Synthesis of Interpenetrating Polymer Networks Based on Triisocyanate-Terminated and Modified Poly(urethane-imide) with Superior Mechanical Properties

Abstract

Interpenetrating polymer networks (IPNs) based on triisocyanate-terminated poly(urethane-imide)s (PUIs) were prepared by in situ interpenetrating reactions between modified polyurethane (PU) with different ratios of polyimide (PI). The effects of PU, which was made from hydroxyl-terminated polybutadiene modified with triisocyanate, and the amounts of PI on the mechanical properties, thermal properties, and crystalline character of the IPNs were discussed. Triisocyanate-terminated PUI showed that the highest tensile strength was 38 times that of the diisocyanate-terminated materials. Supramolecular cross-linking from an additional hydrogen-bonding network of modified PU and the degree of interpenetration with a regular imide structure of PI were introduced, which accounted for the remarkable improvement in mechanical properties of IPNs. Preferable thermal stability and glass transition temperature for the hard segment of IPNs were rewarded with increasing PI content. X-ray diffraction revealed vigorous segmental mixing between the soft and hard segments of modified PUI. Scanning electron micrographs showed the "fibrous assembly" morphology and short-range-ordered structure of modified PUI.

Interpenetrating polymer networks of polyurethane and polytriazole: Effect of the composition and number average molecular weight of glycidyl azide polymer on the mechanical properties and morphology

“…That is to say, the result demonstrated the presence of additional physical crosslinks and entanglement for full‐IPNs. The degree of molecular interpenetration accounted for the remarkable improvement in mechanical properties of IPNs 11 . However, when the M n of GAP was 1 k, this phenomenon did not exist.…”

“…Another convenient and effective way is to prepare interpenetrating polymer networks (IPNs), which is a chemical blending technology that can be defined as permanent entanglements of two or more crosslinked polymers in the form of networks with excellent physico-mechanical properties. [1][2][3][4][5] In other nonpropellant research areas, the mechanisms on how the IPN to improve the mechanical properties have been well studied, [6][7][8][9][10][11][12][13] which have been clarified that the interpenetration degree between the two phases of IPNs and microphase separation accounted for the remarkable improvement in mechanical properties of IPNs through distinctive network interpenetrating structure, forced compatibility between two phases, interpenetrating interfaces and synergistic effect. [14][15][16] GAP was widely developed because of its high positive heat of formation, high density, and good compatibility with advanced oxidizers.…”

A survey of recent publications on polymers employing reactive, halogen‐free flame‐retardant functionalities

“…Poly(imide-urethane) copolymers have grown more prevalent in recent literature, 21,22 although less research has characterized their flame-retardant characteristics. Tang et al 23 described a series of thermoplastic (polyimide-urethane)s (TPIUs) with inherently flameretardant properties.…”

“…Poly(imide‐urethane) copolymers have grown more prevalent in recent literature, 21,22 although less research has characterized their flame‐retardant characteristics. Tang et al 23 .…”