PVP改性PDMS/PAN中空纤维复合膜提升表面亲水性

为了改善气体分离复合膜中聚二甲基硅氧烷（PDMS）过渡层与极性分离层的界面结合,利用高极性的聚乙烯吡咯烷酮（PVP）修饰聚丙烯腈（PAN）中空纤维支撑的PDMS气体分离膜表面,以提高PDMS表面极性和亲水性并减少对气体渗透速率的不利影响. 利用X射线光电子能谱（XPS）证实利用溶液浸渍法可以将PVP接枝在PDMS表面对其修饰,并且随着浸渍时间的增加,PVP接枝量逐步增加,修饰效果逐渐增强. 实验结果表明,交联剂1,3,5-苯三甲酰氯（TMC）增强了PDMS表面的PVP接枝改性,PVP修饰使PDMS表面的水接触角降低到21.1°,显著提高了PDMS表面亲水性和极性,从而有利于PDMS层和极性分离层的紧密结合. PVP修饰使得CO₂对其他气体（H₂、CH₄、N₂）的选择性随TMC/PDMS摩尔比的增加而逐渐降低,气体选择性CO₂/H₂、CO₂/CH₄、CO₂/N₂的最大峰值分别为3.9、3.8、11.8.     

原位共聚改性Mg(OH)2/PP复合材料的微观结构与性能

采用乙烯基硅烷在氢氧化镁晶须（MH）表面引入乙烯基后与不同单体进行原位聚合,制备了改性氢氧化镁晶须（MMH）,通过熔融复合与注射成型的方法制备了聚丙烯/晶须（PP/MH）复合材料,并对复合材料的结构与性能进行了表征.结果表明：原位聚合改性增强了MH与PP之间的界面相互作用力,提高了PP/MH复合材料的冲击强度;填充甲基丙烯酸甲酯（MMA）/丙烯酸丁酯（BA）共单体原位聚合改性MH与MMA原位聚合改性MH相比,PP/MMH复合材料的拉伸强度和冲击强度均有显著提高.     

ZnO/Ag纳米复合材料的硬脂酸改性

以硬脂酸为表面活性剂对采用配合物沉淀法自制的ZnO/Ag纳米复合材料进行了表面改性。系统研究了硬脂酸浓度、用量和改性时间等因素对改性效果的影响,并通过亲油度、接触角、透射电镜、红外及紫外-可见光谱等测试手段,对改性前后的ZnO/Ag纳米复合材料进行了表征。结果表明,采用乙醇加热回流法,用硬脂酸改性ZnO/Ag纳米复合材料能够提高其疏水性及对可见光的吸收能力。硬脂酸改性ZnO/Ag纳米复合材料的优选工艺条件是,硬脂酸浓度为0.010mol.L-1,添加量为10%(质量分数),改性时间为60min。改性后ZnO/Ag纳米复合材料的亲油度为76.47%,接触角为107.8°,其疏水性明显优于未改性材料。     

基于PDMS改性聚氨酯弹性体的合成与表征

以异佛尔酮二异氰酸酯和异佛尔酮二胺为硬链段,聚四氢呋喃多元醇及端羟基聚二甲基硅烷为软段,采用溶液聚合法合成了一系列含不同质量分数PDMS的聚氨酯弹性体。通过傅里叶红外光谱、差示扫描量热法及广角X射线散射等对聚氨酯的形态结构和相分离进行了表征与分析。结果表明,在聚氨酯主链中引入PDMS链段有利于相分离程度的提高。通过凝胶色谱试验、拉伸试验及水接触角测试等,研究了PDMS质量分数的增加对聚氨酯弹性体分子量、形态结构和力学性能的影响。结果表明,随着PDMS质量分数的增加,聚氨酯弹性体的分子量减小,膜的拉伸强度降低,涂膜表面接触角增加。当PDMS占软段的质量分数从0增加至25%时,聚氨酯的拉伸强度从7.57MPa下降到0.64MPa,接触角从72°增大至95°以上。     

具有高PTC转变温度的尼龙12/炭黑复合体系

研究以尼龙12（PA12）为基体树脂、炭黑（CB）为导电填料的高转变温度正温度系数（PTC）材料.采用熔融共混方法制备PA12/CB聚合物PTC复合材料,研究炭黑种类、炭黑含量、热处理、炭黑表面改性等因素对PA12/CB复合材料PTC性能的影响.结果表明：Vxc305炭黑填充PA12复合材料,当炭黑质量分数为30%时PTC效应最好,达到105,转变温度为140℃.炭黑质量分数为40%～50%的复合材料NTC效应基本消除;对PA12/CB复合材料进行热处理能够提高材料PTC强度;炭黑表面改性能够抑制材料的NTC效应.     

石墨烯压阻复合材料及其在裂纹监测中的应用

为了弥补现有柔性应变传感器在健康监测上的不足,以还原氧化石墨烯（rGO）为导电填料,纳米纤维素（CNF）为分散剂和结构骨架,硅橡胶（PDMS）为聚合物弹性基体,采用溶液共混和溶剂挥发法,制备具有压阻效应的弹性复合材料. 对复合材料进行微观结构、力学、电学和机敏性能分析,结果表明,CNF能有效协助rGO在PDMS基体中均匀分散,形成稳定的三维增强和导电网络,提高复合材料的弹性模量和电导率. 当rGO、CNF占PDMS的质量分数分别为10%、3%时,复合材料的弹性模量最大为2.53 MPa,电导率为0.34 S/m. 当复合材料薄膜应变小于10%时,电阻相对变化量与应变呈线性关系,灵敏系数最大为63,对应rGO、CNF的质量分数分别为10%、3%;当应变大于10%时,呈指数变化. 分析复合材料的力电响应机理,将复合材料应用于材料或构件疲劳裂纹的监测中,设计应力强度因子薄膜传感器,并通过理论分析验证其可行性.     

超疏水亲油MTCS/mSiO2/NCC气凝胶的制备与表征

为了制备一种超疏水亲油材料基于纤维素可生物降解的环保特性，采用废棉制备了超疏水亲油的甲基三氯硅烷(MTCS)/mSiO₂/纳米微晶纤维素(NCC)气凝胶。首先将废棉打碎酸解成NCC，再用KH560对SiO₂进行改性，然后以NCC和mSiO₂为原料，制备mSiO₂/NCC复合气凝胶，最后以MTCS为疏水改性剂对m SiO₂/NCC气凝胶改性，制备成超疏水亲油的MTCS/mSiO₂/NCC气凝胶，并使用红外光谱仪、X射线衍射仪、扫描电子显微镜、接触角测试仪，对超疏水亲油材料的形貌、结构及表面浸润进行表征。结果表明：制备得到了一种三维多孔、结果稳定的超疏水亲油MTCS/m SiO₂/NCC气凝胶，静态水接触角最高达150.97°，对食用油、机油和石蜡油的最大吸油倍率分别为60.00 g/g、58.15 g/g和43.27 g/g，能够快速分离油水混合物，具备良好的超疏水亲油性能。     

聚合松香酯化物为交联单体的磁性聚合物微球制备与表征

采用化学沉淀法制备了油酸改性纳米四氧化三铁（Ｆｅ_３Ｏ_４）,并以聚合松香与甲基丙烯酸-β-羟乙酯的酯化物（ＰＲＨ）为交联单体,用悬浮聚合的方法,制备了苯乙烯与ＰＲＨ的磁性聚合物微球。探讨了Ｆｅ_３Ｏ_４的含量对聚合物微球磁性能的影响。用红外光谱、Ｘ射线衍射、Ｘ射线光电子能谱、热重分析、光学显微镜以及振动样品磁强计对磁性聚合物微球进行了表征。结果表明：成功制备了磁性聚合物微球,微球具有超顺磁性;当改性纳米Ｆｅ_３Ｏ_４ 的比例增大时,载入磁性微球中Ｆｅ_３Ｏ_４ 的含量增大,同时磁性微球粒径增大,粒径分布变宽,磁饱和强度增大。     

二氧化硅/聚四氟乙烯疏水海绵的制备

通过溶液浸渍法,用硅烷偶联剂γ-（2,3-环氧丙氧）丙基三甲氧基硅烷对纳米级SiO₂溶胶表面改性,再利用其作为媒介与聚四氟乙烯（PTFE）粒子均匀结合在三聚氰胺海绵（MS）骨架上,热处理后构造微观粗糙疏水结构。用红外光谱、扫描电子显微镜、水接触角对海绵进行了表征。结果表明:SiO₂/PTFE粗糙结构能提高MS的疏水吸油效果,平均静态疏水角达到141°,对柴油、甲苯、四氯化碳等多种油都有较好的吸收效果,其中对四氯化碳的吸收量最高为136 g/g。用改性SiO₂/PTFE-MS吸取水面浮油和水下油滴,油相被改性SiO₂/PTFE-MS快速吸收,容器中水量不变。     

基于动态亚胺键的自修复有机硅弹性体的制备及性能研究

报道了一种将α,ω?氨丙基封端的聚（二甲基硅氧烷）（PDMS?NH₂）、戊二醛（GA）和三（4?氨基苯基）胺（TAPA）通过席夫碱反应进行交联,合成自修复有机硅弹性体PDMS?GA?TAPA。通过FT?IR和¹H?NMR对PDMS?GA?TAPA的结构进行表征。高温溶解实验证明PDMS?GA?TAPA具有优异的化学稳定性和热稳定性。同时,PDMS?GA?TAPA具有优异的机械强度,其拉伸强度最高可达3.6 MPa,断裂伸长率最高可达112%。此外,通过调节PDMS?GA?TAPA的交联密度,可以实现调节PDMS?GA?TAPA机械性能的目的。将PDMS?GA?TAPA样品在100 ℃处理1 h,该弹性体可以实现自修复,其自修复效率达到83%。     

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%.     

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.     

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,...     

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.     

Preparation and mechanical properties of polypropylene fiber reinforced calcined kaolin-fly ash based geopolymer

To improve the environmental benefits and solve the problems of large shrinkage and high brittleness, the partial replacement of calcined kaolin by fly ash as a raw material for geopolymer synthesis and the influences of polypropylene (PP) fiber on the mechanical properties and volume stability were investigated. The results show that compressive strength of the geopolymer containing 33.3%(mass fraction) fly ash by steam curing at 80 °C for 6 d is improved by 35.5%. The 3-day compressive strength, flexural strength and impacting energy of geopolymers containing 0.05%PP fiber increase by 67.8%, 36.1% and 6.25%, while the shrinkage and modulus of compressibility decrease by 38.6% and 31.3%, respectively. The results of scanning electron microscopy (SEM) and the appearances of crack growths confirm that PP fiber can offer a bridging effect over the harmful pores and defects and change the expanding ways of cracks, resulting in a great improvement of strength and toughness. Foundation item: Project(2006AA06Z225) supported by the National High-Tech Research and Development Program of China     

Effects of Cr~(3+), Cu~(2+), and Pb~(2+) on Fly Ash based Geopolymer

The effects of Cr~(3+), Cu~(2+), and Pb~(2+) on compressive strength, reaction products, and pore structures of fly ash based geopolymer were studied. In addition, the immobilization and bonding interaction between heavy metal and fly ash based geopolymers were investigated by X-ray photoelectron spectroscopic(XPS) and environmental scanning electron microscope(ESEM) techniques. The experimental results showed that the incorporation of Cr~(3+), Cu~(2+), and Pb~(2+) had a great effect on the later compressive strength and resulted in producing reinhardbraunsite in the solidified body. Moreover, the Pb~(2+) reduced the total pore volume of the solidified body, while Cr~(3+) and Cu~(2+) increased it. The XPS results indicated that O(1 s), Si(2 p), and Al(2 p)bind energy increased due to Cr~(3+) and Cu~(2+) addition, but it did not change significantly due to Pb~(2+) addition.The microstructure of calcium silicate hydrate(C-S-H) gel and sodium silicoaluminate hydrate(N-A-S-H) gel changed in different degree according to the ESEM results. The immobilization of Cr~(3+), Cu~(2+), and Pb~(2+) using fly ash based geopolymer is attributed not only to the physical encapsulation, but also to the chemical bonding interaction.     

Fly Ash-based Geopolymers:Effect of Slag Addition on Efflorescence

Blended fly ash/blast-furnace slag geopolymers are focused on due to their excellent mechanical and chemical resistant properties. We investigated the effect of slag partial substitution for fly ash on the efflorescence of the resulting geopolymers. The efflorescence of geopolymer binders was inspected and evaluated through leaching tests. The efflorescence deposits on surface of the geopolymer binders were analyzed using XRD and SEM-EDS. The results showed that sodium and calcium cations leached from geopolymer binders reacted with the atmospheric CO_2 and formed the crystal deposits, gaylussite and calcite, in the forms of granular and angular crystal particles. The slag addition led to a refinement of the pore structure of fly ash-based geopolymers, but an increment in the concentration of alkali leaching. The crystal deposits gradually developed in the pore volume of the binders, and finally exceeded the capacity of pore volume. The extent of efflorescence on the surface of specimens increased with the slag substitution. The visible efflorescence is therefore a result of available alkalis and pore sizes and volumes. Higher concentration of available alkalis and smaller pores(and volume) will lead to more intensive efflorescence.     

Static and dynamic leaching experiments of heavy metals from fly ash-based geopolymers

The feasibility of high calcium fly ash (CFA)-based geopolymers to fix heavy metals were studied. The CFA-based geopolymers were prepared from CFA, flue gas desulfurization gypsum (FGDG), and water treatment residual (WTR). The static leaching showed that heavy metals concentrations from CFAbased geopolymers were lower than their maximum concentration limits according to the U.S. environmental protection law. And the encapsulated and fixed ratios of heavy metals by the CFA-based geopolymers were 96.02%–99.88%. The dynamic real-time leaching experiment showed that concentration of Pb (II) was less than 1.1 μg / L, Cr (VI) less than 3.25 mg / L, while Hg (II) less than 4.0 μg / L. Additionally, dynamic accumulated leaching concentrations were increased at the beginning of leaching process then kept stable. During the dynamic leaching process, heavy metals migrated and accumulated in an area near to the solid-solution interface. When small part of heavy metals in “the accumulated area” breached through the threshold value of physical encapsulation and chemical fixation they migrated into solution. The dynamic leaching ratios and effective diffusion coefficients of heavy metals from CFA-based geopolymer were very low and the long-term security of heavy metals in CFA-based geopolymer was safe.     

Effects of Fiber Surface Pretreatment and Composite Post-treatment on Mechanical Properties of 2D-Cf/PhosphateGeopolymer Matrix Composites

$p

纤维表面改性和后处理对2D-碳纤维强韧磷酸盐无机聚合物复合材料力学性能的影响

何培刚^1,2，贾占林^1,2，付帅^1,2，王加涛^1,2，段小明^1,2，杨治华^1,2，贾德昌^1,2，周玉^1,2

（1哈尔滨工业大学 材料科学系，特种陶瓷研究所，哈尔滨 150001；

2 先进结构功能一体化材料与绿色制造技术工信部重点实验室，哈尔滨工业大学，哈尔滨 150001）

中文说明:

无机聚合物因其具有良好的耐热性、阻燃性、环境友好等特性受到广泛关注。然而其主要缺点为强度低、脆性大、应用可靠性差，因此需要对其进行强韧化处理。本文采用超声辅助浸渍法制备了二维连续碳纤维（Cf）增强的磷酸盐基无机聚合物复合材料，通过X射线光电子能谱（XPS），X射线衍射（XRD）和扫描电子显微镜（SEM）研究了纤维表面处理和复合材料高温处理对复合材料性能的影响。结果表明，表面处理可显著改善碳纤维和基体之间的界面相互作用，这在提高复合材料力学性能方面起着关键作用，所制备复合材料的弯曲强度和杨氏模量分别为156.1 MPa和 39.7 GPa，同时其断裂过程完全不同于无机聚合物基体，表现为伪塑性断裂特征，从而使其应用可靠性显著提高。此外，采用后续Sol-SiO2再浸渍处理可提高复合材料致密度从而进一步改善复合材料的力学性能。本文的研究结果提供了一种改善复合材料界面性能的新思路，所制备复合材料表现出较高的力学性能和非灾难性断裂特征，同时具有低温制备、高温服役的突出特性，在高马赫数飞行器多功能防热承载构件上具有潜在的应用前景。

关键词：无机聚合物，碳纤维，复合材料，表面改性，力学性能

     

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.