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1.
真丝织物阳离子接枝共聚 总被引：7，自引：1，他引：6
研究了阳离子化合物DMC和DMDAAC对真丝织物的接枝共聚。选用过硫酸钾作引发剂,采用轧烘焙的工艺,对影响接枝反应的影响进行了探讨,从而寻求出适宜的工艺条件,并以处理后的织物性能进行了考察。 相似文献
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Cationic acetylated starch‐g‐poly(styrene‐butyl acrylate) surfactant‐free emulsion (CAS‐g‐poly(St‐BA)) was synthesized by graft copolymerization of styrene (St) and butyl acrylate (BA) onto CAS using FeSO4–H2O2 redox initiator. The maximum graft of 55.68% was derived when H2O2 concentration, monomer concentration, and St/BA ratio were 9%, 130%, and 1:1, respectively. The results obtained from FTIR, NMR (H1 NMR and C13 NMR), XRD, SEM, and thermogravimetric analysis (TGA‐DTG) confirmed graft copolymerization of St and BA onto CAS. And it was demonstrated that film‐forming properties of starch were greatly improved via grafting St and BA onto starch. It was also found that paper sized with CAS‐g‐poly(St‐BA) exhibited higher ring crush index and bursting strength than paper sized with cationic potato starch (CS) and CAS, as well as much lower water absorption, which is further verified by contact angles results. 相似文献
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Vandana Singh Ashutosh Tiwari Sadanand Pandey Somit Kumar Singh 《Starch - St?rke》2006,58(10):536-543
Using a very low concentration of potassium persulfate as initiator, acrylamide could be efficiently grafted onto potato starch under microwave irradiation and for the grafting O2 removal from the reaction vessel was not required. Under optimal conditions, grafting and efficiency observed were 160% and 89%, respectively. Grafted starch was characterized by using Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD) and thermogravimetric analysis (TGA). It was observed that the microwave irradiation could significantly accelerate the synthesis of starch‐graft‐poly(acrylamide), because under identical conditions no grafting was observed in a conventional procedure. Viscosity, shear stability and water/saline solution retention of the microwave‐synthesized grafted starch were studied and compared with that of the parent starch. 相似文献
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Graft copolymerization of 2‐(dimethylamino)ethyl methacrylate onto potato starch was carried out in an aqueous medium using a potassium permanganate/sulfuric acid initiation system. The grafting percentage and grafting efficiency were determined as functions of the concentrations of potassium permanganate, sulfuric acid and the monomer, and also polymerization temperature and time. The IR spectrum of the graft copolymer showed the peaks characteristic of the grafted chains. The grafting percentage and grafting efficiency increased and then decreased with increasing the concentrations of potassium permanganate, sulfuric acid, and the monomer, as well as polymerization temperature. The grafting reaction was characterized by an initial fast rate followed a lower rate which leveled off after a certain time. The overall activation energy for the grafting was estimated to be 66.9 kJ/mol. 相似文献
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Alummoottil N. Jyothi Janardhanan Sreekumar Subramoney N. Moorthy Moothandaserry S. Sajeev 《Starch - St?rke》2010,62(1):18-27
Response surface methodology (RSM) was employed for the synthesis of cassava starch‐graft‐poly(acrylamide) using ceric ammonium nitrate as free radical initiator. Concentration of acrylamide, concentration of ceric ammonium nitrate, reaction temperature and duration of reaction were optimized using a 4‐factor 3‐level Box‐Behnken design. The dependent variables were percentage grafting (%G) and grafting efficiency (GE). Second order polynomial relationships were obtained for %G and GE, which explained the main, quadratic and interaction effects of factors. The highest%G and GE obtained were 174.8% and 90.7%, respectively. The optimum values of parameters predicted through RSM were 20 g acrylamide/10 g dry starch, 3.3 g/L ceric ammonium nitrate, 180 min reaction duration and 45ºC temperature with a %G of 190.0. For GE, the predicted levels of factors for the optimum value of 90.8% were 17.5 g acrylamide/10 g dry starch, 4.1 g/L ceric ammonium nitrate, 180 min reaction duration and 55ºC temperature. The graft reaction was confirmed by FTIR analysis, where the absorption bands corresponding to the C=O stretching and N‐H bending of the –CONH2 group were observed. Scanning electron microscopic studies on grafted starches revealed that the granular structure of the starch was affected by the reaction. X‐ray diffraction analysis showed that the crystallinity of starch was decreased as a result of grafting and the reduction was higher for the grafted starches with higher percentage grafting. 相似文献
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A series of graft copolymers of starch with polyacrylamide was made by using a K2S2O8 initiation system in inverse emulsion. The corresponding anionic graft copolymers, which have a different hydrolysis degree, are prepared by alkaline hydrolysis of the uncharged graft copolymers. Adequate hydrolytic conditions including type and amount of hydrolyzing agent, temperature, and time were studied. These graft copolymers have been tested for their temperature sensitivity, salt tolerance and shear stability, and a comparison has been made with ungrafted polyacrylamide (PAM). Experiments showed that a high hydrolysis degree can be obtained in a shorter time when NaOH and Na2CO3 were used together as hydrolyzing agents, and the highest solution viscosity was observed when the hydrolysis degree of the graft copolymers was approximately 30%, . In addition, the shear stability, temperature sensitivity and salt tolerance in the graft copolymers were also investigated. 相似文献
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In order to enhance the grafting efficiency of graft copolymerization of granular cornstarch with acrylic acid (AA) for improving the adhesion and film properties of starch‐g‐poly(acrylic acid) used as sizing agent, the esterification of hydrolyzed starch with acryloyl chloride was applied before graft copolymerization. The influence of three common initiators on the copolymerization were also studied. The initiators included ceric ammonium nitrate [Ce(NH4)2(NO3)6], hydrogen peroxide/ferrous ammonium sulfate [H2O2/FeSO4 · (NH4)2SO4], and potassium persulfate/sodium bisulfite [K2S2O8/NaHSO3]. It was found that acryloylation of starch before the copolymerization was an effective method for substantially enhancing the grafting efficiency and improving the performances such as adhesion‐to‐fibers and mechanical properties of grafted starch film. The acryloylation could increase the efficiency to 67–81% when the degree of substitution (DS) of acryloylated starch ranged from 0.010 to 0.036. The adhesion to polyester and cotton fibers reached their maximum at DS = 0.010 and 0.022, respectively. Strong and tough film was obtained when the DS value was in a range of 0.010–0.022. H2O2/FeSO4 · (NH4)2SO4 redox system was more appropriate for initiating the copolymerization of acryloylated starch with AA. 相似文献
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Commercial cornstarch was alkenylsuccinylated with alkenylsuccinic anhydride to different degrees of substitution (DS) and then the products were graft‐copolymerized with acrylic acid for investigating the effects of starch alkenylsuccinylation on the graft copolymerization with vinyl monomer, as well as on paste viscosity and film properties of alkenylsuccinylated starch‐g‐poly(acrylic acid) (ASS‐g‐PAA). The number of carbon atom of alkenyl in alkenylsuccinates considered was 8 and 12, corresponding to octenylsuccinylation and dodecenylsuccinylation of starch, respectively. The graft copolymerization was accessed by grafting efficiency, grafting ratio, and conversion of monomer to polymer, and the film properties of ASS‐g‐PAA considered included tensile strength, breaking elongation, and work‐to‐break. Experimental results demonstrated that the alkenylsuccinylation showed marked effects on the copolymerization, paste viscosity, and film properties. It resulted in increased grafting efficiency, stable paste viscosity, and strong starch film. Carbon‐chain length of the alkenyl and DS value of the alkenylsuccinates also exhibited evident effects on the copolymerization and film properties. Octenylsuccinylation of starch before the copolymerization was superior to dodecenylsuccinylation in improving the efficiency and film properties. Low levels of octenylsuccinylation could be utilized to increase the efficiency of the copolymerization and improve the properties of starch film. 相似文献
9.
对阳离子染料用下混纺比例为75／25、50／50、25／75的丙烯腈接枝蚕蛹蛋白纤维／蚕丝混纺纱线的染色性能进行了染色试验，分析了pH值、电解质浓度等工艺凶素对纱线卜染率的影响，并进行了上染速率曲线和吸附等温线的测定。 相似文献
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A novel starch graft copolymer containing sulfobetaine moieties in the side chains was synthesized by grafting the sulfobetaine zwitterionic monomer 3‐dimethyl(methacryloyloxyethyl) ammonium propane sulfonate (DMAPS) onto potato starch in the presence of the ceric ammonium nitrate (CAN) / acid initiation system. The effects of the concentrations of CAN and DMAPS, the pH of the reaction medium and the polymerization temperature on the grafting reactions were investigated in terms of the grafting percentage (GP) and grafting efficiency (GE). When the CAN concentration, the pH of the reaction medium or the reaction temperature increased, GP and GE were found to first increase and then to decrease. The increase of DMAPS concentration resulted in a significant enhancement of GP and GE. Furthermore, the thermal degradation of such graft copolymer was studied under air atmosphere at various heating rates, and the corresponding activation energy of the degradation was determined by Ozawa's method. 相似文献
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A synergetically acting new flocculant on the basis of starch‐graft‐poly(acrylamide)‐co‐sodium xanthate (CSAX) was synthesized by grafting copolymerization of crosslinked corn starch, acrylamide (AM), and sodium xanthate, using epichlorohydrin (EPI) as cross‐linking agent and ceric ammonium nitrate (CAN) as polymerization initiator in aqueous solution. The effects of some factors, such as crosslinker, initiator, AM, NaOH, on the %Tr (turbidity removal rate), %Trd (turbidity removal rate of a water sample which has both turbidity and heavy metal ions %Hr (heavy metal ion removal rate) and %Hrd (heavy metal ions removal rate of water which has both heavy metal ions and turbidity), are investigated. As proven by FTIR and elemental analysis, the CSAX can be successfully synthesized and can remove both turbidity‐causing substances and heavy metal ions from aqueous solutions. Under optimum synthesis conditions CSAX exhibits excellent performance, i.e. %Tr = 98%, %Trd = 98.4%, %Hrd = 99% and %Hr = 91.6%, respectively. 相似文献
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NatA is the major N-terminal acetyltransferase of the yeast Saccharomyces cerevisiae. In this study, we took advantage of our recent data on N-terminal acetylation of proteins of the yeast protein map to update the list of proteins with known NatA-dependent acetylation status. Furthermore, using the information available on the acetylation status of 100 novel proteins, we re-examined the rules for acetylation by NatA. The results refine our previous knowledge on NatA substrate specificity depending on the N-terminal and penultimate residues. In particular, we found that the acetylation frequencies of Ser-, Thr- and Ala-, the three residues most often acetylated by NatA, are higher than previously reported. In addition, comparison of the N-terminal region of acetylated and non-acetylated proteins revealed differences in amino acid composition that extend over the 25 first amino acid residues: acetylated proteins are characterized by a higher frequency of glutamate and glutamine and a lower frequency of lysine, arginine and histidine. We suggest that the particularities in amino acid composition of the N-terminal region of acetylated proteins facilitate its interaction with the Nat1p subunit of NatA and its guidance to the catalytic subunit Ard1p. 相似文献
17.
Superabsorbent polymers (SAPs) were prepared from cassava starch by graft copolymerization of acrylamide on to starch using ceric ammonium nitrate (CAN) as free radical initiator, followed by alkali saponification. The reaction parameters such as concentration of acrylamide, concentration of CAN, temperature, and duration of polymerization reaction were optimized for maximum water absorbency using a 4‐factor 3‐level Box‐Behnken design. The highest values of percentage grafting and absorbency obtained were 174.8% and 425.2 g/g, respectively. The polymers were characterized by determination of grafting efficiency, N‐content, acrylamide content, FTIR analysis, SEM and XRD analyses. Thermogravimetric analysis (TG) showed that the SAP has higher thermal stability. The rate of water absorbency and the swelling behaviour of the SAP under different conditions of pH, and different salts were determined. The de‐swelling pattern of the hydrogels over different time durations was also determined. 相似文献
18.
Ping‐Jun Zhang Zhen‐Gang Zhao Shu‐Juan Yu Shu‐Zhen He 《International Journal of Food Science & Technology》2012,47(3):475-481
The formation and degradation of N‐(1‐Deoxy‐d ‐xylulos‐1‐yl)glycine and N‐(1‐Deoxy‐d ‐xylulos‐1‐yl)proline, derived from the secondary amine Maillard reaction in xylose‐amino acid model solutions, were detailed in this study. The identification and quantitative analysis of N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)glycine and N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)proline were carried out using high‐performance anion‐exchange chromatography and high‐performance liquid chromatography. The formation of intermediate and advanced products derived from N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)glycine and N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)proline was also tested using an UV‐Vis spectrophotometer to gain a better comparing of the degradation process of the two important Maillard reaction products using thermal treatment. Results showed that the degradation of N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)glycine was more significant than N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)proline. Moreover, xylose was tested in the degradation products of both N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)glycine and N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)proline, which indicated that the degradation of N‐substituted 1‐amino‐1‐deoxyketoses was a reversible reaction to form reducing sugar. 相似文献
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N,N‐Bis(2‐hydroxyethyl)formamide (BHF) was synthesized efficiently and used as a new plasticizer for corn starch to prepare thermoplastic starch (TPS). The hydrogen bond interaction between BHF and starch was proven by Fourier‐transform infrared (FT‐IR) spectroscopy. As detected by scanning electron microscopy (SEM), starch granules were completely disrupted and a continuous phase was obtained. The crystallinity of corn starch and BHF‐plasticized TPS (BTPS) was characterized by X‐ray diffraction (XRD). The thermal behavior of glycerol‐plasticized TPS (GTPS) and BTPS was investigated by differential scanning calorimetry (DSC). The water resistance of BTPS was better than that of GTPS. Generally, at low relative humidity (RH), the tensile strength of BTPS was higher than that of GTPS. At high RH, the elongation at break of BTPS was higher than that of GTPS. 相似文献