Microstructure of two polypropylene homopolymers with improved impact properties

The effect of the mixed external donors on the sequence length distribution of polypropylene

“…There is a good correspondence between the SSA and the TREF techniques 39. The results of SSA are coincident with the results of high‐resolution 13 C‐NMR, TREF, and xylene solvent fractionation, but SSA can provide important quantitative information about the lamellar thickness distribution 29, 32. With the increase of separation temperature, the component separated by TREF shows higher melting temperature and longer crystalline sequence length after SSA treatment.…”

“…SSA technology was designed and first reported by Muller et al30 in 1997, which is based on the self‐nucleation and annealing steps sequentially to a polymer sample originally devised by Fillon et al,31 and has been widely used to analyze the chain structures of semi‐crystallized polymers such as polyethylene and PP 32–44. As SSA can enhance the microstructure fractionation during crystallization and encourage annealing of the unmelted crystals at each stage of the process and the lamellae of crystallization polymer may have enough time to diffuse and grow in the annealing step, the SSA technology can carry on selective thermal fractionation according to the crystallization sequence length of polymer.…”

Study on the sequence length distribution of polypropylene by the successive self-nucleation and annealing (SSA) calorimetric technique

“…However, there is a good correspondence between the SSA and TREF techniques. 11 With the increase of separation temperature, the component separated by TREF shows higher melting temperature and longer crystalline sequence length after SSA treatment. In addition, 13 C NMR result also shows that isotacticity of polypropylene and isotactic sequence length increase.…”

Application of the correct design of successive self-nucleation and annealing (SSA) to study the stereo-defects and its distribution of homo- and co-polypropylene

“…13,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] For PP samples, with the increase of separation temperature, the component separated by TREF showed higher melting temperature and longer isotactic sequence length aer SSA treatment, and 13 C-NMR result also indicated that the isotacticity of polypropylene and isotactic sequence length of PP increased. 27,[35][36][37][38] Compared with 13 C-NMR and TREF fractionation, SSA fractionation was a more time-saving and practical technique in the characterization of the molecular structure of PP, as well as a way providing important quantitative information about the lamellar thickness and its distribution of PP, which gave a more accurate characterization to the isotactic sequence length and its distribution of polypropylene.…”