Premium
Crystallization of isotactic polypropylene in the presence of a β‐nucleating agent based on a trisamide of trimesic acid
Author(s) -
Varga József,
Stoll Klaus,
Menyhárd Alfréd,
Horváth Zsuzsanna
Publication year - 2011
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.33685
Subject(s) - crystallization , nucleation , materials science , tacticity , isothermal process , crystallite , chemical engineering , phase (matter) , polymer chemistry , crystallography , thermodynamics , composite material , chemistry , polymerization , organic chemistry , polymer , metallurgy , physics , engineering
Tris‐2,3‐dimethyl‐hexylamide of trimesic acid (TATA) is an new type of β‐nucleating agent for isotactic polypropylene (iPP). The crystallization, melting characteristics, and the supermolecular structure of iPP nucleated with TATA were studied on the samples crystallized under nonisothermal and isothermal conditions. The β‐nucleating ability of TATA was rather high even at low concentration. It was established that TATA possessed dual nucleating ability generating samples with mixed (α and β) polymorphic compositions. The β‐content showed an maximum value at low concentrations (10–100 ppm) of TATA. The β‐content decreased with increasing concentration of TATA in the higher concentration range. The highest β‐content (about 80%) was achieved at the crystallization temperature T c = 110–120°C at low concentration of TATA. The crystallization curves registered at constant cooling rate or under isothermal condition have a single peak in spite of the formation of two polymorphic modifications. The crystallization isotherms cannot be linearized according to the Avrami equation because of simultaneous crystallization of the α‐and β‐forms, having different nucleation and growth rate. It was also found that the β‐content increased with increasing conversion during isothermal crystallization because of the higher growth rate of the β‐phase. The β‐phase formed in the presence of TATA consist of lamellar crystallites. In the early stage of the crystallization, hedritic structure is formed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011