TY - JOUR
T1 - HDPE liquefaction
T2 - Random chain scission model
AU - Rangarajan, Priya
AU - Bhattacharyya, Dibakar
AU - Grulke, Eric
PY - 1998/11/7
Y1 - 1998/11/7
N2 - Liquefaction of commodity polymers to oils and gases can be used to recover the energy value of these materials. This article reports liquefaction data for high-density polyethylene (HDPE), one of the major plastics in recycled material. Thermal degradation of HDPE to oil-gas mixtures required higher temperatures (450-490 °C) than low-density polyethylene (LDPE) (430-460 °C) because of fewer chain branching points for HDPE, which are more susceptible to chain scission reactions. The addition of hydrogen (0.1-1.5 MPa) had negligible effect on product distribution. HDPE thermal degradation is consistent with a random chain scission mechanism. Product distributions for degradation at 450 °C were modeled assuming random chain scission with a rate constant k(x) dependent on the molecular weight x by a power law model dependence, k(x) = kb xb, where kb is the pseudo-first-order rate constant, and b is the power index of dependence on molecular weight. Degradation rates dropped rapidly after initial breakup of the chains, and 2 sets of coefficients were needed to describe the molecular weight distributions as functions of reaction time. The error in model was about 10%. This model can be used to optimize the production of oils from thermal degradation of HDPE.
AB - Liquefaction of commodity polymers to oils and gases can be used to recover the energy value of these materials. This article reports liquefaction data for high-density polyethylene (HDPE), one of the major plastics in recycled material. Thermal degradation of HDPE to oil-gas mixtures required higher temperatures (450-490 °C) than low-density polyethylene (LDPE) (430-460 °C) because of fewer chain branching points for HDPE, which are more susceptible to chain scission reactions. The addition of hydrogen (0.1-1.5 MPa) had negligible effect on product distribution. HDPE thermal degradation is consistent with a random chain scission mechanism. Product distributions for degradation at 450 °C were modeled assuming random chain scission with a rate constant k(x) dependent on the molecular weight x by a power law model dependence, k(x) = kb xb, where kb is the pseudo-first-order rate constant, and b is the power index of dependence on molecular weight. Degradation rates dropped rapidly after initial breakup of the chains, and 2 sets of coefficients were needed to describe the molecular weight distributions as functions of reaction time. The error in model was about 10%. This model can be used to optimize the production of oils from thermal degradation of HDPE.
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U2 - 10.1002/(SICI)1097-4628(19981107)70:6<1239::AID-APP20>3.0.CO;2-T
DO - 10.1002/(SICI)1097-4628(19981107)70:6<1239::AID-APP20>3.0.CO;2-T
M3 - Article
AN - SCOPUS:0032494656
SN - 0021-8995
VL - 70
SP - 1239
EP - 1251
JO - Journal of Applied Polymer Science
JF - Journal of Applied Polymer Science
IS - 6
ER -