Haupt‐ und seitenkettenkristallinität bei isotaktischen poly(1‐alkylethylen)en, 2. Röntgenographische, kalorimetrische und ramanspektroskopische untersuchungen am it‐poly(1‐eicosylethylen)

Abstract

Isotactic poly(1 -eicosylethylene) shows three polymorphic modifications. The orthorhombic modification I is formed during melt crystallization at a cooling rate 4<2,5K.s-'. The dimensions of the unit cell are calculated to be a = 0,75 nm, b = 8,s nm and c =0,67 nm. The heat of fusion is 145 J . g-', the melting point is 363 K. The monoclinic modification I1 is crystallized from the polymer solution (a=0,53nm, b=10,8nm, c=0,77nm, /3=94"). The heat of fusion amounts to 120J.g-', the melting point is 356 K. Modification 111 is formed during rapid quenching of the melt. The side-chains crystallized closely packed in layers. Modification 111 shows no main-chain crystallinity. The heat of fusion is 40 J . g-I, the melting point is 348 K. The crystal field splitting in the Raman spectrum of modification

Influence of a functional group situated along the side chain on side chain crystallinity and on the heat and entropy of melting of comblike poly[N-(n-alkyl(oxycarbonyl)methyl)maleimides] and poly[N-(5-(n-alkyl(oxycarbonyl))-n-pentyl)maleimides]

“…A second procedure is based on the assumption that a plot of AHf vs. n gives a straight line as shown in Figure 5. When AH{ = 0, i.e., AH¡ = C + k'n = 0, the number of crystalline and amorphous methylenes groups are respectively n'a = C/k' (7) n'c = -n'a (8) and the degree of crystallinity X'c = 14.026 (nn'a)/MW(structural unit) (9) Values calculated according to this second procedure are also gathered in Table IV and as can be seen are practically identical with those calculated by the first approach. The values obtained by these two procedures will yield the same value for the crystalline fraction.…”