Please describe in terms of mo
Please describe in terms of molecular motion and inter-chainattractive forces, the motion of polymer chains of a viscouspolymer film as it is cooled at a constant rate as the sample movesthrough three temperature regimes:
a. Above Tg
b. Near or at Tg
c. Below Tg
Answer:
In terms of molecular motion and inter-chain attractiveforces, the motion of polymer chains of a viscous polymer film asit is cooled at a constant rate as the sample moves through threetemperature regimes:
a) At temperatures above glass transition temperature(Tg) (how much the temperature exceeds the Tg) – a non-crystalline polymer material behaves like a viscous fluidor like a rubbery , depending on the molecular weight . AboveTg molecular motion or transition and inter-chainattractive forces will takes place as free volume increases thus ,the motion of polymer chains of a viscous polymer film willoccur.
b) Near or at Tg – At this point polymerexperience transition from glassy state to rubbery state, Loss ofmodulus (or stiffness) occur and also significant loss of volumetake place. Near or At glass transition temperaturetransition molecular motion and inter-chain attractiveforces will remain constant as free volume does notchange.
c) Below Tg (how much it is cooled down), abulk polymer which is described as a glass and it is less or morebrittle depending on the structural complexity (and the remainingflexibility might be provided by side-chains) and also reduce infree volume does not allow molecular motion or transition to takesplace.
"Our Prices Start at $11.99. As Our First Client, Use Coupon Code GET15 to claim 15% Discount This Month!!"
