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Hydrogel is considered as a promising candidate for bioink in terms of biocompatibility, biodegradability, printability and supporting cellular behavior. Recently, carbohydrates derivatives containing alkyne and azide pendant functional groups have been used in medical applications due to their improved chemical, biological, functional properties, and their amenability for chemical reactions under mild conditions. In this work, a novel bioink was developed based on azide and alkyne of cellulose derivatives. Azido-hydroxyethyl cellulose (D.Sazido = 0.04) was synthesized via open-ring reaction of 1-azido-2,3-epoxypropane and characterized spectroscopically and titrimetrically. Alkyne derivative, propargyl carboxymethyl cellulose (D.Spropargyl = 1.72) was synthesized through coupling reaction with propargylamine in the presence of EDC and NHS. The click-gel scaffold was obtained by mixing the two novel candidates in the presence of copper (I) catalyst. Extrusion bio-plotting experiment was successfully conducted of the two solutions into coagulant Cu (I)/DMSO solutions and demonstrated the possibility of using the clickable cellulose derivatives as bioink precursors. Chemical and physical properties of the click-gel were demonstrated. The biocompatibility assay of the prepared click-gels showed high level of viability in the human skin fibroblast cells (HFB4) at concentration 100 μg/mL.

Cellulose acetate (CA) electrospun fibers have been used in different medical applications such as drug delivery systems to release various drugs. CA, usually available with a typical degree of substitution (DS) of 2.4–2.5, shows little control over the release rate of the incorporated substances, due to the lack of active functional groups. In this work, click chemistry was used to activate CA and produce crosslinked electrospun mats to provide sustained release for topical administration. CA was activated by introducing azide functional groups on the residual hydroxyl groups of the polymer chains with a DSAzido of 0.24 by a coupling reaction. Azido-CA was then electrospun to produce nanofibers, in which capsaicin and sodium diclofenac, as pain-relieving drugs were encapsulated. Propargylated maltose was synthesized as a crosslinker to the Azido-CA via triazole chemistry. Spectral analysis was used to confirm the chemical structure of the new derivatives and the click-matrices. SEM morphological analysis of the Azido-CA electrospun fibers showed a range of diameters from 140 to 270 nm, with clear, smooth surfaces. Samples of the matrices were assessed for cytotoxicity and showed an acceptable cell viability. In a rat model, sodium diclofenac and capsaicin-loaded electrospun mats of Azido-CA showed superior closure rates over the untreated rats and those treated with a commercial cream. Rats treated with electrospun mat of CA, Azido-CA loaded with drugs showed normal intact histological structure of the epidermis and dermis.

Carbohydrates derivatives containing propargyl pending functional groups have been used in medical applications due to their improved chemical, biological, and functional properties. In this work, azide and alkyne pendant functional groups were introduced onto ethyl cellulose (EC) and β-cyclodextrin respectively in order to demonstrate the ability of scaffold formation by click chemistry. Technically, Azido-ethyl cellulose (D.S.Azido 0.19) and 2, 3, 6-O- propargylated β –cyclodextrin were synthesized and characterized as click-triggered candidates. The click-gel scaffold was obtained by mixing the two novel candidates in the presence of copper catalyst. Azido-EC was considered to produce clickable electrospun fibers blended with EC (290–620 nm) at 20 kV in order to functionalized EC substrate bearing azide groups to be amenable towards immobilization of an alkyne-terminated bio-molecules. The biocompatibility assay of the prepared click-triggered candidates showed very high level of viability in the human skin fibroblast cells (HFB4) at concentration 100 μg/ml.

Conjugated linoleic acids (CLA) as essential fatty acids (EFAs) have shown medical significance towards wound healing process. However, EFAs whose chemical structures possess unsaturated double bonds are unstable to environmental degradation. Encapsulation of EFAs into protective layer was the basic approach to avoid such degradation. In this work, CLA was extracted from sunflower oil, purified and characterized by spectral analysis. CLA was loaded into two different substrates namely hydrophobic, cellulose acetate (CA), and hydrophilic, liposomal emulsions of poly (vinylalcohol) (PVA) and gelatin, polymers. Electrospinning parameters were optimized to obtain clear, smooth and bead-free fibers. 12 % wt/v of CA shows bead-free fibers with diameter in range of 440-300 nm loaded with CLA up to 26% wt/wt. While, CLA (3% wt/wt) is encapsulated into the liposomal emulsions of PVA and gelatin with average fiber diameters 252-400 nm and 120-200 nm respectively. The CLA encapsulation, morphology of the electrospun fibers, and fiber diameter were examined using scanning electron microscopy (SEM). Viscosity and conductivity of the prepared solutions for electrospinning were demonstrated. Biocompatibility was evaluated by measuring cell proliferation of skin fibroblast cells. The release profile was investigated by UV- Visible spectroscopy. CLA loaded into the electrospun showed lower peroxide values (PV) of CLA.

This research aims to investigate the influence of soluble starch; lactose; carboxymethyl cellulose; urea; and polyvinylpyrrolidone on synthesis of zinc oxide nanoparticles (ZnO-NPs). Zinc acetate was used as a precursor under alkaline conditions to produce ZnO-NPs as a low-cost and efficient antimicrobial and UV-blocking agent. Characterization and antimicrobial functional properties of prepared nanoparticles were investigated and reported using FTIR, TGA, XRD, TEM, analysis, as well as antimicrobial assay, respectively. The results revealed that the thermal decomposition profile, size of ZnO-NPs, IR spectra, as well as antimicrobial activity of the prepared ZnO-NPs is governed by the type of capping agents. Crystallinity analysis showed identical patterns in peak intensities and width irrespective of the used capping agents. On the other hand, the obtained results disclosed that using soluble starch as a capping agent results in attaining lower particle size of 3–5 nm and higher antimicrobial efficacy as compared with the other capping agents.

a b s t r a c t A method to impregnate silver nanoparticles (AgNPs) into different polysaccharides substrates (cellulose powder (CP), microcrystalline cellulose (MCC), carboxymethyl cellulose (CMC) and chitosan (Chit)) by using glucose as reducing agent, is presented. X-ray diffraction analyses of polysaccharides coated with AgNPs showed the formation of silver particle sizes in the range of 3.7–5.6 nm and have almost spherical shape. The entire prepared composite shows antimicrobial effect. The antibacterial activity of polysaccharides loaded with silver nanoparticles was evaluated against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria. The results suggest excellent antibacterial activity.

Uncontrolled hemorrhage continues to be the leading cause of death from traumatic injuries both in the battlefield and in the civilian life. Chitosan is among the very few materials that have made the short list of military recommended field-deployable hemostatic dressings. However, the detailed mechanism of its action is still not fully understood. Moreover, in the cases when patients developed coagulopathy, the efficacy of the dressings rely solely on those mechanisms that work outside of the regular blood coagulation cascade. In addition to the well-known erythrocyte agglutination, we proposed to use the reactive N-iodoacetyl group on a new chitosan derivative to accelerate hemostasis. In this paper, we describe the synthesis of chitosan iodoacetamide (CI) with considerations of the stoichiometry among the reagents, the choice of solvent, the pH of the reaction medium, and the reaction time. The reaction was confirmed by FT-IR, 1H and 13C NMR, elemental analysis, iodine content analysis, and SEM-EDS. Water contact angle measurements and Erythrocyte Sedimentation Rate (ESR) method were used to evaluate the hemostatic potential of the newly synthesized CI as a function of their degree of substitution (DS). The range of DS was 5.9% to 27.8% for CI. The mid-range of DS gave the best results for the ESR. CIs exhibit favorable cytocompatibilities up to DS 18.7 compared to the generic unmodified chitosan. In general, the biocompatibility of chitosan iodoacetamide slightly declined with increasing the iodide content up to DS 21.5 owing to its affinity to SH groups of cells.

Cotton fabrics can be dyed with reactive and/or direct dyes in aqueous baths under certain specific conditions of pH, salt, temperature, time, etc., and rendered fire retardant through reaction with reactive phosphonopropionamide compounds. In the presence of reactive tertiary amines and reactive phosphorous derivatives, cotton fabrics can be dyed with reactive, direct or acid dyes in the absence of the usual added alkalis and salts, and in the mean time, the fabric becomes fire retardant with wash and wear properties. To verify such claims, reactive aminating agents are synthesized by reacting different amine compounds that have various numbers of amino groups with acryl amide and formaldehyde. The pad-dry-cure technique is applied to treated fabrics with aqueous finishing formulations that contain dyestuff and reactive amine-compounds; the cotton fabric will simultaneously impart reactive dyeing, easy-care inishing and fire-retardant properties. Systematic studies show that in the presence of 6% weight/weight, reactive amine in an aqueous formulation yields cotton fabric with the least loss in tensile strength and elongation at break, and an enhancement to the crease recovery angle. By adding the dyestuff to the aqueous formulation at fixed nitrogen content for treated cotton (0.2%) under identical dyeing conditions, the colour strength (K/S) increases for dyed cotton. The fastness properties of the dyed fabric are improved or remain unaltered for the three types of dyestuffs used

Modification of chitosan (CS) by means of blending with other polymers is a convenient method to improve its physical properties for practical utilization. The similarity of cellulose and chitosan in primary structures might facilitate the formation of homogeneous films. Mixing cyanoethylchitosan (CECS) with cellulose acetate (CA) overcomes mechanical weakness of CS films. CECS is prepared by reaction of chitosan with acrylonitrile in the vapour phase under a different reaction conditions, namely, sodium hydroxide concentration and reaction period. Blended films of CECS and CA are made by casting from dimethylformamide (DMF) followed by impregnation in water. CECS/CA films obtained are characterized by nitrogen content, tensile strength, elongation at break, FTIR and thermogravimetric analysis (TGA). Antibacterial activity of films prepared against Gram (−ve) and Gram (+ve) bacteria is measured via both disk diffusion method and bacterial count method. Blended films show good antibacterial effects toward Gram (+ve) bacteria than Gram (−ve) ones. Antibacterial activities of blended films increased by increasing the CECS percent in the blended films while the tenacity of these films gradually decreased. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) show that CECS possesses higher effect on Gram (+ve) bacteria Staphylococcus aureus than Gram (−ve) bacteria Escherichia coli. In the meantime, CECS is much more powerful in inhibition of bacteria than CS itself.

Reactive amine-amide derivatives are prepared via the addition reaction of different primary and secondary amines on acrylamide (AAm) using equivalent molar ratios and the resultant product is methylolated using equivalent amounts of HCHO. Bis (hydroxymethyl carbamoylethyl) ethylamine (I), tetra (hydroxymethyl carbamoyl ethyl) ethylene diamine (II) and penta (hydroxymethyl carbamoylethyl) diethylenetriamine (III) are prepared by reaction between ethylamine or ethylenediamine or diethylenetriamine and AAm. N-Hydroxydiethyl-phosphonopropianamide (IV) is prepared via Mecheal addition reaction of diethylphosphite with AAm followed by reaction with HCHO. To impact flame-retardancy and easy care finishing to cotton fabric aqueous formulations of compound IV, etherified methylolated melamine (EMM) and/or compounds III, II or I have been prepared. Cotton fabric treated by pad–dry–cure system, the drying time was investigated. Cured cotton fabrics are fire retardant if the aqueous formulation contains 12 % w/w of compound IV and 6 % w/w of EMM respectively. Physical and mechanical properties are less deteriorated when compound III, II or I are used instead of EMM and the liberated HCHO is almost decreased to one half by replacing EMM by one of the prepared methylol compounds. Treatments with compounds III, II or I is impart antibacterial and antifungus properties to the finished fabric.

A macromolecular sizing agent based on the copolymerization of poly(vinyl alcohol) (PVA) with hydrolysed starch was prepared using the chemically reactive bifunctional compound N-methylolacrylamide. Detailed characteristics of the resultant PVA/N-methylolcarbamoylethylated starch copolymer were studied where emphasis has been placed on solubility, rheological properties, molecular weight distribution, adhesive power and stability. Elucidation of the nature of the macromolecular segments of both N-methylolcarbamoylethylated PVA as well as PVA/N-methylolcarbamoylethylated starch copolymer fulfilled the prerequisite to tailor PVA/starch copolymer which is appropriate for application as a water-soluble recyclable sizing agent by ultrafiltration. Zur Entwicklung neuartiger okologisch vertraglicher makromolekularer Schlichtemittel wurden in fruheren Arbeiten Copolymerisationsreaktionen zwischen Polyvinylalkohol (PVA) und Starke unter Verwendung von chemisch reaktiven bifunktionellen Verbindungen wie N-Methylolacrylamid beschrieben. Im Rahmen dieser Arbeit werden die physikochemischen Eigenschaften des resultierenden Copolymeren untersucht. Von Bedeutung sind hierbei insbesondere Merkmale wie Molekulargewichtsverteilung, Klebekraft, Stabilitat, Loslichkeit sowie rheologische Eigenschaften. Derartige Kenntnisse uber die physikochemische Beschaffenheit der PVA-Ausgangsverbindung sowie des makromolekularen Endproduktes sind eine wesentliche Voraussetzung fur die Entwicklung von neuen Produkten, die als wasserlosliche, recycelbare Schlichtemittel zur Anwendung in der Textilindustrie kommen konnen.

Chitosan is a well known anti-microbial polymer. It is desired to develop and evaluate chitosan based structures with high surface area using electrospun nanofibers. To explore the properties of chitosan derivatives, iminochitosan was synthesized and electrospinning of its solutions was conducted. Nanofibers were obtained from iminochitosan solutions using trifluoroacetic acid (TFA) as a solvent. Nanofiberwebs of fiber diameter range 70–400 nm were successfully obtained from 3%-8% iminochitosan solution in TFA using electrospinning technique of electric field of 2.5–6.0 kV/cm. Contact kill performance of the iminochitosan structures against a range of microbes was carried out using the disc diffusion method. The results indicate that the nanofiberwebs exhibit excellent antimicrobial behavior. It was found that the inhibition zone is affected by the iminochitosan structure parameters, namely covering power, surface area (which was affected by diameter), and basis weight. Viscosity of the solutions was determined and fiber formation was obtained in the range of 400–670cP.

Changes in the physical as well as chemical structure of scoured and slack mercerized restretched (90–103% of original length) cotton yarns brought about by heat treatments and the effects of these on the strength properties of the cotton yarn were investigated. No striking changes in copper number, carboxyl content, iodine sorption, degree of polymerization (P) and strength properties were observed when the scoured and the mercerized yarns were heated at 160, 180, 200, and 210°C for up to 10 min. On the contrary, with the exception of carboxyl content, marked changes in these properties were determined when heat treatment was carried out for up to 96 h and 5 h at 160°C and 210°C, respectively. However, the mercerized yarns retained higher strengths in spite of higher degradation as compared to scoured yarn. The interrelationship between strength and P as well as strength and percentage of bonds broken together with measurements of frequency of successive regions of high lateral order indicated that mercerized cotton exhibited a more uniform structure which improved the distribution of stress along the fibre. Veranderungen der physikalischen und chemischen Struktur von entfetteten und merzerisierten verstreckten (90–103% der Originallange) Baumwollfaden durch Warmebehandlung und ihr Einflus auf die Festigkeitseigenschaften der Baumwollfaden wurden untersucht. Keine augenfalligen Veranderungen der Kupferzahl, des Carboxylgehalts, der Jodadsorption, des Polymerisationsgrades (P) und der Festigkeitseigenschaften wurden beobachtet, when entfettete und merzerisierte Faden bis zu 10 min auf 160, 180, 200 und 210°C erhitzt wurden. Im Gegensatz dazu wurden, mit Ausnahme des Carboxylgehalts, markante Veranderungen dieser Eigenschaften festgestellt, wenn die Warmebehandlung bis zu 96 h bei 160°C und 5 h bei 210°C durchgefuhrt wurde. Die merzerisierten Faden behielten jedoch eine hohere Festigkeit trotx starkeren Abbaus in Vergleich zu entfetten Faden. Die Beiziehungen zwischen Festigkeit und P sowie zwischen Festigkeit und Prozentsatz gespaltener Bindungen zusammen mit der Bestimmung der Haufigkeit aufeinanderfolgender Regionen hoher lateraler Ordnung zeigen, das merzeisierte Baumwoole eine einheitlichere Struktur hat, die eine bessere Verteilung von Spannungen entlang der Faser zulast.

The contribution of jute constituents, namely, water soluble matters, waxes, pectins, lignin, hemicelluloses, and α-cellulose in the graft copolymerization reaction of jute fabric with some vinyl monomers was investigated. Styrene, methylmethacrylate, and acrylonitrile were used as the monomers and Fe2+/H2O2 redox system as initiator. The graft copolymerization reaction was carried out at 80°C using different concentrations of monomer and initiator for different lengths of time. The water soluble matters, pectins, and lignin were found to accelerate the graft copolymerization reaction during the initial stages of the reaction and in the meantime impede termination during the latter stages of the reaction. Generally, the magnitude of grafting is governed by nature of the substrate, nature of the monomer, and the conditions of the polymerization reaction. Grafting decreases the moisture regain of jute and substrates derived thereof irrespective of the monomer used within the range studied. Also, grafting decreases the tensile strength and imparts rot-proofing properties to the substrates examined. Es wurde der Beitrag der Jutebestandteile, wie wasserlosliche Anteile, Wachse, Pektine, Lignin, Hemicellulosen und α-Cellulose auf die Pfropfcopolymerisation von Jutegewebe mit einigen Vinylmonomeren untersucht. Styrol, Methylmethacrylat und Acrylnitril wurden als Monomere verwendet und das Redoxsystem Fe2+/ H2O2 als Initiator. Die Propfcopolymerisation wurde bei 80°C mit unterschiedlichen Monomerund Initiatorkonzentrationen und Zeiten durchgefuhrt. Es zeigte sich, das die wasserloslichen Anteile, Pektine und Lignin die Pfropfcopolymerisation zu Beginn beschleunigen und wahrend der Endstufe der Reaktion den Abbruch behindern. Im Allgemeinen wird der Pfropfgrad durch die Natur des Substrates, des Monomeren und die Polymerisationsbedingungen gesteuert. Das Pfropfen erniedrigt die Feuchtigkeitsabgabe von Jute und daraus erhaltenen Substraten unabhangig von den Monomeren, die in der Untersuchungsreihe verwendet wurden. Ebenso erniedrigt das Pfropfen die Zugfestigkeit und macht die Substrate verrottungsfest.

Conditions were established to introduce almost equal and reproduciple amounts of diethylaminoethyl (DEAE) substituents into the molecular structure of scoured cotton (substrate I), slack mercerized cotton (substrate II), slack mercerized-stretched (94%, substrate III), and slack mercerized-stretched (103%, substrate IV) cotton. Similarities between the original structures of these substrates before and after the chemical modification were assessed by X-ray analysis. Comparison between the DEAE cottons and the corresponding unmodified cottons upon acid hydrolysis with respect to moisture regain, loss in weight and degree of polymerization was also made. Chemical analysis was used to study the compositions and structures of the hydrolyzates (i.e., hydrocelluloses and solublized fractions) resulting from hydrolysis of the modified cottons with 2.5 N HCl under reflux for different lengths of time. Studies of rates of hydrolysis of the cellulose, rates of removal of substituted glucoses and rates of removal of individual types of substituted glucose units were considered as means to provide information regarding: (a) distribution of DEAE substitutents throughout the structure of cellulose, (b) nature of accessible regions where the DEAE substituents are developed, and (c) selective availability of the hydroxyl groups at C-2, C-3 and C-6 of the D-glucopyranosyl units in the cellulose elementary fibril. Die Bedingungen, um nahezu gleiche Mengen von Diethylaminoethyl-Gruppen (DEAE) in die molekulare Struktur verschiedener Cellulosen (Substrate I bis IV) einzufuhren, wurden erprobt. Anderungen in der Morphologie, hervorgerufen durch die chemische Modifikation, wurden durch Rontgenanalyse ermittelt. Die Cellulosen wurden durch Saure hydrolysiert und die Hydrolysate eingehend chemisch untersucht. Aus den Hydrolysegeschwindigkeiten wurden Ruckschlusse auf die Verteilung der DEAE-Substituenten und die Zuganglichkeit der Hydroxylgruppen in den D-Glycopyranosyleinheiten der Cellulosefaserchen gezogen.

Fabric samples of polyester/cotton blend were graft copolymerized to different levels (add-ons) with poly(acrylic acid) and poly(methacrylic acid) using the mutual γ-irradiation technique and the Fe2+–H2O2 redox system, respectively. The copolymers so obtained were given durable press treatments with and without conventional nonionic softener using DMDEU as the crosslinking agent. The susceptibility of the copolymers before and after crosslinking to aqueous and nonaqueous oily soiling and their ability to release the soils were examined. It was found that hydrophilization of the surface of polyester/cotton blend through grafting with the said carboxyl-containing polymers brings about a significant improvement in the resistance of the blend to aqueous and nonaqueous oily soil particularly after crosslinking in presence of nonionic softener. A certain improvement in the ease of oily soil removal could be achieved by grafting. The opposite holds true for aqueous soil release. Soiling and soil release depends on the magnitude and method of grafting, medium of soiling, as well as the formulation of crosslinking treatments. The effect of grafting on some properties of the blend fabric before and after crosslinking was also examined.

(β-Alkoxypropionamide as well as hexahydro-1,3,5-x(β-alkoxypropionyl)-y(acryloyl)-s-triazine in nonaqueous medium were prepared. The products so obtained were reacted with cotton cellulose in nonaqueous medium under a variety of conditions. It was postulated that β-methoxypropionamide reacted with cotton cellulose in presence of an acid catalyst via a substitution reaction. Reaction of hexahydro-1,3,5-mono(β-alkoxypropionyl)-diacryloyl-s-triazine with cotton cellulose also proceeded mainly through a substitution reaction. Addition and/or polymerization reaction, which entailed saturation of the double bonds of the acryloyl groups, occurred when the chemical modification of cotton was carried out at high temperature (above 130°C) for more than 10 minutes using higher concentrations of hexahydro-1,3,5-mono(β-alkoxypropionyl)diacryloyl-s-triazine (8% or more)). β-Alkoxypropionamid sowie Hexahydro-1,3,5-x(β-alkoxypropionyl)-y(acryloyl)-s-triazin wurden in nichtwaβrigem Medium hergestellt. Die erhaltenen Verbindungen wurden mit Cellulose in nichtwaβrigem Medium unter verschiedenen Bedingungen umgesetzt. Es wurde angenommen, das β-Methoxypropionamid mit Cellulose in Gegenwart eines Saurekatalysators unter Substitution reagiert. Dieselbe Reaktion wurde auch fur Hexahydro-1,3,5-mono(β-alkoxypropionyl)-diacryloyl-s-triazin mit Cellulose angenommen. Eine Addition und/oder Polymerisation unter Absattigung der Doppelbindungen der Acryloylgruppen trat ein, wenn die chemische Cellulosemodifi-zierung oberhalb 130°C mehr als 10 Minuten lang mit Hexahydro-1,3,5-mono-(β-alkoxypropionyl)diacryloyl-s-tnazin hoerer Konzentration (8% oder mehr) ausgefuhrt wurde.

Grafting of styrene onto cellulose carbamate was investigated under a variety of conditions using H2O2 as initiator. The graft yield was found to depend on the amount of carbamate groups, initiator and monomer concentrations as well as on temperature and pH of polymerization. The graft yield increased with increasing H2O2 concentration, attained a maximum at a concentration of 0.18% then fell down sharply. Maximal grafting occurred at a monomer concentration of 6.6%. The graft yield increased also by raising the polymerization temperature up to 80°C, attained maximum at 90°C then decreased significantly. With respect to pH, the graft yield decreased markedly upon increasing the pH from 2 to 4 and marginally upon further increase in pH. Addition of FeSO4 to the polymerization system caused a considerable decrement in the graft yield. A comparison between the graft yield obtained with the modified cellulose having different amounts of carbamate groups with those of the unmodified cellulose indicated that cellulose carbamates having less than 1.1% nitrogen showed lower graft yields than the unmodified cellulose. Above this, cellulose carbamate was much more amenable to grafting than the unmodified cellulose. Die Pfropfung von Styrol auf Cellulosecarbamat wurde unter verschiedenen Bedingungen in Gegenwart von H2O2 als Initiator untersucht. Es wurde gefunden, das die Pfropf-Ausbeute von der Menge an Carbamatgruppen, Initiator und Monomeren ebenso wie von Temperatur und pH bei der Polymerisation abhangig ist. Die Pfropf-Ausbeute nahm mit steigender H2O2-Konzentration zu, erreichte ein Maximum bei 0.18% H2O2 und fiel dann plotzlich ab. Die maximale Pfropfung trat bei einer Monomerkonzentration von 6.6% ein. Die Pfropf-Ausbeute nahm auch bei Erhohung der Polymerisationstemperatur bis auf 90°C zu. Eine Erhohung des pH-Wertes von 2 auf 4 lies die Pfropfausbeute deutlich absinken. Auch der Zusatz von FeSo4 verursachte eine erhebliche Verringerung der Pfropf-Ausbeute. Ein Vergleich zeigt, das Cellulosecarbamat mit weniger als 1.1% Stickstoffgehalt eine niedrigere Pfropf-Ausbeute als nicht modifizierte Cellulose ergibt. Oberhalb dieses Stickstoffgehalts last sich Cellulosecarbamat besser pfropfen als die nicht modifizierte Cellulose.

Polymerization of glycidyl methacrylate (GMA), methacrylic acid (MAA), acrylamide (Aam) and their binary mixtures with cotton cellulose fabrics using Fe2+-thioureadioxide-H2O2 redox system was investigated under a variety of conditions. While temperatures of 50, 80, 65, and 95°C constituted the optimal polymerization temperature for GMA, MAA, Aam and GMA/MAA (8:2), respectively, maximum polymerization of GMA/MAA (2:8), Aam/MAA (8:2) and Aam/MAA (2:8) occurred at 75°C. The polymerization reaction proceeded initially very fast then levelled off irrespective of the monomer or monomer mixtures used. However, the magnitude of the polymer add-on at levelling off of polymerization followed the order GMA > GMA/MAA (2:8) ≥ GMA/MAA (8:2) > Aam/MAA (2:8) ≥ MAA ≥ Aam/MAA (8:2) > Aam. The polymer add-on enhanced by increasing the H2O2 concentration up to a certain limit and then decreased. The same situation was encountered with respect to thioureadioxide concentration. The involvement of the epoxy ring of GMA with MAA during polymerization of their mixture with cellulose occurred only at a higher ratio of GMA in the mixture. Also a significant contribution of Aam in the polymer add-on obtained with a Aam/MAA mixture could only be achieved at a higher ratio of Aam in this mixture. Die Polymerisation von Glycidylmethacrylat (GMA), Methacrylsaure (MAA), Acrylamid (Aam) und ihrer binaren Mischungen wurde mit Baumwolle-Cellulose-Geweben unter verschiedenen Bedingungen mit einem Fe2+-Thioharnstoffdioxid-H2O2-Redox-System untersucht. Die optimalen Polymerisationstemperaturen fur GMA, MAA, Aam und GMA/MAA (8:2) lagen bei 50, 80, 65 bzw. 95°C, fur GMA/MAA (2:8), Aam/MAA (8:2) und Aam/MAA (2:8) bei 75°C. Die Polymerisation war am Anfang sehr schnell, spater wurde sie langsamer, unabhangig vom Monomeren oder der Monomermischung. Die Pfropfausbeute nach der Verlangsamung der Polymerisation folgte der Reihe GMA > GMA/MAA (2 : 8) ≥ GMA/MAA (8 : 2) > Aam / MAA (2 : 8) ≥ MAA ≥ Aam/MAA (8 : 2) > Aam. Die Pfropfausbeute stieg mit steigender H2O2-Konzentration bis zu einem bestimmten Punkt, dann wurde sie wieder geringer. Dasselbe geschah bei steigender Thioharnstoffdioxid-Konzentration. Der Epoxy-Ring von GMA reagierte mit MAA wahrend der Polymerisation der Mischung mit Cellulose nur bei einem hoheren GMA-Verhaltnis in der Mischung. Ebenso konnte ein wesentlicher Beitrag von Aam auf das Aufgepfropfte in einer Aam/MAA-Mischung nur bei einem haheren Aam-Verhatnis in der Mischung erreicht werden.

Treatment of cotton fabrics with alkaline aqueous solutions of hexahydro-1,3,5-triacryloyl-s-triazine (I) under different reaction conditions leads to fabrics containing varying numbers of double bonds as reactive centers. A similar result is also obtained when the fabrics are treated with a mixture of acrylamide (II), N-hydroxymethylacrylamide (III), and N,N'-methylene-bis-acrylamide (IV). Experiments indicate that in all cases the presence of the double bonds in the fabrics can be attributed to the deposition of insoluble polymeric products. However, when the fabrics were treated with I in a mixture of alcohol and chloroform in presence of triethylamine, a true chemical reaction between I and cellulose could be effected to give cotton with reactive double bonds. The reaction of cotton with II, III, and IV in alkaline medium is also investigated in detail.

Reaction of cellulose carbamate with p-nitroaniline seems to occur via direct condensation of the amino group of p- nitroaniline with the carbamate groups of cellulose carbamzte. This reaction was effected by using three techniques: viz. a) padding cellulose carbamate in p-nitroaniline dissolved in acetone, drying, and baking at 180°C; b) padding cotton cellulose in aqueous urea solution, drying, then padding in p-nitroaniline solution, drying, and baking; and c) padding cotton cellulose in a solution containing urea together with p-nitroaniline in water/acetone mixture, drying, then baking. The extents of reaction for the three techniques were identical, provided that factors governing the extent of reaction were kept identical. These factors were urea and p-nitroaniline concentrations, temperature, and time of baking. The reaction product of cellulose carbamate with p-nitroaniline could be used to bring about a set of different colors by sub jecting it to reduction, diazotization, and coupling with different coupling agents. Trials to replace p-nitroaniline with o-nitroanHine and aniline were also made.

Fe2+-thioureadioxide-H2O2-redox system induced polymerization of various vinyl monomers with flax, alkali-treated flax, and partially carboxymethylated flax was investigated. Monomers used included glycidyl methacrylate (GMA), methyl methacrylate (MMA), 2-hydroxy ethylmethacrylate (2-HEMA), and acrylonitrile (AN). The polymerization reaction was carried out under a wide range of conditions including temperature (50–90°C), H2O2 concentration (0.01–1%), monomer concentration (20–200%, based on sample weight), and time (5–120 min). Results obtained led to the following conclusions: Raising the polymerization temperature from 50 to 60°C increases the percent polymer add-on while the latter decreases by further increase in temperature, irrespective of the substrate and monomer used. The percent polymer add-on increases by increasing monomer concentration from 20 to 200% and by increasing H2O2 concentration up to 0.1%, then decreases upon using higher H2O2 concentrations due to faster rate of termination. For a given polymerization condition, the percent polymer add-on follows the order partially carboxymethylated flax > alkali treated flax > flax. Monomer reactivity follows the order: GMA > 2-HEMA > MMA > AN. Poly(GMA)-containing flax retains its free epoxy rings practically intact, provided that the add-on is low (ca. 10%). Involvement of these functional groups in reactions with the functional groups of flax occurs at higher percent add-on (ca. 50–100%). Die mit dem Redox-System aus Thioharnstoffdioxid, H2O2 und Fe2+ ausgeloste Propfcopolymerisation auf Flachs, alkalibehandelten Flachs und teilweise carboxymethylierten Flachs wurde untersucht. Die dazu verwendeten Monomeren waren Glycidylmethacrylat (GMA), Methylmethacrylat (MMA), 2-Hydroxyethylmethacrylat (2-HEMA) und Acrylnitril (AN). Die Polymerisationen wurden unter verschiedenen Bedingungen durchgefuhrt (Temperatur: 50–90°C; H2O2-Konzentration: 0,01–1%; Monomerkonzentration: 20–200%, -bezogen auf die Substrateinwaage; Reaktionszeit: 5–120 min). Bei Temperaturerhohung von 50 auf 60°C nimmt die Pfropfausbeute zu, bei hoherer Temperatur wieder ab. Mit steigender Monomerkonzentration nimmt die Pfropfausbeute zu, ebenfalls mit zunehmender H2O2-Konzentration bis 0,1%, bei hoherer Konzentration an H2O2 wieder ab. Bei gegebenen Reaktionsbedingungen ergibt sich fur die Pfropfausbeute fur die verschiedenen Substrate folgende Reihenfolge: carboxymethylierter Flachs > alkalibehandelter Flachs > Flachs. Die Monomerreaktivitat folgt der Reihe: GMA > 2-HEMA > MMA > AN. Die mit GMA angepfropften Epoxid-Gruppen bleiben bei kleinem Pfropfungsgrad (ca. 10%) erhalten, bei hoherem Pfropfungsgrad gehen sie zunehmend Reaktionen mit den funktionellen Gruppen des Flachses ein.

Scoured ply cotton yarn (substrate I) was slack mercerized (substrate II) and slack mercerized followed by stretching to 94% (substrate III) and 103% of original length (substrate IV). These substrates were given an acid pretreatment (0.5 N HCl, 60°C, 15 min). The four substrates and their corresponding HCl-treated substrates (substrates I-H, II-H, III-H and IV-H) were reacted under similar conditions with N,N-diethylaziridinium chloride to yield diethylaminoethyl (DEAE)-cottons. In addition, DEAE-cottons of substrates I, I-H, II and II-H were hydrolyzed with 0.5 N HCl at 80°C for 0.5, 1, 2, 3, 5 and 7 h and the ratio of substituents in the D-glucopyranosyl units of these DEAE-cottons as well as in those of DEAE-hydrocelluloses were determined. It was found that there is a considerable difference between the reactivity of scoured cotton and slack mercerized-restretched cottons. This was interpreted in terms of differences in the microstructure between the substrates in question, which in turn, are reflected on availability, accessibility and state of order of the cellulose hydroxyls in the scoured and mercerized cottons. Nitrogen-, chemical, microscopical and X-ray analyses were used to assess the structural differences among the substrates. Gebeiztes Baumwollgarn (Substrat I) wurde spannungslos mercerisiert (Substrat II) und spannungslos mercerisiert, dann verstreckt um 94% (Substrat III) und 103% der urspriinglichen Lange (Substrat IV). Diese Substrate wurden einer Saurevorbehandlung unterworfen (0,5 N HCl, 60°C, 15 min). Die vier Substrate und ihre entsprechenden HCl-behandelten Substrate (I-H, II-H, III-H und IV-H) wurden unter ahnlichen Bedingungen mit N,N-Diethylaziridinchlorid umgesetzt, um Diethylaminoethyl (DEB)-Baumwolle zu erhalten. Zusatzlich wurden DEAE-Baumwollproben der Substrate I, I-H, II und II-H mit 0,5 N HCl bei 80°C 0,5, 1,2,3,5 und 7 h hydrolysiert und das Verhaltnis der Substituenten in den D-Glucopyranosyl-Einheiten dieser DEAE-Baumwollproben sowie in denen der DEAE-Hydrocellulosen wurde bestimmt. Es wurde gefunden, das ein beachtlicher Unterschied zwischen der Reaktivitat gebeizter und spannungslos mercerisierter nachverstreckter Baumwolle besteht. Dies wurde im Sinne von Unterschieden in der Mikrostruktur der verschiedenen Substrate interpretiert, die umgekehrt Verfugbarkeit, Zuganglichkeit und Ordnungszustand der Cellulose-Hydroxylgruppen in gebeizter und mercerisierter Baumwolle widerspiegeln. Stickstoff-, chemische, mikroskopische und Rontgenanalysen wurden benutzt, um die strukturellen Unterschiede zwischen den Substraten festzustellen.

Flax fibres containing different amounts of non-cellulosic constituents were prepared by subjecting the fibres to scouring and/or bleaching under different conditions. Scouring was based on treatment with an aqueous solution of either alkaline sulphite or alkaline dithionite followed by bleaching with an aqueous sodium chlorite/potassium permanganate system. The scoured flax fibres exhibited much greater bleaching effect than did the grey flax. Grey flax and the four bleached substrates were reacted with urea to yield flax carbamate. This was methylolated by reaction with formaldehyde. The extent of carbamation was related to the amount of the non-cellulosic material in the substrate and the presence of copper(II) chloride. The dyeability of the bleached flax was increased by the carbamation and methylolation sequence. The colour strength of dyed fibres was influenced by the methylol group content of the modified flax, the dyebath pH and nature of the dye used.

Carboxymethylation of flax has been carried out by first treating the fibres with sodium hydroxide followed by the sodium salt of monochloroacetic acid. The treatment was carried out under a variety of conditions. Variables studied included concentrations of monochloroacetic acid and sodium hydroxide in the impregnating solutions, as well as duration and temperature of the reaction. it was found that the extent of carboxymethylation increased substantially by controlling the concentrations of alkali and monochioroacetic acid, and by reacting for 6d min at 70dC. The behaviour of selected samples of partially carboxymthylated flax towards basic dyes was also studied.

Scoured ply cotton yarn was slack mercerized followed by restretching the cotton yarn to 90–103% of the original length in the mercerizing solution. The scoured and the mercerized cotton yarns were subjected to weathering for up to 14 months. Regardless of the cotton substrates, exposure to weathering was accompanied by an increase in copper number, decrease in both degree of polymerization (DP) and iodine sorption, and a loss in strength properties. No significant change in the carboxyl content of scoured and mercerized cottons could be observed after weathering. However, mercerized cottons retained higher strength in spite of higher degradation as compared to scoured cotton. This was interpreted in terms of removal of structural imperfections or weak links in cotton during the combined as swelling and stretching process evidenced by interrelationships between tenacity and percentage of bonds broken, as well as tensile strength and DP together with measurement of the average distances between crystallite centers in scoured and mercerized degraded cotton.