Synthesis and heavy metal immobilization behaviors of fly ash based gepolymer

Two aspects of studies were carried out: 1) synthesis of geopolymer by using fly ash and metakaolin; 2) Immobilization behaviors of fly ash based geopolymer in a presence of Pb and Cu ions. As for the synthesis of fly ash based geopolymer, 4 different fly ash content (10%, 30%, 50%, 70%) and 3 types of curing regimes (standard curing, steam curing and autoclave curing) were investigated to obtain the optimum synthesis condition based on the compressive and flexural strength. The experimental results show that geopolymer, containing 30% fly ash and synthesized at steam curing (80° for 8 h), exhibits higher mechanical strengths. The compressive and flexural strengths of fly ash based geopolymer reach 32.2 MPa and 7.15 MPa, respectively. Additionally, Infrared (IR) and X-ray diffraction (XRD) techniques were used to characterize the microstructure of the fly ash geopolymer. IR spectra shows that the absorptive band at 1086 cm⁻¹ shifts to lower wave number around 1033 cm⁻¹, and the 6-coordinated Al transforms into 4-coordination during the synthesis of fly ash based geopolymer. The resulting geopolymeric products were X-ray amorphous materials. As for immobilization of heavy metals, the leaching tests were employed to investigate the immobilization behaviors of the fly ash based geopolymer synthesized under the above optimum condition. The leaching tests showed that fly ash based geopolymer can effectively immobilize Cu and Pb heavy metal ions, and the immobilization efficiency reached 90% greater when heavy metals were incorporated in the fly ash geopolymer in the range of 0.1% to 0.3%. The Pb exhibits better immobilization efficiency than the Cu, especially in the case of large dosages of heavy metals.     

Strength and Microstructural Analysis of Geopolymer Prepared with Recycled Geopolymer Powder

The strength and microstructural analysis of recycled geopolymer are presented in this paper.Five kinds of geopolymers containing 0%,20%,50%,80% and 100 % of recycled geopolymer powder were prepared using metakaolin as the source material.The alkali activator solution was a mixture of sodium silicate (Na_2SiO_3) and 12 M sodium hydroxide (NaOH).The change laws of compressive and flexural strength of recycled geopolymer specimens were investigated.And the microscopic characteristics were carried out by SEM,XRD and FTIR to observe the internal morphology and analyze changes in components of recycled geopolymers at different substitution rates.The results show that,with the increase of substitution rate of recycled geopolymer powder,the mechanical properties of recycled geopolymers degenerate and the looser structure are formed.When the substitution rate is less than 50%,the recycled geopolymer specimen meets the use requirements of heavy traffic load class.And the specimen with 80% of substitution rate satisfies the requirements of plastering mortar.     

Pore Size Distribution of High Performance Metakaolin Concrete

The Compressive strength, porosity and pore size distribution of high performance metakaolin (MK) concrete were investigated. Concretes containing 0,5%,10% and 20% metakaolin were prepared at a water/cementitious material ratio (W/C) of 0.30.In parallel, concrete mixtures with the replacement of cement by 20% fly ash or 5 and 10% silica fume were prepared for comparison.The specimens were cured in water at 27℃ for 3 to 90 days .The results show that at the early age of curing(3 days and 7 days),metakaolin re-placements increase the compressine strength ,but silica fume replacement slightly reduces the compressine strength.At the age of and after 28 days ,the compressive strength of the concrete with metakaolin and silica fume replace-ment increases.A strong reduction in the total porosity and average pore diameter were observed in the conctete with MK 20% and 10% in the first 7 days.     

Preparation of a Novel Cationic Photosensitive Resin(3D-SLR01) for Stereolithography 3D Printing and Determination of Its Some Properties

A novel cationic photosensitive resin(3 DSLR-01) for stereolithography 3 D printing was prepared with 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate(2021 P),1,4-cyclohexanedimethanol glycidyl ether(JX-026), diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate(S-186), polycaprolactone polyol(Polyol-0305), novolac epoxy resin(F-51), bis(3-ethyl-3-oxetanylmethyl) ether(S-221) and a mixture of triarylsulfonium hexafluoroantimonate salts solution(UVI-6976). The properties of the photosensitive resin and its UV-cured films were investigated by some instruments and equipment.The experimental results show that the critical exposure(Ec) of the photosensitive resin is 16.3 mJ/cm~2, the penetration depth(D_p) is 0.14 mm, and the optical property of the photosensitive resin is excellent. Rectangle plates were printed by using a stereolithography apparatus(HRPL-150 A) with the photosensitive resin as the manufacturing material, and the shrinkage rates of the plates were less than 0.60%, which showed that the accuracy of the manufactured plates was very high.     

增强型地质聚合物的制备

为了改善地质聚合物的力学性能,采用偏高岭土为原料,液体水玻璃和氢氧化钠作为碱激发剂,三聚磷酸铝为促进剂,制备了增强型地质聚合物. 对增强型地质聚合物进行了X-射线衍射、扫描电子显微镜、热失重分析、抗压强度等表征,研究促进剂对地质聚合物结构和抗压强度的影响. 结果显示促进剂参与了聚合反应,并且进入到地质聚合物的结构中,使地质聚合物的凝胶相向颗粒状转变;而且,促进剂的加入显著提高了地质聚合物的抗压强度. 与未加促进剂的地质聚合物的77 MPa抗压强度相比,当添加0.5%的促进剂,增强型地质聚合物的抗压强度为156 MPa,增加了102.6%.     

钛酸钾晶须改性偏高岭土基多孔地质聚合物的制备与性能

为提高多孔地质聚合物的力学强度和隔热性能,分别以双氧水（H2O2）和十二烷基硫酸钠（SDS）为发泡剂和稳泡剂,采用化学发泡法制备了由钛酸钾晶须改性的偏高岭土基多孔地质聚合物材料,对其进行了微观结构表征及性能测试。结果表明,当发泡剂和稳泡剂质量分数分别为2.0%和1.5%时,孔结构分布均匀,总孔隙率最高可达51.6%,平均孔径为0.87 mm,其抗压强度为3.63 MPa;随着钛酸钾晶须质量分数从0.0%增至10.0%时,其最高抗压强度可达4.11 MPa。在钛酸钾晶须质量分数为20%时,其最低导热系数可达0.048 W/（m?K）,相比于空白样,抗压强度提高了13.22%,导热系数降低了80.80%。钛酸钾晶须的引入可以明显提高多孔地质聚合物的抗压强度和隔热性能。     

Structural characteristics and properties of PU-modified TDE-85/MeTHPA epoxy resin

Diglycidyl-4,5-epoxycyclohexane-1,2-dicarboxylate (TDE-85)/methyl tetrahydro-phthalic anhydride (MeTHPA) epoxy resin was modified by polyurethane(PU), and its structural characteristics and properties were studied by infrared spectrum analysis (IR), scanning electronic microscopy (SEM), mechanics testing and thermogravimetric analysis (TG). The results indicate that epoxy polymeric network I and polyurethane polymeric network II are formed in the PU-modified TDE-85/MeTHPA epoxy resin. Meanwhile the PU-modified TDE-85/MeTHPA resins have heterogeneous structure. The miscibility between epoxy (EP) and polyurethane (PU) as well as the phase size are dominantly determined by the mass fraction of polyurethane prepolymer (PUP) in the EP/PU blends. With the increase of PUP mass fraction, the tensile strength, impact strength and thermal stability of the PU-modified TDE-85/MeTHPA epoxy resin all firstly exhibit increasing tendency, and decrease after successively reaching their maxima. When the number-average molecular mass of PPG is 1 000 and the mass fraction of PUP is 15%, the tensile strength, impact strength and thermal stability of materials obtained, compared with TDE-85/MeTHPA epoxy resin, are improved obviously.     

天然胶/杜仲胶共混硫化物结晶性对热致形变回复性能的影响

用XRD法分析天然胶/杜仲胶共混硫化胶的结晶性,研究其结晶性对天然胶/杜仲胶共混硫化胶的物理性能和热致形变性能的影响.实验结果表明:随着杜仲胶用量的增加,硫化胶在XRD图谱中的衍射峰强度增大,硫化胶的结晶性增大,硫化胶交联密度有明显减小.定伸应力和拉伸强度随杜仲胶用量的增加而增大,而拉断伸长率减小,热致回复温度降低,试样的最终形变率减小.     

铝硅磷质胶凝材料结合耐火浇注料的制备及性能研究

探讨了采用偏高岭土基磷酸盐胶凝材料作粘结剂用于硅酸铝质耐火材料的制备及其高温性能,采用XRD、SEM等测试方法研究了偏高岭土、锆英石对硅酸铝质耐火材料性能的影响.研究结果显示：当偏高岭土的掺量为15%时,在1 300℃下处理3 h后其抗压强度可达79.4 MPa,并且其线收缩率仅为0.1%,具有较好的高温稳定性;用少量的锆英石替代铝矾土熟料可提高材料的高温性能,当其掺量达到9%时,在1 300℃下热处理后材料的抗压强度达到96.8 MPa.     

粉煤灰-矿渣基地聚物混凝土力学性能与微观结构

为考察不同配合比对地聚物混凝土性能的影响,开展了粉煤灰与矿渣比例、水玻璃模数以及水玻璃掺量(质量分数)对其宏观力学性能影响的实验研究,并从微观层次扫描电子显微镜(SEM)、能量弥散X射线分析(EDS)、X射线衍射(XRD)、傅里叶红外光谱(FT-IR)以及压汞实验(MIP)对微观结构进行研究.结果表明:养护龄期的增加,...     

Preparation of A Novel Hybrid Type Photosensitive Resin for Stereolithography in 3D Printing and Testing on the Accuracy of the Fabricated Parts

A novel hybrid type photosensitive resin for stereolithography in 3D printing was prepared with bisphenol A type epoxy diacrylate (EA-612), tripropylene glycol diacrylate (TPGDA),ethoxylated trimethyolpropane triacrylate(EO_3TMPTA), cycloaliphatic diepoxide(ERL-4221),polycaprolactonepolyol(Polyol-0301),1-hydroxy-cyclohphenyl ketone(Irgacure184), and a mixture of triarylsulfonium hexafluoroantimonate salts (Ar_3SS_bF_6). The novel hybrid type photosensitive resin was the photosensitive resin of an epoxy-acrylate hybrid system, which proceeded free radical polymerization and cationic polymerization in ultraviolet (UV) laser. Cuboid parts and double-cantilever parts were fabricated by using a stereolithography apparatus with the novel hybrid type photosensitive resin as the processing material,and the dimension shrinkage factor and the curl factor were tested. The shrinkage factor was less than 2.00%,and the curl factor was less than 8.00%, which showed that the accuracy of the fabricated parts was high with the photosensitive resin for stereolithography in 3D printing.     

螺环结构膨胀单体的合成及膨胀性能研究

为解决环氧树脂固化时体积收缩带来的不良影响,用实验室合成的三元醇与二正丁基氧化锡反应制得螺环结构的膨胀单体3,9-二羟甲基-3,9-二(二甲基乙硫基)-1,5,7,11-四氧杂螺环[5,5]十一烷改性环氧树脂.产物经红外、核磁表征其结构.用膨胀剂跟踪测定阳离子引发膨胀单体开环聚合体积膨胀率为3.16%,考察预聚体改性环氧树脂体积膨胀率的变化,为1.194%.     

环氧-酚醛-聚酰胺树脂掺混清漆

应用溶解度参数理论,通过对环氧树脂、聚酰胺树脂、酚醛树指３种树脂均相溶液的适当掺混,并对各种清漆配方性能测试比较,造反出附着力好、抗冲击强度好、耐酸耐碱等化学腐蚀性强等综合性能优良的溶剂型环氧－酚醛－聚酰胺树脂清漆。其适宜配方（ｗＢ）为：Ｅ－４４环氧树脂３０．５２％,低分子聚酰胺树脂１０．２６％,酚醛树脂１０．２７％,邻苯二甲酸二丁酯３．５１％,二甲苯／环乙酮（质量比１／１）８．９４％,二甲苯／正     

玄武岩纤维布增强环氧树脂复合材料研究

以玄武岩纤维平纹布 (BF) 加入到环氧树脂 (EP) 中,采用模压工艺制备BF／EP 复合材料,研究加入不同层数的玄武岩纤维布对复合材料力学性能和断裂韧性的影响。实验结果表明,BF/EP复合材料的弯曲强度、冲击强度和断裂韧性明显优于环氧树脂;与未加BF的环氧树脂相比,加入三层BF后复合材料的弯曲强度提高了2.76倍,缺口冲击强度提高了19.67倍,无缺口冲击强度提高了5.94倍,KIC提高了2.97倍。     

端异氰酸酯基聚醚接枝环氧树脂的性能研究

合成了端异氰酸酯基聚醚（ITPs）改性双酚A型环氧树脂，通过红外光谱（IR）、动态热机械分析（DMA）研究了ITPs和EP之间的化学反应及改性环氧树脂酸酐固化体系的热性能，并测试了固化体系的力学性能。结果表明：ITPs作为枝链接枝到环氧树脂上：随着加入ITPs质量分率增加，其固化体系的冲击强度和弯曲强度上升，当ITPs含量为10％时，两者达到最大值：动态热机械分析（DMA）结果表明改性环氧树脂固化体系的玻璃化转变温度（Tg）随ITPs的含量增大而降低：当ITPs质量分率大于15%时，过量的ITPs与改性环氧树脂会形成相分离。     

Preparation of fly ash and rice husk ash geopolymer

The geopolymer of fly ash (FA) and rice husk ash (RHA) was prepared. The burning temperature of rice husk, the RHA fineness and the ratio of FA to RHA were studied. The density and strength of the geopolymer mortars with RHA/FA mass ratios of 0/100, 20/80, 40/60, and 60/40 were tested. The geopolymers were activated with sodium hydroxide (NaOH), sodium silicate, and heat. It is revealed that the optimum burning temperature of RHA for making FA-RHA geopolymer is 690℃. The as-received FA and the ground RHA with 1%-5% retained on No.325 sieve are suitable source materials for making geopolymer, and the obtained compressive strengths are between 12.5-56.0 MPa and are dependent on the ratio of FA/RHA,the RHA fineness, and the ratio of so dium silicate to NaOH. Relatively high strength FA-RHA geopolymer mortars are obtained using a sodium silicate/NaOH mass ratio of 4.0, delay time before subjecting the samples to heat for 1 h, and heat curing at 60℃ for 48 h.     

环氧树脂用作不锈钢管表面应变片防水材料的可靠性试验研究

在对土体中不锈钢管桩身应变测量时,环氧树脂常常被用于应变片的防水,然而环氧树脂在空气中或者受水作用时呈现低收缩性,该收缩应变往往会对桩身真实应变带来一定误差。另外环氧树脂剪切强度和开裂应变较低,其受到偶然外力作用时可能会剥离不锈钢管,同时剥离包含其中的应变片,这会导致部分测点失测,这两个细节有时会被忽视。文章实测环氧树脂在空气中和受水作用时给不锈钢管表面应变片带来的收缩应变,与钢管表面的裸片应变进行对比,分析环氧树脂应用于该情况时的可靠性。     

基于紧密堆积理论的环氧混凝土配合比设计

基于紧密堆积理论，采用MAA模型和Fuller最大密度理论选出了砂石骨料的最优级配，应用正交试验方法确定了环氧混凝土的最佳配合比，并进行了力学性能评价和微观分析。结果表明：砂石骨料经级配优化后，紧密堆积空隙率明显降低，最紧密堆积空隙率仅为22.23％。骨胶比对环氧混凝土劈裂抗拉强度具有显著性影响，水泥适合作为填料掺入环氧混凝土中。环氧混凝土的立方体抗压强度随龄期的增长而略有增长，且与环氧树脂的固化程度紧密相关，当环氧树脂完全固化时，环氧混凝土的立方体抗压强度基本不再随龄期而变化。经级配优化后，环氧混凝土的力学性能得到改善，立方体抗压强度有所提高。通过SEM微观测试分析发现，级配优化后的环氧混凝土内部有害缺陷明显减少，体系密实均匀，内部黏结力更强。     

改性醋丙乳液无醛免烫剂的合成及应用

以醋酸乙烯酯、苯乙烯、丙烯腈为主要原料,合成了性能稳定的核壳型聚醋酸乙烯酯乳液无醛免烫剂,通过红外光谱(FTIR)验证了醋丙共聚物的结构。结果表明,此醋丙乳液整理后织物水洗后DP级达3级,强力损失下降19%,白度下降5.6%。将醋丙乳液与甲醚化改性的N,N-羟甲基-4,5-二羟基乙烯脲(DMDHEU)树脂复配,对纯棉织物进行免烫整理的用量优化为:醋丙乳液50g/L,DMDHEU树脂30g/L,氯化铵3g/L,整理后织物的DP级达3.5级,缩水率<1%,布面释放甲醛未检出。     

Strength of copolymer grouting material based on orthogonal experiment

Using the orthogonal experimental design method involving three factors and three levels, the flexural strength and the compressive strength of copolymer grouting material were studied with different compositions of water-cement ratio (mass fraction of water to cement), epoxy resin content, and waterborne epoxy curing agent content. By orthogonal range and variance analysis, the orders of three factors to influence the strength, the significance levels of different factors, and the optimized compound ratio scheme of copolymer grouting material mixture at different curing ages were determined. An empirical relationship among the strength of copolymer grouting material, the water-cement ratio, the epoxy resin content, and the waterborne epoxy curing agent content was established by multivariate regression analysis. The results indicate that water-cement ratio is the most principal and significant influencing factor on the strength. Epoxy resin content and waterborne epoxy curing agent content also have a significant influence on the strength. But epoxy resin content has a greater influence on the 7-day and 28-day flexural strength, and waterborne epoxy curing agent content has a greater influence on the 3-day flexural strength and the compressive strength. The copolymer grouting material with water-cement ratio of 0.4, epoxy resin content of 8% (mass fraction) and waterborne epoxy curing agent content of 2% (mass fraction) is the best one for repairing of cement concrete pavement. The flexural strength and the compressive strength have good correlation, and the ratio of compressive strength to flexural strength is between 1.0 and 3.3. Foundation item: Projects(40728003, 40772180, 40802064) supported by the National Natural Science Foundation of China; Project (07JJ4012) supported by the Hunan Provincial Natural Science Foundation of China; Project(20080430680) supported by China Postdoctoral Science Foundation; Project(B308) supported by Shanghai Leading Academic Discipline Project