Case Study Using Differential Scanning Calorimeter (DSC)
The customer had a product made from a thermoset polymer which needed to be heat cured and the client wanted to experiment with the best, most accurate and most efficient heat cycles for a complete cured product.
The customer provided uncured samples and several samples which had previously been exposed to 177°C for a few minutes. Was this hot enough or long enough for the proper cure?
What NH Chemical Analysis Team Did
The staff needed to understand several key factors for this particular problem.
- What are the properties of the polymer used?
- What is the exotherm cure maximum temperature?
- Did pre-treating offer any advantages to the cure process?
- What was time and temperature required to "cure?"
The team first scanned each of the samples (raw and pre-treated) using a Differential Scanning Calorimeter (DSC). What we discovered was the cure exotherms for all samples were nearly identical. Minimal differences existed between the raw untreated samples and the lightly treated samples, neither of which would be considered cured for the application.
Secondly, the team discovered for this particular polymer that the exotherm cure temp was centered at 260°C, which means that the maximum cure rate is achieved at temperatures of at least 260°C.
This explains why none of the samples they provided had achieved any significant degree of cure: the temperature they were using was about 83°C too low.
Customer Benefit and Result
The customer now knows the proper cure procedure for this application using this polymer. Without adding engineering to the application or a different polymer mix, the standards will remain intact and are fully documented for the lifecycle of the product.