Morphology and properties of LDPE/EVOH blends = LDPE/EVOH 블렌드의 몰폴로지와 물성에 관한 연구

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Compatibilization of low density polyethylene (LDPE)/ethylene-vinyl alcohol (EVOH) (70/30wt%) blends was investigated in terms of morphology, crystallization and melting behavior, rheological, and tensile properties. Maleic anhydride grafted linear low density polyethylene (LLD-g-MAH) was applied at various concentrations (from 1 to 12phr). Interesting effect of compatibilization on the crystallization kinetics of the blends was noted, and the correlation between morphology and rheological and tensile properties was also discussed. Morphological analysis showed that the blends exhibited a more regular and finer dispersion of EVOH phase when LLD-g-MAH was added. Nonisothermal crystallization exotherms of the compatibilized LDPE/EVOH blends showed the retarded crystallization of the dispersed EVOH phase, which was probably resulted from the constraint effect of the grafted EVOH (EVOH-g-LLD) as well as the size reduction of EVOH domains. The blends exhibited the increased melt viscosity and storage modulus and also the enhanced tensile properties with the addition of LLD-g-MAH, which seemed to be attributable to both dispersed particle size reduction and improved interfacial adhesion. Morphology and oxygen barrier properties of LDPE/EVOH blends have been studied. Laminar dispersion of EVOH with high oxygen barrier properties was obtained in the matrix of LDPE when extruded through an annular blown film die. Various laminar morphologies were observed and the main factors determining the morphology of the blends were composition, viscosity ratio of the components, processing conditions, and compatibilizer level. Oxygen permeation tests have shown that in contrast to spherical dispersion, the unusual high barrier effects were obtained for laminar dispersion which acted as barrier to the permeant molecule by providing a long tortuous path and thinner and longer EVOH layers in larger numbers were more effective in reducing the oxygen permeability. The oxygen permeabil...
Advisors
Kim, Sung-Chulresearcher김성철researcher
Description
한국과학기술원 : 화학공학과,
Publisher
한국과학기술원
Issue Date
1997
Identifier
113077/325007 / 000935254
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학공학과, 1997.2, [ xiii, 132 p. ]

Keywords

Oxygen barrier properties; Laminar morphology; Retarded crystallization; Compatibilization; Hybrid EVOH/Nylon dispersed phase; 혼성EVOH/Nylon분산상; 산소차단성; 판상구조; 지연결정화; 상용화

URI
http://hdl.handle.net/10203/28754
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=113077&flag=dissertation
Appears in Collection
CBE-Theses_Ph.D.(박사논문)
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