Crystallization of synthetic trans-l,4-polyisoprene (TPI) at -20°C in hexane and amylacetate solutions gave chain-folded s-type crystals with 53% and 57% crystallinity, respectively. Selective ozonolysis degradation of the isoprene units in the surface folds associated with high-resolution g.p.c, measurement was used to determine the crystalline stem length, stem length distribution and fold surface structure of the ~-TPI crystals. As ozone uptake increased, the isoprene units of the main fraction of oligomer products were found to decrease from 13, reaching a constant value at 11 for hexane and 12 for amylacetate. The polydispersity of the oligomer fractions was found to be in the range of 1.01-1.02. These findings suggested that the chain fold structure might be tight folding with slightly irregular folds, with a stem length of 11 monomers and a dispersion of 2.3 for lamellae grown from hexane, and 12 monomers with dispersion of 2.3 for those grown from amylacetate.
Посилання на статтю:
Structure of solution-grown trans-l,4- polyisoprene crystals: 1. Determination of stem length and fold surface structure by ozonolysis-g.p.c, measurement / Ploenpit Boochathum*, Mikio Shimizu, Katsumi Mita and YasuyukiTanaka // Polymer. – 1993. – Vol 34. – P. 2564-2568.