Our sharp tactile sense is largely attributable to an undulating layer of microstructures between the epidermis and dermis, amplifying tactile signals. Taking inspiration from the biological ...template, we propose a design of flexible capacitive pressure sensors with various microstructural dielectric middle layers, fabricated using a casting-based approach. This is the first confirmed use of microstructural polyvinyl chloride (PVC) gel in dielectric layers and the first example of casting in the fabrication of capacitive sensors. Notably, on account of its flexibility, the sensor also addresses the problem of microstructure fracture and misalignment during sensor bending. These sensors can achieve a maximum sensitivity of 1.34 kPa−1 (under 10 kPa) with a fast response time (50 ms), good cyclic stability (> 1000 cycles), and a wide pressure sensing range (0 ∼ 290 kPa). When attached to a cup or balloon, this study reveals that these sensors can detect the weight and rigidity of the objects, demonstrating their potential in human-machine interaction, as well as in wearable applications.
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•Capacitive sensors with morphology-controllable polyvinyl chloride (PVC) gel dielectric middle layers are first proposed.•The maximum sensitivity is up to 1.34 kPa−1, the widest pressure sensing range (0∼290 kPa), and the response is 50 ms.•The 3D-printed mask coating polyvinyl alcohol (PVA) enables stable microstructural dielectric layer manufacturing.•The fully interlinked design improves sensors’ stability in performance with bending angles up to 120◦.
•The differences on pyrolysis of PVC polymer and plastics were studied for the first time.•More Cl distributed in the pyrolysis char of PVC pipes compared to that of PVC polymer.•Additives in PVC ...plastics promoted the cracking of heavy fraction in pyrolysis tar.
The organic and inorganic additives in PVC plastics cause great difficulties in their actual recycling process, which are different from pure PVC polymer (PVC-PO). In this study, PVC-PO and two commercial PVC plastics were selected and their differences in structure, pyrolysis behavior, chlorine release and migration were compared by FTIR, TG-MS and a fixed-bed pyrolysis reactor. There were more oxygen-containing functional groups and aromatic compounds in the commercial PVC plastics than PVC-PO because of the addition of foaming agents, flame retardants and lubricants. The thermal weight loss of the commercial PVC plastics was divided into three stages due to the decomposition of additives and the releases of CO2 gas, while that of the PVC-PO was two. The pyrolysis tar of two PVC plastics contained 35.72% and 15.71% oxygenated compounds, respectively, while that obtained from PVC-PO contained 96.46% of aromatic compounds. In addition, calcium additives in PVC plastics could promote the cracking of heavy constituents in the volatile, which was favorable for the formation of more light fractions in tar. The pyrolysis gas of PVC-PO was mainly composed of H2 and C1-C4 hydrocarbon gases, while that of PVC plastics contained about 50% of CO2, followed by H2 and hydrocarbon gases. The chlorine content of the PVC-PO (55.88 wt.%) was higher than that of the PVC plastics (13.83 wt.%, 22.77 wt.%). Most of the chlorine in the three PVC samples released as HCl at 220–370 °C, while the peak temperature of dechlorination of the PVC-PO delayed about 8 °C compared to that of PVC plastics and small part of HCl also released at around 475 °C in the pyrolysis of PVC-PO. About 99.90 wt.% of the chlorine was distributed in the gas phase after PVC-PO pyrolysis, while there were 99.85 wt.% and 97.85 wt.% of chlorine was detected in the gas products of two PVC plastics.
Triboelectric-electromagnetic hybrid nanogenerator (HNG) exhibits exceptional output performance, rendering it a highly viable solution for powering tiny electronics in the foreseeable future. ...However, the construction of a simple structure and light weight HNG using magnetizable triboelectric materials is a highly desirable yet challenging task. Herein, we present a HNG based on flexible neodymium iron boron/polyvinyl chloride (Nd2Fe14B/PVC) composite films for efficiently harvesting mechanical energy from the environment. By embedding Nd2Fe14B powder in PVC matrix, the as-prepared Nd2Fe14B/PVC composites possess desirable triboelectricity and magnetic strength, which is advantageous in replacing traditional heavy magnets to construct a lightweight HNG with high performance. Under a force of 3.8 N and a frequency of 2.1 Hz, the triboelectric nanogenerator (TENG) produces an output power of 4.5 mW at a loading resistance of 5 MΩ, while the electromagnetic generator (EMG) generates up to 0.11 mW at a loading resistance of 200 Ω. The HNG exhibits superior stability and better charging performance compared to single energy harvesting units. A commercial 470 μF capacitor can be charged to 3 V within 385 s through the HNG, which can continuously supply electrical energy to a hygrothermograph and vernier scale. This work provides an effective method for preparing magnetizable triboelectric materials and introduces new possibilities for the rational design of simple structure and lightweight HNGs.
A light-weight and stable hybridized triboelectric-electromagnetic nanogenerator with high-performance is designed based on flexible neodymium iron boron/polyvinyl chloride (Nd2Fe14B/PVC) composite film, which can continuously provide electrical energy for a hygrothermograph and vernier scale. Display omitted
•Design a simple and lightweight hybridized triboelectric-electromagnetic nanogenerator remains a challenge.•The novel magnetizable triboelectric film exhibits desirable triboelectricity and magnetic strength.•A hybridized nanogenerator is constructed based on flexible magnetizable Nd2Fe14B/PVC film.•The hybridized nanogenerator can continuously power a hygrothermograph and vernier scale.•This work provides an effective method for preparing magnetizable triboelectric materials.
•Quantitative analysis about char yield of plastic pyrolysis.•Role of intermolecular chlorine loss on char precursor formation during PVC pyrolysis.•Enhancement of char precursor formation using ...reactive transition metal oxide NiO.
Owing to the importance of controlling the decomposition products of plastic pyrolysis, in this study the mechanisms of char formation in the thermal decomposition of PVC were investigated quantitatively using a kinetic approach. Thermal decomposition behavior of pure PVC, PE, PP, and mixtures of PVC + NiO and PVC + TiO2 powders was probed using a thermogravimetry-differential scanning calorimetry analyzer under an Ar atmosphere from room temperature to 1073 K. Morphological and structural analyses of solid residues were conducted using X-ray diffraction, scanning electron microscopy-energy dispersive spectrometry and Raman spectroscopy. Chlorine was removed from PVC up to 673 K with an activation energy of 104.7 kJ/mol, resulting in 38 % mass of solid residue polyene. When temperature was further increased, the decomposition of polyene occurred almost in the same temperature range of PE and PP decomposition, leading to the final solid residue at 1073 K of 11 %, nil and 1 % for PVC, PE and PP respectively. Central to our examination, two competing routes of chlorine loss in the pyrolysis of PVC (involving intramolecular and intermolecular intermediates respectively) were compared, with respect to their contributions towards char formation. By juxtaposing the pyrolysis behavior of PVC against those of PE and PP, it was deduced that chlorine loss through intermolecular intermediates contributed overwhelmingly to char precursor formation. Theoretical calculations revealed around 35 % of PVC subject to pyrolysis underwent chlorine loss via intermolecular intermediates. This theoretically derived proportionality is in good agreement with experimental results, which indicated a char yield of 28.6 % in the thermal decomposition of PVC. This char formation mechanism was further confirmed by the co-pyrolysis results of PVC with each of two transition metal oxides, i.e. chemically reactive NiO and inactive TiO2, showing that the intermolecular chlorine loss was enhanced in the presence of NiO due to the formation of NiCl2, whereas no obvious change in char yield was observed in case of TiO2 because no chlorination of TiO2 was detected. This combination of experimental and theoretical considerations unanimously verifies that intermolecular mechanisms of chlorine loss in the pyrolysis of PVC play a leading role to the formation of net structures giving rise to char. These findings allude to the possibility of manipulating the decomposition products such as to synthesize net structured carbon based materials through the pyrolysis of waste plastics.
Gamma irradiation exhibits a complex influence on the properties of PVC/PANI/TiO2 nanocomposite films. XRD analysis reveals a non-monotonic response in crystallinity, with an initial increase at ...lower doses due to crosslinking followed by a decrease at higher doses attributed to polymer chain scission. Mechanical properties exhibit an improvement in tensile strength and Young's modulus at moderate doses (up to 100 kGy) due to crosslinking. However, excessive irradiation (>100 kGy) induces chain degradation, causing a decrease in both tensile strength and elongation at break. Similar dose-dependent behavior is observed in thermal properties, with moderate doses improving thermal stability and melting temperature before a decline at higher doses due to chain degradation. Gamma irradiation significantly affects AC conductivity, suggesting potential changes in structure, charge carrier density, and conduction mechanisms. While the core chemical structure remains largely unaffected, FTIR and UV–Vis spectroscopy analyses indicate alterations in the degree of crosslinking and optical properties, warranting further investigation. Refractive index increases with irradiation due to enhanced density and changes in polarizability. This study highlights the importance of tailoring the gamma irradiation dose to achieve desired properties in PVC/PANI/TiO2 nanocomposite films for various applications.
•γ-Irradiation tailors crystallinity of nanocomposites.•Moderate doses enhance strength & stiffness.•Optimized thermal stability for heat resistance.•Tuned electrical conductivity for electronics.•Balanced optics for light & refractive index.
•PVC microplastics affected the arm regeneration efficiency of Ophiactis virens.•PVC microplastics damaged Xenopus laevis intestines and its swimming behaviour.•In consideration of both models, ...adverse effects were recorded starting from 1 μg mL−1.•The results suggest the combined use of classic and unconventional toxicity models.•Classic toxicity protocols should incorporate histological and behavioral analyses.
In this study, we investigated the effects of PVC microplastics (PVC-MPs) using two different animal models: the brittle star Ophiactis virens, and the African clawed frog Xenopus laevis. This is the first study using an environmental relevant sample of PVC-MPs obtained through mechanical fragmentation of a common PVC plumbing pipe. Exposure experiments on brittle star were performed on the adult stage for a duration of 14 days, while those on African clawed frog were performed on the embryogenic developmental stage according to the standardized FETAX protocol (Frog Embryo Teratogenesis Assay-Xenopus). For both models, different endpoints were analysed: mortality, developmental parameters, behavioural assays and histological analyses on target organs by optical and electronic microscopy. Results showed that the concentration of 0.1 μg mL−1 PVC do not cause any adverse effects in both models (common NOEC concentration), while exposure to 1 μg mL−1 PVC adversely affected at least one species (common LOEC concentration). In particular arm regeneration efficiency was the most affected parameters in O. virens leading to a significantly lower differentiation pattern at 1 μg mL−1 PVC. On the contrary, in X. laevis larvae histopathological analyses and behavioural tests were the most susceptible endpoints, exhibiting several abnormal figures and different swimming speed at 10 μg mL−1 PVC. Histopathological analyses revealed a higher abundance of degenerating cells, pyknotic nuclei and cellular debris in the gut of exposed larvae in respect to control. The comparative analyses performed in this work allowed to characterize the specificity of action of the PVC-MPs on the two species, underlining the importance of exploring a large spectrum of endpoints to offer adequate protection in the emerging fields of microplastic research.
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•Flexible PVC materials suffer from migration of their additives.•Plasticizers covalently bound to the polymer chain avoid migration.•Oligomeric caprolactone additives are prepared by ...ring-opening polymerization.•An industrially viable sustainable way for plasticization is described.
Oligomeric plasticizers for PVC were synthesized using ring-opening-polymerization of caprolactone (CL) initiated by aromatic and heteroaromatic thiol compounds containing hydroxy groups. The obtained plasticizers were chemically bound to the polymer both, in solution and in the melt, with different PVC/plasticizer weight ratios and their efficiency with respect to the degree of anchorage, resistance to migration and plasticization were studied.
Thiolates from heteroaromatic thiol plasticizers were too strongly basic and produced partial hydrolysis and transesterification side reactions during the anchorage reaction to the polymer. On the other hand, oligomers carrying an aromatic thiol end group could be bound selectively and without hydrolysis to the PVC chains. The most suitable system was produced on a 50 kg scale and the plasticized materials obtained were analysed showing good degrees of anchorage and excellent plasticizing properties.
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.
•We present Pa-La-MMT, a green flame retardant from nature, making fPVC safer in an eco-friendly way.•Adding Pa-La-MMT makes fPVC more heat-resistant and stronger, closing the gap between fire safety and structure.•Pa-La-MMT excels as a flame retardant, raising LOI significantly and earning a top V-0 rating in UL-94 tests.
