The outlined polymorph selection of iPB-1 revealing by incorporation of a dentritic polymer

By incorporating a hydrophilic dentritic polyester into polymorphic isotactic polybutene-1 (iPB-1), we successfully decreased its viscosity as designed to trigger the melt crystallisation of form III due to the proposed decrease of the interactions between the iPB-1 chain sequences. In addition to the usual form II formation, the form III formation resulting from cooling the iPB-1 melt at suitable cooling rates has been verified by the DSC, WAXD, and in-situ synchrotron WAXS measurements. It was proposed that the form III melt crystallisation occurs after the 4/1 helix conformation formation in the iPB-1 melt and the following alignment of the resulting 4/1 helices. Once the interactions between the iPB-1 chain sequences are sufficiently strong as in the usual iPB-1 melt, the collapse of the 4/1 into the 11/3 helix conformation would occur and finally trigger the generally observed melt crystallisation of form II. Thus, we first outlined the polymorph selection process of iPB-1 based on the helix conformation formation and the following alignment of the helices which finally result in crystallisation of iPB-1 into corresponding crystal forms. The results are helpful for understanding of both the polymorph selection of polymorphic polymers like iPB-1 and the general polymer crystallisation.