Development of Vitamin C-Loaded Electrospun Nanofibers of Mixture of Polysaccharides of Pullulan/Xanthan Gum for Fast Dissolving Oral Film Applications.

In this study, polysaccharide-based nanofibrous fast dissolving oral films (FDOFs) were developed using pullulan (PUL) and xanthan gum (XG) via electrospinning. The edible, continuous, and bead-free nanofibers with average diameters ranging from 181.17 nm to 260.84 nm were prepared. The morphological, thermal, mechanical, and water-soluble properties of the nanofibrous FDOFs were characterized. For prospective future applications of the developed PUL/XG FDOFs, a model nutrient of vitamin C (VC) was encapsulated into the FDOFs. The success of VC encapsulation was confirmed by Fourier transform infrared spectroscopy. The encapsulation efficiency of VC was above 85% by ultraviolet-visible spectrophotometer. The amorphous structure of PUL/XG in the nanofibers film was demonstrated by X-ray diffractometer. In addition, the edible FDOFs could dissolve in water within 3 s. The nanofibers film we prepared could be used as nutrient or drug carriers and edible packaging film.

Electrospun natural polypeptides based nanofabrics enriched with antioxidant polyphenols for active food preservation.

In order to overcome the environmental problems posed by traditional packaging materials and taking into account the degradation factors, a natural polypeptides-based nanofiber rich in different polyphenols was prepared by electrospinning technique and has been explored as an active food packaging material. The results showed that the introduction of polyphenols improved the hydrophobicity and oxidation resistance of the natural polypeptides based nanofabric. The antioxidant value was 82.5% after incorporation of 15% gallic acid, which was ten times more than that of the natural polypeptides-based nanofabrics without polyphenols. Through the packaging test of wrapped cherries, it was found that the nanofabric films greatly improved the preservation performance of cherries. Water loss, hardness and gas release were significantly enhanced when compared with those of unwrapped cherries. In this work, the zein/gelatin film with 15% gallic acid or 10% procyanidins polyphenols exhibited the best fresh-keeping performance and remarkable effect thus leading to potential application aspect.

Electrospinning of polyvinyl alcohol into crosslinked nanofibers: An approach to fabricate functional adsorbent for heavy metals.

Electrospun nanofibers have a wide range of applications due to their unique miniature size and accompanying ultra-high specific surface area. Polyvinyl alcohol(PVA) is a kind of hydrophilic materials, and hence its nanofiber morphology prepared by electrospinning disappeared after solution immersing. In the present work, crosslinked PVA nanofibers were prepared by electrospinning and then employing glutaraldehyde vapor crosslinking to improve their water resistance and mechanical properties. As an application, these nanofibers were used to adsorb Cu2+ and Pb2+ according to varying crosslinking time and different concentrations of ionic solution. It was observed the crosslinked PVA nanofiber films maintained good fiber morphology after adsorption, while the nanofiber morphology of uncrosslinked samples was lost. The stability of the crosslinked nanofiber films in water was improved, the adsorption equilibrium time of Pb2+ decreased from 30 h to 10 h while the equilibrium adsorption time of Cu2+ decreased from 15 h to 5 h, and the tensile strength of the nanofiber films with crosslinking time of 20 h was 7.99 MPa, which was 240% higher than that of the nanofiber with crosslinking time of 1 h, indicating higher efficiency.

Fabrication, properties and applications of soy-protein-based materials: A review.

The environmental crisis caused by the use of petroleum-based nondegradable polymers and the impending petroleum finite resources have directly threatened human being's sustainable development. Therefore, ecofriendly polymers based on natural renewable resources are attracting more and more attention. As the byproducts of soy oil industries, soy protein, is regarded as a viable alternative for petroleum-based polymeric products. In order to improve the physical properties, especially the mechanical properties and water resistance that limit their extensive applications, different modifications were adopted. Among these efforts, incorporating nanoparticles and blending with other polymers are proved to be effective ways. The properties of the resulting materials are highly dependent on the processing methods, nature of the components, dispersion status and the compatibility. This review intends to provide a clear overview on preparation, properties, and applications of soy-protein-based materials. These biodegradable materials will find more and more potential applications in biodegradable foams, edible films, packaging materials, biomedical materials, etc.

Effect of Sorbitol Plasticizer on the Structure and Properties of Melt Processed Polyvinyl Alcohol Films.

Poly (vinyl alcohol) (PVA) possesses wide applications as food packaging materials, but is difficult to melt process for its strong inter/intra hydrogen bonding. In this work, flexible PVA films with different content of sorbitol plasticizers were prepared by melt processing with the assistance of water. And the influence of sorbitol plasticizer content on the crystallinity, optical transparency, water-retaining capability, mechanical properties, thermal stability and oxygen and water permeability were investigated. The results indicated that sorbitol dramatically improved the melt processing ability of PVA. Sorbitol could interact with PVA to form strong hydrogen bonding interactions, which would decrease the original hydrogen bonding of the matrix, resulting in the decrease of crystallinity degrees. The glass transition, melting and crystallization peak temperatures decreased with the increase of sorbitol. All the films exhibited fine optical transparency. The water retaining capability were improved with the increase of sorbitol. Especially, an increase in elongation at break and decrease in Young's modulus and tensile strength were observed indicating good plasticizing effect of sorbitol on PVA films. In addition, the PVA films prepared in this work exhibited fine barrier properties against oxygen and water, suggesting wide application potential as packaging materials.

Enhanced mechanical and thermal properties of poly (vinyl alcohol)/corn starch blends by nanoclay intercalation.

Poly (vinyl alcohol) (PVA)/corn starch blend films with enhanced properties were fabricated by melt processing and montmorillonite (MMT) reinforcing. It was revealed that strong hydrogen bonding occurred between the abundant OH groups of the matrix and polar SiOSi and OH groups of MMT. The highly exfoliated MMT nanolayers were randomly dispersed in the matrix containing MMT lower than 10wt%, whereas the intercalated structure was predominant with MMT content higher than 10wt%. With the increase of MMT, the glass transition temperature as well as equilibrium torque increased. The water sorption decreased and water resistant properties were improved with the incorporation of MMT due to the restricted swelling of the matrix by MMT nanolayers. Significant improvement in strength and flexibility were observed due to the fine dispersion of the MMT layers and the strong interaction between MMT and the matrix. The thermal stability was also improved. The MMT nanolayers could act as the heat and mass transport barriers and retard the thermal decomposition of the composites.

Fabrication and properties of polyvinyl alcohol/starch blend films: Effect of composition and humidity.

In this work, starch/polyvinyl alcohol (PVA) blend films with different compositions were prepared by melt processing. The effect of the composition and relative humidity (RH) on the structure and properties of the resulting blends were investigated. OH groups on starch and PVA formed hydrogen bonding interactions, which could improve the compatibility of the two components. With the increase of starch, the degree of crystallinity of PVA component decreased. The fracture surface of the blend films exhibited rough surface, suggesting the tough fracture. With the increase of starch, the water uptake at equilibrium decreased. With the increase of RH, the water uptake at equilibrium of the resulting blends increased. The tensile strength, elongation at break and Young's modulus decreased with increasing content of starch. However, at 50% starch content, the flexibility of the blend films was still high, with the elongation at break more than 1000% and tensile strength of 9MPa, which was superior to the commonly LDPE package films. The tensile strength and Young's modulus decreased with the increase of RH, while the elongation at break was enhanced dramatically, indicating the improved flexibility. Therefore, these kinds of blend films exhibited wide application potentials as packaging materials.

Interconnected porous epoxy monoliths prepared by concentrated emulsion templating.

Porous epoxy monoliths were prepared via a step polymerization in a concentrated emulsion stabilized by non-ionic emulsifiers and colloidal silica. A solution in 4-methyl-2-pentanon was used as the continuous phase, which contained glycidyl amino epoxy monomer (GAE), curing agent, and an emulsifier. An aqueous suspension of colloidal silica was used as the dispersed phase of the concentrated emulsion. After the continuous phase was completely polymerized, the dispersed phase was removed and a porous epoxy was obtained. An optimal HLB value of emulsifier for the GAE concentrated emulsion was determined. In addition, the morphology of the porous epoxy was observed by SEM. The effect of the colloidal silica, the emulsifier, the curing of the epoxy, and the volume fraction of the dispersed phase on the morphology of porous epoxy are systematically discussed.