UV固化MWNT-P-MER/PUA纳米阻燃材料的制备

为改善UV固化聚氨酯丙烯酸酯(PUA)涂层的阻燃及热稳定性,对多壁碳纳米管(MWNTs)进行有机化改性,制备了一种含有N、P、Si三种阻燃元素于一体的新型碳纳米管阻燃单体(MWNT-P-MER);并经UV固化制备了两类MWNTs/PUA纳米材料,即MWNTs/PUA和MWNT-P-MER/PUA纳米材料。同时对样品热稳定性及阻燃性进行了测定分析,结果表明,两类材料的热稳定性及阻燃性均得到改善;MWNT-P-MER对PUA纳米材料的热稳定性及阻燃性能改善效果更显著。当MWNT-P-MER的添加量为10.7%时,可以得到综合性能最佳的MWNT-P-MER/PUA纳米材料:双键转化率达80%,极限氧指数(LOI)为33.2,UL-94燃烧级别达到V-0级,最终残炭率为20.7%,峰热释放速率为462kW/m2。     

石墨烯/黑磷纳米复合粒子对环氧树脂阻燃与热稳定性能的影响

近年来,具有蜂窝状褶皱片层结构的黑磷(BP)在阻燃高分子复合材料领域展现出潜在的应用前景.本工作采用高能球磨方法制备出石墨烯/黑磷纳米复合粒子(G-BP),以拉曼光谱与X射线衍射表征其结构,并利用极限氧指数(LOI)、UL 94垂直燃烧测试和热重分析探究G-BP含量对环氧树脂基体热稳定性与阻燃性能的影响.结果表明:在环氧树脂中添加2％G-BP,其高温残炭量从14.8％提高至25.3％,LOI提高至25.5％,且UL 94垂直燃烧等级达到V1级;G-BP添加量为5％时,环氧树脂的LOI达27.5％,且UL 94垂直燃烧等级通过V0级.G-BP通过气固双相阻燃协同机理,明显改善了环氧树脂的成炭性与阻燃性.     

三聚氰胺氰尿酸盐与聚磷酸铵协同作用对环氧树脂阻燃性能的影响

采用氧指数法（LOI）、垂直燃烧法（UL-94）及热重分析法（TGA）对三聚氰胺氰尿酸盐（MCA）和聚磷酸铵（APP）阻燃环氧树脂的阻燃性及热稳定性进行了研究。TGA结果表明,MCA促进成炭的作用较弱,主要在气相起到阻燃的作用。而APP的添加虽然降低了环氧树脂的初始分解温度,但当温度高于400℃时,体系具有更好的热稳定...     

二乙基次膦酸铝与三嗪成炭剂协同阻燃PBT的研究

采用二乙基次磷酸铝(AlPi)复配超支化三嗪大分子成炭剂(EA)对聚对苯二甲酸丁二醇酯(PBT)进行无卤阻燃改性。通过氧指数、UL-94垂直燃烧及锥形量热测试研究了阻燃体系的阻燃性能,通过热失重分析(TGA)研究了复配阻燃体系的热性能,采用扫描电镜(SEM)观察阻燃体系燃烧炭层的形貌。研究表明,AlPi与EA复配比例为7∶3时阻燃效果最好,材料氧指数达到34.6%,通过UL-94V-0级,热释放速率峰值(PHRR)降低至653kW/m2;热重分析表明,复配阻燃体系的加入促进了PBT的提前分解成炭,增加了阻燃PBT的残炭量;燃烧炭层扫描电镜说明,复配阻燃体系能形成连续致密的膨胀炭层,提高阻燃效果。     

一种含有硅磷杂化物的环氧树脂固化物的热性能与阻燃性能

利用γ-环氧丙氧基三甲氧基硅烷与磷酸合成了一种含磷硅烷偶联剂,将其与正硅酸乙酯和甲基三乙氧基硅烷反应得到一种硅磷杂化物(HSP)。将HSP加入到双酚A型环氧树脂,以4,4′-二氨基二苯基甲烷为固化剂制备了一种含有硅磷杂化物的环氧树脂固化物。对此固化物的玻璃化转变温度(Tg)、热降解性能和极限氧指数(LOI)进行了测试。结果显示,该固化物的热性能与阻燃性能得到明显改善。当HSP含量占环氧树脂用量的30%时,与纯环氧树脂固化物相比,Tg提高了5℃,700℃残炭率提高了68.4%,LOI达到27.2,获得了明显的阻燃和提高热稳定性等效果。     

纳米ZIF-8@短碳纤维的制备及其对环氧复合材料阻燃、抑烟和力学性能的影响

通过原位生长的方法制备了ZIF-8@短碳纤维(SCFs)材料,将其与聚磷酸铵(APP)一起加入环氧树脂(EP)制备了阻燃性能和力学性能均有所提高的环氧树脂复合材料.通过氧指数测定仪、水平垂直燃烧测定仪、锥形量热仪及万能电子拉力机对ZIF-8@SCFs-APP/EP复合材料进行了阻燃与力学性能的测试.实验结果表明,与添加...     

聚磷酸铵及季戊四醇膨胀型阻燃环氧树脂的阻燃性能

研究了聚磷酸铵(APP)和季戊四醇(PER)阻燃环氧树脂的阻燃性能和热分解特性。结果表明,阻燃环氧树脂的氧指数(LOI)随APP含量的增加而增加;当APP添加量达到20%时,阻燃环氧树脂的垂直燃烧性能达到V-0级。在APP阻燃环氧树脂中引入成炭剂PER使得体系的LOI值有所降低,但适量PER的引入使得阻燃体系的最大热释放速率降低。热失重(TG)实验结果表明,与未阻燃的环氧树脂相比,阻燃环氧树脂的初始分解温度有所降低,但在高温下阻燃环氧树脂的热稳定性较好。此外,还采用了激光拉曼光谱对阻燃环氧树脂燃烧后的炭层进行了分析。     

聚磷酸铵及季戊四醇膨胀型阻燃环氧树脂的阻燃性能EI北大核心

研究了聚磷酸铵(APP)和季戊四醇(PER)阻燃环氧树脂的阻燃性能和热分解特性。结果表明,阻燃环氧树脂的氧指数(LOI)随APP含量的增加而增加;当APP添加量达到20%时,阻燃环氧树脂的垂直燃烧性能达到V-0级。在APP阻燃环氧树脂中引入成炭剂PER使得体系的LOI值有所降低,但适量PER的引入使得阻燃体系的最大热释放速率降低。热失重(TG)实验结果表明,与未阻燃的环氧树脂相比,阻燃环氧树脂的初始分解温度有所降低,但在高温下阻燃环氧树脂的热稳定性较好。此外,还采用了激光拉曼光谱对阻燃环氧树脂燃烧后的炭层进行了分析。     

无卤复合型阻燃剂对环氧树脂阻燃性能的影响

以双酚A型环氧树脂E51为基料,自制的聚酰胺3369号为固化剂,加入由三聚氰胺甲醛树脂、聚磷酸铵、硅树脂配制成的复合型阻燃剂(MAPPSi)制备出无卤阻燃环氧树脂。通过氧指数仪、垂直燃烧仪(UL-94)、锥形量热仪和热重分析仪研究了材料的阻燃性能和热降解行为;通过扫描电子显微镜、万能拉力机研究了材料的表面形态和力学性能。结果表明,当阻燃剂MAPPSi质量分数达到18%后,极限氧指数从19.6%提高到32.5%,垂直燃烧效果通过UL-94 V-0级,拉伸强度为55.6 MPa,剪切强度为24.2 MPa。     

疏水阻燃微胶囊的制备及其在牛皮纸中的应用

目的为改善聚磷酸铵的阻燃性及热稳定性,降低其对纸材物理性能的影响,制备一种疏水阻燃微胶囊。方法以聚磷酸铵、季戊四醇、铜改性4A分子筛为芯材,以海藻酸钠和氯化钙为原料制备壁材,在外壳包覆SiO₂微粒,并制备阻燃牛皮纸。采用极限氧指数（LOI）测试、垂直燃烧测试（VBT）、烟密度测试（SDT）、微型量热仪（MCC）和热重分析（TG）表征阻燃纸的阻燃性和热稳定性,采用场发射扫描电镜（SEM）、透射电镜（TEM）表征疏水阻燃微胶囊的微观形貌,用傅里叶变换红外光谱（FTIR）表征试样的官能团特征,并根据国标测定纸张试样的抗张强度和撕裂度。结果涂布疏水阻燃微胶囊的牛皮纸试样的极限氧指数达到了36.3%,与空白组相比,烟释放总量、热释放速率峰值和热释放总量分别降低了42.44%、52.4%、36.1%,抗张强度和撕裂度分别提高了8.2%、177.1%,疏水阻燃微胶囊的表面形貌特征、元素分析结果以及红外光谱分析结果可表明,阻燃剂被成功包覆,并且SiO2微粒成功沉积在微胶囊壁材的表面。结论疏水阻燃微胶囊能有效改善阻燃剂的阻燃性、抑烟性和热稳定性,提高了基材的力学强度,降低了微胶囊的...     

凝固科学技术与材料

从凝固科学与实践发展的角度介绍了当前凝固材料体系的基本框架和凝固科学主要发展阶段的基本理论。作为材料科学与工程的基本组成，凝固科学技术正在现代科学理论的基础上针对传统材料的改性提高和新材料的发展需求，以控形、控构、控性为目标开展优质铸件的定向、晶体生长、快凝、深过冷及各种新型和超常领域凝固过程的研究，并介绍了其中某些方面和展望了可能的发展趋势。     

Development and challenges of planning and scheduling for petroleum and petrochemical production

Production planning and scheduling are becoming the core of production management, which support the decision of a petrochemical company. The optimization of production planning and scheduling is attempted by every refinery because it gains additional profit and stabilizes the daily production. The optimization problem considered in industry and academic research is of different levels of realism and complexity, thus increasing the gap. Operation research with mathematical programming is a conventional approach used to address the planning and scheduling problem. Additionally, modeling the processes, objectives, and constraints and developing the optimization algorithms are significant for industry and research. This paper introduces the perspective of production planning and scheduling from the development viewpoint.     

江澳两地高校文创设计的协同研究与商业实践

目的 探索江门世遗文化的传承、发展和转化的新思路,践行国家在《粤港澳大湾区发展规划》纲要中要求江门承担与港澳地区文化创意合作与开发任务的分工。方法 与澳门高校紧密合作,开展专业培训课程,以开平碉楼为例,从人文视角开展设计研究,梳理开平碉楼的文化脉络,把世遗文化的元素和其背后的文化融入文创产品中,提升文创产品的附加值,推动当地文创产业结构的变革。结果 两地高校构建了稳定的科研团队,开设长期有效的设计培训课程,与景区建立了研究协作关系,帮助景区构建了一套产销研的商业模式。结论 以跨区域高校合作为平台,以文创产品为抓手,依托江澳两地的资源优势,可以构建江门世遗文化全新的品牌形象,最终推动开平世遗文化的活化。     

Error and uncertainty in modeling and simulation

This article develops a general framework for identifying error and uncertainty in computational simulations that deal with the numerical solution of a set of partial differential equations (PDEs). A comprehensive, new view of the general phases of modeling and simulation is proposed, consisting of the following phases: conceptual modeling of the physical system, mathematical modeling of the conceptual model, discretization and algorithm selection for the mathematical model, computer programming of the discrete model, numerical solution of the computer program model, and representation of the numerical solution. Our view incorporates the modeling and simulation phases that are recognized in the systems engineering and operations research communities, but it adds phases that are specific to the numerical solution of PDEs. In each of these phases, general sources of uncertainty, both aleatory and epistemic, and error are identified. Our general framework is applicable to any numerical discretization procedure for solving ODEs or PDEs. To demonstrate this framework, we describe a system-level example: the flight of an unguided, rocket-boosted, aircraft-launched missile. This example is discussed in detail at each of the six phases of modeling and simulation. Two alternative models of the flight dynamics are considered, along with aleatory uncertainty of the initial mass of the missile and epistemic uncertainty in the thrust of the rocket motor. We also investigate the interaction of modeling uncertainties and numerical integration error in the solution of the ordinary differential equations for the flight dynamics.     

Density and viscosity of tetralin and trans-decalin

New measurements are reported for the density and viscosity of tetralin and trans-decalin. The density was determined from room temperature to 60°C for tetralin and to 95°C for trans-decalin. The kinematic viscosity was measured up to temperatures slightly above 100°C. Our results improve upon the values recommended by the American Petroleum Institute for these liquids.     

The Candela and Photometric and Radiometric Measurements

The national measurement system for photometric and radiometric quantities is presently based upon techniques that make these quantities traceable to a high-accuracy cryogenic radiometer. The redefinition of the candela in 1979 provided the opportunity for national measurement laboratories to base their photometric measurements on optical detector technology rather than on the emission from high-temperature blackbody optical sources. The ensuing technical developments of the past 20 years, including the significant improvements in cryogenic radiometer performance, have provided the opportunity to place the fundamental maintenance of photometric quantities upon absolute detector based technology as was allowed by the 1979 redefinition. Additionally, the development of improved photodetectors has had a significant impact on the methodology in most of the radiometric measurement areas. This paper will review the status of the NIST implementation of the technical changes mandated by the 1979 redefinition of the candela and its effect upon the maintenance and dissemination of optical radiation measurements.     

Creation and motion of dislocations and fracture in metal and silicon crystals

By making a step on one surface ( ) of a rectangular small paralellepiped copper crystal, dislocations could be created by the molecular dynamic method. The dislocation created was not a complete edge dislocation but a pair of Heidenreich-Shockley partial dislocations. Each time a dislocation was created, the stress on the surface was released. Small copper crystals having a notch were pulled (until fracture), compressed and buckled by use of the molecular dynamic method. An embedded atom potential was used to represent the interaction between atoms. Dislocations were created near the tip of the notch. A very sharp yield stress was observed. The results of high speed deformations of pure silicon small crystals using the molecular dynamics are presented. The results suggest that plastic deformation may be possible for the silicon with a high speed deformation even at room temperature. Another small size single crystal, the same size and the same surfaces, was compressed using molecular dynamic method. The surfaces are {110}, {112} and {111}. The compressed direction was [111]. It was found that silicon crystals are possible to be compressed with a high speed deformation. This may suggest that silicon may be plastically deformed with high speed deformation.     

SMC／BMC的回收与再利用

SMC／BMC废弃物对工业及环境造成了很大影响，指出了SMC／BMC回收再利用的紧迫性。通过对目前国际上SMC／BMC回收再利用的3种典型途径优缺点的对比，参照国外SMC／BMC回收再利用的先进方法，对我国SMC／BMC回收再利用提供了可行的建议．