Why do iPP and PET show different behavior in phase transitions when they are he
ID: 1060605 • Letter: W
Question
Why do iPP and PET show different behavior in phase transitions when they are heating up in the DSC? Relate it to their molecular structure. What degree of crystallinity would you expect for a polypropylene with a degree of tactility between that of iPP and aPP? If a given iPP sample is crystallized at a higher cooling rate that another iPP sample, which one would you expect to have better mechanical properties? Why? does iPP crystallized under quiescent conditions have isotropic or anisotropic properties? What about iPP crystallized after the fiber pull? Explain.Explanation / Answer
1. Polymers PET and iPP behave differently in DSC in terms of phase transitions. PET is more crystalline than PP due to irregularity in structure and thus when heated in DSC they show sharp phase transitions as opposed to semi-cryrtalline or amorphous iPP polymer.
2. The degree of crydtalinity for a polymer which has crystalinity between iPP and aPP would be somewhere mid-rage between the two types of polymers. The structure would be semi-crystalline.
3. iPP with higher cooling rate would have better mechnical properties as it becomes hard when cooled faster.
4. iPP cystalized under quiescent conditions have anisotropic properties. iPP crystallized after fibre pull would have isotrpoic properties
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.