Polyurethane‐modified epoxy resin: Solventless preparation and properties

Abstract

A polyurethane-modified epoxy resin system with potential as an underfill material in electronic packaging and its preparation procedure were studied. The procedure enabled the practical incorporation of an aliphatic polyurethane precursor, synthesized from poly(ethylene glycol) and hexamethylene diisocyanate without a solvent, as a precrosslinking agent into a conventional epoxy resin. With a stoichiometric quantity of the polyurethane precursor added to the epoxy (ca. 5 phr), the polyurethane-modified epoxy resin, mixed with methylene dianiline, exhibited a 36% reduction in the contact angle with the epoxy-amine surface, a 31% reduction in the cure onset temperature versus the control epoxy system, and a viscosity within the processable range. The resultant amine-cured thermosets, meanwhile, exhibited enhanced thermal stability, flexural strength, storage modulus, and adhesion strength at the expense of a 5% increase in the coefficient of thermal expansion. Exceeding the stoichiometric quantity of the polyurethane precursor, however, reduced the thermal stability and modulus but further increased the coefficient of thermal expansion.

An efficient fully bio‐based reactive diluent for epoxy thermosets: 2‐[(Oxiran‐2‐ylmethoxy) methyl] furan versus a petroleum‐based counterpart

“…Epoxy resins are used as matrices for high performance composites, surface coatings, adhesive joints, and so forth, because of low cost, outstanding properties such as thermostability and chemical resistance. However, high viscosity and poor processability of some of common commercial epoxy resins severely restrict the widespread fields of application.…”

The Properties of Regenerative Polymer Mass

“…These masses are often manufactured as two-component materials consisting of an adhesive substance (base) and a curing agent [3,13,17]. After mixing, the two components have a form of dense mass; the mixture can also be liquid, albeit rarely.…”

“…Some adhesive materials require elevated temperatures to cure [3,4,5,12]. The base is primarily made of various epoxy resin compounds [3,7,13]. To improve their mechanical properties, various fillers are additionally used, e.g.…”

Graft‐interpenetrating polymer networks of epoxy with polyurethanes derived from poly(ethyleneterephthalate) waste

“…In this context, blending of epoxy with elastomeric polyurethanes has been attempted to improve the fracture toughness of the base brittle thermoset . Epoxy‐polyurethane blends offer interesting properties, as polyurethanes are associated with excellent elasticity, abrasion resistance, and damping properties, while the epoxy resins possess excellent mechanical properties along with strong adhesion to metals.…”

“…Polyurethanes are particularly attractive elastomers for toughening purpose, because of the possibility of tailoring its mechanical properties by altering the chemical structure . Several attempts in this direction have been made where the polyurethane is derived from poly(oxyethylene), poly(oxytetramethylene), poly(caprolactone), poly(oxypropylene), castor oil, and polyester polyols . However, the potential of PET glycolysate‐based polyurethane has not yet been explored.…”