DOES COCOMBUSTION OF PVC AND OTHER PLASTICS LEAD TO ENHANCED FORMATION OF PCDD F/

Co-combustion of PVC together with further common plastics were perfor med in a gramme scale micro combustion apparatus to investigate whethe r PCDD/F-formation is influenced hereby. Materials applied were polyet hylene (PE), polystyrene (PS), polyurethane (PUR), epoxy- and phenol/f ormaldehyde resin (Epox and Ph). These co-combustion experiments yield ed mainly PCDF in the high mu g/kg range. Correlation between structur al features of co-combusted plastics and PCDD/F formation could be obt ained for PE and PS, with PS showing higher values due to its aromatic sidegroups. More detailed investigations on the combustion kinetics r evealed that HCl and hydrocarbons are not formed at the same time duri ng burning process even in the case of PVC. Therefore, combustion expe riments were also performed in the presence of additional HCl usually yielding higher amounts of PCDD/F. Further experiments showed that PCD D/F formation does not depend on the distance between the co-combusted materials indicating that PCDD/F-formation takes place in a gas phase reaction exclusively. (C) 1998 Elsevier Science Ltd. All rights reser ved.