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1.
This study deals with the grafting of carbohydrate monomers on poly(ethylene terephthalate) fibers by double argon plasma treatment. Two monomers were used: allyl alpha-D-galactopyranoside and 2-methacryloxyethyl glucoside. The quantity of grafted carbohydrates was determined by phenol/sulfuric acid colorimetric titration. The graft density was observed to vary according to the monomer used. Allyl alpha-D-galactopyranoside yields to smaller graft densities compared to 2-methacryloxyethyl glucoside, suggesting transfer reactions occurring at the surface with allyl alpha-D-galactopyranoside. Fibers with the highest graft levels were obtained with the higher monomer concentration and the lower quantity of fiber treated in a plasma reactor. The grafting density can be modulated by the monomer concentration and mass of fiber exposed in the plasma reactor. For 0.5 mg of fibers, the graft densities for 23 and 68 mM allyl alpha-D-galactopyranoside are, respectively, 18 and 35 nmol/cm2. For 0.5 mg of fibers, the graft densities for 19 and 38 mM 2-methacryloxyethyl glucoside are, respectively, 150 and 250 nmol/cm2. Comparative study without the preactivation treatment shows the efficiency of the preactivation: for a mass of fiber of 0.5 mg and a 2-methacryloxyethyl glucoside concentration of 38 mM, the grafting density without plasma pretreatment is 38 nmol/cm2. Attenuated total reflectance Fourier transform infrared spectra confirmed the anchoring of the glycopolymer onto the poly(ethylene terephthalate) surfaces. Atomic force microscopy and scanning electronic microscopy pictures indicated their morphological changes.  相似文献   

2.
In recent years, the textile industry must go towards sustainable technologies and developing environmentally safer methods for textiles processing. One way is the processing with enzymatic system, rather than conventional chemical methods. The aim of this work was to investigate the changes induced on nylon 6,6 fiber by enzymatic system using different proteolytic enzymes. Technical measurements were studied including Fourier-transform infrared spectroscopy, scanning electron microscopy, thermal, dyeability, and fastness properties. For this purpose, nylon 6,6 fabrics were first treated separately with different concentrations of four protease enzymes. The dyeing process was then carried out on the treated fabrics with two reactive and acid dyes. The intensity of major peaks in FTIR spectra of the protease treated samples is in favor of chemical changes of the polypeptide functional groups in fabric. Thermal studies also show significant decrease in thermal degradation temperature of the treated polymer. Reactive and acid dyes showed higher dyebath exhaustion on the enzyme treated samples compared to raw material. The results of color measurements showed that the more concentration of enzyme used, the darker the color of dyed sample is. Interesting results were obtained in the studied topic.  相似文献   

3.
In this study, diallyldimethylammonium chloride (DADMAC), a quaternary ammonium salt monomer, is graft polymerized on 50?C50 Nylon-Cotton (NyCo) standard military fabric using atmospheric pressure glow discharge plasma to impart self-detoxification capability. Atmospheric pressure plasma?is used to induce free radical chain polymerization of the DADMAC monomer to introduce a graft polymerized network on the fabric with durable antimicrobial properties. Pentaerythritol tetraacrylate (PETA) is used as a cross-linking agent to obtain a highly cross-linked, durable polymer network. The presence of polyDADMAC on the fabric surface is confirmed using acid dye staining, SEM, and TOF?CSIMS. Antibacterial performance is investigated using standard AATCC Test Method 100 for both gram positive and gram negative bacteria. Results show 99.9?% reduction in the bacterial activities of Klebsiella pneumoniae and Staphylococcus aureus.  相似文献   

4.
Diallyldimethylammonium chloride (DADMAC) was free-radical copolymerized with acrylamide (AA) in water at a total monomer concentration of 4 mol/L and 40°C with different monomer feed compositions. Gelation occurred only for 20/80 DADMAC/AA monomer feed although crosslinking was observed for all monomer feed compositions. The gel point was at 51% conversion, and the swelling ratios of the resulting gels were quite high, from 1400 to 700. Addition of 2‐propanol as a chain‐transfer reagent reduced crosslinking and prevented gelation. These results are mechanistically discussed in connection with the cyclopolymerizability of DADMAC, and significant allylic hydrogen abstraction by the growing polymer radical characteristic of allyl polymerization is proposed.  相似文献   

5.
Summary: The synergy between magnetic field (MF) and electrostatic interactions on the kinetics of radical homopolymerization of acrylamide (AM), acrylic acid (AA), its ionized form acrylate (A) and diallyldimethylammonium chloride (DADMAC), as well as AM/AA, AM/A, DADMAC/AA, and DADMAC/AM copolymerizations was investigated. The application of MF during the polymerizations significantly increased the monomer consumption rate (Rp) of all monomers in homo and copolymerizations and the molar masses of polyAA and polyNaA. The molar mass of polyAM and the copolymer composition of any monomer combination remained unchanged by MF. The electrostatic interactions between ionic monomers and growing radicals dominate for the monomers and conditions studied here.  相似文献   

6.
紫外辐照接枝制备亲水性两性纳滤膜   总被引:2,自引:0,他引:2  
吴嘉杰  唐晶欣  曹绪芝  平郑骅 《化学学报》2009,67(15):1791-1796
通过紫外辐照在酚酞基聚芳醚酮(PEK-C)超滤膜表面引发自由基共聚反应, 依次接枝二甲基二烯丙基氯化铵(DADMAC)和对苯乙烯磺酸钠(SSS), 制成亲水性、表面载有两种不同电荷的纳滤膜. 通过测定膜的纯水通量和对不同盐溶液表观截留率的变化, 系统研究了单体浓度和接枝时间对膜的分离性能的影响. 结果表明, 用这种方法制成的亲水性两性纳滤膜对盐溶液的截留作用与两种单体在接枝液中的浓度和接枝时间有关. 膜对由高价同离子和高价反离子组成的盐表现出优良的截留作用.  相似文献   

7.
Nylon 6 and nylon 6,6 reaction equilibria depend in a complex way on water concentration and temperature. For example, data sets from six research groups reveal that the apparent equilibrium constant for polycondensation increases with water at low water concentrations, reaches a maximum, and then decreases as the water concentration rises further. In this article, semi‐empirical expressions are proposed to describe the experimentally observed equilibrium behavior for the five main reactions that occur during nylon 6 and nylon 6,6 polymerization. Nine side reactions involving amidine ends, cyclopentanone ends, and hydrated carboxyl ends are used to develop expressions that account for the influence of both water and temperature on these equilibrium constants. Excellent fit to the data, over the entire range of the available nylon 6 and nylon 6,6 literature data, suggests that the proposed equations will be helpful for modeling reaction equilibria for nylon 6/6,6 copolymerization.  相似文献   

8.
Adsorption and spontaneous polymerization of head- or tail-type surface active monomers having long methylene chains on colloidal silica and δ-alumina were investigated. Both head-type and tail-type ammonium monomers on silica in chloroform or tetrahydrofuran had the maximum adsorption on the respective adsorption isotherm. Above the monomer concentration giving the maximum adsorption, it was observed that the monomer formed micelles or clusters in bulk solution with removal of adsorbed water molecules from the silica surface. At the monomer concentration giving the maximum adsorption, heating the silica suspension containing the monomer at 40°C or 60°C in tetrahydrofuran or chloroform solution resulted in spontaneous polymerization. The composite particles formed by polymerization were observed to have many spots consisting of polymer on the surface. Therefore, it is suggested that the monomers are concentrated by micelle-like aggregation on the silica surface and consecutively spontaneous polymerization takes place. Adsorption of an anion-type monomer having a carboxyl group on δ-alumina, which exhibited a positive ζ potential in neutral aqueous solution, was higher than that on colloidal silica, but did not spontaneously polymerize on alumina. Received: 13 June 1998 Accepted in revised form: 19 August 1998  相似文献   

9.
Plasma-induced graft copolymerization of acrylic acid onto PE films was investigated. The influence of plasma treatment power, pressure, time, graft copolymerization time, and monomer concentration on polymerization yield was determined. A chemical shift of the Cls signal of Ar plasma treated and untreated PE films was revealed by ESCA, which also verified the presence of grafted PAAc. An increase in graft polymerization yield with plasma treatment time and power was found. Both the plasma treated film and the subsequently grafted film were shown to be hydrophilic. Only the grafted film, however, shows an invariably low contact angle. The decomposition of peroxides upon heating was followed by a simple first-order reaction. © 1993 John Wiley & Sons, Inc.  相似文献   

10.
Graft copolymers of poly(diallyldimethylammonium chloride), (poly-DADMAC), with acrylamide were synthesized using a ceric salt/nitric acid initiation system. The effects of concentration of initiator, monomer, and substrates were studied. Copolymers were characterized by viscometry and size-exclusion chromatography. The highest molecular weight ( M w ) of graft copolymer obtained was 1.70 × 106. The compositions of copolymers are dependent upon the ratios of the concentration of monomer to the concentration of substrate. The highest content of DADMAC monomer unit in the copolymer was 33 wt%.  相似文献   

11.
A series of copolymers of N,N-morpholine-N-2-(ethoxycarbonyl)allyl allyl ammonium chloride, N,N-morpholine-N-2-(ethoxycarbonyl)allyl allyl ammonium bromide, N,N-piperidyl-N-2-(ethoxycarbonyl)allyl allyl ammonium chloride, N,N-morpholine-N-2-(t-butoxycarbonyl)allyl allyl ammonium bromide and diallyldimethylammonium chloride (DADMAC) with acrylamide (AAm) were prepared in water at 50-56°C using 2,2'-azo-bis(2-amidinopropane)dihydrochloride (V-50). The ethyl ester monomers showed high cyclization efficiencies during copolymerizations. The tert-butyl ester derivatives showed high cross-linking tendencies. The molar fractions of allyl-acrylate monomers in the AAm: allyl-acrylate copolymers were higher than the one of DADMAC in the AAm:DADMAC copolymers. The intrinsic viscosities of the copolymers measured in 0.09 M NaCl ranged from 2.5 to 7.5 dL/g.  相似文献   

12.
二过碘酸合银(II)氧化还原引发丙烯酸甲酯在尼龙1010上接枝共聚合反应的研究刘盈海刘卫宏赵敏孟劲功(河北大学化学系保定071002)关键词二过碘酸合银(II)钾,尼龙1010,氧化还原引发,丙烯酸甲酯,接枝共聚目前Ce(IV)被认为是一种十分...  相似文献   

13.
Plasma-induced graft copolymerization of acrylic acid, which was incorporated into PE films, was investigated here. The influence of plasma conditions such as plasma treatment gases, power, pressure, time, monomer concentration, and graft copolymerization time on polymerization yield was determined. The samples were characterized by ESCA, IR, and water contact angle. A respective chemical shift of the C1s signal of Ar or O2 plasmatreated and untreated PE films was revealed by ESCA, in which the presence of the grafted PAAc was also verified. An increase in polymerization yield with plasma treatment duration and power was found. That the grafted copolymerization was limited to a very thin surface region was revealed by optical microscopy on the cross section of the grafted film. © 1993 John Wiley & Sons, Inc.  相似文献   

14.
This work reports on dyeing of nylon/elastane fabric with water-soluble phthalocyanines ( 1-4 ) bearing quinoline 5-sulfonic acid substituents on the peripheral or nonperipheral positions and determining the antibacterial efficiency of the phthalocyanine compounds and the dyed nylon/elastane fabrics. The light, washing, water, perspiration, and rubbing fastness properties of nylon/elastane fabrics dyed with phthalocyanines were also determined. The results showed that all dyed fabrics showed very good wet fastness values. The lightfastness value of the nylon/elastane fabric dyed with phthalocyanine dye ( 1 ) showed a much better value than the others. Also, the antibacterial efficiencies of the dyed nylon fabrics and the dye compounds were investigated against a gram-negative ( Escherichia coli ) and a grampositive ( Staphylococcus aureus ) bacteria by using disc diffusion method. The results showed that the dyed nylon/elastane fabrics and the compounds exhibited antibacterial activities against both bacteria.  相似文献   

15.
Atmospheric plasma‐induced graft polymerization was employed successfully to generate free radical on the surface of Kevlar® (poly‐(p‐phenylene terephthalamide or PPTA), and to initiate and control graft polymerization of cationic antimicrobial precursors diallyldimethylammonium chloride (DADMAC) or 3‐(trimethoxysilyl)propyl‐dimethyloctadecyl ammonium chloride (TMS) onto the fabric surface, which eliminates the need for separate processes that may involve thermal energy or UV irradiation. It was demonstrated that when the radiofrequency of the plasma power was 400 W, the radical density generated on the surface was 1015 to 1016 radicals cm?2, which were enough to generate a poly‐DADMAC or poly‐TMS with surface charge of at least 2 × 1017 N+/cm2, which is the minimum threshold for an effective cationic biocidal surface. In both cases, the grafted polymers were characterized and confirmed using SEM, FTIR, and XPS. The antimicrobial activity was measured using the AATCC Test Method 100, which showed that at least 3‐log reduction of bacteria colonies was achieved in the case of grafted poly‐DADMAC or grafted poly‐TMS on Kevlar®. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012  相似文献   

16.
Graft polymerization of 2-hydroxyethyl methacrylate was made onto plasma pretreated fabrics of cotton, silk, and polyester. Homopolymerization also took place during the graft polymerization, but the percent of the homopolymer formation was comparatively small. Therefore, kinetic analyses of graft polymerization were undertaken based on the first-order reaction of the monomer. Through a comparison of the rate constants which were obtained from the rate equation of the graft polymerization of 2-hydroxyethyl methacrylate, the dependence of plasma pretreatment on various factors and the resulting polymerization were clarified. Polymerizability was compared to that obtained with the Ce(IV) catalyst and without catalysts.  相似文献   

17.
采用油酸失水山梨醇酯(SPAN)-壬基酚聚氧化乙烯醚(OP)复合乳化剂与K2S2O8-Na2SO3氧化还原引发剂,进行二烯丙基二甲基氯化铵-丙烯酰胺反相乳液共聚合,测得单体的竞聚率为γDADMAC=0.14±0.11,γAM=5.05±0.66;在单体浓度为25─45%,引发剂浓度0.06—0.1%,乳化剂浓度为5—9%,聚合温度303K条件下,得到了共聚反应动力学方程:Rp=k[M]0.68[I]1.31[E]0.73,文中对上述结果做了解释.  相似文献   

18.
Diallyldimethylammonium chloride (DADMAC) was grafted onto polyethylene (PE) films by a double grafting procedure. The PE film was initially modified by grafting acrylic acid (AA), through a mutual irradiation method. AA-g-PE film, thus obtained was subjected to subsequent radiation grafting reaction of DADMAC, to give a DADMAC-g-AA-g-PE film having a comb-type structure. The influence of different conditions, such as the extent of AA grafting, DADMAC concentration, absorbed dose and dose rate, on the grafting yield of DADMAC was investigated. A maximum DADMAC grafting of 30% was achieved. The equilibrium degree of swelling (EDS) of the grafted films were gravimetrically determined. TGA and FT-IR techniques were employed to characterize the grafted PE films.  相似文献   

19.
Two new monomers (2‐methyl‐oxiranylmethyl)‐phosphonic acid dimethyl ester ( 3 ) and [2‐(dimethoxy‐phosphorylmethyl)‐oxyranylmethyl]‐phosphonic acid dimethyl ester ( 6 ) were prepared and used with dicyandiamide ( 7 ) and citric acid ( 8 ) to impart flame resistance to cotton plain weave, twill, and 80:20‐cotton/polyester fleece fabrics. Monomers 3 and 6 were prepared from methallyl chloride ( 1 ) and 3‐chloro‐2‐chloromethylpropene ( 4 ) respectively via a two‐step phosphorylation epoxidation sequence in 79.3 and 67.5% overall yields. 1H and 13C nuclear magnetic resonance (NMR) and gas chromatographic mass spectrometry (GCMS) data were used to confirm their structures. Decomposition of monomers 3 and 6 in nitrogen by thermogravimetric analysis (TGA) occurred at 110 and 220°C, respectively. The mixtures of 3 : 7 : 8 and 6 : 7 : 8 (in 2:1:1 ratio) exhibited peak‐curing temperatures by differential scanning calorimeter (DSC) at 125 and 150°C and the temperatures were deemed suitable for curing treated fabrics without marring them. Flame‐retardant treatments were applied by the pad‐dry‐cure methods. All untreated fabrics showed limiting oxygen index (LOI) values of about 18% oxygen in nitrogen. For formulations with monomer 3 , LOI values for the three types of treated fabrics were greater than 25.5% when add‐on values for the formulation were 17.4, 12.7, and 21.1%. For formulations comprising monomer 6 , LOI values were greater than 28.6% when add‐on values for the formulation were 18.3, 13.1, and 16.7%. With the formulation comprising monomer 3 , the three fabrics passed the vertical flame test when add‐on values were 21.6, 12.7, and 23.5%, respectively; and with the formulation comprising monomer 6 , they passed the vertical flame test when add‐on values were 13.8, 8.4, and 18.0%. In all cases char lengths of fabrics that passed the vertical flame test were less than 50% of original length and after‐flame time was 0 sec and after‐glow time was less than 2 sec. Published in 2007 by John Wiley & Sons, Ltd.  相似文献   

20.
Photopolymerization of methyl methacrylate (MMA) onto nylon 6 fiber by UV radiation in alcoholic solutions of water-methanol, water-ethanol, and water-n-propanol in the presence of fructose was investigated. The effects of monomer concentration, time of polymerization, fructose concentration, and effect of media have also been studied. Graft add-on (GAO) % greatly enhanced with an increase in monomer concentration and time. With fructose concentration it increases up to 15 mmol/L of fructose and thereafter falls. The GAO in the media is in the following order: W + M + F > W + E + F > W + P + F(W = water; M = methanol; E = ethanol; P = n-propanol). A probable mechanism has been suggested. It appears that the active site is formed on MMA which abstracts an H-atom from the nylon 6 backbone, giving rise to graft of MMA by mutual combination.  相似文献   

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