Blend Films Research Articles

Candida Antarctica Lipase B-assisted top-down visualization of surface morphology of poly(ε-caprolactone)/poly(ethylene oxide) blend films

A series of enzymatic degradation experiments were designed to examine the surface morphology of phase separated poly(ε-caprolactone) (PCL)/poly(ethylene oxide) (PEO) blend films. Candida antarctica Lipase B (CALB), previously reported to have superior degradation selectivity when used at low concentrations, was utilized to selectively dissect interlamellar amorphous PCL chains and therefore to reveal the crystalline region of PCL phase. Water soluble PEO can be simultaneously removed by the CALB aqueous solutions, allowing one to envision the topological features of phase separated PCL/PEO films with various blend ratios. The transition of phase-separated PCL/PEO from nucleation and growth to spinodal decomposition was fully mapped out, along with the spatial distribution and surface morphological features of the crystalline PCL phase. The morphological characteristics of PCL/PEO blend films were further correlated to their reported physicochemical properties, demonstrating the impact of microscopic structures on the macroscopic properties of given semicrystalline polymer systems.

Active packaging films based on poly(butylene succinate) films reinforced with alkaline halloysite nanotubes: Production, properties, and fruit packaging applications

Alkaline treated halloysite nanotubes (aHal) were introduced into poly(butylene succinate) (PBS) matrix using melt blending and solvent casting techniques to enhance the functional properties. The films were characterized for morphological, thermal, mechanical, antibacterial, barrier, and ethylene scavenging properties for their fresh food packaging use. The films exhibited ethylene scavenging performance because of the increased lumen diameter of aHal. The highest ethylene scavenging performance was achieved at 5 wt% aHal (5-aHal) loading for both production methods. The amount of ethylene in the gas-tight container decreased by 80% and 75% in the presence of extruded and solvent-cast 5-aHal, respectively. While PBS/aHal films have mechanical properties comparable to other films recommended for food packaging, extruded films were more flexible and durable than solvent-cast films. In addition, extruded films were found to have a higher water vapor barrier. A packaging test has also been carried out on sliced tomatoes and apples stored at room conditions for 7 days. 5-aHal films showed the best performance in extending the fruit's shelf life. Considering all the results, the melt blending films offer superior performance. Bio-based PBS/aHal films have the capability to contribute significantly to the food safety by serving as eco-friendly, active food packaging materials.

The effect of polylactic acid-based blend films modified with various biodegradable polymers on the preservation of strawberries

Polylactic acid (PLA) has garnered much attention in the field of fruit and vegetable packaging. Despite its poor flexibility and water resistance, PLA film faces challenges in being used for strawberry storage and freshness preservation due to its inability to maintain flavor quality. In this study, a series of PLA-based modified films was produced by melt blending and extrusion cast processing with PLA as the main component, along with flexible biodegradable polyesters or polycarbonate as the secondary component. First, five different biodegradable polymers were used to investigate the effect of the flexibility and barrier properties of different dispersed phases on the morphology, mechanical properties, and water vapor barrier of PLA-based blend films. Next, the impact on the freshness of strawberries was assessed through examination of fruit color and weight, as well as the levels of O2 and CO2 in the packaging bags. The results showed that the size of the dispersed phase and interfacial bonding with PLA were the key factors determining the mechanical and barrier properties of the blend films. The PLA-polycaprolactone (PCL) blend showed the best compatibility among them, with PCL having the smallest dispersion size (D=0.58 µm), higher toughness than the other four PLA blends, and greater enhancement of PLA. Additionally, it exhibited a similar rate of quality loss in strawberry preservation compared to commercial PE. As a result, the color and luster were more completely preserved. The results of this study may help the future development of degradable plastics, to reduce environmental pollution.

Influence of ZnMn2O4/CuCo2O4 nano-fillers on the optical and electrical properties PVA/CMC/PEG blended polymers

(1-x)ZnMn2O4/xCuCo2O4 samples were synthesized by the co-precipitation method while polyvinyl alcohol/carboxymethyl cellulose/polyethylene glycol (PVA/CMC/PEG) blended polymer were fabricated by the casting method. Rietveld refinement analysis was used to determine the crystallite size and phase percentages for each composition were determined for all samples. The morphology and structure of PVA/CMC/PEG/(1-x)ZnMn2O4/xCuCo2O4 blends were examined using scanning electron microscopy and x-ray diffraction techniques. The reflectance and transmittance spectra were examined for blended polymers using a diffused reflectance spectrophotometer. Using LCR meter, the prepared blend films' dielectric properties were evaluated. When the blend is loaded with 0.9ZnMn2O4/0.1CuCo2O4, the lowest transmittance values (29–47 %) in the visible region are reached. As the CuCo2O4 doping levels became 10 % in the filler, the smallest direct and indirect energy gap values of 5.4 and (4.47, 1.9, 1.65) eV were attained, respectively. The linear and nonlinear optical parameters affected by the amount of CuCo2O4 in the filler samples. The optical conductivity of the doped blend reached its maximum value at x = 0.15. The CIE chromaticity diagrams revealed that the blends have varying degrees of blue color. The addition of (1-x)ZnMn2O4/xCuCo2O4 fillers improves the energy storage capability of the blends without raising the energy dissipation. The highest value of AC conductivity was achieved with the blend containing 0.9ZnMn2O4/0.1CuCo2O4. Nyquist plot revealed that the ionic conductivity increased as a result of doping. The obtained results suggest that the doped PVA/CMC/PEG/(1-x)ZnMn2O4/xCuCo2O4 blends might be used in a variety of industrial applications, including solar cell technology.

PHYSICO-CHEMICAL CHARACTERISTICS OF OSA-STARCH ISOLATED FROM BASMATI RICE AND ITS UTILIZATION IN ETHYLENE GLYCOL PLASTICIZED PVA BLEND FILMS

In the current research, basmati rice starch (BRS) has been modified with octenyl succinic anhydride (OSA). The properties of BRS and modified basmati rice starch (MBRS) were evaluated, and subsequently, the effect of their addition to polyvinyl alcohol (PVA) in two different ratios (70/30 and 30/70) to prepare blend films was studied. The degree of substitution of MBRS was 0.00483%, which was found within the permitted range of Food and Drug Administration guidelines. The pH (6.1 vs. 5.8) and viscosity average molecular weight (1.5 × 104 and 1.275 × 104 Da) were found to be lower for MBRS, solubility (11.52 vs. 13.60%), swelling power (11.5 vs. 13.60 g/g), and oil absorption (2.4 vs. 3.2 g/g) capacities were higher. FTIR and XRD studies revealed minor differences in the MBRS spectra owing to the low substitution. The blend films cast with PVA and MBRS showed higher film thickness, hydration characteristics, transparency, and UV-blocking efficiency.

Thermal, Morphological, Mechanical, and Biodegradation Properties of Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)/High-Density Polyethylene Blends.

Polymer blends of poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) (PLLA-PEG-PLLA) and high-density polyethylene (HDPE) with different blend ratios were prepared by a melt blending method. The thermal, morphological, mechanical, opacity, and biodegradation properties of the PLLA-PEG-PLLA/HDPE blends were investigated and compared to the PLLA/HDPE blends. The blending of HDPE improved the crystallization ability and thermal stability of the PLLA-PEG-PLLA; however, these properties were not improved for the PLLA. The morphology of the blended films showed that the PLLA-PEG-PLLA/HDPE blends had smaller dispersed phases compared to the PLLA/HDPE blends. The PLLA-PEG-PLLA/HDPE blends exhibited higher flexibility, lower opacity, and faster biodegradation and bioerosion in soil than the PLLA/HDPE blends. Therefore, these PLLA-PEG-PLLA/HDPE blends have a good potential for use as flexible and partially biodegradable materials.

Preparation and characterization of conjugated PVA/PANi blend films doped with functionalized graphene for thermoelectric applications

Flexible nanocomposite thick films consisting of PVA0.7PANi0.3 polymer blend doped with different concentrations of nanoplatelets functionalized Graphene (NPFGx) (where x = 0, 5, 10, 15, 20, and 25 wt.%) were fabricated using the solution cast technique. Scanning electron microscopy (SEM), X-ray diffractometer (XRD), energy dispersive spectroscopy analysis (EDX), and Fourier-transform infrared spectra (FT-IR) were used to study the structure of the samples. The results showed that the ordered structure, its orientation, the PANis' well dispersion, and the electrostatic forces play a significant role in enhancing the interfaces between the polymer blend and the NPFG. Thermogravimetric analyses (TGA) and Thermoelectrical analyses (TE) showed that the PVA-PANi conducts a promised conjugated blend for thermoelectric applications. The introduction of the NPFG contents into the blend increased the TE measurements as the DC electrical conductivity ≈ 0.0114 (S cm−1), power factor ≈ 3.93 × 10–3 (W m−1 K−2), and Z.T. ≈ 8.4 × 10–7, for the 25 wt.% NPFG nanocomposite film. The effect of the polymers’ phonon contribution in the thermal conductivity controlling and enhancing the thermal stability of the prepared nanocomposite films.

Mechanical, thermal and biodegradation studies of highly degradable composite films of pectin/guar gum/ polyvinylpyrrolidone with rice crop residues: a future vision of packaging and mulch films

ABSTRACT In the present work, eco-friendly composites were fabricated using pectin/guar gum/ polyvinylpyrrolidone blend as matrix and agriculture waste like rice husk and rice straw as reinforcements. Rice husk and rice straw are treated with an alkali solution and then incorporated into the matrix by solvent casting method. The amount of rice husk/rice straw varied from 5% to 15% of the total polymer content. The interaction between polymers and reinforcements is studied by FTIR which shows the presence of hydrogen bonding among the components. SEM images were used to confirm the homogeneous distribution of rice husk/rice straw in the composite films. Thermogravimetry analysis of the composites and the control (blend) film shows that there is an improvement in thermal degradation stability upon the incorporation of reinforcements. The tensile strength of composites is also augmented when compared with the control film (24.61 MPa) and the composite with 10% rice husk has a maximum (29.41 MPa) tensile strength. The biodegradation study of the composite films is performed by the soil burial method.

The Conjugated/Non-Conjugated Linked Dimer Acceptors Enable Efficient and Stable Flexible Organic Solar Cells.

The fabrication of the flexible devices with excellent photovoltaic performance and stability is critical for the commercialization of organic solar cells (OSCs). Herein, the conjugated dimer acceptor DY-TVCl and the non-conjugated dimer acceptor DY-3T based on the monomer MY-BO are synthesized to regulate the molecular glass transition temperatures (Tg) for improving the morphology stability of active layer films. And the crack onset strain values for the blend films based on dimer acceptors are superior than that of small molecule, which are beneficial for the preparation of flexible devices. Accordingly, the binary device based on PM6:DY-TVCl achieves a maximum power conversion efficiency (PCE) of 18.01%. Meanwhile, the extrapolated T80(time to reach 80% of initial PCE) lifetimes of the PM6:DY-TVCl-based device and PM6:DY-3T-based device are 3091 and 2227h under 1-sun illumination, respectively, which are better than that of the PM6:MY-BO-based device (809h). Furthermore, the flexible devices based on DY-TVCl and DY-3T exhibit the efficiencies of 15.23% and 14.34%, respectively. This work affords a valid approach to improve the stability and mechanical robustness of OSCs, as well as ensuring the reproducibility of organic semiconductors during mass production.

Intelligent Food Packaging: Quaternary Ammonium Chitosan/Gelatin Blended Films Enriched with Blueberry Anthocyanin-Derived Cyanidin for Shrimp and Milk Freshness Monitoring.

Blueberry anthocyanin-derived cyanidin (BAC) was used to prepare a series of responsive food freshness packaging films by compounding it with quaternary chitosan (QC) and gelatin (G). The fundamental properties, pH sensitivity, and functional attributes of the films were examined. The BAC solutions exhibited notable variations in color (from red to pink to violet) under different pH conditions. The incorporation of BAC resulted in improved UV-vis shielding capabilities but compromised the mechanical strength of the films (with tensile strength values from 85.02 to 44.89 MPa, elongation at break from 13.08% to 3.6%, and water vapor transmission rates from 5.24 × 10-9 to 7.80 × 10-9 g m-1 s-1 Pa-1). The QC-G-BAC films, containing 5-15 wt% BAC, exhibited noticeable color changes in acidic/ammonia environments within a short timeframe, easily discernible to the naked eye. Furthermore, the inclusion of BAC significantly enhanced the antioxidant and antimicrobial properties of the films. The addition of 5-15 wt% BAC to QC-G-BAC films could be employed for assessing the freshness of fresh shrimp (from red to dark red) and pasteurized milk (from red to dark earthy yellow). Among them, the total color difference (ΔE) of QC-G-BAC5 film was significantly correlated with the pH, acidity, and total colony count of pasteurized milk (R = 0.846, -0.930, -0.908, respectively). This new concept in smart packaging offers a straightforward and user-friendly freshness indicator.

Preparation and characterization of poly (vinyl alcohol) (PVA)/basmati rice starch (BRS) blend films cross-linked with aliphatic and aromatic carboxylic acids for food preservation and packaging

Preparation and characterization of poly (vinyl alcohol) (PVA)/basmati rice starch (BRS) blend films cross-linked with aliphatic and aromatic carboxylic acids for food preservation and packaging

Selenium loaded sodium alginate/polyvinyl alcohol nanocomposite film as wound dressing: structural, optical, mechanical, antimicrobial properties and biocompatibility

In the current research, synthesized Se-NPs were loaded into sodium alginate/polyvinyl alcohol SA/PVA blend, 1:2 (w:w), with different proportions to form nanocomposite films by using the solution casting method. The main goal is to enhance the physical and antibacterial properties of the polymer blend; therefore, it can be utilized for wound dressing applications. The physical aspects of the prepared films were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), atomic force microscope (AFM), scanning electron microscope (SEM), Energy dispersive X-ray (EDX), UV–Vis spectroscopic technique, and mechanical analysis to show the effect of increasing the concentration of Se-NPs from zero to 0.5 wt% on their properties. Regarding the XRD analysis, the calculated values of lattice strain (ε\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\varepsilon$$\\end{document}) increased from 0.005 to 0.013. The FTIR absorption spectrum recorded an intensity reduction and position shift in the main characteristic peaks of SA/PVA. The morphology of Se-NPs revealed a spherical shape with a mean diameter of 131.76 nm, as revealed by transmission electron microscopy (TEM). The surface morphological images showed the appearance of a few cracks; besides, the average roughness increased from 1.59 to 2.08 nm. According to the UV–Vis spectroscopic analysis, the optical band gap reduces (from 5.425 to 5.216 eV) for the direct transition and from (5.07–4.78 eV) for the indirect transition, which is an indication of the interaction between Se-NPs and SA/PVA blend. Young’s modulus, tensile strength, and yield strength of the films increased with the addition of selenium nanoparticles. On the other hand, the amount of selenium release significantly increased with enhancing the concentration of Se-NPs in SA/PVA blend film from 0.1 to 0.5 wt%. Additionally, the inclusion of Se-NPs supplied the polymer blend with excellent antimicrobial activity, which would remove the possibility of microbial infection at the wound site. Moreover, the prepared SA/PVA/Se nanocomposite films have good biocompatibility with Human Skin Fibroblast (HSF). The results suggest the potential of this nanocomposite to be used in wound dressing applications.

Insulator Polymer Matrix Construction on All-Small-Molecule Photoactive Blend Towards Extrapolated 15000 Hour T80 Stable Devices.

To boost the stability of all-small-molecule (ASM) organic photovoltaic (OPV) blends, an insulator polymer called styrene-ethylene-butylene-styrene (SEBS) as morphology stabilizer is applied into the host system of small molecules BM-ClEH:BO-4Cl. Minor addition of SEBS (1mg/ml in host solution) provides a significantly enhanced T80 value of 15000 hours (extrapolated), surpassing doping-free (0mg/ml) and heavy doping (10mg/ml) counterparts (900 hours, 30 hours). The material reproducibility and cost-effectiveness of the active layer will not be affected by this industrially available polymer, where the power conversion efficiency (PCE) can be well maintained at 15.02%, which is still a decent value for non-halogen solvent-treated ASM OPV. Morphological and photophysical characterizations clearly demonstrate SEBS's pivotal effect on suppressing the degradation of donor molecules and blend film's crystallization/aggregation reorganization, which protects the exciton dynamics effectively. This work pays meaningful attention to the ASM system stability, performs a smart strategy to suppress the film morphology degradation, and releases a comprehensive understanding of the mechanism of device performance reduction.

Chlorination of benzyl group on the terminal unit of A2-A1-D-A1-A2 type nonfullerene acceptor for high-voltage organic solar cells

Benzotriazole (BTA)-based A2-A1-D-A1-A2 type wide-bandgap (WBG) non-fullerene acceptors (NFAs) have shown promising potential in indoor photovoltaic, and in-depth investigation of their structure-property relationship is of great significance. Herein, we explored the chlorination effect of the side chain on the terminals. We introduced Cl atoms into the benzyl side chains in parent BTA5 to synthesize two NFAs, BTA5-Cl with mono-chlorinated benzyl groups and BTA5-2Cl containing bi-chlorinated benzyl groups. We chose D18-Cl with deep-energy levels and strong crystallinity to pair with these three acceptors, affording high photovoltage and photocurrent. With the stepwise chlorination, the open-circuit voltage (VOC) values decrease from 1.28, 1.22, to 1.20 V, while the corresponding power conversion efficiencies (PCEs) improve from 5.07 %, 9.15 %, to 10.96 %. Compared with BTA5-based OSCs, introducing Cl atoms downshifts the energy levels and slightly increases the non-radiative energy loss (0.14 < 0.17 < 0.19 eV), resulting in a sequential decrease in VOC. However, more chlorine atom replacements produce more effective exciton dissociation, higher charge transfer, and balanced carrier mobility in the blend films, ultimately achieving better PCEs. This work indicates that chlorination of the benzyl group on the terminals can improve the device's performance, implying good application potential in indoor photovoltaics.

Bioderived Chitosan Blend Films with Banana and Potato Extract

Bioderived Chitosan Blend Films with Banana and Potato Extract

Oxhide gelatin-regulated aramid nanofiber/liquid metal films with sandwiched structure for electromagnetic interference shielding

Liquid metal (LM) based electromagnetic interference (EMI) shielding materials with high conductivity and continuous deformation capacity are important needs for meeting modern advanced electronic equipment. However, an independent free-standing film with LM is difficult to achieve due to its unique fluidity properties. Here, a simple alternating filtration film-forming method was utilized to orderly construct a sandwiched EMI shielding film with LM stabilized by bio-based oxhide gelatin (gel) as the intermediate conductive layer, and two films of aramid nanofibers/oxhide gel (ANF/gel) as the external insulating protective layers. This design not only prevents LM from being exposed to environmental conditions, but also reduces the risk of chemical corrosion in practical applications. Under optimal LM addition conditions, the sandwiched film (0.3-3 L) exhibited better EMI shielding performance of 50.4 dB in the X-band than the blended film (0.7 dB), as well as excellent mechanical properties (tensile strength of 65.8 MPa, strain 8.6 %). More importantly, the sandwiched film still maintained reliable EMI shielding performance after being experienced largely physical deformation. This study provides a new solution for preparing LM-based EMI shielding composites, and is expected to arouse pursuit of high EMI shielding effects of bio-based gel while also paying attention to their safety.

Alginate/hyaluronic acid/gelatin ternary blended films as pH-sensitive drug carriers: In vitro ampicillin release and kinetic studies

Researchers continuously focused on the fabrication of innovative drug delivery systems to prevent microbial infections while minimizing systemic side effects. Among these, pH-sensitive antibiotic release systems based on bio-based materials have gained great attention due to their ability to precisely modulate drug kinetics and enhance therapeutic efficacy. Herein, pH-sensitive alginate/hyaluronic acid/gelatin ternary blended films were fabricated for the controlled release of ampicillin. Swelling capacity, hydrolytic degradation profile, pH reversibility and in vitro ampicillin release behavior of produced films were investigated in both simulated gastric (pH 1.2) and intestinal (pH 7.4) environments. The cumulative release amount of ampicillin at pH 1.2 (61.0 ± 1.07 mg drug/g polymer) was greater than that of at pH 7.4 (43.0 ± 1.05 mg drug/g polymer) proved that release behavior of ampicillin for produced films is pH-dependent. Based on the fitted release data, best fit was found as the first-order kinetic model with the highest R2 values of 0.966 and 0.962 for both pH conditions. According to Korsmeyer-Peppas model, drug release mechanism is also controlled by case II-transport. Furthermore, produced films demonstrated excellent cytocompatibility. All results revealed that obtained films could be a promising drug carrier to traditional targeting systems for site-specific, pH-sensitive ampicillin delivery in both gastric and intestine.

Manipulating epoxy-polycarbonate sandwich films with enhanced dielectric performance via solution-immersion process

Epoxy-polycarbonate sandwiched films with enhanced dielectric performance were prepared in this study. Unlike traditional tedious multiple scratch-coating approach, the sandwich dielectric films were prepared based on a convenient solution-immersion process. Polycarbonate solutions with different concentration were applied to adjust the film composition and compared with epoxy-polycarbonate blending film. We found that rather than deteriorating the breakdown strength as shown in the blending counterpart, sandwiched films prepared by solution immersion shows superior breakdown strength (709.6 MV/m), almost 40 % better than both epoxy and polycarbonate components. Moreover, tan δ of the films prepared from solution-immersion (<0.005) is apparently smaller than blending samples (∼0.008). Both factors lead to admirable ideal dielectric energy storage performance (8.44 J/cm3) of the film, better than many conventional polymers.

Some Polyaniline Blends Films Physical Characteristics

The casting technique has been successfully used to prepare films with polyaniline (PAni) blends. Films made from the (PMMA ,PAni ), PS, and POE at consistent concentrations have a thickness of 50 micro meters. By using XRD and FTIR spectroscopy, the PAni Blends films are identified. Using this method, the presence of the films' distinctive bonds was discovered. Electrical characteristics showed that, the conductivity of PAni blend sheets measured at room temperature is as follows: for PAni blends made with PMMA, PS, and PEO, respectively: (5.18, 9.23 and 0.12) 10-9 S.cm-1. The tensile stress and hardness numbers of the numerous PAni blend films can differ from one another depending on the mechanical characteristics. The results also indicated that the polymers can be used with a very thin layer in photovoltaic cell applications.

Heat-sealable, transparent, and degradable arabinogalactan/polyvinyl alcohol films with UV-shielding, antibacterial, and antioxidant properties

Petroleum-based packaging materials are nondegradable and unsustainable and thus are harmful to the environment. Renewable packaging films prepared from bio-based raw materials are promising alternatives to petroleum-based packaging materials. In this study, colorless and transparent bio-based films were successfully cast using a solution containing a mixture of arabinogalactan (AG) and poly (vinyl alcohol) (PVA). Vanillin was incorporated into the mixture to endow the films with UV-shielding, antioxidant, and antibacterial properties. The morphological, physical, antioxidant, and antibacterial properties of the blend films were then characterized. At an AG:PVA weight ratio of 1:3, and the vanillin content was 0.15 %, the tensile strength of the AG/PVA/Vanillin (APV) films reached ~28 MPa, while their elongation at break reached ~475 %. The addition of vanillin significantly affected the antioxidant and antibacterial properties of the blend films, which exhibited superb UV barrier capacity. The APV films exhibited extremely low oxygen transmittance, delaying the onset of mold/rot in strawberries and reducing their weight loss. Because of the heat sealability of the blend films, they can be used for encapsulating various substances, such as concentrated laundry liquid. Moreover, the blend films were recyclable and biodegradable. Thus, these films have great potential for applications that require sustainable packaging.