Chemical reaction networks govern polymer degradation and contain critical design information regarding specific susceptibilities, degradation pathways, and degradants. However, predicting reaction pathways and characterizing complete reaction networks has been hindered by high computational costs because of the vast number of possible reactions at deeper levels of network exploration. Here, we show that an exploration policy based on Dijkstra’s algorithm and using the reaction rate as a cost function provides a tractable means of exploring the pyrolytic degradation network of a representative commodity polymer, polyethylene glycol (PEG). The resulting network is the largest reported to date for this system, and includes pathways out to all degradants observed in earlier mass spectrometry studies. The initial degradation pathway predictions were validated by complementary experimental analysis of pyrolyzed PEG samples by electrospray ionization mass spectrometry (ESI-MS). These
findings demonstrate that reaction network characterization is reaching sufficient maturity to be used as an exploratory tool for investigating materials degradation and interpreting experimental degradation studies.

Efficient exploration of large chemical space by a modified Dijkstra’s algorithm

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