The non-Newtonian intrinsic viscosities[η] of poly($\gamma$-methyl L-glutamate) were measured in the helixcoil transition region under various conditions in this work. The helix content $f_H$, which represents the degree of conformational transition, was obtained by using a polarimeter. The experimental results show that the non-Newtonian behavior of the polypeptide is markedly affected by its conformation, i.e., the non-Newtonian effect becomes larger as $f_H$ increases. The effect of external pressure Δp on [η] was studied carefully. [η] increases with $f_H$ when Δp<1.5 psi, but it decreases when Δp>1.5 psi and $f_H>0.8$ (Fig. 8). The reason for this result was considered in the text.
In order to find the further evidence for the non-Newtonian flow behavior, the non-Newtonian viscosities of poly (L-proline) were measured in the helix-helix transition region and various salt solutions. The experimental results for poly(L-proline) show that the non-Newtonian behavior is not significantly affected by its $[α]_{D^`}$ which represents the degree of helix-helix transition, while $η _{sp}$/C is remarkably changed by $CaCl_2$ concentrations. These interesting results must be attributed to the unique structure of poly(L-proline), which is studied in this paper.
In Part Two, the experimental data of $[η]^f/[η]^O$ are express by the following equation:
$\frac{[η]^f}{[η]^O} = 1- \frac{A}{[η]^O} [1- \frac{\sinh^{-1} β_2 f/η_0}{β_2 f/η_O} + \frac{1}{kTβ_2} \frac{C_2f}{η_O}] (A1)$ where $[η]^f$ and $[η]^O$ are the intrinsic viscosity at shear stress f and zero, respectively, $A=lim_{c→0} [(1/C)(x_2/β_2)(β_2/η_0)]$, $η_0$= viscosity of the solvent, $β_2$ is the relaxation time of flow unit 2, $C_2$ is a constant related to the orientation effect. The theoretical derivation of Eq.(A1) is given in the text.
The experimental results for poly($\gamma$-methyl L-glutamate) have been shown in the Part One. The experimental curves of $[η]^f/[η]^O$ vs. log f are compared with theoretical curves calculated from Eq.(A1). The experimental curves of $[η]^f$ vs. $f_H$(the helix content in the polymer molecule) at a fixed external pressure are compared with the theoretical predictions with good results.
Next, we further apply the theory to the experimental results of the two systems (organic polymer in various solvents and polypeptides of various chain in helicogenic solvents). The experimental data were analyzed by Eq.(A1), and the experimental curves were compared with theoretical curves with good results.
실험 데이타 $([η]^f/[η]^O)$는 아래 식으로 나타낸다.
$\frac{[η]^f}{[η]^O} = 1- \frac{A}{[η]^O} [1 - \frac{\sinh^{-1} β_2 f/η_O}{β_2f/η_O} + \frac{1}{kTβ_2} \frac{C_2f}{η_O}]$ (A1) $[η]^f$와 $[η]^O$은 각각 가해준 외부 힘이 f 와 o 일때 고유 점성을 나타내며, $A \equir lim_{c→0} [(1/C)(x_2/α_2) (β_2/η_O)]$, $η_O$는 용매 점성, $β_2$는 흐름 단위 (flow unit) 2의 완화 시간 (relaxation time), $C_2$는 배열 효과 (orientation effect)와 관계되는 상수 이다. 식(A1)의 이론적 유도는 본문에 나타냈다.
응용 A에서는, poly($\gamma-$methyl L-glutamate)의 실험 결과에 대하여 적용 했다. 실험 곡선 $([η]^f/[η]^O vs. log f)$은 식(A1)으로부터 계산된 이론적인 곡선과 비교 분석 했다. 그리고 주어진 외부 압력에서 실험 곡선 ([η] vs. $f_H$) 역시 이론 곡선과 일치 했다.
응용 B에서는, 여러가지 용매에서 유기 고분자와 여러가지 사슬 길이에서 생체 고분자의 실험 결과에 적용 해본 결과 실험 곡선과 이론 곡선이 타당했다. 유기와 생체 고분자의 실험 데이타를 이론으로 분석 해본 결과 유기고분자에서는 전혀 배열 효과 (orientation effect)가 나타나지 않았으나, 용매-용질간 친화력 (solvent power)이클수록 비-뉴우톤 효과는 증가 했다. 생체 고분자에서는 사슬 길이가 클수록 배열 효과는 기하 급수적으로 증가 했다. 변형과 배열 효과를 고려한 이론을 실험 데이타에 적용 해본 결과 $β_2$와 $C_2$ 값의 합당한 경향을 얻었으며, 모든 실험치와 잘 일치 했다.
