Graft interpenetrating polymer networks of polyurethane and epoxy. I. mechanical behavior

Abstract

SUMMARYThe interpenetrating polymer networks (IPNs) prepared from polyurethane (PU) and a glycidyl ether of phenol formaldehyde (GEPF) were synthesized by using a simultaneous polymerization method. The effects of PU molecular weight and amount on the mechanical property are discussed. For the PU/GEPF IPNs based on polyester-type PU, as the PU content was increased, the tensile strength and fracture energy decreased, but the impact strength increased significantly. However, for the PU/GEPF IPNs based on polyether-type PU, the extent of heterogeneity was decreased with decreasing molecular weight of polyether polyol in PU and the tensile strength and fracture energy were enhanced. The impact strength increased to a maximum value and then decreased when the PU content was further increased. ZUSAMMENFASSUNG:Interpenetrierende Netzwerke (IPN) aus Polyurethanen (PU) und dem Glycidylether eines Phenol-Formaldehyd-Kondensates (GEPF) wurden durch gleichzeitige Polymerisation (,,Cokondensation") hergestellt. Der EinfluB des PU-Molekulargewichts und -Gehalts auf die mechanischen Eigenschaften wird diskutiert. Bei PU/GEPF IPN aus Polyester-Typ-PU nahmen mit steigendem PU-Gehalt sowohl die Zugfestigkeit als auch die Bruchenergie ab, wahrend die Schlagfestigkeit signifikant anstieg. Demgegenuber zeigten PU/GEPF IPN aus Polyether-np-PU eine sinkende Heterogenittit mit abnehmendem Molekulargewicht der Polyetherpolyol-Komponente im PU und dementsprechend eine Zunahme sowohl der Zugfestigkeit als auch der Bruchenergie. Die Schlagfestigkeit zeigte dagegen mit steigendem PU-Gehalt zunachst einen Anstieg zu einem Maximalwert, um dann wieder abzufallen.

Preparation and property evaluation of nanocomposites based on polyurethane‐modified epoxy/montmorillonite systems

“…[11][12][13][14][15] Epoxy resin's properties have also been improved by using nanoparticles [16][17][18][19][20] as well as other cross-linkable polymers to form full-or semi-interpenetrating polymer networks. [21][22][23][24][25][26][27][28][29] Yilmazer and co-workers 16 have used unmodified montmorillonite (Cloisite Na + ) and organically modified Cloisite 30B as reinforcing agents for diglycidyl ether of bisphenol-A (DGEBA), Their results have shown an increase in the glass transition temperature (Tg) by more than 10°C with the addition of 9 wt% of a modified montmorillonite (MMT). The addition of 0.5 and 1 wt% of Cloisite 30B resulted in a maximum improvement in the impact strength of DGEBA.…”

“…Polyurethane chains can be linked to the epoxy network through physical entanglements as well as chemical bonding to form graft interpenetrating polymer network (IPN) structures. Hsieh and Han 21 have evaluated the mechanical properties of graft IPN of an epoxy and a PUR based on polyols with different chain lengths. The results showed that the significant improvement in the tensile strength was related to the grafted structure and to the length of PUR chains.…”

The toughness of epoxy-poly(butylene terephthalate) blends

“…In some respects the gelled blends of PBT and epoxy are similar to interpenetrating networks (IPNs) [37][38][39]. Semi-IPNs, in particular, are formed by mixing a monomer with a linear polymer and polymerizing the monomer around the polymer.…”

Investigation of the Compression and Dielectric strength properties for Epoxy/Polyurethane Blends reinforced with glass fibers

“…E-glass (electrical)-lower alkali content and stronger than A glass (alkali). Good tensile and compressive strength and stiffness, good electrical properties and relatively low cost [8][9]. Polymers are basically electrical insulators with low dielectric permittivity and often high dielectric strength.…”