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.

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.

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.

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.

New Route for Novel Polycarboxylic Starch Hybrid

Starch was polymerized with methacrylic acid (MAA) to different magnitudes of poly (MAA) using potassium persulphate/sodium thiosulphate redox initiation system. The polymerization products are referred to as “composite”. The latter consists of poly (MAA)-starch graft copolymer, poly (MAA) in the form of homopolymer, oxidized starch brought about under the influence of the initiator and intact starch. At this end, the composite, the copolymer, and the untreated (native) starch were subjected to carboxymethylation under different conditions and the rheological properties of these starch—based on products before and after carboxymethylation examined. Results obtained disclosed that the susceptibility of these products toward carboxymethylation follows the order: native starch > Copolymer > composite. Meanwhile, these products exhibit non-Newtonian thixotropic behavior before carboxymethylation;and their rheology signifies the order: Composite > copolymer > native starch whereas after carboxymethylation these products are characterized by non-Newtonian Pseudoplastic behavior. For a given rate of shear, the apparent viscosity follows the order: native starch > composite > copolymer > carboxymethyl composite > carboxymethyl starch > carboxymethyl copolymer, in contrast with pseudoplasticity which reveals an opposite order. It was also shown that the apparent viscosity increases by increasing poly (MAA) in the copolymer and composite and that redrying of the copolymer and the composite after normal precipitation and drying causes a considerable enhancement in the apparent viscosity of these products.

羟丙基淀粉植物胶囊的研究

以羟丙基淀粉(HPS)为主料,羧甲基纤维素钠(CMC-Na)和海藻酸钠(SA)为增强剂,并辅以凝胶剂和塑化剂,制备了复合植物胶囊HPS/CMC-Na/SA,采用单因素实验和正交实验优化了制备工艺,并通过SEM、FTIR、XRD对其进行表征。结果表明,当HPS加量为85 mg·mL^(-1)、CMC-Na加量为8.5 mg·mL^(-1)、SA加量为4.5 mg·mL^(-1)时,复合植物胶囊的抗拉强度为30.08 MPa,断裂伸长率为14.49%,杨氏模量为1289.77 MPa,800 nm透光率为78.068%,400 nm透光率为63.072%。

玉米淀粉制备羧甲基淀粉的研究

玉米淀粉作为一种重要的生物质资源,在食品、纺织、造纸、医药等领域有着广泛的应用。然而,传统玉米淀粉的溶解性和冻融稳定性等性能的限制,严重影响了其在工业上的应用。因此,采用异丙醇-水混合溶剂法制备羧甲基淀粉,通过调控淀粉与NaOH物质的量比、反应介质体积、异丙醇质量分数、氯乙酸钠质量和醚化时间等参数,成功制备出了取代度为0.7的高取代度羧甲基淀粉,其溶胀度达到了36.56 g.g^(-1)。该方法通过加入水,使得NaOH更好地与淀粉表面接触,同时水的存在促进了氯乙酸钠更好地进入淀粉分子内部参与反应,从而大大提高了反应效率。利用红外光谱、XRD衍射图谱、SEM等表征手段证明了羧甲基化的成功,为未来大规模生产高取代度羧甲基淀粉提供了一种简单可行的方法。

淀粉/羧甲基纤维素/甘油可降解复合膜的制备及性能研究

将淀粉和羧甲基纤维素(CMC)混合,加入甘油作为增塑剂,采用流延法制备淀粉/CMC/甘油复合膜。采用SEM、XRD、FT-IR等方法对复合膜的结构进行表征,并测试了复合膜的力学、透光、吸水和降解性能,重点探讨不同甘油添加量(以淀粉和CMC总干质量计,0~30%)对复合膜结构和性能的影响。研究结果表明:淀粉、CMC和甘油为物理共混,甘油的加入可以提高体系的相容性,甘油添加量越多,复合膜断裂面越光滑。随着甘油添加量增加,复合膜的断裂伸长率显著增大,当添加量从0增加到30%时,断裂伸长率由3.39%升高到46.23%,增大了12.6倍。复合膜的透光率、吸水率和水蒸气透过率(WVP)等性能随甘油添加量的增加而提升,当甘油添加量为20%时,600 nm透光率最大可达79.42%,WVP和吸水率分别为5.14×10^(-11) g/(m·s·Pa)和25.46%。体系中甘油添加量的增加还能够加快复合膜的降解速度,当甘油添加量为20%时,复合膜土埋9天后几乎完全降解。甘油添加量为20%时制备的淀粉/CMC/甘油复合膜的力学、光学及可降解性能较优,可以满足食品包装膜的性能要求。

机械活化协同固相法制备羧甲基多孔淀粉及其在粉末酱油中的应用

为获得一种绿色高效的羧甲基多孔淀粉制备工艺,本研究以酶解制得的多孔木薯淀粉为原料,氯乙酸钠为醚化剂,氢氧化钠为催化剂,采用机械活化协同固相醚化法制备羧甲基多孔淀粉,通过单因素实验探究各因素对羧甲基多孔淀粉取代度(Degree of substitution,DS)的影响,并探讨羧甲基多孔淀粉在酱油中的应用。结果表明,机械活化协同固相法制备羧甲基多孔淀粉的最佳工艺条件为:多孔淀粉与氯乙酸钠的物质的量之比为1:1,氢氧化钠质量分数为18.8%,球磨时间1.5 h,反应温度50℃,此条件下制备得到的羧甲基多孔淀粉取代度最高为0.2532。通过红外光谱仪(Infrared spectrometer,FTIR)、X-射线粉末衍射仪(X-ray powder diffractometer,XRD)和扫描电镜(Scanning electron microscope,SEM)等表征,进一步证实多孔淀粉发生了羧甲基化反应。随着羧甲基多孔淀粉DS的增大其冷水溶解度、吸水率和柠檬黄吸附量增大;当DS为0.2532时,羧甲基多孔淀粉的冷水溶解度达到64.94%,吸水率达到180.73%,柠檬黄吸附量达到2.5086 mg·g^(-1)。羧甲基多孔淀粉所制备的粉末酱油相比于木薯淀粉和多孔淀粉所制备的粉末酱油溶解性更好,吸潮性更低,氨基酸态氮含量更高,与原酱油最接近。因此,机械活化协同固相醚化法可有效制备羧甲基多孔淀粉,该法操作简单,绿色环保,取代高,为多孔淀粉的开发利用提供了科学依据。

三元共聚生物质基矿山爆破抑尘剂的制备及性能研究

以接枝共聚制备羧甲基纤维素钠(CMC-Na)-羧甲基淀粉钠(CMS-Na)-丙烯酰胺(AM)三元复合高分子抑尘剂,以黏度为测试指标,通过正交试验探索抑尘剂最优配比。用扫描电镜(SEM)、傅里叶红外光谱(FT-IR)、热重(TG)对接枝共聚产物进行表征,对抑尘剂黏度、抗风蚀性、保水性、渗透性等理化特性进行测试。结果表明:CMC-Na∶CMS-Na∶PVA∶AM=8∶8∶3∶16时,制备抑尘剂最大黏为52689 mPa·s;借助黏度及保水性指标确定抑尘剂喷洒最佳体积分数为8%;木质素磺酸钠和三乙醇胺最优添加量分别为抑尘剂质量分数的0.4%和4%。红外光谱显示丙烯酰胺接枝到羧甲基淀粉和羧甲基纤维素钠上,扫描电镜显示抑尘剂对粉尘的凝并和黏结性能显著,抗风蚀性实验表明抑尘剂固尘率为85.47%。

羧甲基淀粉钠/酪蛋白酸钠协同包埋柠檬香茅精油及微胶囊抑菌性能研究

为了研究柠檬香茅精油在延长泡菜货架期方面的应用。本研究以柠檬香茅精油为芯材,羧甲基淀粉钠、酪蛋白酸钠为壁材制备柠檬香茅精油微胶囊,考察羧甲基淀粉钠与酪蛋白酸钠的质量比对柠檬香茅精油微胶囊的理化性能、微观形态、热稳定性等的影响,评估微胶囊化对精油中化学成分及泡菜中主要致病菌抑菌活性的影响。结果表明,羧甲基淀粉钠与酪蛋白酸钠质量比为1:5、1:9时,精油包埋率无显著性差异(P>0.05),分别为98.29%、96.90%,其外观为球状、块状,随酪蛋白酸钠含量的增加,微胶囊表面的微孔逐渐减少,空洞变小。热失重曲线中最大失重速率的温度随酪蛋白含量增加而向高温方向移动,最高达314.27℃,纯精油仅为106.27℃。气相色谱-质谱联用(GC-MS)结果表明精油微胶囊处理保留了诸如橙花醇(34.69%)、乙酸香叶酯(27.41%)、芳樟醇(5.65%)、石竹烯(6.50%)等抑菌成分。这使得柠檬香茅精油微胶囊对泡菜中枯草芽孢杆菌(主要的腐败菌)及表皮葡萄球菌(引起包装袋胀袋的细菌)有较强的抑菌性,其最小抑菌浓度分别为97.66、195.31μg/mL,最大杀菌浓度均为1562.5μg/mL。综上所述,羧甲基淀粉钠与酪蛋白酸钠作为包封剂制备柠檬香茅精油微胶囊具有可行性,且对泡菜中主要腐败菌有抑制效果。这为进一步探究柠檬香茅精油在延长泡菜货架期上的应用提供思路。

羧甲淀粉钠微生物限度方法适用性试验研究

目的:建立羧甲淀粉钠的微生物限度检查方法。方法:依据《中国药典》2020版第四部通则1105及1106的要求对羧甲淀粉钠进行微生物限度方法适用性试验。结果:采用中和剂稀释为1∶20的供试液后进行平皿法计数,各试验菌的回收率均在0.5~2范围内;大肠埃希菌检查采用1∶20的供试液直接接种法,结果符合要求。结论:建立的中和剂方法简单可行,可有效消除羧甲淀粉钠的抑菌作用。

基于紫薯花青素/茜素的猪肉新鲜度智能指示膜研究

环境因素和微生物污染引起的食品腐败变质,不仅威胁公众健康,还造成食品资源浪费。将天然色素用于制备颜色指示型智能包装,可以监测食品品质变化。该文以羧甲基纤维素和马铃薯淀粉为成膜基材,添加紫薯花青素、茜素及其混合物制备智能指示膜,比较分析了膜的物理性能、机械性能、微观结构、颜色稳定性和pH响应性。结果表明,随着紫薯花青素和/或茜素的添加,羧甲基纤维素/马铃薯淀粉膜的厚度增加、水分含量降低、透光性下降、拉伸强度增加而断裂伸长率降低。扫描电子显微镜结果表明色素的加入使基膜的微观结构更加致密。将负载紫薯花青素和/或茜素的指示膜用于猪肉新鲜度监测,结果表明,在4℃贮藏环境下,随着时间延长,猪肉的pH值和挥发性盐基氮含量不断上升,6 d后均超过可接受限值,表明猪肉开始腐败,指示膜呈现肉眼可见的颜色变化。该研究为肉品新鲜度智能指示膜的开发提供了参考。

羧甲基淀粉钠工艺对片剂崩解性能的影响

文章着重分析羧甲基淀粉钠在用于改善难溶性药物的片剂在高湿条件下崩解不佳时的效果。以难溶性药物来曲唑作为本次研究的模型药物,采用常规的口服片剂生产工艺制备药物片剂。结果显示使用无交联工艺的羧甲基淀粉钠的片剂,在高湿条件(92.5%RH)出现崩解不佳或不崩解现象,使用经交联工艺的羧甲基淀粉钠的片剂在高湿条件(92.5%RH)下崩解良好。经交联化的羧甲基淀粉钠空间结构更强,在高湿条件下的凝胶化反应较弱,吸湿溶胀后仍有一定的空间间隙供水分进入片芯,故而合理控制反应过程中氢氧化钠浓度和交联剂用量可使难溶性药物在高湿条件下保持良好的崩解性能。

煤尘润湿-凝聚复合型绿色抑尘材料制备及性能研究

煤炭作为我国经济支柱,煤尘问题日益凸显,影响职业健康与环境。针对现有抑尘剂成本高、污染重的问题,本研究采用羧甲基纤维素钠和淀粉为主原料,结合过硫酸铵和N,N'-亚甲基双丙烯酰胺,成功制备新型煤尘抑制剂。经单因素分析优化配比与反应条件,通过扫描电镜、吸水性及抗压实验验证其优良性能与高效抑尘效果。该抑制剂成本低、环保,为煤炭行业可持续发展提供了新方案。

响应面优化羧甲基醚化法制备马蹄抗性淀粉的工艺及理化性质研究

本实验以马蹄淀粉为原料通过羧甲基醚化法制取抗性淀粉,以羧甲基醚化马蹄抗性淀粉的得率为评价指标,通过单因素试验和Box-Behnken响应面试验优化其制备工艺,并对所得产品进行感官评价和理化指标分析。结果表明,羧甲基醚化法制备马蹄抗性淀粉的最优工艺参数为马蹄淀粉乳浓度12%,醚化剂用量120%,醚化温度43℃,该工艺下马蹄抗性淀粉得率为75.85%,与预测值76.02%接近,表明实验结果可靠。通过此方法可以便捷高效地生产出持水性强、颗粒较为完好、品质优良的马蹄抗性淀粉,为工业化生产提供了理论参考。

一种快速准确测定羧甲基淀粉取代度的方法

传统的络合滴定法测定羧甲基淀粉取代度(DS)时,存在耗时长,稳定性差,高取代度羧甲基淀粉测定效果差等问题。本文采用将过量CuSO4溶液加入pH6.0～7.0的变性淀粉溶液中,生成羧甲基淀粉铜沉淀,过滤除去沉淀,再调节pH至7.5～8.0后,采用1-2-吡啶偶氮-2-萘酚(PAN)为指示剂,用EDTA标准溶液滴定过量的Cu2+的方法来测定羧甲基淀粉的DS。该法简便快速,准确可靠,稳定性好,可适用于羧甲基淀粉工业简便快速的检测。

交联——羧甲基复合变性淀粉的制备及性能研究

本文制备了交联—羧甲基复合变性淀粉 ,通过扫描电镜对其结构进行了观察 ,对产品的特性进行了研究。结果表明 :此产品糊液的稳定性好、透明度高、抗冻性好、耐老化 。