THERMOLYSIS OF ACETYLENE-TERMINATED SULFONE RESINS .2. OLIGOMERIC ANDRESIDUAL PRODUCTS OF DEGRADATION

Resins from acetylene terminated sulfone (ATS) fractions and related m odel compounds have been pyrolysed to 1000-degrees-C under high vacuum conditions. The residual and oligomeric product fractions of degradat ion were isolated using the technique of thermal volatilization analys is (TVA). The residues from degradation were weighted and subjected to compositional analysis by infrared (IR) spectroscopy. The oligomeric products of degradation were weighted, isolated into preparative TLC b ands, and identified through the joint application of IR and proton nu clear magnetic resonance (NMR) spectroscopies and chemical ionization mass spectroscopy (CIMS). The residues from thermal degradation proved somewhat intractable. On the other hand, analysis of the oligomeric p roduct fractions provided a wealth of identifiable derivatives which c onfirmed the major role that random scissions play in the degradation process. Residue yields were shown to increase with the polyene concen tration in the cured resin. In contrast, the yields of oligomeric prod ucts were shown to be inversely related to polyene concentration in th e cured resin. ATS and ATB resin were also aged at 250-degrees-C and a t 300-degrees-C in air. Both resins were stable to weight loss at 250- degrees-C but ablated slowly at 300-degrees-C in air. The ageing proce ss was accompanied by oxidation of the polyene to carbonyl containing derivatives which are stable at 250-degrees-C but unstable at 300-degr ees-C. The AT resins were significantly more stable to weight loss tha n epoxy resins containing similar structural motifs.