Polyvinyl Alcohol-polyethylene Research Articles

Effect of Incorporating Cellulose Nanofibers and Lemongrass Essential Oil in Polyvinyl Alcohol-Polyethylene Glycol/Glycerin Hydrogel for Wound Dressing

Effect of Incorporating Cellulose Nanofibers and Lemongrass Essential Oil in Polyvinyl Alcohol-Polyethylene Glycol/Glycerin Hydrogel for Wound Dressing

Structural and Optical characterization of gamma irradiated PVA-PEG/Cr2O3nanocomposite films

Polyvinyl alcohol-Polyethylene glycol/Chromium oxide nanocomposite (PVA-PEG/Cr2O3NCP) was synthesized by means of the thermolysis and casting procedures. The NCP films were irradiated with various X-ray dosages (15–130 kGy). The resultant outcome of the X-ray irradiation on the structural and optical characteristics of the NCP films were explored applying X-ray diffraction and UV spectroscopy. The optical band gap, refractive index, Urbach energy and optical dielectric parameters were characterized and interpreted based on the X-ray dosage. The optical bandgap dropped from 3.91 to 2.7 eV for a X-ray dosage of 130 kGy, accompanied with a rise in Urbach energy of the samples. We attribute this to the dominance of crosslinking. Additionally, the color differences between the pristine and the irradiated samples were characterized. The pristine NCP film was uncoloured. It exhibited noteworthy color changes during the X-ray irradiation, as the color intensity reached a value greater than 5. This is an acceptable match in commercial reproduction on printing presses.

In-situ preparation of MIL-88A(Fe)/MIL-100(Fe)/PVA-Co-PE nanofiber membranes for efficient photocatalytic reduction of CO2

In this paper, we tend to ready a polyvinyl alcohol-polyethylene (PVA-Co-PE) composite nanofiber membrane catalyst decorated by bimetallic organic framework MIL-100(Fe)/MIL-88A(Fe). The experimental results of the performance of photocatalytic reduction of CO2 show that it exhibits glorious photocatalytic activity for the reduction of CO2 underneath actinic ray irradiation, and also the best conversion rate of CO2 is 8.3 mL/h. Through SEM, XRD, BET, DRS, FTIR, and alternative characterization ways, the factors touching the photocatalytic CO2 reduction method of the composite nanofiber membrane were investigated. Studies have found that the bimetallic framework structure increases the photocurrent density and significantly reduces the photoluminescence intensity. The versatile composite nanofiber membrane has high photocatalytic activity and smart reusability and features a smart prospect within the photocatalytic reduction of CO2 treatment.

In-situ preparation of MOFs/SiC/PVA-Co-PE nanofiber membranes for efficient photocatalytic reduction of CO2

In this paper, we prepared a polyvinyl alcohol-polyethylene (PVA-Co-PE) composite nanofiber membrane catalyst decorated by Fe-MOFs/SiC and completed the photocatalytic reduction of CO2 performance. The results show that the CO2 conversion rate of composite film materials under visible light irradiation is increased by 31 times compared with powdered Fe-MOFs/SiC materials. Through SEM, XRD, BET, FTIR, DRS and other characterization methods, the influencing factors of the photocatalytic CO2 reduction process of the composite nanofiber membrane were investigated. The synergistic effect of Fe-MOFs/SiC and nanofiber membrane photocatalysis is beneficial to electron-hole pairs. The effective separation and strong absorption in the visible light region make it exhibit excellent photocatalytic activity in the photocatalytic CO2 reduction reaction.

Homogeneous and Heterogeneous Solid State Self-Healing System

The solid state self-healing system was obtained by employing a thermosetting epoxy resin, into which a thermoplastic is dissolved. The aim of this study is to investigate the homogeneous and heterogeneous solid state self-healing system by using thermoplastics comprised of poly(bisphenol-A-co-epichlorohydrin) (PDGEBA), polyvinyl chloride (PVC), polyvinyl alcohol (PVA), polyethylene (PE) and polypropylene (PP) as healing agents. PDGEBA produced homogenous resin blend which undergone random molecule diffusion healing process. A heterogeneous resin blend composed of 8 wt.% PVC, PVA PE, and PP, yielding a “bricks and mortar” morphology wherein the epoxy phase exists as a matrix (mortar) interpenetrated with a percolating thermoplastic (bricks). The healing process in heterogeneous resin blend is attributed to volumetric thermal expansion of healing agent above its melting point in excess of epoxy brick expansion. Healing was achieved by heating the fractured resins to a specific temperature; above their glass transition temperature ( Tg) which obtained from dynamic mechanical analysis (DMA) in order for diffusion process and thermal expansion to occur. The thermal properties and bonding formed in the epoxy resins were characterized by means of Fourier Transform Infrared Spectroscopy (FTIR) and dynamic mechanical thermal analysis (DMTA). Izod impact test and compact tension test were conducted to demonstrate details self-healing capability of different specimens. Results of Izod impact test are in agreement with the result of compact tension test. Under compact tension test, the healable resin with PDGEBA has the highest healing efficiency of 60% followed by PVC, PP, PE, and PVA with 39%, 37%, 28% and 21% of average percentage healing efficiencies in three healing cycle respectively. Morphological studies using optical microscope verified the fracture-healing process and morphological properties of the resins.

Electrical studies on PVA-PE copolymer

The electrical transport properties including electrical conductivity (σ), dielectrical constant (ϵ′), thermally stimulated depolarization current (TSDC), and pyroelectric coefficient (P) of a poly(vinyl alcohol)-polyethylene (PVA-PE) copolymer were studied in the temperature range 296–433 K. Two stages of behavior have been observed with activation energies 1.49 and 0.05 eV. Discussion of conduction mechanism was carried out in terms of relevant theories. The existence of a relaxation peak in ϵ′ versus T relation has been analyzed taking into consideration space charge effects and dipole orientation phenomena. The TSDC spectra showed two peaks with differing intensity and position independent of field intensity. Pyroelectric current data provide further support to space charge effects. © 1997 John Wiley & Sons, Inc.