Crystallization Kinetics of PE-b-isotactic PMMA Diblock Copolymer Synthesized Using SiMe2(Ind)2ZrMe2 and MAO Cocatalyst

Polyethylene-b-poly(methyl methacrylate) (PE-b-PMMA) diblock copolymer has important interfacial applications. Hence, a PE-b-isotactic PMMA diblock copolymer was synthesized using SiMe2(Ind)(2)ZrMe2 and MAO cocatalyst. The polymerization mechanism and the origin of PMMA isotacticity were duly explained. An appropriate nonisothermal Avrami-Erofeev crystallization model was developed to compare the crystallization kinetics of the above copolymer with that of a PE homopolymer. For both polymers, the model well matched the entire differential scanning calorimeter crystallinity profile, notably for a single Avrami-Erofeev index, and predicted cylindrical crystal growth. This model particularly overcomes the limitations of the published nonisothermal crystallization models, and provides interesting insight into PE crystallization. The PMMA block significantly decreased the heats of crystallization and fusion, % crystallinity, and the relative crystallization function; increased the nonisothermal crystallization rate constant; and introduced minimal dilution effect whereas the PE block formed a continuous or percolated phase. This study correlates catalyst structure, copolymer block tacticity, and PE nonisothermal crystallization and melting behavior. (C) 2012 American Institute of Chemical Engineers AIChE J, 59: 200-214, 2013