The Interaction Between Surfactants and 2‐Hydroxy‐3‐(N,N‐dimethyl‐N‐dodecylammonium)‐propyloxy Starches

The phase behavior of temperature‐responsive hydrophobically modified starches and the interaction between oxidized potato amylose and hydrophobically modified potato amylopectin have been investigated by rheology, turbidity measurements and differential scanning calorimetry. When oxidized amylose was mixed with hydrophobically modified amylopectin, a viscosity peak was observed, indicative of a guest‐host interaction between the oxidized amylose and the hydrophobically modified amylopectin. A series of oxidized and hydrophobically modified potato starches were investigated in the presence of an anionic and cationic surfactant. A coil‐helix transition of the investigated starches was observed in the presence of surfactant, with the exception of a cationic surfactant combined with a hydrophobically modified zwitterionic starch of high positive net charge. The destabilizing mechanism (the phase separation) of the hydrophobically modified starches was studied as well as the difference in stabilizing capacity between the investigated cationic and anionic surfactants.     

Determination of the mass‐specific distribution of the substituents in cationic starch derivatives

The mass‐specific charge distribution in molar mass fractions of cationic starch derivatives was investigated. The molar mass fractions were produced by semi‐preparative SEC (SP‐SEC). The derivatives were cut into an amylopectin‐rich fraction F1, an intermediate fraction F2, containing low molar mass amylopectin and high molar mass amylose, and an amylose‐rich fraction F3. The weight‐average molar mass (M_w) and molar mass distribution (MMD) of the fractions were determined by SEC with multi‐angle laser light scattering (SEC‐MALLS). The mass‐specific charge of each fraction was calculated from the consumption of anionic titrant solution using polyelectrolyte titration (PET) in combination with particle charge detection (PCD). The difference in substituent distribution between the fractions was tested by the Student's t‐test. The weight‐average molar mass of the starch derivatives was not dependent on the degree of substitution (DS) or the derivatization process. Depending on the DS value or derivatization process, different substituent distributions were observed. The results for the mass‐specific charge distribution in different molar mass fractions of cationic starch derivatives with graded DS between 0.015 and 0.130 from the slurry process were discussed. The heterogeneity of substituent distribution decreased with increasing DS of the starch derivative. This was the case for samples from both the slurry and semi‐dry processes. The heterogeneity of derivatization was highest for low DS samples up to DS 0.03, with the amylopectin‐rich fraction incorporating more charges than the amylose‐rich fraction. This was more pronounced for the sample from the slurry process than from the semi‐dry process.     

Electrification of antistatic-treated polymeric surface

Nylon and polypropylene surfaces were treated with three different finishes (nonionic, cationic, and anionic) at four different solution concentrations (weight percentage of active finish to solution), 0.025%, 0.05%, 0.075%, and 0.1%. Contact electrification tests showed that charge accumulated on polypropylene decreased as the concentration of nonionic and anionic solutions increased, and charge could be controlled when the concentration reached 0.1%. The same effect was realized when the concentration of the cationic solution was only 0.025%. No contact charging was observed on nylon after treating with any solutions. Rubbing electrification (tribo‐charging) of nylon treated with the nonionic solution showed that charge decreased as the solution concentration increased, and no charge was observed as the solution concentration reached 0.1%. Furthermore, no tribo‐charging of nylon was observed at any level of the cationic or anionic agents applied to the surface.     

聚二烯丙基二甲基氯化铵与木素磺酸钠的复合作用

利用电荷滴定、透光度和粒度测定研究了聚二烯丙基二甲基氯化铵与木素磺酸钠在水介质中的复合作用。发现,两种分子量的聚二烯丙基二甲基氯化铵与木素磺酸钠的等电点复合物具有相同的阴阳离子聚电解质比例,而且加入顺序对等电点的影响不大。此外,聚二烯丙基二甲基氯化铵与木素磺酸钠的加入顺序对复合物的透光度影响很大,同时对粒度也有一定的影响。     

A comparative study on viscosity behavior of water‐soluble chemically modified guar gum derivatives with different functional lateral groups

A comparative study was carried out on the viscosity behavior of three new water‐soluble chemically modified guar gum derivatives with different functional lateral groups, including O‐carboxymethyl‐O‐hydroxypropyl guar gum (CMHPG), with anionic character, O‐2‐hydroxy‐3‐(trimethylammonio)propyl guar gum (HTPG), with cationic character, and O‐carboxymethyl‐O‐2‐hydroxy‐3‐(trimethylammonio)propyl guar (CMHTPG), with amphoteric character. It was found that the shear rate, concentration, temperature, added salt and surfactant affected the viscosity properties of these new guar gum derivatives in aqueous solutions. Regardless of the functional lateral groups, all sample solutions behaved as non‐Newtonian shear‐thinning fluids, and their viscosity increased with the increase in their concentration but decreased with the increase in temperature. Aqueous CMHTPG solution had the strongest shear‐thinning property, and aqueous CMHPG solution investigated had the greatest viscous flow activation energy. In contrast to cationic HTPG or anionic CMHPG, amphoteric CMHTPG had an enhanced viscosity property in aqueous salt solutions, exhibiting an unusual anti‐polyelectrolyte viscosity behavior. The addition of sodium dodecylsulfate was found to result in a decrease in the viscosity of aqueous HTPG solution and an increase in the viscosity of aqueous CMHPG solution or CMHTPG solution. Copyright © 2005 Society of Chemical Industry     

n-SiO2/BGF和PEi-BGF/SiO2两类复合磨粒及抛光液对硅的抛光性能影响

以苯代三聚氰胺甲醛(BGF)微球为内核,用阳离子型聚电解质PDADMAC、阴离子型聚电解质PSS为表面改性剂,利用静电层层自组装技术,制备出不同包覆结构的n-SiO2/BGF和PEi-BGF/SiO2复合磨粒。利用TEM表征两类复合磨粒的吸附情况,并与传统单一SiO2磨粒抛光液、BGF+SiO2混合磨粒抛光液进行实验比较。通过聚合物表面的交替吸附层数、游离磨粒浓度对比两种复合磨粒抛光液对抛光的影响。抛光试验表明,复合磨粒抛光液的材料去除能力明显优于单一磨粒抛光液和混合磨粒抛光液;在两类复合磨粒抛光液对比中,当SiO2磨粒质量分数为5%时,3-SiO2/BGF和PE5-BGF/SiO2复合磨粒抛光液材料去除率达到最大值,分别为369 nm/min和361 nm/min。     

Interaction of cationic starch derivatives and cellulose fibres in the wet end and its correlation to paper strength with a statistical evaluation

The adsorption onto a softwood pulp of cationic modified starches with a degree of substitution (DS) ranging from 0.015 to 0.130 and native potato starch was investigated using a method based on size exclusion chromatography‐multi angle laser light scattering (SEC‐MALLS). This technique provides information about the amount and molecular composition of the adsorbed starch product such as the AP–AM‐ratio, the average MW and molar mass distribution. Factors influencing adsorption, like the electrolyte content in the suspension and the initial starch polysaccharide concentration, were investigated. Furthermore, hand sheets were made and the resulting mechanical paper strength was tested. Results were analysed statistically using analysis of variance. Representative results were discussed in detail. In general, low‐substituted cationic starch (DS 0.030) exhibited a higher degree of adsorption and resulted in high paper strength when there was a low electrolyte content in the starch–pulp‐suspension. However, high amounts of electrolytes impeded electrostatic interaction of the charged groups of the starch polysaccharides and cellulose fibre due to partial screening and therefore strongly limited adsorption. This resulted in lowered mechanical paper strength. The water quality of the suspensions had little impact on the polyelectrolyte adsorption of the highly substituted cationic starch (DS 0.100). However, paper strength was markedly higher in the case of starch adsorption where there was a high ionic content and when both starch polysaccharides–AP and AM– were adsorbed. The initial starch concentration determined starch adsorption both quantitatively and qualitatively and subsequently paper strength as well. The relation between adsorption behaviour and paper strength was discussed, particularly in the case of 6% initial starch concentration. In deionised water (DW), the low‐substituted starch (DS 0.03) adsorbed onto the pulp to a greater extent with an AP–AM‐ratio similar to that of the initial starch. Moreover, this achieved the best strength properties in contrast to 36 dGH, where less starch adsorbed and that being almost exclusively AP. In water with 36 dGH, the highly substituted starch (DS 0.100) with both the AP and AM was absorbed and this resulted in higher paper strength. In contrast, AM was almost exclusively adsorbed in DW. Increasing the initial starch concentration increased the amount adsorbed while subsequently changing the AP–AM‐ratio towards increased AM adsorption and decreased AP adsorption in the case of DS 0.100 in DW. Exclusive adsorption of AM markedly lowered the development of the paper strength.     

Evaluation of membrane fouling for in-line filtration of oil sands process-affected water: the effects of pretreatment conditions

Membrane filtration is an effective reclamation option for oil sands process-affected water (OSPW). However, fresh OSPWs contain suspended solids and inorganic constituents in suspended and dissolved forms that can severely foul membranes. Pretreatment of OSPW with coagulation-flocculation (CF) was investigated to determine the effects of different coagulant aids (anionic, cationic, and nonionic polymers) on membrane surface properties and fouling. Our results showed that CF pretreatment effectively enhanced nanofiltration (NF) and reverse osmosis (RO) membrane permeate flux and salt rejection ratio through reducing membrane fouling. It was shown that coagulants and coagulant aids applied to OSPW feedwater can affect membrane physicochemical properties (surface hydrophilicity, zeta potential, and morphology), membrane performance, and the fouling indexes. Membrane rejection of ionic species increased significantly with the inclusion of an anionic coagulant aid and slightly with a cationic coagulant aid. Among three coagulant aids tested, anionic coagulant aids led to the most enhanced membrane performance through increasing membrane surface negativity and decreasing the formation of a fouling layer. Conversely, although cationic coagulant aids were the most effective in reducing OSPW turbidity, the application of cationic coagulant aids promoted the adsorption of foulants on membrane surfaces.     

基于环糊精衍生物的新型双元絮凝/络合体系的研究

本文研究了阳离子改性环糊精和环糊精星形聚合物两种环糊精衍生物与阴离子聚丙烯酰胺共聚物组成的双元絮凝／络合体系对高岭土悬浊液的絮凝作用及其影响因素，同时研究了两种双元体系对甲苯的络合去除作用。研究表明，两种双元絮凝／络合体系同时具备絮凝和吸附功能，都对高岭土悬浊液具有良好的絮凝作用，但环糊精星形聚合物双元体系在用量极低的条件下就可以达到很高的絮凝效率。环糊精星形聚合物对甲苯的去除作用远大于阳离子改性环糊精，两种双元体系组分的加入顺序对甲苯的去除效果影响不大。由于环糊精星形聚合物具有独特的星形臂结构和较高的电荷密度，使其与阴离子组分间的静电相互作用增强，从而极大地促进了絮凝和去除作用。     

淀粉/聚胺复合物纸张增强机理初探

研究了淀粉/聚胺复合物、阳离子淀粉及原淀粉在纸浆上的吸附类型,测定了淀粉/聚胺混合糊液及单一组分的黏度,探讨了淀粉/聚胺复合物在不同浆种纸张中的作用效果。结果表明,淀粉与聚胺形成了复合物,该复合物对再生浆的作用效果与阳离子淀粉相当,具有明显的增强作用。淀粉/聚胺复合物用量为1.5%时,可使纸板的裂断长增加22.6%,纤维留着增加率提高了6.8%。淀粉/聚胺复合物在纸浆纤维上的吸附为化学吸附和物理吸附共同作用的结果,与阳离子淀粉的吸附相似。     

Digestibility and Pasting Properties of Rice Starch Heat‐Moisture Treated at the Melting Temperature (Tm )

Non‐waxy and waxy rice starches adjusted to 20% moisture (wet based, w.b.) were heated in a differential scanning calorimeter to determine the optimum parameters for producing slowly digestible starch (SDS). Starches heated to the temperature of melting (T_m) and held for 60 min in the calorimeter showed a slow digestibility compared to unheated samples. Digestibility decreased by 25 and 10%, respectively, for non‐waxy and waxy rice starches relative to non‐treated starches. Heat‐moisture treatment of waxy corn, non‐waxy corn and wheat starches at the T_m determined for non‐waxy rice starch did not result in significant decreases in digestibility. For waxy rice starches heat‐treated in microwave or conventional ovens at the T_m , there were slight but significant increases in digestibility of the treated starches compared to non‐treated starches at all incubation times. Digestibility was higher for starches heated for 30 min than for 60 min. Non‐waxy rice starches did not show any significant changes in digestibility. Heat‐moisture treatment at the T_m and the holding time of sample at that temperature in a differential scanning calorimeter were found to be significant to the formation of slowly digestible heat‐moisture treated starch.     

阳离子松香型表面活性剂的合成与性能研究

以松香为原料制备了阳离子松香型表面活性剂,测定了其电荷性能和物理性能.结果表明制备的阳离子松香型表面活性剂具有高电荷密度,水溶性好,且与阴离子表面活性剂有很好相容性,是一种有开发潜力的新型表面活性剂.在中间体制备过程中叔胺的反应速度和时间是决定表面活性剂是否溶于水的关键因素.     

The effect of modified starches on the adsorption of cigarette mainstream smoke composition

In this work modified starches such as porous starch (PS) and cross‐linked phosphorylated porous starch (PPS) were used as tobacco filter to investigate their adsorption efficiency on the tar, ammonia (NH₃), hydrocyanic acid (HCN), crotonaldehyde, and total particulate matter (TPM) in mainstream cigarette smoke. The pore properties and structural stability of the modified starches have been evaluated and the adsorption relationship between the modified starches and the main toxicants in tobacco smoke has also been established. Analytes of mainstream smoke from experimental cigarettes show reductions in yields of some measured constituents in mainstream cigarette smoke, such as tar, HCN, NH₃, crotonaldehyde, and TPM. The largest reductions are for NH₃ levels, up to 35.93% in one case, observed from the tobacco filter containing PPS. The largest reductions in mainstream yields of HCN (13.04%) and crotonaldehyde (31.06%) smoke toxicants were also observed. These results indicate that reducing exposure to some smoke toxicants is possible using the modified starches such as PS and PPS as tobacco filter.     

阴离子垃圾捕集剂在双胶纸中的应用

介绍了一种高阳电荷密度的阴离子垃圾捕集剂PTF用在双胶纸中对纸张性质的影响,尤其是对施胶效果、留着和强度等的影响,并与其它类型的阴离子垃圾捕捉剂如硫酸铝、聚合氯化铝和阳离子淀粉的效果作了比较.通过应用分析,在浆料中添加少量PTF即对施胶效果有很明显改善,且与其他化学助剂有很好的协同作用.     

Characteristics of pores in native and hydrolyzed starch granules

Low‐temperature nitrogen adsorption and mercury porosimetry were applied for analyzing effect of α‐amylolysis upon the porosity of granules of native corn, wheat, rice, and potato starches. Specific surface area (S_BET), porosity, pore size distribution, total pore area, and mean pore radius were determined for native and digested granules. It was found that native starch granules are macroporous materials with a small participation of mesopores. In the case of native starches, the highest value of S_BET was obtained for rice starch (1.27 m²/g) and the lowest – for potato starch (0.14 m²/g). Pore size distribution curves obtained by nitrogen adsorption showed peaks in the range of diameters 2–3 nm (for all starches) and 100–200 nm (for corn and rice starches). After 60 min of enzyme action, surface area of all starches doubled in comparison to native ones. Arising of the new pores was also noted. The results of mercury porosimetry measurements showed that rice starch had the highest total area of pores and porosity but the lowest mean pore radius among all native starches. The pore size distribution curves for all starches exhibited solely one peak corresponding to the dominant group of pores of the radii in the range 0.5–8 µm, dependent on the starch source. There were also much smaller peaks situated within the range of 3–30 µm. After α‐amylolysis of corn and rice starches, the average radius of the dominant group of pores diminished. No substantial changes in the pore radii could be noted for potato starch.     

Effects of Heating,Vacuum Drying and Steeping on Gelatinization Properties and Dynamic Viscoelasticity of Various Starches

Starches having A‐ and B‐type X‐ray diffraction patterns (A‐ and B‐type starches) were modified by heating at 120 °C for 2 h (HT), vacuum drying at room temperature for 20 h (VD) and steeping at 50 °C for 20 h (ST). The properties of starches were compared using differential scanning calorimetry (DSC) and dynamic viscoelasticity behavior during heat processing (G' behavior). As observed by DSC, HT rarely changed the gelatinization properties for A‐type starches, but decreased the gelatinization temperatures and enthalpies (ΔH) for B‐type starches. A shift of the X‐ray diffractograms from B‐type to A‐type patterns was not detected after HT. Similar changes in gelatinization properties were observed for B‐type starches after VD. ST increased the gelatinization temperatures and also narrowed the gelatinization temperature range irrespective of crystal type. Both HT and VD decreased the peak temperature (T_p) in G' behavior and increased the peak G' value for B‐type starches. ST increased T_p and also decreased the peak G' value irrespective of starch crystal type. G' values after reaching T_p — which indicate the viscoelasticity of the swollen starch granules without breakdown — showed significant increases only for B‐type starches after HT.     

Preparation and Application of Chitosan-based Polyelectrolyte Complex Materials: An Overview

Chitosan, a renewable, non-toxic, and natural cationic polyelectrolyte, can be combined with many anionic polyelectrolytes (such as sodium alginate, hyaluronic acid, xylan, and gelatin) via electrostatic forces to form chitosan-based polyelectrolyte composites under certain conditions. This review summarizes various methods of preparing chitosan-based polyelectrolyte composites and analyzes their applications in clinical medicine and agriculture, as well as pharmaceutical, tissue, food, environmental, and textile engineering fields. The future development direction and potential of chitosan-based polyelectrolytes are also discussed.     

Polypyrrole-coated cotton fabrics used for removal of methylene blue from aqueous solution

PPy-coated cotton fabric was prepared in situ chemical polymerization using blends of anionic and cationic surfactants as soft template and investigated as adsorbent to remove dyes in the printing and dyeing wastewater. The PPy-coated fabric was characterized by scanning electronic microscopy and fourier transform infrared spectrum. It was found that the fiber and fabric surfaces were coated by PPy nanoparticles with diameters less than 100 nm which were quite loose and well formed as a three-dimensional network. Dye adsorption experiments demonstrated that the PPy-coated fabric could effectively remove MB dye and the decoloration capacity of MB solution could reach up to 95.6%. Factors influencing the adsorption of MB, e.g. ionic strength, solution pH, contact time, and adsorption mass, were systematically investigated. The adsorption capacity for MB dye increased gradually as its initial concentration increased. The batch experimental results suggested that the PPy-coated fabric could be used as an efficient sorbent to remove dyes in textile effluents.     

Sorption of anionic metsulfuron-methyl and cationic difenzoquat on peat and soil as affected by copper

The effect of cationic copper (Cu2+) on the sorption of anionic metsulfuron-methyl (Me) and cationic difenzoquat (DZ) to peat and soil was studied using a batch equilibration method. The results showed that Cu2+ increased the sorption of Me but diminished the sorption of DZ. The adsorption of Cu2+ on the surface of peat and soil neutralizes the negative charge, making the zeta potential (zeta) of peat and soil less negative, consequently decreasing the repulsion between the surface of peat or soil and Me and increasing the sorption of Me. Cu2+ may additionally form Cu-Me complexes in aqueous solution, which was preferentially sorbed to peat and soil over the anionic Me. In contrast, the decreased negative surface charge of soil and peat does not favor the sorption of cationic DZ. Fourier transform infrared showed that DZ may be sorbed through interaction with -OH or -COOH groups of peat and soil and that surface complexes of Cu2+ may form through these groups. A competitive sorption between Cu2t and DZ for the same sorption sites is indicated, leading to mutual sorption inhibition of both cations.