1.1 本试验方法描述了使用最小量的材料确定试样中是否存在焓变，近似这些焓变发生的温度，并使用差示扫描量热法或压差扫描量热测定其焓（热）。 注1: 如果试图使用压差扫描量热法来了解液体或固体的热稳定性（如果它在测试过程中融化或产生气体或液体产物），则应注意，因为顶部空间体积与样品尺寸之比相对较大，因此蒸发效应可能会显着扭曲结果。通常，压差扫描量热计将限于需要加压反应性顶部空间的情况（即，液体或固体样品与气体的反应性 附录X1 ). 仍然建议使用密封的高压样品容器来评估液体或固体样品的固有热稳定性，即使在压力范围内 DSC 仪器 1.2 该试验方法可在固体、液体或浆料上进行。 1.3 该试验方法可在密封的高压样品容器中进行，该容器具有惰性或反应性顶部空间气氛，绝对压力范围为100 Pa至30 MPa，温度范围为273 K至800 K（0°C至527°C）。 1.4 以国际单位制表示的数值应视为标准。本标准不包括其他计量单位。 1.4.1 例外情况-- 提供英寸磅单位是出于对用户的礼貌 X1.3.3 , X1.4.1 和 X1.4.2 . 1.5 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 具体的安全预防措施见第节 8. . 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 该测试方法可用于检测潜在的危险反应，包括挥发性化学品的反应，并可用于估计这些反应发生的温度及其焓（热）。建议将该试验方法作为早期试验（或筛选试验），用于检测对热稳定性知之甚少的化学物质或混合物的热危害（见第节 8. ). 5.2 焓的变化幅度可能不一定表示特定应用中的相对危险。 例如，某些放热反应通常伴随着气体的析出，这增加了潜在的危险。或者，某些放热反应的能量释放程度可能与挥发性产物的限制程度大不相同。因此，放热的存在及其近似温度是本试验方法中最重要的标准（见第节 3. 和 图1 ). 5.3 如果样品质量损失（前后的质量差 DSC 分析除以之前的测试样品质量 DSC 分析）大于10%，则可能已经发生泄漏并且数据被泄露。样品泄漏通常会导致人为吸热或取消放热活动，这可能导致不安全的热稳定性评估。 5. 因此，强烈建议丢弃此类数据并重复分析。 5.4 当固体物质在 DSC 在研究分析或液体时，执行 DSC 密封高压内的分析 DSC 样品容器（能够容纳至少7MPa或最高温度下蒸汽压力的两倍）。这种密封的高压容器可以使蒸发的吸热效应最小化。例如，在0°C至400°C的温度范围内，在针孔铝锅和密封铝锅中研究了甲苯样品中20重量%的DTBP。两种分析都有超过99%的样品质量损失( 图3 )由于在沸点附近的蒸发（DTBP的沸点为111℃，甲苯的沸点为110.6℃），显示出单一的吸热峰，而密封的铝锅( 图4 )显示断裂活动。它们都没有提供放热信息，如中所示 图1 . 5. 图3 DSC 针孔铝盘内的曲线； 测试样品:甲苯中20%重量的DTBP 图4 DSC 密封铝盘中的曲线；测试样品:甲苯中20%重量的DTBP 5.5 密封高压中的顶部空间气体 DSC 样品容器可能影响热稳定性评估。与惰性顶部空间气体相比，反应性顶部空间气体可以引入放热峰（例如，当使用空气时的氧化峰），特别是对于有机样品。 5. 例如，乙二醇已经在镀金的 DSC 具有空气顶部空间（密封在实验室工作台上）和氮气顶部空间（在N2手套箱中密封）的样品容器。如中所示 图5 ，只有 DSC 用空气进行的测试显示出一个额外的放热峰值。 注2: 如果可以估计可用氧气，则可以近似空气氧化峰值的放热焓。基于氧气的氧化反应是放热的，释放约-100千卡/摩尔的氧气。 6. 假设样品在正常温度和压力（20°C和1个大气压）下密封，这相当于3。 65mJ/µL空气。例如，在中的测试中 图5 ，大约50µL的空气被密封在容器中，预计能量释放为–183 mJ或–56 J g 1. . 图5 DSC 乙二醇镀金曲线 DSC 具有不同顶部空间气体的样品容器（高压）；黑色:空气顶部空间；绿色:氮气顶部空间 5.6 对于某些物质，当测试具有低浓度物质的混合物时，放热反应期间的焓变化率可能很小，这使得难以评估不稳定性的温度。通常，在较高浓度下重复分析将通过增加焓的变化率来改进评估。 5.7 该试验方法的三个重要标准是:焓变化的检测；事件发生的近似温度及其焓的估计。

1.1 This test method describes the ascertainment of the presence of enthalpic changes in a test specimen, using minimum quantities of material, approximates the temperature at which these enthalpic changes occur and determines their enthalpies (heats) using differential scanning calorimetry or pressure differential scanning calorimetry. Note 1: Caution should be used if trying to use pressure differential scanning calorimetry to understand the thermal stability of a liquid or a solid (if it melts during the test or produces gas or liquid products), because the headspace volume to sample size is relatively large, so that the vaporization effect could significantly skew the results. Typically, the pressure differential scanning calorimeter would be limited to situations where a pressurized reactive headspace is required (that is, reactivity of a liquid or solid sample with a gas, more detail in Appendix X1 ). Sealed high-pressure sample containers are still recommended for the evaluation of intrinsic thermal stability of liquid or solid samples, even within a pressure DSC instrument. 1.2 This test method may be performed on solids, liquids, or slurries. 1.3 This test method may be performed in a sealed high-pressure sample container with an inert or a reactive headspace atmosphere with an absolute pressure range from 100 Pa through 30 MPa and over a temperature range from 273 K to 800 K (0 °C to 527 °C). 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4.1 Exceptions— Inch-pound units are provided as a courtesy to the user in X1.3.3 , X1.4.1 , and X1.4.2 . 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific safety precautions are given in Section 8 . 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This test method is useful in detecting potentially hazardous reactions including those from volatile chemicals and in estimating the temperatures at which these reactions occur and their enthalpies (heats). This test method is recommended as an early test (or a screening test) for detecting the thermal hazards of a chemical substance or a mixture where the thermal stability is poorly understood (see Section 8 ). 5.2 The magnitude of the change of enthalpy may not necessarily denote the relative hazard in a particular application. For example, certain exothermic reactions are often accompanied by gas evolution that increases the potential hazard. Alternatively, the extent of energy release for certain exothermic reactions may differ widely with the extent of confinement of volatile products. Thus, the presence of an exotherm and its approximate temperature are the most significant criteria in this test method (see Section 3 and Fig. 1 ). 5.3 If sample mass loss (the mass difference before and after DSC analysis divided by the tested sample mass before DSC analysis) is greater than 10 %, a leak likely has happened and the data is compromised. Sample leaking typically causes an artificial endotherm or cancels exothermic activities which could lead to an unsafe thermal stability evaluation. 5 Therefore, it is highly recommended to discard such data and repeat the analysis. 5.4 When solid substances which will melt in the temperature range of a DSC analysis or liquids are being studied, it is important to perform the DSC analysis within a sealed high-pressure DSC sample container (able to hold at least 7 MPa or two times the vapor pressure at the highest temperature). Such sealed high-pressure containers could minimize the endothermic effect of vaporization. For example, 20 % by weight DTBP in toluene sample has been studied within a pinhole aluminum pan and a sealed aluminum pan in a temperature range from 0 °C to 400 °C. Both analyses had a sample mass loss of over 99 %. The pinhole aluminum pan one ( Fig. 3 ) demonstrates a single endotherm peak due to the vaporization around the boiling point (boiling point: 111 ℃ for DTBP, 110.6 ℃ for toluene), while the sealed aluminum pan one ( Fig. 4 ) shows rupture activities. Neither of them provides the exotherm information, as seen in Fig. 1 . 5 FIG. 3 DSC Curve Within a Pinhole Aluminum Pan; Tested Sample: 20 % by Weight DTBP in Toluene FIG. 4 DSC Curve Within a Sealed Aluminum Pan; Tested Sample: 20 % by Weight DTBP in Toluene 5.5 The headspace gas in the sealed high-pressure DSC sample container may impact thermal stability evaluation. A reactive headspace gas may introduce an exothermic peak (for example, oxidation peak when using air) compared to an inert headspace gas, especially for organic samples. 5 For example, Ethylene Glycol has been studied within a gold-plated DSC sample container with an air headspace (sealed on a lab bench) and a nitrogen headspace (sealed in an N2 glove box). As seen in Fig. 5 , only the DSC test with air one shows an extra exotherm peak. Note 2: The exotherm enthalpy of the air oxidation peak may be approximated if the available oxygen can be estimated. Oxygen based oxidation reactions are exothermic and release about –100 kcal/mole of oxygen. 6 Assuming the sample is sealed at normal temperature and pressure (20 °C and 1 atm), this corresponds to 3.65mJ/µL of air. For example, in the test in Fig. 5 , about 50 µL air was sealed in the container, and the energy release is expected to be –183 mJ or –56 J g -1 . FIG. 5 DSC Curve of Ethylene Glycol in Gold-Plated DSC Sample Container (High-Pressure) with Different Headspace Gases; Black: Air Headspace; Green: Nitrogen Headspace 5.6 For some substances, the rate of enthalpy change during an exothermic reaction may be small when testing a mixture with a low concentration of the substance, making an assessment of the temperature of instability difficult. Generally, a repeated analysis at a higher concentration will improve the assessment by increasing the rate of change of enthalpy. 5.7 The three significant criteria of this test method are: the detection of a change of enthalpy; the approximate temperature at which the event occurs and the estimation of its enthalpy.