魔芋粉-丙烯酸-丙烯酰胺接枝共聚合成高吸水树脂

以魔芋粉,丙烯酸和丙烯酰胺等为原料,经接枝聚合合成了魔芋粉－丙烯酸－丙烯酰胺类超强吸水性树脂。讨论了引发剂,交联剂,丙烯酸,丙烯酰胺等用量以及反应时间和反应温度等因素对树脂吸水性能的影响。结果表明: 在魔芋粉与单体质量比为1:4,引发剂用量为0.35%（占单体的质量）,丙烯酸/丙烯酰胺（质量）为1:1,丙烯酸中和度为80% ,反应温度为55～65℃,交联剂用量为0.75%（占单体的质量）的条件下,制得的SAP吸去离子水可达720g/g,吸0.9%的NaCl溶液为110g/g。     

玉米淀粉接枝丙烯酰胺制备高吸水性树脂

用硝酸铈铵作引发剂,通过水溶液聚合法制得了玉米淀粉接枝丙烯酰胺高吸水性树脂。研究了交联剂及引发剂用量、碱用量、反应温度以及反应时间等对吸水率的影响。得到的最佳反应条件为:交联剂和引发剂与丙烯酰胺的摩尔比分别为1.0×10-5和3.0×10-3,碱与丙烯酰胺的摩尔比为1.50,反应温度60℃,反应时间2 h。在室温下制得的高吸水树脂,30 m in每克吸蒸馏水和自来水分别约为其自身质量的600和170倍。     

麦秸秆纤维素与丙烯酸接枝共聚制备耐盐性吸水树脂的研究

应用小麦秸秆与丙烯酸接枝共聚制备了耐盐性吸水树脂,进行了结构表征,研究了单体配比、丙烯酸中和度、引发剂和交联剂用量以及反应温度对吸盐水倍率的影响。研究发现,接枝共聚的适宜条件为:丙烯酸单体与麦秸秆质量比为8∶1,丙烯酸中和度为70%,引发剂过硫酸钾-硫代硫酸钠的用量为单体的3.5%,交联剂N,N-亚甲基双丙烯酰胺用量为单体质量的0.24%,反应温度为70℃。在此条件下制备的树脂吸盐水倍率最高,吸盐水(CNaC l=0.9%)可达68 g/g,可应用于医疗卫生等方面。     

具有吸水保水功能的改性魔芋共聚物包膜缓释尿素的制备及其性能研究

以烯丙基硫脲改性魔芋葡甘聚糖为包膜剂制备包膜缓释尿素。对包膜缓释材料进行扫描电子显微镜(SEM)表征,并分析其吸水性能;评价温度及土壤水含量对包膜缓释尿素氮素溶出率的影响,利用土柱淋溶法检测包膜缓释尿素的缓释效果,并分析缓释尿素对白菜的生长影响。结果表明,烯丙基硫脲接枝魔芋葡甘聚糖在接枝率为35%~45%时,吸水性能最好,吸水量高达794 g/g;随着温度和土壤水含量的升高,包膜缓释尿素氮素溶出率逐渐增加;氮素溶出具有典型的缓释肥溶出特征,表现出良好的缓释效果;白菜对缓释尿素中氮素的利用率提高。     

魔芋葡甘聚糖及其衍生物的应用研究进展

综述了魔芋葡甘聚糖(KGM)及其衍生物在食品、医药及环保等领域的应用,表明KGM具有较高的学术研究价值及广阔的应用前景。     

Preparation of konjac glucomannan ester of palmitic acid and its emulsification

Various degrees of palmitoylated konjac glucomannan (PKGM) are prepared by a heterogeneous method. Differential thermal analysis thermographs show PKGM having 0.51 degrees of substitution (DS) gave a new crystalline peak at higher temperature. With the increase of DS, the former crystalline state of konjac glucomannan will disappear; PKGM only shows the new crystalline state. Furthermore, the effect of the DS of PKGM on its emulsifying ability has been investigated in the water in oil and oil in water systems. It is demonstrated that it is a kind of good water in oil emulsifier, with the DS ranged between 1.00 and 1.70, whereas DS < 0.50. It is a kind of good oil in water emulsifier and an interesting phenomenon appears in the water in oil system. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1035–1038, 1998     

Preparation of bentonite–poly[(acrylic acid)‐acrylamide] water superabsorbent by photopolymerization

A novel bentonite–poly[(acrylic acid)‐acrylamide] superabsorbent composite with water and salt solution absorbencies of 450 and 108 times its own weight, respectively, was successfully synthesized by photopolymerization of acrylic acid with acrylamide in the presence of bentonite powder using 30 min of ultraviolet irradiation at room temperature. The results show a synergetic effect of Michler's ketone and benzophenone mixed photoinitiators on the water absorbency, and incorporation of bentonite below 10 wt% into the water superabsorbent can slightly increase the water and salt solution absorbencies, and improve water retention, as demonstrated using thermogravimetric analysis and differential scanning calorimetry. Fourier transform infrared spectroscopy allowed the determination of the structure of the bentonite composite superabsorbent. Copyright © 2006 Society of Chemical Industry     

Influence of potassium humate on the swelling properties of a poly(acrylic acid‐co‐acrylamide)/ potassium humate superabsorbent composite

A novel superabsorbent composite, poly(acrylic acid‐co‐acrylamide)/potassium humate (PAA‐AM/KHA), was prepared by aqueous solution polymerization from acrylic acid, acrylamide, and potassium humate (KHA) with N,N′‐methylenebisacrylamide as a crosslinker and potassium peroxydisulfate as an initiator. The effects of incorporated KHA on the water absorbency, swelling rate, and reswelling capability were investigated. The swelling property of PAA‐AM/KHA in various saline solutions was studied systematically. The results show that the comprehensive properties and especially salt‐resistant ability of PAA‐AM/KHA were enhanced. There was a linear relationship between the saturated water absorbency and the minus square root of the ionic strength of the external medium, and the water absorbency of PAA‐AM/KHA in various salt solutions had the following order: NH₄Cl_(aq) = KCl_(aq) = NaCl_(aq) > MgCl_2(aq) > CaCl_2(aq) > AlCl_3(aq) > FeCl_3(aq). Moreover, the polymeric net structure of PAA‐AM/KHA was examined with respect to that of poly(acrylic acid‐co‐acrylamide). The results indicate that the polymeric net of PAA‐AM/KHA was improved by the introduction of a moderate amount of KHA into the superabsorbent composite and made more suitable for agriculture and horticulture applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Preparation of acrylic acid and AMPS cointercalated layered double hydroxide and its application for superabsorbent

This article reports the cointercalation of acrylic acid (AA) and 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) in the interlayer region of Mg₂Al layered double hydroxide (LDH) and the application of this inorganic–organic composite material in the field of water superabsorbent. The monomers of AA and AMPS were cointercalated into galleries of Mg₂Al−LDH (denoted as AA−AMPS/LDH) with various molar ratios by ion‐exchange method, which was confirmed by powder X‐ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), and elemental analysis. The polymer‐based superabsorbent was prepared through in situ free‐radical aqueous copolymerization of AA and AMPS, with AA−AMPS/LDH as additive, N,N′‐methylenebisacrylamide (NMBA) as crosslinker and potassium persulfate (KPS) as initiator. The composition of this poly(AA‐co‐AMPS)/LDH was demonstrated as a good water superabsorbent. The LDH content, water absorbency, thermal stability, and swelling rate of this superabsorbent were also investigated in detail. Results showed that the incorporation of a 5 wt % AA−AMPS/LDH into polymer matrix increased its water absorbency significantly by 27.7% (in water) and by 51.5% (in 0.9 wt % NaCl solution). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of medium pH on the reactivity ratios in acrylamide acrylic acid copolymerization

The copolymerization reactivity ratios of acrylic acid and acrylamide are found at pH 5 and pH 2. Automatic continuous online monitoring of polymerization reactions (ACOMP) has been used for the first time to monitor the synthesis of polyelectrolytic copolymers. The composition drift during the reactions revealed that at pH 5, the acrylamide participates more in the copolymer, and at pH 2, the acrylic acid incorporates in the system at a higher ratio. The copolymerization data were analyzed by a recent error in variables (EVM) type calculation method developed for obtaining the reactivity ratios by on‐line monitoring and gave at pH 5 reactivity ratios r_Aam = 1.88 ± 0.17, r_Aac = 0.80 ± 0.07 and at pH 2 r_Aam = 0.16 ± 0.04, r_Aac = 0.88 ± 0.08. The results show that the reactivity ratios depend strongly on the pH of the medium. The effect of polyelectrolytic interactions on the reactivity ratios is discussed in detail. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 968–974, 2007     

Preparation of superabsorbent composite based on acrylic acid-hydroxypropyl distarch phosphate and clinoptilolite for agricultural applications

Recently, using superabsorbent polymers (SAPs) are considered as a solution for reducing the water consumption particularly in agricultural applications. Presented here is the synthesis of a novel biocompatible SAP, utilizing for reducing the water consumption particularly in agricultural applications via graft copolymerization of hydroxypropyl distarch phosphate (HDP) based on tapioca starch with acrylic acid (AA), loading with clinoptilolite zeolites. A two-level factorial design of experiments, investigating the effect of the SAP composition on the water absorbency exhibited that the optimum SAP has the maximum water absorbencies of 1075 and 67 g g⁻¹ in distilled water and 0.9 wt % NaCl solution, respectively. The chemical structure of the best superabsorbent was characterized using Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy analyses. The results revealed that AA was successfully grafted onto HDP and surface morphology of the superabsorbent was improved with incorporated clinoptilolite zeolites. In addition, the results of water absorption in different soil textures showed that within a first week after irrigation, the soil texture with 100% sand has the maximum water retention (69.6 g more than its control sample), as well as that with 50% sand, loses the absorbed moisture 49 days later than its control sample. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47365.     

Preparation of a starch‐graft‐acrylamide/kaolinite superabsorbent composite and the influence of the hydrophilic group on its water absorbency

A novel starch‐graft‐acrylamide/kaolinite superabsorbent composite with water absorbency 4000 times (g ) was synthesized by a graft copolymerization reaction among acrylamide, potato starch and kaolinite ultrafine powder, followed by saponification with NaOH. The influence of the hydrophilic group on water absorbency was investigated. It was found that the combined absorbent effect of —CONH₂, —COONa and —COOH groups was superior to that of a single group, and the composite with the molar ratio of 8:6:3 for the —CONH₂, —COONa and —COOH groups exhibits the highest water‐absorbent ability. Copyright © 2003 Society of Chemical Industry     

Radiation‐induced graft copolymerization of acrylic acid/acrylonitrile onto LDPE and PET films and its biodegradability

Graft copolymerization of acrylic acid/acrylonitrile (AAc/AN) comonomer onto low‐density poly(ethylene) (LDPE) and poly(ethylene terephthalate) (PET) films using direct radiation grafting technique has been investigated. The effect of different reaction conditions on the grafting yield was studied. The structure of the grafted films at different compositions was characterized by FTIR, TGA, SEM, and XRD. Biodegradation of grafted LDPE and PET was investigated by burial method in two types of Egyptian soils (agricultural and desert soils). The bacteria responsible for biodegradation were isolated and characterized, and the capacities for the growth on these polymers as substrates were compared. The isolates from agricultural soil were characterized as Pseudomonas, Alcaligenes, Bacillus, Proteus, and Enterobacter, whereas the isolates from desert soil were characterized as Alcaligenes, Bacillus, and Pseudomonas. The highest degradation rate was found to be achieved using agricultural soil. It is found that the isolated strains belonging to the genus Pseudomonas were mainly responsible for the degradation of both polymers. It has also been found that the increase of AAc ratio in the composition increases the hydrophilicity of the films and the degradation rate. PET polymer is generally found to be more resistant to the biodegradation than LDPE in the two types of soils tested. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and characterization of a new coagulant based on the sago starch biopolymer and its application in water turbidity removal

A new organic coagulant, sago starch (SS)‐graft‐polyacrylamide (PAm), was prepared by the ceric‐ion‐induced redox polymerization of acrylamide (Am) onto SS at room temperature. The effects of the variation of the concentration of Am and the initiator on the percentages of yield and total conversion were investigated. The chemical composition, viscosity, and side‐chain‐average molecular weight of the obtained graft copolymers were determined. The newly obtained coagulant was tested for the treatment of the turbidity of water. The SS‐g‐PAm coagulants were found to achieve water turbidity removal up to 96.6%. The results of this study suggest that SS‐g‐PAm copolymer is a potential coagulant for reducing turbidity during water treatment. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Grafting of glycidyl methacrylate onto high‐density polyethylene with reaction time in the batch mixer

The melt grafting of glycidyl methacrylate (GMA) onto high‐density polyethylene (HDPE) in the presence of free radical initiators was investigated in the batch mixer. The graft content was determined with the titration and FTIR spectroscopy. The graft content increased with the increase of peroxide and initially introduced GMA concentration. Increase of the grafted GMA content resulted in decrease of the melt index. Interestingly, there was a sudden drop of GMA grafting content with the reaction time. It is assumed that depolymerization of GMA have taken place over the ceiling temperature. The crystallinity of the prepared glycidyl methacrylate grafted high density polyethylene (HDPE‐g‐GMA) was determined by the measurement of the heat of fusion. GMA grafted site acted as defect and crystallinity of the HDPE‐g‐GMA decreased with the increase of grafting reaction. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

K2S2O8-Na2S2O3引发淀粉与丙烯酸接枝产物吸水性能的主要影响因素

以玉米淀粉和丙烯酸为主要原料,采用溶液聚合的方法,制备了淀粉与丙烯酸接枝共聚物,用FTIR等方法对共聚产物结构进行了表征。研究了在过硫酸钾-硫代硫酸钠组成的氧化-还原引发体系中,引发剂、交联剂不同浓度及丙烯酸不同中和度等因素对共聚产物吸水性能的影响。实验结果表明采用K2S2O8-Na2S2O3引发体系,通过控制引发剂、交联剂浓度,接枝产物吸去离子水可达920 g/g;采用玉米粉代替玉米淀粉与丙烯酸接枝共聚,产物吸去离子水可达870 g/g;这些实验结果进一步提高了吸水树脂的吸水能力。     

Cation exchange membranes by radiation-induced graft copolymerization of styrene onto PFA copolymer films. I. Preparation and characterization of the graft copolymer

PFA-g-polystyrene graft copolymers were prepared by simultaneous radiation-induced graft copolymerization of styrene onto poly(tetrafluoroethylene-co-perfluorovinyl ether) (PFA) films. The effects of grafting conditions such as monomer concentration, dose, and dose rate were investigated. Three solvents, i.e., methanol, benzene, and dichloromethane, were used as diluents in this grafting system. Of the three solvents employed, dichloromethane was found to greatly enhance the grafting process, and the degree of grafting increased with the increase of monomer concentration until it reached its highest value at a styrene concentration of 60 (vol %). The dependence of the initial rate of grafting on the monomer concentration was found to be of the order of 1.2. The degree of grafting was found to increase with the increase in irradiation dose, while it considerably decreased with the increase in dose rate. The formation of graft copolymers was confirmed by FTIR analysis. The structural investigation by X-ray diffraction (XRD) shows that the degree of crystallinity content of such graft copolymers decreases with the increase in grafting, and consequently, the mechanical properties of the graft copolymers were influenced to some extent. Both tensile strength and elongation percent decreased with the increase in the degree of grafting. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2095–2102, 1999     

Study on superabsorbent composites. XVIII. Preparation,characterization, and property evaluation of poly(acrylic acid‐co‐acrylamide)/organomontmorillonite/sodium humate superabsorbent composites

A series of novel multifunctional poly (acrylic acid‐co‐acrylamide) (PAA‐AM)/organomontmorillonite (O‐MMT)/sodium humate (SH) superabsorbent composites were synthesized by the graft copolymerization reaction of partially neutralized acrylic acid and acrylamide on O‐MMT micropowder and SH with N,N′‐methylene bisacrylamide as a crosslinker and ammonium persulfate as an initiator in an aqueous solution. The superabsorbent composites were characterized by means of Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The effect of the relative weight ratio of SH to O‐MMT on the water absorbency was studied, and the results indicated that the best water absorbency of 591 g/g in distilled water was obtained when an O‐MMT content of 20 wt % and an SH content of 30 wt % were incorporated. The superabsorbent composite possessed a good capacity for water retention; even after 30 days, 24.4 wt % of water could still be saved by the sand soil containing 1.0 wt % superabsorbent composite. The results from this study show that the water absorbency of a superabsorbent composite is improved by the simultaneous introduction of O‐MMT and SH into a PAA‐AM network in comparison with the incorporation of only O‐MMT or SH. Also, in comparison with PAA‐AM/MMT/SH, an appropriate amount of O‐MMT can benefit the developed composites with respect to their water absorbency, salt resistance, and capacity for water retention in sand soil. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Dispersion copolymerization of acrylamide with acrylic acid in an aqueous solution of ammonium sulfate: Synthesis and characterization

Dispersion copolymerization of acrylamide with acrylic acid in an aqueous solution of ammonium sulfate using poly(2‐acrylamido‐2‐methylpropanesulfonic acid sodium) as the stabilizer and ammonium persulfate (APS) as the initiator was investigated. The influence of initiator concentration, stabilizer concentration, ammonium sulfate concentration, chain‐transfer agent concentration, and polymerization temperature on the copolymerization was discussed. The results showed that varying the ammonium sulfate concentration could affect the particle size and the intrinsic viscosity of the copolymer significantly. With increasing the stabilizer concentration, the particle size of the copolymer decreased first, and then increased, meanwhile the intrinsic viscosity of the copolymer decreased. The increase of initiator concentration, chain‐transfer agent concentration, and polymerization temperature resulted in the increase in the particle size. Polydisperse spherical particles were formed in the system, and the kinetics for the dispersion copolymerization were discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3685–3690, 2006     

Radiation‐induced graft polymerization of glycidyl methacrylate onto PE/PP nonwoven fabric and its modification toward enhanced amidoximation

A nonwoven fabric made of polypropylene coated by polyethylene was used as the trunk polymer in the preparation of a highly efficient new adsorbent. Metal ion uptake capacity has been aimed to be increased by introducing double amidoxime groups per repeating unit of the chains grafted to trunk polymer. The base polymer was irradiated by electron beams with a dose of 200 kGy under N₂ atmosphere and glycidyl methacrylate (GMA) was grafted onto irradiated nonwoven fabric. Grafting conditions were optimized, and GMA‐grafted polymer was modified with 3,3′‐iminodipropionitrile in ethanol at 80°C. GMA grafting (150%) was determined to be the optimum degree given that higher extent of grafting rendered the materials brittle. Pendant nitrile groups were then amidoximated by using 6% hydroxylamine in methanol–water mixture (1 : 1). The all‐polymeric structures were characterized by using FTIR, SEM, and thermal analysis methods, confirming the grafting, modification, and amidoximation stages gravimetrically, spectroscopically, and visually. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007