The study of polymers by high-temperature ATR spectroscopy

A new high-temperature attenuated total reflectance apparatus (HATR) was constructed and used at different temperatures for making infrared measurements on the same liquid or solid sample. It was found that this method was applicable to the continuous quantitative analysis of changes occurring during chemical reactions such as polymerization, isomerization, and crosslinking. In the bulk polymerization of styrene, the process of monomer consumption could be followed progressively. In the crosslinking reaction of high cis-polybutadiene by sulfur-accelerator or peroxide crosslinking systems, the decrease of cis content and its partial isomerization to trans structure was measured. Furthermore, in the crosslinking reaction of ethylene–propylene terpolymers (EPDM), the consumption of double bonds was observed over the course of the reaction with both sulfur-accelerator and peroxide crosslinking systems. The effect was greatest in the case of methylenenorbornene-type EPDM.