Question

PET has a Young's, Modulus of 3.5 GPa and PLGA 1.2 GPa. A polymer blend is prepared with 40:60 mixture (PET:PlGA) . What is the Young's, Modulus of this blend (use mixture rule). Calculate the percent load borne by PET when the blend is subjected to a load. If after 10 days, half of PET and one third of PLGA had degraded, what is the Young's Modulus of this blend.

Answer 1

$Young's modulus=Y_{PET}=$ 3.5 GPa, $Y_{GPA}= 1.2 GPa$

It has mixture of 50:50

$Y_m= \frac {2}{5}Y_{PET} + \frac {3}{5}Y_{GPA}$

$Y_m= \frac {3.5\times2}{5} + \frac {3\times 1.2}{5}$

$Y_m= 1.4+ 0.72= 2.12\ GPa$

Let P be the load applied on blend mixture

Total elongation = elongation of 1 + elongation of 2

so here Youngs modulus for mixture after 10 days as per rule of degradation

$Y_m =$ $\frac{3.5}{2} +\frac{1.2}{3}= 1.74 + .4= 2.14$ GPa

This Youngs modulus after 10 days