Alkali Tolerance of Concrete Internal Curing Agent Based on Sodium Carboxymethyl Starch

Internal curing agents (ICA) based on super absorbent polymer have poor alkali tolerance and reduce the early strength of concrete.An alkali tolerate internal curing agent (CAA-ICA) was designed and prepared by using sodium carboxymethyl starch (CMS) with high hydrophilicity,acrylic acid (AA) containing anionic carboxylic group and acrylamide (AM) containing non-ionic amide group as the main raw materials.The results show that the ratio of CAA-ICA alkali absorption solution is higher than that existing ICA,which solves the low water absorption ratio of the ICA in alkali environment.The water absorption ratio of CAA-ICA in saturated Ca(OH)_(2) solution is 95.8 g·g^(-1),and the alkali tolerance coefficient is 3.4.The application of CAA-ICA in cement-based materials can increase the internal relative humidity and miniaturize the pore structure.The compressive strength of mortar increases up to 12.95%at 28 d,which provids a solution to overcome the reduction of the early strength.

Effect of degree of substitution of carboxymethyl starch on diaspore depression in reverse flotation

Carboxymethyl starchs（CMS） with low and high degrees of substitution（CMSL and CMSH in short,respectively） were employed as depressants of diaspore in cationic reverse flotation using dodecylamine（DDA） as collector.The effect of degree of substitution of CMS on its depression performance was examined and the interaction mode and behavior were investigated in a comparative manner.Micro-flotation test showed that CMSL exhibited better performance in depressing diaspore than CMSH in a broad pH range.The adsorption of CMS on diaspore was studied by adsorption test,zeta potential measurement,and atomic force microscopy.It was found that CMSH corresponds to lower adsorption amount,thinner adsorption layer,and more negative charge than CMSL,resulting from the more chelating sites brought by the high degree of substitution.The surface tension measurement and DDA adsorption test further revealed that CMSL/DDA system gives a better depressing performance benefiting from the trapping effect by enveloping some DDA molecules inside the loop chains,while CMSH/DDA system is likely considered a quasi-surfactant.

羧甲基淀粉CMS应用研究

介绍一种用于造纸的新型淀粉衍生物———羧甲基淀粉 (CMS) ,进行了浆内添加和表面施胶的试验。CMS可以直接溶于水 ,使用方便 ;浆内添加时有较好的增强、助留效果 ,用于表面施胶可明显提高纸张表面强度。

CMS-Fe^(2+)络合物对降低卷烟烟气部分有害物质的研究

以羧甲基淀粉钠(CMS)为原料,采用配位Fe2+形成新的络合物,并通过正交实验对CMS-Fe2+络合物最佳配比进行了优化,结果表明:在反应体系pH7.0,络合时间3h,硫酸亚铁铵与CMS的质量分数比1.2:1,抗氧化剂添加量50%的条件下,络合物中Fe2+的质量含量为4.06%。通过离子色谱法和氢火焰离子检测器分别对氨和巴豆醛进行标气检测,结果表明,CMS-Fe2+络合物几乎完全能去除氨,降低巴豆醛为16.99%,这为CMS-Fe2+络合物作为滤嘴添加剂选择性吸附烟气中部分有害成分奠定了一定的理论和应用基础。

几种成膜助剂对CCMS/PVA可降解薄膜力学及耐水性能影响的研究

以交联羧甲基淀粉为基料,辅以消泡剂、脱膜剂、疏水剂等成膜助剂,通过流延成膜工艺,制备了淀粉基可降解薄膜,研究了成膜助剂对降解膜耐水性能和力学性能的影响。结果表明,当助剂消泡剂用量为1%,液体石蜡用量为0.8%,PPE用量1.5%时,CCMS/PVA的拉伸强度为40.5Mpa,断裂伸长率为311%,透光率为82%,吸水率最小为3.6%。

影响CCMS与PVA薄膜降解速率的因素研究

以交联羧甲基淀粉为原料,分别加入不同种类成膜助剂,制成几种不同性质的淀粉基可降解薄膜。微生物降解和土埋试验表明,可通过调节CCMS和PVA的配比控制膜的使用寿命,伴随复合交联剂与PPE用量的增多,微生物的生长及繁殖速率逐渐减慢,薄膜的降解速度有所降低。可通过控制复合交联剂和PPE的用量达到人为控制该膜降解时间的目的。

CMS的制备及应用性能研究

用玉米淀粉、氯乙酸和氢氧化钠为原料 ,在乙醇溶剂中反应制备羧甲基淀粉 .考察了反应的影响因素 ,并研究了羧甲基淀粉糊的性能 .

溶液法制备钻井泥浆用的钠羧甲基淀粉(CMS)的试验研究

淀粉是一种多羟基有机高分子化合物。利用相似相溶原理,以甲醇或乙醇为溶剂,溶解淀粉,制成的钠羧甲基淀粉不溶于乙醇,有利于生成物的分离提纯;同时一氯乙酸在醇溶液中的电离度低,对反应的影响较小,有利于反应的进行。此方法具有合成工艺简单,生产效率高,成本低等特点。

CMS-AM共聚物的制备及性能评价

采用自由基聚合法,以羧甲基淀粉(CMS)与丙烯酰胺(AM)为原料,在引发剂的作用下合成了CMS-AM接枝共聚物。通过正交试验设计确定了最佳合成条件,利用傅里叶转换红外光谱(FT-IR)验证最佳合成条件下得到产物的结构,采用旋转黏度计测定了接枝共聚物CMS-AM水溶液的剪切稳定性、对盐的敏感性和温度稳定性。结果表明:红外光谱分析证实,经聚合反应制得了CMS-AM共聚物,在70℃下反应7 h、CMS与AM质量比1:8、引发剂用量0.9%时,CMS-AM接枝共聚物的接枝率可达689%,接枝效率可达94.7%,单体转化率达90.9%。CMS-AM接枝共聚物的抗剪切、抗盐、耐温性良好,可以满足油田压裂液对增稠剂的需求。

P(CMSNa-NaAlg-AA)高吸水树脂制备及其性能研究

以一定比例的羧甲基淀粉钠(CMSNa)、海藻酸钠(Na Alg)为接枝基体,丙烯酸(AA)为单体,过硫酸铵(NPS)为引发剂,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂,采用水溶液聚合法合成高吸水树脂。探讨了不同反应条件对吸水性能的影响,并研究了吸水树脂吸附重金属(Cd2+)的动力学及热力学特性。结果表明,当m(CMSNa):m(Na Alg)=2.5,引发剂用量为单体用量0.3%,交联剂用量为单体用量0.025%,丙烯酸中和度为70%,反应温度为65℃时,吸去离子水及0.9%Na Cl溶液倍率分别为2 308.48 g/g、126.8 g/g。吸水树脂对于镉离子的吸附研究表明,高吸水树脂对于镉离子的吸附在p H值为7时吸附容量最大,为343.44 mg/g,且吸附符合准二级动力学模型及Langmuir吸附等温模型。

以甲醇为溶剂合成高粘度CMS的现状与市场前景

羧甲基淀粉钠(Sodium Carboxymethyl Starch,简称Na-CMS)又称羧甲基淀粉(CMS)或羧甲基淀粉醚,是一种冷水可溶性的阴离子型淀粉衍生物。为了改进以往用少量水和乙醇或是丙醇等混合溶剂醚化产率低、取代度相对较低的问题着手以甲醇为溶剂合成高粘度CMS。然而在发展的同时,也存在一些需要解决的问题,如甲醇对人体的侵害较为严重,大量使用不利于环境保护和人体健康,淀粉及深加工产品综合利用率低、深加工高科技产品少、淀粉转化率低等,缺乏针对性研究成了函待解决的问题。

羧甲基淀粉CMS的应用

阐述了一种用于造纸的新型淀粉衍生物—羧甲基淀粉(CMS),进行了浆内添加的试验.CMS可以直接溶于水,使用方便;浆内添加时有较好的增强和助留效果.

改性淀粉CMS浆料的研究

改性淀粉CMS(羧甲基淀粉)是一种淀粉醚,它是由淀粉与ClCH_2COOH进行醚化作用而成的。CMS属常温溶解型,它所形成的浆液热稳定性及与其它浆料的共混性好,它宜采用低浓高粘的上浆工艺。

Effect of Carboxymethyl Starch as Stabilizer for Increasing the Stability of Warp Sizing Pastes

The influences of carboxymethyl starch used as stabilizer upon the stability of native cornstarchpolyvinyl alcohol blend pastes for warp sizing have been investigated. The effect of the modified starch on the paste stability was evaluated in terms of the initial demixing time and the volume percentage of separated starch. The carboxymethyl starch with a series of different degrees of substitution was prepared in ethanol dispersion by varying the amount of monochloroacetic acid reacted with refined native cornstarch. The paste stability strongly depends on the modification extent and amount of carboxymethyl starch used, and on native starch content in the paste. Increase in the modification extent and/or the amount of the modified starch effectively retards the phase separation and reduces the separation extent of native cornstarch-polyvinyl alcohol blend pastes.Moreover, the mechanism and favorable modification extent of carboxymethyl starch for enhancing paste stability are also investigated and discussed.

Synthesis and Excellent Antibacterial Activity of Ag_(2)O-Loaded Carboxymethyl Starch Nanocomposites

Carboxymethyl starch/silver oxide nanocomposites(CMS-Ag_(2)O NCs)were successfully fabricated by modifying carboxymethyl starch(CMS)with Ag_(2)O obtained from an aqueous AgNO_(3)solution as silver source.Ag_(2)O nanoparticles(NPs)formed on the surface of CMS by ion exchange.Based on SEM images,the diameters of Ag_(2)O NPs were determined to be between 50 and 100 nm.From the XRD spectra of CMS-Ag_(2)O NCs,the new diffraction peaks appeared at 33.88°and 38.08°,which were attributed to the Ag_(2)O NPs.According to the XPS analysis,Ag 3d_(5/2)and Ag 3d_(3/2)peaks in CMS-Ag_(2)O NCs were fitted into two main peaks centered at 367.6 eV and 373.6 eV,which were attributed to Ag^(+).The antibacterial efficiencies of CMS-Ag_(2)O NCs against Escherichia coli,Staphylococcus aureus,Pseudoalteromonas tetraodonis,Micrococcus luteus,and Shewanella putrefaciens were determined to be 99.6%,99.7%,99.4%,99.5%,and 99.6%,respectively.The antibacterial efficiencies of CMS-Ag_(2)O NCs against the bacterial species were all greater than 99%.Therefore,these results indicated that CMS-Ag_(2)O NCs was highly effective as a bactericidal agent against multiple bacterial species.CMS-Ag_(2)O NCs can be further applied to antifouling coating.

Microwave Assisted Synthesis and Evaluation of Cross-Linked Carboxymethylated Sago Starch as Superdisintegrant

The aim of this study was to modify the sago starch and evaluate its efficacy as tablet disintegrant. Cross-linked car-boxymethylated sago starch (CMSS) was synthesized using native sago starch (SS) and monochloroacetic acid (MCA) with sodium hydroxide in microwave radiation environment. FT-IR analysis of the sample confirmed the carboxy-methylation by showing absorption peak at 1607.2 cm-1. CMSS with degree of substitution (DS) of 0.31 was formed and, it was further evaluated as disintegrant in Ondasetron based tablets. The results revealed that CMSS could be used as disintegrant in tablet formulation in concentration dependant manner.

Investigation on Mechanical Properties of CMSLDS/Acrylate Copolymeric Blending Films for Warp Sizing

Carboxymethyl starch with lower degree of substitution was, blended with acrylate copolymer for revealing the relation between mechanical properties and chemical structure of blending film. Effects of carboxymethylation of starch, acrylate constituent units of acrylate copolymers, and copolymer content of the film on the properties were investigated. The mechanical properties were evaluated in terms of tensile strength, breaking elongation, abrasion resistance, and flex-fatigue resistance. Film morphology was examined with X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and atomic force microscope （AFM）. It was found that the properties depended on the degree of substitution of carboxymethyl starch, chemical structure of acrylate units, and content of acrylate copolymer. Phase-separation of the two ingredients occurred within film matrix and the separation was decreased after starch carboxymethylation. Breaking elongation and flex-fatigue resistance of the film reached maximmns when acrylate copolymer content was 50%. Excessively increasing the content of acrylate copolymer reduced the film properties.

活性染料印花糊料PA──CMS的研制

本文叙述了活性染料印花糊料ＰＡ－ＣＭＳ（交联－高醚化度羧甲基淀粉）的合成原理、工艺条件、醚化度对印花性能的影响及应用效果。结果表明，ＰＡ－ＣＭＳ可以全部代替海藻酸钠用于棉和涤棉的活性印花，是一种较为理想的活性染料印花糊料，与海藻酸钠相比，成本降低４０％。

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。