Cellulose Acetate Blend Research Articles

Preparation and characterization of compatibilized and toughened polylactic acid/cellulose acetate films by long‐chain hyperbranched polymers

AbstractA type of long‐chain hyperbranched polymers (LCHBPs) was prepared by grafting hydroxyl‐terminated flexible long chain onto hyperbranched polymers (HBPs). The structure of LCHBPs was confirmed by Fourier transform infrared (FT‐IR) and nuclear magnetic resonance (1H‐NMR) analysis. It was then used as the modifier for toughening and compatibilizing the polylactic acid (PLA)/cellulose acetate (CA) blends. Upon the addition of LCHBPs, the compatibility between PLA and CA was improved, the dispersion of CA particles in PLA matrix was more uniform, and the brittle‐ductile tear transition of the PLA/CA blends was occurred. The crystallization of PLA was promoted by the addition of LCHBPs. By adding LCHBPs, glass transition temperature and cold crystallization temperature were reduced, the crystallizability was enhanced, and the crystallization temperature range was expanded. The thermal decomposition temperature of the PLA/CA was found increased with the addition of LCHBPs. When the content of LCHBPs was 1 phr, the elongation at break and the tear strength of the PLA/CA blends were increased by 484% and 38.24%, respectively. Meanwhile, the thermal stability and hydrophilic properties of the blend films were improved by adding LCHBPs.

Synthesis and Characterization of Blended Cellulose Acetate Membranes.

The casting and preparation of ultrafiltration ZnO modified cellulose acetate membrane (CA/ZnO) were investigated in this work. CA membranes were fabricated by phase inversion using dimethylformamide (DMF) as a solvent and ZnO as nanostructures materials. Ultrafiltration (UF) performance, mechanical stability, morphology, contact angle, and porosity were evaluated on both CA- and ZnO-modified CA samples. Scanning electron microscopy (SEM) was used to determine the morphology of the membranes, showing different pore sizes either on rough surfaces and cross-sections of the samples, an asymmetric structure and ultra-scale pores with an average pore radius 0.0261 to 0.045 µm. Contact angle measurements showed the highest hydrophobicity values for the samples with no ZnO addition, ranging between 48° and 82.7° on their airside. The permeability values decreased with the increasing CA concentration in the casting solution, as expected; however, ZnO-modified membranes produced lower flux than the pure CA ones. Nevertheless, ZnO modified CA membranes have higher surface pore size, pore density and porosity, and improved surface hydrophilicity compared with pure CA membranes. The results indicated that the incorporated nano-ZnO tends to limit the packing of the polymer chains onto the membrane structure while showing antifouling properties leading to better hydrophilicity and permeation with consistent UF applications.

Improvement efficiency of the of poly (ether-block-amide) -Cellulose acetate (Pebax-CA) blend by the addition of nanoparticles (MIL-53 and NH2-MIL-53): A molecular dynamics study

Improvement efficiency of the of poly (ether-block-amide) -Cellulose acetate (Pebax-CA) blend by the addition of nanoparticles (MIL-53 and NH2-MIL-53): A molecular dynamics study

Coating characterization by hyperspectroscopy and predictive dissolution models of tablets coated with blends of cellulose acetate and cellulose acetate phthalate.

The objective of current research was to develop the models of dissolution prediction of tablets coated with cellulose acetate (CA 320S or CA 398-10) and cellulose acetate phthalate (C-A-P) blends. Independent variables selected were coating percent (X1) and percent of CA 320S or CA 398-10 (X2) in the blend. Dependent variables selected were dissolution in 1 (Y1), 8 (Y2), and 24 h (Y3). Diclofenac sodium core tablets were coated with blend of either CA 320S and C-A-P or CA 398-10 and C-A-P at approximately 5, 7.5, and 10% weight gain. CA 320S and CA 398-10 content in the corresponding blends varied from 33.3-66.7% and 25.0-50.0% relative to C-A-P, respectively. Dissolution was performed in phosphate buffer 6.8 using USP apparatus 2. Coated tablets were also characterized for surface morphology and coating uniformity by near infrared hyperspectroscopy. Y1, Y2, and Y3 were statistically (p < 0.05) affected by X2 in CA 320S/C-A-P and CA 398-10/C-A-P blends coated tablets. On the other hand, X1 had statistically significant (p < 0.05) effect only on the Y3 in CA 320S/C-A-P while Y1 was statistically (p < 0.05) affected by X2 in CA 398-10/C-A-P. Analysis of variance also indicated statistically significant (p < 0.05) effect of the studied variables on the dependent variables for both the blends. The models were verified by independent experiment. Model predicted and empirical values of Y1, Y2, and Y3 were close with maximum residual of 7.0%. In conclusion, dissolution can be modulated by varying composition of blend, polymer type, and coating weight.

Highly porous cellulosic nanocomposite membranes with enhanced performance for forward osmosis desalination

Novel highly porous cellulose triacetate (CTA)/cellulose acetate (CA) blends were fabricated as flat sheet membranes, for water desalination using the forward osmosis (FO) procedure. Maleic acid (MA) was used as a pore-forming additive and as a polymeric modifier in combined casting. The aluminum oxide nanoparticles (Al2O3) (NPs) were used for the modification of MA/CTA/CA membrane performances. The synthesized FO membranes are characterized by FTIR spectroscope, contact angle measurement, membrane porosity, SEM, AFM, and mechanical properties. The Al2O3/MA/CTA/CA nanocomposite (NC) modified membrane showed a higher water flux of 27.1 L/m2 h, reverse solute flux of 10.3 g/m2 h, and lower salt rejection of 99.15% using 1 M NH4Cl water solution as the draw solution and 0.1 M NaCl as feed solution. The Al2O3/MA/CTA/CA nanocomposite modified membrane shows a higher porosity (60.3 ± 2), a lower contact angle (55°), and its reduced structural parameter (S) to 0.87 mm. The results revealed that the Al2O3/MA/CTA/CA nanocomposite modified membrane showed the highest water flux using 1 M of the KCl and NH4Cl (20 L/m2 h); followed by (NH4)2SO4 (19.7 L/m2 h) and K2HPO4 (17.6 L/m2 h) as draw solutions (DS) under the FO approach and using natural groundwater sample collected from Al-Zafer village, Sidi Barrani Area, north-western coast of Egypt with salinity of 8536 mg/L as feed solution (FS). It was revealed that the synthesized Al2O3/MA/CTA/CA nanocomposite modified membrane has great potential for application of FO process in brackish water desalination. The current cost per m2 of an Al2O3/MA/CTA/CA nanocomposite modified membrane is AU$ 32/m2 when compared with the commercial FO membrane (AU$ 188/m2).

Improvement of filtration performance of polyvinyl chloride/cellulose acetate blend membrane via acid hydrolysis

AbstractBased on the hydrophilicity and biodegradability of cellulose acetate (CA), polyvinyl chloride (PVC)/CA blend membrane was prepared by solution comixing and phase transformation method. Then the CA in the blend membrane was partially hydrolyzed under acidic conditions to improve the hydrophilicity of the blend membrane, so as to improve the filtration performance of the PVC/CA blend membrane. The properties of the membranes were systematically characterized by Fourier transform infrared spectroscopy, differential scanning calorimeter, and scanning electron microscopy (SEM). The porosity, water contact angle, pure water flux (PWF), protein retention rate, and mechanical properties of the membrane were measured, and the effect of hydrolysis on the filtration performance of the blend membrane was analyzed. The results showed that the hydrophilicity and porosity of the blend membrane increased, the PWF and protein rejection rate enhanced after acid catalyzed hydrolysis, while the mechanical properties of PVC membrane were maintained. This simple preparation method endows PVC/CA blend membrane with desirable filtration performance, and also helps to overcome the disadvantages of poor hydrophilicity and easy pollution of pure PVC membrane.

High performance compatible thiazole-based polymeric blend cellulose acetate membrane as selective CO2 absorbent and molecular sieve

Green blend membranes comprise of high thermal resistance ortho-linked thiazole-based polyimine (PM-4) including thioether linkage were fabricated in combination of glassy cellulose acetate (CA). The thermal stabilities of PMs were examined using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Morphological aspects and functional groups of the membranes were investigated via field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy–attenuated total reflectance (FTIR-ATR) analysis respectively. X-ray diffraction (XRD) and mechanical strength were determined as well. The effects of polyimine content, pressure and temperature were studied on CO2 permeability (P) and selectivity. The pressure changes revealed exponentially increases on CO2 permeability by plasticization, facilitated transfer and solution-diffusion mechanisms, but decreases on CH4 and N2 permeations. Remarkable permeation (P = 3000 Barrer) of CA/PM-4 (1:3 % w/w) and ideal selectivity ratios of CO2/N2 = 59, CO2/CH4 = 33.7 were obtained at 3 bar and 35 °C versus neat CA membrane.

Preparation and characterization of porous polyethersulfone (PES) membranes with improved biocompatibility by blending sulfonated polyethersulfone (SPES) and cellulose acetate (CA) – A comparative study

The current study focuses on the effective sulfonation of polyethersulfone (PES) polymer to synthesize sulfonated-polyethersulfone (SPES) and blending with PES to prepare SPES/PES blend membranes as well as preparation of cellulose acetate CA/PES blend membranes. FTIR-ATR technique was used to confirm the blending of SPES and CA into PES matrix. Water contact angle studies showed a significant reduction of hydrophobicity in SPES blend membranes (49.55 ± 1.52°) as compared with CA blend membranes (59.42 ± 2.20°) and PES base membranes (67.80 ± 1.48°). The presence of pores were analysed using scanning electron microscopy (SEM) where significant changes in the membrane morphology in the blend membranes were observed. Platelet adhesion, protein adsorption and activated partial thromboplastin time (APTT) studies were used to assess hemocompatibility of the membranes in which SPES/PES membranes exhibited improved characteristics as compared with its counterparts. The cytocompatibility of membranes were evaluated using water soluble tetrazolium (WST) assay which confirmed that both SPES/PES and CA/PES blend membranes exhibit better cytocompatibility than base PES membrane

Preparation and Characterisation of Blend Cellulose Acetate Membrane for CO2/N2 Separation

Preparation and Characterisation of Blend Cellulose Acetate Membrane for CO2/N2 Separation

Suppressed crystallization and enhanced gas permeability in thin films of cellulose acetate blends

Film thickness and blending can affect crystallization and chain dynamics of semi-crystalline polymers, particularly for submicron films. Herein we apply these insights to elucidate a long-standing puzzle for industrial asymmetric membranes for CO2 removal from natural gas, which are based on blends of cellulose diacetate (CDA with a degree of acetylation or DS of 2.45) and cellulose triacetate (CTA with a DS of 2.87). The asymmetric membranes comprise thin selective layers (~100 nm) and have been reported to exhibit gas permeability much higher than the bulk blends. We hypothesize that the film thickness and blending confine crystallization and decrease the crystallinity, increasing gas permeability while retaining high selectivity. Specifically, we systematically determined crystallinity for CTA and two blends with various thicknesses ranging from ≈500 nm to ≈20 μm. Adding 75 mass% CTA in CDA (CDA-CTA75) decreases the crystallinity from 34 vol% to 23 vol% at ≈ 20 μm (accompanied by CO2 permeability increase from 3.9 Barrer to 7.1 Barrer), while decreasing the film thickness of CDA-CTA75 from ≈20 μm to ≈ 1.0 μm decreases the crystallinity from 23 vol% to 13 vol% and increases CO2 permeability from 7.1 Barrer to 14 Barrer. Understanding polymer chain dynamics and crystallization in thin films can be instrumental in designing high-performance membranes for industrial gas separations.

Cellulose Acetate of Rice Husk Blend Membranes: Preparation, Morphology and Application

Cellulose acetate blend membranes in this study synthesized from cellulose acetate (CA) of rice husk and NaA zeolites (Z) with N,N’-Methylene bis acrylamide (MBA) as cross-linker agent and gamma-rays from cobalt-60 source as a reaction initiator. Application of the membrane was carried out to increase the concentration of vetiverol in vetiver oil. The steps in this study were isolation the cellulose rice husk with alkali treatment, delignification, acetylation, preparation the cellulose acetate-NaA zeolites NaA-membrane by inverse phase technique, addition N,N’-Methylene bis acrylamide, and irradiation by gamma-rays. Swelling degree, crosslinking yield, tensile strength, membrane performance, FTIR, and SEM analysis were observed. The results obtained that the optimal irradiation dose for synthesis CA-Z-MBA membrane is 20 kGy. The CA-Z-MBA membrane has swelling degree of 4.44%, the tensile strength of 656.40 kg/cm2, and crosslinking yield of 6.61%. Performance of the CA-Z-MBA membrane reached the flux of 60.58 g/m2.h, and permeate concentration (CP) of 11.67%, the CP increase 5 times from 2.40% to 11.67%.

Optimization of the formulation of an original hydrogel-based bone cement using a mixture design

Highly swelling polymers, i.e. superabsorbent hydrogels, are hydrophilic, three dimensional networks that can easily absorb a significant amount water, fluid or drug. They are widely used in various applications such as foods, cosmetics, and medical devices.Bone cements are used in orthopaedics as a filling biomaterial or as a grout enhancing the embedding of a prosthesis into bone and fixation is achieved by mechanical interlock with metal or bone surfaces. Recently, hydrophilic bone cements have attracted the attention for bone tissue-engineering applications.Here a bone cement containing an acrylic hydrogel (HEMA) as a liquid phase and a blend of corn starch, cellulose acetate and bioceramic filler as a solid phase is investigated by means of a mixture design which is a special topic within statistical Design of Experiments (DoE). Output variables of interest, complex shear modulus, compressive modulus and swelling rate related to rheological, mechanical and swelling properties respectively, are measured for each cement formulation.Applying the mixture design strategy enables to assess the impact of the three powder components on each variable of interest and to determine the optimal formulation in order to achieve the required properties of this HEMA-based bone cement, especially the rheology adapted to the desired clinical application, but also appropriate mechanical and swelling properties.

Blend cellulose acetate butyrate/functionalised multi-walled carbon nanotubes mixed matrix membrane for enhanced CO2/N2 separation with kinetic sorption study

Abstract The significant breakthroughs of the membrane technology, specifically the blend mixed matrix membrane (MMM) has revealed a promising carbon dioxide (CO2)/nitrogen (N2) separation performance. In this study, the blend MMMs were prepared by incorporating the functionalised multi-walled carbon nanotubes (MWCNTs-F) as inorganic dispersant into the CAB blend polymer matrix. The blend MMMs were fabricated by blending CAB at molecular weight (Mn) of 70,000 with CAB Mn of 12,000 (M1), 30,000 (M2) and 65,000 (M3). It was found that M2 presented the highest CO2/N2 selectivity of 17.09 ± 1.29 with a CO2 permeance of 341.15 ± 1.19 GPU. The high CO2 permeance for M2 was subsequently a result of the compatible combination between the CAB polymers (Mn of 70000:30000). The blending of CAB polymers demonstrated enhanced functional groups and lowered the chain spacing of the blend MMM. Moreover, through the kinetic sorption study M2 was capable of achieving a moderate solubility coefficient of 7.58 × 1012 cm3 (STP)/cm4 cmHg. In addition, M2 was able to achieve a composition selectivity of 7.85 ± 1.48 from the binary gas permeation study with a feed composition of 50:50 for CO2/N2. From this study, the newly synthesised blend MMM proved to possess excellent CO2/N2 separation performance and revealed that an effective selection of polymer at different molecular weights plays an important role in the fabrication of the blend MMM.

Fe–Al–Mn@chitosan based metal oxides blended cellulose acetate mixed matrix membrane for fluoride decontamination from water: Removal mechanisms and antibacterial behavior

The scientific community is yet to find a cost-effective solution for the widespread problem of fluoride contamination in groundwater. In this study, cellulose acetate based mixed matrix membrane (MMM) was prepared through a phase inversion method using mixed metal oxides nanoparticles-polymer composite (Fe–Al–Mn@chitosan) as nanofiller. Adsorption is the commonly known mechanism of fluoride removal through MMMs and also a reason for its limited performance in real applications. Fe–Al–Mn@chitosan loaded cellulose acetate-based mixed matrix membrane (1 m2) is capable to treat 4000 L fluoride contaminated water. It has been observed that fluoride ions rejection occurs initially through adsorption. Subsequently, membrane surface experiences electrostatic repulsion due to the development of negative surface charges. Excellent defluoridation performance was obtained due to the electrostatic repulsion between F− and negatively charged MMM surface. The antibacterial test reveals that the MMM is less susceptible to microbial attack compared to cellulose acetate membranes. Fluoride rejection through membrane confirms that mixed oxide nanoparticles-polymer-composite loaded MMM is capable of removing F− from water quite efficiently.

Sustainable PHBV/Cellulose Acetate Blends: Effect of a Chain Extender and a Plasticizer

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and cellulose acetate (CA) were blended in the presence of a plasticizer, i.e., triethyl citrate (TEC), and a chain extender, i.e., poly(styrene-acrylic-co-glycidyl methacrylate). To increase the ductility and impact properties of PHBV and to investigate a new biodegradable PHBV-based blend for sustainable packaging, CA was compatibilized with TEC. PHBV and plasticized CA (pCA) blends showed complete immiscibility through separate glass transition and melting peak temperatures in differential scanning calorimetry (DSC), despite the similar Hansen solubility parameters of PHBV, CA, and TEC, indicating partial miscibility. Phase separation between PHBV and pCA was clearly observed by scanning electron microscopy (SEM). PHBV/pCA (70:30) blends had improved impact strength, exceeding that of neat PHBV and pCA, which is attributed to PHBV porosity induced by degradation from the high processing temperature. During processing, the plasticizer migrated from CA to PHBV and partially plasticized it, as evidenced through DSC analysis. The melt temperature of PHBV was reduced, which was confirmed by double melting peaks, representing the formation of secondary crystallites at a lower temperature. Due to processing at high temperatures (210–220 °C), significant porosity was observed in the PHBV/pCA 30:70 blend in SEM analysis. Consequently, the impact strength was improved by 110% as compared to that of virgin PHBV. The addition of CE had no effect on the mechanical properties but did make the PHBV/pCA blends morphologically uniform.

Thermo-mechanical properties and blend behaviour of cellulose acetate/lactates and acid systems: Natural-based plasticizers

This work brings together thermo-mechanical and structural information for plasticized cellulose acetate (CA) by lactates and octanoic acid. CA are processed with plasticizer due to their high Tg and their strong H-bonding network. We prepared CA / plasticizer blends by corotative twin screw extruder and by solvent casting methods. The study of the different relaxations and of the glassy zone modulus was performed by dynamic mechanical analysis (DMA). The miscibility range of cellulose acetate blends were identified by the analysis of the tan δ. Depending on the composition of the system, one or two transitions are noted, this last result indicates the presence of a phase rich in CA and another in plasticizer. To connect this information to crystallinity and molecular organization, X-ray diffraction analyses were carried out. The disappearance of crystallinity allows the plasticization of previously inaccessible zones, causing a glassy modulus drop of more than 1000 MPa.

Preparation and characterization of nano δ‐MnO2‐blended cellulose acetate membrane

AbstractThe ultrafiltration‐adsorption membrane of nano δ‐MnO2‐blended cellulose acetate was synthesized by physical blending technique via the phase inversion method. The MnO2 nanoparticles were loaded into the cellulose acetate polymer matrix for enhancing adsorption. Particularly, dimethyl sulfoxide, a green solvent was used for membrane fabrication. The prepared membranes were characterized by Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM) with energy‐dispersive X‐ray spectroscopy (EDX) and element mapping, atomic force microscopy (AFM). The contact angle and water flux were measured for filtration performance of obtained membranes.

Phenol Removal by Novel Choline Chloride Blended Cellulose Acetate-Fly Ash Composite Membrane

A novel composite membrane (CM) was prepared by coating choline chloride (ChCl) blended cellulose acetate (CA) on fly-ash based ceramic substrate for phenol removal. Different amount (0-1 g) of ChCl was blended with CA to synthesize various CMs. Amount of ChCl in CA increases the contact angle, average pore radius, permeability of CM from 55.15° to 71.55°, 1.6 to 6.83 nm and 0.0057 to 0.0152 L·m−2·h−1·kPa−1, respectively. Phenol rejection increased from 56 to 93 % while increasing ChCl amount in CA. Phenol removal decreased from 94.26-64.23 % and 91.09-78.62 % with increase in applied pressure (69-483 kPa) and feed concentration (50-200 mg·L−1). However, removal rate increased from 80.46-92.47 % with increase in pH 2-12. Among all CMs, CC5 is identified as best CM with maximum phenol removal efficiency (92.7 %) and flux (1.86 L·m−2·h−1) at 207 kPa applied pressure and 100 mg·L−1 of feed phenol concentration. The obtained results reveal that blending of 0.9 % ChCl with CA can significantly enhances the phenol removal efficiency and this could be used as potential CM for treatment of phenol bearing wastewater.

Simultaneous regeneration of calcium lactate and cellulose into PCL nanofiber for biomedical application

Synthetic polymers are easy to process and have excellent mechanical properties but low wettability and poor cell compatibility limit their applications in tissue scaffolding. In this study, a facile procedure was established to regenerate cellulose and calcium lactate (CaL) into a polycaprolactone (PCL) nanofibrous scaffold for tissue engineering applications. Briefly, varying amounts of lactic acid (LA) was mixed with the blend of PCL and cellulose acetate (CA) solutions and electrospun to fabricate an optimal composite PCL/CA/LA fibrous membrane. Later on, as-prepared membranes were treated with calcium hydroxide solution. This process simultaneously converted CA and LA contents into Cellulose and CaL, respectively. In situ regeneration of Cellulose and CaL into the composite fiber remarkably enhanced the biological and physicochemical properties of the composite fiber. This work provides a novel dual-channel strategy for simultaneous regeneration of biopolymer and bioactive molecule into the PCL nanofiber for regenerative medicine and tissue engineering applications.

Improved Impact Properties in Poly(lactic acid) (PLA) Blends Containing Cellulose Acetate (CA) Prepared by Reactive Extrusion.

Poly(lactic acid)/triacetine plasticized cellulose acetate (PLA/pCA) blends were prepared by extrusion at two different temperatures and tetrabutylammonium tetraphenyl borate (TBATPB) was added as a transesterification catalyst to reactively promote the formation of PLA-CA copolymer during the reactive extrusion. The occurrence of chain scission in the PLA phase and branching/crosslinking in the CA phase in the presence of TBATPB, resulting also in a darkening of the material, were demonstrated by studying torque measurements and by performing proper thermogravimetric tests on CA with the different additives. Tensile and impact tests onto the blends prepared at the lower temperature showed better properties than the ones obtained at a higher temperature. Then, the mechanical properties of PLA/plasticized cellulose acetate (pCA) blends prepared at the lower temperature were investigated as a function of the content of plasticized CA in the blend. A range of compositions was observed where blends exhibited improved impact properties with respect to pure PLA without a significant decrease in their elastic modulus. The study of the phase morphology of the blends revealed that the occurrence of reactive compatibilization did not significantly affect the phase distribution. In general, fibrillar CA particles were formed in the PLA matrix during extrusion, thus allowing the preparation of CA fibre reinforced composites. The trend of morphology as a function of the composition and processing conditions was then discussed by considering the evolution of phase morphology in immiscible polymer blends.