Crystallization of segmented trans-1,4-polyisoprene/epoxidized trans-1,4-polyisoprene block copolymers from solution

The crystallization of segmented block copolymers of trans‐1,4‐polyisoprene (TPI)/expoxidized TPI from solution was investigated. One preparation with an average TPI block length of 14.5 and an average epoxidized TPI block length of 10 was crystallized from 2‐pentanol at 20°C, 2‐octanol at 20°C, and 2‐pentanone at 0°C. A second preparation with an average TPI block length of 18 and the same average epoxidized TPI block length was crystallized from 2‐octanol at 20°C and 2‐pentanone at 0°C. The crystallization products were expoxidized in suspension a second time and then characterized by carbon‐13 solution NMR to determine the average noncrystalline traverse length and the average crystalline stem length. The crystallized products were also studied by scanning electron microscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry to determine the morphology, the crystal form and crystallinity, and the melting point, respectively. The average noncrystalline traverse length was found to be highly dependent on the crystallization conditions and the crystalline stem length of the parent TPI lamellas; the composition of these traverses is discussed.