Quantitative Analysis of High Molecular Weight Antioxidant in Semiconductive Cable Materials

The polymeric antioxidant is segmented into monomeric units through chemical decomposition. The patent employs a two-stage decomposition process: first treating with boron trifluoride to break polymer chains, then using sodium hydroxide to further decompose into detectable monomeric fragments. This segmentation transforms the undetectable polymeric form into multiple detectable monomer peaks that can be quantified individually and summed for total antioxidant content.

Chemical reagents serve as intermediaries to transform the antioxidant into a detectable form. Boron trifluoride acts as an intermediary catalyst to initiate polymer chain scission, while sodium hydroxide serves as an intermediary base to complete the decomposition and stabilize the resulting monomeric fragments. These intermediaries enable the conversion of the undetectable polymeric antioxidant into detectable monomeric units without directly measuring the polymer itself.

Chemical decomposition is performed as a preliminary action before the actual GC detection step. The patent requires pre-treatment of the sample with boron trifluoride followed by sodium hydroxide to decompose the polymeric antioxidant into monomers. This preliminary decomposition ensures that when the sample enters the GC system, only detectable monomeric units are present, eliminating the problem of polymeric forms producing multiple unresolved peaks.

The chemical structure parameter of the antioxidant is changed from polymeric to monomeric form through controlled decomposition. By changing the molecular weight parameter from high (polymeric) to low (monomeric), the antioxidant becomes detectable as discrete peaks in GC analysis. The patent controls this parameter change through staged chemical treatment with specific reagents at controlled temperatures and times.