摘要
Depolymerization of polybutylene terephthalate (PBT) in supercritical methanol was studied using a stainless stirred batch\|type autoclave under high temperature (453～533?K) and high pressure (7～12?MPa) conditions.The main depolymerization products were dimethyl terephthalate (DMT) monomer and ethylene glycol.The effects of different reaction temperature and pressure on depolymerization of PBT were investigated by analysis of the solid phase and liquid phase products.Considering the critical point of methanol (512 6?K,8 09?MPa),the reaction pressure was varied with in the range of 7～12?MPa.The results showed that the reaction pressure had little influence on the depolymerization and the depolymerization rate was affected greatly by the reaction temperature.The depolymerization of PBT was only 30% in 40?min at lower temperatures (453～463?K) but reached 100% in 20?min when the temperature was above 513?K.Depolymerization kinetics of polybutylene terephthalate in supercritical methanol was studied.The results showed that the depolymerization reaction rate constant ( k 1) in the temperature range of 513～533?K was much larger than the rate constant ( k 2) in the range of 453～483?K.The dissolution characteristics of PBT in supercritical methanol were the critical factors for depolymerization of PBT in a short time.These findings suggest that the supercritical methanol treatment for depolymerization of polymers such as PBT will be potential for obtaining useful chemicals.
Depolymerization of polybutylene terephthalate (PBT) in supercritical methanol was studied using a stainless stirred batch-type autoclave under high temperature (453 similar to 533 K) and high pressure (7 similar to 12 MPa) conditions. The main depolymerization products were dimethyl terephthalate (DMT) monomer and ethylene glycol. The effects of different reaction temperature and pressure on depolymerization of PBT were investigated by analysis of the solid phase and liquid phase products. Considering the critical point of methanol (512.6 K, 8.09 MPa), the reaction pressure was varied with in the range of 7 - 12 MPa. The results showed that the reaction pressure had little influence on the depolymerization and the depolymerization rate was affected greatly by the reaction temperature. The depolymerization of PBT was only 30% in 40 min at lower temperatures (453 similar to 463 K) but reached 100% in 20 min when the temperature was above 513 K. Depolymerization kinetics of polybutylene terephthalate in supercritical methanol was studied. The result's showed that the depolymerization reaction rate constant (k(1)) in the temperature range of 513 - 533 K was much larger than the rate constant (k(2)) in the range of 453 483 K. The dissolution characteristics of PBT in supercritical methanol were the critical factors for depolymerization of PBT in a short time. These findings suggest that the supercritical methanol treatment for depolymerization of polymers such as PBT will be potential for obtaining useful chemicals.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2005年第2期309-312,共4页
Acta Polymerica Sinica
基金
国家自然科学基金 (基金号 2 0 0 760 13 )资助项目
