Acetate Films Research Articles

A Programmable Actuator as Synthetic Earthworm.

Natural earthworm with the ability to loosen soils that favors sustainable agriculture has inspired worldwide interest in the design of intelligent actuators. Given the inability to carry heavy loads and uncontrolled deformation, the vast majority of actuators can only perform simple tasks by bending, contraction, or elongation. Herein, a degradable actuator with the ability to deform in desired ways is presented, which successfully mimics the burrowing activities of earthworms to loosen soils with increased soil porosity by digging, grabbing, and lifting the soil when it receives rains. Such a scarifying actuator is made of degradable cellulose acetate and uncrosslinked polyacrylamide via the swelling-photopolymerizing method. The water absorption of polyacrylamide in moisture conditions causes rapid and remarkable bending. Such mechanical bending can be controlled in specific areas of the cellulose acetate film if polyacrylamide is polymerized in a patterned way, so as to generate complicated deformations of the whole cellulose acetate. Patterning polyacrylamide within cellulose acetate is achieved based on reversible surface protection by means of pen writing, rather than the traditional masking techniques. The water-induced deformation of programmable cellulose-based actuators is well preserved in soil, which is appropriate for promoting rain diffusion as well as root breath.

Investigation of the influence of plasticizers on the biodegradability of cellulose acetate

AbstractIn order to evaluate the biodegradability of the cellulose acetate (CA) films plasticized with different concentrations of glycerol (GLY) or triethyl citrate (TEC), analysis of scanning electron microscopy (SEM), Fourier transfer infrared spectroscopy (FTIR), and thermogravimetric analyses (TGA) were conducted through 180 days. Throughout the analysis, indicators of plasticizer exudation were observed, including changes in visual appearance and mass loss, ranging from 39.141% and 20.663% (first day) up to 0.524% and 0.488% (last day) for TEC and GLY plasticizer based films, respectively. Changes were also noted in the infrared spectrum, and TGA plots with polymer degradation peaks from 332.09 to 400.96 cm−1 for both plasticizers based films (TEC and GLY, respectively), regardless of the day of analysis. All assays revealed plasticizer losses, but there was no evidence of films' biodegradation during the experimental time. In perspective, this systematic approach can be extended to study other polymers and other biodegradation conditions.

Fabrication and characterization of cellulose acetate film containing Falcaria vulgaris extract

Fabrication and characterization of cellulose acetate film containing Falcaria vulgaris extract

Effects of the Solvent Vapor Exposure on the Optical Properties and Photocatalytic Behavior of Cellulose Acetate/Perylene Free-Standing Films.

The search to deliver added value to industrialized biobased materials, such as cellulose derivatives, is a relevant aspect in the scientific, technological and innovation fields at present. To address these aspects, films of cellulose acetate (CA) and a perylene derivative (Pr) were fabricated using a solution-casting method with two different compositions. Consequently, these samples were exposed to dimethylformamide (DMF) solvent vapors so that its influence on the optical, wettability, and topographical properties of the films could be examined. The results demonstrated that solvent vapor could induce the apparent total or partial preferential orientation/migration of Pr toward the polymer-air interface. In addition, photocatalytic activities of the non-exposed and DMF vapor-exposed films against the degradation of methylene blue (MB) in an aqueous medium using light-emitting diode visible light irradiation were comparatively investigated. Apparently, the observed improvement in the performance of these materials in the MB photodegradation process is closely linked to the treatment with solvent vapor. Results from this study have allowed us to propose the fabrication and use of the improved photoactivity "all-organic" materials for potential applications in dye photodegradation in aqueous media.

Triggering Degradation of Cellulose Acetate by Embedded Enzymes: Accelerated Enzymatic Degradation and Biodegradation under Simulated Composting Conditions.

A green strategy that significantly accelerates the biodegradation rate of cellulose acetate (CA) by triggering deacetylation was demonstrated. Lipase isolated from Candida rugosa was immobilized on CA particles (immobilized lipase (IL)) by a physical entrapment method and further incorporated in CA films. After 40 days of aging in contact with external enzymes (lipase and cellulase), the number-average molecular weight (Mn) of CA/IL 5% decreased by 88%, while the Mn of CA only exhibited a 48% reduction. Fourier transform infrared and nuclear magnetic resonance spectroscopy of CA/IL 5% indicated significant deacetylation, which was further supported by the decrease of the water contact angle from 59 to 16°. These drastic changes were not observed for CA. Similar differences in the degradation rate were observed during aging under simulated composting conditions. After 180 days of simulated composting, traces of CA/IL 5% were barely observable, while large pieces of CA still remained. This could open the door to modified lignocellulose materials with retained biodegradability, also reducing the requirements for the degradation environment as the process is initiated from inside of the material.

Stabilized cellulose separator based on NaCl and glycerol with uniform structure

A membranes used as battery separators must be thermally stable because they have to withstand extreme environments such as high temperatures. However, the membrane also must have a uniformly porous structure for the movement of Li ion, which reduces the thermal stability of the membrane. Thus, to solve this problem, thermally stable membrane was developed. Here in, for the first time, we succeeded that nano-sized porous composite membrane with thermally stable was fabricated from high molecular weight cellulose acetate (CA) and additives, Glycerol and NaCl, using a hydraulic force. The mol ratio of CA and glycerol was fixed at 1 and 0.1, respectively. With various mol ratio of NaCl, The optimal ratio for the additives to be well dispersed in the composite was investigated through water flux. At 0.07 mol ratio NaCl, it was measured that average water flux was 9.431 L/m2h and the coefficient of determination (R2) was 0.9802, which meaning it has a reproducible and largest water flux than other NaCl mol ratios. Thus, the optimal ratio was glycerol:NaCl = 0.1:0.07 mol ratio. In the optimal ratio, average porosity of the composite was measured to 10.20 ± 0.08%. It was confirmed by SEM that the pore sizes of the surfaces were similar. The thermodynamic properties of the CA/glycerol/NaCl composites was measured using TGA and DTG. It was shown that the thermal stability of the CA/glycerol/NaCl composite had a thermal behavior similar to neat CA film even though pore was formed. This was demonstrated that thermal stability was improved by stabling coordination bonding between the carbonyl group of CA and remaining additives. In addition, the degree of coordination bonding with the carbonyl group of CA according to the amount of NaCl was investigated using XPS.

Zero-valent metal incorporated cellulose acetate oxygen scavenging system for packaging of liquid food

Preserving packaged food from oxidative degradation is essential to improve the food quality and shelf life. This work focuses on synthesizing inexpensive zero-valent metal-incorporated polymeric films with a high oxygen scavenging rate, thus decreasing dissolved oxygen and bacterial growth. The optimal solvent for film synthesis was determined, with CADMSO films demonstrating the highest scavenging rate of 0.028 day−1. Next, zero-valent Fe, Cu, and Al nanoparticles were synthesized and incorporated into cellulose acetate films for use in active packaging. The resulting ZFe films showed the highest scavenging rate of 0.994 day−1 followed by ZCu and ZAl films with rates of 0.604 day−1, and 0.3516 day−1, respectively. Both ZFe and ZCu films exhibited potent antibacterial effects against gram-positive and gram-negative bacteria after 24 h, with reductions exceeding 99%. ZAl films showed a 99% reduction in bacterial colonies for gram-positive and a 97.5% reduction for gram-negative after 24 h. When tested with fruit juice, ZFe films exhibited the greatest scavenging capacity, achieving a 100% reduction in dissolved oxygen within 5 days. The films exhibited stability, as observed from FTIR and TGA analysis. The films' potent oxygen scavenging and bactericidal properties suggest that they may have applications as packaging agents.

Rapid transesterification of cellulose in a novel DBU-derived ionic liquid: Efficient synthesis of highly substituted cellulose acetate

Cellulose acetate (CA) is one of the most important cellulose plastics that has demonstrated extensive applications in many areas. In search of a more sustainable and efficient way to prepare CA, we synthesized a novel ionic liquid, [DBUC8]Cl, based on the commonly used catalyst DBU (1,8-diazabicyclo[5.4.0]undecyquin-7-ene) in a simple manner. [DBUC8]Cl can dissolve cellulose more efficiently than the same type of imidazolyl ionic liquid, owing to the stronger alkalinity of DBU. It is noteworthy that highly substituted CA (DS = 2.82) was successfully synthesized via transesterification with alkenyl ester under mild conditions (80 °C, 40 min) without the addition of a catalyst in this solvent, which is superior to most of the reported work. Furthermore, we confirmed that the synthesized CA had good thermoplasticity, and a transparent cellulose acetate film (CAF) was obtained by hot pressing with a small amount of glycerol. Therefore, we propose a new DBU-derived ionic liquid, which may serve as a versatile platform system for producing cellulose-derived bioplastics more sustainably and efficiently.

DBD plasma coupling MnO2-Fe3O4-cellulose acetate films for sulfamethoxazole degradation: Insight for catalytic ozonation and Fenton effect

In this study, efficient degradation of sulfamethoxazole (SMX) by coupling dielectric barrier discharge (DBD) plasma and MnO2-Fe3O4-cellulose acetate (MnO2-Fe3O4-CA) film catalyst was investigated. SEM, XRD, FT-IR and XPS were carried out to confirm the successful preparation of the MnO2-Fe3O4-CA film. The optimal constitution of MnO2-Fe3O4 and CA was evaluated according to the SMX degradation under different conditions of the prepared films. When 3 % 3:1 MnO2-Fe3O4-CA films were added into the DBD system, the removal rate of SMX could reach 93.55 %. Experiments on the effect of the initial pH value of the solution indicated that the SMX degradation was better under both neutral and alkaline solution conditions. Mechanism analysis show that ·OH, ·O2− and 1O2 were involved in the degradation of SMX. The MnO2-Fe3O4-CA catalyst could burst Fenton reaction and promote ozone decomposition, and accordingly generated more reactive oxygen species (ROS) responsible for the increase of the SMX degradation. The cyclic experiments showed that film had good repeatability and stability. Four routes of SMX degradation were given according to the byproducts analysis, and the toxicity was evaluated.

Ammonia-sensitive cellulose acetate-based films incorporated with Co-BIT microcrystals for smart packaging application

Nowadays, there is an increasing demand for smart packaging materials capable of effectively monitoring the food freshness. In this study, new Co-based MOF (Co-BIT) microcrystals with ammonia-sensitivity and antibacterial function were constructed and then loaded within cellulose acetate (CA) matrix to create smart active packaging materials. The influences of Co-BIT loading upon structure, physical, and functional properties of the CA films were then thoroughly explored. It was observed that microcrystalline Co-BIT was uniformly integrated inside CA matrix, which caused significant promotions in mechanical strength (from 24.12 to 39.76 MPa), water barrier (from 9.32 × 10−6 to 2.73 × 10−6 g/m·h·Pa) and ultraviolet light protection performances of CA film. Additionally, the created CA/Co-BIT films displayed striking antibacterial efficacy (>95.0 % for both Escherichia coli and Staphylococcus aureus), favorable ammonia-sensitivity function as well as color stability. Finally, the CA/Co-BIT films were successfully applied for indicating the spoilage of shrimp through discernible color changes. These findings suggest that Co-BIT loaded CA composite films have great potential for use as smart active packaging.

Highly dense and porous structure generated by 1,2,3-trihydroxy propane in cellulose materials

In this study, for the first time, we succeeded in manufacturing a high molecular weight cellulose acetate (CA) for based battery separator, capable of controlling pores and improved thermal stability and mechanical strength without a support. The CA/1,2,3-trihydroxy-propane composite as film-type was prepared by a free-standing method using doctor blade. The composite was applied to hydraulic pressure from 2 to 8 bar. Due to 1,2,3-trihydroxy-propane, the plasticized area of the composite was pierced by high water-pressure to form channels. It was proved that the number and size of pores can be controlled by adjusting the water pressure. The pore size became varied from nano to micro-size and the average pore size was 224 nm with 84.6% of the porosity. While measuring the thermal decomposition temperature of the composite by TGA, it was observed that the composite with water pressure at 8 bar began to be thermally decomposed at about the same temperature as the neat CA film but decomposed more slowly. In addition, it was confirmed that the intermolecular interaction force between CA chains increased through FT-IR spectroscopy. Therefore, it can be deduced that the thermostability and mechanical strength were improved despite the formation of pores by applying water-pressure.

Preparation of polyaniline‐poly(ethylene‐vinyl acetate) film: Resistivity in the ESD range

AbstractFilms of polyaniline (PANI) salt with poly (ethylene‐vinyl acetate) (EVA) with two different PANI salts, PANI‐methane sulfonic acid (PANI‐MSA) and PANI‐p‐toluene sulfonic acid (PANI‐PTSA) are prepared by solution processing technique for electrostatic discharge (ESD) application. PANI‐MSA/PANI‐PTSA salts were synthesized by emulsion polymerization pathway then dispersed the PANI salt in xylene solvent. EVA was dissolved in xylene solvent. Series of PANI salt/EVA films were prepared by mixing a particular amount of PANI dispersion to a fixed amount of EVA solution and evaporated the solvent. PANI‐EVA films were evaluated by tensile strength, elongation at break and surface resistivity measurements. The results of PANI‐MSA/EVA films are compared with the results of PANI‐PTSA/EVA films. Also, PANI‐MSA/EVA and PANI‐PTSA/EVA solutions are coated on different substrates and measured their electrical resistivity for ESD application. Morphological study and thermal behaviors of PANI‐MSA/EVA films are carried through FE‐SEM and TGA respectively. Sphere morphology of EVA changed to swollen sheet like morphology with the addition of PANI, and the spaces between the sheets increased with the increase in PANI content. The surface resistivity of the EVA‐PANI films are found to be in the range of 104–108 Ω sq−1, which is suitable for ESD application.

Fabrication and Characterization of EVA Resins as Adhesives in Plywood.

The practical problem of free formaldehyde pollution in the plywood industry is that polyethylene films have been shown to be able to replace some urea-formaldehyde resins for wood adhesives. To broaden the variety of thermoplastic plywood, reduce the hot-press temperature, and save energy consumption, an ethylene-vinyl acetate (EVA) film was selected as a wood adhesive to manufacture a novel wood-plastic composite plywood via hot-press and secondary press processes. The effects of the hot-press and secondary press processes at different levels on the physical-mechanical properties of EVA plywood (tensile shear strength, 24 h water absorption, and immersion peel performance) were evaluated. The results showed that the properties of the resulting plywood using the EVA film as an adhesive could meet the type III plywood standard. The optimum hot-press time was 1 min/mm, the hot-press temperature was 110-120 °C, the hot-press pressure was 1 MPa, the dosage film was 163 g/m2, the secondary press time was 5 min, the secondary press pressure was 0.5 MPa, and the secondary press temperature was 25 °C. EVA plywood can be used in indoor environments.

Graphene nanoplatelet/cellulose acetate film with enhanced antistatic, thermal dissipative and mechanical properties for packaging.

With the increased concern over environment protection, cellulose acetate (CA) has drawn great interests as an alternative for packaging material due to its biodegradability and abundant resources; whereas, the poor antistatic property and thermal conductivity restrict its application in packaging. In this work, we proposed a simple but effective strategy to produce high performance graphene nanoplatelet (GNP)/CA composite films via the consecutive homogenization and solvent casting processes. Relying on the spontaneous absorption of CA during homogenization, the GNP/CA produced shows an excellent dispersibility in the N,N-Dimethylformamide (DMF) solution and many fewer structural defects compared with GNPs alone. As a result, the composite films obtained exhibit simultaneously and significantly enhanced antistatic, heat dissipative and mechanical properties compared with CA. Specifically, the GNP/CA composite with the optimal formula has promising overall performances (namely, surface resistivity of 3.33 × 107Ω/sq, in-plane thermal conductivity of 5.359 , out-of-plane thermal conductivity of 0.785 , and tensile strength of 37.1MPa). Featured by its promising overall properties, simple production processes and biodegradability, the as-prepared GNP/CA composite film shows a great potential for application in packaging. The online version contains supplementary material available at 10.1007/s10570-023-05155-2.

Biomass-based carbon quantum dots for polycrystalline silicon solar cells with enhanced photovoltaic performance

Polycrystalline silicon solar cells modified using biomass resources are promising candidates to accomplish the goal of carbon neutrality. Developing a device with high power conversion efficiency (PCE) is important to resolve the ever-increasing energy shortage issues. Therefore, we develop a facile solution-casting approach to synthesise ethylene-vinyl acetate (EVA) films modified with ultra-high fluorescent carbon quantum dots (CQDs). The films were coated on the surface of polycrystalline silicon solar cells and the PCE increased from 13.19% to 13.65%. The ultra-high fluorescent CQDs were prepared from Ginkgo biloba via a hydrothermal process, and different parts of Ginkgo biloba-based CQDs were investigated in various conditions. The ultra-high fluorescent CQDs obtained at 180 °C, 8 h and a reaction concentration of 0.048 g/mL from Ginkgo wood resulted in high fluorescence of up to 976.74 a.u.. At an excitation wavelength of 365 nm. This work substantially expands the potential of EVA films containing ultra-high fluorescent CQDs for applications in the photovoltaic, environment and energy fields.

Effect of down-shifting phosphor particles on crystalline silicon solar cells

Introducing down-shifting phosphor particles onto solar cells can improve their spectral response to short wavelength photons, but it also leads to the rise of reflection in middle and long wavelength range due to the scattering by phosphor particles. In this work, the down-shifting solar cells are fabricated by packaging crystalline silicon solar cells with ethylene vinyl acetate (EVA) films which include different concentration of down-shifting Ce-doped yttrium aluminum garnet (YAG:Ce) phosphor particles. Experimental result shows that the increasing concentration of YAG:Ce phosphors strengthens the down-shifting effect and makes the reflection rise. The competition between the down-shifting effect and the reflection results in the best improvement of the solar cells when the phosphor's concentration is 0.7%. The optical ray-tracing simulations clarify that the packaged solar cell with YAG:Ce absorbs less photons than those without YAG:Ce, but their conversion efficiency is higher than those without YAG:Ce. This indicates that the penetration depth of the short wavelength photons is responsible for the poorer spectral response of the solar cells in the short wavelength range.

Improved performance of metal-organic frameworks loaded cellulose acetate based film for packaging application

Bio-nanocomposite-based packaging materials have gained significance due to their possible applications in food packaging. Cellulose acetate is a biopolymer obtained by acetylation of cellulose and has characteristics such as biocompatibility, biodegradability and high transparency. Introducing iron-based metal-organic frameworks offer good mechanical strength, unique surface area and both chemical and thermally stability, making them favourable as supporting materials in fabricating polymer-based packaging materials. Among them, Fe- (Material Institute Lavoisier) MIL-88A is an iron-based nontoxic metal-organic framework, integrated with cellulose acetate and spinach extract was added to the prepared material in different compositions and cast as film. The Spinach loaded, Fe- (Material Institute Lavoisier) MIL-88A integrated cellulose acetate film significantly enhanced the tensile strength, water vapour permeability, and anti-microbial activity. The prepared film is then characterized using a scanning electron microscope (SEM), Fourier transforms infrared spectrometer (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Further, studies on mechanical properties as well as degradation tests and real-time applications of the prepared films were carried out.

Wound dressing candidate materials based on casted films of cellulose acetate modified with zirconium oxide (ZrO2), and gallium oxide (Ga2O3)

Wound dressing candidate materials based on casted films of cellulose acetate modified with zirconium oxide (ZrO2), and gallium oxide (Ga2O3)

Plasma-Polymerized and Iodine-Doped Polyvinyl Acetate for Volatile Organic Compound Gas Sensing Applications

Nowadays, the increased emission of hazardous volatile organic compounds (VOCs) due to rapid growth in the manufacturing industry has enforced demand for highly sensitive, selective, and stable gas sensors. Among the different types of gas sensors, we resolved issues associated with chemoresistive alcohol sensors like low selectivity, temperature instability, and long-term instability using iodine-doped polyvinyl acetate (IPVAc) films. These polymer-based chemoresistive sensors will be beneficial for low power consumption, ease of manufacture, and long-term stability owing to their simple structure and operation. The polymer films were prepared using the inductively coupled tubular plasma polymerization method. These films were doped with iodine at room temperature. The physicochemical characterization of prepared films confirmed the uniform coating of granular type morphology, iodine doping, and cubical crystal structure. The obtained maximum sensitivity was 122 and 7360 a.u. for 1000 ppm of methanol gas for polyvinyl acetate (PVAc) and IPVAc films, respectively. Also, IPVAc films demonstrated sensitivities of 5554 and 1995 a.u. for 1000 ppm of each ethanol and 2-propanol gas, respectively. IPVAc films illustrated the highest selectivity of 600 a.u. for alcohols over other VOCs like acetone, benzene, toluene, and dichloromethane. The high electronegativity of IPVAc films due to iodine doping is the key origin of the highly selective adsorption of VOCs. Additionally, the IPVAc films have stable sensitivity performance over the temperature range of 30–130 °C and repeatability over 60 days. Thus, the plasma-polymerized IPVAc films can be applied for fabricating highly selective, sensitive, and stable VOC sensing applications.

Preparation of cellulose acetate film with dual hydrophobic-hydrophilic properties using solution blow spinning

Solution blow spinning (SBS), a processing method alternative to electrospinning, where pressured air is used instead of an electric field, was used in this work for the preparation of cellulose acetate (CA) materials. The sequential use of SBS to produce a double-layered film is also investigated. Mixtures of acetone with acetic acid or N,N-dimethylformamide (DMF) were studied as systems for polymer solution preparation. The type of produced material (flat film or multi-structured membranes constituted from submicrometric fibers with beads), its thermal properties, crystallinity, and morphology are more dependent on the solvent system than other SBS processing parameters. Roughness and porosity of differently produced materials influence wettability measured by the contact angle, which ranges in this work from approx. 69.8° ± 3° for a flat film to 104° ± 5° for fibrous material. Finally, a double-layered film, prepared by sequential SBS of individual layers different in terms of wettability, renders a standalone film of dual wettability, with one side hydrophobic and the other hydrophilic.