TY - JOUR
T1 - High-strength welds in metallocene polypropylene/polyethylene laminates
AU - Chaffin, Kimberly A.
AU - Knutsen, Jeffrey S.
AU - Brant, Patrick
AU - Bates, Frank S.
PY - 2000/6/23
Y1 - 2000/6/23
N2 - Spectacular advances in organometallic chemistry over the past two decades have resulted in single-site catalysts that are revolutionizing production of polyethylene (PE) and isotactic polypropylene (iPP). This report describes an unanticipated benefit of metallocene-catalyzed semicrystalline polyolefins, namely welded joint strengths in PE/iPP laminates that can exceed the cohesive strength of the constituents. We propose that interfacial polymer entanglements, established in the molten state and subsequently anchored in chain-folded lamellae upon crystallization, are responsible for this intrinsic property. The poor adhesion exhibited by traditional Ziegler-Natta-catalyzed polyolefins is shown to derive from the accumulation of amorphous polymer, a by-product of the polymerization reactions, at the interface. These results should facilitate fabrication and improve the properties of composites based on materials that dominate the plastics industry.
AB - Spectacular advances in organometallic chemistry over the past two decades have resulted in single-site catalysts that are revolutionizing production of polyethylene (PE) and isotactic polypropylene (iPP). This report describes an unanticipated benefit of metallocene-catalyzed semicrystalline polyolefins, namely welded joint strengths in PE/iPP laminates that can exceed the cohesive strength of the constituents. We propose that interfacial polymer entanglements, established in the molten state and subsequently anchored in chain-folded lamellae upon crystallization, are responsible for this intrinsic property. The poor adhesion exhibited by traditional Ziegler-Natta-catalyzed polyolefins is shown to derive from the accumulation of amorphous polymer, a by-product of the polymerization reactions, at the interface. These results should facilitate fabrication and improve the properties of composites based on materials that dominate the plastics industry.
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U2 - 10.1126/science.288.5474.2187
DO - 10.1126/science.288.5474.2187
M3 - Article
AN - SCOPUS:0034705627
SN - 0036-8075
VL - 288
SP - 2187
EP - 2190
JO - Science
JF - Science
IS - 5474
ER -