Strutture and crystallization kinetics of poly(L-lactic acid)

A structural investigation is described of poly(L-lactic acid) by best fitting of powder X-ray diffraction patterns. The examined sample shows the already known pseudo-orthorhombic \u3b1-form, and it was possible to determine the location of the two 10 3 polymeric helices in the unit cell and the size distribution of the crystallites. Furthermore, a study is reported of the crystallization kinetics of the above cited polymer by light depolarization measurements in an optical microscope. The crystallization kinetic constants in bulk were evaluated in a temperature range (70\u2013165\ub0C) wider than that previously resulting from measurements of radial growth of spherulites