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Structure and properties of polypropylene/low‐density polyethylene blends grafted with itaconic acid in the course of reactive extrusion
Author(s) -
Krivoguz Y. M.,
Pesetskii S. S.,
Jurkowski B.,
Tomczyk T.
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.23998
Subject(s) - low density polyethylene , differential scanning calorimetry , materials science , reactive extrusion , polyethylene , polypropylene , glass transition , polymer chemistry , polymer , extrusion , polymer blend , composite material , chemical engineering , thermodynamics , copolymer , physics , engineering
This study was concerned with the structural features and mechanical properties of polypropylene (PP)/low‐density polyethylene (LDPE) blends, which after compounding were modified by the free‐radical grafting of itaconic acid (IA) to produce [PP/LDPE]‐ g ‐IA in the course of reactive extrusion. To analyze the structural features of the [PP/LDPE]‐ g ‐IA systems, differential scanning calorimetry and relaxation spectrometry techniques were used. The data were indicative of the incompatibility of PP and LDPE in the [PP/LDPE]‐ g ‐IA systems on the level of crystalline phases; however, favorable interactions were observed within the amorphous phases of the polymers. Because of these interactions, the crystallization temperature of PP increased by 5–11°C, and that of LDPE increased by 1.3–2.7°C. The rapprochement of their glass‐transition temperatures was observed. The single β‐relaxation peak for the [PP/LDPE]‐ g ‐IA systems showed that compatibility on the level of structural units was responsible for β relaxation in the homopolymers used. Variations in the ratios of the polymers in the [PP/LDPE]‐ g ‐IA systems led to both nonadditive and complex changes in the viscoelastic properties as well as mechanical characteristics for the composites. Additions of up to 5 wt % PP strengthened the [PP/LDPE]‐ g ‐IA blended systems between the glass‐transition temperatures of LDPE and PP. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1746–1754, 2006