High Temperature Non Aqueous Volatile Acid Titration in Recycled Polyethylene
High temperature non-aqueous titration strips volatile carboxylic acids from hot PE melt into organic media to quantify corrosion risks and thermal stability.
Carboxylic Acid Quantification
Meaning
Chemical analysis determines the concentration of specific organic acid groups within the molecular structure of a polymer chain. Through carboxylic acid quantification, technicians assess the terminal end groups in resins such as polyethylene terephthalate. This measurement reveals the chemical reactivity and potential for further chain extension during processing.
It is a critical metric for predicting how a material will behave when subjected to high heat in a molding machine.
Analytical Technique
Potentiometric titration in non-aqueous solvents offers a precise way to identify these functional groups. The carboxylic acid quantification procedure involves dissolving the polymer in a mixture of benzyl alcohol and chloroform. Accurate results require careful temperature control to prevent side reactions.
Polymer Stability
High concentrations of acidic end groups accelerate the rate of hydrolytic degradation when the resin is exposed to heat and moisture. During carboxylic acid quantification, a low reading suggests that the material will maintain its molecular weight through multiple heat cycles. Stability in the melt is a requirement for producing thin-walled parts.
Reaction Control
Producers monitor these values to ensure that the polycondensation process has reached the target completion level. This metric provides a more detailed view of the polymer chemistry than simple melt flow index tests.