Application of ionic liquids as a catalyst in the synthesis of polyvinyl butyral (PVB) polymer

In-situ electrospinning PVB/Camellia oil/ZnO-TiO2 nanofibrous membranes with synergistic antibacterial and degradation of ethylene applied in fruit preservation

This work utilizes a handheld electrospinning device to prepare a novel nanofibrous composite membrane in situ for packaging freshness. It can realize pick-and-pack and is easy to operate. The nanofibrous membrane is based on PVB as the matrix material, adding Camellia oil (CO) and ZnO-TiO2 composite nanoparticles (ZT) as the active material. The antimicrobial property of the CO and the photocatalytic activity of the nanoparticles give the material good antimicrobial and ethylene degradation functions. Meanwhile, this nanofibrous membrane has good mechanical properties, suitable moisture permeability and good optical properties. The nanofibrous membrane are suitable for both climacteric and non- climacteric fruits. Its use as a cling film extends the shelf life of strawberries by 4 days and significantly slows the ripening of small tomatoes. Therefore, this nanofibrous membrane has great potential for application in the field of fruit preservation.

Optimization of a polyvinyl butyral synthesis process based on response surface methodology and artificial neural network

High quality polyvinyl butyral (PVB) can be used as the intermediate film of automobile and building glass and the packaging film of photovoltaic cells. Therefore, it is necessary to optimize its synthesis process to obtain suitable products with a high acetalization degree (AD) and small particle size (d _p). In this work, a deep eutectic solvent (DES) was selected as the catalyst, and response surface methodology (RSM) and artificial neural network (ANN) were utilized to optimize the synthesis process of PVB. The concentration of polyvinyl alcohol (A), the dosage of DES (B) and n-butanal (C), and the aging temperature (D) were selected as process variables, and the comprehensive score (AD, d _p and material and energy consumption) was introduced as the response. The results showed that single-factors B, C, D, and the interactions AB, BC and CD had significant effects on the comprehensive score, and the qualified PVB products (AD > 81%, d _p = 3-3.5 μm) were obtained under the optimal conditions obtained by RSM and ANN models. ANN is a better and more precise optimization tool than RSM. Also, DES played a dual role in catalysis and dispersion in the synthesis of PVB and showed good reusability, so it has great application potential in PVB industrial production.

Electrospun Sound-Absorbing Nanofibrous Webs from Recycled Poly(vinyl butyral)

The amount of poly(vinyl butyral) (PVB) foils added to car windscreens to suppress glass shattering represents a huge worldwide volume of the material, and once a vehicle is end-of-life it also becomes a significance contributor to landfill. The recycling of PVB materials from windscreens has been expensive and despite improvements in recycling technologies, the landfill burden still increases. However, an increase in oil prices can shift the economic balance and stimulates the possible applicability of recycled PVB. As PVB is a relatively easy electrospinnable material, it is shown that nanofibrous mats produced from recycled PVB blends in ethanol exhibit very good sound-absorbing properties. To achieve an optimal composition between virgin and recycled PVB blends, a series of their ratios was consecutively characterized using various techniques (rheometry, SEM, FTIR, DSC, TGA, DMA, an impedance tube for determining sound absorbance). The best result was obtained with two wt. portions of 8 wt.% solution of virgin PVB in ethanol and one wt. portion of 12 wt.% solution of recycled PVB in ethanol.

Alkaline Treatment Variables to Characterize Poly(Vinyl Alcohol)/Poly(Vinyl Butyral/Vinyl Alcohol) Blend Films

Novel poly(vinyl alcohol) (PVA)/poly(vinyl butyral–vinyl alcohol) (P(VB-VA)) films with improved hydrophobicity were prepared from poly(vinyl acetate) (PVAc)/poly(vinyl butyral) (PVB) blend films with various mass ratios by saponification in a heterogeneous medium. The successful conversion of PVAc to PVA and PVAc/PVB to PVA/P(VB-VA) films was confirmed by Fourier transform infrared spectrometry, X-ray diffraction, and proton nuclear magnetic resonance analysis. This study also shows that the degree of saponification (DS) depends on the saponification time. The maximum DS of 99.99% was obtained at 96 h of saponification for all films, and the presence of PVB did not affect the DS at saponification times of 48–96 h. The effects of the PVAc/PVB blend ratio before and after saponification were determined by contact angle measurement, and the hydrophobicity was found to increase in both cases with increasing PVB content. Additionally, all the films exhibited improved mechanical properties after saponification, and the treated films possessed an unusual porous and uneven surface, in contrast with the untreated films. The prepared films with improved hydrophobicity can be used for various applications, such as biomaterials, filters, and medical devices.

Optimization of the photocatalyst coating and operating conditions in an intimately coupled photocatalysis and biodegradation reactor: Towards stable and efficient performance

Intimately coupled photocatalysis and biodegradation (ICPB) is an attractive novel technology for the mineralization and detoxification of persistent organics. Good photocatalytic performance is essential for an advanced ICPB operation, and the photocatalyst coating and illumination conditions are strong determining factors. In this work, response surface methodology (RSM) involving the central composite design (CCD) was employed to discover optimal operating conditions, by using tetracycline hydrochloride (TCH) as the model pollutant. Polyvinyl butyral (PVB) was employed to form an adhesion layer, enhancing P25 TiO2 activity and stability. We achieved the optimal coating conditions with a mixing time of 20 h, TiO₂ dosage of 8 g/L, and PVB concentration of 0.5 wt.%. The optimum running conditions for an ICPB-reactor were found to be at a carrier volume ratio of 40% and light intensity of 6000 μw/cm². These conditions were essential for the production of desired intermediates and functional microbial survival. At the optimized parameters ranges, ∼98% TCH removal and ∼40% mineralization was achieved, and the inhibition on Q67 illuminance was only 30.32%. This is the first work on optimizing the fabrication and operation of ICPB, which is meaningful for the application of ICPB in practical engineering.

Carbothermal Reduction Synthesis of Aluminum Nitride from Al(OH)3/C/PVB Slurries Prepared by Three-Roll Mixing

Polyvinyl butyral (PVB) was used in the Al(OH)₃/carbon black/ethanol slurries by the three-roll mixing to prepare AlN powder using the carbothermal reduction–nitridation (CRN) process in the experiments. The effects of PVB addition on the synthesis of AlN powder were studied by viscosity, tap density, XRD, SEM and TG measurements. The results showed that the PVB layer covering on the surface of Al(OH)₃ particles reduced the viscosity of Al(OH)₃/carbon/ethanol slurry and increased the dispersion homogeneity of Al(OH)₃/carbon raw powder. The tap densities of the Al(OH)₃/carbon mixtures after three-roll milling could be increased with the increase in PVB addition. In the CRN process, most of the PVB covering Al(OH)₃ particles evaporated and supplied the passage for nitrogen removal to the particles. Based on the experimental data, the role of PVB on the mixing and CRN process was discussed.

Design and fabrication of in-situ N-doped paper-like carbon nanofiber film for thiophene removal from a liquid model fuel

The novel nitrogen-doped porous carbon nanofibers film (PAN-CNFs) had been successfully prepared by electrospinning with polyacrylonitrile as carbon precursor after calcination under N₂ atmosphere. The structure and physical properties of PAN-CNFs were determined by a series of characterizations. The results showed that the PAN-CNFs-800 have the higher N content (10.02 wt.%), larger surface area (354.327 m²/g) and optional V_mic/V_Total (28.14 %). The adsorption desulphurization was examined by thiophene (TH) simulated oil. The experimental results demonstrated that the PAN-CNFs were the desirable adsorption materials as alternative candidate in present adsorption technique. Furthermore, the pseudo order kinetics and adsorption isotherm of the PAN-CNFs-800 was intensive studied, which exhibited good adsorptive capacity for thiophene (TH) reached 113.33 mg/L according to the Langmuir isotherm model and maintained promising recycling reusing performance. The adsorption mechanism was proposed by these models, which should be attributed to the cooperating effect of the proper pore structure and the π-π complexation interactions.