Cellulose Diacetate Fibers Research Articles

Synthesis and Application of N-methylphthalimidylazo Disperse Dyes to Cellulose Diacetate for High Wash Fastness.

Cellulose diacetate fibers were prepared from cellulosic biomass with high α-cellulose contents such as purified cotton linters and wood pulps. Cellulose diacetate fibers are sensitive to alkaline solution, which causes hydrolysis of the acetate ester to hydroxyl groups, especially at high temperatures. Thus, the low alkali-resistance of cellulose acetate fibers makes it difficult to achieve high wash fastness by restricting the application of intense after-treatment, such as reduction clearing. A series of N-methylphthalimide-based high-washable azo disperse dyes were synthesized and their dyeing and fastness properties on cellulose diacetate fabrics were investigated. From the overall results obtained in this study, N-methylphthalimidylazo disperse dyes are expected to be a desirable alternative to high value-added dyes that can be used for high color fastness dyeing of cellulose diacetate with a minimal discharge of wastewater during washing process.

Synthesis of High-washable Phthalimide-based Azo Disperse Dyes and the Application of These Dyes on Cellulose Diacetate Fibers

Synthesis of High-washable Phthalimide-based Azo Disperse Dyes and the Application of These Dyes on Cellulose Diacetate Fibers

Blocking and Filtering Effect of Filter Tips of Natural Fibers against Mainstream Cigarettes Smoke

ABSTRACT Conventional cellulose diacetate filter tips of cigarette (CDFTC) are poor filtration performance of toxic compounds. However, environmentally benign filter tips can be made by replacing cellulose diacetate fibers with various types of natural fibers. In the present work, the blocking and filtering effect of natural fibers such as cotton and wool was examined with regards to the polycyclic aromatic hydrocarbons (PAHs) present cigarette smoke. Using various techniques, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Fluorescence detection, the blocking and filtering mechanisms were investigated in detail. The results showed that compared with CDFTC, the filter tips made from natural fibers (cotton or wool) were investigated superior at filtering out toxic particles, which is mainly due to the natural twist or crimp along with their longitudinal directions. The efficiency of PHAs removal by the cotton and wool fibers reached 71.0% (with absorption of up to 71.0 µg cig−1) and 60.5% (with absorption of up to 60.5 µg cig−1), respectively. Compared with the Zhongnanhai filter tip used in this study (54.0%), the filtration efficiency of the cotton and wool fibers was increased by 17.0% and 6.5%, respectively.

Cellulose acetate fibers with improved mechanical strength prepared with aqueous NMMO as solvent

Cellulose diacetate (CA) was successfully dissolved in N-methylmorpholine N-oxide aqueous solution (NMMO·H2O). The CA degraded little during the dissolving process and the homogenous CA/NMMO·H2O solutions were obtained even when the concentration was up to 18%. From the rheological behavior of the CA/NMMO·H2O solution, it was found that the viscosity of the solution was lower than that of lyocell solution, which is due to the lower degree of polymerization and the substitute of acetyl group. Then CA fibers were prepared by dry-jet wet spinning process. The tenacity and the E-modulus of the regenerated CA fibers were up to 3.0 cN/dtex and 75 cN/dtex respectively, and the former was larger than that of industrial CA fibers prepared by dry spinning process. This is related to the structure of the CA fibers, because the crystallinity, crystal orientation of the fibers can be improved by high draw ratio during dry-jet wet spinning process. Otherwise, the CA fibers showed no fibrillation tendency, which showed improved wearing comfort compared to lyocell fibers. This work provided an effective way to produce new CA fibers with higher tensile strength.

Preparation of cellulose diacetate/cellulose hybrid fiber by dry-jet wet spinning in tetrabutylammonium acetate/dimethyl sulfoxide solvent

Cellulose diacetate (CDA)/cellulose hybrid fibers with nice properties were prepared by dry-jet wet spinning using a tetrabutylammonium acetate/dimethylsulfoxide system as a solvent at 50 °C. Scanning electron microscopy (SEM) images exhibited the hybrid fibers with circular cross section and smooth surface. In addition, SEM and Fourier transform infrared spectroscopy analysis indicated the nice compatibility of CDA and cellulose. The hybrid fibers with the addition of CDA showed higher thermal stability and a wider range of degradation than pure cellulose material. It was found that the elongation at break of the fibers increased from 4.87 to 13.22% with increasing CDA/cellulose ratio from 0 to 4:6, which was comparable with CDA fiber spun from 1-butyl-3-methylimidazolium chloride. The 1095.5/cm Raman characteristic band of the hybrid fibers with lower intensity was observed, while it did not towards a higher wave number compared to that of fibers containing less CDA. In addition, the shear viscosity of the solutions exhibited a character of typical shear-thinning behaviour with variation of shear rates.

Improving the mechanical properties of cellulose diacetate fibers via using an ionic liquid as processing solvent

CDA fibers with improved mechanical properties via using [BMIM]Cl ionic liquid which can be directly used for the production of fabric yarns and garments were fabricated and characterized.

Study on pressure drop of cellulose diacetate spinning dope through regular triangular spinneret orifice

Cellulose diacetate (CDA) fiber used in cigarette tow is typically spun using a spinneret with triangular shaped cross section. The properties of the CDA fibers obtained by spinning are influenced by the interplay of various parameters, with the pressure drop being one of the most important parameters. In this paper, we have developed a pressure drop model based on the rheological information and second-type surface integrals. Meanwhile, we also experimentally determined the pressure drop of the CDA spinning dope derived from the wood pulp after pre-treatment, acetification and hydrolysis, on the basis of the differential pressure transducers mounted between the entry and exit of the spinneret with a triangular-shaped orifice. To compare the calculated and experimental results of the pressure drop, the apparent viscosity of the CDA spinning dopes with different mass concentrations was determined using a Physica MCR101 rheoviscometer. In addition, the flow rate of the spinning dopes through the orifices was determined to reveal the variations in pressure drop as a function of dope temperature, mass concentration and shearing rate. Results indicated a decrease in pressure drop with increase in dope temperature and shear rate. However, the pressure drop showed an incremental trend with flow rates or dope concentrations. The experimental data of pressure drop were in the good agreement with those calculated using the model, with deviations of less than ±8 %. The results obtained in this study can serve as a basis for understanding the various parameters controlling the spinning process.

Polysaccharide Fibers as Matrices for Solid-Surface Fluorescence

Fibers of cellulose diacetate (CDA) and chitosan (CTS) of polycationic and polybasic forms were tested as matrices for solid-surface fluorescence (SSF) of several fluorescent probes—eosin Y, trypaflavine, and pyrene. The morphology and surface potential of these matrices were examined. The influence of structural and energetic characteristics of the fibrous polysaccharide materials at SSF of the probes was shown. Fluorescence was studied in aqueous solutions of eosin Y and trypaflavine, in water-ethanolic and water-micellar surfactant media of pyrene, before and after dynamic sorption of the dyes on fibers and in the adsorbed state. The surface of CDA fiber was shown to be capable of sorbing trypaflavine from water and pyrene from water-micellar surfactant media of various types, so it can be a promising matrix for SSF of pyrene and trypaflavine and their chemical analogs. The Coulomb interactions were proposed to determine eosin Y and trypaflavine concentration on the surface of CTS matrices and the SSF of these probes. The CTS fibers were permeable to hydrophobic pyrene dissolved in an ethanol-water medium or solubilized in the micelles of ionic surfactants.

Cellulose diacetate reinforced with electrospun cellulose fiber: A new route to prepare an all cellulose-based composite

An all cellulose-based composite was produced by applying cellulose diacetate (CDA) and electrospun cellulose fibers (ECFs) as a matrix and reinforcing fibers, respectively. The ECFs were prepared by electrospinning CDA followed by alkali treatment. The alkali treatment of the electrospun CDA fibers removes acetyl groups and creates new crystalline domains similar to cellulose fibers, which may result in increased mechanical properties. The physical properties of ECFs are highly correlated with the acetyl content. The mechanical properties of the CDA/ECF composites were evaluated by measuring the tensile strength and Young’s modulus as a function of the hydrolysis time. The results showed that the integration of the CDA matrix with 15% weight/weight (w/w) ECF7, which was alkali-treated for 7h, was optimal, resulting in an improved tensile strength and Young’s modulus by factors of 1.7 and 2.2, respectively. This study demonstrates that the increased mechanical properties are attributed to the reinforcement of ECFs as well as good interfacial adhesion.

Encapsulation of T4 bacteriophage in electrospun poly(ethylene oxide)/cellulose diacetate fibers

Phage therapy is a potentially beneficial approach to food preservation and storage. Sustained delivery of bacteriophage can prevent bacterial growth on contaminated food surfaces. Using coaxial electrospinning bacteriophage can be encapsulated in electrospun fibers with high viability. The resulting bio-based electrospun fibers may have potential as a food packaging material. In the present work, T4 bacteriophage (T4 phage) was incorporated into core/shell electrospun fibers made from poly(ethylene oxide) (PEO), cellulose diacetate (CDA), and their blends. Fibers prepared using PEO as the shell polymer showed an immediate burst release of T4 phage upon submersion in buffer. The blending of CDA with PEO significantly decreased the rate of phage release, with no released T4 phage being detected from the solely CDA fibers. Increasing the PEO molecular weight increased the electrospun fiber diameter and viscosity of the releasing medium, which resulted in a relatively slower T4 phage release profile. SEM analyses of the electrospun fiber morphologies were in good agreement with the T4 phage release profiles. Depending on the PEO/CDA ratio, the post-release electrospun fiber morphologies varied from discontinuous fibers to minimally swollen fibers. From these results it is suggested that the T4 phage release mechanism is through solvent activation/polymer dissolution in the case of the PEO fibers and/or by diffusion control from the PEO/CDA blend fibers.

Aryl Azide-Based Photografting of β-Cyclodextrin onto Cellulose Diacetate Fibers

In this work, cellulose diacetate (CDA) fibers, a derivative of cellulose, were modified with cyclodextrins by the photografting method. The CDA fibers have mainly been used as a cigarette filter due to their properties of the absorption and removal of low levels of certain organic chemicals.

Study of polymer dissolution and diffusion by laser interferometry

A Mickelson laser interferometer is used to study the polymer dissolution and diffusion in the system of cellulose diacetate fiber and nitromethane solvent. Digital interferograms at different stages of the diffusion mixing are obtained. The kinetics of the diffusion parameters (refractive index distribution and concentration of the medium) is considered. The diffusion coefficients of the polymer in the mass transfer process are determined, and their temperature dependences are constructed.

Novel regenerated cellulosic material prepared by an environmentally-friendly process

Novel regenerated cellulosic materials have been developed using an environmentally-friendly, facile process without releasing any toxic materials. Untreated, cellulose diacetate fibers were immersed in the aqueous caustic solution. The degummed and dried diacetate fibers were heated at a rate of 2 °C/min from 30 to 98 °C, then treated for 30 min at the same temperature and cooled at a rate of 2 °C/min to 30 °C, followed by the drainage of the liquid. The heat treated fibers were held under tension to prevent shrinkage during the thermal treatment. The materials possess excellent physical and dyeing properties, are pleasant to touch, and can be used in a variety of industrial fields. The microstructure of these materials is found to have a composite crystalline structure consisting of cellulose II and cellulose IV, exhibiting a lamellar morphology with an increased amorphous fraction, as compared to conventional rayon fibers, which is the main reason for their better elongation and solvent sorption ability.

Dyeing and fastness properties of vat dyes on a novel regenerated cellulosic fiber

enVix is a novel regenerated cellulosic fiber, which is prepared from cellulose diacetate fiber using environmentally friendly manufacturing process. Vat dyeing properties of the enVix were investigated and compared with those of regular viscose rayon. The enVix exhibited better dyeability than viscose rayon. The colour yields of vat dyes on the enVix were found to be dependent on dyeing temperature as well as the amount of levelling agent and salt. Good build-up and good to excellent fastness properties were obtained on the enVix fabric.

Study on Cellulosic Fiber Spun from its Lyotropic Mesophase Dope

An attempt was made to elucidate the effect of the total degree of substitution («F») and its distribution («fk», k =2, 3 and 6) of cellulose acetates (CA) in their lyotropic solution in common solvent (dimethvlacetamide; DMAc) on their molecular orientation behavior characterized by IR analysis, and to compare the properties of cellulose diacetate fibers spun from lyotropic solutions differing solvent (DMAc and aq-70 wt% nitric acid (HNO3)). The followings are found : 1) Molecular orientation phenomena of polymer and solvent for CD/DMAc lyotropic systems on imposing shear significantly differ depending on both (F) and (fk), for example, CA with higher «f6»/«F») tends to show similar molecular orientation to cellulose II even at almost same low (F). 2) The fibers spun from CDA/aq.70 wt% HNO3 lyotropic system exhibit always superior mechanical properties such as tensile strength and Younds' modulus to those of the fibers spun from CDA/DMAc lyotropic system. 3) The former lyotropic system shows a characteristic IR perpendicular dichroism band corresponding to ring CO stretching band which ordinary shows parallel dichroism for cellulose. 4) Kevlar-like structure is expected for the fibers spun from CDA/aq. 70 wt% HNO3 lyotropic system.

Photodegradation of cellulose acetate fibers

AbstractThe photodegradation of cellulose acetate fibers by ultraviolet light in vacuo at 77°K and at ambient temperature was studied. Three kinds of light sources with different wavelengths between 2353 and 6000 Å were employed. ESR studies at 77°K show that several kinds of free radicals are produced from cellulose diacetate (CDA) and cellulose triacetate (CTA) fibers when irradiated with light of wavelength shorter than 2800 Å. Among these methyl radicals formed decayed within 210 min at 77°K. When the temperature was raised above 77°K, radical transformation occurred at 87°K and most of the free radicals decayed at 193°K, whereas the cellulosic radicals were stable at this and even at higher temperatures. Ultraviolet spectroscopy studies revealed that the main chromophores are the carbonyl function of the acetyl group and acetal groups in the polymer. The photodegradation of the polymers at ambient temperature resulted in the formation of gaseous products (mainly CO, CO2, and CH4), together with the loss of bound acetic acid content and sample weight. Decreases in viscosity and reduction of tensile strength and elongation were also observed in the irradiated samples, revealing that the overt effects of ultraviolet light on cellulose acetate fibers are interpreted in terms of free‐radical reactions ultimately leading to main‐chain and side‐group scissions, unsaturation, and the formation of small molecule fragments. Among these, main‐chain scission took place predominantly in CDA fiber and side‐group scission in CTA fiber. The mechanism of the fundamental photochemical degradation processes of cellulose acetate fibers is elucidated.