Polymorphic transformation and crystal morphology observation of poly(1-butene)/(1-butene-co-propylene) in-reactor alloy through in-situ FT-IR and POM

Crystallization and polymorphic transformation of poly(1-butene)/(1-butene-co-propylene) in-reactor alloy (iPB/B-co-P) with different chain structure prepared by two stage sequential polymerization was investigated by DSC, FTIR and POM. As can be concluded from DSC results, the crystal form II to I transformation rate is enhanced with the increase of propylene unit content for alloy with the chain structure of isolated propylene unit distribution. However, the alloy which has the chain structure of predominant segmented propylene co-unit distribution, although with the highest propylene unit content and lowestmolecular weight, the crystal form II to I transformation rate still lower than two of the three alloys with isolated propylene unit and lower propylene unit content. This conclusion was also demonstrated by the subsequent in-situ FT-IR characterization. The crystallization process and morphology was investigated through polarized optical microscopy.