Synthesis of novel polyimides from dianhydrides with flexible side chains - Polyimides and Other High Temperature Polymers - page 84

Figure 11. X-ray diffractograms of C 8 -FDA at various temperatures (scan rate: 20°C/min).

(Wande Co., Dallas, TX) equipped with a roller covered by a rayon cloth (Yoshi-
kawa Co., Okayama, Japan; YA-20-R). The rubbing density (L/l) was calculated
according to equation (1):

L π rn

2

N

= −

(1)

1

l ν

60

where L (mm) is the total length of the rubbing cloth that contacts a fixed point of
the polymer film, l (mm) is the contact length of the circumference of rubbing
roller, N is the cumulative number of rubbings, n (rpm) is the speed of rubbing
roller, r (cm) is the radius of roller, and

ν (cm/s) is the velocity of the substrate

stage.