The action of chain extenders in nylon-6, PET, and model compounds

Abstract

ABSTRACT:The action of two complementary chain extenders is studied in model systems as well as in poly (ethylene terephthalate) (PET ) and nylon-6. Chain extenders are low molecular weight compounds that can be used to increase the molecular weight of polymers in a short time. The reaction must preferably be fast enough to execute this step in an extruder. 1,3-Phenylene bis(2-oxazoline-2) (PBO ) and isophthaloyl biscaprolactamate (IBC ) are used in this study. Bisoxazolines react quickly with carboxylic acids. With model compounds it is shown that, under processing conditions, high conversions can be reached. However, the conversion is not complete. The high rate and the absence of volatile reactants are the most important characteristics of this reaction. Bislactamates are suitable coupling agents for hydroxy and amino functional polymers. The path of this coupling reaction depends on the type of nucleophile and on the reaction temperature. Under mild conditions the elimination of caprolactam is the main reaction. Under more severe conditions the ring opening mechanism may also be operative. The increase of the viscosity is studied with one as well as with a mixture of the two chain extenders. The effect is larger when both types of chain extenders are used simultaneously.

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

“…Hydroxy and amino groups rather react with bis-2-oxazinones or bislactamates. In the case of polymers containing different reactive groups, a combination of coupling agents was applied [15].…”

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.…”

“…[18,19] In the case of polymers that contain different reactive groups, a combination of coupling agents has been applied. [15] Diisocyanates and bisoxazolines have been used as chain extenders for liquid-crystalline poly(ethylene terephthalateco-oxybenzoate)s under the conditions of reactive processing. [20] The literature provides a number of examples where coupling agents have been used for the preparation of polyamide/polyester block copolymers.…”

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

“…[1][2][3] In the chain extension of polyesters, different chain extenders have been used with polyesters with different terminal groups. Chain extenders such as bisoxazolines, 4 bisaziridines, and diepoxides 5 have usually been used in the chain extension of HOOC-terminated polyesters; others such as diisocyanate, 6 tetracarboxylic dianhydride, 7 carbonyl biscaprolactam, 8 1,3-isophthaloyl biscaprolactamate, 9 and terephthaloyl biscaprolactamate 10-12 and octamethylcyclotetrasilazane or hexaphenylcyclotrisilazane 13 have been used in the chain extension of HOterminated polyesters.…”