The results of flame retardancy and smoke suppression testing indicate that there was an obvious maximum Limited oxygen index (LOI) value of PVC/20 wt.% ZB–Sb2O3 composites reached 37.5% and passed the UL 94 V‐0 rating. An obvious synergistic effect between ZB and Sb2O3 was observed by LOI, SDR, and TG. Moreover, remarkable decreases in the smoke density were observed when ZB–Sb2O3 was incorporated into PVC. In addition, the tensile strength and elongation at break of PVC/ZB–Sb2O3 composites was higher than PVC/Sb2O3 composites, and this ameliorative effect was mainly arising from the ZB–Sb2O3 nanoparticles, which reduced the degree of fatal defects on PVC. The addition of ZB and Sb2O3 greatly increased the amount of residual char and apparently improved the mechanical properties of PVC composites. According to scanning electron microscopy photographs of residual char, after thermal decomposition, there were many fragments linked to the condensed phase and the compact char layer. Fourier transform infrared spectroscopy shows the residues char was composed of benzene ring, the flame retardants occurred and the condensed phase with significant interactions.

Oro-ruminal sampling device and technique for rapid collection of rumen content and improved recovery of solid fractions for microbiome analysis.

Rumen fistulation is a widely used procedure that allows for collection of ruminal contents. However, fistulation is an invasive and costly procedure that generally limits the number of animals that can be recruited for experiments, thus encouraging the use of alternative techniques such as the intra-esophageal tube technique. One of the challenges of this technique is the limited ability to collect solid fractions from the rumen content pool which may impact the microbial community structure in the sample, particularly affecting the recovery and characterization of solid adherent-bacteria. We developed an intra-esophageal tube rumen sampling technique and device referred to as ‘Rumen Sampler MG’ with the aim of increasing the recovery of solid fractions from rumen content compared with other oro-ruminal sampling methods. The ‘Rumen Sampler MG’ device consists of a manual pump fitted with a barometer and an intra-esophageal flexible PVC tube with beveled terminal edge allowing for minimal clogging of the sampling tubing and a rapid flux of contents being sampled. Nine lactating Holstein-Friesian dairy cows (554.6 ± 25.2 kg BW; 8.3 ± 3.3 DIM) were recruited to evaluate the proposed method. During the procedure, animals were safely restrained in a chute and administered with a low dosage of a neuroleptic drug to reduce animal stress during sampling. An endoscopic camera was inserted into the reticulo-rumen through the esophagus to identify the sampling location and determine the length of the sampling tube necessary to reach the desired location. Following, the intra-esophageal sampling tube connected to a manual pump was inserted for collection of rumen contents. Samples collected did not present visual evidence of saliva contamination (e.g., high viscosity) and their pH ranged within expected values (6.33 - 7.04) for samples collected from the reticulo-rumen. Each sample contained 35–40% wet solids volume. Individual dry matter intake and milk production of cows continued to increase after sampling as expected for cows in the early postpartum period, suggesting that the sampling procedure did not affect cow performance. Results from microbiome analysis of rumen content samples suggest that the relative abundances of the main bacterial phyla are consistent with those from samples collected from dairy cows via rumen fistula in previous studies. The device and technique proposed allow for adequate samples of ruminal liquid and solid contents to be collected for microbiome analysis without disruption of animal performance.

Design, Fabrication, and Application Study of Droplet Tube Based Triboelectric Nanogenerators

The invention of triboelectric nanogenerators (TENGs) provides an effective approach to the sustainable power of energy. Liquid-solid interface-based TENGs have been researched in virtue of less friction for harvesting energy from raindrops, rivers, and oceans in the form of water flows. However, TENGs based on droplet tubes have been rarely investigated. In this study, we proposed a new droplet tube-based TENG (DT-TENG) with free-standing and reformative grating electrodes. Both straight and curved DT-TENGs have been designed and fabricated including straight and curved TENG at different inclination angles. The electric properties of DT-TENGs have been evaluated and different materials and hydrophobicity treatments for the tubes have been studied. Initial studies on different liquids demonstrated significant electricity output differences to recognize polar and nonpolar solvents. This DT-TENG was also made into a smart fishing float that can recognize different movement speeds brought about by different weights and generate corresponding electric signals to remind the angler. Furthermore, flexible PVC helix TENG demonstrated similar performance under both straight and helix situations. This study provides a foundation and academic insight into the design and fabrication of droplets based TENGs for energy harvesting in smart cities.

Effect of Bi2O3 nanostructures on X-ray shielding, thermal, mechanical and biological properties of PVC polymer nanocomposites

The effect of Bi2O3 nanoparticles and nanowires as fillers in flexible PVC composites was investigated on the shielding properties against X-ray radiation at radiodiagnostic energies (50–129 kV). The PVC composites were gamma radiation cross-linked at 75 kGy. Materials were characterized by thermal analyses, and microstructure studied by SEM. The evaluation involved attenuation measurements and toxicity through cell viability assay. The mechanical properties and toughness were highly improved, according to DMA results, and the TGA analysis shows a small influence of the Bi2O3 nanostructures in the dehydrochlorination reaction of PVC during its thermal decomposition. Moreover, SEM images show a uniform distribution of the Bi2O3 nanostructures in the PVC matrix. Attenuation measurements showed low levels of X-ray transmission for PVC composites with 50 %wt of Bi2O3 and a mass attenuation coefficient greater than those reported for lead in the energy ranges studied, which is an improvement with the use of Bi2O3 NWs. In addition, PVC composites show low HVL and TVL values, making them feasible for the attenuation property. Density measurements show that the composites are lighter than lead. No-toxicity was observed for these composites through cell viability assay. Therefore, the investigated PVC composites are suitable for preparing new radiation-attenuating materials using Bi2O3 NWs.

Flexible Poly(vinyl chloride) with Durable Antibiofouling Property via Blending Star-Shaped Amphiphilic Poly(ε-caprolactone)-block-poly(methacryloxyethyl sulfobetaine).

Flexible poly(vinyl chloride) (PVC) plastics have been widely used in medical devices, but the preparation of antibiofouling flexible PVC materials that can maintain their antibiofouling performance when suffering deformation is still a challenge. In this work, we synthesized a series of amphiphilic star-shaped three-arm block copolymers SPCL-b-PSB, consisting of hydrophobic inner blocks poly(ε-caprolactone) (PCL) and hydrophilic outer blocks poly(methacryloxyethyl sulfobetaine) (PSB). Then, flexible PVC films were prepared by blending SPCL-b-PSB with PVC and plasticizer. Benefiting from the specific star-shaped topological structure of SPCL-b-PSB, hydrophilic PSB blocks of the copolymer could efficiently migrate to the surface of the film via annealing treatment, which give the film surface excellent hydrophilicity, while the latch-like entanglements between hydrophobic PCL blocks and PVC give the hydrophilic surface excellent stability. Antibiofouling properties of the blended films were investigated. The optimized blended film could reduce ∼94% of bovine serum albumin adsorption, ∼ 87% of lysozyme adsorption, and ∼89% of platelet adhesion and resist bacterial adhesion effectively. What is more, the blended films could maintain their antibiofouling performance when suffering stretching, rubbing, or bending. More than 86% of bovine serum albumin adsorption could be reduced, even when the film was stretched by 50%. This work provides a new strategy for the preparation of durable antibiofouling flexible plastics.

The influence of material properties and process parameters on energy consumption during extrusion of flexible PVC

The aim of this work is to investigate the correlation between the process settings, the material properties, and the extrusion energy consumption. Experiments were conducted on a laboratory extruder, testing different flexible PVCs. During continuous single-screw extrusion for various process conditions, power signals were recorded for the extruder's motor and the entire machine. According to the results of the previous works, the absorbed current, the power factor, and the total active power increased with the screw speed for all the tested materials. However, due to the high content of additives, the considered materials exhibited wall-slip during extrusion, and the influence of the slip behavior on the specific energy consumption was evaluated too. It was found that the specific energy consumption did not decrease monotonically with the screw speed, and thus the maximum energy efficiency can not always be achieved at the highest screw speed. Significant correlations were found between the material's hardness, viscosity, and process energy usage, with the hardest and most viscous materials requiring more energy to be extruded.

Synthesis, characterization and performance evaluation of a flame retardant plasticizer for poly(vinyl chloride) derived from biobased vanillic acid

The utilization of biobased resources presents a novel approach for the development of high-performance plasticizers with exceptional flexibility. Nevertheless, the combustibility of flexible poly(vinyl chloride) (PVC) products containing high content plasticizers is frequently disregarded. The development of PVC functional plasticizers requires careful consideration of a good balance between flame retardancy, migration resistance and plasticity through molecular structure design. Currently there is a dearth of biobased plasticizers that exhibit exceptional comprehensive properties. Therefore, a novel biobased flame-retardant plasticizer (VA8-P) has been synthesized from vanillic acid and fully characterized using NMR, IR and MS. The VA8-P plasticized PVC exhibits a lower glass transition temperature and higher low temperature resistance, while its elongation at break is 1141.6% higher than unmodified PVC. Transmittance, haze, cross-sectional SEM and 2D/3D AFM all demonstrate its good optical properties and the compatibility of the plasticizer with polymer matrix. PVC plasticized using VA8-P exhibits better hydrophilicity and especially superior migration resistance than does the same polymer plasticized using DOP. The thermal stability and char residue rate for decomposition of VA8-P plasticized PVC are better than the same parameter of material plasticized with DOP. In cone calorimeter tests, VA8-P plasticized PVC showed excellent heat barrier effect. Additionally, PVC-P3 reached the UL-94 VTM-0 level in the vertical burning test. Its flame-retardant mode of action was also verified by TGA–FTIR analysis. A functional biobased plasticizer with excellent comprehensive properties has been synthesized. This material exhibits greater flexibility than many traditional flame-retardant additives and its use can be expected to improve the fire resistance of flexible PVC.

RCS reduction effect based on transparent and flexible polarization conversion metasurface arrays

In recent years, radar cross section (RCS) reduction techniques based on electromagnetic absorption materials have become a hot research topic in the field of electromagnetic stealth. This paper proposes a transparent conformal encoded metasurface based on polarization rotation units. The metasurface array is optimized using the whale optimization algorithm to construct a 1-bit polarization rotation encoded unit array. The proposed metasurface array exhibits good RCS reduction and electromagnetic wave polarization conversion performance in the frequency range of 13.2–20.7 GHz. The RCS reduction effect of the metasurface array is effective at different angles and polarization states. The metasurface is composed of transparent and flexible materials, namely ITO, PET, and PVC plastic. It exhibits conformal properties while maintaining a high physical transmittance of up to 83.6%. The RCS reduction performance of the metasurface is studied under different curvatures and demonstrates good conformal scattering characteristics. The RCS variation of ITO material compared to traditional metallic materials was also analyzed. It was found that ITO with low surface resistance is an effective means to broaden the RCS bandwidth. This makes it suitable for theoretical research and the design of electromagnetic stealth for electronic devices such as radars and antennas with different curvatures.

New Vegetation Monitoring Field Tools Improve Plot Demarcation Consistency

The Heartland Inventory and Monitoring Network uses a scaled plot design for vegetation monitoring. Redesign of aging field plot frames resulted in easier to use equipment. The new designs were aimed at improving measurement precision to reduce sources of nonsampling relocation error. Although sampling sites are permanently monumented at the corners, the center point of subplots is measured from these fixed corners. Increasing confidence in long-term monitoring data through consistent plot deployment will increase the value of that data. The 1 m2 circular plot uses flexible PVC tubing with a PVC pipe inserted and fastened for deployment or coiled for transportation. The redesigned 10 m2 plot delineation device for woodlands utilized a swivel mounted on a threaded rod. Upgrades to aging field gear improved field operations by increasing precision during plot deployment.

Concerning partial discharge detection in cable lines using high-frequency sensors

Partial discharges result in cable line faults that can occur in defective insulation systems made of rubber, polyethylene, XLPE, and flexible PVC. Insulation defects may occur due to disruptions in their production process, cable installation, and operational conditions. Therefore, the diagnostic and monitoring of partial discharge occurrence in cable insulation help prevent emergencies in damaged cable line sections. Partial discharge registration is a non-destructive diagnostic method that helps assess the cable line condition and localize the detected defects. There are various methods of operational monitoring and partial discharge cause analysis based on operative partial discharge sensors. The assessment of cable line condition depends on the efficiency of signal detection and processing by the sensors used. This article reviews the problems of detecting and localizing partial discharges in cable lines and junction boxes using HFCT and UHF sensors. Having analyzed the capabilities of these sensors, we believe that the combined usage of HFCT and UHF sensors is the best method of detecting and localizing partial discharge within the entire cable system (lines and junction boxes).

Circular economy without chemicals controls? Evidence of recirculated toxic plasticizers in flexible PVC products

The global push towards a circular economy (CE) has led to increasing efforts to improve resource utilization efficiency, including plastics recycling. However, the presence of additives, especially those that are toxic, complicates plastics recycling in several ways. Without sufficient controls, the spread of hazardous additives via recycling activities represents a significant public health challenge, particularly among developing nations. This study demonstrates evidence of such uncontrolled recycling, based on an investigation of four household flexible PVC product groups available in Thailand. A versatile pyrolysis/thermal desorption gas chromatography-mass spectrometry (Py/TD-GC-MS) method was employed to simultaneously screen 18 target plasticizers in these products. Di-(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DINP) are the most frequently detected primary plasticizers. DEHP is dominant in vinyl boots, flooring sheets, and hoses, while DINP is dominant in cable sheaths, likely due to a spill-over effect from the EU Restriction of Hazardous Substances (RoHS) directive. Chlorinated paraffins (CPs) are secondary plasticizers that are also detected in most samples, except for boots. The other plasticizers detected include other ortho-phthalates and non-phthalates. These results provide insight into combinatory patterns of plasticizer ‘cocktails’, that comprise restricted, as-yet-unrestricted, and non-restricted plasticizers, embedded in the same individual samples, with a maximum of seven plasticizers found in a single cable sheath. These findings indicate the existence of potentially risky recycling practices that target embedded plasticizers to save cost, without due consideration of their inherent toxicity. Proper interventions are necessary to ensure that CE and chemical safety can be synergized.

Improving the Long-Term Performance of Poly(Vinyl Chloride)

Since neat PVC is rigid, in all applications a plasticizer is added. Migration of the plasticizer results in brittleness of flexible PVC and environmental pollution. We have used three types of cross-linking agent blended with commercial PVC, plasticizer and thermal stabilizer. Heat treatments at 100С, 121С and 136C were performed. We made tensile tests, dynamic friction tests, wear rate determination, scratch resistance determination, water absorption tests and SEM analysis – to make selection of compositions suitable for sufficient cross-linking for long term applications.

Poly(vinyl chloride), a historical polymer still evolving

Poly(vinyl chloride) (PVC) is one of the commodity polymers of the highest worldwide consumption still in continuous evolution. The recent demonstration of the adaptability of this material for extrusion-based 3D printing techniques opens the possibility of manufacturing a large-scale of tailored flexible and ductile PVC objects, apart from those already registered in the market. The most important characteristics of this polymer from a scientific and technological point of view are described here; i.e., some figures and facts concerning the production and applications and, the two main drawbacks of the polymer: thermal degradation and plasticizer exudation. The most recent efforts and advances to overcome polymer limitations and develop new fields of applications based on modification reactions, in solution, at the surface and in the melt state, as well as the use of PVC formulations in the emerging processing technology of additive manufacturing are addressed.

Plasticizing and thermal stabilizing effect of bio‐based epoxidized cardanol esters on PVC

AbstractPoly(vinyl chloride) (PVC) is a widely used plastics in different industries. It is an intrinsically hard and brittle polymer and requires the use of plasticizers to improve the processability. Commonly used phthalate‐based plasticizers have serious toxicity issues and we present alternatives based on epoxidized soybean oil (ESO) and epoxidized cardanol esters (ECEs). ECEs are synthesized from cardanol and three fatty acids (oleic, ricinoleic, and myristic) using 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC) as a coupling agent. Their structure and purity are confirmed by Fourier transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance. Moreover, plasticized PVC films are prepared using a solvent‐free method. The replacement of 10 phr of ESO with 5 phr of ECE improves the plasticizing power due to the co‐solvency effect. Mechanical properties and thermal stability of plasticized PVC films are correlated with the chain length and the number of epoxy groups in ECE. The best plasticizing effect is observed for epoxidized cardanol‐myristate (ECD‐MA). ECD‐MA as a shorter‐chain secondary plasticizer is more compatible with ESO and allows higher conformational mobility of PVC chains. PVC/30ESO/5ECD‐MA polymer exhibits an exceptionally high initial thermal decomposition temperature (314.4°C) while preserving moderate ductility and tensile strength (263.4% and 23.3 MPa). Overall, this study highlights the potential applicability of ECD‐MA in combination with ESO as a sustainable, bio‐based plasticizer and heat stabilizer for flexible PVC products.

On the Stability and Turbulences of Atmospheric-Pressure Plasma Jet Extracted From the Exit of a Long Flexible PVC Tube

Atmospheric-pressure plasma jet (APPJ) created in helium was extracted far from its electrical discharge ignition using a conductor wire inside a flexible plastic tube. The effects of the geometrical parameters of the setup, helium flow, and the applied discharge voltage on the extracted plasma jet characteristics were investigated. It appears that increasing voltage and/or gas flow leads to the augmentation of the jet length. However, in certain combinations, turbulences of the plasma plume may occur. The turbulences threshold may be shifted by changing voltage or tube diameter. Moreover, increasing the tube and wire length induces more dielectric losses along the tube and adds extra impedance to the reactor leading to jet length retraction.