Synthesis and Structure–Efficiency Relations of 1,3,5‐Benzenetrisamides as Nucleating Agents and Clarifiers for Isotactic Poly(propylene)

Abstract

This paper presents the synthesis and properties of 1,3,5‐benzenetrisamides with a particular focus on structure‐efficiency relationships of nucleation and optical property enhancement of isotactic poly(propylene) (i‐PP). A family of twenty 1,3,5‐benzenetrisamide derivatives was synthesized, in which the direction of the amide linkage between the core and the peripheral substituents, as well as their length (C‐3 to C‐6) and flexibility were systematically varied. Dissolution‐ and recrystallization temperatures of the additives in the polymer melt, the crystallization temperature of i‐PP, and the optical properties clarity and haze were determined in the additive concentration range from 200 to 2 500 ppm. Within the reported series of compounds, few exhibited very good nucleating and clarification abilities, only one with outstanding characteristics, whereas other, very closely related derivatives were found to be incapable to nucleate or clarify i‐PP, although, intriguingly, most are structural isomers. We conclude that it is the particular chemical structure of the additive that determines its crystallization/self‐assembly process, and, therewith, the structure of the heterogeneous nuclei, and at a higher hierarchical level the morphology of the poly(propylene) solid state and its final properties; and, hence, that a predictive understanding is still elusive.magnified image

Effect of the Molecular Structure of the Polymer and Nucleation on the Optical Properties of Polypropylene Homo- and Copolymers

“…These latter additives dissolve in the polymer generating a microcrystalline structure and improve haze considerably [10][11] . In the last decade a relatively new family of nucleating agents based on trisamide derivatives appeared as the competitor of sorbitol clarifiers [12][13][14][15] . However, the efficiency of the clarifier depends very much also on the characteristics of the polymer used and on processing conditions, as mentioned above.…”

Improvement of the impact strength of ethylene‐propylene random copolymers by nucleation

“…1, the relationship is the same when the trisamide compound is used, only the concentration range is different, because of its smaller critical concentration. According to earlier studies sorbitol derivatives act only above 1500 ppm 36 , while trisamide based nucleating agents are already active above 100-300 ppm 31 . It is interesting to note that the effect of solubility is smaller, but the efficiency of nucleation is larger in the copolymers containing more ethylene than for those with small comonomer content.…”

A New Class of Ultra‐Efficient Supramolecular Nucleating Agents for Isotactic Polypropylene

“…[ 21 ] In contradiction to solvent used by him, which has to be removed by extraction, HMN can be completely removed under vacuum at room temperature. crystallization temperatures ( T c,p ) of previously published [ 17 ] i -PP compounds at the same concentration with analogues additives without the trimethyl substitution at the core can be made. For instance, additive 1 (R: i -propyl) exhibits a T c,p of 128.2 ° C, whereas for the same R without the trimethyl substitution at the core, a much lower T c,p of 117.5 ° C was observed.…”