Analysis of TNPP in LLDPE formulations: did the phosphite hydrolyze during processing?

摘要

This report describes a simple solvent-based technique for the separation of tris(nonylphenyl) phosphite (TNPP) from a LLDPE (linear-low density polyethylene) resin, as well as subsequent analysis. The solvent "extracts" were analyzed as is using 31{sup left}P-NMR and/or liquid chromatography techniques. The analytical results showed that the main reaction product formed during the compounding step was tris(nonylphenyl) phosphate (P{sup}V) by way of phosphite (P{sup}III) oxidation. It was, further, shown that the phosphite did not undergo any hydrolysis reaction, as determined by analyzing for nonylphenol and "acid phosphite" levels. Lastly, the HPLC method was shown to be viable in the concurrent analysis for both components in typically used phenolic and phosphite antioxidant blends.