The deintercalation effect of FeCl3–graphite intercalation compound in paraffin liquid lubrication

The weld load of graphite and FeCl₃–graphite intercalation compound as an additive in paraffin liquid were evaluated with a Four-ball tester. The analytical tools, such as X-ray diffractometer, X-ray photoelectron spectrometer, and electron spin resonance spectrometer were used to investigate the reaction between steel and graphite intercalation compound. FeCl₃–GIC was found to exhibit over a twofold increase in weld load relative to graphite. Deintercalated FeCl₃ surrounding the contact favours the reaction of steel and graphite intercalation compound, which leads to an increase of weld load.     

Potential use of poly(lactic acid) nanofibers mats as Nano-sachets in postharvest of climacteric fruits and vegetables

This study is reported as the first demonstration of the use of solution blow spun mats in a Nano-sachet system containing a humidity absorber hydrogel and a paraffin wax tablet impregnated with potassium permanganate (KMnO₄) for exogenous ethylene (ex-C₂H₄) oxidation, in order to delay fruit ripening. The tomatoes quality during storage time was characterized by gas chromatography (GC) (ethylene concentration and CO₂ emission analysis—respiration rate), and colorimetry (green/red color parameter). Ex-C₂H₄ production over storage time was reduced for the Nano-sachet system when compared to the control system. Color changes, from 72 to 120 h, displayed fruit still predominantly green in the Nano-Sachet system (a* from −9.1 to −6.9), color transition green-red in the TNT-sachet (−7.5 to −0.3) and increased red color fruit in the control system (−6.1 to 3.7). This work suggests that nanofibrous mats can be used as a packaging system with the ability to protect, potentialize ethylene oxidation and extend climacteric fruits and vegetables quality in shelf life.     

EVA用于低熔点石蜡的定形支撑材料的研究

采用一定配比的固态与液态的混合熔融石蜡作为相变材料、EVA树脂作为支撑材料制备定形相变材料。研究了混合石蜡的热性能、选择不同型号EVA树脂时石蜡含量与材料相变焓之间的关系以及石蜡含量的临界值、定形相变材料的热稳定性和微观形貌。结果显示使用VA含量较低的EVA14/2树脂,可以提高石蜡包裹量并增加EVA树脂与石蜡之间的结合力,从而制成具有较高相变焓和具备良好热稳定性的定形相变材料。     

用于墙体建筑节能的复合相变材料的试验研究

以石蜡、膨润土为原料,制备了石蜡/膨润土复合相变材料。利用金相显微镜和差示扫描量热仪分别对其微观形貌和热性能进行了观察和表征。试验结果表明,当膨润土与石蜡的质量比为2:1,搅拌速度为3000r/min时,制备的复合相变材料体系均匀、稳定,具有良好的热物理性能。     

石蜡@碳酸钙相变微胶囊的自组装制备及其热物性

采用自组装法成功设计制备了石蜡 @CaCO₃ 相变微胶囊, 并研究了不同芯壁比对相变微胶囊性能的影响。 通过扫描电子显微镜发现所得的微胶囊呈明显的球状, 由 X 射线衍射曲线可以看出, 颗粒壳体的结晶型为方解石型 和球霰石型的一种混合性结晶型。其相变研究结果表明当芯壁比为 1 : 1 时, 微胶囊的包封率和相变潜热达到最大, 分别为 73.7% 和 102.8 J/g。此时制备得到的微胶囊的热导率相对于石蜡芯材可提高 414.8%。制备胶囊过程中, 不同 的芯壁比会影响微胶囊的结构形貌、包封率以及热学性能。综合测试结果表明: 当微胶囊的芯壁比为 1 : 1 时, 所得 微胶囊的性能最佳。     

棕榈酸/石蜡复合相变储能材料

将石蜡(PW)与棕榈酸(PA)熔融超声共混,制备出了一系列PA/PW复合材料。采用瞬态热丝法(SHW,Short-Hot-Wire)测量PA/PW复合材料的导热系数,用差示扫描量热仪(DSC,Differential Scanning Calorimetric)分析复合材料的相变温度(T)和相变潜热(L),采用红外光谱仪(FTIR,Fourier Transform Infrared)对复合物的组成进行表征。复合材料的红外吸收光谱图表明,PW和PA只是简单的物理混合,未生成新物质。复合相变材料的导热系数大致随温度的升高而降低,而在30和50℃左右时由于固-固和固-液相变的作用,导热系数测量值出现了一定程度的升高。复合材料的Ts-s(固-固相变温度)都比PW的略高;与纯PW相比,除PA的质量分数w=35%之外,其他比例复合材料的Ts-l(固-液相变温度)都较纯PW的低;除w=35%的Ls-l(固-液相变潜热)比纯PW的低之外,其他比例复合材料的Ls-l都比纯PW的Ls-l高。     

三个杜鹃花品种花芽分化的观察研究

以不同花期的丹东杜鹃花品种为材料,采用石蜡切片法,研究其花芽分化过程,为进一步研究杜鹃花的花期控制提供理论依据。结果表明:在丹东地区杜鹃花的花芽分化从6月中下旬开始至8月末结束,是在长日照、高温环境中进行的;杜鹃花的花芽分化可以分为四个时期:开始分化期、花萼分化期、花瓣分化期、雄蕊和雌蕊分化期;不同花期杜鹃花的花芽分化存在差异,其中早花品种先于中花品种,晚花品种最晚。     

纳米Sb2O3/云母阻燃微粉的制备及其阻燃机理

以三氯化锑和片状云母为原料,通过醇解、水解反应,表面活性剂处理,制备了纳米Sb2O3/云母阻燃微粉.用TEM表征了纳米Sb2O3/云母的形貌及其在云母表面的组装行为,利用XRD研究了不同煅烧温度对氧化锑形态的影响,利用燃烧法研究了纳米Sb2O3/云母复合微粒的阻燃性能,探讨了阻燃机理.结果表明,当云母的质量分数为5%,煅烧温度为400℃时,制备的纳米Sb2O3/云母纯度较高,阻燃性能优异;Sb2O3均匀地组装在云母上,在组装过程中不易团聚,Sb2O3的平均粒径约为5 nm.纳米Sb2O3/云母和氯化石蜡协同体系的阻燃机理包括自由基捕获机理和物理作用.在高温下纳米Sb2O3与氯化石蜡分解产生的氯化氢反应生成SbCl3,SbCl3在燃烧区内发生分解, 可捕获气相中维持聚合物燃烧链式反应的活泼自由基,使得链反应终止.物理作用包括隔热、隔氧、降低燃烧反应温度等.     

太阳能蓄热石蜡类相变材料循环稳定性

研究了石蜡54号~56号、56号~58号、58号~60号相变材料的热稳定性,其相变温度在50~60℃之间.利用差示扫描量热(DSC)技术测定了经过1次、100次、200次、300次反复热循环的相变材料的相变温度和相变潜热,实验结果表明:随着热循环次数的增加,相变材料的相变温度和相变潜热的变化很小. 更多还原     

Synthesis and performance of polyurethane coated urea as slow/controlled release fertilizer

Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 μm were formed on urea surface, the urea nitrogen slow-release time can reach 40-50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.