MALDI-TOF Characterization and Cross-Linking Study of Some Novel Polycyclic Carbonates

Abstract

Attempts were made to synthesize polycyclic carbonates by reacting C-C orthocoupled 4-t-butylphenol resins with excess triphosgene under high-dilution conditions. Under these conditions complete functionalization of the phenolic groups was not possible because of steric hindrance. Novolac-type phenol-formaldehyde resins were selected for this study because there is less steric hindrance in these systems toward the formation of the cyclic carbonates. The MALDI-TOF MS technique plays a crucial role in the detection of the absolute masses of the different oligomeric polycyclic carbonates formed. The functionalization of the hydroxy groups by formation of cyclic carbonates has also been confirmed by NMR. Our objective in the synthesis of these types of polycyclic carbonates was to obtain therming materials with a high cross-link density. When mixed with a commercial BPA polycarbonate (M _w = 33 000) transesterification reactions take place resulting in a cross-linked system. The polycyclic carbonates were mixed with the linear polycarbonate in different proportions and cured at different temperatures by using lithium stearate as catalyst. Curing a mixture which contained 10 wt% of the polycyclic carbonates at 350 °C for 30 min resulted in a highly cross-linked system.

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