A New DOPO-Eugenol Adduct as an Effective Flame Retardant for Epoxy Thermosets with Improved Mechanical Properties

The development of efficient green flame retardants is an important way to realize more sustainable epoxy thermosets and downstream materials.In this work,a monoepoxide is synthesized through O-glycidylation of eugenol,and then reacted with DOPO(9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide)to obtain a new bio-based flame retardant,DOPO-GE.DOPO-GE is blended with a bisphenol A epoxy prepolymer exhibiting good compatibility and DDS(4,4′-diaminodiphenylsulfone)is used as the curing agent to afford epoxy thermosets.Although DOPO-GE leads to the reduced glass transition temperature of the thermosets,the storage modulus increases considerably.The DOPO-GE-modified thermosets exhibit the high thermal stability with the onset thermal decomposition temperature in nitrogen and air exceeding 300℃.When the phosphorus content in the thermoset is 1.0%,the residual yield of the thermosets at 750℃ in nitrogen increases from 13.9%to 30.6%,due to the increased charring ability.More interestingly,when the phosphorus content is only 0.5%,the limiting oxygen index is as high as 30.3%with UL94 V0 achieved.Cone calorimeter results reveals the significantly decreased heat release rate,total heat release,mass loss and total smoke production.Furthermore,DOPO-GE can notably improve the flexural strength,flexural modulus and fracture toughness,whereas the shear and impact strength are reduced to varied extents.In short,DOPO-GE can be obtained via a facile way,and shows the good flame-retardant effect on the epoxy thermosets with an application potential.

EFFECTS OF Pb COMPOUND ADDITIVES ON THE PROPERTIES OF YBa_2Cu_3O_(7-δ)

The melting temperature and critical transition temperature Tc of YBa2Cu3O7-δ with deferent content additives of PbO and BaPbO3 were studied. When PbO was doped in YBa2Cu3O7-δ, the melting temperature of YBa2Cu3O7-δ was reduced, however its superconductivity was weakened. From the XRD pattern of the sintered mixture of YBa2Cu3O7-δ and PbO, it was known that there was a reaction between YBa2Cu3O7-δ and PbO, and the product was BaPbO3. Hence different contents of BaPbO3 (10mass%, 20mass% and 30mass%) were added in YBa2Cu3O7-δ. It was proved that there were no reactions between YBa2Cu3O7-δ and BaPbO3. And the superconductivity of the mixtures was much better than that of the samples with PbO additive.

Grain selection and growth orientation of prior-β phase for Ti-6-4 during additive manufacturing:insights from a modeling perspective

The microstructure of Ti-6-4 components produced by additive manufacturing suffers from the coarse and elongated prior-β grain,which leads to a decrease of the tensile behavior and the occurrence of anisotropy.To understand and control the grain evolution,a multiscale simulation is applied to investigate the relationship between the grain selection,growth orientation,and the molten pool morphology with the different deposition layer numbers and processing parameters.The accuracy of the simulation is validated by experiments in both qualitative and quantitative ways.Results show that when the grain with unfavorable orientation loses the competitive growth with its neighbors,there will be a great chance that the blocked grain is eliminated in the following layer-and-layer deposition,which leads to the increase of the grain width.The size of the molten pool increases remarkably as the layer number increases,which lays a heavy burden on the stability of the molten pool.The analytical relationship between the molten pool morphology and the grain growth orientation is also deduced.The flat molten pool causes the grains with the <001> direction close to the building direction to have greater survival potential.Besides,decreasing the line power energy shows little effect on the stability of the molten pool and the grain growth orientation,especially when the deposited layer number is large.The revealing mechanisms will help in understanding and further controlling the grain evolution.

Flame Retardants Nanocomposites-Synergistic Effect of Combination Conventional Retardants with Nanofillers of the Flammability of Thermoset Resins

The consumption ofthermoset resins as building polymers is approximately over one million tone word wide. The thermoset resins are proven construction materials for the technical and highly demanding applications of the transportation, electrical and building part industry. Heat stability, high thermal, low shrinkage, excellent mechanical properties are typical for their type of polymers. Above applications in addition to the mechanical properties also require good flame retardants of the materials. Undertaken activities refer to official draft, laws and legal recommendations in UE states. This paper presents positive effect of reduced flammability of thermoset resins （unsaturated polyester and epoxy resins） thanks to the use of nanocomposites containing multi-ingredient halogen-flee flame retardants which combine conventional phosphorus/nitrogen modifiers interacting with nanofillers （oMMT （organomodified montmorillonite）, EG （expandable graphite）, graphene, GO （graphene oxide）, nSi （nanosilica））.

Anti-Bacterial and Flame Retardant for Cotton Fabric by One-Bath Finishing

A research on the process of cotton fabric flame-re-tarding,anti-bacterial finishing and one-bath finish-ing of anti-bacterial and flame-retarding is discussed.The flame retardant agent was phosphorous-contained,and the bacteriostatic finishing agent named SFR-1 wassynthesized.The flame retardancy of the fabric finishedcan meet the DOC FF3-71 Children Sleepwear Stan-dard.Its bacterial inhibiting capacity can meet and ex-ceed the requirements of similar products

Analyzing the Interplay of Sintering Conditions on Microstructure and Hardness in Indirect Additive Manufacturing of 17-4PH Stainless Steel

Indirect additive manufacturing(AM)methods have recently attracted attention from researchers thanks to their great potential for cheap,straightforward,and small-scale production of metallic components.Atomic diffusion additive manufacturing(ADAM),a variant of indirect AM methods,is a layer-wise indirect AM process recently developed based on fused deposition modeling and metal injection molding.However,there is still limited knowledge of the process conditions and material properties fabricated through this process,where sintering plays a crucial role in the final consolidation of parts.Therefore,this research,for the first time,systematically investigates the impact of various sintering conditions on the shrinkage,relative density,microstructure,and hardness of the 17-4PH ADAM samples.For this reason,as-washed samples were sintered under different time-temperature combinations.The sample density was evaluated using Archimedes,computed tomography,and image analysis methods.The outcomes revealed that sintering variables significantly impacted the density of brown 17-4PH Stainless Steel samples.The results indicated more than 99% relative densities,higher than the value reported by Markforged Inc.(~96%).Based on parallel porosities observed in the computed tomography results,it can be suggested that by modifying the infill pattern during printing,it would be possible to increase the final relative density.The microhardness of the sintered samples in this study was higher than that of the standard sample provided by Markforged Inc.Sintering at 1330℃ for 4 h increased the density of the printed sample without compromising its mechanical properties.According to X-ray diffraction analysis,the standard sample provided by Markforged Inc.and“1330℃—4 h”one had similar stable phases,although copper-rich intermetallics were more abundant in the microstructure of reference samples.This study is expected to facilitate the adoption of indirect metal AM methods by different sectors,thanks to the high achievable relative densities reported here.

Investigation of the Transition Reaction of Tobermorite to Xonotlite under Influence of Additives

The objective of the present work was to investigate the transition reaction of the calcium silicate hydrate tobermorite into xonotlite under influence of additives. Tobermorite is the main binding agent in steam hardened building materials and the appearance of xonotlite indicates the progress of hardening and an overcuring of the material. Hydrothermal experiments under addition of sucrose, calcium formate and calcium chloride dihydrate to the main components quartz and lime were done using temperatures of 220°C and a reaction time of 40.5 h. All experiments were performed with powders as well as with pressed educts. The products of all syntheses were analyzed with XRD, SEM/EDX and FTIR. The references as well as the syntheses with calcium chloride dihydrate led to the formation of 11 &#197 tobermorite and xonotlite. The former showed the best results and even synthesis with pressed educts and calcium chloride dihydrate revealed an accelerating effect of the additive. In contrast syntheses with sucrose had the worst reactivity and led to the formation of calcite beside the CSH-phase scawtite. The additive calcium formate was only slightly oppressing the crystallization of tobermorite and favouring the formation of xonotlite. Syntheses with pressed pellets and sucrose or calcium formate showed generally worse results.

矿用MDI-50型聚氨酯加固材料的制备及性能研究

聚氨酯注浆加固材料在煤矿井下使用过程中需保证其力学强度及降低材料注浆过程的反应温度,因而针对添加阻燃剂和通过化学反应以改变材料结构的阻燃改性方法研究极其重要。为了有效提升聚氨酯加固材料力学性能和阻燃性能,在聚氨酯加固材料B组分中引入异氰酸酯和扩链剂预聚工艺,有效合成MDI-TMP加成物,从而整体提高硬段交联程度。通过红外光谱、万能力学试验机和热重、凝胶渗透色谱研究预聚温度对MDI-50型聚氨酯加固材料力学性能和阻燃性能的影响。研究结果表明:最高反应温度、抗压强度和拉伸强度随预聚反应温度增加而升高,预聚温度为80℃时所制得的聚氨酯加固材料力学性能最佳;极限氧指数主要由阻燃剂添加量决定,预聚体的结构对其影响不大。MDI-50型聚氨酯加固材料的反应速率可调,反应温度上升平缓,凝结后具有较高的力学性能,可满足聚氨酯注浆材料在煤矿加固应用的要求。

The Reductive Addition Reaction of Substituted 2-Chloromethyl-1,3,4-oxadiazole to Aldehydes and Ketones Promoted by Samarium Diiodide

1-（β-Hydroxyalkyl）-l,3,4-oxadiazole derivatives were synthesized via reductive addition reactions of 2-chloromethyl-l,3,4-oxadiazole with carbonyl compounds under mild conditions promoted by SmI2.

Effect of TiO2 Addition on Slag Resistance of Lightweight Corundum-spinel Castables

Five lightweight castables containing different TiO2 additions were prepared by using porous corundum - spinel （ MgAl2O4 ） ceramics as aggregate. Corrosion of the lightweight cstables by ladle slag was conducted using a static crucible test. The effect of the TiO2 addition on the slag resistances of the lightweight corundum -spinel castables was investigated through SEM, EDS and Fact- Sage@ software, etc. h was found that TiO2 additi,ve t,vmoted the sintering degree of the castables, deereased the average pore .size, the apparent porosity, and the contact area between the casmbles and slag, and then en- hanced the corrosion resistance. However, TiO2 additive decreased the viscosity of the penetrated .slag simultane- ously, and then deteriorated the penetration resistance.

Effect of Pelletized Graphite Addition on Properties of Al_2O_3-SiC-C Castables

Al2O3 - SiC - C castables with pelletized graphite addition of 0. 2%, 4% or 6% （by mass, the same hereinafter ） were prepared using brown fused corundum （8 - 5, 5 - 3 and 3 - 1 mm ） , dense fused corundum （ ≤1 and 0. 045 mm） and SiC （ ≤1 and ≤0. 064 mm） its main starting materials with mass ratio of aggregate： matrix = 71： 29, 2% silicon powder and 0. 4% B4C as antioxidants, and pelletized graphite as carbon source, Effect of pelletized graphite addition on physical properties, oxidation resistance, slag resistance arid thermal shock resistance of Al2O3 -SiC- C eastables was researched. The results show that： with the in.crease of pelletized graphite addition, the required water amount of castables increases, the bulk density and strength reduce; with 4% pelletized graphite, the eastable performs the best oxidation resistance; the increase of graphite is beneficial to the improvement of slag penetration resistance and corrosion resistance; with 6% pelletized graphite, the thermal shock resistance is the best.

磷-氮阻燃剂在环氧树脂中的应用研究进展

环氧树脂在许多工业领域具有广泛应用,但其高度的易燃性容易导致火灾,对环氧树脂进行阻燃改性具有重要研究意义。基于对绿色环保的要求越来越高,无卤、低毒、低烟的新型磷-氮阻燃剂的制备仍是目前环氧树脂阻燃研究的热点。本文对近五年国内外研究者们应用添加型和反应型磷-氮阻燃剂对环氧树脂的改性研究进行分类介绍,以期为环氧树脂的阻燃研究提供参考。

腰果酚基阻燃高分子材料研究进展

随着全球环保意识的提高和国家碳达峰战略的提出,利用可再生生物基资源制备阻燃高分子材料受到广泛关注。腰果酚来源广泛、价格低廉,具有多个高活性反应基团,有望用于商业化制备阻燃高分子材料。本文综述了用于改性聚氯乙烯、不饱和聚酯和环氧树脂的腰果酚基阻燃添加剂的制备方法,同时对比分析了其性能。总结归纳了阻燃腰果酚基环氧树脂、阻燃腰果酚基苯并噁嗪、阻燃腰果酚基紫外光固化涂层、阻燃腰果酚基聚氨酯泡沫和阻燃腰果酚基酚醛泡沫的最新研究进展。指出制备综合性能优异的多功能阻燃腰果酚基高分子材料是未来研究的重点方向。

添加剂对水泥混凝土耐久性能的改善机理研究

旨针对添加剂对水泥混凝土耐久性能的改善机理展开研究,通过分析水泥混凝土的组成和结构特点,以及矿物掺合料、缓凝剂和膨胀剂对水泥混凝土性能的影响,揭示了改善水泥混凝土耐久性的关键因素。分别探讨了矿物掺合料、缓凝剂和膨胀剂对水泥混凝土耐久性能的影响与作用机理,矿物掺合料影响了水泥混凝土的流动性、力学性能、抗渗性、抗冻性和收缩性能;缓凝剂对水泥混凝土的流动性、强度、干缩性能和抗渗性能产生影响;膨胀剂则影响了水泥混凝土的力学性能、抗渗性能、抗碳化性能、抗硫酸盐侵蚀性能以及抗冻融循环性能。

硬质聚氨酯泡沫材料用无卤阻燃剂的研究进展

聚氨酯常用卤系阻燃剂存在燃烧时释放卤化氢腐蚀性气体及有毒有害物质的问题,危害人体健康。近年来,无卤阻燃剂以无卤、低烟、环保的优势,已逐渐替代卤系阻燃剂用于硬质聚氨酯泡沫阻燃。该文介绍了添加型阻燃剂和反应型阻燃剂最新研究进展,重点概括了添加型无机阻燃剂(如金属氢氧化物及氧化物、无机磷系、无机硅系及其协同阻燃剂、纳米材料)、添加型有机阻燃剂(如有机氮系、有机磷系、有机硅系及有机硅系及其协同阻燃剂)、膨胀型阻燃剂(可膨胀石墨、氮、磷膨胀型阻燃剂)及含氮、磷、硅的反应型阻燃剂的特点、阻燃机理及其对硬质聚氨酯泡沫阻燃性能的影响;对聚氨酯泡沫用无卤阻燃剂阻燃机理进行了阐述;最后,对聚氨酯泡沫用无卤阻燃剂今后发展的热点进行了展望。

具有吸附作用的酸液缓速外加剂FL-1的研制

针对目前常规酸液缓速外加剂普遍存在泵入地层困难,二次伤害大等问题,从分子结构出发,合成了一种具有吸附作用的酸液缓速外加剂。采用CO2气体采集装置对外加剂延缓酸岩反应性能和缓速酸液的黏度进行了评价。结果表明,外加剂质量分数为0.5%时,缓速时间为140 min,酸液初始黏度为4.5 m Pa·s;酸岩反应过程中随着盐质量浓度和转子转速的逐渐增大,酸液缓速外加剂仍具有较好的缓速效果,并且外加剂与其他处理剂配伍性良好。

油井水泥缓凝剂SDH-2的性能研究及应用

为满足深井固井对水泥缓凝剂的特殊要求,研制出了一种高温耐盐缓凝剂SDH-2.该缓凝剂由碱、醛、亚磷酸制备,具有工艺简单、成本低的特点.介绍了SDH-2的制备条件,考察了反应物配比和催化剂加量对产品性能的影响,并在室内评价了SDH-2的缓凝性能、耐温抗盐性能、配伍性能以及对水泥石抗压强度的影响.结果表明:SDH-2在40～170 ℃的范围内具有优良的缓凝效果,缓凝时间可调性好,稠化曲线理想,抗盐性良好,与降失水剂、减阻剂有良好的相容性,对油井水泥选择性小,水泥石抗压强度高.SDH-2在现场应用了6口井,结果表明:该缓凝剂解决了深井固井中水泥浆稠化性能不稳定,稠化时间难以控制的问题,水泥浆具有良好的流动性能,满足不同井眼条件下固井对水泥浆流动性能的要求;同时水泥浆抗压强度发展迅速,高温条件下水泥石性能稳定,符合深井固井的要求.

油井水泥高温缓凝剂DZH-2室内评价与应用

高温缓凝剂DZH-2是一种高效油井水泥缓凝剂,通过加入水泥浆中调整其稠化时间,水泥浆综合性能良好,水泥浆配方和性能易于调节,保证了固井施工安全,减少了水泥浆对油气层的污染,有效改善了水泥石胶结质量,提高了固井质量。该缓凝剂克服了国内目前缓凝剂存在的技术问题和不足之处,适用温度范围宽,在浅井、中深井和深井中均可应用;适用于各种级别的油井水泥,可与多种外加剂配伍;可在多种水质中应用,可用于多类固井作业等,在海上、西北、西南、东北等多个油田和地区应用,取得了良好的固井效果,具有广阔推广应用前景。

抗高温缓凝剂GH-ⅡB在中原油田固井中的应用

针对高温高压深井固井中发生的问题,中原油田采用了加有抗高温缓凝剂GH-ⅡB的水泥浆体系。该缓凝剂是有机多糖化合物经深度氧化后生成的液态物质,其羧基官能团能吸附在水化物表面形成保护膜,并抑制水化物与水接触,减缓水化物晶核的生成,从而降低水泥颗粒的水化速度。室内试验表明,抗高温缓凝剂GH-ⅡB具有较高的热稳定性,对水泥有良好的缓凝特性和一定的减阻能力,可适用于95-160℃的高温区域,稠化曲线近似呈直角;可形成早期强度,减少失重危害,并与其它外加剂配伍性良好。抗高温缓凝剂GH-ⅡB经在40多口探井和深井使用,效果良好,固井合格率达99%,优良率在80%以上。

粉煤灰磁珠对环氧树脂聚合物阻燃性能的影响

为了实现粉煤灰固体废弃物的资源化利用,从粉煤灰中分选出元素含量不同的磁珠(MSs),探究MSs添加量和MSs中Fe元素含量对环氧树脂(epoxy resin,EP)阻燃性能的影响。采用锥形量热仪(CC)、热重分析(TG)等测试手段对MSs/EP复合材料的阻燃性能进行测试。研究结果表明:随着粒径减小,磁珠中的Fe元素含量从55.73%升高至64.83%。当MSs添加量分别为2 wt%,4 wt%,6 wt%,8 wt%和10 wt%时,复合材料的耐火性能先升高后下降;当MSs中Fe元素含量分别为55.73%,57.06%,60.35%和64.83%时,复合材料的耐火性能单调升高。与纯EP相比,当MSs添加量为6 wt%,Fe元素含量为64.83%时,MSs/EP复合材料的热释放速率峰值p-HRR降低39.6%,总热释放量THR降低30.7%,火灾性能指数FPI提高53.73%,阻燃指数FRI从1提高至3.118,火灾增长指数FGI降低51.96%,残炭率提高47.5%。MSs/EP良好的阻燃性能主要归因于MSs能够催化EP形成连续稳定的炭层,从而隔绝热量和氧气,降低复合材料的燃烧强度。研究结果可提高粉煤灰磁珠的高附加值利用,同时为低成本阻燃聚合物提供参考。