聚甲基丙烯酸甲酯氧指数标准物质的研制

介绍聚甲基丙烯酸甲酯氧指数标准物质的研制过程：对标准物质的制备技术、均匀性检验、稳定性考察及定值和不确定度进行了逐项分析。采用本体聚合的聚甲基丙烯酸甲酯板材直接加工制备标准物质,标准物质具有良好的均匀性和稳定性,定值准确可靠,标准值为17．9％,扩展不确定度为0．28％。     

热辐射通量对沥青改性PMMA燃烧特性的影响

采用本体聚合法制备沥青改性聚甲基丙烯酸甲酯(PMMA)块体,研究了热辐射通量对其热释放速率平均值、质量损失速率平均值、点燃时间、CO及CO_2产率的影响。结果表明,添加沥青的PMMA点燃后300 s内平均热释放速率由569 kW/m~2降低到了525 kW/m~2,沥青使其燃烧更加平稳;沥青改性PMMA的平均热释放速率、质量损失速率和CO产率与热辐射通量成线性递增关系;点燃时间随着辐射通量的增加而呈指数衰减趋势;CO_2产率在热辐射通量低于40 kW/m~2时基本不变,高于40 kW/m~2时呈线性递增。添加沥青之后PMMA能够平稳燃烧使其可以作为锥形量热仪标准物质候选物,得到的燃烧特性与热辐射通量的函数关系式为其不确定度评估提供了依据。     

脱脂乳粉中硝酸盐、亚硝酸盐标准物质制备技术研究与评估

对脱脂乳粉中硝酸盐、亚硝酸盐标准物质样品制备技术进行了研究与评估。采用基体添加-真空冷冻干燥法制备标准物质候选物。选择乙酸沉淀蛋白-固相萃取/离子色谱紫外检测法对所制备样品进行评估。与国家标准中推荐的离子色谱电导检测器相比,采用紫外检测器可有效避免乳粉基质中存在的共洗脱组分对亚硝酸盐测定的干扰,且测量精密度得到改善,更有利于满足样品制备回收率、均匀性与稳定性评估的技术要求。经考察,样品中亚硝酸盐、硝酸盐目标制备值与测得值吻合,制备回收率分别为91%,101%;经方差分析,最小取样量1.0 g时,由样品中亚硝酸盐与硝酸盐均匀性引入的相对不确定度分别为2.9%和0.3%;-70,-20,4,20,35,45℃下同步、加速稳定性实验与线性回归趋势分析结果表明,样品短期稳定性及-20℃干燥、真空、避光保存条件下的长期稳定性预期良好。本研究确立了乳粉中亚硝酸盐与硝酸盐标准物质研究的可行性,所建立的制备技术可以确保标准物质定值结果的准确性。     

辛基二茂铁同分异构体纯度标准物质的定值技术研究

(2-辛基)-二茂铁、(3-辛基)-二茂铁和(4-辛基)-二茂铁是辛基二茂铁主要的3种同分异构体,由分离工业品辛基二茂铁制备而来。目前国内外金属有机化合物的标准物质有限,对这3种异构体进行高精度定值比较困难。该文首先考察标准物质候选物的均匀性和稳定性;再确定其中各杂质种类,用杂质扣除法对各候选物进行定值,重点研究了气相色谱法对各候选物中有机杂质及有机溶剂的定值技术,评定了标准物质的不确定度,为相关物质在高新技术领域的应用奠定了基础。     

大米成分分析标准物质的研制

从辽宁盘锦、四川简阳和湖南岳阳采集3个大米标准物质为候选物,粉碎至粒径小于0.18 mm的颗粒,并充分混匀.采用X-射线荧光光谱法进行均匀性检验,采用等离子体质谱法进行稳定性检验,结果显示制备的大米标准物质均匀性、稳定性良好.由14家实验室联合定值,采用高灵敏度、高精度的方法测试了58种元素,其中43种元素给出标准值.     

苯结晶点标准物质的制备

介绍苯结晶点标准物质的制备方法。以纯苯、正庚烷为原料,将不同体积比的苯与正庚烷混合得到苯结晶点标准物质候选物。采用F检验对标准物质均匀性进行检验,采用t检验对标准物质稳定性进行检验,采用多家实验室联合定值的方法对苯结晶点标准物质定值,并评定了不确定度。结果表明,所研制的标准物质量值准确可靠,均匀性、稳定性良好,标准值的扩展不确定度为0.04 ℃(k=2),能够用于苯结晶点测定仪计量校准,保证苯结晶点测量结果的准确可靠。     

铝合金化学成分标准物质的研制

介绍铝合金化学成分标准物质的研制过程。采用中频感应电炉熔炼法制备了铝合金化学成分标准物质候选物,并对标准物质候选物的均匀性和稳定性进行了考察。选择6家具有资质的实验室对研制的标准物质中各化学成分进行协作定值,并对各元素定值的不确定度进行评定。结果表明,在95%的置信区间内标准物质均匀性良好,经过13个月稳定性考察试验,标准物质稳定性良好。Si,Fe,Cu,Mn,Mg,Ti,Cd,V,Zr,B,Sn,Zn的定值结果分别为0.013 8%,0.012 5%,2.868%,0.185%,0.014 0%,0.082 8%,0.041 7%,0.032 9%,0.031 4%,0.003 8%,0.003 4%,0.025 6%,定值结果的相对扩展不确定度为1.4%~9.0%(k=2)。研制的标准物质达到相关技术要求,可用于该类铝合金材料的质量控制。     

银精矿成分分析系列标准物质研制

研制了系列银精矿标准物质。从日常检验样品中收集了15个不同含量的银精矿样品，每个样品收集5～8个批次，根据预留样品各元素成分含量综合考量后，筛选出4个不同品位的银精矿质控样品作为标准物质候选物，对标准物质候选物进行破碎、筛分、混匀及缩分，然后进行均匀性检验、稳定性进行检验，再由6家权威实验室进行协作定值，并对不确定度进行评定。结果表明，所研制的银精矿标准物质具有良好的均匀性和稳定性。该系列银精矿标准物质共定值6种元素，包括Pb(15%～56.99%)、Au(0.22～1.59 g/t)、Ag(2 913.6～4 855.0 g/t)、Cu(0.21%～1.16%)、As(0.12%～1.87%)、Zn(3.33%～10.58%)，制备过程及定值结果符合国家一级标准物质的规定。     

ITO成分分析标准物质的研制

研制3种掺杂铁、铜、铅、锌、钙、镁金属元素的氧化铟锡(ITO)成分分析标准物质。采用溶胶凝胶和共沉淀相结合的方法制备标准物质候选物,用电感耦合等离子体发射光谱法对其进行均匀性、稳定性检验及定值分析。采用8家具有资质的实验室对研制的标准物质进行协作定值,对定值结果的不确定度进行评定。结果表明:研制的ITO成分分析标准物质具有良好的均匀性和稳定性,3种标准物质中氧化锡含量在1%~10%之间,相对扩展不确定度为0.7%~6.6%(k=2);6种掺杂元素含量在0.05%~0.30%之间,相对扩展不确定度为3.4%~11%(k=2)。     

黑索今纯度标准物质的研究

通过重结晶法制备出均匀性合格的军用纯度标准物质黑索今（RDX）候选物,采用“杂质减除法”对标准物质进行定值,用电位滴定法对定值结果进行验证。RDX标准物质的纯度值为99．69％,其扩展不确定度为0．03％（k=2）。     

Correlation analysis of cone calorimetry test data assessment of the procedure with tests of different polymers

Correlation algorithms are used to analyse the relationship amongst heat release rate, carbon dioxide and carbon monoxide generated in cone calorimetry test of material flammability. These correlation algorithms include Pearson??s correlation, Spearman??s rank correlation and Kendall??s rank correlation. Cone test data of seven materials are analysed. These materials are two kinds of polyvinyl chloride wall panel, glass-reinforced plastics, vinyl panel, polymethyl methacrylate, polyurethane and two types of expanded polystyrene foam. Correlation coefficients are calculated for cone calorimeter results from tests at 50?kW?m^?2 of these materials. The distribution of the coefficients would be used to discriminate the test materials according to the so-called FO-categories which can help to predict the time to flashover.     

Synthesis of a novel phosphate‐containing highly transparent PMMA copolymer with enhanced thermal and flame retardant properties

A novel poly(methyl methacrylate) (PMMA)‐based copolymer (PMMA‐co‐BDPA) rich in aromatic rings was synthesized via radical copolymerization between a phosphorus‐containing acrylic monomer (BDPA) and methyl methacrylate (MMA). UV‐vis spectroscopy demonstrated that the copolymer had high transparency. Thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC) were used to test the thermal properties of the composites. Additionally, the PMMA‐co‐BDPA‐15 copolymer exhibited a 23% increase in the limited oxygen index (LOI) value. A cone calorimeter test indicated that the peak heat release rate (pk‐HRR) of PMMA‐co‐BDPA was reduced by 29.2% compared with that of pure PMMA, and the carbon yield of burning was obviously increased. The combined test results demonstrated that the prepared copolymer material had good transparency, thermal stability, and flame retardancy.     

4,9-脱水河豚毒素国家标准样品的研制

研制4,9-脱水河豚毒素国家标准样品。以河豚鱼卵巢为原料,提取制备4,9-脱水河豚毒素,采用红外光谱(IR)、高分辨质谱和核磁共振谱(NMR)进行结构确证。样品分装成140瓶后,采用柱后衍生–高效液相荧光法进行均匀性、稳定性检验和定值分析。从样品中随机抽取15瓶进行均匀性检验,经F检验表明在95%的置信区间范围内样品均匀性良好;稳定性考察按照40℃加速试验稳定性(6个月)进行,结果表明在考察期间内样品稳定性良好;标准样品经国内8家具有分析资质的实验室进行协同定值,并评定了定值结果的不确定度,4,9-脱水河豚毒素标准样品定值结果为97.77%,相对扩展不确定度为0.4%(k=1.96)。该标准样品达到国家标准样品的技术要求,可用于有关脱水河豚毒素的方法校正和质量控制。     

Combustion behavior and thermal stability of ethylene-vinyl acetate composites based on CaCO3-containing oil sludge and carbon black

CaCO₃-containing oil sludge (OS) is a by-product from petroleum industry, with great amount of production. Therefore, an effective processing methods for CaCO₃-containing OS is urgently needed. Herein, ethylene-vinyl acetate (EVA) composites based on CaCO₃-containing OS and carbon black (CB) were prepared by melt blending method. The combustion behavior and thermal stability of flame-retardant EVA/OS/CB composites were investigated by cone calorimeter test, limiting oxygen index (LOI), scanning electron microscopy (SEM), smoke density test (SDT), and thermogravimetry-Fourier infrared spectrometry. The heat release rate and smoke production rate of the ternary composites containing 3% CB significantly decreased compared with the EVA/OS composites and pure EVA. Moreover, addition of a certain amount of CB could evidently increase LOI values. The morphologies and structures of the residues, revealed by SEM, ascertained that a better carbonaceous protective layer was formed on the ternary composites than the EVA/OS composite. It was obtained from SDT that CB in the material could retard the smoke production with the application of the pilot flame. The EVA/OS/CB composites assumed a higher thermal stability than the EVA/OS composites and pure EVA.

     

一种高紫外-短波蓝光屏蔽的油溶性碳点的水热制备及其应用

以2-羟基-4-甲氧基二苯甲酮为碳源，乙二胺为氮源，通过水热法合成一种紫外和短波蓝光双重吸收的油溶性氮掺杂碳点（Carbon Dots,CDs）。将该CDs与聚甲基丙烯酸甲酯复合制得具有紫外光和短波蓝光屏蔽效果的复合镜片材料，当CDs的质量分数为1%时，复合镜片在紫外光区的平均透过率为0%、在短波蓝光区的平均透过率为1.6%，吸收效率为99.6%，是一种强防紫外-短波蓝光材料。     

Synergistic effect of carbon nanotubes and decabromodiphenyl oxide/Sb2O3 in improving the flame retardancy of polystyrene

Brominated flame retardant polystyrene composites were prepared by melt blending polystyrene, decabromodiphenyl oxide, antimony oxide, multi-wall carbon nanotubes and montmorillonite clay. Synergy between carbon nanotubes and clay and the brominated fire retardant was studied by thermogravimetric analysis, microscale combustion calorimetry and cone calorimetry. Nanotubes are more efficient than clay in improving the flame retardancy of the materials and promoting carbonization in the polystyrene matrix. Comparison of the results from the microscale combustion calorimeter and the cone calorimeter indicate that the rate of change of the peak heat release rate reduction in the microscale combustion calorimeter was slower than that in the cone. Both heat release capacity and reduction in the peak heat release rate in the microscale combustion calorimeter are important for screening the flame retardant materials; they show good correlations with the cone parameters, peak heat release rate and total heat released.     

20nm银粉末粒度标准物质的研制

研制了用于X射线小角散射仪校准的20 nm粉末粒度标准物质,并对标准物质的制备技术、均匀性检验、稳定性考察及定值不确定度进行了分析。研制的银粉末粒度标准物质具有良好的均匀性和稳定性,标准值为17.2 nm,相对扩展不确定度为6%。     

低温热分析标准物质的研制

研制了两种0~100℃热分析标准物质,分别为金属镓和水杨酸苯酯标准物质。研制的标准物质具有良好的均匀性和稳定性,采用与NIST,LGC相应标准物质比较的方法定值。NIST为SRM 2234镓,其定值采用288.6~314.35 K范围内的绝热热量计测得温度及热量值;LGC用绝热法为水杨酸苯酯的熔化温度和熔化热定值,两种方法都可以直接溯源至SI单位。对定值结果的不确定度进行了分析和评定。镓和水杨酸苯酯标准物质的熔化温度分别为(29.77±0.20)℃(k=2),(41.81±0.34)℃(k=2);熔化热分别为(80.52±0.48)J/g(k=2),(88.94±0.62)J/g(k=2)。研制的两种标准物质满足国家标准物质的技术要求,申报已获批准。