(A) study on the properties of PLLA/clay nanocomposites using in-situ polymerized polylactide/clay masterbatches = In-situ 중합에 의한 폴리락타이드/유기화 점토 매스터배치를 이용한 PLLA/유기화 점토 나노복합체의 물성에 대한 연구

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Six kinds of organifiers having different soft segments and molecular weight were synthesized from three kinds of polyols (PTMG, PEA and PCL) and it was confirmed that the successful formation of urethane linkage in organifiers by FT-IR. Six kinds of organoclays were prepared by using synthesized organifiers to investigate the effects of molecular weight and the chemical structure of organifiers. PTMG based organoclays showed higher ion-exchanged fraction than other organoclays and long chain organifier showed better efficiency in ion-exchanged fraction in the case of PTMG based organifiers. From WAXD and TEM analysis, it was confirmed that PTMG based organoclays formed exfoliated silicate layer structures. Three types of PLA/clay masterbatches were prepared by $\It{in-situ}$ ring-opening polymerization of stereoisomers of lactide with PTMG based organoclay or commercial organoclay $(Cloisite\reg 30B)$ as macro-initiators in the presence of equimolar $Sn(Oct)_2/PPh_3$ complex catalysts. The molecular weight of PLA/clay masterbatches decreased with increasing organoclay content because organoclay had hydroxyl terminal groups which can initiate the ring-opening polymerization of lactide. Thermal stabilities of PLA/clay masterbatches improved with increasing organoclay content because silicate layers acted as heat and mass transport barriers. As organoclay content increased, Tg and Tm decreased because molecular weight of PLA segment decreased. From WAXD and TEM analysis, all the PLA/clay masterbatches showed partially exfoliated silicate layers. Finally, PLLA/clay nanocomposites were prepared by melt mixing of commercial PLLA resin and different types of PLA/clay masterbatches having similar molecular weight in the Brabender counter-rotating mixer. Each type of PLA/clay masterbatches contained PTMG based organoclay in 3 wt% on the basis of inorganic. For comparative study, PDLA without clay and PDLA/clay masterbatch loaded with $Cloisite\reg 30B$ were also us...
Advisors
Kim, Sung-Chulresearcher김성철researcher
Description
한국과학기술원 : 생명화학공학과,
Publisher
한국과학기술원
Issue Date
2010
Identifier
418696/325007  / 020065828
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 생명화학공학과, 2010.2, [ x, 119 p. ]

Keywords

clay; PLA; Polylactide; nanocomposite; 나노복합체; 유기화 점토; 클레이; 폴리락타이드

URI
http://hdl.handle.net/10203/29078
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=418696&flag=dissertation
Appears in Collection
CBE-Theses_Ph.D.(박사논문)
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