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Acetals as nucleating agents for polypropylene
Author(s) -
Smith Tammy L.,
Masilamani Divakaran,
Bui Long Kim,
Brambilla Raymond,
Khanna Yash P.,
Garbriel Kristina A.
Publication year - 1994
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.1994.070520502
Subject(s) - diastereomer , sorbitol , polypropylene , xylitol , ultimate tensile strength , crystallization , crystallinity , nucleation , chemistry , polymer chemistry , polymer , materials science , organic chemistry , composite material , fermentation
Nucleating agents increase the impact strength, tensile strength, and tensile elasticity modulus of semicrystalline polymers. Nucleating agents also decrease product cycle times, resulting in a cost savings per product unit. We have synthesized and tested 15 compounds as nucleactors for polypropylene. Of these, trinapthylidene sorbitol, tri‐(4‐methyl‐1‐naphthylidene)sorbitol, tri‐(4‐methoxy‐1‐naphthylidene) sorbitol, and dibenzylidene xylitol are efficient nucleators of polypropylene. Trinaphthylidene sorbitol (tns) has two major diastereomers: The “ S ” diastereomer yields a faster crystallization rate for polypropylene than does the commercial nucleator dibenzylidene sorbitol (Millad 3905). Crystallization rates are 208 and 88, respectively ( t −1 .05min −1 × 1000). The “ R ” diastereomer, however, is a poor nucleator and interferes with the nucleating activity of the “ S ” diastereomer. A 52/48 mixture of diastereomers does not nucleate polypropylene, even at twice the concentration. This is first time that the importance of stereochemistry has been demonstrated in the nucleating action. © 1994 John Wiley & Sons, Inc.