Acetate Films Research Articles

Efficient synthesis of cellulose acetate through one-step homogeneous acetylation of cotton cellulose in binary ionic liquids

Cellulose acetate (CA) is an important cellulose derivative with a wide range of applications. To adopt a more efficient and environmentally friendly method to synthesize cellulose acetate, a binary ionic liquid mixture of 1-butyl-3-methylimidazole chloride salt (BmimCl) and 1-butyl-3-methyldihydroimidazole phosphate (BmimH2PO4) was used. Compared to the conventional methods, this approach didn't require pre-activation of cellulose and the process of homogeneous acetylation proceeded without a catalyst. By simply adjusting the reaction conditions, cellulose acetate with a degree of substitution (DS) in the range of 0.83–3.0 was produced by one-step homogeneous acetylation without hydrolysis. Furthermore, the cellulose acetate film produced by solvent casting exhibited smooth surface characteristics, 95 % transparency, and 57.9 MPa tensile strength. Therefore, this study highlights the importance of using binary ionic liquid mixtures for facile synthesis of cellulose acetate. Due to their excellent transparency and mechanical properties, newly synthesized cellulose acetate films could replace commercial films.

Effect of Polar Aprotic Solvents on the Physical, Chemical, and Mechanical Properties of Cellulose Acetate Bioplastic Films

Abstract There has been a growing interest in bioplastics as a solution to increasing greenhouse gases and the pile up of waste caused by fossil-based non-biodegradable plastics. However, the use of harmful solvents in their synthesis may continue to be detrimental to the environment. A novel bio-based solvent, CyreneTM, is seen as an alternative to toxic polar aprotic solvents. With this, the study aimed to compare the properties of cellulose acetate (CA) bioplastic films using acetone, dimethylformamide (DMF), and CyreneTM as solvents and glycerol as the plasticizer. The following tests were used to characterize the synthesized bioplastics: Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), density, moisture content, biodegradability, tensile strength, Young’s Modulus, and elongation at break. CyreneTM films were found to have significantly high moisture content and elongation at break. A weight loss of 29% in biodegradation was recorded for CyreneTM films without glycerol over the course of 23 days. The properties of the CyreneTM films show that it may be applicable for mulching films and seedling containers in agricultural applications due to their high affinity for water. It can be concluded that the study of CyreneTM solvent for the synthesis of CA films and its properties contributes to greener synthesis methods for bioplastics.

A scalable and aging-resistant film for radiative cooling

Passive radiative cooling could reduce energy consumption by reflecting sunlight and radiating heat into outer space at long wave infrared. However, it is challenging that development of environmentally stable radiation-cooled materials that are easy to manufacture and have good weathering resistance. In this work, we developed a scalable radiative-cooling porous film of doped BaSO4 cellulose acetate(BSCA) with good environmental stability. The reflectivity was 0.94 with BSCA film to scatter most of the sun’s rays efficiently and an emissivity of 0.98 to radiate heat rapidly. The maximum temperature different with BSCA film were reduced by 8 ℃ less than the porous cellulose acetate (PCA) film, 13 ℃ than the commercial white paint (CWP) film. Meanwhile, in the switch boxes testing, the surface maximum temperature of the switch box coated with BSCA film were reduced by 9.9 ℃ than the switch box coated with CWP film, which were reduced by 14.7 ℃ than the original switch box. The simulated cooling power of BSCA film was 140.23 W·m−2. The BSCA film shows good optical performance and cooling performance after 3 months of outdoor aging test. The BSCA film is aging-resistant, easy to prepare and convenient for scalable production.

Durable photobioreactor antibiofouling coatings for microalgae cultivation by photoreactive poly(2,2,2-trifluoroethyl methacrylate)

To improve the durability of the photobioreactor antibiofouling surface for microalgal cultivation, a series of photoreactive poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) were successfully synthesized and used to modify ethylene-vinyl acetate (EVA) films by a surface coating and UV light grafting method. Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy analysis (XPS) and fluorescence microscopy results indicated that PTFEMA were fixed successfully onto the EVA film surface through a covalent bond. During the microalgal adhesion assay, the number of EVA-PTFEMA film-adhered microalgae was 41.4% lower than that of the EVA film. Moreover, the number of microalgae attached to the EVA-PTFEMA film decreased by 61.7% after cleaning, while that of EVA film decreased by only 49.1%. It was found that the contact angle of EVA-PTFEMA film surface increased, and remained stable when immersed in acid and alkali solution for up to 90 days. HIGHLIGHTS Durable photobioreactor antibiofouling surfaces for microalgal cultivation were prepared successfully. The contact angle of antibiofouling coating surface remained stable in acid and base environment for 90 days. The attached microalgae on antibiofouling surface decreased 41.4% than those of unmodified surface. The attached microalgae on antibiofouling surface could be cleaned by 61.7% through changing the flow velocity of microalgal suspension.

Effect of the molar mass of chitosan and film casting solvents on the properties of chitosan films loaded with Mentha spicata essential oil for potential application as wound dressing

Chitosan based films endowed with antibacterial features have witnessed remarkable progress as potential wound dressings. The current study aimed at appraising the effects of the molar mass of chitosan (MM) and the film casting acids on the properties of unplasticized chitosan films and plasticized MSO-embedded chitosan films in order to provide best suited film formulation as a potential candidate for wound dressing application. The prepared films were functionally characterized in terms of their qualitative assessment, thickness, density, swelling behavior, water vapor barrier, mechanical and antibacterial properties. Overall, all chitosan films displayed thickness lower than the human dermis even though thicker and denser films were produced with lactic acid. Assessment of the swelling behavior revealed that only high molar mass (HMM) chitosan films may be regarded as absorbent dressings. Moreover, unplasticized HMM lactate (HMM-LA) films furnished lower stiffness and higher percent strain break as compared to acetate films, due to the plasticizing effect of the remaining lactic acid as alluded by the FTIR analysis. Meanwhile, they provided suitable level of moisture and indicated substantial antibacterial activity against S. aureus and E. coli, the most commonly opportunistic bacteria found in infected skin wound. Plasticized chitosan films doped with MSO were significantly thicker and more permeable to water compared to unplasticized films. Furthermore, MSO significantly potentiate the antibacterial effect of chitosan-based films. Therefore, plasticized HMM-LA/MSO chitosan film flashing good swelling behavior, adequate WVTR and WVP, suitable mechanical properties and antibacterial performances substantiated to be a promising antibacterial dressing material for moderately exuding wounds.

Enhancing thermal consistency and stability of quantum dots through encapsulation: A study on microscale-structured hybrid for WLEDs

Quantum dots (QDs) are regarded as highly potential materials for color conversion in light-emitting diodes (LEDs) and display technologies owing to their distinctive and outstanding optical characteristics. Nevertheless, the energy transfer process occurring among various colored QDs, known as Förster resonance energy transfer (FRET), results in a notable redshift in fluorescence emission, restricting the precise control of photoluminescence spectra in fabricated devices. This study presents a dual-impact technique to enhance the stability of CdSe/ZnS colloidal QDs while also preventing the FRET process. This is achieved by encapsulating the QDs within silica (SiO2) and ethylene-vinyl acetate (EVA) films. The research features two distinct encapsulation methods: enveloping multiple QDs within a SiO2 matrix (MQD) and adsorbing QDs onto SiO2 spheres as a shell (SQD and SQDS). Those hybrid structures are successfully fabricated with their nanostructure, chemical composition, and optical properties extensively analyzed. Moreover, the photo-physical properties of QDs/SiO2/EVA hybrid composite films and their impact on blue lightemitting diodes (LEDs) and White-LEDs have been conducted. Among those formulations explored, the MQD/EVA films stand out, displaying natural sunlight color emission with a color temperature of 4214 K, a color coordinate at (0.37, 0.37), and significant improvements in chromatic and thermal stability under high driving power. The successful integration of high-molecular-weight polymers and SiO2 coatings highlights the effectiveness of this approach in producing robust, high-quality QD-polymer film composites, making them ideal candidates for display technologies.

A comparative study of mechanical crushing and pyrolysis techniques for separation and recovery of discarded polycrystalline silicon photovoltaic modules

With the rapid growth of the photovoltaic (PV) industry, efficient recovery and utilization of discarded polycrystalline silicon PV modules have attracted increasing attention. This study compares the application of mechanical crushing and pyrolysis techniques in the recovery of PV modules. The results indicate that while mechanical crushing can preliminarily disintegrate materials, its effectiveness in separating valuable materials such as silver and aluminum is limited, particularly for particles larger than 1 mm. In contrast, pyrolysis techniques demonstrate outstanding performance in removing organic matter and separating silicon wafers and glass, notably enhancing the recovery rate of large glass particles. However, the brittleness of silicon wafers presents a challenge during pyrolysis. Furthermore, the pyrolysis mechanisms of ethylene-vinyl acetate (EVA) film and backsheet materials are thoroughly discussed. The pyrolysis process of EVA film involves two stages: firstly, the preferential decomposition of acetyl oxygens on ester side chains, followed by further pyrolysis decomposition of the main chain and side chains to generate alkanes. Pyrolysis of polyethylene terephthalate (PET) begins with the generation of methyl and benzoyl radicals, while polyvinyl fluoride (PVF) and polyvinylidene fluoride (PVDF) pyrolysis initiates with the detachment of head-group units, followed by sequential detachment of chain units. Given the advantages of pyrolysis techniques, this study recommends them as the preferred method for PV module recovery.

Features of the formation of cohesive and adhesive strengths by non-structured and structured polyvinyl acetate films during wood gluing

The formation of a higher number of hydrogen bonds in the structured polyvinyl acetate film compared to the unstructured one was established by means of infrared spectroscopy method. It was concluded that the structured polyvinyl acetate film has a higher cohesive strength than unstructured. It was revealed that the films subjected to moisture loads (with the amount of sorbed moisture lower than the swelling limit of the adhesive film) would show greater cohesive strength compared to the films which were not subjected to moisture loads due to the formation of a higher number of hydrogen bonds. Based on the obtained results, it was predicted that the system "structured film after moisture loads/wood substrate" would exhibit the highest adhesive strength, explained by an increase in the number of hydrogen bonds between the film components and the wood cellulose. It was theoretically predicted that in order to provide high cohesive and adhesive strengths of polyvinyl acetate adhesive joints of wood ensuring, moisture saturation should be lower than the saturation limit of the wood fiber and the adhesive film simultaneously.

Enhancing cellulose acetate film with green plasticizers for improved performance, biodegradability, and migration study into a food simulant

Cellulose acetate (CA) is a synthetic compound obtained by acetylation of cellulose. It is widely used for various applications, including food packaging films. However, CA is very rigid due to the β-d-glycose ring in its main chain, and the presence of many hydrogen bonds between the hydroxyl groups, which limits the extent of its application. Therefore, plasticizers are generally used to provide flexibility particularly when used for packaging. The migration of plasticizers from packaging materials to packaged food can pose a risk to human health, particularly when the plasticizers present some levels of toxicity. The objective of this research is to compare the effect of widely used plasticizers glycerol, tris (2-ethylhexyl) phosphate (TEHP) and rosemary essential oil on the properties of cellulose acetate films for food packaging. Cellulose acetate films were prepared via solvent casting method followed by plasticizing. The films prepared were characterized using infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-Ray diffraction analysis (XRD) and others analysis. The results show that rosemary essential oil has the lowest migration rate to food simulants. Rosemary can play dual roles, a plasticizer by improving mechanical properties and an active agent (antioxidant, antimicrobial, and UV protector, and promotor of biodegradability). The results show the potential of rosemary essential oil as an additive for application in food packaging.

Highly antibacterial behavior of casted films for wound dressings based on cellulose acetate containing dual compositions of ZnO and silver vanadate

This study focuses on enhancing the biological activity of cellulose acetate (CA) scaffolds through modifications using zinc oxide (ZnO), silver vanadate (Ag3VO4), and graphene oxide. The aim is to improve the contact angle, cell viability, and antibacterial characterization of the CA scaffold. Notably, the addition of ZnO and Ag3VO4 to the CA film significantly reduces the contact angle from 40.9° ± 3.145–27.11° ± 0.97, indicating improved surface properties. Furthermore, the incorporation of these additives leads to a notable increase in cell viability, reaching approximately 120 % viable cells at a concentration of about 2.44 μg/ml. The modified CA scaffold, particularly with S5 composition, exhibits strong antibacterial activity against E. coli and S. aureus, with measured values of approximately 10.7 % ± 0.4 and 10.75 % ± 0.5 against the control, respectively. Overall, this study highlights the significance of modifying CA scaffolds with ZnO, Ag3VO4, and graphene oxide, presenting advancements in wound healing materials with improved surface properties, enhanced cell viability, and effective antibacterial activity. These findings contribute to the field's knowledge and hold promise for future developments in wound healing applications.

Acetylation of cellulose in ethyl acetate: characterization and thin film applications

The study aims to explore the viability of ethyl acetate as a solvent for cellulose acetylation and assess the feasibility of producing films from the acetylated cellulose. Methodologically, the research focused on limited variations in reaction temperature and catalyst amount, specifically two temperatures and four catalyst quantities, while maintaining consistent quantities of EtoAc and acetic anhydride, reaction time, solution concentration, and other factors. The structure and properties of acetylated cellulose were investigated by titration (heterogeneous saponification), viscosity, chemical resistance (solubility), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), proton nuclear magnetic resonance (1H-NMR) and differential scanning calorimetry (DSC). Surprisingly, efficient acetylation in ethyl acetate was achieved with a small catalyst quantity. As the catalyst amount increased, degree of substitution decreased from 2.32 to 0.76. Further investigation involved the production of thin acetate films using the casting method, and evaluating film properties such as ultraviolet (UV) light absorbance, water vapor permeability, tensile strength, and cross-sectional characteristics via scanning electron microscopy (SEM). The films exhibited impressive tensile strengths, reaching up to 76.98 MPa, and demonstrated exceptional transparency. The findings suggest that EtoAc is a suitable solvent for synthesizing cellulose acetate, and adjustments to reaction variables hold the potential to enhance product qualities.

Photocatalytic Degradation of Polyvinyl Chloride-Vinyl acetate Film Using 5-Phenylazo Salicyaldehyde Derivative

Polymers are employed in a variety of applications that may be harmful to the environment. As a result, the purpose of the research is to dismantle the mutated polymers by inexpensive materials to preserve the environment. To do this, an azole ring in 5-phenylazo salicalicaldehyde derivative was produced and put into a poly (vinyl chloride-vinyl acetate) (PVC-VA) chain by substitution process. The final product was created by adding 5-phenylazo salicalicaldehyde to the priority chemical. Under ultraviolet light irradiation in accelerated settings, the films' resistance to deterioration and IOH,ICO,IC=C were examined using Fourier-transform infrared spectroscopy, viscosity tests , and weight loss to follow the changes caused by UV radiation exposure. The azo compound significantly improved the photo degradation of PVC-VC polymer. When compared to the original polymer.

Properties and environmental sustainability of fungal chitin nanofibril reinforced cellulose acetate films and nanofiber mats by solution blow spinning

Materials from biological origin composed by renewable carbon facilitate the transition from linear carbon-intensive economy to a sustainable circular economy. Accordingly, we use solution blow spinning to develop fully biobased cellulose acetate films and nanofiber mats reinforced with fungal chitin nanofibrils (ChNFs), an emerging bio-colloid with lower carbon footprint compared to crustacean-derived nanochitin. This study incorporates fungal ChNFs into spinning processes for the first time. ChNF addition reduces film surface roughness, modifies film water affinity, and tailors the nanofiber diameter of the mats. The covalently bonded β-D-glucans of ChNFs act as a binder to improve the interfacial properties and consequently load transference to enhance the mechanical properties. Accordingly, the Young's modulus of the films increases from 200 ± 18 MPa to 359 ± 99 MPa with 1.5 wt% ChNFs, while the elongation at break increases by ~45 %. Life cycle assessment (LCA) is applied to quantify the environmental impacts of solution blow spinning for the first time, providing global warming potential values of 69.7–347.4 kg·CO2-equiv.·kg−1. Additionally, this work highlights the suitability of ChNFs as reinforcing fillers during spinning and proves the reinforcing effect of mushroom-derived chitin in bio-based films, opening alternatives for sustainable materials development beyond nanocelluloses in the near future.

Preparation, characterization and decomposition test on Tapanuli organoclay reinforced cellulose acetate/cellulose acetate butyrate blend composites

The need for biodegradable composites has increased for many applications in recent years. Cellulose acetate (CA) and cellulose acetate butyrate (CAB) are relatively easy and cheap to fabricate, as well as relatively easy to decompose compared to other polymers. These materials are transparent and lightweight with low tensile properties. In this current study, the effect of Tapanuli clay addition on tensile and decomposition properties of CA and CA–CAB systems were investigated. Tapanuli organoclay was prepared by a cation exchange treatment using hexadecyltrimethylammonium bromide (HDTMA-Br) surfactant to Na-bentonite. Prior to the treatment, the Tapanuli clay was subjected to purification from organic and carbonate compounds and to balance the cations by homogenizing them into Na+. The basal spacing of Tapanuli clay increased from 1.52 nm up to 1.98 nm. CA and CA −5 wt% CAB composites were then synthesized using a solvent casting method. It was found that the addition of both 5 wt% CAB and 7 wt% organoclay in CA decreased the tensile strength and reduced the mass loss by 70%. After 45 days of the decomposition test, it was indicated that the presence of 5 wt% CAB in CA reduced the mass loss of the system by about 50%. These findings were con-firmed by the Scanning Electron Microscope (SEM) images which showed different patterns of as-synthesized and decomposed materials. In conclusion, the presence of 1 wt% Tapanuli organoclay slightly increased the decomposed mass of CA film and enhanced the tensile strength of CA-co-CAB.

Oleic acid decorated kraft lignin as a hydrophobic and functional filler of cellulose acetate films

The packaging industry has primarily been dominated by single-use, petrochemical-sourced plastic materials despite their short-term use. Their leakage into the ecosystem after their use poses substantial environmental concerns. As a result, compostable and renewable packaging material alternatives are garnering significant attention. Cellulose acetate is a derivative of cellulose that exhibits excellent tensile properties, transparency, melt processability, and intermediate compostability. However, its application in the food packaging industry is limited due to its hygroscopic behavior and lack of dimensional stability. This study investigated using lignin (pristine and esterified) as a functional additive of cellulose acetate. The effect of varying concentrations of pristine kraft and oleic acid functionalized lignin in the cellulose acetate matrix and its effect on the resulting film's mechanical, morphological, viscoelastic, and water barrier properties were explored. Comprehensive characterization of the thermomechanical processed lignin-cellulose acetate sheets revealed reduced moisture absorption, improved UV and moisture barrier, and enhanced tensile properties with melt processability. Overall, the studied films could have appealing properties for food and other packaging applications, thus, serving as eco-friendly and sustainable alternatives to conventional petroleum-derived packing materials.

Structure and functional properties of aluminum hydroxide reinforced bamboo‐derived cellulose acetate composite film for biodegradable packaging

AbstractBiodegradable plastics are gaining popularity as environmentally friendly functional materials. This study focuses on the preparation of aluminum hydroxide (Al(OH)3) reinforced cellulose acetate composite films using a cost‐effective approach. The process involves synthesizing bamboo‐derived cellulose acetate (BDCA), dissolving it in tetrahydrofuran with glycerol as a plasticizer, and incorporating Al(OH)3 particles into the casting solution to reinforce the cellulose acetate film. Analyses on microstructure and characteristics of the films were conducted through various techniques, including scanning electron microscopy (SEM), Fourier transform infrared (FT‐IR) spectroscopy, x‐ray diffraction (XRD), water contact angle measurement, and tensile testing. The results indicate that the Al(OH)3 particles were well‐dispersed in the composite films, leading to a strong interaction with the cellulose acetate matrix. As a result, the prepared composite films exhibited significantly higher tensile strength compared to pure bamboo‐derived cellulose film. Additionally, they demonstrated improved anti‐ultraviolet properties and a lower water vapor transmission rate, despite being more hydrophilic. This method holds significant potential for commercial applications in producing high‐performance cellulose acetate‐based composite films.Highlights Bamboo‐derived cellulose acetate was synthesized through chemical processes. BDCA based composite film reinforced with Al(OH)3 was prepared by casting method. The Al(OH)3 significantly enhance the functional properties of the composite film. Composite films showed good performances for packaging according to the results.

XRD and UV–Vis studies of cellulose acetate film blended with different concentrations of nano-metal oxide

Molybdenum Trioxide nanoparticle (MoO3-NPs) was introduced to Cellulose acetate (CA) biopolymer with different concentration using casting process by dispersed MoO3-NPs [0.0, 0.25, 0.5 and 1.0 wt%]. Molecular structure of samples has been studied using XRD and UV–Vis. the data shown by X-ray results indicated the amorphous nature of the pure polymer. Some peaks are appeared as a result of the addition of MoO3-NPs which indicate that samples were partially crystallized. The crystallite size of nano-metal oxide was calculated for blended samples by Size–Strain Plot method which was found to increase with increasing the concentration of MoO3. UV–Vis results indicate that there exist two indirect energy band gaps; Onset band gap which observed to decreases from 1.3 eV for pure polymer to 0.78 eV for polymer blended with 1.0 wt% MoO3-NPs and HOMO–LOMO band gap which observed to decrease from 3.23 eV for pure polymer to 2.89 eV for polymer blended with 1.0 wt% MoO3-NPs. This indicate that the addition of nano-metal oxide improve the optical conduction of CA. Urbach energy was observed to increase with increasing MoO3-NPs from 0.27 eV for pure CA to 0.32 eV for 1.0 wt% MoO3-NPs concentration which may be occurred due to the creation localized states at the band gap as a result of the addition of MoO3-Nps.

Highly flexible carbon nitride-polyethylene glycol-cellulose acetate film with photocatalytic antibacterial activity for fruit preservation

Cellulose acetate film, as a biodegradable and biomass-derived material, has great potential applications in food packaging. However, the poor mechanical and antibacterial properties limit its applications. Herein, a highly flexible carbon nitride-polyethylene glycol-cellulose acetate (CN-PEG-CA) film was successfully prepared by combining graphitic carbon nitride (g-C3N4) photocatalyst with cellulose acetate (CA). The g-C3N4 enables the film with antibacterial activity, as a green photocatalyst. PEG softens the rigid polymer CA and crosslinks CA, PEG, and g-C3N4 together by hydrogen bonding, as a flexible crosslinker. X-ray diffractometer (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectrum (FT-IR) characterizations confirmed the successful preparation of the CN-PEG-CA film. The mechanical property tests demonstrated that adding PEG increased the elongation at break of the film by about 4 times. The composite film had high antibacterial activity, and the bactericidal rates on Escherichia coli and Staphylococcus aureus were 99.98 % and 99.89 %, respectively. It effectively extended the shelf life of strawberries to 96 h and effectively maintained the quality of strawberries during storage. After 96 h, the weight loss rate of strawberries packaged with 15 % CN-PEG-CA film was 21.83 %, vitamin C content was 45.47 %, titratable acidity content was 0.89 %, and color, hardness and total soluble solids were well maintained. And biocompatibility test results showed that the film was safe and nontoxic. From the ecological and economic point of view, the highly flexible and biodegradable films with efficient photocatalytic antibacterial activity synthesized in this paper have great potential in the field of food packaging.

Reducing reflection of down-shifting solar cells through scattering by particles

The improvement of down-shifting solar cells through reducing the reflection in short wavelength range by scattering is investigated experimentally and theoretically. Such down-shifting solar cells are fabricated by doping Y2O3 particles into down-shifting ethylene vinyl acetate films with CaAlSiN3:Eu2+ phosphors. Experimental results show that the scattering of Y2O3 particles can reduce the reflection of the down-shifting solar cells in the wavelength below 450 nm. It can be attributed to two reasons. The first is that the backscattering in the short wavelength is weaker than that in the middle and long wavelength. The second is that the scattering by Y2O3 particles allows more light reach the phosphors and increases their absorption. This means that more photons with poor spectral responses can be converted into the photons with better spectral responses. This work provides a way to realize simultaneously strengthening the down-shifting effect and suppressing the phosphor-induced reflection and can be used to further improve the down-shifting solar cells.

Study on the behavior of small cracks in PA38-T6 (6060-T6) aluminum alloy under multiaxial fatigue loadings

This study investigated the effects of multiaxial cyclic loading on the initiation and propagation of fatigue cracks in an industrial-grade aluminum alloy. Four different loading cases, including 90° out-of-phase and asynchronous loading, were used under the control of strain. The study used cellulose acetate film replication and SEM fractography techniques to increase the understanding of the evolution of fatigue damage on specimen surfaces. The material exhibited a shear damage mechanism with a significant amount of small cracks coalescence. It was explained why, despite a high agreement with the assumptions of the critical plane approach, the predicted fatigue life was overestimated at high loading levels. A correlation between the crack initiation period and overall fatigue life, regardless of loading case, was presented, which has a potential for practical applications.