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The development of a seed coating with micronutrient release system is of extreme research importance for sustainable agriculture. In this work, a zinc release system was developed, using zinc-loaded PVA/Zein nanofibers. Solution blow spinning was used to produce nanofibers (average diameter of approximately 160 nm), as demonstrated by field-emission scanning electron microscopy (FE-SEM), with some bead presence, which served as main zinc reservoir, as evidenced by energy-dispersive X-ray spectroscopy (EDX). Biodegradation assay showed the biodegradability of the PVA/Zein nanofibers with over 30% mass loss after 31 days, an important and desired ability for the proposed application. Encapsulation efficiency of the nanofibers was measured at more than 90%. The release profile of zinc-loaded nanofibers was observed to be a two-step release, with an initial burst release (approximately 52% in 3 h) followed by a slow release (approximately 6% in 189 h), which is related to the zinc reservoir in the nanofibers that was observed by EDX and is a profile that is advantageous for the proposed application. Germination assay shows that the seed coating applied to the soybean seeds was effective, with the zinc released from the nanofibers being absorbed by the seeds and, acting as fertilizer, improved some of the analyzed parameters (approximately 24, 59 and 127% increase in shoot length, α-chlorophyll and zinc content, respectively). Results demonstrated that zinc-loaded PVA/Zein nanofibers are a promising material for to be used as seed coating, being able to improve crop performance. [ABSTRACT FROM AUTHOR]

Solution blow spinning (SBS) is used to make poly(butylene‐adipate‐co‐terephthalate) (PBAT) and poly(vinylpyrrolidone) (PVP) blend nanofibers and study the effect of process parameters on their formation. A 34–1 fractional factorial statistical model with three levels and four factors was applied. The factors included the concentration of PVP (wt%) in the PBAT polymer matrix, pressurized air pressure (psi), working distance (cm), and feed rate (ml h−1). The linear and quadratic effects were analyzed using a Pareto chart and verified in a well‐adjusted response surface model. The PVP concentration and working distance had a significant effect on the production of nanofibers. The nanofibrous mats were evaluated by scanning electron microscopy (SEM) and had a mean diameter ranging from 164 to 656 nm. A higher concentration of PVP and a shorter working distance resulted in lower mean fiber diameter. In addition, X‐ray diffraction revealed an increase in the degree of crystallinity of the nanofibrous PBAT due to a greater degree of packing among the polymer molecules. However, the addition of PVP to the polymer matrix is associated with a reduction in the degree of crystallinity of the nanofibrous mat. [ABSTRACT FROM AUTHOR]

ABSTRACT Poly(lactic acid) (PLA) fibers has been obtained by solution blow spinning (SBS) using different solvents, however most of them are toxic and can be dangerous to human health or cause harm to the environment. Therefore, this work aimed to evaluate the use of dimethyl carbonate (DMC), a greener solvent, on the production of PLA fibers by SBS using surface response analysis to evaluate and compare the influence of three solvents (chloroform, DMC, and 1,1,1,3,3,3-hexafluoro-2-propanol, HFP) in the average fiber diameter. Scanning electron microscopy (SEM) was used to analyze the fiber morphology and different ranges of fiber diameter was observed when varying the solvents (chloroform: 260-970 nm; DMC: 240-650 nm; and HFP: 220-470 nm). Regression analysis showed the polymer concentration was significant for all solvents and the air pressure was significant when using chloroform and HFP. Regardless of the air pressure, increasing the PLA concentration increased the average fiber diameters for all solvents. Chloroform and HFP indicated a tendency of reduction on the average fiber diameter when the air pressure was decreased, however this behavior was not observed for DMC. It was also observed that the standard deviation indicated to be more affected by the polymer concentration than by the air pressure. The results also indicated that lower surface tension and viscosity can reduce fiber thickness. All solvents showed to be feasible to produce PLA fibers by SBS and DMC can be used to produce PLA fibers with an affordable price using a greener process. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43379. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate the effect of three silane coupling agents with different aliphatic chain lengths on the hydrophobicity of eucalyptus pulp fiber. The three silanes coupling agents used (isobutyltrimethoxysilane, methyltrimethoxysilane, and n-octyltriethoxysilane [OTES]) were each tested at three concentrations. Scanning electron microscopy coupled with energy dispersive spectroscopy revealed that the silane coupling agents markedly increased the Si content of the treated fibers. The Si distribution was not completely homogenous but was abundant in the treated samples. The treated fibers had higher contact angles for water and lower moisture adsorption than the control. Of the coupling agents tested, OTES treated fibers had the highest moisture resistance. This was likely due to the greater chain length of the aliphatic side group coupled to OTES. The use of silane coupling agents with alkyl side chains could improve the functional properties of pulp fiber and increase its compatibility with hydrophobic polymers. POLYM. ENG. SCI., 55:1273ȓ1280, 2015. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The aim of this study was to produce nanostructured poly (lactic acid) (PLA) mats incorporated with the 1-MCP/α-CD complex (F 1-MCP) by the solution blow spinning (SBS) technique and to apply them as a nano-sachet emitting 1-MCP in a banana packaging system. The nanofibers that comprise the mats presented uniform morphology with diameters between 157 and 184 nm. Scanning electron microscopy showed that crystals of 1-MCP/α-CD were encapsulated and found on the nanofibers' surface, changing their thermal properties and contact angles. The release of 1-MCP gas from the nano-sachet of nanostructured PLA mats with encapsulated 1-MCP/α-CD was proven based on the delay of banana ripening during storage (21 °C and 90 % RH). Therefore, the nanostructured PLA mats with encapsulated MCP/α-CD, produced by SBS, proved viable and applicable in packaging systems that aim to delay ripening and increase the postharvest shelf life of climacteric fruit, such as bananas. [ABSTRACT FROM AUTHOR]