Modified Cellulose Fibers Research Articles

A novel synthesis of 1‐oxo‐thieno[3’,2’‐3,4] pyrazolo[1,2‐a] pyrazole azo dye systems for dyeing of synthetic and modified cellulose fibers

A new series of the title pyrazole azo dye systems has been synthesized. The new dyes are applied on nylon and cellulose acetate fibers to give dyed fabrics with excellent properties of colour intensity and fastness properties. The physical and spectral data of the investigated dyes are illustrated. The shifts of ultraviolet‐visible absorption maxima affected by the structural configuration of the pyrazole dye systems are investigated. The structural effects of the polyfunctionally substituted pyrazole dye systems on the intensity of colour and fastness properties of the dyed fabrics are discussed. The data of these studies are listed. The colour shades of the synthesized dyes on nylon and acetate fabrics are indicated.

Synthesis of a new series of polyfunctionally substituted pyrazole azo dye systems for dyeing of synthetic and modified cellulose fibers

Three series of azo dye systems are considered, namely, 5‐oxo‐2‐pyrazoline azo dye systems 9 a‐d,1‐oxo‐pyrazolo pyrazole azo dye systems 10 a, b, c, e, 11 a, b, c, e, 12 a, b, c, e, 13 a‐d and 6‐oxo‐pyranopyrzole azo dye systems 14 a‐d. The shifts of ultraviolet‐visible absorption maxima affected by the structural configuration of the pyrazole dye systems are investigated. The structural effects of the polyfunctionally substituted pyrazole dye systems on the intensity of colour and fastness properties of the dyed fabrics are also discussed. The data of these studies are listed. Colour shades of the synthesized dyes on nylon and acetate fabrics are indicated.

Determination of polarity parameters of chemically modified cellulose fibers by means of the solvatochromic technique

The surface polarity of organically functionalized cellulose fibers has been characterized with linear solvation energy relationships. The Kamlet–Taft hydrogen-bond-donating ability, the hydrogen-bond-accepting ability, the dipolarity/polarizability, Gutman's acceptor number (an indicator of the electron-accepting ability), and Reichardt's ET (30) parameter have all been used to quantitatively represent the polarity of the chemically treated and untreated fiber surfaces. Three different probe dyes, cis-dicyanobis(1,10-phenanthroline)-iron(II), Michler's ketone, and aminobenzodifuranone, have been used as indicators to measure the polarity with correlation analysis of the energy of the ultraviolet–visible absorption maxima. Solvatochromic methods have been proven to be effective in characterizing chemically modified lignocellulosic fibers. Different silanes, NaOH, and long alkyl groups, used to modify the cellulose fiber surface, have changed the hydrogen-bond-donating ability of the fiber. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2546–2553, 2000

Aluminum Oxide Coated Cellulose Fibers Modified withn-Propylpyridinium Chloride Silsesquioxane Polymer: Preparation, Characterization, and Adsorption of Some Metal Halides from Ethanol Solution

Aluminum oxide coated cellulose fibers were modified, by an impregnation procedure, withn-propylpyridinium chloride silsesquioxane polymer. Good adherence of the polymer to the surface of modified cellulose fibers was obtained due to the Al–O–Si bond formation. The metal X-ray mapping showed that aluminum oxide and the silsequioxane polymer (Al and Si mapping) are highly dispersed on the fiber's surface. The ion exchange capacity of the material, determined on basis of exchangeable chloride ions, was 1.1 mmol g−1. The adsorption isotherms of FeCl3, CuCl2, and ZnCl2from ethanol solutions were determined for each metal. The adsorption capacities were (in mmol g−1): FeCl3= 0.82, CuCl2∼ ZnCl2= 0.37. The metal ions are adsorbed as anionic complex species by the following equilibrium reaction: [graphic] + MCln⇄ [graphic

Asbestos on textiles: is there an endangering during washing and wearing?

Asbestos is a ubiquitous environmental pollutant despite the ban of its use since about 10 years ago. Textiles may be contaminated by asbestos fibres from drinking water or household chemicals, and so a health risk could be possible. To obtain knowledge on the real hazard of asbestos fibres deposited on textiles, the behaviour of asbestos during washing, rinsing and drying of textiles has been investigated using an asbestos-like model fibre, i.e. fluff of cationically modified cellulose fibres. The results showed only small amounts of about 10% of contaminating fibres remained after washing and drying. Some special investigations were also made using asbestos fibres themselves. The simultaneous influence of mechanical and thermal energy, increased by addition of detergents leads to a continuous fibrillation of the asbestos fibres reducing their length below that believed to be hazardous to health. The results cannot be transferred to highly contaminated protective clothing without additional investigations. However asbestos contamination of textile from drinking water or household chemicals in washing processes is highly unlikely to give rise to a health hazard.

Recent advances in the elaboration of polymeric materials derived from biomass components

This paper outlines a selected number of topics related to ongoing research activities of our laboratory in the field of polymers from renewable resources. Firstly, the use of polysaccharides is discussed both in the context of film-forming polymer electrolytes and of surface chemical modification of cellulosic fibres. The second aspect concerns the synthesis of polyesters and polyurethanes based on lignins of various origins. A large section is then devoted to novel furanic polymers and oligomers possessing special properties, and to the application of the Diels–Alder reaction to modify reversibly the architecture of macromolecules bearing furan rings. Finally, the use of modified vegetable oils as diluents in printing ink formulations and the investigation of the composition and possible exploitation of suberin are briefly discussed. © 1998 Society of Chemical Industry

The chemical modification of cellulosic fibres to enhance dyeability

The chemical modification of cellulosic fibres to enhance dyeability

The surface chemical modification of cellulosic fibres in view of their use in composite materials

The surface modification of various cellulosic materials was studied in heterogeneous conditions using different grafting agents bearing anhydride or isocyanate reactive groups. Some of these reagents were oligomeric, others polymeric and most were chosen so as to provide a non-polar character to the surface of the fibres in view of their possible use as reinforcing agents in composites based on polymeric matrices. The success of these chemical modifications was assessed by Fourier-transform Infrared Spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and elemental analysis. The accessibility of the superficial OH groups varied as a function of the coupling agent in terms of both molecular size and chemical nature and ranged between 1 and 3% of the total hydroxy groups borne by the initial cellulose sample.

Plasma modification of cellulose fibers: Effects on some polymer composite properties

AbstractCellulose fibers have been surface‐modified by selected cold, microwave plasma treatments. Inverse gas chromatographic (IGC), XPS, and SEM analyses showed surface treatment to be incomplete, but, nevertheless, effective in controllably altering the acid/base interaction balance of fiber surfaces. Surface‐modified fibers were used in composites with polystyrene (PS), chlorinated polyethylene (CPE), and polypropylene (PP) as, respectively, basic, acidic, and neutral matrices. Favorable acid/base interactions led to enhanced mechanical properties and increased glass transition temperatures of composites. Acid/base interaction appears to be an important, though not the sole consideration, in the design of superior systems using cellulose fibers as reinforcing agents. As expected, in the case of PP composites, acid/base considerations proved to be irrelevant. © 1994 John Wiley & Sons, Inc.

繊維の化学改質により得られる機能紙

In recent years, the importance of cellulosic materials as a renewable resource has increased because of environmental problems of petroleum-based plastics. Since there are three hydroxyl groups on each anhydroglucose ring of the cellulose, we can get various functional materials using chemical modifications. However, most of functional papers (or high performance papers) are given by the treatment of coating, laminating, blending or addition of chemicals. Thus, functional papers given by chemical modification of cellulose fiber are comparatively few. In this paper, properties and prospects of some functional papers derived from modified cellulose fibers were discussed.Since acetyl cellulose can be prepared untoxically and has interest characteristics, it is expectable as a clean substrate for functional papers. Cyanoethyl cellulose has some available electrical properties, and can be used for a base material for further functional papers. Aminated and carboxylated cellulose sheets were useful as ionic materials.As an example of functional use of chemically modified fibers, water-resistant paper given by N-chlorinated carbamoylethyl cellulose pulp was presented. Handsheets obtained from this pulp had excellent wet-and dry-strength properties.

Effect of structural modification of cellulose fibres on their sorption properties

Sorption of water vapors, hydroxide ions, iodine, and dyes by native and modified cellulose fibres with a different degree of crystallinity was investigated. Linear correlations were established between sorption of these substances and the concentration of noncrystalline regions in the cellulose. Equations were proposed for determining the degree of crystallinity of cellulose materials by sorption methods.

The nature of adhesion in composites of modified cellulose fibers and polypropylene

AbstractCellulose fibers were surface modified with polypropylene–maleic anhydride copolymer. The physical properties of such fibers were characterized by contact angle measurements, and the chemical structure was identified with ESCA and FTIR. ESCA showed that the modifying agent was localized at the surface of the fibers. The modified fibers were compounded with polypropylene, and composites with various amount of fibers were manufactured by injection molding. All mechanical properties were improved when treated fibers were used. SEM showed improved dispersion, wetting of fibers, and adhesion. The nature of adhesion was studied using FTIR. It was found that the surface modifying agent is covalently bonded to the fibers through esterification. The degree of esterification is enhanced by activating the modifying agent before fiber treatment. This study has shown the effects of treatment conditions on activation of reactive species and chemical reaction between fiber and modifying agent. Moreover, a better understanding has been achieved of the nature of adhesion for the system.

Chemically and physically crosslinked porous gels

AbstractChemically crosslinked gels made by polymerization and copolymerization of trimethylolpropane trimethacrylate have been characterized. Bimodal pore size distributions were obtained. The radii of the large pores (100 Å to 1 μm) varied with concentration while the small ones (20 to 30 Å) were largely independent of the concentration of TRIM. A mechanism of formation of the pores is outlined.Physically crosslinked gels of polyacrylonitrile with highly porous structures were made by cooling polymer solutions in DMF containing varying amounts of water. By controlling the thermal treatment the pore sizes could be varied from 0.1 to 1 μm.Finally the surface modification of cellulose fibers with derivatives of dichlorotriazine is described. It is shown that derivatives containing double bonds in the side chain can form covalent bonds across the interface between cellulose and an unsaturated polyester.

Surface modification of cellulose fibers III. Durability of cellulose–polyester composites under environmental aging

AbstractThe effects of improved interfacial adhesion on the environmental aging behavior of cellulose–polyester composites were studied. The reduction in maximum water content of the composites upon immersion in water which occurs for surface‐treated fibers is explained by the restrictions from fiber/matrix network. Whitening of the specimens based on the untreated fibers, or on fibers treated but not covalently bonded to the matrix, was found to be due to the formation of debonding cracks. Such cracks were formed on drying the materials. When the fiber and the matrix are covalently bonded, the matrix follows the fiber during shrinking, and thus no cracks are formed.

Surface modification of cellulose fibers. II. The effect of cellulose fiber treatment on the performance of cellulose–polyester composites

AbstractCellulose fibers treated with different coupling agents based on trichloro‐s‐triazine have been evaluated in terms of their reinforcement effect on unsaturated polyesters. The treatment with coupling agents containing double bonds resulted in what we believe to be the formation of covalent bonds between fiber and matrix. This has been compared with a treatment, which can only lead to formation of close interfacial molecular contact by wetting. The tensile properties of composites prepared from treated and untreated fibers were studied before and after exposure to water. It was found that all types of fiber treatment decreased water absorption and the reduction of mechanical properties in wet conditions, but that the degradation at the fiber/matrix interface which occurs from immersion in water and drying could only be avoided through the development of covalent bonds between fiber and matrix. Scanning electron microscopy was used to study the adhesion between fiber and matrix. An explanation of the reduction of mechanical properties of cellulose‐fiber reinforced polymers in wet conditions is proposed.

Surface modification of cellulose fibers. I. Spectroscopic characterization of surface‐modified cellulose fibers and their copolymerization with styrene

AbstractTwo coupling agents based on trichloro‐s‐triazine with different terminal unsaturated groups were synthesized in order to improve the bonding between cellulose fibers and an unsaturated polyester matrix. The products of the reactions between hydroxyl groups of cellulose and reactive species of coupling agents were analysed by Fourier‐transform infrared spectroscopy (FTIR) and by elemental microanalyses. ESCA was used for surface characterization of treated fibers. The coupling agents were found to be concentrated on the fiber surface. Polymerization of styrene was carried out in the presence of treated fibers. That the unsaturated groups of the treated fibers were able to copolymrize with styrene was shown by FTIR. Further evidence of the presence of grafted polystyrene on the surfaces of the cellulose fibers was provided by ESCA measurements.

Temperature dependence of the brittleness of cellulose fibers and of chemically modified cellulose fibers

AbstractThe temperature dependence of the brittleness of cellulose fibers was studied by the breaking twist angle method. The selected fibers were purified ramie cells, the same cells after fibrous acetylation to form the triacetate, annealed acetylated ramie cells, and mercerized ramie cells. Water acts as a plasticizer to reduce the brittleness of ramie and of mercerized ramie cells but does not appear to affect the brittleness of ramie cells after acetylation. The brittleness of ramie cells is reduced by similar amounts by fibrous acetylation and by mercerization. The brittleness of acetylated ramie cells is increased by annealing, which induces additional crystallization in the cells. The brittleness of ramie and acetylated ramie before and after annealing varied as the test temperature was progressively increased in the range 100–200°C. The effect of temperature on the brittleness of the fibers is interpreted in terms of the relaxation transitions previously determined on the same types of fibers, and in terms of the supramolecular structure of the fibers.

X‐Ray diffraction and iodine adsorption of acid modified cellulose fibers

AbstractThe crystallinity of acid modified fibers prepared from viscose rayon and cotton cellulose is determined by x‐ray diffraction and iodine adsorption methods. The results are analysed and interpreted in the light of the definition of each method. In addition, the role of low fractions as well as the effect of vacuum drying on the measured crystallinity are discussed. The literature shows a lack of consistency between crystallinity determined for cellulosic fobers using different methods. The present work is an attempt to analyse the crystallinities of hydrocellulose residues determined by the x‐ray diffraction and the iodine adsorption methods.

X-Ray Investigations on Celluloses Grafted by the Thiocarbonation Method

Abstract It is a pleasure for me to contribute to the symposium held in honor of my colleague and old friend Vivian Stannett. The topic of this contribution is results of x-ray investigations on graft modified cellulose fibers.