Question

Case study [eta]M_n = 2.5N_AV_h The intrinsic viscosity of polymer solution follows Mark-Houwink-Sakurada relation: $[eta] = KM^alpha$. For polystyrene (PS) in tetrahydrofuran, $K_{PS} = 3.71 imes 10^{-4} dl/g$ and $alpha_{PS} = 0.64$. For poly(methyl methacrylate) (PMMA) in tetrahydrofuran, $K_{PMMA} = 4.18 imes 10^{-5} dl/g$ and $alpha_{PMMA} = 0.83$. (1) What is the hydrodynamic volume of PS and PMMA with molecular weight of 1,000,000 g/mol? (Note that $dl = 10^{-4} m^3$) (2) A SEC has been calibrated by PS standards and find out the relationship between the hydrodynamic volume ($V_h$) and the elution volume ($V_R$(mL)) following: $log(2.5N_AV_h) = 21.72 - 1.5578 imes V_R + 0.06325 imes V_R^2 - 0.00102 imes V_R^3$. A monodisperse PMMA with unknown molecular weight has an elution volume of $V_R =$ 29.3 mL, please identify the molecular weight of this PMMA.

          Case study
[eta]M_n = 2.5N_AV_h
The intrinsic viscosity of polymer solution follows Mark-Houwink-Sakurada relation: $[eta] = KM^alpha$. For polystyrene (PS) in tetrahydrofuran, $K_{PS} = 3.71 	imes 10^{-4} dl/g$ and $alpha_{PS} = 0.64$.
For poly(methyl methacrylate) (PMMA) in tetrahydrofuran, $K_{PMMA} = 4.18 	imes 10^{-5} dl/g$
and $alpha_{PMMA} = 0.83$.
(1) What is the hydrodynamic volume of PS and PMMA with molecular weight of
1,000,000 g/mol? (Note that $dl = 10^{-4} m^3$)
(2) A SEC has been calibrated by PS standards and find out the relationship between the
hydrodynamic volume ($V_h$) and the elution volume ($V_R$(mL)) following:
$log(2.5N_AV_h) = 21.72 - 1.5578 	imes V_R + 0.06325 	imes V_R^2 - 0.00102 	imes V_R^3$. A
monodisperse PMMA with unknown molecular weight has an elution volume of $V_R =$
29.3 mL, please identify the molecular weight of this PMMA.

Case study
[eta]Mn = 2.5NAVh
The intrinsic viscosity of polymer solution follows Mark-Houwink-Sakurada relation: [eta] = KM^alpha. For polystyrene (PS) in tetrahydrofuran, KPS = 3.71 imes 10^-4 dl/g and alphaPS = 0.64.
For poly(methyl methacrylate) (PMMA) in tetrahydrofuran, KPMMA = 4.18 imes 10^-5 dl/g
and alphaPMMA = 0.83.
(1) What is the hydrodynamic volume of PS and PMMA with molecular weight of
1,000,000 g/mol? (Note that dl = 10^-4 m^3)
(2) A SEC has been calibrated by PS standards and find out the relationship between the
hydrodynamic volume (Vh) and the elution volume (VR(mL)) following:
log(2.5NAVh) = 21.72 - 1.5578 imes VR + 0.06325 imes VR^2 - 0.00102 imes VR^3. A
monodisperse PMMA with unknown molecular weight has an elution volume of VR =
29.3 mL, please identify the molecular weight of this PMMA.

Added by Sheena H.

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