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1.
Synthesis and characterization of acrylic fibers-<Emphasis Type="Italic">g</Emphasis>-polyacrylamide
Graft copolymerization of acrylamide onto commercial acrylic fibers was carried out using benzoyl peroxide as a free-radical
initiator in aqueous medium within the 75–95 °C temperature range. In this study, the effects of initiator and monomer concentration,
the amount of fiber, polymerization time, and temperature on the graft yield were investigated. The optimum concentration
for initiator was found to be 2.0×10−3 mol/l and the optimum temperature of 85 °C. The activation energy of the reaction was calculated to as 35.81 kJ/mol at the
temperature interval of 75–95 °C. The structures and morphologies characterization of grafted fibers was investigated by Fourier
transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The thermogravimetric
analysis data showed that the thermal stability of the acrylic fibers increased with graft yield. The scanning electron photographs
showed that the homogeneous appearance of the fiber surface changed and a shell-like heterogeneous structure occurred at the
surface with an increasing degree of grafting. The moisture content, water absorption, dyeability, and antimicrobial activity
of grafted acrylic fibers were also reported. The results showed that grafting of polyAAm improved the moisture contain, water
absorption, dyeability, and antimicrobial activity of fiber. 相似文献
2.
Poly(acrylic acid) and poly(hydroxyethyl methacrylate) were introduced onto PET fabrics by UV-induced photografting to improve
its hydrophilicity. Several factors affecting the photografting were studied including irradiation energy, monomer, and photoinitiator
(PI) concentrations. ATR and ESCA analyses proved successful grafting of the two monomers onto PET. Morphology of fabric surface
was examined using FE-SEM. Both zeta potential and water wetting time of the grafted PET fabrics decreased with increasing
grafting yield. Also cationic dyeability of the grafted PET fabrics increased because of the increased electrostatic interactions
between the anionic dyeing sites and cationic dyes. 相似文献
3.
Chuan Ding Jian-Chun Zhang Xue-Qiang Liu Xin-Xing Feng Hua Zhang Kan Lai 《Fibers and Polymers》2014,15(9):1895-1901
Electron beam irradiation grafting of acrylic acid (AAc), acrylamide (AAm), and dimethyl vinylphosphonate (DMVP) onto poly(ethylene terephthalate) (PET) fabrics was performed using a high-energy electron accelerator. Parameters affecting the graft polymerization of PET fabrics, including absorbed dose and monomer concentration, were investigated. Fourier transform infrared spectroscopy analysis confirmed that the monomers were grafted onto the PET fabrics. The thermal behavior of the grafted PET fabrics was investigated with thermogravimetric analysis. Findings showed that grafting with AAm could improve the thermal stability of PET. The limiting oxygen index values and vertical flammability test results showed that PET fabric graft-polymerized with AAc could improve the flammability and prevent melt dripping. Grafting with AAm and DMVP could improve the flame retardation property of PET fabric. Scanning electron micrographs showed that the surface morphology of the PET fabric samples was significantly influenced by graft polymerization, and that grafting with AAc could promote the formation of residual char and impart an anti-dripping quality to PET fabrics. 相似文献
4.
Yebol Dauletov Kaldybek Abdiyev Zhexenbek Toktarbay Nurxat Nuraje Maryamgul Zhursumbaeva Bagdaulet Kenzhaliyev 《Fibers and Polymers》2018,19(10):2023-2029
N,N-diallyl-N,N-dimethylammonium chloride (DADMAC) and vinyl ether of monoethanolamine copolymer (VEMEA) was synthesized by radical polymerization in aqueous media using ammonium persulfate as initiator. Copolymers synthesis was carried out by varying monomer composition at low conversion level. The viscosity of high molecular weight products was measured in aqueous 1 M NaCl solution and it was increased with increasing DADMAC amounts in the copolymer due to increasing positive charge. The structure of the product was identified by FTIR, 1H, 13C-NMR spectroscopies and conductometric titration methods. We calculated monomer reactivity ratios with help of Finemann-Ross, Kelen-Tudos, and inverted Finemann-Ross methods. It was found that DADMAC is more reactive than VEMEA, therefore the amount of DADMAC in the copolymers always dominated regardless of the initial monomer ratio in solution and it was shown that the monomers are connected randomly in the polymer chain. The effect of various parameters such as monomer [M], initiator [I] concentrations, ratio of comonomers, etc. on polymerization was investigated systematically. So, the polymerization rate (Rp) equation was found to be Rp=k[M]2.6[I]0.6 where molar fractions of DADMAC and VEMEA was 90:10 and the temperature was 65 °C. Degree of polymerization was examined by using various monomers and initiator concentrations via the dilatometeric method. It was found that the polymerization rate increased directly with total monomer concentration and initiator content. 相似文献
5.
Metin Arslan 《Fibers and Polymers》2010,11(3):325-330
Poly(ethylene terephthalate) (PET) fibers were grafted with glycidyl methacrylate (GMA) using benzoyl peroxide as initiator. 1,6-diaminohexane (HMDA) was then covalently attached to this GMA grafted PET fibers. Variations of time, temperature, initiator and monomer concentrations were investigated. HMDA-GMA-g-PET fibers were used as a new sorbent for removal of Cr(VI) ions from aqueous solutions through batch adsorption method. Effects of various parameters such as pH, treatment time, and initial ions concentration on the adsorption amount of ions onto reactive fibers were investigated. The adsorption rates of Cr(VI) ions were much higher on the HMDA-GMA-g-PET fiber than on GMA-g-PET and ungrafted PET fiber. Within 60 min, at pH 3, Cr(VI) was removed by 98 % while the initial concentration of ions was at 25 mg/l and by 94 % at 400 mg/l. The Cr(VI) ions adsorbed were easily desorbed by treating with 1M KOH within 10 min. 相似文献
6.
Continuous photografting onto polypropylene fabrics in the absence of inert gases was carried out to improve hydrophilic property
of PP fabrics, which was padded with a formulated solution of 2-hydroxyethyl methacrylate(HEMA) and benzophenone as a monomer
and a photoinitiator, respectively. The grafting yield increased with increases in benzophenone concentration up to 30 % on
the weight of the monomer and UV energy up to of 38 J/cm2, while 30 % HEMA concentration was optimal for the grafting efficiency. The physicochemical properties of the grafted PP
fabrics were monitored by FT-IR, SEM, zeta potential, and dyeability to a cationic dye. The grafting increased O1s/C1s content and remarkably produced more negative zeta potentials compared with the pristine PP fabric. Also the grafted PP showed
the increased dyeability to cationic dyes with increasing graft yield resulting from the enhanced electrostatic interaction
between the dyes and negatively charged surface of the grafted PP fiber. In addition, improved hydrophilic property of grafted
PP fabrics was ascertained by more rapid water wetting time and higher water absorbency. 相似文献
7.
8.
Functionalized poly(ethylene terephthalate) (PET) fibers were synthesized by grafting of maleic acidmethacrylamide (MAA-MAAm)
monomer mixtures by using benzoylperoxide as initiator onto PET fibers in an aqueous medium. The functionalized fibers were
characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimeter, and
scanning electron microscopy. The effects of reaction conditions, such as monomer mixture ratio, monomer mixture and initiator
concentration, polymerization time, and temperature on grafting were investigated. In alone grafting of MAA, grafting was
not observed. However, the use of MAAm as a comonomer increased the amount of MAA inserted to the PET fiber up to 40.7 %.
An increase in the temperature between 75 and 95 °C and also, increase in monomer mixture concentration between 0.50 and 1.00
M increased the grafting rate and saturation graft yield. The graft yield has shown an increase up to an initiator concentration
of 1.0×10−2 M and decreased afterwards. The grafting increased the dyeability with disperse, acidic and basic dyes, and water absorption
capacity but decreased the thermal stability of the fibers. 相似文献
9.
Haydar U. Zaman Mubarak A. Khan Ruhul A. Khan Sushanta Ghoshal 《Fibers and Polymers》2012,13(5):593-599
Coir fibers were modified with methyl acrylate (MA) mixed with methanol (MeOH) under thermal curing method at different temperatures (40?C80 °C) for different curing times (20?C60 min). A series of solutions of different concentrations of MA in methanol along with 2 % benzoyl peroxide, were prepared. Monomer concentration, curing temperature, and curing time were optimized with the extent of grafting of monomer and mechanical properties of cured fiber and found to be 30 % MA, 60 °C and 40 min curing time registered as better performance (Grafting (Gr) = 5.7 %, tensile strength (TS) = 72 %, elongation at break (Eb) = 88 %) than those of untreated fiber. For further improvement of the properties, untreated coir fibers were pretreated with gamma and UV radiations at different doses and then pretreated fibers were soaked in the optimized monomer and cured under optimum conditions. Coir fiber pretreated with UV radiation and grafted with optimized monomer showed the best properties such as Gr (7.12 %), TS (132 %), and Eb (153 %) over raw fiber. Water uptake and simulated weathering test of untreated and treated coir fibers were studied. 相似文献
10.
In this paper, the morphological transformations in Hibiscus sabdariffa stem fiber on graft copolymerization with acrylonitrile (AN) and its binary mixture with methyl acrylate (MA) and acrylamide
(Aam), using ceric ammonium nitrate — nitric acid initiator system has been reported. Different reaction parameters such as
temperature, time, initiator concentration, monomer concentration and pH were optimized to get the maximum graft yield (Pg:28.0)
and used in binary monomeric mixture to further improve the properties. The graft copolymer thus formed were characterized
by FTIR, SEM, XRD, TGA, and DTA techniques. The percentage crystallinity and crystallinity index were found to decrease with
increase in percentage grafting. The graft copolymer were found to be moisture, chemical and thermal resistant for various
advanced applications. 相似文献
11.
An efficient, simple and facile process, i.e., suspension grafting polymerization combined with melt-blown technique, was employed to synthesize Polypropylene-g-(acrylic acid-co-acrylamide) nonwoven fabrics [PP-g-(AA-co-AM) nonwovens]. In this study, the grafting mechanism and the effect of synthesis parameters on grafting percentage (GP) were investigated. The as-synthesized products were characterized by melt flow rate (MFR), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), water contact angle (WCA) and thermalgravimetric analysis (TGA). Besides, the uptake properties of metal ions (i.e., Ba2+, Cu2+, Ni2+, Mg2+, Al3+, Ca2+) on the PP-g-(AA-co-AM) nonwovens in dynamic condition were studied. Results of FTIR showed that AA and AM were successfully grafted onto the PP surface. The decrease in WCAs of the grafted nonwovens with the increasing GP indicated that (AA-co-AM) side chains existed as the hydrophilic component. TGA results revealed that no significant change in thermal stability was found in grafted PP samples. The synthesis experiments showed that the highest GP was obtained at grafting time 3 h, water 3 ml/g, xylene 15 wt%, benzoyl peroxide 0.5 wt%, AA, AM 30 wt% and AA: AM 1:1, with a GP of 16.7 %, and a grafting efficiency of 67 %. However, MFR measurement and SEM image demonstrated that PP-g-(AA-co-AM) nonwovens with the highest GP showed almost no mechanical strength existed between filaments resulting in the occurrence of deformation and contraction of nonwovens, and breaking up into small pieces. Comprehensively, the optimal GP was 8.7 %, and the corresponding PP-g-(AA-co-AM) nonwovens exhibited higher metal ions uptake capacity than pristine PP nonwovens in the dynamic adsorption process. 相似文献
12.
Present study is focused on the preparation of two layers composite wound dressing for drug release. The outer layer is made of hydrogel which contains of drug and the core layer is made of fabric. The two layers structure of composite dressing is formed by grafting of polyacrylamide-co-acrylic acid hydrogel on cotton fabric using ammonium per sulphate (APS) as chemical initiator and polyethylene glycol (PEG) as crosslinker. The major factors affecting graft copolymerization of hydrogel on cotton fabric are optimized by varying concentration of monomers & initiator, reaction temperature and addition time of crosslinker. Maximum grafting of hydrogel is obtained at 5 % (w/v) APS and 15 % acrylamide/acrylic acid (1:1 w/w ratio) concentration. The FTIR spectra of composite dressing shows characteristics peak of acrylic acid and acrylamide. The composite wound dressing material is loaded with model drug bovine serum albumin (BSA) and drug release behaviour is studied at different pH. The dressing shows drug release in different pH with maximum release of drug in acidic medium. 相似文献
13.
Aramid fibers have been known to difficult to dye with conventional dyes and dyeing techniques because of its extremely high
crystallinity and compactness. In order to make the aramid fibers dyeable to a bright color in deep shade, meta-aramid fabrics were photografted under continuous UV irradiation with dimethylaminopropyl methacrylamide (DMAPMA) and benzophenone
as a monomer and a hydrogen-abstractable photoinitiator respectively. Several factors affecting the photografting treatment
of the meta-aramid fabrics were investigated including monomer and photoinitiator concentrations. ATR, ESCA and SEM analysis
indicated significant alterations on the chemical structure and atomic composition of the photografted fabric surface and
the fabric surface was covered with the grafted polymers. While the pristine meta-aramid fabrics showed no appreciable dyeability
to the α-bromoacrylamide type reactive dyes, the grafted aramid fabrics showed the remarkably enhanced dyeability to the reactive
dyes, which was proportional to the graft yield indicating the covalent bond formation between the dyes and the secondary
amino groups in the grafted DMAPMA. In case of C.I. Reactive Red 84, a K/S value of 14.8 can be obtained with the grafted meta-aramid fabrics with a graft yield of 7.6 % (w/w). Also and the color
fastness properties of the dyed fabrics was excellent in the conditions of washing, rubbing and solar irradiation. 相似文献
14.
Dibromopropionamide groups of C.I. Reactive Red 136 were dehydrobrominated to obtain bisbromoacrylamide groups. Photografting yield of the modified dyes onto cotton increased with the addition of acrylamide comonomer, presumably reducing the steric hindrance between the dyes with bulky chromophores. The acrylamide-assisted grafting was more prominent with increasing degree of the functionality. The optimum grafting was obtained with 2.5 molar ratio AAm and 7 % photoinitiator with respect to 0.03 mol/l dye under a UV energy of 25 J/cm2. The grafting yield and K/S of the grafted cotton with C.I. Reactive Red 83 was lower than that with the modified Red 136 at the same degree of functionality 2.0, probably because the relatively larger chromophore of the Red 83. In addition, the washing, rubbing and light fastness of the grafted cotton fabrics with the modified Red 136 were higher than the adsorption-based conventional dyeing, which was more pronounced as the degree of functionality increased. 相似文献
15.
The inherent properties of rayon fibre have been changed with additional properties through graft copolymerization of acrylamide, AAm, by chemical method using ceric ammonium nitrate/nitric acid, (CAN/HNO3), as a redox initiator and γ-radiation induced mutual method. Reaction conditions such as monomer and initiator concentration, liquor ratio, temperature and time of reaction, amount of radiation dose have been optimized with respect to percentage of grafting. Maximum percentage of grafting (Pg), (40 %) using CAN/HNO3 was obtained at [CAN]=31.92×10?3 moles/l, [HNO3]=79.36×10?2 moles/l, [AAm]=14.07×102 moles/l in 20 ml of H2O at 45 °C within 120 min while in case of radiation induced method, maximum Pg (30 %) was obtained at higher monomer concentration (28.14×10?2 moles/l) and time (180 min) in 10 ml of H2O at room temperature with total dose exposure of 11.178 kGy. The graft copolymers were characterized by FTIR, thermogravimetric and scanning electron micrographic analysis. Swelling behaviour in water, methanol, ethanol, acetone and DMF and dyeing and flame retarding properties of rayon fibre and grafted rayon fibre were investigated. Percent dye uptake (71.8 %) was found to be higher than that observed for the pristine fibre (57.4 %) and the grafted fibre after post phosphorylation reaction showed excellent flame retarding properties. 相似文献
16.
Graft copolymerization of granular allyl starch with carboxyl-containing vinyl monomers using H2O2/Fe2+ initiator in aqueous dispersion was investigated for enhancing grafting efficiency of the copolymerization. The graft copolymerization
was evaluated in terms of grafting efficiency, grafting ratio, and conversion of monomer to polymer. Influences of both allyl
etherification of starch and structures of vinyl monomers used on the copolymerization were revealed. Variables such as molar
ratio of Fe2+ to H2O2, initiator concentration, monomer concentration, polymerization temperature, and time of the graft copolymerization were
also studied. It was found that allyl etherification of starch enhanced the grafting efficiency and grafting ratio evidently.
Acrylic acid exhibited the greatest grafting efficiency and ratio for the copolymerization after starch was allyl-etherified.
The copolymerization should be carried out under the protection of nitrogen gas at 30–35 °C for 3 h by using H2O2/Fe(NH4)2(SO4)2 as initiator. Preferred molar ratio of H2O2/Fe(NH4)2(SO4)2/anhydroglucose was in a range of 20/1/1000 to 60/3/2000. 相似文献
17.
Dimethylaminopropyl methacrylamide (DMAPMA) was grafted onto PET/wool blend fabrics by continuous UV irradiation. Union dyeing
of the photografted fabrics was investigated using three reactive dyes of α-bromoacrylamide reactive groups. The influence of grafting yield, DMAPMA concentration, NaCl amount, pH value, and dyeing
temperature on the dyeability was evaluated. The dyeability of both PET and wool components was improved significantly by
the DMAPMA photografting and successive reactive dyeing. Although the dyeability of the PET component in the blend substantially
was improved with higher grafting, equal dyeability between PET and wool was difficult to achieve due to more facile grafting
and higher reactivity of the wool component compared with the modified PET component. However, the color fastness of the PET/wool
blend fabric was excellent for all three colors. This study may offer a way to achieve union dyeing of PET/wool blend fabrics. 相似文献
18.
为探明种间嫁接生产应用可行性,以解决连作咖啡园再植植株长势弱、死亡率高的问题,布置了以未嫁接的中粒种咖啡热研3号实生后代为对照,查理种16号为砧木、中粒种咖啡热研3号实生后代为接穗的种间嫁接大田试验。经过5 a的田间性状观测,结果表明：1年生种间嫁接植株株高、茎粗、冠幅、最长一级分枝长度大于未嫁接植株,但差异未达显著,种间嫁接植株一级分枝对数、最长一级分枝节数显著大于未嫁接植株;2015年单节果实数未嫁接植株显著高于嫁接植株,其余年份（2014年、2016年）差异不显著;干鲜比、百粒重、单株鲜果产量两者间差异不显著。虽然嫁接植株2015年单节果实数显著低于未嫁接植株,但种间嫁接促进了中粒种咖啡的生长,增加了单株结果节数,因而嫁接植株单株鲜果产量未显著减少。综上,嫁接不影响中粒种单株鲜果产量和果实的品质性状,该组合的种间嫁接在生产中推广应用是可行的。 相似文献
19.
Bohdan Volynets Hamza Nakhoda Mustafa Abu Ghalia Yaser Dahman 《Fibers and Polymers》2017,18(5):859-867
The purpose of this study is to synthesize grafted Bacterial Cellulose (BC) nanofibers using Atom Transfer Radical Polymerization (ATRP) reinforced into poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel matrix. Nanofibers grafting polymerizations were conducted in the presence of the catalyst CuCl/CuBr and the initiator 2-bromoisobutyrylbromide (2-BiBr). Degrees of substitution (DS) of BC-macroinitiators were quantified using both elemental analysis and gravimetric method. FTIR results confirmed BC nanofibers’ surface modifications of both initiator and hydroxyethyl methacrylate (HEMA) grafts. X-ray spectroscopy further confirmed the increase in carbonyl content after PHEMA-grafting polymerization. Results of the gravimetric analysis showed an increase in the weight of the grafted BC upon increasing reaction time. Furthermore, the change in the swelling ratio percentages of the reinforced composites product (BC-MI-3-g-PHEMA-1.5) was considerably higher based on reaction time. Slight increase in the swelling ratio of BC-MI-3 nanofibers was observed after 48 hours to reach 31 %. Moreover, results of thermal gravimetric analysis (TGA) demonstrated that decomposition temperature at 50 % weight loss (T50) decreased to 350 °C for BC-MI-3-g-PHEMA-1.5. These characteristics demonstrate potentials for applications in the biomedical fields including drug delivery and wound care. 相似文献
20.
Songmin Shang Lei Zhu Weiguo Chen Lingmin Yi Dongming Qi Lei Yang 《Fibers and Polymers》2009,10(6):807-812
Silk fibrillation, one major weakness of silk fibers, can lead to undesirable fabric appearance. In this research, an effective
method for reducing the fibrillation of silk fibers through the graft copolymerization with methyl methacrylate (MMA) has
been developed. The major copolymerization factors such as the initiator concentration, MMA monomer concentration, reaction
time and temperature were investigated. An AATCC Crockmeter was used to rub the fabric to simulate the abrasion in production
to generate the fibrillation. The microscope observation and the evaluation of fibrillation index (FI) were applied to assess the degree of fibrillation of silk fibers. The optimum graft copolymerization factors were obtained.
Instrumental analyses, such as FTIR, TG and SEM, proved that the silk fabric had been successfully grafted with MMA monomers.
The fibrillation of the grafted silk fibers was considerably reduced since the coated PMMA can protect the silk fiber. In
addition, the physical properties such as the crease recovery, breaking strength, and the breaking length of the grafted silk
fabrics were also improved. 相似文献