Preparation of Cationic Starch by Electromagnetic Dry Process (EMDP)

Introduction Cationic starches are a series of products of which various sorts with different properties and usages can all be produced via cationic reactions by using different types of etherification agents under different conditions. As an additive and strengthening agent,

STDUY ON RETENTION AND DRAINAGE PROPERTIES OF THE HIGH SUBSTITUTED DEGREE CATIONIC STARCH

This paper deals with the retention and drainage properties of the high substituted degree cationic starch (HCS) prepared by half-dry process. The experiments show that HCS has remarkable effects on filler retention and drainage in papermaking industry. With the degree of substitution (DS) of HCS increasing, the effects on filler retention and drainage increase. When the DS of HCS is 0.509 and the dosage is 0.08%, the freeness decreases about 12oSR and the filler retention is 79.82%.

APPLICATION OF CATIONIC STARCH BY DRY-PROCESS AS ANIONIC CHARGE NEUTRALIZING AGENTS TO IMPROVE FILLER RETENTION

This paper deals with the preparation of cationic starch with high degree of substitute by dry-process. The corn starch and the alkali catalyst are mixed in the mixer, then added the cationic etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride). The reacting time is for 5 hours at the temperature of 70℃. The cationic starch with high degree of substitution is used as anionic charge neutralizing agents to improve filler retention in wet-end section of papermaking machine.

Flotation of low-grade bauxite using organosilicon cationic collector and starch depressant

The flotation of diaspore and three kinds of silicate minerals, including kaolinite, illite and pyrophyllite, using an organosilicon cationic surfactant (TAS101) as collector and starch as depressant was investigated. The results show that both diaspore and aluminosilicate minerals float readily with organosilicon cationic collector TAS101 at pH values of 4 to 10. Starch has a strong depression effect for diaspore in the alkaline pH region but has little influence on the flotation of aluminosilicate minerals. It is possible to separate diaspore from aluminosilicate minerals using the organosilicon cationic collector and starch depressant. Further studies of bauxite ore flotation were also conducted, and the reverse flotation separation process was adopted. The concentrates with the mass ratio of Al2O3 to SiO2 of 9.58 and Al2O3 recovery of 83.34% are obtained from natural bauxite ore with the mass ratio of Al2O3 to SiO2 of 6.1 at pH value of 11 using the organosilicon cationic collector and starch depressant.

Efficient removal of algae and turbidity from water by a composite coagulant composed of a cationic starch and attapulgite

Algae and suspended colloidal particles produced high turbidity in water,weakened water purification,and threatened the safety of the water supply.In this study,a series of composite coagulants(atp-st-CTA)composed of a cationic starch(st-CTA)and attapulgite(ATP)with different fed mass ratios were fabricated by a simple method to coagulate kaolin suspension with initial turbidity of 80.0 NTU and Chlorella suspension with 0.25 mg/L of chlorophyll a(chla),respectively.Fourier transform infrared spectroscopy and scanning electron microscopy investigated the structural characteristics of atp-st-CTA.The maximum turbidity and chla removal rates of atp-st-CTA were 92.2%and 100.0%,respectively,at natural pH conditions.The effects of the fed mass ratio of st-CTA to ATP in the composites,dose,pH,and coexisting humic acid on the coagulation performance of atp-st-CTA were comprehensively investigated.Based on the apparent coagulation behaviors,the zeta potentials of the supernatants after coagulation,and the flocs properties,the coagulation mechanisms of atp-st-CTA were discussed in detail.The complete charge neutralization due to st-CTA and the enhanced sedimentation by ATP synergistically removed turbidity and algae from the water efficiently.In short,atp-st-CTA as a talented material has a notable prospect in applications of water treatment owing to its advantages of environmental friendliness,low cost,and high efficiency.

Thixotropy of Aqueous Suspensions Containing Mg-AI Hydrotalcite-like Compound and Low-substituted Cationic Starch： Comparison between Oscillatory Shear and Thixotropic Loop Measurements

The rheological properties of aqueous suspensions consisting of positively charged aluminum magnesium hydrotalcite-like compound （HTlc） and low-substituted cationic starch （LCS） were investigated. Special emphasis was placed on the thixotropic phenomenon. Thixotropic behavior was investigated by two thixotropic methods： thixotropic loop and oscillatory shear measurements. LCS molecules could be adsorbed onto HTlc particles due to the hydrogen bonding between ether groups or hydroxyl groups of LCS and hydroxyl groups of HTlc. The elastic dynamic response of the HTlc/LCS suspension increased with increasing mass ratio （R） of HTlc and a three-dimensional network structure could be formed in the suspension with higher R value. The thixotropic type of the HTlc/LCS suspension transformed from negative to positive and then to complex thixotropy when R changed from 0 to 0.5. By comparing between the thixotropic results obtained by thixotropic loop and oscillatory shear measurements, it was validated that the thixotropic loop for the suspension showing complex thixotropy had a crossover point.

Effect of algal flocculation on dissolved organic matters using cationic starch modified soils

Modified soils（MSs） are being increasingly used as geo-engineering materials for the sedimentation removal of cyanobacterial blooms. Cationic starch（CS） has been tested as an effective soil modifier, but little is known about its potential impacts on the treated water.This study investigated dissolved organic matters in the bloom water after algal removal using cationic starch modified soils（CS-MSs）. Results showed that the dissolved organic carbon（DOC） could be decreased by CS-MS flocculation and the use of higher charge density CS yielded a greater DOC reduction. When CS with the charge density of 0.052, 0.102 and0.293 meq/g were used, DOC was decreased from 3.4 to 3.0, 2.3 and 1.7 mg/L, respectively.The excitation–emission matrix fluorescence spectroscopy and UV254 analysis indicated that CS-MS exhibits an ability to remove some soluble organics, which contributed to the DOC reduction. However, the use of low charge density CS posed a potential risk of DOC increase due to the high CS loading for effective algal removal. When CS with the charge density of 0.044 meq/g was used, DOC was increased from 3.4 to 3.9 mg/L. This study suggested, when CS-MS is used for cyanobacterial bloom removal, the content of dissolved organic matters in the treated water can be controlled by optimizing the charge density of CS. For the settled organic matters, other measures（e.g., capping treatments using oxygen loaded materials） should be jointly applied after algal flocculation.

Influence of Inorganic Salts on the Adsorption of Cationically Modified Starch to Fibers

The article is focused on the influence of inorganic salts on the adsorption of cationically modified starch to fibers. Results show that low concentrations of inorganic salts usually affect the process of adsorption in a positive way. Adsorption efficiency at higher concentrations, however, depends on the type of inorganic salts as well as the sequence of adding inorganic salts and starch to paper suspension.

Synthesis, Characterization and Utilization of Starch Hydroxypropyl Sulphate for Cationic Dye Removal

The best conditions for synthesis of starch hydroxypropyl sulphate as per the dry method were firstly established. This was done through a thorough investigation into factors affecting the synthesis including concentrations of both the NaOH catalyst and the 2-hydroxy-3-chloropropyl sulphate along with duration and temperature of the reaction. The resultant newly synthesized 2-hydroxy-3-chloropropyl sulphate was then reacted with starch to obtain starch hydroxypropyl sulphate ultimately. After being characterized by making use of IR spectroscopy analysis and scanning electronic microscope, the starch hydroxypropyl sulphate samples were submitted to evaluation for cationic dye removal using Methylene Blue (MB). Cationic dye removal was studied under a variety of conditions. Factors involved encompass initial dye concentration, duration, sulphur %, pH and adsorbent dose. 100% dye removal could be achieved under certain conditions which were described in the text.

A NEW METHOD TO SYNTHESIZE THE CATIONIC GRAFT STARCH

The cationic graft copolymer was synthesized by reversed phase emulsion copolymerization of starch with diallydimethyl ammoniumlchlorid (DADMAC) and acrylamide(AM). The copolymerization was carried out using (NH4)2S2O8-NH2CONH2 redox as initiator and selecting Span-20 as emulsifier. The effects of emulsifier content in oil phase, volume ratio of oil to water, initiator concentration and mole ratio of DADMAC to AM on the graft copolymerization were discussed. The optimum condition of synthetics was found with the orthogonal test method.

Preparation of Cationic Chitosan-Polyacrylamide Flocculant and Its Properties in Wastewater Treatment

Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide （AM） and methacrylatoethyl trimethyl ammonium chloride （DMC） as raw materials and ceric ammonium nitrate （CAN） as initiator. The flocculation ability of the resulting polymer （PCAD） was studied in waste water treatment experiments. Its properties were determined on the basis of the transmittance of waste water after flocculation. The effects of ehitosan and DMC content on PCAD＇s flocculation ability were studied. Floeculation experiments were also undertaken under various pH conditions. According to the experimental data, the flocculation ability could be improved when chitosan content decreased in the raw material, but the monomer conversion would decrease obviously. When the ehitosan＇s content was more than 65%, AM and DMC groups were less on each chitosan molecule. So PCAD＇s flocculation ability was poor. Similarly, high content of DMC would result in low monomer conversion and high flocculation ability. PCAD molecules with more DMC group had more positive charges. It was favorable to flocculation. However, monomer conversion would decrease with the increase of DMC content. The suitable conditions were that chitosan and DMC contents were 65% and 15-20%, respectively. The experiment data showed that PCAD had good flocculation ability under weak acidic condition. Its ability would be weakened by strong acidic or alkaline condition. The flocculation efficiency was the best at pH of 5.5 when PCAD＇s dosage was 8mg-Lk Compared with cationic polymer （the copolymer of AM and DMC, PAD）, PCAD showed better flocculation ability under acid and neutral conditions, but worse ability under alkaline condition.

Heterogeneous Reactions between Starch and AKD under Solvent-free Conditions

Oxidized starch powder and cationic starch solution were reacted with alkyl ketene dimer(AKD) under heterogeneous conditions at 70℃ for 12 h.The AKD molecules reacted with starch hydroxyl groups to form β-keto ester linkages under the above conditions.The reaction products were separated into CHCl_3-soluble and CHCl_3-insoluble fractions.FT-IR spectroscopy,SEM,Xray diffraction,and TG-DTA analyses of the CHCl_3-insoluble fraction indicated that β-keto ester substituents were introduced to hydroxyl groups on the starch surfaces.The results indicated that hydrogen bonds between the starch molecules were disrupted under heterogeneous conditions upon heating.The activity and accessibility of hydroxyl groups were enhanced,as a result of which β-keto ester bonds were produced between AKD and starch.Based on these results,we speculate that the β-keto esters which existed in the sheets sized by AKD emulsions were generated by the reaction between AKD and starch.

Studies on a Cationically Modified Quaternary Ammonium Salt of Lignin

A new quaternary ammonium salt monomer was synthesized and a quaternary amination of lignin（ noted as QL）, with the monomer was carried out by grafting copolymerization. The products were characterized by Fourier Transform Infrared spectroscopy（ FTIR）. The experimental results indicate that the yield of the monomer was 99.06%, and the conversion of the monomer and the grafting yield of QL were 93.69% and 185.78%, respectively. The feasibility of QL as the flocculant to be applied in color removal of five artificial dyes, erioehrome black T（dye A）, gongo red（dye B ）, direct fast black G （dye C ）, cuprofix blue green B （dye D ）, and acid black ATT （dye E ） was examined. Results show that OL exhihits the favorable flocculation nerformance and high stability.

Reinforcing Paper Strength by Dual Treatment of a Cationic Water-soluble Polymer and Cellulose Nanofibril

Cellulose nanofibril(CNF)was used as the anionic component of two dual strengthening systems wherein polyamidopolyamine epichlorohydrin resin(PAE)or cationic starch(CS)was used as the cationic component.Their strengthening effects were investigated for lowbasis-weight(30 g/m2)paper composed of a mixture of fully bleached softwood and hardwood pulp in a 4:1 mass ratio.Using the PAE/CNF or CS/CNF dual system,it was generally easier to achieve higher wet and dry tensile strengths of paper compared to the paper using the single PAE or CS system.For example,the paper using the PAE(0.4%)/CNF(0.3%)dual system exhibited 89%higher wet tensile strength than the paper using the single PAE(0.4%)system,and the paper using CS(1.3%)/CNF(0.3%)dual treatment showed 21%higher dry strength than that using the single CS(1.3%)system.However,the PAE/CNF system only showed small improvement in the dry strength of paper(11%higher than that of paper using the single PAE system),so did the CS/NFC system on wet strength improvement(only 17%higher than that of paper using the single CS system).

Starch-g-PAM对被污染的土霉素发酵液絮凝性能的研究

本文用Starch-g-PAM对被污染的土霉素发酵液进行了絮凝、过滤实验,找到了过滤速度和土霉素得率最高的絮凝剂使用条件:净化剂1为0.42％,净化剂2为0.34％,Starch-g-PAM为800ppn,硅藻土为0.2％。

淀粉接枝丙烯酰胺与聚丙烯酰胺对高岭土动态絮凝差异的研究

高岭土等黏土矿的存在是煤泥水沉降效果差的主要原因,目前尚未有关于难沉降煤泥水动态絮凝过程的研究。相较于聚丙烯酰胺(PAM)合成单体的毒性,淀粉接枝丙烯酰胺(SAM)合成的单体可降解性好。为此,以高岭土为研究对象,系统对比了SAM与PAM对高岭土动态絮凝过程的影响。首先,考察了不同SAM与PAM用量下的沉降速度和絮凝效果。随后,通过聚焦光束反射测量(FBRM)和颗粒录影显微镜(PVM)技术研究了高岭土悬浮液在SAM和PAM作用下的不同粒级颗粒数量变化。沉降实验和FBRM-PVM测试结果表明,PAM能够形成更多的+100μm大絮团,使得PAM具有更好的沉降效果;SAM形成的絮团更稳定,对细颗粒的絮凝效果更好。最后,通过FBRM获得的数据,基于Smoluchowski模型计算了PAM和SAM作用下高岭土的絮凝动力学参数,发现PAM作用下的絮凝指数明显高于SAM,同时-30μm和30~60μm颗粒数量的动态变化主导了絮凝动力学中絮团的形成过程。总体而言,PAM可以形成更多的、松散的大絮团,有利于高岭土的快速沉降,但对微细颗粒絮凝效果不佳。相较于PAM,SAM独特的多链立体网状结构,有利于微细颗粒絮凝和形成稳定的絮团,从而避免选煤厂洗水系统中细泥的循环积聚。

高取代度阳离子淀粉基苯丙乳液的合成和应用研究

以苯乙烯(St)、丙烯酸正丁酯(BA)、丙烯酸叔丁酯(tBA)为单体,H2O2-FeSO4为引发体系,高取代度阳离子淀粉(HCS)为乳化剂,开展了苯丙表面施胶剂的无皂乳液聚合。探讨了HCS的用量、分子量(以特性黏度表示)、取代度对乳液聚合的影响,使用多种方法评价了乳液的理化性能与应用性能。所制备得的高取代度阳离子淀粉基苯丙乳液胶粒平均粒径小(126.2 nm)、正电性强(Zeta电位为25.8 mV)、贮存稳定性优良;将其应用在瓦楞原纸上,施胶纸张的Cobb值为21.6 g/m^(2),水滴接触角达121.6°,与低取代度阳离子淀粉基苯丙乳液相比,其应用效果具有明显优势。研究对其能赋予纸张更佳施胶效果的原因也提出了机理性的解释。

阳离子淀粉改性阳离子乳液聚合物及其絮凝性能研究

通过阳离子淀粉对阳离子乳液聚合物功能化改性,研究阳离子淀粉功能改性对阳离子乳液聚合物性能的影响,得到改性阳离子乳液聚合物絮凝剂对再生纸废水和含油污水进行絮凝性能。结果显示,CS投加量为6%,改性阳离子乳液聚合物絮凝剂用量为28 mg/L时,再生纸废水COD去除率达95%,SS去除率达94%;CS改性阳离子乳液聚合物絮凝剂添加量为6 mg/L时,含油污水脱油率为97.78%;并用红外光谱、核磁共振、热重分析和电子显微镜对改性后的阳离子乳液聚合物絮凝剂结构进行了表征,得出阳离子淀粉改性阳离子乳液聚合物性能突出。

体外透皮递送SPE的CMC/CS/Ca^(2+)复合水凝胶及其抗氧化活性研究

像大豆肽(SPE)这样的肽类物质在药物靶向治疗和诊断等方面有着重要作用,但它们难以抵抗胃部极低的pH环境以及离子障碍,因此难以通过口服的方式进行递送。透皮递送系统可避免胃液的障碍,将药物递送到血液中。文中通过冻融循环成功制备了负载SPE的羧甲基纤维素/阳离子淀粉/Ca^(2+)(CMC/CS/Ca^(2+))复合水凝胶,以克服透皮递送过程中皮肤角质层对水溶性SPE渗透的障碍。颗粒电荷分析(PCD)、傅里叶变换红外光谱(FT-IR)以及流变结果表明,CMC、CS及Ca^(2+)之间产生了化学和物理交联作用,形成了稳定的复合水凝胶,且SPE与CS、Ca^(2+)间产生的相互作用使其力学性能可满足透皮递送的要求;扫描电子显微镜(SEM)和比表面积测试(BET)结果表明,这些复合水凝胶内部具有多孔洞的三维网络结构。复合水凝胶的含水率均高于95.63%,在25℃下持续25 min后其保湿率仍在97.34%以上,所有复合水凝胶均在120 min内快速溶胀,在720 min时平衡溶胀分数可达636.23%,说明该复合水凝胶对水具有高度的亲和性,这是SPE透皮递送效率提高的根本原因。体外释放结果表明,SPE从复合水凝胶中的释放为溶胀控释型,且其最大DPPH自由基和ABTS自由基清除率分别可达47.07%和72.16%。3种复合水凝胶中SPE的单位面积累积渗透量分别为0.55、0.70和0.60 mg/cm^(2),其累积渗透百分比分别达到84.13%、92.93%和92.57%。复合水凝胶的外观以及pH值、耐热性、耐寒性均符合QB/T 2872—2017的规定。文中制备的复合水凝胶不仅有望在透皮递送肽及蛋白质类药物上得以应用,在皮肤抗氧化护理方面也具有潜在的应用价值。

阳离子改性淀粉原位除藻试验研究

以阳离子改性淀粉作为絮凝剂,在天津某饮用水源地一蓝藻富集区进行原位处置,对比分析水体在投加淀粉前后pH值、透明度、总氮、总磷、浮游植物丰度及种群结构的变化。结果表明,阳离子改性淀粉能使水体表层藻类迅速絮凝成团下沉,水体透明度显著提升,水中氮磷浓度明显降低。与对照区相比,试验区表层浮游植物的丰度显著下降,前6 d浮游植物去除率为86%~95%,整个试验周期平均去除率为78%,其中原优势种铜绿微囊藻下降最为突出,该絮凝剂对球状藻的去除和控制效果优于丝状藻。