Q系列差示扫描量热仪DSC

隐形眼镜的水胶膜必须具备基本的机械强度，有种针刺试验可以表征其耐用特性。ＤＨＲ流变仪具有法向力的力量再平衡（ＦＲＴ）专利，再进一步结合真实定位（True Position）专利功能下，拥有优异的挤拉（Squeeze-Pull Off）测试能力。此外还有自定义夹具惯量校正功能以及万用固定器（Generic Container Holder）的配合下，可以由用户自己研发专用合宜的测试套件。

热分析技术在橡胶领域应用得越来越广泛，本文简要介绍了示差扫描量热仪DSC、热重分析仪TGA、动态力学分析仪DMA和热机械分析仪TMA的基本原理和在橡胶领域的应用实例。

Since the introduction of the first commercial (temperature servo) device for quantitatively measuring heat flow into (or out of) a sample as it undergoes a transition, there has been considerable confusion about what name should be used to describe this analytical measurement (1). A wide variety of labels has been applied including Quantitative Differential Thermal Analysis (QDTA) (1,2,3), Dynamic Differential Calorimetry (DDC), Dynamic Enthalpic Analysis (DEA) and, of course, Differential Scanning Calorimetry (DSC). DSC has been the most accepted name largely because instrument manufacturers have used the term. With the introduction of other commercial devices, which also measure differential heat flow but are not based on the temperature servo approach , the confusion has increased. This confusion has been aggravated by the instrument manufacturers themselves who have often claimed unspecified advantages for their particular instrument. The manufacturer of the original commercial device, understandably, has attempted to limit the DSC definition exclusively to his design. He continues to claim that his instrument is the only “true DSC”.?

The purpose of this paper is to assist DSC users with interpretation of unusual or unexpected transitions in DSC results. The transitions discussed in the paper are several of the ones that most frequently create problems for the new user, and which can also fool even an experienced thermal analyst. By applying some of the recommended procedures and solutions, most laboratories will be able to improve the overall quality and interpretation of DSC results.

Two common problems in the TG-DTG analysis of unknown elastomer vulcanizates and probable solutions are discussed. The first problem concerns the difficulty in quantitatively determining the oil and elastomer in the compound in cases where their volatilization temperature range overlaps. After a review of the published works which studied this problem, isothermal TG (with or without vacuum) along with the use of "High Resolution" TG equipment is recommended. The second problem concerns separate determination of carbon residue from the elastomers and added carbon black in the compound, which very often oxidizes together. Subtraction of the carbon residue formed by the elastomers, determined by previous analyses, from the total weight loss in oxygen, was suggested in the literature. However, the quantity of char depends on type of the elastomer, as well as its concentration, curative type and amount and rate of heating. The problem is not, therefore, fully resolved. Experiments under slow feed of lean oxygen gas and isothermal temperature were also suggested in the literature. Under this condition, oxidation of carbon black and char may occur at slightly different temperatures and overlapping is minimized. However, this could be achieved only for large and medium particle size blacks (soft blacks) which oxidize at higher temperatures and not for the smaller particle size blacks, (used mostly in tire treads). Further work under slow feed of lean oxygen with a superimposed isothermal program and/or vacuum is recommended. The capability of the recently announced "High Resolution Thermogravimetric Analyzer" should also be explored.?

Although it is often assumed that the pH of a buffer solution remains constant during a differential scanning calorimetry (DSC) experiment, the pK of a buffer can in fact change signifi cantly between 0 oC and 100 oC. Such pH changes can result in sample denaturation, aggregation and precipitation that, in the absence of knowledge about the temperature stability of the buffer, could erroneously be ascribed solely to temperature-induced unfolding of the biomolecule.

成品农药经过包装贩卖后，在启用前势必经过一段储放期。对此，CIPAC MT 46.3 Accelated Storage Stability Test 规范出快筛农药储存热安定性的标准试验流程，其中涵盖了DTA (DSC)与TGA两种常见的热分析应用

DSC是在定义的气氛下测量样品发生转变时的温度与热流随温度或时间变化的函数关系；MDSC是在传统DSC上的提高，它将总的热流分解成可逆热流(热容)和不可逆(动力学)组分。可逆的信号包括热容，例如玻璃化转变和熔化；不可逆热流信号包括动力学成分，如结晶、结晶的完整性和重结晶、以及固化和分解等。

因为药物晶体具有很好的储存稳定性，药物公司在新药物配方中倾向采用结晶化合物。然而经常碰到的问题是药物存在多种结晶形式，即通常所说得多晶型。由于多晶型的每种晶型的物理性质、比如分散速率和生物活性有很大的不同，因此控制结晶的形势和含量显得十分重要。

DSC是在定义的气氛下测量样品发生转变时的温度与热流随温度或时间变化的函数关系；MDSC是在传统DSC上的提高，它将总的热流分解成可逆热流(热容)和不可逆(动力学)组分。

为得到精确的测试结果，需定期对DSC进行校准。另外，当如下条件改变时，也需重新校准仪器：吹扫气体，冷却附件，或更换了新炉子。根据仪器型号和所选热流，校准主要有以下几个方面：

在DSC测试中，待测样品及参比（如需要）会放置在样品盘中，再将样品盘放到DSC炉内的测试平台上，热通过样品盘由测试平台传递到样品，所以保证优异的热传导性是得到好的测试结果的前提。TA仪器提供了多种样品盘，可以满足不同材料的测试需求，并具有非常好的热传导性。

本文阐述了如何用DSC分析方法应用于药物学开发 因为晶型结构的药物一般具有较好的储存稳定性，制药公司一般偏好采用结晶的化合物作为新药的配方组成成分。然而通常遇到的问题是药物容易形成多种结晶结构的多晶型。因为多晶型在物理性质上存在很大的差异，例如由溶解速率的不同而导致的生物活性上的不同，因此控制药物的浓度和晶型形式就显得尤为重要。