干湿循环环境下硫酸根对混凝土腐蚀机理研究

在海洋环境中建造的建筑物和构筑物在使用期间常常受到腐蚀介质的侵蚀,引发碱-骨料反应,迚而破坏混凝土结构。为了探究干湿循环环境下硫酸根对混凝土腐蚀机理,减轻混凝土在干湿环境下的腐蚀程度,采用混凝土磨粉机、755B型分光光度计以及借助青岛海水腐蚀实验站迚行实验;从强度等级、混凝土成分以及经济适用等方面迚行考虑,并迚行大量预实验迚行对比,将实验组分为7组,迚行了潮汐区暴露试验和分光光度计测定硫酸根质量分数两个实验。得出在自由硫酸根离子扩散过程中,会在短时间内在临近表面之间存在一个富集带,短时间会阻碍离子的迚一步扩散,并且当离子扩散一定深度之后,浓度保持稳定,不会再发生改变;水胶比的降低降低了混凝土结构紧实程度,促迚了硫酸根离子的扩散。     

Co-Mo系耐硫变换催化剂硫化行为的研究

本文采用程序升温硫化(TPS)技术,对未负载的Co?Mo氧化物和负载在不同载体上的Co和/或Mo系催化剂的硫化过程进行了研究,分析了活性组分Co?Mo在催化剂硫化过程中的形态变化和催化剂的硫化机理,同时还探讨了载体在催化剂硫化过程中的作用。     

一种体相加氢脱硫催化剂的程序升温硫化表征

在全自动化学吸附仪上,用程序升温硫化（TPS）技术对一种体相加氢脱硫催化剂进行表征,考察了金属与载体的相互作用、金属间的相互作用以及焙烧温度对这种催化剂硫化性能的影响。结果表明,MoO3负载于Al2O3载体后,硫化峰温大幅降低,并在TPS谱图中体现出分步硫化的过程,证明MoO3与载体间存在相互作用,形成了易于硫化还原的活性中心。当Mo和Ni共同作用于载体时,形成了更易于硫化的Mo-Ni-O复合相。Co的加入加强了Mo与Ni间的协同作用,Co、Mo、Ni与Al形成了更易硫化的活性中心。W的加入反而改变了硫化中心的性质,使硫化温度提高。对（Mo＋Ni）/Al2O3和（Co＋Mo＋Ni）/Al2O3催化剂,于500℃焙烧时,催化剂硫化性能最好。最后得出结论：当Co、Mo、Ni 3种金属共同作用于载体,并于500℃焙烧时,其硫化中心活性最高。     

汽油加氢精制MoP催化剂制备的研究

按照Mo∶P摩尔比为1,称取2.729 g磷酸氢二铵((NH4)2HPO4)和3.65 g钼酸铵((NH4)6Mo7O24·4H2O)混合溶于去离子水中,采用氢等离子体还原法(PR)制备免焙烧的MoP催化剂。通过X射线衍射对磷化钼催化剂迚行表征。以二苯幵噻吩(DBT)/十氢萘溶液为加氢脱硫(HDS)反应模型化合物迚行催化反应活性评价。通过实验数据说明,PR法成功制备了体相MoP催化剂,且催化剂的颗粒尺寸较小,具有较高的DBT加氢脱硫反应活性。     

加氢催化剂的器外预硫化技术研究

加氢催化剂硫化的预处理过程是决定催化剂活性和选择性的重要环节。采用气相硫化技术在小型固定床流化反应器上对加氢催化剂进行器外预硫化的研究，通过N₂吸附、TEM、TG-DTA、XRD和H₂-TPR等技术对处理后的催化剂进行表征。结果表明,不同的硫化方法对催化剂中硫的质量分数和活性均有很大影响。预硫化后的催化剂中硫的质量分数高，活性好。     

载体性质对耐硫变换催化剂硫化性能的影响

利用程序升温硫化（TPS）技术考察了四种不同类型载体的耐硫变换催化剂的硫化性能，结果发现,载体性质是影响催化剂硫化性能的重要因素，在载体中添加特种助剂，能显著提高催化剂的易硫化性能，降低硫化温度。     

丙烷催化脱氢制丙烯工艺及催化剂的研究进展

综述了目前世界上丙烷催化脱氢制丙烯的工艺及其迚展,主要包括Oleflex工艺、Catofin工艺、STAR工艺、PDH工艺和FBD工艺。对比了这五种常用工艺方法的基本特点,描述了国内丙烷脱氢制丙烯项目的开工及产能情况,介绍了各种工艺的基本情况,幵对相兲的催化剂迚行了简述。在此基础上,对丙烷催化脱氢制丙烯工艺和相兲催化剂迚行了展望。     

预硫化型CoMo加氢脱硫催化剂性能

采用等体积浸渍方法制备CoMo催化剂,选用不同预硫化方法制备一系列硫化型CoMo催化剂,考察反应温度和空速对加氢脱硫性能的影响,并与对比剂进行比较。结果表明,硫化型CoMo催化剂在不同温度和空速下,具有较好活性,在200 h周期实验中,硫化型CoMo催化剂表现出良好的稳定性,脱硫率98.7%。TEM表征显示,硫化型CoMo催化剂具有更多的MoS_2堆垛层,形成更多高活性Co-Mo-SⅡ型活性相。     

硫化温度对CoMo/Al_2O_3加氢处理催化剂的影响

本文就CoMoAl_2O_3加氢处理催化剂、硫化过程相关影响因素、脱硫活性因素等的关系展开研究,通过对TEM方法、XPS方法等就催化剂状况展开表征。通过结果得知,硫化温度的提升,会提高催化剂的硫化度状况及载硫量。伴随着硫化温度的改变,催化剂的活性逐渐发生改变,逐渐向高活性Co-Mo-S转变。当硫化温度处于410℃时,催化剂呈现出高活性的特点。经过大量的实验得知,硫化温度环境的变化,催化剂的脱硫活性变化曲线表现出先升后降的趋势,催化剂在330℃时其脱硫活性最高。     

恒温硫磺回收反应器局部过热成因分析与改造

天然气净化脱硫脱碳装置胺再生产的酸性气,需要迚行达标处理并回收硫磺,硫磺回收可以很好地处理含H_2S酸气。对于本装置产生的低浓度酸性气,使用常规的克劳斯工艺难以达到硫回收的技术要求,因此采用直接氧化法。采用流体仿真软件Fluent对反应器迚行了流场仿真模拟分析,并对反应时反应器内的温度、压力、流线等参数迚行了计算,通过对比分析反应器不同结构下的仿真计算结果,最终确定使用该反应器的结构和参数。针对该厂反应器存在的问题,对该厂的反应器迚行了流场仿真,仿真模型涵盖了迚气口、触媒反应区域、出气口;根据催化剂参数以及反应数据仿真分析,计算初步算例、反应发生程度以及放热量。利用CFD迚行整个流场的仿真分析,寻找理论超温点。通过优化流场以及反应器结构设计,并对整流装置以及触媒筐组件设计,根据流体压强改变反应器局部渗透率,使反应气能平稳的通过反应器间隙及催化剂床层,保证反应气速均匀分布,保证流场条件满足催化剂技术指标。同时通过加装混合格栅,实现反应气浓度在催化剂中均匀分布,保证硫化氢的催化氧化反应均匀迚行。并通过混合格栅的优化设计,使反应气温度分布均匀。     

Properties of thermoplastic starch and TPS/polycaprolactone blend reinforced with sisal whiskers using extrusion processing

Sisal whiskers (SW) were prepared by acid hydrolysis for subsequent evaluation as reinforcing material for biodegradable matrices of thermoplastic starch (TPS) and TPS/polycaprolactone (TPS/PCL) blends. The acid hydrolyzed SW had dimensions of 5 ± 2 nm in diameter and 210 ± 60 nm in length and 78% crystallinity. The nanocomposite blends consisted of whisker contents of 5 and 10 wt% and were coextruded with either TPS or TPS/PCL which formed the matrix material. The influence of SW on the morphology, crystallinity, thermal properties, mechanical behavior, structural, and biodegradation of TPS and TPS/PCL matrices were investigated. The lower SW content of 5 wt% dispersed and interacted well with both matrices. The introduction of PCL in the TPS matrix leads to an increased crystallinity and there was evidence that the carbonyl groups of PCL interacted with the OH groups on the surface of the whiskers. Addition of PCL decreased the whisker/whisker interaction over TPS alone, favoring the dispersion of the whiskers in the matrix and, consequently, the reinforcement effect was more pronounced in TPS/PCL blends than in the pure TPS matrix. The addition of the whiskers as reinforcement increased the biodegradability of TPS and TPS/PCL matrices. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers.     

苹果酸对聚乳酸/热塑性淀粉共混物结构与性能的影响

将天然淀粉用甘油改性后制得了热塑性淀粉(TPS),再通过熔融共混法制备了聚乳酸(PLA)/TPS共混物。通过SEM、TG、DSC分析和拉伸性能、吸水性能、流变性能测试,研究了苹果酸对TPS和PLA/TPS共混物结构和性能的影响。结果表明:苹果酸能促进淀粉酸解,使TPS分散相尺寸减小,在PLA基体中的分布更加均匀;苹果酸能提高PLA/TPS共混物的拉伸性能;苹果酸对PLA/TPS共混物的玻璃化转变温度、熔融温度及冷结晶温度影响较小;少量的苹果酸可降低PLA/TPS共混物的吸水率。     

Utilization of ramon seeds (Brosimum alicastrum swarts) as a new source material for thermoplastic starch production

The development and characterization of biodegradable polymers deriving from renewable natural sources has attracted much attention. The aim of this work was to partially characterize a thermoplastic starch obtained from the starch of seeds from the ramon tree (TPS‐RS) as an option to substitute thermoplastic starch from corn (TPS‐CS), in some of its applications. At 55% of relative humidity (RH), TPS‐RS had higher tensile strength and deformation than TPS‐CS. X‐ray diffraction analysis showed similar values in residual crystallinity (percentage of crystallinity that remains after plasticization process) in both TPS. The SEM micrographs showed a few remnant granular structures in the TPS‐RS. The FTIR showed a greater intensity in band at 1016 cm^?1 in the TPS‐CS and TPS‐RS in comparison with their corresponding native starch, indicating an increase in the amorphous region after plasticization. The TGA analysis showed greater thermal stability in TPS‐CS (340 °C) compared with TPS‐RS (327 °C). In addition, the glass transition temperature in both TPS was 24 °C. The results obtained represent a starting point to potentialize the use of TPS‐RS instead of TPS‐CS for the development of new biodegradable materials for practical applications in different areas. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44235.     

Biodegradability,mechanical, and thermal properties of thermoplastic starch/cuttlebone composites

This work focused on improvements to the properties of thermoplastic starch (TPS) by using cuttlebone (CB) as the bio‐filler. The effect of CB on the properties of TPS was compared to that of commercial calcium carbonate (CC). The good adhesion achieved between the TPS matrix and the cuttlebone powder produced improvements in the tensile strength of their composites, whereas the tensile strength of TPS/CC composite was lower due to the presence of filler agglomerates. The biodegradation of the TPS and the composites were analyzed by the soil burial test. This showed that cuttlebone decreased the biodegradation rate. The thermal degradation temperatures of TPS, a TPS/CC composite and a TPS/CB composite showed very similar behavior. POLYM. COMPOS., 36:1401–1406, 2015. © 2014 Society of Plastics Engineers     

Microstructural characterization of corn starch‐based porous thermoplastic composites filled with multiwalled carbon nanotubes

Microstructural characterization of corn starch‐based porous thermoplastic (TPS) composites containing various contents (0.1, 0.5, and 1 wt %) of multiwalled carbon nanotubes (MWCNTs) was performed. Corn starch was plasticized with a proper combination of glycerol and stearic acid. TPS composites with MWCNT were prepared conducting melt extrusion followed by injection molding. TPS containing 1 wt % of MWCNTs exhibited higher tensile strength and elastic modulus values than neat TPS. Moreover, TPS electrical conductivity was determined to increase with increasing content of MWCNTs. X‐ray diffraction measurements revealed that incorporation of MWCNTs increased the degree of TPS crsystallinity to some extent. Scanning electron microscopy examination revealed that MWCNT altered TPS surface morphology and tensile failure modes, significantly. Transmission electron microscopy investigation showed that dispersion characteristics of MWCNTs within TPS were in the form of tiny clusters around micro pores of TPS, which is considered influential on electrical conductivity of the resulting composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of Morphology on the Biodegradation of Thermoplastic Starch in LDPE/TPS Blends

In this study, thermoplastic starch (TPS) was mixed with low density polyethylene with different melt flow indexes in a one-step extrusion process to produce LDPE/TPS blends varied from 32% to 62% by weight of TPS. The influence of starch content and LDPE viscosity on morphology, biodegradation and tensile properties of LDPE/TPS blends were evaluated. Starch continuity and biodegradability were studied by hydrolytic, enzymatic and bacterial degradation. The LDPE viscosity had a considerable effect on the morphology and the connectivity of the starch particles. Evaluation of hydrolytic extraction showed that blends having TPS content above 50 wt% possessed a full connectivity. Studies of biodegradation indicated that the bacterial attack on starch resulted in weight loss of TPS of 92%, 39% and 22%, for PE1/TPS having 62% and 32% TPS, and PE2/TPS (31% TPS), respectively. Comparatively, the weight loss was more significant at 100%, 66% and 31% by hydrolytic extraction. Differences between these two techniques were discussed in terms of the accessibility of starch domains to microorganisms. Tensile properties (ε_b and E) decreased with increasing exposure time to activated sludge. Changes in tensile properties were highly dependent on the biodegradation rate. PE1/TPS blends having 32% starch remained ductile after 45 days of exposure to bacterial attack.     

Preparation and Properties of Biodegradable Thermoplastic Starch/Clay Hybrids

Biodegradable thermoplastic starch (TPS)/clay hybrids were prepared by melt intercalation. Three organically modified montmorillonite (MMT) with different ammonium cations and one unmodified Na⁺ MMT (Cloisite Na⁺) were used. Cloisite Na⁺ showed the best dispersion in the TPS matrix. It was observed that the TPS/Cloisite Na⁺ hybrid showed an intercalation of TPS in the silicate layer due to the matching of the surface polarity and interactions of the Cloisite Na⁺ and the TPS, which gives higher tensile strength and better barrier properties to water vapor as compared to the other TPS/organoclay hybrids as well as the pristine TPS. It was found that the dynamic mechanical properties of the TPS/clay hybrids were also affected by the polar interactions.     

改性TPS对PPC基复合材料流变、微观形貌和力学性能的影响

分别以无水醋酸锌(ZA)和酒石酸(TA)作为热塑性淀粉(TPS)的改性剂,通过熔融共混法制备了改性TPS及聚甲基乙撑碳酸酯(PPC)/改性TPS复合材料,并采用旋转流变仪、傅里叶变换红外光谱仪、扫描电子显微镜、热重分析仪、差示扫描量热仪等分析表征了改性TPS对复合材料流变行为、微观形貌和力学性能的影响.结果表明,与ZA...     

TPS／PBAT共混体系的结构、性能和形态研究

通过熔融共混制备了系列TPS／PBAT复合材料,研究了TPS含量对TPS／PBAT结构、力学性能、耐热性能和微观形态的影响,结果表明：PBAT可以明显提高TPS的拉伸强度、断裂伸长率和耐热温度,但TPS和PBAT两相相容性较差。     

Mechanical and thermal properties of wood fibers reinforced poly(lactic acid)/thermoplasticized starch composites

Thermoplasticized starch (TPS) filled poly(lactic acid) (PLA) blends are usually found to have low mechanical properties due to poor properties of TPS and inadequate adhesion between the TPS and PLA. The purpose of this study was to investigate the reinforcing effect of wood fibers (WF) on the mechanical properties of TPS/PLA blends. In order to improve the compatibility of wood with TPS/PLA blends, maleic anhydride grafted PLA (MA‐g‐PLA) copolymer was synthesized and used. TPS, TPS/PLA blends, and WF reinforced TPS/PLA composites were prepared by twin‐screw extrusion and injection molded. Scanning electron microscope and crystallinity studies indicated thermoplasticity in starch. WF at two different weight proportions, that is, 20% and 40% with respect to TPS content were taken and MA‐g‐PLA at 10% to the total weight was chosen to study the effect on mechanical properties. At 20% WF and 10% MA‐g‐PLA, the tensile strength exhibited 86% improvement and flexural strength exhibited about 106% improvement over TPS/PLA blends. Increasing WF content to 40% further enhanced tensile strength by 128% and flexural strength by 180% with respect to TPS/PLA blends. Thermal behavior of blends and composites was analyzed using dynamic mechanical analysis and thermogravimetric analysis. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46118.