Correlation of nanostructural parameters and macromechanical behaviour of hyperbranched-modified polypropylene using time-resolved small-angle X-ray scattering measurements

Polypropylene (PP) is modified utilizing a poly(ester amide)-based hyperbranched polymer (PS). A maleic-modified PP is used to enhance the compatibility. Usual tensile experiments are carried out. The nanocrystalline structure is studied using small-angle X-ray scattering (SAXS) while a uniaxial mechanical load is simultaneously applied. SAXS patterns are analysed using procedures written in PV-WAVE. The chord distribution function (CDF) is calculated and nanostructural parameters such as long period (lp) and nanodeformation (ENano) are extracted. The correlations between macromechanical parameters and nanostructures are studied. Mechanical results show that PS has a plasticizing effect. Reactively blended samples demonstrate enhanced mechanical properties. SAXS patterns reveal a well-known structure of PP as a peculiar architecture of the nanostructure. Crystalline branching occurs in a geometry that is known as a mother-daughter crystal lamellar structure, also called a crosshatching structure. It is concluded that adding PS distorts the stacking of crystalline domains. The structural information from SAXS patterns in reciprocal space is visualized in real space in the calculated CDFs. The CDFs indicate that in simple blends, lp of the crystalline stacks increases compared to blank PP. Nevertheless, reactively blended samples show an increase of lp compared to blank PP; however, they possess smaller lp compared to simple blends. (c) 2012 Society of Chemical Industry