Effect of magnesium malonate on the formation of the β crystalline form in isotactic polypropylene

Abstract

Magnesium malonate (MgMt) is used to induce the b crystalline form in isotactic polypropylene (iPP) for the first time. It is shown by wide angle X-ray diffraction, differential scanning calorimetry, and polarized light microscopy that the content of the b crystalline form increases markedly with the addition of MgMt and attains the maximum value at an MgMt content of 0.10 wt%. The tensile strength and flexural modulus of the doped iPP sample decrease somewhat; the tensile strain at break increases slightly; and the Izod notched impact strength increases significantly with the addition of MgMt, as compared with the values for the blank iPP sample. The b-nucleation mechanism of MgMt is analyzed by the dimensional lattice match criterion.

Crystal structure and melting behavior of homo-polypropylene and heterophasic ethylene–propylene copolymer after long time heat treatment

“…Among all these crystal phases, a form is the most stable and common one. Generally, pure iPP tends to crystallize mainly into a phase, and other forms will transform into it in certain conditions [9]. However, b-iPP has more advantages in comparison with the traditional a-iPP, for instance, better elongation at break, lower density, more transparency, higher impact strength, tearing strength, etc.…”

Crystallization of isotactic polypropylene in the presence of a β‐nucleating agent based on a trisamide of trimesic acid

“…To trigger the formation of β‐iPP, one can use derivatives of terephthalamide,14, 15 glutaramide,16 succinamide,17 and adipamide18 as well. Recently, Dou and Lu19–21 have found that some metallic salts of malonic acid possess β‐nucleating ability. Some complexes of rare earth metal (denoted as WBG) can also induce the formation of the β‐form 22–24.…”

Effects of analcime zeolite synthesized from local pottery stone as nucleating agent on crystallization behaviors and mechanical properties of isotactic polypropylene

“…. Five distinct α‐peaks at 2 θ of 14°, 16.9°, 18.8°, 21°, and 21.8° corresponding to (110), (040), (130), (111), and (131) lattice planes, respectively, were observed in all the iPP samples. These characteristic peaks were assigned to the α‐monoclinic iPP crystal.…”

“…As the spherulite size is relatively large (greater than 10 µm), the presence of voids at the spherulite boundaries caused by contraction of the spherulite on cooling leads to a reduction in the impact resistance of the specimens . An interesting characteristic of iPP is its polymorphism, as it can crystallize into several crystalline forms: α, β, and γ . The monoclinic α‐iPP is the most common crystalline state and the most stable thermodynamically under the normal processing conditions; whereas the hexagonal β‐iPP and the orthorhombic γ‐iPP can be obtained only under the particular conditions .…”