A novel effective way of comprising a β-nucleating agent in isotactic polypropylene (i-PP): Polymerized dispersion and polymer characterization

A kind of beta-nucleating agent, namely a stearic acid and stearate lanthanum complex (NA beta), was introduced into isotactic polypropylene (i-PP) via an in situ polymerization method for the first time. A dynamic adhesion model was constructed for interpreting the beta-nucleating agent dispersion process. The effects of a polymerized dispersion of the beta-nucleating agent on the content of beta-crystal and crystallization behavior of i-PP were investigated. The results show that the crystallization peak temperature of thus beta-nucleated i-PP was greatly increased while the spherulite size dramatically decreased compared with those of net i-PR The content of beta-phase (k(beta) value) can reach as high as 88.7% with only 0.135 wt% of NA beta addition, which holds constant with a further increase of NA beta concentration up to 3.41 wt%. The non-isothermal crystallization kinetics of thus beta-nucleated i-PP was studied with Mo equation and crystallization activation energy estimated by Kissinger method, giving unique results pertaining to the unprecedented NAP polymerized dispersion. (C) 2008 Elsevier Ltd. All rights reserved.