Addition Of Cellulose Acetate Research Articles

Dielectric and viscoelastic properties of 3D-printed biobased materials

This study aimed to develop new biobased materials containing plasticized cellulose acetate (CA) by Fused Filament Fabrication (FFF). We investigated the influence of CA on the viscoelastic/dielectric properties and the influence of 3D printing on the dielectric properties of the polymer blends. A microstructural analysis showed that the blends had a strong heterogeneous morphology, as the two phases formed a fibrillar and lamellar structure. CA strongly increased the blend viscosity at 175 °C, multiplying by 100 times the complex viscosity between neat PLA and the blend containing 40% of CA by weight (CA-40). The addition of CA to the blends increased the dielectric constant (ε') and dielectric loss (ε''), as well as the alternative current electrical conductivity (σAC). The dielectric constant of CA (ε'CA) was proportional to its percentage in the blend, showing a behavior analogous to a rule of mixture. Moreover, the activation energy of the electrical conductivity (σDC) measured at T > 124 °C decreased with increasing CA content and was associated with the enhancement of the ionic conductivity provided by the CA and its plasticizer. A decrease in the α-relaxation temperature and the associated activation energy of the PLA was also linked to the presence of the CA plasticizer. Finally, 3D printing greatly decreased both ε', ε'' and σAC due to the internal voids induced by the 3D printing process. The porosity was measured at 12% for neat PLA and between 20% and 25% for the blends. These results showed the advantage provided by FFF technology in the production of PLA:CA blends with controlled dielectric properties, thereby favoring the use of these new materials in key dielectric areas.

Eosin-Y containing electrospun fibers for optical ammonia sensing based on wavelength shift

Sensors in recent days have been in great demand in industrial zones of simple, low-cost sensors for effectively sensing various gases. This research work develops electrospinning fibers for optical ammonia sensing based on the wavelength shift. The optical sensing fibers were produced approach by the electrospinning technique. The addition of cellulose acetate (CA) matrix with doped Eosin-Y is an NH3 fluorophore. The same light emitting diode (LED) light source was used to excite NH3-sensitive dyes at 380 nm peak wavelength. Display the eosin Y emission spectrum, with a maximum wavelength of 582 nanometers. The observed red emission wavelength shift and fluorescence intensity at 582 nm decreased with increasing concentrations of NH3. The emission spectrum of eosin-Y fluorescence at 582 nanometers is changed with increasing NH3 concentrations ranging from 0 to 500 parts per million. In this work, according to the experiment results, the sensitivity of NH3 sensors is 7.73. Finally, the electrospinning fibers for optical NH3 sensing developed as a result of this research enable effective sensing of NH3 concentrations in practical applications in a variety of fields, including medical and industrial.

Thermo-mechanical performance of nanostructured electrospun composites produced from poly(vinyl alcohol) and cellulosic compounds for potential uses as wound dressings

The purpose of this research was to analyze the morphology, thermal and mechanical properties of poly(vinyl alcohol) (PVA)-based electrospun mats reinforced with cellulose acetate (CA) or cellulose nanocrystalline (CNC) for potential applications in wound dressings. Bead-free and water-stable electrospun nanofibers made of blends of PVA and CA or CNC were successfully produced and crosslinked with glutaraldehyde vapor. Crosslinking slightly increased the nanofibers' diameters in order of 43 and 13% for 80/20 PVA/CA and PVA/CNC electrospun mats, respectively, while maintaining their bead-free morphology. Thermogravimetry (TGA) and differential scanning calorimetry (DSC) evaluations were employed to determine the miscibility and the thermal response of the uncrosslinked and crosslinked mats, reporting a reduction in mass loss upon addition of CA and CNC and upon crosslinking process. Polymers' powder and mats (before and after crosslinking) crystallinity was assessed by X-ray diffraction analysis (XRD). Crosslinked mats experienced a slight reduction in crystallinity compared to the uncrosslinked. Static and dynamic tensile strength tests revealed that CA and CNC doped mats enhanced the Young's modulus and lowered deformation at failure compared to pristine PVA electrospun mats. Data from storage modulus (E′) demonstrated the strength of the physical interactions formed between PVA and the cellulosic derivatives (either before and after crosslinking), highlighting the stiffness of CA (231.58 MPa for the 80/20 mat) and, particularly, CNC (742.04 MPa for the 80/20 mat). This research uncovered important information concerning the chemical and physical relation between polymeric matrices and additives, essential for the proper selection of materials for wound dressings production.

Different Kraft lignin sources for electrospun nanostructures production: Influence of chemical structure and composition

This work focuses on the structural features and physicochemical properties of different Kraft lignins and how they can influence the electrospinning process to obtain nanostructures. Structural features of Kraft lignins were characterized by nuclear magnetic resonance, size exclusion chromatography, fourier-transform infrared spectroscopy, and thermal analysis, whereas chemical composition was analyzed by standard method. The addition of cellulose acetate (CA) improves the electrospinning process of Kraft lignins (KL). Thus, solutions of KL/CA at 30 wt% with a KL:CA weight ratio of 70:30 were prepared and then physicochemical and rheologically characterized. The morphology of electrospun nanostructures depends on the intrinsic properties of the solutions and the chemical structure and composition of Kraft lignins. Then, surface tension, electrical conductivity and viscosity of eucalypt/CA and poplar/CA solutions were suitable to obtain electrospun nanostructures based on uniform cross-linked nanofibers with a few beaded fibers. It could be related with the higher purity and higher linear structure, phenolic content and S/G ratios of lignin samples. However, the higher values of electrical conductivity and viscosity of OTP/CA solutions resulted in electrospun nanostructure with micro-sized particles connected by thin fibers, due to a lower purity, S/G ratio and phenolic content and higher branched structure in OTP lignin.

Performance adjustable porous polylactic acid‐based membranes for controlled release fertilizers

AbstractHere, the phase inversion method using a mixture of chloroform and acetone as a solvent was adopted to fabricate a series of porous polylactic acid (PLA)‐based membranes for controlled release fertilizers (CRFs). Cellulose acetate (CA) was used as an additive; polyethylene glycol (PEG) and nano‐SiO2 were used as porogens. Our first interest is to investigate effects of the amount of additive and porogen and type of porogens on the resulting membranes' performance. Results show the dialysis coefficient for membrane M1‐3 (CA content of 2%) is nearly 20 times higher than that for M0‐1 (CA content of 0%), suggesting that the addition of CA can promote the membrane's permeability. Porogens can increase membranes' hydrophilicity, dialysis coefficient and nutrient release rate. However, there is no obvious performance difference between membranes with different porogens. Secondly, M1‐2 (no porogen), M2‐2 (nano‐SiO2 content of 0.5%) and M3‐2 (PEG content of 0.5%) were selected to coat urea granules. Results show the nutrient release rate of urea coated by M2‐2, M3‐2 is much higher than that of urea coated by M1‐2. This research suggests the resulting membranes' performance is easily adjustive and they can be applied to prepare various CRFs to fertilize various crops.

On the Synthesis and Characterization of Polylactic Acid, Polyhydroxyalkanoate, Cellulose Acetate, and Their Engineered Blends by Solvent Casting

In this paper, we report the synthesis of polylactic acid (PLA), polyhydroxyalkanoate (PHA), cellulose acetate (CA), and their binary and ternary blends by solvent casting. PLA, PHA, and CA had tensile strengths of ~ 59.4, ~ 17.4 and ~ 23.9 MPa, respectively. Differential scanning calorimetry (DSC) analysis showed that binary blends of PLA and PHA are immiscible in each other. During mechanical testing, 50 PHA–50 PLA showed mild enhancement and had a tensile strength of ~ 37.8 MPa as compared to 75 PLA–25 PHA and 25 PLA–75 PHA, which had tensile strengths of ~ 31.2 and ~ 22.9 MPa, respectively. This may be due to the formation of crystallized PHA in PLA matrix, which was further supported by the DSC results and analysis of fractured surface of 50 PHA–50 PLA. The addition of 24, 49, 74, and 89.5 vol.% CA in the PHA matrix improved the tensile strength to ~ 25.8, ~ 25.9, ~ 44.9, and ~ 42.4 MPa, respectively. Based on DSC results, it is hypothesized that the strength enhancement is due to synergistic effect of crystallization of PHA and plasticizing effect of CA additions. The addition of CA in PLA caused severe demixing, and the strength of PLA matrix reduced to ~ 25.8 and ~ 21.4 MPa after the additions of 24 and 49 vol.% CA in PLA matrix, respectively. In ternary blends, the addition of 5 and 19 vol.% CA degraded the strength of PHA–PLA to ~ 22.6 and ~ 21.8 MPa, respectively. However, after the addition of higher concentrations of CA, for example 32, 59, and 79 vol.% CA additions in PHA–PLA matrix, the strength improved to ~ 32.9, ~ 39.3, and ~ 32.1 MPa, respectively. The enhancement in strength can be explained by the increase in amorphous nature of these blends, which was further supported by the DSC results.

Applicability of Different Bio-based Polymers for Wiring Boards

The paper gives a review of experiments for the application of biodegradable, sustainable polymers as a wiring board material. In the paper two different biobased materials and the standard PCB materials FR4 and FR2 were compared. The investigations refer to mechanical, electrical performance, surface quality the flammability and applicability for Polymer Thick Film Technology (PTFT) of the biobased material. The biobased materials are polylactic acid (PLA) mixed with different contents of cellulose acetate (CA) or flame retardant zinc pyrophosphate (ZnPP) and polyurethane (PU) with CA. The results show that the addition of CA to the polymers leads to a change of different properties for PLA and to a significant change in mechanical properties for PU. The use of ZnPP in PLA shows major improvements regarding the flammability of the polymer. The properties of the samples are in the same order of magnitude as the properties of FR2.

Preparation and characterization of PES/CA microporous membranes via reverse thermally induced phase separation process

The blend polyethersulfone (PES)/cellulose acetate (CA) flat‐sheet microporous membranes were prepared by reverse thermally induced phase separation (RTIPS) process. The effects of CA content and coagulation bath temperature on membrane structures and properties were investigated in terms of membrane morphology, water contact angle, permeation performance, and mechanical properties. The cloud point results indicated that the cloud point decreased with the increasing content of CA. When the coagulation bath temperature was lower than the cloud point, the membrane formation process underwent nonsolvent induced phase separation (NIPS) process and dense skin layer and finger‐like structure were formed in membranes. These membranes had lower pure water flux and poor mechanical properties. But when the coagulation bath temperature was higher than the cloud point, the membrane formation process underwent RTIPS process. The porous top surface as well as porous cross‐section of the membranes were formed. Therefore, high pure water flux and good mechanical properties were obtained. The contact angles results indicated that the hydrophilicity of the prepared membranes improved obviously with the addition of CA. When the content of CA was 0.5 wt% and the membrane formation temperature was 323K, the PES/CA microporous membrane which was prepared via the RTIPS process displayed a optimal permeability of the pure water flux of 816 L m−2 h−1 and the BSA rejection rate of 49.5%, which showed an increase of 48.9% and 23.6% than that of pure PES membrane, respectively. Moreover, the mechanical strengths of the membranes obtained by RTIPS process were better than those membranes prepared by NIPS process. POLYM. ENG. SCI., 58:180–191, 2018. © 2017 Society of Plastics Engineers

Ionic Conductivity Studies on Magnesium-Based Cellulose Acetate Polymer Gel Electrolytes

Magnesium-based polymer gel electrolytes consist of magnesium triflate (MgTf) salt, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) solvents as well as cellulose acetate as a polymeric agent were prepared via direct dissolution method. The highest ionic conductivity obtained for MgTf-EC:DEC(1: 1) liquid electrolytes was 2. 66 x 10-3 S cm·1 and enhanced to 2.73 x 10-3 S cm·1 with the addition of cellulose acetate. These results were in agreement with the activation energy obtained with the lowest value of 0.11. The best explanation on the enhancement in ionic conductivity of PGE is due to the "breathing polymeric chain model". The plots of conductivity-temperature were shown to obey an Arhenius rule. The electrical properties of the sample with the highest conductivity were analyzed using electrical permittivity-based frequency and temperature dependence in the range of JOO Hz-1 MHz and 303-373K, respectively. The variation in dielectric permittivity (e, and e) as a function of frequency at different temperatures exhibited decays at higher frequencies and a dispersive behavior at low frequencies. Based on the observed electrical properties, it can be inferred that this polymer gel electrolyte could be a promising candidate as an electrolyte in electrochemical devices.

Ionic Conductivity Studies on Magnesium-Based Cellulose Acetate Polymer Gel Electrolytes

Magnesium-based polymer gel electrolytes consist of magnesium triflate (MgTf) salt, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) solvents as well as cellulose acetate as a polymeric agent were prepared via direct dissolution method. The highest ionic conductivity obtained for MgTf-EC:DEC(1: 1) liquid electrolytes was 2.66 x 10-3 S cm-1 and enhanced to 2.73 x 10-3 S cm-1 with the addition of cellulose acetate. These results were in agreement with the activation energy obtained with the lowest value of 0.11. The best explanation on the enhancement in ionic conductivity of PGE is due to the "breathing polymeric chain model". The plots of conductivity-temperature were shown to obey an Arrhenius rule. The electrical properties of the sample with the highest conductivity were analyzed using electrical permittivity-based frequency and temperature dependence in the range of 100 Hz-1 MHz and 303-373K, respectively. The variation in dielectric permittivity (er and ei) as a function of frequency at different temperatures exhibited decays at higher frequencies and a dispersive behavior at low frequencies. Based on the observed electrical properties, it can be infe"ed that this polymer gel electrolyte could be a promising candidate as an electrolyte in electrochemical devices.

The Research of Hydrophilic Modification of PVC/PES Blended Membrane by the Additive of CA

In order to improve the performance of Poly(vinyl chloride)(PVC)/ polyethersulfone (PES) blended membranes, cellulose acetate (CA) was used as a hydrophilic enhancer to blend with PVC and PES for membrane preparation by phase inversion method. In this study, the results of equilibrium water content (EWC), contact angle and X-ray photoelectron spectroscopy (XPS) confirmed the addition of CA could effectively improve the hydrophilicity of PVC/PES blended membrane. It was also found that water flux of PVC/PES/CA blended membranes increased with the increase of CA concentration.

Properties of electrospun PVDF/PMMA/CA membrane as lithium based battery separator

Poly vinylidene fluoride:poly methyl methacrylate:cellulose acetate (CA) at ratios of 100:0:0, 90:10:0, 90:5:5 and 90:0:10 respectively, were successfully electrospun. These membranes were mixed to form a 12 wt% solution prepared with volume ratio 7:3 of DMAc:acetone solvents. These membranes were then analyzed using differential scanning calorimetry, scanning electron microscopy, FTIR, WAXD, pore size, porosity% and electrolyte uptake (EU)%. It was observed that the best absorption results were obtained in the presence of CA. The electrospun membrane at ratio of 90:0:10 was observed with the highest porosity of 99.1 % and EU at 323 %. It also had a 43.6 % crystallinity and a 162 °C melting temperature. It was then concluded that addition of CA improved the separator properties.

Interaction of isothermal phase inversion and membrane formulation for pathogens detection in water

The aim of this study was to explore the utilization of polymeric membrane for bio-sensing application in most efficient and rapid way. Customization of membrane formulation via phase separation study to modify its morphologies and properties enable the detection of different pathogens in a specific manner. Experimental findings (FESEM, through-pore distribution, porosity, capillary flow test and protein binding test) verified the predictions of faster capillary flow time and higher membrane’s protein binding by the addition of cellulose acetate and nitrocellulose to the membrane casting dope, respectively. Throughout the phase separation study, the potential phase behavior was investigated, which was correlating various membrane structures to its performances for potential pathogens detection in water.

Preparation and characterization of sodium caseinate films reinforced with cellulose derivatives

Edible composite films, based on glycerol-plasticized sodium caseinate (SC) and either carboxymethyl cellulose (CMC) or cellulose acetate (CA) fibers, were respectively prepared by suspension casting. The effects of mixing SC with very low amounts (up to 3wt%) of CMC or CA were systematically investigated through changes in morphology, surface hydrophilicity, moisture sorption, water vapor permeability, opacity, dynamic mechanical response and mechanical properties of the films. Incorporation of 3wt% cellulose derivatives into the protein matrix led to slight but measurable decreases of equilibrium moisture contents, achieving reductions of 7.5 and 14.4% for CMC and CA reinforced films, respectively. Besides, the addition of CA contributed to the decrease of water vapor permeability, leading to a 38% falloff at 3wt% filler. Contact angle measurements using a polar solvent ranged from 40° to 29–30° as filler concentration increased, indicating that reinforced films had higher superficial hydrophilicity than neat caseinate ones. Transparency decreased as filler concentration increased: the opacities of the most concentrated samples were 1.9 (CMC) and 2.3 times (CA) higher than that of the SC matrix. Moreover, tensile tests revealed that the addition of cellulose derivatives enhanced the tensile modulus (i.e. an 80% increase with 3wt% CMC) and strength (i.e. a 70% increase with 3wt% CA) although the elongation at break decreased. The differences found in the performance of both cellulose derivatives were explained in terms of water-solubility, hydrophobic character, rigidity of the fibers and quality of the filler dispersion in the protein matrix.

Phase separation and heat-induced gelation characteristics of cellulose acetate in a mixed solvent system

The addition of cellulose acetate (CA) to a mixed solvent of N,N dimethylacetamide (DMA) and water is examined at different CA concentrations and water contents. Unlike the addition of water to a CA/DMA solution, the addition of CA to a DMA/water solution leads to a transition from a homogeneous solution at low water content to a two-phase system at higher water contents. The two-phase system has an upper liquid layer with an almost clear “solution-like” appearance and a lower gel-like layer. Treating the two-phase system at 100 °C for 30 min results in the formation of a uniform gel structure, similar to that produced by directly adding water to a CA/DMA solution. Although the phase behavior of these systems is similar, their viscoelastic properties are not. The moduli of the heat treated gels do not significantly vary from that of the bottom gel-like portion of the original two-phase samples. This may indicate that thermal treatment at 100 °C is not able to disrupt the pre-established CA intra- and intermolecular interactions and form the stronger CA-DMA interactions.

Remarkable improvement of the performance of poly(vinylidene fluoride) microfiltration membranes by the additive of cellulose acetate

Abstract In order to improve the performance of poly(vinylidene fluoride) (PVDF) microporous membranes, cellulose acetate (CA) was used as a hydrophilic additive to blend with PVDF for membrane preparation by phase inversion in a wet process. Scanning electron microscopy (SEM) revealed that the fabricated PVDF membranes have the typical asymmetric structure. The water contact angles of the PVDF membranes were decreased, the water contents of the membranes were increased, and the amounts of adsorbed protein were dramatically decreased due to the addition of CA. X-ray photoelectron spectroscopy (XPS) analysis confirmed the enrichment of CA segments on the PVDF membrane surfaces due to surface segregation for lowering of interface free energy. The shift of F 1s binding energy from 687.8 to 687.0 eV indicated that there are interactions between PVDF and the added CA. All prepared PVDF microfiltration membranes have higher flux recovery ratio and lower membrane fouling in protein separation and purification.

Electrospun Activated Carbon Nanofibers Electrodes Based on Polymer Blends

Activated carbon nanofibers (ACNFs) based on a polymer blend, which consists of polyacrilonitrile (PAN) and cellulose acetate (CA), were prepared by electrospinning and subsequent thermal treatment. The diameter of ACNF increased with increasing CA content. The electrical conductivity increased with the addition of CA due to a larger oxygen amount of CA molecules. The specific surface area and average pore diameter of CA-free ACNF (CP) were and , respectively, while those of CA-blended ACNF (15CP) increased to and , respectively. The capacitance of CP was at , whereas that of 15CP increased to . This is why the CP is predominated by small surface area with microporosity, whereas the 15CP is affected by higher surface area with better mesoporosity due to the combination of electrospinning based on polymer blends and thermal treatment.

Structure and properties of composites of polyethylene or maleated polyethylene and cellulose or cellulose esters

AbstractComposites of linear low‐density poly(ethylene‐co‐butene) (PE) or maleated linear low‐density poly (ethylene‐co‐butene) (M‐PE) and cellulose (CEL), cellulose acetate (CA), cellulose acetate propionate (CAP), or cellulose acetate butyrate (CAB) were prepared in an internal laboratory mixer with 20 wt % polysaccharide. The structure and properties of the composites were studied with tensile testing, dynamic mechanical thermal analysis, differential scanning calorimetry, extraction with a selective solvent, Raman spectroscopy, and X‐ray diffraction. Composites prepared with M‐PE presented yield stress and elongation values higher than those of composites prepared with PE, showing the compatibilizer effect of maleic anhydride. Dynamic mechanical thermal analysis performed for M‐PE–CEL, M‐PE–CA, M‐PE–CAP, and M‐PE–CAB composites showed one glass‐transition temperature (Tg) close to that observed for pure M‐PE, and for M‐PE–CAP, another Tg lower than that measured for the polysaccharide was observed, indicating partial mutual solubility. These findings were confirmed by the extraction of one phase with a selective solvent, gravimetry, and Raman spectroscopy. X‐ray diffraction showed that the addition of CEL, CA, CAP, or CAB had no influence on the lattice constants of PE or M‐PE, but the introduction of the reinforcing material increased the amorphous region. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:402–411, 2007

Thermal, mechanical and morphological analysis of poly(ε‐caprolactone), cellulose acetate and their blends

AbstractPoly(ε‐caprolactone) (PCL), cellulose acetate (CA) and their blends were characterized by their tensile strength, differential scanning calorimetry (DSC) and optical microscopy (OM). The compatibility of the blends was investigated and the OM results showed that CA tended to disperse as discrete particles in PCL. Thermal analysis showed the characteristic melting temperature peaks for PCL and CA in all blends, indicating that the compounds were immiscible. The addition of CA to PCL increased slightly the crystallinity of PCL, decreased the elongation at yield and the tensile strength up to 40/60 PCL/CA (w/w), which suggested incompatibility between the polymers. Together, these results indicate the absence of a strong chemical interaction between the two polymers. In agreement with this, the addition of CA to blends with PCL increased Young's modulus. Copyright © 2003 John Wiley & Sons, Ltd.