High-Impact Polyamide Composites with Linear Ethylene-Norbornene Anhydride Copolymers from Insertion Polymerization

Abstract

Toughening of polyamide 66 with novel linear norbornene anhydride functionalized polyethylenes leads to an impact performance in the Charpy- notch impact testing at 23 °C and −30 °C as high as a _CN = 18.0 ± 1.0 and 13.7 ± 0.8 kJ m⁻², respectively, which compares favorably to a state of the art functional low density polyethylene (LDPE) from high-pressure copolymeriza- tion with a Charpy-notch impact strength of a _CN = 16.8 ± 0.0 and 13.8 ± 2.1 kJ m ⁻² at 23 and −30 °C, respectively. The linear copolymers are obtained by insertion polymerization at mild ethylene pressures of 5 to 15 bars with phosphinesulfonato Pd (II) catalysts, to yield linear copolymers with nor- bornene anhydride incorporations as high as 4.8 mol% along with a polymer molecular weight of >10 ⁵ g mol ⁻¹. Furthermore, the norbornene anhydride functionality serves as a reaction site for postpolymerization functionaliza- tion with alcohols to obtain the respective half- and diesters of the anhydride functionality. Notably, the impact performance is improved with the increase of the alkyl chain length and degree of branching of the ester functionality in the order methanol < n-butanol < 2-ethyl hexanol from 10.0 to 13.8 kJ m ⁻².