Effects of reactive melt mixing on the morphology and thermal behavior of linear low-density polyethylene/rubber blends

• Published in: Journal of applied polymer science Vol. 109; no. 2; pp. 1014 - 1021
• Main Authors: Penco, Maurizio, Sciucca, Stefania Della, Passaglia, Elisa, Giordani, Guido, Coiai, Serena, Di Landro, Luca
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15-07-2008; Wiley
• Subjects: Applied sciences; blends; Chemical reactions and properties; Crosslinking, vulcanization; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; polyethylene (PE); reactive processing; thermal properties; Condensation reaction; Polymer blends; Graft copolymer; SBS; polyethylene (PE); Thermoplastic rubber; reactive processing; Crystallinity; Experimental study; Property processing relationship; Heterogeneous mixture; Thermal properties; Structure processing relationship; Vulcanization; Triblock copolymer; Chemical modification; Morphology; Olefin polymer; Linear low density ethylene polymer; Organic peroxide; blends
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.28108

Linear low-density polyethylene (LLDPE)/polybutadiene (PB) and LLDPE/poly(styrene-b-butadiene-b-styrene) (SBS) binary blends were prepared by simple melt mixing or by reactive blending in the presence of a free-radical initiator, and for comparison, pure LLDPE was treated under the same conditions with a comparable free-radical initiator concentration. The effect of the reactive melt mixing on the morphology of the blends was studied with transmission electron microscopy, and the corresponding particle size distributions were analyzed and compared to highlight the effects of the crosslinking and grafting phenomena. Thermal properties of the obtained materials were investigated with differential scanning calorimetry and dynamic mechanical thermal analysis (DMTA). In particular, the effect of the reactive mixing parameters on the amorphous phase mobility was investigated. The influence of the chemical modification on the crystallization behavior of LLDPE, neat and blended with PB and SBS, was also studied with dynamic and isothermal differential scanning calorimetry tests, and the isothermal thermograms were analyzed in light of the Avrami equation.