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.

Influence of subsequent curing on water sorptivity and pore structure of steam-cured concrete

Steam-cured condition is found to cause larger porosity and worse properties of concrete compared with normal curing condition. For the sake of seeking effective measurements to eliminate this bad effect of steam-cured condition on concrete, the water sorptivity and pore structure of steam-cured concretes exposed to different subsequent curing conditions were investigated after steam-curing treatment. The capillary absorption coefficient and porosity of the corresponding concretes were analyzed, and their mechanisms were also discussed. The results indicate that water sorptivity and pore structure of steam-cured concrete are greatly influenced by the curing condition used in subsequent ages. Exposure steam-cured concrete to air condition has an obviously bad effect on its properties and microstructures. Adopting subsequent curing of immersing steam-cured concrete into about 20℃ water after steam curing period can significantly decrease its capillary absorption coefficient and porosity. Steam-cured concrete with 7 d water curing has minimum capillary absorption coefficient and total porosity. Its water sorptivity is decreased by 23% compared with standard curing concrete and the porosity is 9.6% lower. Moreover, the corresponding gradient of water sorptivity and porosity of steam-cured concrete both decrease, thus mictostructure of concrete becomes more homogeneous.

Cure Behaviors and Water Up-take Evaluation of a New Waterborne Epoxy Resin

Cure behaviors and water up-take evaluation of a low cost, ecofriendly and water soluble epoxy resin prepared by reaction between epichlorohydrin and PEG400, PEG600 and PEG1000, respectively, were investigated using non-isothermal differential scanning calorimetry （DSC） and gravimetrical method, respectively. Factors affecting the cure behaviors as well as water up-take of waterborne epoxy resins, such as amount of triethylenetetramine （TETA） and triethylene diamine （TEDA）, PEG molecular weight, curing temperature, were systematically investigated. The prepared water soluble epoxy resins can be cured under room temperature with the shape of the curing curves similar to that expected for an autocatalytic reaction.

Internal Curing Using Water-releasing Material for High Strength Micro-expansive Concrete

Due to its low water content, it is difficult for expansive agent to have an effective expansive effect on high strength concrete to compensate its extensive shrinkage and form a certain expansion. To solve this problem, water-releasing material with water storage and releasing characteristics was incorporated into high strength micro-expansive concrete to provide internal curing, and expansive effect of expansive agent was improved. Migration of water from initially saturated water-releasing material to the surrounding hydrating cement paste was investigated. Based on a given efficient diffusion distance of water stored in water-releasing material, the mass and real water-cement ratio of cured cement paste were estimated. At the same time, the effect of internal curing of water-releasing material on the volume deformation of high strength micro-expansive concrete was investigated.

Effects of secondary water curing on the long-term strength and durability of concrete after steam-autoclave curing

To study the effects of secondary water( SW) curing of 20 ℃ for 7 d on concrete long-term strength and durability after steam-autoclave curing, concrete specimens were fabricated and subjected to standard,steam-autoclave or steamautoclave + SW curing. The compressive strength,accelerated carbonation depth, and Coulomb electric charges of the specimens were tested at the ages of 28,90,180,and 360 d.Furthermore,mercury intrusion porosimetry experiments on the specimens were conducted at the age of 180 d. Results indicate that compared with standard curing,steam-autoclave curing can enhance the early-age strength of concrete; however, it is detrimental to the development of later-age strength, and reduces chloride and carbonation resistance. Due to the replenishment of water into concrete,SW curing can refine the micro-pore size and decrease the ratio of harmful and more harmful pores in concrete. As a result,SW curing is effective in improving the long-term strength and durability of steamautoclaved concrete,and makes it approach that under standard curing. The improvement amplitudes of SW curing on the concrete compressive strength, chloride and carbonation resistance at 360 d can reach 20. 3%,48. 6%,and 80. 9%,respectively.

Effects of Curing Methods on the Permeability and Mechanism of Cover Concrete

Curing methods are one of the most important factors in determining the quality and compactness of cover concrete.The effect of curing methods on the water absorption and sorptivity coefficient of cover concrete with the substitution ratio of fly ash(FA)and ground granulated blast slag(GGBS)for cement between 30 wt%and 40 wt%was studied by capillary water absorption test.The vacuum saturation test and mercury intrusion test were employed to characterize these differences in the pore structure of cover concrete under different curing methods.With further analysis of the compactness of microstructure by SEM,the mechanism of the impact of curing methods on the permeability of cover concrete was revealed.The results obtained indicate that the effect of curing methods on the water absorption,sorptivity coefficient and porosity of cover concrete shows the trend of natural curing>cover curing>water curing>standard curing.It is also shown that reasonable curing is advantageous to reduce the porosity and permeability of cover concrete.In natural curing conditions,the appearance of porosity increasing and pore structure coarsening is more critical for covering concrete with mineral admixtures than for pure cement concrete.Therefore,the permeability of cover concrete with mineral admixtures is more sensitive to the early-age curing methods.

保水剂施用量对西南紫色土水分和养分特征及烟叶品质的影响

[目的]揭示保水剂聚丙烯酸钾不同施用量对西南烟区紫色土水分、土壤孔隙状况、土壤养分特征及烟叶品质的影响,为缓解季节性干旱区植烟土壤水分缺乏及高产优质的烟草生产提供重要参考。[方法]采用随机区组设计,定量研究了不同保水剂施用量条件下的紫色土水分、养分及烟叶品质特征。[结果]保水剂添加后,土壤pH值变化范围为7.4~7.7,土壤总孔隙度、毛管孔隙度、土壤饱和含水量、田间持水量、毛管含水量均呈先增大后减小变化规律,当保水剂施用量为150 kg/hm^(2)时,土壤容重达到最低值,土壤总孔隙度和毛管孔隙度、土壤饱和含水量、毛管含水量均达到最大值。土壤的阳离子交换量(CEC值)呈现出波动式变化。土壤有机碳、全钾和速效钾含量随着保水剂施用量的增加呈先增加后降低的趋势,土壤全氮、全磷、碱解氮和速效磷含量呈逐渐增加趋势。土壤容重呈现出先减小后增大的趋势。烟叶氯含量、总氮含量变化为上部叶<中部叶<下部叶。随着保水剂施用浓度的增加,烟叶氯含量呈波动变化。中上部烟叶含钾量高于下部烟叶含钾量且随保水剂施用浓度的增加略有增加。烟碱含量变化为上部叶>中部叶>下部叶,且烟碱含量与保水剂施用浓度相关性较弱。烟叶还原糖和总糖的变化趋势较为一致。不同部位的烟叶钾氯比表现为上部叶>中部叶>下部叶,且最随着保水剂施用浓度的增加,烟叶钾氯比呈波动态变化。不同叶位烟碱/总氮比和糖碱比均表现为上部叶<中部叶<下部叶,且随着保水剂浓度的增大,均表现为递增趋势。植烟土壤全氮含量与不同叶位的烟叶氯含量、上部叶含钾量、还原糖含量之间均呈显著正相关关系(p<0.05)。不同叶位烟叶氯含量、还原糖含量、上部烟叶钾含量、下部烟叶烟碱含量均与土壤有机碳间存在显著正相关关系(p<0.05)。[结论]保水剂为150 kg/hm^(2)对于西南紫色土的改良效果最佳,研究可为植烟土壤抗旱性能增强及烟叶品质的提升提供科学依据。

控水促根和延迟移栽对烤烟产量和品质的影响

为明确控水促根和稀播培育可延迟移栽的长叶龄壮根苗对烤烟产量和品质的影响,以云烟87为材料,设计控水促根方式和苗龄两个因素,分析不同处理烤烟的经济性状、物理特性、化学成分、感官质量差异,综合评价不同处理产质量综合效果;采用η2值评价控水促根和稀播培育长叶龄烟苗及其互作的贡献率。结果表明:扩大育苗盘孔径、基质中添加微生物菌剂、育苗后期湿润水分管理可培育长苗龄烟苗,有利于提高烤烟产量、产值和经济性状指数,改善烟叶物理特性,提升烟叶化学成分可用性,提高烟叶感官质量和烟叶产质量综合效果指数。控水促根、稀播培育长叶龄烟草及其互作对烤烟经济性状的贡献率分别为18.15%、63.38%、18.46%,对烟叶物理特性的贡献率分别为24.39%、35.74%、39.87%,对烟叶化学成分的贡献率分别为27.48%、37.47%、35.05%,对烟叶感官质量的贡献率分别为22.04%、66.21%、11.74%。因此,采用控水促根和稀播培育可延迟移栽的长苗龄壮根苗,有利于促进南方多雨稻作烟区的烤烟早生快发,提高稻茬烤烟产量和品质,具有推广价值。

某锂矿低温熟化—水浸提锂和提纯高纯石英新工艺

皖南低品位热液蚀变型锂矿Li_(2)O含量0.21%,属于新类型锂矿资源,主要矿物成分有长石、石英、白云母、绿泥石,锂主要以晶格形式赋存于锂绿泥石中。新工艺采用-1 mm原矿筛分,+0.425 mm粒级进入磨矿,制备-0.425+0.074 mm合格粒级。脱泥后合格粒级产品经磁选得云母精矿,非磁性物浮选得到长石精矿和石英精矿,长石精矿和云母精矿分别进行提锂,石英精矿进行酸处理提纯得高纯石英。将原矿筛出的-0.074 mm细泥、再磨产生的-0.074 mm细泥、合格粒级搅拌擦洗产生的-0.074 mm细泥,合并为总泥进行后续提锂。试验结果表明:总泥、云母、长石分别采用低温熟化—水浸工艺提锂,累计得Li_(2)O浸出率88.78%,酸浸后石英精矿含SiO_(2)99.942%,Fe 4.38 mg/kg,达到高纯石英低端产品要求,提锂后的长石和云母浸渣产率54.48%,可用于建筑材料。浸出前后样品的XRD和SEM分析表明,硫酸低温熟化破坏了锂绿泥石晶格结构,H+代替锂绿泥石中Li+,将锂释放出来。新工艺降低了磨矿成本,锂浸出率高,兼顾云母、石英、长石的回收,减少了尾矿排放,提高了低品位热液蚀变型锂矿的综合利用水平。

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。

后续养护方式缓解蒸汽养护混凝土性能缺陷的试验研究

为研究后续养护缓解蒸汽养护造成的永久损伤,以蒸汽养护混凝土为例,设计了4种后续养护方式,测试不同后续养护方法对混凝土抗压强度、吸附系数、氯离子扩散系数和透气性等性能参数的影响。结果表明,后续养护方式对混凝土试件28 d强度增长贡献率由大到小为标准养护、饱和石灰水养护、水养护和空气养护;混凝土毛细吸附性、氯离子扩散性和透气性曲线均呈近似“L”形,即随养护时间增加而降低,且前期(龄期3 d前)下降显著,后期趋于平缓;蒸汽养护混凝土预制构件均应及时进行适当加湿养护,但不建议长时间浸泡于水环境中养护。

碱激发矿粉胶凝材料固化高含盐量浓缩液污泥试验研究

采用浸没式燃烧工艺处理生活垃圾填埋场渗滤液产生的浓缩液污泥副产物具有高易溶盐含量的特征。分别采用硫铝酸盐水泥和碱激发矿粉胶凝材料固化浓缩液污泥,对固化试样进行一系列无侧限抗压强度(UCS)试验、水稳定性试验和微观观测试验,分析硫铝酸盐水泥和碱激发矿粉胶凝材料对浓缩液污泥的固化效果和固化机理。研究结果表明:40%水泥掺量的固化试样的28 d无侧限抗压强度为1.95 MPa,浸水28 d后降低至零。30%矿粉掺量的固化试样的28 d无侧限抗压强度为14.8 MPa,浸水28 d后,仍达3.6 MPa,远大于垃圾填埋场的填埋强度要求。碱激发矿粉反应生成的三维网状胶凝材料和钙矾石晶体可对浓缩液污泥颗粒实现有效的包裹和胶结,是碱激发矿粉胶凝材料固化浓缩液污泥的微观固化机制。

水氮耦合对陕南烤烟渗透调节物质及抗逆生理特性的影响

以云烟99为材料,采用双因素完全组合法,设置W1(土壤相对含水量75%~85%)、W2(土壤相对含水量55%~65%)、W3(土壤相对含水量35%~45%)3个土壤水分条件和N1(4 g)、N2(5 g)、N3(6 g)3个单株施氮量,共9个处理,进行盆栽试验,旺长期控水15 d后测定烟叶过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性及可溶性蛋白、可溶性糖、脯氨酸(Pro)、还原型谷胱甘肽(GSH)、抗坏血酸(AsA)、丙二醛(MDA)、超氧阴离子自由基(O2-)含量,分析水氮耦合对烤烟渗透调节物质及抗逆生理特性的影响。结果表明:在W3条件下,增施氮可提高可溶性蛋白含量,与W3N1处理相比,W3N2、W3N3分别提高25.36%和42.86%,能降低可溶性糖含量,分别降低3.85%和12.32%;W2N2、W2N3与W2N1处理相比,SOD活性分别提高20.29%和31.19%,POD活性分别提高24.60%和44.89%;N2条件下,与W1N1处理相比,W1N2和W2N2处理的CAT活性分别提高40.26%、43.58%;W3处理增加了烟叶Pro、GSH、MDA及O2-含量,与W1N1处理相比,增幅分别达69.69%~222.49%、15.2%~89.36%、155.15%~162.37%、24.89%~72.34%。分析互作效应发现,土壤相对含水量对SOD、POD活性及Pro、GSH、MDA、O2-、可溶性糖含量的影响较大;而施氮量对可溶性蛋白含量、CAT活性的影响较大;二者的互作效应对AsA含量的影响较大。综合来看,轻度缺水时株施氮量6 g的处理对烤烟抗氧化酶活性的提升效果较好,而重度缺水时株施氮量为5 g的处理对烤烟渗透调节物质和抗氧化物质含量的提升效果较好。

改性方法对玉米秸秆纤维素-腐植酸基吸水树脂性能的影响

分别采用等离子体和紫外固化法对玉米秸秆纤维素-腐植酸基吸水树脂(CS-HA-PAA)进行改性,通过傅里叶变换红外光谱仪和扫描电子显微镜对改性吸水树脂的结构和形貌进行表征,考察了改性吸水树脂的耐盐性、耐酸碱性、保水性、反复吸液性等性能。结果表明:改性后CS-HA-PAA亲水基团增多,表面粗糙且产生孔洞结构,有利于提高吸水性能;采用最佳工艺条件制备的等离子体改性CS-HA-PAA和紫外固化改性CS-HA-PAA的吸水率分别可达1053.2g/g、869.44g/g,NaCl质量浓度为9g/L时最高吸盐水率分别为181.03g/g、151.49g/g,等离子体改性CS-HA-PAA的吸水、耐盐性能优于紫外固化法改性CS-HA-PAA。

山东烤烟水溶性糖和Amadori化合物组成特征及其对感官质量的影响

【目的】明晰山东烤烟上、中2个部位B2F、C3F烟叶中水溶性糖和Amadori化合物组分构成及含量分布特征,分析化合物对烤烟感官质量的影响,为改进和精准调控山东烤烟感官品质提供数据支持。【方法】选取山东主产区生产的烤烟B2F和C3F叶片为试验材料,利用气相色谱—质谱联用技术(GC-MS)和高效液相色谱—三重四极杆串联质谱技术(HPLC-MS/MS)对烤烟中水溶性糖和Amadori化合物进行分析,通过正交偏最小二乘判别分析(OPLS-DA)方法对B2F和C3F烟叶样品进行判别分析,并对卷烟样品进行评吸,通过相关分析揭示与山东烤烟各感官质量指标呈正/负相关的关键化学成分。【结果】定性定量分析山东烤烟中16种水溶性糖和8种Amadori化合物,其中葡萄糖和果糖含量较高,蔗糖次之,其余水溶性糖含量较低;B2F和C3F烟叶间阿拉伯糖醇、阿洛酮糖和甘露醇含量差异显著(P<0.05,下同),C3F烟叶的阿拉伯糖醇含量是B2F烟叶的1.50倍,B2F烟叶的阿洛酮糖和甘露醇含量分别是C3F烟叶的1.26和48.85倍;B2F和C3F烟叶中主要Amadori化合物均为1-脱氧-1-L-脯氨酸-D-果糖(Fru-Pro)(14~45 mg/g),其次为1-脱氧-1-L-丙氨酸-D-果糖(Fru-Ala)、1-脱氧-1-L-谷氨酸-D-果糖(Fru-Glu)、1-脱氧-1-L-苯丙氨酸-D-果糖(Fru-Phe)、葡糖胺(GLU)和1-脱氧-1-L-色氨酸-D-果糖(Fru-Trp)(1~20 mg/g)。挖掘出对B2F和C3F烟叶区分贡献较大的化合物,按贡献大小排序为甘露醇>阿洛酮糖>核糖醇>来苏糖>核糖>1-脱氧-1-L-缬氨酸-D-果糖(Fru-Val)>GLU>果糖>Fru-Ala。C3F烟叶各感官质量指标得分均明显高于B2F烟叶。在B2F烟叶中,阿拉伯糖醇、Fru-Pro、阿拉伯糖、木糖醇、阿洛酮糖和Fru-Ala与部分感官评吸指标呈显著或极显著(P<0.01,下同)正相关,Fru-Glu和GLU与部分感官评吸指标呈显著或极显著负相关。在C3F烟叶中,核糖、阿洛酮糖、果糖、葡萄糖和麦芽糖与部分感官评吸指标呈显著或极显著正相关,来苏糖、核糖醇、Fru-Glu和Fru-Phe与部分感官评吸指标呈显著或极显著负相关。【结论】山东烤烟水溶性糖和Amadori化合物的含量在部位间差异明显,进而对烟叶感官质量产生不同的影响。

蓖麻油基聚氨酯薄膜的制备及性能研究

为了探究蓖麻油基聚氨酯(castor oil-based polyurethane,CO-PU)薄膜最佳成膜条件及其综合性能,以蓖麻油(castor oil,CO)、二苯基甲烷二异氰酸酯(4,4-diphenylmethane diisocyanate,MDI)为主要反应物,以过氧化二苯甲酰(benzoyl peroxide,BPO)为自由基引发剂,二月桂酸二丁基锡(dibutyltin dilaurate,DBTDL)为催化剂,控制单一变量,采用预聚体法,制备不同R值(-NCO与-OH物质的量之比)的CO-PU薄膜。探究不同R值、DBTDL含量和成膜固化温度对CO-PU薄膜的力学性能和成膜状态的影响,从而确定CO-PU薄膜的最佳成膜条件。结果表明,当R值为2.5,DBTDL含量为0.1‰,成膜固化温度为80℃时,CO-PU薄膜的抗拉强度和断裂伸长率分别达到36.4 MPa和49.05%,其铅笔硬度达到6H,吸水率为0.01%,水接触角最大为83.5°,有着较好的综合性能。该研究证实了通过改变CO-PU薄膜成膜条件,可以在一定程度上提升CO-PU薄膜的各项性能,为CO-PU薄膜后期的应用拓展以及其他性能研究奠定基础。

环保型聚氨酯防水涂料的制备及性能研究

以水为固化剂,二苯基甲烷二异氰酸酯(MDI)、聚醚多元醇(DL-2000D、MN-3050D)、磺酸盐接枝聚酯二醇(BY-3306)、二羟甲基丁酸(DMPA)和填料等为原料成功合成了一种环保型的水固化聚氨酯防水涂料。讨论了聚醚多元醇种类、亲水扩链剂、气体吸收剂和水的添加量等对涂料性能的影响。结果表明,当聚醚三醇在聚醚混合物中的质量分数为10%、BY-3306替代聚醚二醇DL-2000D质量的15%或DMBA在体系中的质量分数为0.8%、硅酸盐水泥质量分数为8%、NCO基质量分数为4.5%时,得到的防水涂料在添加15%水固化后,拉伸强度可达4.27 MPa,断裂伸长率为678%,撕裂强度为24.57 N/mm。

MICP固化松散砒砂岩抗水蚀机理研究

[目的]探究MICP固化松散砒砂岩效果,为减少砒砂岩区水土流失提供解决方案与理论依据。[方法]从宏观尺度(贯入强度、降雨侵蚀等)探究菌液浓度和固化频次对MICP固化砒砂岩对力学性能及其抗水蚀性能的影响,并在微观尺度(X射线衍射、扫描电子显微镜、傅里叶红外光谱、热分析)解释了砒砂岩固化土的抗水蚀机理。[结果]相同固化次数下菌液浓度(OD_(600))为0.8时固化效果最好,其强度相较其他浓度可提升20%~50%;在最佳菌液浓度0.8时,固化频次为5次时砒砂岩即可获得很好的强度以及抗水蚀性,总雨蚀损失量可降至固化前的10%。菌液浓度0.8时碳酸钙含量生成最多,且多为菱形块状的方解石相,分布更加密集,随着固化次数的增加,胶结及填充效果更好。[结论]细菌及其胞外聚合物(EPS)在MICP中作为成核位点,参与碳酸钙的定位以及生长,并提高了碳酸钙的稳定性;EPS与碳酸钙以及砒砂岩中的矿物形成分子间氢键,增强了碳酸钙的胶结性能,且进一步提高了砒砂岩的强度以及抗水蚀性。