Supplementary Materials

Insulative ethylene-propylene copolymer-nanostructured polypropylene for high-

voltage cable insulation applications

Seunggun Yu*,†, Seong Hwan Lee†, Jin Ah Han, Myung Sang Ahn, Hoyyul Park, Se Won

Han*, Dae Ho Lee*

Insulation Materials Research Center, Korea Electrotechnology Research Institute (KERI),

Gyeongsangnam-do 51543, Korea

*Corresponding author(s): S.Yu (viola@keri.re.kr), S.W.Han (swhan@keri.re.kr), D.H.Lee

(neokatari@keri.re.kr)

†These authors equally contributed to the paper.

Supplementary Materials

Table S1. Materials and Characteristics

PP EOC rPP

Supplier SK Chemical LG Chemical SK Chemical

Grade H350F LC170 R362Y

Melt flow index (g/10 min) 7.0 1.1 14.0

Softening temperature (oC) 154.0 - 135.0

Hardness (Shore A) 95.0 9.5 28.0

Contact angle in water (o) 94.7 ± 1.0 103.4 ± 1.5 100.1 ± 0.9

Contact angle in DIM (o) 49.0 ± 0.9 60.5 ± 1.1 52.3 ± 0.8

Surface energy (mJ/m2) 34.7 ± 0.4 28.1 ± 0.6 32.7 ± 0.5

Supplementary Materials

Figure S1. Optical microscopic images observing contact angle of water onto (a) PP, (b)

EOC, and (c) rPP, and DIM onto (d) PP, (e) EOC, and (f) rPP, respectively.

Supplementary Materials

Figure S2. SEM images of PP blends with EOC of (a,d) 10 wt%, (b,e) 20 wt%, and (c,f) 30 wt%, respectively.

Supplementary Materials

Figure S3. Illustrated images of (a) rPP0, (b,e) rPP25, (c,f) rPP50, and (d,g) rPP75, respectively, which are extracted by ImageJ program.

Supplementary Materials

Figure S4. XRD graphs of rPP, rPP25, rPP50, rPP75, and rPP100, respectively.