Improving the Photostabilization of Poly(vinyl chloride) Using 4-(benzylideneamino)benzenesulfonamide Tin Complex

The photostabilization of poly (vinyl chloride) (PVC) film filled with an organotin complex in its structure was examined and compared with the blank PVC film. The organotin (IV) complex that contains 4-(benzylideneamino) benzenesulfonamide as a ligand was synthesized and applied as a PVC photostabilizer. The impact of the complex on the polymer was assessed by comparing the properties of the films with and without the complex, before and after irradiation, using Fourier transform infrared spectroscopy, weight loss, viscosity change, atomic force microscopy, and field emission scanning electron microscopy (FE-SEM). Results showed that the complex film had lower weight loss, gel content, and molecular weight deterioration than the plain PVC film. Also, surfaces of the complexes-filled films were smoother, less lumpy, and more homogeneous. These findings were obtained via the FE-SEM and light microscope images and confirmed by measuring the roughness factor. The organotin (IV) complex proved its activity in delaying the photo-degradation of PVC by several mechanisms. Ultimately, the Tin complex has effectively protected the PVC film against irradiation. The photostabilization of poly (vinyl chloride) (PVC) film filled with an organotin complex in its structure was examined and compared with the blank PVC film. The organotin (IV) complex that contains 4-(benzylideneamino) benzenesulfonamide as a ligand was synthesized and applied as a PVC photostabilizer. The impact of the complex on the polymer was assessed by comparing the properties of the films with and without the complex, before and after irradiation, using Fourier transform infrared spectroscopy, weight loss, viscosity change, atomic force microscopy, and field emission scanning electron microscopy (FE-SEM). Results showed that the complex film had lower weight loss, gel content, and molecular weight deterioration than the plain PVC film. Also, surfaces of the complexes-filled films were smoother, less lumpy, and more homogeneous. These findings were obtained via the FE-SEM and light microscope images and confirmed by measuring the roughness factor. The organotin (IV) complex proved its activity in delaying the photo-degradation of PVC by several mechanisms. Ultimately, the Tin complex has effectively protected the PVC film against irradiation.

Construction of mammographic findings simulators to study the interference of silicone implants in the diagnosis of breast cancer

Introduction: Breast cancer is the most prevalent malignant neoplasm among women, presenting itself, in 99% of cases, in females. Augmentation mammoplasty is the most performed aesthetic surgical intervention in the world. Objective: This study aims to improve the search for biomaterials compatible with mammographic findings suggestive of malignancy, to further study the interference of silicone implants in mammography exams. Methods: To make the simulators of mammographic findings, a bibliographic study of possible biomaterials that presented compatibility with the breast tissue and with possible neoplastic findings was carried out. The validation process of the simulators made in this work was carried out in two stages. Results: The result found was a density variation between 2.54 and 2.57 (dimensionless unit). For the second plate, the individual optical density of each material was analyzed. The results found for fiberglass ranged between 1.95 and 2.63. For chicken eggshells between 0.59 and 0.80. For the glycerin suppository, values between 1.43 and 2.29 were found. And for plastic PVC film 1.78 to 2.53. Conclusion: Given the above, it is observed that the first plate as a whole is compatible with mammographic studies. However, on the second plate, when the materials were analyzed separately, it was observed that fiberglass and plastic PVC film were the closest to compatibility with the commercial phantom, being compatible materials to simulate breast neoplasms in possible further studies.

Reconstruction of Lamb Wave Dispersion Curves in Different Objects Using Signals Measured at Two Different Distances

The possibilities of an effective method of two adjacent signals are investigated for the evaluation of Lamb waves phase velocity dispersion in objects of different types, namely polyvinyl chloride (PVC) film and wind turbine blade (WTB). A new algorithm based on peaks of spectrum magnitude is presented and used for the comparison of the results. To use the presented method, the wavelength-dependent parameter is proposed to determine the optimal distance range, which is necessary in selecting two signals for analysis. It is determined that, in the range of 0.17–0.5 wavelength where δcph is not higher than 5%, it is appropriate to use in the case of an A0 mode in PVC film sample. The smallest error of 1.2%, in the distance greater than 1.5 wavelengths, is obtained in the case of the S0 mode. Using the method of two signals analysis for PVC sample, the phase velocity dispersion curve of the A0 mode is reconstructed using selected distances x1 = 70 mm and x2 = 70.5 mm between two spatial positions of a receiving transducer with a mean relative error δcph=2.8%, and for S0 mode, x1 = 61 mm and x2 = 79.7 mm with δcph=0.99%. In the case of the WTB sample, the range of 0.1–0.39 wavelength, where δcph is not higher than 3%, is determined as the optimal distance range between two adjacent signals. The phase velocity dispersion curve of the A0 mode is reconstructed in two frequency ranges: first, using selected distances x1 = 225 mm and x2 = 231 mm with mean relative error δcph=0.3%; and second, x1 = 225 mm and x2 = 237 mm with δcph=1.3%.

Simultaneous Measurement of Thickness and Elastic Properties of Thin Plastic Films by Means of Ultrasonic Guided Waves

Ultrasonic guided waves are already used for material characterization. The advantage of these waves is that they propagate in the plane of a plate and their propagation characteristics are sensitive to properties of the material. The objective of this research was to develop an ultrasonic method that could be used to measure the properties of thin plastic polyvinylchloride films (PVC). The proposed method exploits two fundamental Lamb wave modes, A0 and S0, for measurement of a thin film thickness and Young’s modulus. The Young’s modulus is found from the measured phased velocity of the S0 mode and the film thickness from the velocities of both A0 and S0 modes. By using the proposed semi-contactless measurement algorithm, the Young’s modulus and thickness of different thickness (150 µm and 200 µm) PVC films were measured. The uncertainty of thickness measurements of the thinner 150 µm PVC film is 2% and the thicker 200 µm PVC film is 3.9%.

Polyvinyl Chloride Biodegradation Fuels Survival of Invasive Insect Larva and Intestinal Degrading Strain of Klebsiella

Microbial degradation of polyvinyl chloride (PVC) is eco-friendly and economically attractive, but extremely challenging due to the lack of mechanistic understanding on the degrading strains and enzymes. Motivated by an accidental discovery that the larva of an agricultural invasive pest, Spodoptera frugiperda, effectively survived solely on PVC film, we profiled the intestinal microbiota of S. frugiperda and screened for PVC-degrading strains. The results showed PVC film feeding significantly changed the larvae intestinal microbiota through selective enrichment of Enterococcus, Ochrobactrum and Klebsiella. From the larva intestines, we isolated and named a biofilm-forming strain EMBL-1, and experimentally verified it as the first Klebsiella bacterium that can actively degrade and utilize PVC based on various classic physicochemical and morphological analyses. We further used multi-omics analyses that complementarily integrate whole genomic, transcriptomic, proteomic, and metabolic insights to identify enzyme-coding genes responsible for PVC degradation and proposed a putative biodegradation pathway by the bacterial strain. All in all, both S. frugiperda and its intestinal strain EMBL-1 are discovered to effectively survive on PVC film by exploiting its polymer as a sole energy source. Moreover, this work exemplifying PVC biodegradation provides reference for discovering more degrading microbes and enzymatic resources of other recalcitrant plastics.

Repackaging Nitrite-embedded Dark-Cutting Steak in Aerobic Polyvinyl Chloride Film Decrease Surface Redness

Theoverall goal was to evaluate the effects of repackaging nitrite-embeddeddark-cutting steaks in polyvinyl chloride (PVC) film on surface color.Dark-cutting beef strip loins (n = 8; pH = 6.39) and USDA Low Choice beef striploins (normal-pH, n = 6) were selected at a commercial packing plant.Dark-cutting loins were bisected and randomly assigned to nonenhanceddark-cutting and enhanced dark-cutting with glucono delta-lactone and rosemarytreatments. Normal-pH and nonenhanced dark-cutting steaks were vacuum packaged (VP)and served as controls, while enhanced dark-cutting steaks were packed innitrite-embedded packaging (NP). Steaks from nonenhanced normal-pH in VP, non-enhanceddark-cutting-VP, and enhanced dark-cutting-NP loins were randomly assigned to3, 6, or 9 d of dark storage. Following dark storage, steaks were repackaged inPVC and displayed for 6 d. The instrumental color, visual color, and aerobicplate count were evaluated for all steaks.  Enhanced dark-cutting steaks in nitritepackaging increased (P < 0.05) a* values and nitric oxide myoglobincontent during 24 h of dark storage. Enhanced dark-cutting steaks packaged inNP had greater a* and L* values (P < 0.05) than nonenhanced dark-cutting-VP steaks during darkstorage. Upon repackaging the enhanced dark-cutting steaks from nitritepackaging, nitric oxide myoglobin decreased (P < 0.05) during the first 12 h of display. Loss of nitric oxidemyoglobin corresponds with a darker red appearance, increased surfacediscoloration, and decreased a*values. There were no differences (P> 0.05) in aerobic plate count between enhanced dark-cutting-NP and non-enhanceddark cutting VP steaks during 9 days of dark storage. In conclusion, NPimproved surface redness; however, repackaging enhanced dark-cutting from NP steaksin PVC decreased color stability and redness of dark-cutting beef. 

Pitting corrosion and crevice corrosion behaviors of titanium alloy overlapped with aluminized PVC film in neutral salt spray

This paper presents a research on the corrosion behavior of Ti-15-3 alloy overlapped with aluminized PVC film in salt spray. It was found that severe corrosion occurred on aluminized PVC film in the coupled regions because of crevice corrosion and/or galvanic corrosion whereas Ti-15-3 alloy in the coupled regions experienced minor corrosion. Scanning electron microscope and Energy-dispersive X-ray spectroscopy analyses demonstrated the corrosion products adhered to the surface of Ti-15-3 alloy within the crevice. To evaluate the effect of aluminized PVC film on the crevice corrosion of Ti-15-3 alloy in salt spray condition, it is necessary to compare with the corrosion resistance of Ti-15-3 overlapped with polytetrafluoroethylene (PTFE) in different neutral salt spray. Further, the tests were performed by electrochemical impedance spectroscopy and potentiodynamic polarization. Combining the graphical model, an in-depth understanding of the crevice and galvanic corrosion mechanism of Ti-15-3 alloy overlapped with aluminized PVC film has been revealed.

Functional potential and food safety of fresh-cut ‘Paluma’ guava under edible coatings

Guava is a fruit rich in antioxidants and its value can be enhanced by fresh-cut processing, which increases convenience for consumption. The objective of this study was to evaluate the changes in bioactive compounds, total antioxidant activity (TAA) and microbial quality in slices of fresh-cut (FC) ‘Paluma’ guava coated with chitosan at 2% (Q), calcium chloride at 1% (CC), calcium chloride at 1% + sodium alginate at 1% (CC + A), calcium chloride at 1% + chitosan at 2% (CC + Q), and control (T - without coating). Coated slices were packed in trays, wrapped with PVC film and kept at 3 ± 1 °C and 75 ± 4% RH for 12 days and evaluated for ascorbic acid, lycopene, β-carotene, total extractable polyphenols (TEP), and TAA by ABTS+- and DPPH . Ascorbic acid content of slices did not differ by coatings, but TEP was higher in slices coated with Q. The TAA by DPPH was higher in slices coated with Q, however, by ABTS+- it was higher in those coated with Q, CC and CC + Q. No thermotolerant coliforms or Salmonella were detected in FC guava from any treatment. However, slices coated with Q showed the lowest counts of total coliforms and molds and yeasts. Therefore, the application of Q coating provided microbiological safety to FC guava, still maintaining the levels of bioactive compounds and TAA superior to the control slices, which can characterize this as a healthy FC product, with superior functional potential.