玻璃化转变温度 (Tg) 是定义材料完整性、制造条件和操作指南的基本材料特性，适用于聚合物、电子产品和先进材料等应用领域。玻璃化转变可以通过三种热分析技术进行测量：DSC、TMA 和 DMA 各有其适用的材料和应用。这篇博客将解释这些技术如何测量Tg，以及何时应该选择哪种技术。

玻璃化转变是指非晶态材料在加热时从玻璃态转变为橡胶态，或在冷却时从橡胶态转变为非晶态的温度区域。玻璃化转变实际上发生在一定的温度范围内，但通常被报道为一个单一的温度，称为 Tg。

了解玻璃化转变温度有助于解答一些重要问题，例如：

• 印刷电路板（PCB）在什么温度下有分层风险？
• 注塑成型或聚合物共混而不发生降解的理想温度是多少？
• 材料在使用过程中会发生变形或开裂吗？

玻璃化转变可以通过DSC、TMA和DMA来测量。这些热学技术均基于玻璃化转变过程中不同材料特性的变化来检测 Tg。选择正确的方法对于获得可靠的数据和对材料进行定量比较至关重要。

差示扫描量热法（DSC）是测量玻璃化转变最常用的方法。DSC 测量样品相对于惰性参考物的热量流入和流出，揭示热容变化，用于定义玻璃化转变。这些热容变化产生了三个温度值：玻璃化转变的起始温度、转变的中点温度和转变的结束温度。

实验设计对DSC结果至关重要。更高的加热速率可以提供更高的灵敏度，但由于仪器效应、样品热导率和转变动力学，会使 Tg 发生偏移。尽管如此，现代 DSC 仪器仍具有优异的基准性能，并且当与高加热速率相结合时，可为非晶态、半结晶态和增塑材料以及热固性树脂提供可靠的 Tg 测量。DSC 可以同时测量熔融、结晶和固化反应，提供其他方法所缺乏的额外热数据。

调制差示扫描量热法 (MDSC) 通过施加振荡热流，提供有关可逆和非可逆转变的更多信息。虽然体积弛豫吸热峰可能会扭曲传统 DSC 的 Tg，但 MDSC 将体积弛豫吸热峰与 Tg 处的热容变化逆向变化分离，从而获得更可靠的测量结果。MDSC 还可以区分不可逆转变（如冷结晶和固化），并提供检测与加热速率相关的转变的灵敏度。MDSC 对半结晶聚合物、多层薄膜或部分固化的热固性材料尤其有价值。

热机械分析 (TMA)是根据样品受热时尺寸的变化来测量玻璃化转变的。Tg 可以通过热膨胀的变化来测量，也可以通过探针穿透深度的增加来测量，因为材料在玻璃化转变过程中会软化。膨胀模式适用于刚性热塑性塑料和具有明确膨胀过渡的材料，而渗透模式更适用于在 Tg 以上明显软化的材料，例如较软的聚合物、涂料、粘合剂和一些弹性体。

对于填充、高度结晶或交联的材料，TMA 比 DSC 更合适，因为在 Tg 处观察到的尺寸变化通常很显著。然而，TMA 测得的 Tg 曲线通常较宽，可能受到探针加载条件的影响，并且可能受到体积弛豫效应的影响。

动态力学分析 (DMA)通过施加振荡的机械应力或应变来测量机械刚度和能量吸收的变化。随着分子运动在玻璃化转变过程中增加，储能模量（E’）急剧下降，使得DMA成为测定Tg最灵敏的技术之一。这种灵敏度非常适合检测高填充、结晶或交联材料中非晶态含量极低的Tg。

可以使用三个 DMA 事件来定义玻璃化转变的范围。储能模量起始点 (E’) 标志着玻璃化转变的开始，损耗模量峰值 (E”) 是玻璃化转变的中点，损耗角正切峰值代表转变的上限。

DSC、TMA 和 DMA 在测定不同材料的 Tg 时各有其优势和劣势。下表总结了根据我们的研究，不同热分析技术在评估不同材料的玻璃化转变温度（Tg）方面的相对效用：

有关更多信息和分析，请阅读完整的应用说明《探索热分析技术对玻璃化转变的敏感性》 。我们的免费热分析选型指南中提供了更详细的分析，介绍了哪些热分析仪器适合特定的应用。

如今的电池创新正不断突破极限，实现更高的能量密度、更高的功率以及更长的续航时间。然而，这些进步可能会带来严重的安全风险。在开放周期的早期阶段测量电池的安全性和稳定性，对于确保新设计在推进完整电池规模化量产前取得成功至关重要。

热稳定性是指材料在受热时抵抗降解的能力。对电池研发人员来说，幸运的是，材料科学领域已有一项成熟的技术可用于测量热流：差示扫描量热法 (DSC)。自 20 世纪 70 年代以来，Waters 材料科学事业部生产的 DSC 就广泛应用于聚合物、制药及其他材料科学研究领域。

电池研究人员和开发人员使用 DSC 来研究电池材料的热稳定性和分解行为，但传统的 DSC 并非专为电池测试而设计。当前的工作流程包括拆解电池单体，然后在 DSC 上对单个材料进行测试，但单独测试材料可能无法全面反映其热稳定性或交叉反应的情况。完整电池的安全测试往往被推迟到开发后期进行，这通常会导致高昂且耗时的整改成本。

Waters TA Instruments 纽扣电池差示扫描量热仪使电池研究人员和开发人员能够直接评估纽扣电池的安全性和性能，而无需拆解。如今，在开发的早期阶段便能实现完整电池的测试。这些测试可以通过识别可能引发自热或热失控的反应，为电池研发提供指导。然后，开发人员可以将这些数据与后期安全测试结果相结合，从而全面了解电池的稳定性。

航空航天业正日益向轻量化方向发展，即在不牺牲机械强度、耐久性或性能的前提下，采用密度更低的材料。轻量化具有诸多优势，包括加快生产速度、提高能效以及改善可回收性。该方法的核心在于优化材料的强度重量比，使组件能够在保持或超越所需力学性能的同时，将总质量降至最低。

向轻量化方向的转变，与航空航天业向大规模、高产率生产转型的总体趋势相契合；这种转型要求能够更快速且具备可重复性地制造飞机、卫星及先进空中交通平台。在美国，NASA 致力于实现高效率制造，以提升美国的市场领导地位和成本效益^。1

轻量化得益于复合材料技术的进步，而复合材料现已成为航空航天领域的主导材料。预计未来六年，航空航天热塑性复合材料市场将以 16.8% 的复合年增长率增长，^这为能够满足该不断扩张市场独特需求的制造商提供了绝佳机遇。然而，生产用于航空航天领域的新一代轻质复合材料并非没有独特的挑战。本篇博文将探讨顶尖研究人员如何优化适用于航空航天领域的轻质高效复合材料，同时确保强度与性能不受影响。

夹层结构是一种多层高性能复合材料，由两层薄面板和一个轻质蜂窝状芯材组成。^这些材料具有高强度重量比和高刚度，使其成为航空航天应用的理想选择。有两种热分析技术适用于优化夹层结构，特别是在航空航天领域。热重分析（TGA）用于测定热稳定性和降解特性，帮助工程师选择在高温下不会丧失强度或发生失效的材料。差示扫描量热法（DSC）通过分析熔融、结晶和玻璃化转变行为，有助于确定理想的加工条件，并筛选出具有最佳相变特性的共混物。

研究人员利用 Waters TA Instruments 评估了不同的材料混合配方，开发出了新型 4D 打印生物基形状记忆夹层结构。^他们利用 Waters TGA 评估了新材料的热稳定性，证实了不同混合配方表现出几乎相同的热降解特性。他们利用符合 ASTM D3418 标准的 Waters DSC研究了熔融与结晶行为；结果显示，某些添加剂导致了玻璃化转变温度（Tg）的降低，且其中一种共混物表现出更显著的熔融吸热峰。这项分析对于确定不同混合物之间的差异以及选择最适合特定最终用途的混合物至关重要。

动态力学分析（DMA）为实现材料强度重量比的最大化提供了支持；该技术通过测量材料随时间、温度和频率变化的力学性能来进行分析。DMA（动态热机械分析）通过以下方式支持轻量化：量化储能模量以筛选高刚度、低质量的配方；表征阻尼特性（tan δ）以平衡结构刚度与振动耗散；以及监测热转变过程，确保材料在工作温度范围内保持足够的刚度。

高温推进系统依赖于BMI（双马来酰亚胺）等热固性材料，以利用其玻璃化转变温度（Tg）和热稳定性。NASA研究人员利用Waters DMA，在涵盖从低温到高温的典型火箭燃烧室工况下，对燃烧室用树脂进行了研究。测试结果证实，随着后固化温度的升高，玻璃化转变温度（Tg）^随之提高；但在低于Tg起始温度的所有温度范围内，模量均有轻微下降。

新型制造技术正在推动轻量化创新：感应焊接和超声波焊接能够高效实现大规模、高精度且品质一致的轻量化制造。DMA 通过评估储能模量和损耗模量随温度的变化情况，为焊接设计提供支持。研究人员利用^Waters DMA评估了预热对碳纤维/PEEK复合材料层合板超声波焊接的影响。数据表明，该材料的能量耗散能力随温度变化，这是焊接过程中生热的主要驱动因素。利用DMA（动态热机械分析），他们确定了损耗模量峰值——即材料将超声波振动转化为内部热能效率最高的点——并据此调整了预热工艺，以充分利用这一特性。

增材制造是另一种日益普及的轻量化材料生产方法，具有更高的自动化程度、复杂性、材料利用效率及设计灵活性。在近期的一项研究中，研究人员探讨了两种用于制造航空次承力结构碳纤维增强复合材料（ ^CFRP ）的增材制造方法。他们利用 Waters 动态热机械分析仪（DMA）研究了该材料的粘弹性行为与热转变特性，并使用热机械分析仪（TMA）测量了随时间、温度和力变化而产生的尺寸变化。他们发现，打印参数对尺寸稳定性有显著影响。

最后，热分析对于预测新型轻质材料的最终使用性能及安全性至关重要。例如，在开发用于飞机机身和机翼的复合材料T型接头时，研究人员利用DMA（动态热机械分析）、流变学和DSC（差示扫描量热法）研究了该接头在服役条件下的响应特性，以确保其在飞行过程中保持稳定。8^同样，Waters公司科学家发布的一份应用说明也展示了TGA（热重分析）在预测最终用途性能方面的重要性，因为它能够测定分解温度，并根据温度和时间估算聚合物的使用寿命^。9在这些研究中，热分析技术为那些专为严苛使用环境设计的新型轻质材料提供了最终用途性能预测支持，从而在降低风险的同时加速了创新进程。

上述研究表明，热力学分析对于验证轻质材料在严苛航空航天工况下的强度、使用寿命及稳定性至关重要。随着制造商不断追求更高的生产效率和更大幅度的减重，DSC、TGA、DMA 和流变学等技术提供了必要的数据，助力设计出不仅更轻，而且在整个使用寿命期间更安全、更可靠的材料。从优化加工条件到分析热降解，材料表征是实现轻量化安全与高效的基石。

1. Taminger, K. NASA 高速率航空结构技术计划；美国国家航空航天局，2020年。https://ntrs.nasa.gov/api/citations/20200004300/downloads/20200004300.pdf .
2. 拉贾特·佐佩。2032年航空航天热塑性复合材料市场规模与份额Persistence Market Research。https ://www.persistencemarketresearch.com/market-research/aerospace-thermoplastic-composites-market.asp （访问于 2026年5月18日）。
3. 嗯。Ilham Akbar; Bidayatul Armynah; Tahir, D. 夹层复合结构 (SCS)：以聚合物和金属为填料的木质电磁干扰（EMI）屏蔽材料研究综述Industrial Crops and Products 2024, 215, 118619–118619. https://doi.org/10.1016/j.indcrop.2024.118619 .
4. Ghalayaniesfahani, A.; Oostenbrink, B.; Kasteren, H. van; Gibson, I.; Mehrshad Mehrpouya.生物基形状记忆夹层结构的4D打印Polymer 2024, 307, 127252–127252. https://doi.org/10.1016/j.polymer.2024.127252 .
5. Stelter, C.; Park, C.; Chu, S.-H.; Hudson, T. 经历从低温到高温循环的复合材料缠绕燃烧室用后固化双马来酰亚胺树脂的动态力学分析。Nasa.gov. https://ntrs.nasa.gov/citations/20240012459 （访问于 2026-05-18）。
6. Takeda, S.; Kugi, D.; Hoshi, H.; Mohammad Fikry, MJ; Ogihara, S. 预热对CF/PEEK复合材料层合板超声波焊接的影响。Composite Structures 2025, 373, 119668. https://doi.org/10.1016/j.compstruct.2025.119668 .
7. Maier, R.; Istrate, AM; Despa, A.; Mandoc, AC; Bucaciuc, S.; Stoica, R. 增材制造技术制备的聚合物复合材料热力学响应研究。Materials 2022, 15 (14), 5069. https://doi.org/10.3390/ma15145069 .
8. 张涛, 罗震, 邓京, 裴雨, 程鑫. 基于预浸料-RTM共固化工艺的高弯曲性能复合材料螺栓连接T型接头制备新方法.Polymers 2024, 16 (9), 1259. https://doi.org/10.3390/polym16091259 .
9. Browne, J. 聚醚醚酮（PEEK）的热分析 – Waters TA Instruments。https ://www.tainstruments.com/applications-notes/thermal-analysis-of-polyether-ether-ketone-peek-ta496/ 。

When it comes to selecting materials for your next innovative product, the material specification sheet is likely the first place that you will turn. This document provides core properties measured by the manufacturer and serves as an essential tool for supplier verification and new product development. However, while these sheets are reliable and provide a standard method for comparison, they often fail to tell the whole story.

For successful material selection, product performance, failure prevention, it is important to go beyond the spec sheet and conduct in-house testing. This proactive approach will save you both time and money by facilitating informed material choices and enhancing product design.

A material specification sheet provides a snapshot of a material’s key properties as measured by the manufacturer. These properties are typically measured using standardized methods such as ASTM or ISO standards, offering some consistency and comparability across different materials. The spec sheet can be used for various purposes:

• Supplier Verification: Ensuring that the material provided by a supplier meets the necessary criteria for production.
• New Product Development: Aiding in the selection of new materials during the design phase of a product.

While spec sheets provide a foundational understanding, relying solely on them can be risky; they often provide incomplete information to know the material’s performance or predict lifetime of a product, especially in real-world application conditions.

Spec sheets are foundational for understanding general material properties, but they often lack detailed information about how a material will behave under specific conditions, such as the effects of different temperatures, prolonged stress or stress cycles, or exposure to harsh environments. Uncovering these blind spots is necessary for improving processing conditions, understanding material lifespan, and ultimately selecting the right material at the start of your development process.

To fully understand a material’s properties and ensure it meets your specific requirements, additional testing is required. Here are some critical aspects to consider:

Environmental Impacts

Materials can perform differently under various environmental conditions, such as UV exposure, or humidity. Due to the impracticality of inspecting materials in active use, such as polymer coatings on wires embedded in walls, a quick test lasting only a few minutes to hours is conducted to estimate the long-term stability of these materials over decades.¹

Differential scanning calorimetry (DSC) with oxidative induction time (OIT) analysis helps predict the aging and degradation of polymers, guiding material selection for longevity and reliability. For instance, polymers exposed to heat, oxygen, or light degrade faster, and OIT provides insights into their lifespan.

A variation of the OIT test, known as high-pressure OIT (HPOIT), is becoming increasingly popular. Proponents argue that oxidative data obtained under high pressure and temperature conditions align more closely with results from traditional, accelerated aging tests. The HPOIT test offers two primary advantages: high pressure raises the boiling points of additives, reducing their volatility, and it increases the concentration of the reacting oxidizing gas. This enables the use of lower test temperatures or significantly reduces test durations at comparable temperatures.²

Alternatively, high-pressure thermogravimetric analysis (HP-TGA) simulates extended exposure to harsh environments by using a combination of heat and elevated pressure. It is particularly useful for materials used in industrial applications, such as cabling for electrical or fiber optic systems. Safeguarding polymers against catastrophic degradation when exposed to direct sunlight or buried underground is crucial for these applications.³

Mechanical Behavior

Understanding the mechanical properties of materials beyond the scope of the datasheet is essential for nearly every application. For example, the following should be considered:

• Temperature Effects: Materials can exhibit drastically different properties at varying temperatures. Datasheets typically only list tensile properties at room temperature, but materials are frequently expected to perform under higher or lower temperatures.
• Long-Term Loading: What happens if a material is subjected to a load for weeks, months, or even years? Will it deform over time, i.e., creep? Will it crack under prolonged stress, i.e., creep rupture? For example, a clothing hanger may perform well under normal use, but storing a heavy coat over winter could cause the neck to elongate and eventually break. In this example, the clothing hanger began failing to perform its function (holding up clothes) due to creep and fell off the rod. Had it not fallen due to deformation, it would have eventually cracked due to creep rupture.

• Repeated Loading: In a process known as fatigue, repeated loading can cause accumulating damage, leading to fracture. It is important to know the stress levels and number of loading cycles a material can withstand before failure. Polymers exhibit fatigue in a very different way than metals and fatigue life estimates cannot be extrapolated from tensile strength as easily. Additionally, the usage temperature can have a significant impact on fatigue life at much lower temperatures than metals.

Mechanical test instruments evaluate durability and mechanical characteristics under various stresses (forces), frequencies, and environmental conditions. Specifically, Electroforce load frame instruments measure a sample’s response to force, whether it is a single push or pull (tensile test), repetitive load (fatigue), or creep/stress-relaxation test. Mechanical testing also accounts for environmental effects by testing in temperature-controlled air, gas, or fluid submersion.

Material testing is crucial in manufacturing and product development because it minimizes the risk of product failure, which can have costly and even dangerous consequences. Unexpected material behavior can lead to malfunctions, product recalls, and reputational damage.

For example, a woven fiberglass composite had a manufacturer’s recommended operating temperature up to 130°C. However, Dynamic Mechanical Analysis (DMA) testing revealed that the material’s storage modulus and loss modulus began to change around 100°C.⁴ Further fatigue testing data revealed that the material had a 90% reduction in its fatigue life at 100°C.⁵ Manufacturers could have mistakenly put this material into products used at high temperatures, such as baking, without realizing that it was highly likely to break.

Conducting thorough testing upfront provides higher confidence in material choices, ultimately saving time, money, and resources. Moreover, comprehensive material testing contributes to better long-term product reliability and performance. By thoroughly examining how a material responds to factors like fatigue, creep, and environmental degradation, manufacturers can design products that not only meet initial requirements but also maintain integrity throughout their life cycle. This proactive approach fosters innovation in product design, as engineers gain a deeper understanding of the material’s limits and capabilities, allowing for the creation of more efficient, safer, and longer-lasting products.

Going beyond the spec sheet is not just a recommendation; it is a necessity. By investing in additional testing, such as OIT using DSC and HP-TGA, you can uncover profound insights about material performance. By adding DMA and Electroforce fatigue testing to your testing suite, you can better predict material properties at various temperature conditions and repeat loading. These insights will ensure you make informed decisions that save time, money, and valuable resources by selecting the proper material for your application conditions. TA Instruments is here to support you with precision instruments and technical expertise, ensuring you have the tools needed to expertly evaluate materials and make the best decisions for your projects.

The composites market is evolving fast. Global market projections indicate a 10.8 % growth by 2028, driven by the demand for composites across industries looking for materials with superior performance at reduced weight and cost.¹ This blog explores how advanced material analysis can enhance R&D and manufacturing processes in the composites market, ultimately leading to financial savings and increased efficiency.

While traditionally associated with the aerospace sector, composite materials have been adopted by several industries. Sectors actively utilizing composites include:

• Aerospace: Valued for their high strength-to-weight ratio, composites like carbon fiber reinforced polymer and aramid reinforced polymer enable the production of lighter, more fuel-efficient aircraft and satellites, contributing to reduced operational costs and increased payload capacities.²
• Automotive: A variety of automotive components, such as chassis and suspension systems, rely on composites for improved safety, fuel efficiency, and performance. Stringent emission regulations are driving this shift, including lightweighting automotive materials for enhanced fuel economy.³
• Renewable Energy: Composites are integral to the renewable energy sector, particularly in the construction of wind turbine blades and solar panel components. Companies are leveraging the dimensional stability, durability, and strength of these materials for operation under harsh environmental conditions, enhancing the longevity and efficiency of renewable energy systems.³
• Construction: Advanced composite materials, such as high-performance concrete mixes and fiber-reinforced polymers, can create structures more resistant to environmental degradation while offering excellent design flexibility. This improves construction longevity, reducing maintenance costs over time.⁴

While composites offer numerous advantages, manufacturers and material scientists face several challenges during their development and manufacturing including:

Designing and Selecting the Right Material

One of the main challenges in composites R&D is the selection of appropriate materials for specific applications. Researchers must consider criteria such as mechanical strength, thermal stability, and environmental resistance, which will entail the careful balancing of trade-offs between different performance characteristics.

Increased Complexity of Material Design

In achieving the desired balance of characteristics, scientists need to precisely control parameters such as filler orientation and distribution. Research has shown that the incorporation of nanofillers into a polymer matrix can bolster its mechanical properties and reduce water absorption in fiber-reinforced composites. As a result, strong interfacial adhesion is established between the matrix and nanofillers, allowing for efficient stress transfer during loading.

However, if not properly managed, the orientation and distribution of fillers within a composite can lead to variations in strength and other properties. The subsequent effect on the interfacial interactions can induce premature failure in the material.⁵

Sustainability

Reinforced polymer composites present several benefits, including the conservation of depleting resources such as metals and alloys. However, their disposal poses significant environmental challenges due to the non-biodegradable nature of petroleum-based polymers and synthetic fibers.

Consequently, research has increasingly focused on developing fully biodegradable and eco-friendly materials known as green composites. The use of green composites has significantly expanded across various engineering disciplines, yet the limited solubility of lignin-based materials for analytical purposes restricts the complete understanding and development of lignin-based green composites.⁶

New Manufacturing Techniques

Techniques like lightweighting and additive manufacturing deliver benefits but also introduce new challenges. Lightweighting replaces heavy materials with lighter-weight composites without compromising strength-to-weight ratios or structures’ fundamental design, while additive manufacturing increases throughput and design complexity. However, researchers must tackle the expensive nature of lightweighting processes, which can also risk impairing the ductility and formability of the materials, as well as concerns regarding the fabrication of composites with long fibers and complex cavities that surround additive manufacturing.^7,8

High Manufacturing Costs

Producing complex composite parts can require costly raw materials, specialized equipment, and skilled labor, leading to high costs. Effective quality control measures are essential to ensure that the final products meet the required standards without excessive waste or rework.⁹

To overcome these challenges, precise material analysis is essential. Key material properties to measure include:

• Glass Transition and Crystallinity: Differential Scanning Calorimetry (DSC) is a powerful technique for measuring the glass transition temperature and crystallinity of composites. These parameters are critical for understanding the thermal and mechanical properties of the material. For example, NASA uses a TA Instruments DSC to determine the quality of thermoplastic composite panels, which is vital for ensuring their performance in space applications.¹⁰ Further examples of real-world composites research using DSC can be found in our blog.
• Cure Kinetics, Cross-Linking, Gelation, and Cure Conversion: DSC paired with LED-PCA accessory can measure cure kinetics and the extent of cross-linking, gelation, and cure conversion in composite materials. These measurements help optimize processing conditions to achieve the desired mechanical properties and durability.^11,12
• Structural Relaxation, Time-Temperature Superposition, and Aging: Dynamic Mechanical Analysis (DMA) provides insights into the viscoelastic behavior of composites, including structural relaxation, time-temperature superposition, and aging effects. This information is key for predicting the long-term performance and stability of composite materials under various, sometime harsh, environmental conditions.¹³ Learn more about DMA testing of composites in this blog.
• Coefficient of Thermal Expansion: Thermomechanical Analysis (TMA) measures the coefficient of thermal expansion, which is important for understanding how composite materials will behave under thermal cycling. This is particularly relevant for applications where materials are exposed to varying temperatures, such as in aerospace and automotive industries.¹⁴

In response to the rising demand for materials that combine superior performance with low weight and cost, the composites market is rapidly expanding. This growth trajectory underscores the importance of addressing inherent challenges in the development and manufacturing of composites, such as selecting and designing appropriate materials, ensuring sustainability, implementing new manufacturing techniques, and managing high production costs.

Advanced material analysis techniques, including DSC, DMA, and TMA, are crucial in overcoming these challenges. These techniques provide critical insights into the thermal and mechanical properties of composites, enabling researchers and manufacturers to optimize processes and achieve the desired performance and durability.

TA Instruments supports composite R&D with cutting-edge material analysis instruments, helping you to overcome the complexities of composite design and manufacturing. By investing in advanced material analysis, companies can lower costs, increase efficiency, and stay competitive in the rapidly evolving composites market.

For more information on how TA Instruments can support the R&D of your composites, visit our composites page or contact us to speak with an expert.

This article explores the intricacies of PCR, challenges in processing, and techniques to verify its suitability for various applications.

As a central pillar of modern society, the pharmaceutical industry bears the load of billions of lives around the world. In 2022, the global revenue of the pharmaceutical industry approximated $1.5 trillion, a figure reflected in two decades of significant growth.¹

Pharmaceutical development is advanced by the continued search for new active pharmaceutical ingredients (APIs), including analogs, phytopharmaceuticals, and biopharmaceuticals, which have the potential to yield life-changing drugs. This enterprise is concomitant with an increasing trend toward designing new dosage forms and drug combinations, improving manufacturing processes, and exploring new indications for existing drugs.

Addressing the needs of the pharmaceutical industry, specifically the research, development and analysis of drugs, requires a sophisticated suite of techniques for fast and effective characterization and quality control. Thermal analysis is a family of techniques that measures the change of specific properties of materials as a function of temperature to elucidate their physical and chemical characteristics.^2,3 While thermal analysis comprises numerous methods, this article will focus on three key examples: differential scanning calorimetry, thermogravimetric analysis, and sorption analysis.

Thermogravimetric analysis (TGA) is a valuable analytical technique employed in pharmaceutical R&D to assess the thermal stability and decomposition behavior of materials. TGA involves subjecting a sample to controlled temperature increases under a controlled atmosphere while continuously monitoring its weight.⁴

Material stability is of paramount importance in pharmaceuticals, as it directly affects product safety, efficacy, and shelf-life. Understanding how a pharmaceutical substance reacts to temperature variations and identifying potential degradation pathways is critical for ensuring the stability of the final product.

TGA offers several benefits to pharmaceutical research and development, including:

• Identifying optimal storage conditions and packaging materials to prevent premature drug degradation through precise degradation measurements
• Determining the moisture content of products, which directly affects chemical stability, API crystal structure, dissolution rate, and compaction.⁵
• Ensuring the development of stable and effective drug formulations by selecting thermally compatible excipients and formulation components.

Providing quality and regulatory compliance when coupled with mass spectrometry Fourier-transform infrared spectroscopy (FTIR). Together, these techniques can detect and quantify volatiles in pharmaceutical samples.

Differential scanning calorimetry (DSC) is a powerful analytical technique widely used in the pharmaceutical industry to characterize APIs and excipients. DSC measures the heat flow associated with temperature changes in a sample during heating, cooling, or remaining isothermal, offering insights into phase/structural changes, chemical reactions, and physical interactions.⁴

During drug research DSC is critical in identifying polymorphs, or different forms of the same chemical compound. Different polymorphs of a drug can exhibit distinct physicochemical properties, such as solubility, dissolution rate, and bioavailability. By subjecting a sample to varying temperatures, DSC can reveal different polymorphs and aid in the selection of the most desirable form, for example, optimizing for enhanced bioavailability and manufacturability.⁴

Additionally, DSC provides critical insights into the glass transition temperature (Tg). This is the temperature at which an amorphous material undergoes a reversible transition from a ductile state to a hard/brittle state or vice versa. The size of the glass transition step is linearly proportional to the amount of amorphous structure in the sample, making it a valuable tool for understanding amorphous content.⁴

Understanding the amorphous content of pharmaceutical solids is advantageous because it can inform decisions to improve the oral bioavailability of poorly water-soluble drugs. Amorphous pharmaceuticals are more soluble and exhibit higher dissolution rates compared to their crystalline counterparts. By monitoring and maintaining amorphous content, DSC can help ensure the stability of these valuable properties.⁴

Another benefit of DSC is its ability to examine material compatibility. In pharmaceutical formulation, it is crucial to ensure that APIs are compatible with excipients, such as bulking agents and lubricants. DSC can detect incompatibilities by revealing shifts or deviations in thermal behavior, helping formulators make informed decisions to avoid potential issues during drug development. These issues could take the shape of unforeseen chemical interactions between excipients and the API, mismatching of physical properties like solubility and dissolution rates, and impairment of the API’s bioavailability.⁴

Finally, knowledge of amorphous content aids in optimizing the lyophilization process. Lyophilization, or freeze-drying, is a crucial step in preserving and transporting pharmaceutical products and ensures the stability and efficacy of the final product. For more information on lyophilization, read our blog, How to Optimize Lyophilization with Thermal Analysis.

Sorption analysis (SA) is a fundamental tool in pharmaceutical R&D used to measure the weight change of a material under water vapor as a function of humidity and temperature. Accordingly, SA helps quantify how moisture is absorbed or desorbed by a drug substance or formulation under various environmental conditions.⁴ This is important because moisture content is a critical factor that affects the stability of solid dosage forms and can adversely impact the efficacy and shelf life of pharmaceutical products by promoting degradation, such as through the hydrolytic degradation of drugs with certain functional groups.⁵

SA can also reveal how water sorption can decrease the glass transition temperature of the amorphous phase in a material. This reduction in Tg can soften the amorphous phase and potentially initiate unwanted crystallization, adversely affecting the product’s properties and stability.

Altogether, understanding the moisture sorption behavior of pharmaceutical products ensures that they maintain their desired characteristics, stability, and effectiveness throughout their shelf life. Furthermore, it allows for optimizing formulation strategies, packaging design, and storage conditions.

Thermal analysis, comprising techniques such as DSC, TGA, and SA, plays an indispensable role in pharmaceutical research, development, and quality control. These methods are part of a comprehensive toolkit for characterizing pharmaceutical materials and ensuring the safety, efficacy, and stability of drug products. While they can be used in isolation, their use in combination can yield deeper insights into pharmaceutical materials. For example, combining DSC and TGA allows for the detailed examination of decomposition behavior and apparent melting.

TA Instruments’ DSC, TGA, and SA technology provide the most accurate and reliable information about pharmaceutical materials, facilitating the development of safe, effective, and stable drug products for patients worldwide.

Contact TA Instruments’ experts today to learn more about how our technology can revolutionize your research and development process, ensuring the highest standards of quality and efficiency.

印刷电路板（PCB）几乎是所有电子应用的支柱。提高 PCB 的性能和可靠性对于 PCB 项目至关重要，更小的印记和更高的可维护性可增强电路板的功能。然而，要确保在不同条件下的使用寿命和性能的一致性，则需要进行详细的分析。

热分析是 PCB 开发过程中的重要工具，该技术可让我们了解材料在不同温度下的行为，以确保材料的稳定性。具体到 PCB，热分析对于评估涂层和粘合剂的固化性能非常重要，而涂层和粘合剂是防止可导致腐蚀和电路板降解的湿气侵入的关键材料。

此外，热分析提供了一种定量方法来比较各种涂层的性能并评估 PCB 材料的固化程度，从而提高生产效率。它还有助于比较层压板和粘合剂在不同温度范围内的性能，降低因热和应力而导致产品失效的风险。最后，热分析支持报废产品的回收利用，例如通过研究由 PCB 废料制成的复合材料。¹

在这里，我们将探索专为 PCB 评估而量身定制的五项关键的热分析技术，阐明它们在提高产品性能和可靠性方面的核心作用。

无论您是从事评估层压板或固化程度的早期产品开发工作，还是专注于评估最终产品稳定性的后期产品开发工作，这五项热分析技术和仪器都可以简化您的工作流程。以下概述了 PCB 热分析的五项关键技术：

热机械分析（TMA）

热机械分析（TMA）非常适合观察玻璃化转变温度附近的材料行为。在研究中，已将 TA 的 TMA 用于跟踪 PCB 树脂玻璃化转变的变化，并将这些变化与表面光洁度和热冲击相关联。²

在一项特定研究中，应用 TA Instruments TMA 分析非导电粘合树脂的化学改性可如何影响与填料分散相关的热性能。³ 该过程包括分析材料的热膨胀性能，然后使用该数据计算热膨胀系数并跟踪玻璃化转变的变化。该评估有助于确定相关材料在特定温度范围内的适用性，以及是否可能因过度膨胀而在 PCB 中产生不需要的应力。

热重分析（TGA）

热重分析（TGA）测量样品重量随温度的变化。TGA 的一项关键应用是评估材料的热稳定性。在一项研究中，研究小组利用 TA TGA 来检测本征黑色聚酰亚胺薄膜的热稳定性。聚酰亚胺薄膜以其优异的环境稳定性而闻名，可用于柔性印刷电路板。该团队的目标是验证生产本征黑色聚酰亚胺薄膜的工艺不会对标准聚酰亚胺薄膜典型的高热稳定性产生负面影响。4 该研究体现了 TGA 在评估材料热特性方面的成效，而材料热特性是 PCB 开发中的一个关键因素。

差示扫描量热法（DSC）

差示扫描量热法（DSC） 是测量固化行为的理想技术，无论固化过程涉及加热还是光照均是如此。DSC 测量提高样品温度所需的热量，是表征转化潜热、材料转化温度和热容等特性的有效方法。

动态力学分析（DMA）

动态力学分析（DMA）分析材料响应如何随外力和温度的变化而变化。其中的一项应用是观察材料如何响应加载和 PCB 的制备而发生变化。该分析还可与提高温度相结合，以更好地了解 PCB 对焊接等工艺的反应。⁵

闪光扩散率

闪光扩散率 是一种常用于测量热扩散率和热导率的方法，因其显著的实验便利性而闻名。在这项技术中，通常应用由激光或氙气源产生的强烈闪光来传递脉冲热量。随后，使用检测器（通常是红外传感器）对热能在材料中的扩散情况进行量化。可根据该数据计算材料的热导率。

闪光扩散率可精确测量热传输并可对 PCB 进行精确表征。一组研究人员使用该技术来研究用作相变材料的镍钛合金的热性能，以改善大功率电子设备的热管理。⁶

热分析方法可帮助 PCB 开发的所有阶段（从原型阶段到最终产品）。上述所有研究均利用了 TA Instruments 业界领先的热分析设备。

由于 TA Instruments 的设备具有卓越的可靠性、测量准确性以及用户友好和高效的操作，行业专业人士通常非常信任 TA Instruments 的设备。请联系 TA Instruments 的电子专家，以了解我们最先进的电子热分析解决方案可如何加快您的产品开发进程，并协助您为客户提供更优质的产品。

我们对复合材料抱有很高的期望：火箭材料需要承受起飞时的高温，风力涡轮机必须能够承受强阵风，运动鞋需要具有长跑所需的耐用性和支撑性。专家如何开发适合此类特定用途的复合材料并验证其性能呢？

复合材料由两种或多种材料组成，这些材料粘合在一起，但在成品结构的宏观或微观尺度上仍然是截然不同的材料。由此产生的复合材料具有不同于任何单一材料的特性。因此，材料科学家需要能够针对特定应用优化复合材料配方，但首先必须进行充分的测试，以验证材料特性。

复合材料开发商利用尖端分析技术满足当今对轻质、可靠产品的高要求。他们首先对材料和产品原型进行表征，以解决客户期望的关键性能属性，包括强度、耐热性、附着力和耐用性。

世界各地实验室的复合材料科学家如何利用材料分析来提高其产品性能？以下是顶尖的材料科学技术以及如何在不同应用和行业中应用这些技术来测试复合材料的真实研究示例：

差示扫描量热仪（DSC）测量与材料的热转变相关的温度和热流。DSC 可量化复合材料的玻璃化转变温度（Tg）、凝胶时间和固化时间等关键指标。

Mohamed Rady 教授在波尔多大学使用 DSC 来支持他对颗粒复合材料相变的研究。¹ 他专门研究了熔化和凝固，设计了一个简单的程序来从 DSC 中获得准确的结果。

保罗萨巴蒂尔大学 CIRIMAT 实验室的研究人员 Rivière、Caussé、Lonjon、Dantras 和 Lacabanne 使用调制 DSC 来研究了在聚合物（聚醚醚酮）基体中添加银纳米粒子的效果。² 准确的热导率和比热测量使他们能够了解材料的热传导机制。他们的数据可用于优化材料的混合，以形成适合特定应用的复合材料。

TA Instruments 的 Discovery DSC 系列配备了专利 Tzero DSC 技术，在基线平坦度、过渡分辨率和灵敏度方面均有所改进，可进行更精确的热流测量。可在 TA DSC 上更快、更准确地运行 Modulated® DSC（MDSC®）实验。多样品 X3 DSC 可独特地同时测量多达三个样品的热流，从而提高生产率。

流变学是研究材料流动和变形的学科。变形和流动分别称为应变和应变率，表示物体在外力或应力的影响下移动的距离。

例如，埃博尼州立大学的 Ogah 教授使用流变仪测量填料和添加剂对木塑复合材料加工的影响。³ Ogah 以热塑性聚合物为基体材料对天然纤维进行加工，创造出天然纤维复合材料。然后，他在 TA Instruments Discovery 混合流变仪上分析了不同的纤维类型、含量、颗粒尺寸和形状对最终复合材料的流变特性的影响。

流变仪具有测量粘度和粘弹性的独特功能。TA Instruments 的 Discovery 混合流变仪还可帮助用户轻松识别粘度计或毛细管流变仪无法研究的微观结构的差异。在研究复合材料如何在微观层面上相互作用时，这些测量尤其有用。

力学测试可帮助研究人员表征材料的机械性能，或确定结构对某种特定力量的反应。复合材料开发人员对材料的失效、疲劳、剪切或蠕变进行量化，并利用这些信息为特定应用设计出更好的产品。

来自阿尔伯塔大学的 Garces 和 Ayranci 开发了一种新方法，他们利用基于挤压的增材制造技术，通过电阻加热来制造和激活形状记忆聚合物复合材料（SMPC）。⁴ 他们使用 TA Instruments 的 ElectroForce 热调节拉伸测试仪评估特定加工条件下的变形对 SMPC 的影响。他们的研究使其他人能够利用该技术成功制造 SMPC，并将其广泛应用于 “生物医学支架、运动器材和无人驾驶飞行器（UAV）”等领域。

无论是开发坚固的建筑材料还是生物相容性骨替代物，世界各地的领先实验室都依靠 ElectroForce 机械测试仪器来验证复合材料的机械性能。ElectroForce 负载框架涵盖了广泛的作用力范围，而多样本疲劳仪器可同时测试多达 16 个样本，因此可加速疲劳研究。

虽然这些研究示例说明了一些可能性，但还有无数的仪器和技术可用于分析复合材料的每种材料属性。在我们的复合材料页面上了解当今的领先技术，并查看哪些仪器符合您在复合材料设计和加工方面的需求。

仍不确定最适合您实验室的技术？请联系 TA Instruments，我们的复合材料专家将很高兴为您指明正确的方向。

消费者兴趣和可持续性发展目标导致对电动汽车的需求飙升。美国的目标是，到 2030 年时电动汽车销量占总市场的 50%，但 99% 的电动汽车电池的原材料和零部件材料均在国外生产。^{1, 2} 采购外国制造的材料和电池已经给该行业带来了挑战。2022 年 3 月，由于俄罗斯入侵乌克兰，电池的主要原料镍的价格暴涨。³

电动汽车制造商对短期内实现全球贸易稳定并不乐观。大众汽车奥迪部门首席执行官 Markus Duesmann 在接受《纽约时报》采访时表示，“在未来几年内，原材料都将是一个问题。” ⁴

美国政府已为支持新型方法做好准备，以实现可持续性国内电池供应。一项 2022 年两党基础设施法案拨款超过 70 亿美元，以帮助创建成本更低、中断更少、产速更快的美国电池供应链。⁵

现在，国内电池生产的未来掌握在电池研究人员和制造商的手中。电动汽车电池行业正采用新技术和新工艺来完成看似不可能完成的任务：在不依赖外国贸易的情况下制造可靠的电池。以下是领先的电动汽车电池制造商已推行的可持续性国内电池生产的方式，以及分析技术在这一进程中发挥的关键作用。

为规避供应链问题以及降低成本，顶级电动汽车原始设备制造商（OEM）正在转向生产自己的电池。通用汽车研发部电池系统研究总监 Mei Cai 博士在佛罗里达州奥兰多举行的 “2022 年国际电池研讨会和展览会 (the International Battery Seminar and Exhibit 2022)”上介绍了通用汽车 (GM) 在电池制造方面的工作。

Cai 博士解释说：“通用汽车内部电池研发的重中之重是能量密度，即电池可以以轻便的形式储存多少能量。” 提高能量密度会降低成本。该团队正在探索固体锂阳极和固体电解质界面膜，以实现最高的能量密度和最低的成本。一旦通用汽车在电池研发方面取得成功，他们计划将电池设计应用于在电动汽车之外的领域并实现盈利。

电池制造商如何在国内生产高性价比、高能量密度电池的竞争中获胜？热分析为有效的材料选择和电池设计提供了重要的数据。通过热分析确保电池在各种条件下的安全性和性能，是创建功能性、革命性电池设计的第一步。流变学可用于优化电池浆料配方，是确保电极制造稳定性和可加工性的关键步骤。

由于对传统锂离子电池材料（锂、钴、镍和石墨）的需求量巨大，电池研究人员正在探索可持续性替代品。Group14 Technologies 和 Sila Nanotechnologies 正在拓展他们在硅基阳极材料方面的工作，该材料具有可超越当前石墨材料的应用潜力。⁶

使用新型电池材料可释放出更为顺畅的国内生产的潜能，同时可提高安全性和性能。研究人员在实际操作条件下使用热分析技术来研究应用创新材料的电池设计。例如，国家可再生能源实验室 (the National Renewable Energy Laboratory) 的 M. C. Schultz 等人使用他们的 TA Instruments DSC 和 TGA 来研究涂层对硅阳极材料的影响。⁷ DSC 和 TGA 常用于电池研究，以验证新材料是否可增强电池的运行和安全性。

当锂离子电池达到使用寿命时，如何避免浪费其宝贵的材料？电池材料短缺可通过重复使用旧电池中的原材料来解决。在国内回收电池是最有效的方法，因为这样做既可以降低排放和运输成本，同时也可以加强国内电池材料供应链。⁸

与任何回收系统一样，将回收材料纳入新产品需要对材料进行彻底的表征。电池内的电化学过程会如何改变材料？它们是否因电池误用或损坏而变形？材料分析技术可帮助电池开发人员确保回收材料可提供必要的热学和物理学特性，以支持新的功能性电池。

尽管需要克服挑战，但也存在巨大的机遇。电动汽车制造商有机会将电池生产掌控在自己手中，因此他们可以克服供应链的不稳定性问题并监督电池生产的方方面面。目前采用新型材料和可回收材料的电池制造商将为未来几十年的生产融入可持续性和可靠性。

任何主要的供应链转变都需要严格的质量控制和测试。正如上面提到的例子，电池材料测试是发展可持续性国内电池生产的关键步骤。从材料选择到电池安全测试，这些技术将成为国内电池设计和制造的支柱。点击此处以了解有关电池材料测试的更多信息，并了解这些技术将如何支持可持续性国内电池生产的未来。