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.

Synthesis of Ionic and Non-Ionic Modified Waterborne Polyurethane Curing Agent

By using HDI and TMP as the main raw materials,polyethylene glycol 400(PEG400)is used as a non-ionic hydrophilic modifier,and sodium hydroxyethyl sulfonate is used as an ionic hydrophilic modifier to synthesize a dual hydrophilic modified polyurethane curing agent.Research revealed that introducing PEG400 for hydrophilic chain segments and sodium hydroxyethyl sulfonate for hydrophilic ionic groups in the polyurethane curing agent component leads to a uniform distribution of hydrophilic components,significantly enhancing compatibility with the aqueous polyol component,and results in excellent film performance.The synthesis process and film were characterized using Fourier transform infrared spectroscopy and high-resolution scanning electron microscopy in the study.

Synthesis and Characterization of Waterborne Epoxy Curing Agent Modified by Silane

治好代理人的新奇水运的环氧基树脂作为一个结束代理人用 3-glycidoxypropyl trimethoxysilane (GPTMS ) 被准备使内收，它被 triethylene tetramine (TETA ) 和液体环氧基树脂树脂(E-51 ) 综合。合成过程上的反应温度和时间的效果试验性地被调查。粒子尺寸和治好的代理人的水分散的分发被散布的动态光(DLS ) 测量。产品的结构被 Fourier 变换描绘红外线的分光计(FTIR ) 和 1H-nuclear 磁性的回声(1H NMR ) 。综合治好的代理人和它治好的环氧基树脂树脂电影的性质也被测量。结果证明为合成的适当温度使内收在 65 75 ° C，反应时间是 4 5h，并且治好代理人合成的合适的反应温度是 75 85 ° C 和反应时间，这是 3 4h。当 GPTMS 和醋酸的集体比率是 3% 时 5% 和 5%10% 分别地，坚硬，水抵抗和治好的电影的粘附显著地被改进。

Synthesis and Curing Properties of a Novel Novolac Curing Agent Containing Naphthyl and Dicyclopentadiene Moieties

A novel novolac curing agent containing both naphthalene and dicyclopentadiene (DCPD) moieties was prepared to produce a highly heat-resistant cured polymer network. The chemical structure was characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance, mass spectrometry, and gel permeation chro-matography analyses. The thermal properties of the resulting polymer from diglycidyl ether of bisphenol A epoxy resin cured with the novel curing agent were evaluated using dynamic mechanical thermal analysis and thermogra-vimetric analysis. Compared with the conventional curing agent, the resulting polymer cured with naphtha-lene/DCPD navolac shows considerable improvement in heat resistant properties such as higher glass transition temperature (Tg) and thermal stability. The result also shows better moisture resistance because of the hydrophobic nature of naphthalene/DCPD structure.

Solidification Efficiency and Mechanism of Conventional Curing Agents for Sewage Sludge Stabilization and Dewatering

One of the challenges faced by sewage sludge treatment and disposal is its higher water content,and how to efficient dewater those hazardous materials properly is welcome in practice. This study stabilized the sewage sludge via the using of conventional curing agents and calcined aluminum salts,and the corresponding dewatering mechanisms and structural changes of the stabilized sludge were further comparable analyzed.Experimental results showed that wollastonite and kaolin exhibit a relative higher dewatering efficiency as compared to other conventional curing agents; however the releasing rate of heavy metals of Cu,Cr,Ni for kaolin solidification and Zn,Pb for wollastonite solidification is higher than the sludge samples solidified by other curing agents. For comparison,the sludge samples solidified by calcined aluminum salts (AS),calcium ash,Mg-based curing agent,tricalcium aluminate( C_3A) show a lower heavy metals leaching potential and unconfined compressive strength. In addition,the economic characteristics and local availability of AS,calcium ash,C_3A and CaO makes it have a broad prospect in extension and application. These findings are of great significance for stabilization and dewatering of sewage sludge.

PREPARATION AND PROPERTIES OF THERMOSETTING ACRYLIC COATINGS USING TITANIUM-OXO-CLUSTER AS A CURING AGENT

Thermosetting acrylic coatings were prepared by using carboxyl acid group-containing acrylic oligomer and curing with titanium-oxo-clusters which were first pre-hydrolyzed from titanium n-butoxide.The curing ability of the titanium-oxo-cluster was examined using a microdielectric analytical(DEA)curing monitor,Fourier transformed infrared spectroscopy(FTIR),and Soxhlet extraction experiments,and the properties of the resulted coatings were investigated with pendulum hardness tester,dynamic mechanical analysis(DMA),thermogravimetric analysis(TGA)and ultraviolet-visible spectrometer.The effect of titania-oxo-cluster in leading acrylic oligomers to form thermosetting acrylic coatings was confirmed.An increasing pendulum hardness and modulus of acrylic coatings with increasing titania content was observed, which resulted from the increment of crosslinking degree rather than of the titania content.The thermosetting acrylic/titania coatings also showed better thermal stability and higher UV-blocking properties than those coatings using organic curing agent.

Synthesis and Application of a Polymeric Crosslinking Agent for Improving Fixation of Vinylsulfone-type Dyes on Cotton by a Pad-dry-cure Process

A new class of novel polymeric crosslinking agent (NPCA), which contained silane coupling group and the epoxy groups, was designed and synthesized in our laboratory. NPCA was a non-formaldehyde multifunctional crosslinking polymer. The cotton fabrics dyed with 8.0%(owf)Vinylsulpone-type dyes were treated with 3.0%4.0% NPCA, 0.5 mol/L potassium thiocyanate as a catalyst, then padded through two dips and two nips to reach a wet pickup of 80%85%, then dried at 80℃ for 2 minutes and cured in oven at 140150℃ for 3 minutes. Crocking fastness and fixation (%) were improved with up to 1.01.5 units, 35%50%, respectively. And there was little difference between the color yield of dyed fabrics before and after the treatment at certain conditions. The possible crosslinking mechanism of NPCA was also investigated. It was concluded that NPCA can improve colorfastness of cotton fabric by means of the three-dimensional network, covalent bonding and other molecular forces.

有机肥+生物炭+微生物菌剂配施对烤烟多酚和化学成分的影响

以云烟87为研究对象,采用三因素三水平正交试验设计,设置3个生物炭(900、1800、2700 kg/hm^(2))、3个微生物菌剂(30、60、90 kg/hm^(2))和3种有机肥(羊粪肥、芝麻饼肥、菜籽饼肥)组合成9个处理,并以无机肥为对照处理,研究了上述因素对烤后烟叶多酚类和常规化学成分的影响。结果表明:生物炭施用量是影响烤烟的多酚和化学成分含量的主效因素,随着生物炭施用量的增加,烟叶的总糖、还原糖及各种多酚类物质含量均有所增加,施用2700 kg/hm^(2)生物炭的整体表现较优。微生物菌剂也是重要的影响因素,随着微生物菌剂施用量的增加,烟叶的总糖、还原糖、多酚类、绿原酸含量均有所增加,施用60 kg/hm^(2)微生物菌剂的整体表现较优。施用有机肥的影响则较小,其中,羊粪肥的表现相对较好。综上,最佳组合方式为2700 kg/hm^(2)生物炭+60 kg/hm^(2)微生物菌剂+羊粪肥,并且将其可应用于凉山产区烤烟的施肥管理中。

水泥基材料无机/有机复合内养护剂的研究进展

无机/有机复合吸水材料具有一定的亲水基团和三维网络结构,吸水性、保水性和释水性优异,是水泥基材料重要的内养护剂之一。通过在水泥基材料中引入无机/有机复合吸水材料,利用其吸-释水特性可自动调节水泥基材料内部相对湿度,促进水化反应,减少水泥基材料自收缩和早期开裂等现象,提高力学性能和耐久性。概述了无机/有机复合内养护剂(CICA)的制备方法、结构特征以及吸-释水行为;综述了CICA对水泥基材料水化进程、微观结构、宏观性能和耐久性的影响;展望了CICA在混凝土应用的发展前景,为CICA在水泥基内养护中的应用提供一定理论指导和技术参考。

施用不同有益菌剂对长期连作烤烟根际土壤微生态的影响

【目的】探究不同有益菌剂对长期连作烤烟根际土壤微生态环境的影响,为连作土壤改良及连作障碍消减提供参考依据。【方法】采用盆栽试验和高通量测序技术,分析长期连作烤烟后添加有益菌哈茨木霉菌剂T-22(T1处理)、枯草芽孢杆菌剂(T2处理)、哈茨木霉菌剂T-22+枯草芽孢杆菌剂(T3处理)的烤烟根际土壤理化性质、酶活性及微生物群落结构和功能。【结果】相较于不施有益菌(对照,CK),施用有益菌剂可提高长期连作烤烟根际土壤的速效养分含量和酶活性,其中,在10个环境因子中,速效磷(AP)含量对烤烟根际土壤细菌群落分布的贡献度(4.97%)最高,碱解氮(AN)含量对烤烟根际土壤真菌群落分布的贡献度(6.91%)最高,蔗糖酶(SC)活性对烤烟根际土壤真菌群落分布的贡献度(6.75%)次之;施用有益菌剂可提高长期连作烤烟根际土壤微生物群落丰度、多样性指数和细菌特有OTUs数;施用有益菌剂可改变长期连作烤烟根际土壤的指示物种丰度,其中,细菌假单胞菌属(Pseudomonas)为T1处理的指示物种,鞘氨醇单胞菌属(Sphingomonas)和被孢霉属(Mortierella)为T1处理的优势菌属,丰度分别为12.2%和25.0%,Minimedusa属为T3处理的指示物种。单施细菌有益菌剂可降低长期连作烤烟根际土壤细菌群落主要代谢途径的丰度,单施真菌有益菌剂则相反;单施真菌、细菌与真菌有益菌剂混施可提高烤烟根际土壤真菌代谢途径的丰度。【结论】施用有益菌剂对长期连作烤烟根际土壤微生态环境具有一定的改良效应,其中,哈茨木霉T-22的施用效果较好,可用于烤烟连作障碍防控。

持续负温(-5℃)养护条件下含气混凝土性能劣化及孔结构发展规律试验研究

通过对比负温养护、标准养护条件下5种不同含气混凝土试块在不同龄期下的抗压强度值及内部孔结构,分析持续负温(-5℃)养护条件下含气混凝土抗压强度的发展规律,针对持续负温(-5℃)养护条件,对少害孔的范围进一步明确;并从混凝土内部孔隙分布状况对引气类混凝土普遍存在的强度缺失进行研究。试验结果表明:持续负温(-5℃)条件养护对含气混凝土抗压强度的增长有明显的抑制作用,相同引气剂掺量下混凝土试块强度均小于标准养护试块的强度;同种养护条件下,受引气剂影响,混凝土的强度与引气剂掺量间均呈现负相关;在负温养护环境条件下,实验中设置的最高掺量(0.2%引气剂掺量组别)含气混凝土结构整体密实性因浆体内部孔隙数量的增加而减弱,对混凝土自身的强度有一定影响,但引气剂的加入对负温环境混凝土的抗冻作用不可忽视。为了分析负温环境与引气剂掺量之间的平衡性,通过对含气混凝土在不同养护条件下孔结构发展规律的研究,在保证含气混凝土抗压强度劣化程度低、孔径结构相对优化的前提下,明确了负温(-5℃)条件下含气混凝土引气剂的最优掺量。

基于响应面法的碱硫酸盐激发固废型固化剂组成优化设计

论文采用响应面法对碱-硫酸盐激发固废型固化剂体系进行优化,以赤泥、矿渣、生石灰和脱硫石膏为变量因素,以流态固化土的7 d、28 d无侧限抗压强度和流动扩展度为评价指标,建立预测模型。结果表明:当赤泥掺量为26.6%、矿渣掺量为53.2%、石灰掺量为11.7%、脱硫石膏掺量为8.5%时,流态固化土的工作性能和力学性能均达到最优,响应值的实测值和预测值误差范围控制在5%内,表明该响应面法预测模型预测精度高。

复合型固化剂固化黏土强度试验研究

为研究固化剂-黏土的强度特性,养护7 d后,对不同水泥含量的固化土采用单轴无侧限压缩试验。试件处于干燥和泡水两种状态,测得黏土、固化剂掺入黏土、固化剂与水玻璃掺入黏土三种情况下试件单轴无侧限抗压强度。分析黏土名义黏聚力c′的演化特征。试验结果表明:其他条件不变,随着水泥含量的增大,试件强度先减小后增大,当水泥含量(质量分数)为7%时,试件强度最低;加入固化剂后的泡水试件强度随着水泥含量的增大而增大;加入固化剂能显著提高试件的抗压强度;加入固化剂和水玻璃,试件强度与单独加入固化剂相差不大;名义黏聚力c′与无侧限单轴抗压强度变化规律一致。

一种耐酸耐碱高强树脂的合成及性能

小套管二次固井是一种新型的固井工艺,针对目前由于水泥自身脆性大易气窜和水窜且为碱性固化体、易受压产生裂缝、易受酸性介质破坏的问题,以D-33二元醇和顺丁烯二酸为原料,苯乙烯作为活性稀释剂合成了一种不饱和型聚酯树脂。在树脂体系中引入填料,提高产品韧性及抗压强度。采用傅里叶变换红外光谱仪对树脂进行表征;通过万能试验机对树脂体系进行性能评价。结果表明,目标产物包含羰基、碳碳双键和苯环对位取代结构的特征峰,固化体系为过氧化二苯甲酰/N,N-二甲基苯胺,其在50℃、60℃和70℃条件下的添加量分别为0.2%/0.02%、0.1%/0.02%、0.1%/0.01%,万能试验机测试结果显示,在50℃、60℃和70℃下养护24h后的抗压强度分别约为50MPa、70MPa、90MPa。实验获得了一种聚合时间可调、黏度小、抗压强度高且耐酸耐碱的固井材料,有望在水平井重复压裂改造中大规模使用。

OPC-MCA固化剂对盾构废泥的固化性能及其微观作用机制研究

通过添加高炉矿渣(GGBS)、脱硫石膏(FGDG)、铝酸钙粉、生石灰和明矾到普通硅酸盐水泥P.O42.5(OPC)中,制备一种新型盾构废泥改良材料OPC-MCA。首先,通过正交测试法确定OPC-MCA中各原料的最优配比。然后,使用该材料和OPC在10%~40%的掺量下处理芜湖市城南过江隧道工程产生的盾构废泥,并检测不同固化时间(3、7、28 d)下的抗压强度。最后,采用扫描电镜(SEM)、工业CT系统和X射线衍射(XRD)观察和分析固化后废泥试样的微观形貌、孔隙和裂纹特征以及矿物成分变化。研究结果表明:OPCMCA的最优材料配比为51%OPC、32%GGBS、8%FGDG、5%铝酸钙粉、3%生石灰、1%明矾;OPCMCA对芜湖盾构废泥的固化能力比OPC的强,在低掺量情况下更是如此;固化剂掺量和固化时间的增加会导致试样强度增加、脆性增强,并使部分试样转变为拉伸破坏;在OPC-MCA固化的试样中检测到了OPC固化试样中未检测到的水化硅铝酸钙(C-A-S-H)和单硫型硫铝酸盐(AFm),并且钙矾石(AFt)含量也更高;在同等掺量下,OPC-MCA固化试样中大尺寸孔隙的比例以及孔隙的总体积均比OPC固化试样的小。

钻井废弃泥浆固化土力学特性试验分析

石油开采过程中产生大量钻井废弃泥浆,直接排放会造成环境污染,对钻井废弃泥浆进行处理势在必行。针对钻井废弃泥浆采用固化处理方法,并对固化土的力学特性进行系统试验分析。研究结果表明:固化土的应力应变曲线为应变软化型,发生脆性破坏;曲线峰值随着围压的增加和养护龄期的延长而升高;随冻融循环次数的增加而降低,6—8次后趋于稳定,冻融循环对固化土的强度影响明显。固化土发生刚度软化现象,E-ε曲线整体呈下降趋势,刚度随着围压的增加和养护龄期的延长而增加,随冻融循环次数的增加而降低,无量纲化割线模量与无量纲化主应力差的关系曲线由两部分组成,呈现倒C型。对固化土力学性能的研究有利于废弃泥浆的资源化再利用。

1,3-二(2′-氨基亚乙基)-2-甲基咪唑溴盐与环氧树脂E-51的固化工艺

通过咪唑环上的季铵化反应,制备一种适用于环氧树脂的双氨基咪唑类离子液体固化剂1,3-二(2′-氨基亚乙基)-2-甲基咪唑溴盐(DAIL)。以环氧树脂E-51作为基体树脂,深入研究DAIL作为固化剂的固化工艺条件和固化物的性能。结果表明,DAIL可作为环氧树脂E-51的中温固化剂使用,二者的最佳质量比为DAIL∶E-51=20∶100,最佳固化温度范围为74~105℃,后固化温度为162℃,固化后的浇注体样条抗拉强度为159 MPa,弹性模量为2281 MPa,断裂伸长率为12.8%,热分解温度为424.4℃。DMA分析表明DAIL/E-51浇注体最大损耗因子tanδ为0.56,玻璃转化温度θg为83℃,对应的贮存模量E为290 MPa,交联密度为30149 mol·m^(-3)。该结果为高力学性能中温环氧树脂固化剂的使用提供了重要实验依据。

潟湖污泥改性土工程特性与环境风险研究

为实现典型潟湖污泥的无害化处理与资源化利用,文章以海南万宁市小海潟湖污泥为研究对象,利用高炉矿渣、钢渣、工业石膏等大宗工业固废为原料制备的软土固化剂对污泥土进行固化处理。结果显示,软土固化剂改善了潟湖污泥的抗压强度、抗剪强度以及液塑限等工程性能,降低了污泥土中的重金属浸出浓度与迁移释放能力,同时增加了种子发芽指数,使改性污泥土能够满足建设用地回填土强度要求与园林绿化用土的安全指标。通过SEM、XRD表征分析发现,潟湖污泥原样中的硅、铝成分,在碱性激发剂、钢渣粉、矿粉等提供的碱性环境下参与了水化反应,使改性污泥土表面出现大量孔洞以及棒状、片状等稳定的结晶物和以凝胶态存在的水化产物,进一步使污泥土内部结构密实紧凑,颗粒间联结增强。经过软土固化剂固化后的潟湖污泥土工程特性得到显著提升,并使污泥中重金属得到固化稳定化,其环境生态毒害性也得到有效减弱。

复合型固化剂加固黄土物理力学特性试验研究

为研究复合型固化剂对兰州黄土的加固效果,通过一系列物理力学特性试验和微观结构分析,对不同配合比的复合型固化剂加固黄土的击实特性、无侧限抗压强度、抗剪强度参数、破坏模式和微观结构展开研究。结果表明:复合型固化剂可显著改善黄土的击实特性和水敏性,增大无侧限抗压强度和抗剪强度参数,0.2 L/m^(3)F1+3%水泥是复合型固化剂加固黄土的最佳配合比;与天然黄土相比,最佳配合比的复合型固化剂加固黄土的无侧限抗压强度、内摩擦角和黏聚力分别增大了633.26%、19.41%和421.18%,无侧限条件和围压为200 kPa时,试样的破坏应变分别减小了15.79%和25.00%,破坏应力分别增大了633.84%和127.66%;复合型固化剂通过F1离子交换作用和水泥水化反应,改变了粒间接触和排列方式,显著减小黄土中小孔隙和孔隙度,促进土颗粒团聚,提高密实度和强度。与天然黄土相比,最佳配合比的复合型固化剂加固黄土后孔隙度减小了5.91%。