Crystallization Kinetics of Isotactic Polypropylene Nucleated with Organic Dicarboxylic Acid Salts

Bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate salts (BCHED) were synthesized by hydrothermal method. The crystallization kinetics of isotactic polypropylene (iPP) and nucleated iPP with BCHED were investigated by differential scanning calorimeter (DSC) under isothermal and nonisothermal conditions. Isothermal crystallization kinetics was described by Avrami equation and the fold surface free energy (sigma(e)) of iPP was calculated by Hoffman theory. The results showed Avrami exponents of nucleated iPP become smaller, the values of t(1/2) dramatically decrease, the crystallization rate constants Z(T) greatly increase and the fold surface free energy (sigma(e)) of iPP decrease with the addition of the nucleating agents. Under nonisothermal condition the Caze method was applied to deal with the crystallization kinetics of iPP and the crystallization active energy of iPP was determined by Kissinger method. The results showed the crystallization peak temperatures (T-cp) of nucleated iPP greatly increase, but Avrami exponents of iPP were slightly influenced and the crystallization active energy of iPP increases by the addition of BCHED. It can be concluded that BCHED act as nucleating agents and BCHE11 shows the best nucleating effect. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 1471-1480, 2009