Process for treating materials containing CH polymer chains comprising the following steps: by external means, triggering combustion of the material in an environment insulated from the outside; drawing off the gaseous combustion products from said environment to put it under vacuum; feeding combustion-supporting gas in a quantity insufficient to create centers of combustion while maintaining the environment under vacuum in order to favor a process of molecular decomposition of the material; subjecting the produced gases to condensation and collecting the condensate in a non-pressurized environment.