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Structure and Morphology Development in Films of mLLDPE/LDPE Blends During Blowing
Author(s) -
Silvestre Clara,
Cimmino Sossio,
Raimo Maria,
Duraccio Donatella,
del Amo Fernandez Bernardo,
Lafuente Pilar,
Sanz Virginia Leal
Publication year - 2006
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.200600239
Subject(s) - low density polyethylene , materials science , spherulite (polymer physics) , composite material , morphology (biology) , haze , rheology , blow molding , relaxation (psychology) , linear low density polyethylene , polymer chemistry , polymer , organic chemistry , chemistry , psychology , mold , social psychology , genetics , biology
Summary: In this work the analysis of the structure orientation, morphology, relaxation time and optical properties of blown films of mLLDPE, LDPE and their blends were performed by using WAXD, SALS, AFM, DSC and rheological and haze tests. For mLLDPE film, the crystals do not present “ a ”‐axis orientation along the machine direction; a distinct spherulite like superstructure is seen. The film surface is very rough. The values of bulk and surface haze are higher than LDPE and blends, whereas the relaxation time is lower. For LDPE film the (110) planes are parallel and at same time twisted with respect to the layer of the film with the “ a ”‐axis well oriented along the machine direction. No spherulite superstructure is observed and the surface of the film is more regular. High values of relaxation time are observed. The surface haze is the predominant contribution to the total haze. For the blend films no clear and distinct spherulite structures are observed. The orientation degree increases with composition never approaching that of LDPE. The surface is very more regular and smooth than that of the pure polymers. The haze values are below the values of pure materials. It was underlined that bulk and surface morphology and orientation degree of the crystalline planes along the machine direction dictate the optical properties of the films. Moreover both orientation and morphology are defined by the PE molecular and melt rheology characteristics, processing conditions and blend composition.Total, bulk and surface haze of mLLDPE/LDPE blend films as a function of composition.