Polyamide–polyester multiblock copolymers by chain‐coupling reactions of carboxy‐terminated polymers with phenylene and pyridylene bisoxazolines

Abstract

Polyamide-polyester multiblock copolymers were synthesized through the reaction of ␣,-dicarboxy polyamides and polyesters with various arylene bis(2-oxazoline)s. 2,2Ј-(2,6-Pyridylene)bis(2-oxazoline) was very reactive and yielded multiblock copolymers with number-average molar masses ranging from 15,000 to 25,000 after 30 min of reaction in the bulk at 200°C. The molar masses and thermal properties of the resulting random multiblock copolymers (glass-transition temperature, melting temperature, and melting enthalpy) were close to those of their alternating homologues prepared by conventional polycondensation between diamino polyamides and dicarboxy polyesters. This showed that the presence of coupling agent moieties in the polymer chains did not exert a significant influence on the block copolymer morphology. The chain-coupling method showed several advantages over conventional polycondensation: a much shorter reaction time, a lower temperature, no byproducts, and easy control of the final copolymer properties through the mass ratio of the starting oligomers.

Multifunctional coupling agents. Part 4: Block copolymers based on amino terminated polyamide-12 and carboxy terminated poly(butylene terephthalate)

“…To promote coupling reactions between the components of polyamide/polyester laminates bisoxazoline derivatives were used [6]. Nery et al [18] describe the preparation of statistical multi-block copolymers based on dicarboxy terminated polyamides and polyesters by using various arylene bisoxazolines. The highest reactivity was observed when 2,2 0 -(2,6-pyridylene)bis(2-oxazoline) was used as coupling agent.…”

Introduction of a New Coupling Agent for Selective Coupling of Hydroxy and Amino Group‐Containing Polymers

“…In the literature, numerous examples are given that describe the utilization of reactive bifunctional compounds as chain extenders and coupling agents, such as diisocyanates, [1][2][3] bisoxazolines, [4][5][6][7][8][9][10] bisepoxides, [11][12][13][14] bislactamates, [15][16][17] and bisoxazolones. [18,19] In the case of polymers that contain different reactive groups, a combination of coupling agents has been applied.…”

“…Here, the highest reactivity was observed when 2,2 0 -(2,6-pyridylene)bis(2-oxazoline) was used as coupling agent. [4] Copolyamide/ polycaprolactone-diol (PCL) multiblock copolymers were synthesized by coupling amino-terminated polyamides and PCL diols with hexamethylene diisocyanate in dimethylformamide. The thermo-mechanical properties of these polymers including shape memory effects were studied [21] For the preparation of segmented block copolymers, common coupling agents as described above can only be used if the starting blocks possess terminal groups of similar reactivity.…”

Catalyzed chain extension of poly(butylene adipate) and poly(butylene succinate) with 2,2′‐(1,4‐phenylene)‐bis(2‐oxazoline)

“…They have often been used to enhance the molecular weight of poly(ethylene terephthalate) (PET) and polyamides during melt polycondensation. 1,[14][15][16] Tuominen and Seppala 17 studied the chain extension of poly(lactic acid) with bis(2-oxazoline). Serious racemization during the melt polycondensation and chain extension resulted in an amorphous poly(lactic acid), although L-lactic acid was used as a starting material.…”