EMA3000 Exam 3 Review

What type of chain motion is this depicting?

What type of chain motion is this depicting?

What type of chain motion is this depicting?

What type of chain motion is this depicting?

What kind of motion will occur given the following:

• Translational

• Long
  Cooperative

• Short
  Cooperative

• Vibrational

What kind of motion will occur given the following:

• Translational

• Long
  Cooperative

• Short
  Cooperative

• Vibrational

Where does spider silk gets its variable strength? How does it compare to other sources of silk?

Answer explanation

Silk from spiders is much stronger than from silkworms. Spider silk has large and small beta-sheets.

Calculate the unit cell density of Polyethylene (PE) in g/cm3 to two decimal places.

Better packing favors:
• __?__ percentage of crystalline phase
• __?__ Tm and Tg

• Higher, Higher

• Higher, Lower

• Lower, Higher

• Lower, Lower

Crystallites are typically __?__-__?__ nm, which is only a fraction of the length of a fully extended polymer molecule.