Huiyu Bai

Mechanical and water barrier properties of soy protein isolate film incorporated with gelatin

Soy protein isolate film modified with gelatin was prepared via solvent casting. The effect of gelatin contents on visual, mechanical, water barrier properties and surface hydrophobicity of the films was investigated. It showed that the film containing 30u2009wt% gelatin had higher tensile strength, elongation at break, contact angle, and lower water vapor transmission rate. Soy protein isolate/gelatin blend film structures were characterized by Fourier transform infrared. Compared with the other films, the 30u2009wt% gelatin composite film peak intensity is stronger at 1380u2009cm−1 and weaker at 1538u2009cm−1, indicating that the strong hydrogen bonding between –COOH in the soy protein isolate film and –NH2 in the gelatin led to exposing the –CH3 groups in the soy protein isolate film. Scanning electron microscopy showed that the 30u2009wt% gelatin composite film phase morphology was much finer than the other films. This confirmed that the 30u2009wt% gelatin soy protein isolate/gelatin composite film has good compatibility. The tests performed showed the potential for gelatin to improve the soy protein isolate film properties. This work provided a new approach to explore such films without plasticizer as biodegradable food packaging.

Rheological and structural characterization of HA/PVA-SbQ composites film-forming solutions and resulting films as affected by UV irradiation time.

Hyaluronan (HA)/poly (vinyl alcohol) bearing styrylpyridinium groups (PVA-SbQ) composites film-forming solutions were prepared by a negatively charged HA and an oppositely charged PVA-SbQ. The rheological properties and structural characterization of HA/PVA-SbQ composites in aqueous solution were investigated. Zeta potential measurements and TEM were utilized to explore the formation of HA/PVA-SbQ complex micelles in aqueous solution. UV spectra and DLS experiments confirmed that the micelles are photo-crosslinkable. HA/PVA-SbQ composites films were prepared by a casting method. The microstructure and properties of the film were analyzed by SEM, optical transmittance, DSC, XRD and tensile testing. The crosslinked HA/PVA-SbQ composites films exhibited higher UV light shielding and visible light transparency and better mechanical and water vapor barrier properties as well as thermal stability than the uncrosslinked HA/PVA-SbQ composites films, indicating the formation of three-dimensional network structure. This work provided a good way for increasing the mechanical, thermal, water vapor barrier, and optical properties of HA materials for the packaging material.

All cellulose composites based on cellulose diacetate and nanofibrillated cellulose prepared by alkali treatment

Cellulose diacetate (CDA) composite films were synthesized by incorporation of nanofibrillated celluloses (NFCs), using a casting/evaporation technique. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) characterization indicated the presence of interaction and certain compatibility between CDA and NFCs. The CDA and NFCs were converted to cellulose II by an alkaline treatment which resulted in the formation of all cellulose composite (ACC) films, as indicated by the FTIR and XRD characterization. Significant changes were observed in their structural, thermal, mechanical, and optical transparency properties. The SEM images revealed the excellent compatibility among the constituents of the ACC films. The tensile strength, Youngs modulus, and strain at break of the ACC films with 15wt% NFCs content were increased to 102.3MPa, 5.8GPa, 14.7% respectively. This work provides a promising pathway for manufacturing high performance ACC materials.

Interpenetrated polymer networks in composites with poly(vinyl alcohol), micro- and nano-fibrillated cellulose (M/NFC) and polyHEMA to develop packaging materials

A novel method for the preparation of composites based on poly(vinyl alcohol) (PVA) and micro- and nano-fibrillated cellulose (M/NFC) is reported. The addition of crosslinking HEMA monomers and a photo-initiator enabled the formation of an interpenetrated polymer network that displayed enhanced interfacial adhesion and dispersion of (M/NFC) in the matrix. Photo-crosslinked PVA/(M/NFC)/polyHEMA composite films produced by casting followed by UV polymerization of HEMA were characterized by using several approaches. These included Fourier transform infrared and UV–Vis spectroscopies, differential scanning calorimetry, X-ray diffractometry, thermogravimetric analysis and dynamic mechanical analysis. The thermo-mechanical and optical properties as well as water absorption and vapor barrier abilities of the developed photo-crosslinked PVA/(M/NFC)/polyHEMA films were measured and the benefit of photo-crosslinking determined. The major degradation peak of photo-crosslinked PVA/(M/NFC)/polyHEMA composites increased substantially compared to that of the PVA/(M/NFC) system (from ~300 to ~350xa0°C). The water vapor permeability of PVA/(M/NFC)/polyHEMA composite films was reduced with HEMA loading (5.44xa0×xa010−11, 5.10xa0×xa010−11, 4.12xa0×xa010−11, 4.31xa0×xa010−11xa0g/mxa0hxa0Pa for 0, 5, 10 and 15xa0% HEMA, respectively). Overall, a new and facile method for the synthesis of PVA/(M/NFC)-based composite networks interpenetrated with cross-linked poly(HEMA) is demonstrated, offering excellent prospects for packaging applications.

Properties of Hyaluronan/Pva-Sbq Composite Films Processed by Casting

In this report, a novel hyaluronan/PVA-SbQ composite film was prepared by casting method. The miscibility and morphology of the films were investigated by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The surface hydrophobicity and the thermal properties of the composite films were examined by contact angle (CA) and thermogravimetric analysis (TGA), respectively. The results showed strong hydrogen bonding interactions and molecular miscibility between the two polymers. A dimerization reaction of SbQ pendant groups in PVA-SbQ chains induced by UV led to the crosslinking of the composite film. The film displayed enhanced tensile strength and slightly weakened elongation at break after being photo-crosslinked. Such film may be a promising material for food or drug packaging applications.

Interfacial Interaction Analysis of Blends of Poly(vinylidene fluoride) and Poly(ethylene–butylacrylate–glycidyl methacrylate) Compatibilized by Poly(butylene succinate): Morphologies, Rheological Behavior, and Mechanical Properties

ABSTRACT Poly(vinylidene fluoride) (PVDF) and poly(ethylene–butylacrylate–glycidyl methacrylate) (PTW) are polymers with weak interfacial adhesion. Blends based on PVDF and PTW (50/50u2009w/w) with poly(butylene succinate) (PBS) (0, 1, 3, 5, 7u2009wt%) are obtained by compression molding. The estimation of interfacial interaction among PVDF, PTW, and PBS and the properties of PVDF/PTW blends are investigated. The optimal content of PBS to form a co-continuous morphology in PVDF/PTW blends is proposed, indicating that the beneficial effect of PBS (7u2009wt%) on interfacial adhesion is observed. Overall, estimating interfacial adhesion is a critical issue for designing PVDF/PTW blend with excellent performance, which has a prospect in coating. GRAPHICAL ABSTRACT

DN strategy constructed photo-crosslinked PVA/CNC/P(NIPPAm-co-AA) hydrogels with temperature-sensitive and pH-sensitive properties

In this paper, poly(N-isopropylacrylamide) (PNIPPAm), polyacrylic acid (PAA), polyvinyl alcohol (PVA) and cellulose nanocrystals (CNC) were used to prepare double-network hydrogels by the photo-crosslinking technology. The results from mechanical and swelling tests indicated that photo-crosslinked PVA/CNC/P(NIPPAm-co-AA) hydrogels exhibited temperature-sensitive, pH-sensitive behaviors and good mechanical strengths. We prepared DN hydrogels, which combined the advantages of PNIPAAm, PAA and photo-crosslinking collectively in the PVA/CNC system, leading to controllable temperature and pH responses and improvement in physical properties. A simple and green method for the preparation of DN hydrogels was demonstrated, offering photo-crosslinked PVA/CNC/P(NIPPAm-co-AA) hydrogels as excellent prospects for applications in the medical field.

Effects of modified nanocrystalline cellulose on the hydrophilicity, crystallization and mechanical behaviors of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Fine dispersion of nanocrystalline cellulose (NCC) in a bacterially synthesized poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) matrix is challenging due to their incompatibility. To improve their compatibility, NCC was first grafted with PHBH, marked as NCC-g-PHBH, using (3-aminopropyl)triethoxysilane (APES) as a coupling agent, leading to a grafting degree of ∼25 wt%. The grafting mechanism and the mechanical and crystallization behaviors of the PHBH/NCC-g-PHBH blends, prepared via solution casting, were systematically investigated. The NCC was uniformly dispersed in the PHBH matrix after grafting with PHBH. As a consequence, the mechanical and crystallization properties of the PHBH were greatly improved in the presence of the NCC-g-PHBH. With the addition of 1.0 wt% NCC-g-PHBH, the Youngs modulus of the PHBH/NCC-g-PHBH blend was increased by 15%, which is further evaluated by the Halpin–Tsai model, while the surface contact angles decreased by 30°. Furthermore, the presence of NCC-g-PHBH copolymers greatly increased the nuclei density and decreased the spherulite size of PHBH without changing the crystal structures. Therefore, this work provided a novel route to prepare fully biodegradable and bio-based PHBH nanocomposites, which may broaden the application range of PHBH.

Polydopamine functional reduced graphene oxide for enhanced mechanical and electrical properties of waterborne polyurethane nanocomposites

Waterborne polyurethane/polydopamine (PDA) functional reduced graphene oxidexa0(WPU/PDRGO) nanocomposites were prepared by in situ emulsification method. The presence of axa0PDA layer and the partial reduction of GO by PDA were confirmed by FTIR, XRD, Raman spectra, and TGA. It was found that the interfacial PDA layers facilitated the dispersion of the PDRGO sheets in the WPU matrix and enhanced mechanical properties of the WPU matrix. The resulting WPU/PDRGO nanocomposite coatings show excellent electrical conductivity (9.9u2009×u200910−6–1.1u2009×u200910−4 Sxa0cm−1) corresponding to a PDRGO content of 1–16xa0wt%. The obtained waterborne polyurethane/graphene nanocomposite dispersions are promising for anticorrosion, antistatic, conductive, and electromagnetic interference shielding coatings.

Interpenetrating polymer networks in polyvinyl alcohol/cellulose nanocrystals hydrogels to develop absorbent materials

Polyvinyl alcohol/cellulose nanocrystals/poly(2-Hydroxyethyl methacrylate) (PVA/CNC/polyHEMA) and PVA/CNC/poly(N-methylenebisacrylamide) (PVA/CNC/polyMBA) hydrogels were prepared by photo-crosslinking followed by freezing/thawing (F-T) cycle and this novel preparation method was reported. The formation of interpenetrating polymer networks (IPN) resulted from the addition of crosslinking HEMA or MBA monomers displayed improved interfacial adhesion. The produced hydrogels were measured by scanning electron microscopy (SEM), real-time fourier transform infrared (RTIR), thermogravimetric analysis (TGA), mechanical, swelling and adsorption tests. The results showed both PVA/CNC/polyHEMA with semi-IPN and PVA/CNC/polyMBA with dual network (DN) hydrogels had higher thermal stability, lower water loss rate and better swelling and reswelling and mechanical properties, comparing to PVA and PVA/CNC hydrogels. The adsorption behaviors of hydrogels using xylenol orange (XO) and methylene blue (MB) as model dyes were evaluated, indicating that PVA/CNC/polyHEMA and PVA/CNC/polyMBA hydrogels could hold some dyes. Overall, this work provided a good way for increasing mechanical, swelling, reswelling, thermal, and adsorption properties of PVA/CNC, which will be a promising water-manageable material for agriculture application and a candidate for dye carrier.