Selective Localization Behavior of Carbon Nanotubes: Effect on Transesterification of Immiscible Polyester Blends
writer：Defeng Wu, Yurong Sun, Dongpo Lin, Weidong Zhou, Ming Zhang, Lijuan Yuan
keywords：carbon nanotubes; polycarbonate (PC); poly(trimethylene terephthalate) (PTT); transesterification; morphology.
source：期刊
specific source：Macromolecular Chemistry & Physics
Issue time：2011年
Macromolecular Chemistry & Physics, 2011, 212(15), 1700-1709
ABSTRACT:
The selective localization of carbon nanotubes (CNTs) in an immiscible polymer blend has attracted much attention. If the two component polymers could react with each other, whether the selectively located CNTs affect those reactions or not? This is very interesting and worthy of study. In this work, therefore, an immiscible polyester blend based on polycarbonate/poly(trimethylene terephthalate) (PC/PTT) with a blend ratio of 60/40 (w/w) was chosen as the target blend system for the study. During melt mixing, tetra-n-butyl titanate (Ti(OBu)4) was first introduced into the system to depolymerize the two polymers and to enhance their reactive ability, and after a period of mixing, the CNTs were then added for further compounding. It is found that the CNTs are selectively located in the PTT phase and on the phase interface at the middle stage of melt mixing. Those interface-located CNTs can act as additional substrate to catalyze or even participate in the transesterification themselves, finally homogenizing phase morphology of the matrix blend. As a consequence, the degree of randomness of the composite systems increases remarkably accompanied by reduced number-average length of copolymer sequences compared with those of the blend systems merely with Ti(OBu)4. Such a promoting effect, however, is highly dependent on the CNT loadings, and weakened gradually with increasing loadings of CNTs.
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http://onlinelibrary.wiley.com/doi/10.1002/macp.201100095/abstract