Effects of flexibility and polydispersity onthe dynamical properties of rod-like polymers = 유연성과 분자량 분포가 막대형 고분자의 동력학적 성질에 미치는 영향

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Rod-like polymer molecules have become interesting and important materials because of their good physical and mechanical properties. However, there is notmuch information on the behavior of these materials in solution. Recently a molecular theory presented by Doi and Edwards describes the dynamical and rheological behavior of the solution of rigid rods qualitatively, but large deviation is observed in magnitude of the parameters such as rotational diffusion coefficient from the experimental data. The suggested model considers the chain flexibility and constraint for the motion of the test rod and, it is applied to the monodisperse system at first. If chain flexibility and polydispersity are considered, the discrepancy will be reduced. A new model called a confined stiff chain model is suggested to reduce the deviation. Theoretical prediction for rotational diffusion coefficient ($D_r$) and zero-shear viscosity ($\eta_0$) is in plausible agreement with the experimental data. From the new model length dependence on $D_r$ turns out to be proportional to $L^{-7}$, and constraint on test rod is not severe and disengagement time is much shorter than that of tube model of Doi-Edwards. Concentration dependence on $D_r$ and $\eta_0$ is nearly $c^{-2}$ and $c^{-3}$, respectively. For the precise quantitative analysis of $\eta_0$, it is needed to introduce the correction factor of order L/$\lambda$. Finally, this model is extended to multicomponent system to observe the effect of molecular weight distribution (MWD). Because $M_w/M_n$ and its distribution function are not known, in this study plausible value of MWD and its distribution function are used. The used MWD is in agreement with the values of molecules which are polymerized by ionic method and their dispersities are very narrow. From this fact, this model can be used for the prediction of parameters if MWD and its distribution function is known. MWD does not change the qualitative features which are predicted for ...
Chung, In-Jae정인재
Description
한국과학기술원 : 화학공학과,
Publisher
한국과학기술원
Issue Date
1989
Identifier
61327/325007 / 000835368
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학공학과, 1989.2, [ xi, 128 p. ]

URI
http://hdl.handle.net/10203/29204