Compressive Performance of Fiber Reinforced Recycled Aggregate Concrete by Basalt Fiber Reinforced Polymer-Polyvinyl Chloride Composite Jackets

The development of recycled aggregate concrete(RAC)provides a new approach to limiting the waste of natural resources.In the present study,the mechanical properties and deformability of RACs were improved by adding basalt fibers(BFs)and using external restraints,such as a fiber-reinforced polymer(FRP)jacket or a PVC pipe.Samples were tested under axial compression.The results showed that RAC(50%replacement of aggregate)containing 0.2%BFs had the best mechanical properties.Using either BFs or PVC reinforcement had a slight effect on the loadbearing capacity and mode of failure.With different levels of BFs,the compressive strengths of the specimens reinforced with 1-layer and 3-layer basalt fiber reinforced polymer(BFRP)increased by 6.7%–10.5%and 16.5%–23.7%,respectively,and the ultimate strains increased by 48.5%–80.7%and 97.1%–141.1%,respectively.The peak stress of the 3-layer BFRP-PVC increased by 42.2%,and the ultimate strain improved by 131.3%,relative to the control.This reinforcement combined the high tensile strength of BFRP,which improved the post-peak behavior,and PVC,which enhanced the structural durability.In addition,to investigate the influence of the various constraints on compressive behavior,the stress-strain response was analyzed.Based on the analysis of experimental results,a peak stress-strain model and an amended ultimate stress-strain model were proposed.The models were verified as well;the result showed that the predictions from calculations are generally consistent with the experimental data(error within 10%).The results of this study provide a theoretical basis and reference for future applications of fiber-reinforced recycled concrete.

PARTICLE MORPHOLOGY OF POLY(VINYL CHLORIDE)RESIN PREPARED BY SUSPENDED EMULSION POLYMERIZATION

Suspended emulsion polymerization was used to prepare poly(vinyl chloride) (PVC) resin. Fine PVC particleswere formed at low polymerization conversions. The amount of fine panicles decreases as conversion increases anddisappears at conversions greater than 30%. Scanning electron micrographs show that PVC grains are composed of looselycoalesced primary particles, especially for PVC resins prepared in the presence of poly(vinyl alcohol) dispersant. The size ofprimary particles increases and porosity decreases with the increase of conversion. In view of the particle features of PVCresin, a particle formation mechanism including the formation of primary particles and grains is proposed. The formationprocess of primary particles includes the formation of particle nuclei, coalescence of particle nuclei to form primary particles,and growth of primary particles. PVC grains are formed by the coagulation of primary particles. The loose coalescence ofprimary particles is caused by the colloidal stability of primary particles and the low swelling degree of vinyl chloride in the primary particles.

Preparation and characterization of organic polymer modified composite polyaluminum chloride

Compared with traditional aluminum salts, polyaluminum chloride （PACI） has better coagulation-flocculation performance in turbidity removal. However, it is still inferior to organic polymers in terms of bridging function. In order to improve the aggregating property of PACl, different composite PACl flocculants were prepared with various organic polymers. The effect of organic polymer on the distribution or Al（Ⅲ） species in composite flocculants was studied using ^27TAl NMR and Al-ferron complexation methods. The charge neutralization and surface adsorption characteristics of composite flocculants were also investigated. Jar tests were conducted to evaluate the turbidity removal efficacy of organic polymer modified composite flocculants. The study shows that cationic polymer and anionic polymer have significant influences on the coagulation-flocculation behaviors of PACl. Both cationic and anionic polymers can improve the turbidity removal performancc of PACl but the mechanisms arc much different： cationic organic polymer mainly increases the charge neutralization ability, but anionic polymer mainly enhances the bridging function.

Influence of Suspended Emulsion Polymerization Conditions on Particle Characteristics of Polyvinyl Chloride Resin

Suspended emulsion polymerization of vinyl chloride was carried out in a 5 L autoclave. The influence of agitation, polymerization conversion, dispersant and surfactant on the average particle size (PS) and particle size distribution (PSD), particle morphology and porosity of polyvinyl chloride (PVC) resin was investigated. It showed that the agitator had great influence on the smooth operation of polymerization, PS and PSD. The PS increased and PSD became narrow as polymerization conversion became high. The porosity decreased with the increase of conversion. A convenient choice of additives, both dispersants and non-ionic surfactants, allows one to adjust PS and PSD. The PS decreased with the addition of polyvinyl alcohol or hydroxypropyl methylcellulose dispersants,and increased with the addition of Span surfactants. The addition of dispersants or surfactants also affected the morphology and porosity of resin, and PVC resin with looser agglomeration and homogeneous distribution of primary particles was prepared.

Preparation of Thin Film Composite Nanofiltration Membrane by Interfacial Polymerization with 3,5-Diaminobenzoylpiperazine and Trimesoyl Chloride

A new aromatic diamine,3,5-diaminobenzoylpiperazine （3,5-DABP）,was synthesized from 3,5-diaminobenzoic acid and 1-formyl piperazine.The structure of 3,5-DABP was identified by FT-IR spectra and 1H NMR spectra.With 3,5-DABP as aqueous monomer and trimesoyl chloride （TMC） as organic monomer,thin film composite （TFC） nanofiltration membranes were prepared by interfacial polymerization technology.The salt rejection order of these TFC membranes is Na2SO4MgSO4MgCl2NaCl.This sequence indicates that the membranes are negatively charged.

THE EFFECT OF MONOMERS FEEDING METHODS ON EMULSION COPOLYMERIZATION OF VINYLIDENE CHLORIDE AND ACRYLATES

The emulsion copolymerization of vinylidene chloride (VDC) with methyl-methacrylate(MMA) and acrylonitrile (AN) was carried out by batch, seeded batch and semicontinuous pro-cesses,respectively. Significant differences were found in the physical and mechanical propertiesof the latexes and films, depending on the methods of monomer feeding. The results both intheory and experiments demonstrated that the copolymer composition and the length of the VDC sequences in the copolymer could be controlled by the modes of monomer feeding process.

Sodium chloride methanol solution spin-coating process for bulk-heterojunction polymer solar cells

The sodium chloride methanol solution process is conducted on the conventional poly（3-hexylthiophene）（P3HT）/[6,6]-phenyl-C61-butyric acid methyl ester（PC_（61）BM） polymer bulk heterojunction solar cells. The device exhibits a power conversion efficiency of up to 3.36%, 18% higher than that of the device without the solution process. The measurements of the active layer by x-ray photoelectron spectroscopy（XPS）, atomic force microscopy（AFM）, and ultraviolet photoelectron spectroscopy（UPS） indicate a slight phase separation in the vertical direction and a sodium chloride distributed island-like interface between the active layer and the cathode. The capacitance–voltage（C–V） and impedance spectroscopy measurements prove that the sodium chloride methanol process can reduce the electron injection barrier and improve the interfacial contact of polymer solar cells. Therefore, this one-step solution process not only optimizes the phase separation in the active layers but also forms a cathode buffer layer, which can enhance the generation, transport, and collection of photogenerated charge carriers in the device simultaneously. This work indicates that the inexpensive and non-toxic sodium chloride methanol solution process is an efficient one-step method for the low cost manufacturing of polymer solar cells.

Kinetics of Vinyl Chloride Polymerization with Mixture of Initiators

Kinetic models for the rate constants of vinyl chloride polymerization in the presence of initiator mixtures were proposed. They may be used to design the initiator recipes for the vinyl chloride polymerization with uniform rate at different temperatures at which various grades of poly(vinyl chloride) will be prepared.

PS-HQ:More convenient in situ polymeric cocatalyst for the PdC1_2-catalyzed acetalization in supercritical carbon dioxide

Polystyrene-supported hydroquinone （PS-HQ） is presented as an in situ polymeric cocatalyst to replace polystyrenesupported benzoquinone （PS-BQ） in the PdCl2-catalyzed acetalization of methyl acrylate with methanol in supercritical carbon dioxide （scCO2） under oxygen atmosphere. Due to deletion of H2O2 oxidation step, PS-HQ is more convenient and relatively inexpensive.

UV enhanced gas–solid synthesis of chlorinated poly vinyl chloride characterized by a UV–Vis online analysis method

Dynamic characteristics of UV enhanced gas–solid PVC chlorination process were revealed by a UV–Vis spectral online analysis method. Experimental results showed an instantaneous increase of the chlorination rate as soon as UV light was affiliated, which demonstrated the intensified effect of UV radiation on PVC chlorination directly.Different affiliation methods of UV light were then studied, proving that continuous UV radiation could enhance the chlorination process significantly while intermittent UV radiation was able to initiate the chlorination reaction once it was conducted. Besides, experiments were carried out to study the influences of parameters on the chlorination process such as UV wavelength, chlorination temperature, partial pressure of chlorine gas and PVC raw materials. Among all the parameters, chlorination temperature and partial pressure of chlorine gas were testified as two key factors to determine the chlorination performance. Thermal analysis of CPVC products showed that their corresponding properties such as the glass transition temperature(Tg) and the homogeneity of chlorine distribution in polymer phase were improved with the increase of chlorine content.

Effect of Chloride Content on Bond Behavior Between FRP and Concrete

For reinforced concrete structures located along the seaside, the penetration of chloride ions into concrete may be a threat to the durability of the structures. Experimental investigations were carried out to study the effect of chloride content on the bond behavior between concrete and fiber reinforced polymer (FRP) plates. Direct shear tests were conducted on the FRP strengthened concrete members. Before testing, the specimens were immersed in NaCl solutions with concentrations ranging from 3%—15% for di...

Experimental Investigation on Contribution of CFRP Attachment to Durability of Reinforced Concrete Structure Subjected to Chloride Attack

The function of externally-bonded carbon fiber reinforced polymer （CFRP） in preventing chloride from entering into concrete is verified by experiment. The results show that externally-bonded CFRP can be considered as a part of corrosion prevention system of strengthened concrete structures subjected to chloride ingress, and the contribution of CFRP should be considered in evaluation of durability of reinforced concrete structures with externally-bonded CFRP. With the effective shielding function of CFRP considered, an equation for residual lifetime prediction of concrete structures with externally-bonded CFRP is derived from Fick＇s dispersion law. CFRP has two functions for coastal concrete structures, including strengthening and increasing durability as part of corrosion prevention system.

铁尾矿酸浸液制备聚氯化铁的试验研究

为探索某选矿厂铁尾矿回收利用的新途径,对铁尾矿酸浸液制备聚氯化铁的试验过程进行了研究,并将自制的聚氯化铁应用到高岭土悬浊液的混凝试验中测试产品的絮凝性能。结果表明:聚合的适宜条件为温度为40℃、pH为1.0、聚合时间为3h,在该条件下合成的聚氯化铁盐基度为20.91%,符合相关标准,影响聚合过程因素的主次顺序依次为聚合温度、pH、聚合时间;混凝的适宜条件为聚氯化铁投加量为250 mg/L、pH为7.0、搅拌时间为3min、温度为20℃、混凝时间为60min,在该条件下浊度去除率为95.54%,产品除浊效果良好。

丙烯酰胺/甲基丙烯酰氧乙基三甲基氯化铵的水分散聚合物制备

以丙烯酰胺(AM)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)为共聚单体,过硫酸铵为引发剂,自制聚甲基丙烯酰氧乙基三甲基氯化铵(PDMC)为分散剂,在硫酸铵水溶液中采用水分散聚合法,制备了丙烯酰胺/甲基丙烯酰氧乙基三甲基氯化铵共聚水分散体.考察了分散聚合过程中体系黏度变化,引发剂用量、硫酸铵的用量、分散剂的用量对共聚物黏度、分子量、颗粒尺寸的影响,并对其结构进行了鉴定.实验发现,在30℃,AM、DMC总单体质量分数为15%,DMC与AM物质的量比为1∶9,过硫酸铵浓度范围为0.70×10^(-4)~2.8×10^(-4)mol/L,硫酸铵质量分数范围为26.51%~28.1%,分散剂PDMC质量分数范围为1.1%~1.3%条件下,可以制备出黏度低、稳定性好的丙烯酰胺/甲基丙烯酰氧乙基三甲基氯化铵共聚水分散体.

聚丙烯酰氧乙基二甲基苄基氯化铵的合成

以偶氮二异丁基脒盐酸盐(V-50)为引发剂,丙烯酰氧乙基二甲基苄基氯化铵(DMBC)为聚合单体,采用自由基水溶液聚合法,在氮气氛围中制备了阳离子型聚丙烯酰氧乙基二甲基苄基氯化铵(PDMBC)。用单因素法考察了单体质量分数、引发剂用量、反应温度以及反应体系pH对聚合物黏度和相对分子质量的影响。对反应条件进行了优化,当反应温度为42℃时,可以合成出相对分子质量100万以上的聚丙烯酰氧乙基二甲基苄基氯化铵。

丙烯酰胺/丙烯酰氧乙基二甲基苄基氯化铵共聚水分散体的制备

以丙烯酰胺(AM)、丙烯酰氧乙基二甲基苄基氯化铵(DMBC)为共聚单体,过硫酸铵为引发剂,自制聚甲基丙烯酰氧乙基三甲基氯化铵(PDMC)为分散剂,在硫酸铵水溶液中采用水分散聚合法,制备了丙烯酰胺/丙烯酰氧乙基二甲基苄基氯化铵共聚水分散体。考察了反应温度、硫酸铵浓度、单体配比、链转移剂浓度、分散剂用量、引发剂用量对共聚物黏度、相对分子质量、颗粒尺寸的影响。实验发现,制备丙烯酰胺/丙烯酰氧乙基二甲基苄基氯化铵共聚水分散体较优配方为:温度65℃,硫酸铵质量分数为27.6%,AM、DMBC总单体质量分数为15%,DMBC∶AM(质量比)=(0.297~0.363)∶1,链转移剂用量为0.078 g/L,分散剂质量分数2.7%~3.6%,过硫酸铵质量分数范围为4.38×10^(-4)~5.84×10^(-4)mol/L。

N⁃苯基马来酰亚胺共聚物的合成及对PVC树脂耐热改性效果研究

通过种子乳液聚合结合半连续加料方式,成功聚合出分子结构一致且与聚氯乙烯(PVC)树脂具有良好相容性的聚(N‐苯基马来酰亚胺‐苯乙烯‐丙烯腈)(PNSA)共聚物胶乳,将其与PVC树脂直接复合制备PNSA/PVC复合材料,并对PNAS耐热改性的效果进行评价。结果表明,PNSA纳米胶乳颗粒粒径在155.3~251.5 nm之间,粒径分布均一;PNSA共聚物分子组成呈无规结构,分子结构一致,差示扫描量热曲线呈现单一的玻璃化转变温度(T_(g)),且与PVC树脂具有极佳的相容性;PNSA含量由0升高至50%(质量比,下同)时,复合材料的T_(g)由84.8℃提高到107.2℃,提高了22.4℃,维卡软化温度由71.2℃提高到91.9℃,提高了20.7℃;除耐热性改善以外,复合材料的力学性能也有一定程度的提高,本文的研究有利于PVC应用领域的进一步拓展。

赤泥用于酸性含锰废水中锰的净化研究

采用还原焙烧-磁选预处理赤泥,得到非磁性物;非磁性物经煅烧、盐酸溶出后加入饱和偏铝酸钠聚合剂聚合后过滤、熟化制备聚合氯化铝(PAC)基液;使用该PAC基液,在沉降时间5 h、PAC基液与废水体积比1∶120、搅拌转速140 r/min、pH值8、反应温度30℃、聚丙烯酰胺(PAM)投加量20 mg/L条件下处理含锰酸性废水,处理后液中锰质量浓度由325.3 mg/L降至1.5 mg/L,锰去除率达99.5%,净化后液中锰质量浓度达到国家一级排放标准。

石蜡Pickering乳液及其微胶囊相变非织造材料的制备与性能

Pickering乳液固含量和储存稳定性等性能显著优于传统乳液,但是,其乳化剂品种仍然稀缺,以苯乙烯(St)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)为主要单体,二乙烯基苯(DVB)为交联剂,乙醇为助溶剂,用无皂乳液聚合法制备了阳离子型共聚物颗粒(P(St-co-DMC)),并将其作为乳化剂制备了石蜡Pickering乳液;并将石蜡乳液浸渍粘胶水刺非织造布制备石蜡微胶囊相变材料(Vis-PCM)。借助红外光谱仪、扫描电子显微镜、热重/差热联用仪、差示扫描量热仪和接触角测量仪等对共聚物及相变材料微观结构与性能进行表征与测试。实验结果表明:随着DMC用量、引发剂用量和乙醇含量的增加,单体转化率先增大后减小,P(St-co-DMC)粒径和分散指数先减小后增大,其Zeta电位则先快速增大而后趋于恒定,而亲水性持续增强;所得石蜡Pickering乳液的油水体积比高达3∶1,储存稳定性超过3个月;Vis-PCM的相变潜热高达139.3 J/g,经过20次冷热循环处理后,Vis-PCM中的石蜡泄漏率仅0.6%。本文制备的Vis-PCM具有良好的储热与放热性能,在相变储能领域具有广阔的应用前景。