How We Measure Q10 Values and Activation Energies

To understand how materials age over time, we analyze Q10 values (the factor by which aging rates increase with a 10°C temperature rise) and activation energies (the energy barrier for aging reactions). Our approach combines advanced analytical techniques to study multiple aging mechanisms, including hydrolysis, oxidation, and physical aging, while also capturing how these processes may interact and trigger one another.

Our Methodology

We employ Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) in a frequency sweep protocol to measure aging rates across a range of conditions. Here’s how it works:

1. Frequency Sweep with DSC:

   • DSC measures the heat flow associated with material transitions, allowing us to detect changes in thermal properties caused by aging.

   • By applying a frequency sweep (varying the rate of temperature oscillations), we probe the kinetics of aging mechanisms at different timescales. This helps us quantify reaction rates and determine Q10 values by comparing aging rates at different temperatures.

   • Activation energies are calculated using the Arrhenius equation, derived from the temperature dependence of reaction rates observed in DSC data.

2. FTIR Analysis:

   • FTIR spectroscopy identifies chemical changes in the material by analyzing molecular bond vibrations.

   • We track specific spectral peaks associated with aging mechanisms, such as the formation of carbonyl groups (oxidation) or loss of hydroxyl groups (hydrolysis). This provides insights into the chemical pathways driving material degradation.

   • By correlating FTIR data with DSC results, we gain a comprehensive view of both physical and chemical aging processes.

3. Studying Multiple Aging Mechanisms:

   • Hydrolysis: We monitor water-induced bond cleavage, which weakens material structure.

   • Oxidation: We track oxygen-driven reactions that form degradation products, often accelerating other mechanisms.

   • Physical Aging: We measure changes in molecular mobility and relaxation, which affect material properties without chemical alteration.

   • Using DSC, DMA and FTIR, we quantify the rates of these mechanisms under controlled conditions (e.g., temperature, humidity, and oxygen exposure).

4. Capturing Interplay Between Mechanisms:

   • Aging processes can interact, where one mechanism triggers or accelerates another. For example, oxidation may produce reactive species that catalyze hydrolysis, or physical aging may alter a material’s susceptibility to chemical degradation.

   • Our frequency sweep approach, combined with DSC and FTIR, allows us to isolate individual mechanisms and study their synergistic effects. By analyzing reaction kinetics and chemical signatures, we can model how these interactions influence overall aging behavior.

Why This Matters

By systematically collecting Q10 values and activation energies, we provide precise data on how materials perform under various environmental stresses. This information is critical for predicting long-term material stability, optimizing formulations, and designing durable products. Our integrated DMA-DSC-FTIR methodology ensures a thorough understanding of complex aging dynamics, including the interplay of multiple degradation pathways.