Mechanical properties and morphology of poly(ethylene glycol)‐side‐chain‐modified bismaleimide polymer

Abstract

Two maleimido-end-capped poly(ethylene glycol) (m-PEG)-modified bismaleimide (BMI) resins [4,4Ј-bismaleimido diphenylmethane (BDM)] were synthesized from poly(ethylene glycol) (PEG) of two different molecular weights. A series of m-PEGs and unmodified BDM were blended and thermally cured. The effect of incorporating m-PEG side chains on the morphology and mechanical behaviors of BMI polymer were evaluated. The mechanical properties of these m-PEG-modified BMIs that were evaluated included flexural modulus, flexural strength, strain at break, fracture toughness, and fracture energy. The morphology of these blends was studied with scanning electron microscopy. All the m-PEG-modified BMI polymers showed various degrees of phase separation depending on the molecular weights and concentrations of the m-PEG used. The effects of these morphological changes in the m-PEG-modified BMI polymers were reflected by the improved fracture toughness and strain at break. However, there was a reduction in the flexural moduli in all m-PEG-modified BMI polymers.

Preparation and properties of maleimide‐functionalized hyperbranched polysiloxane and its hybrids based on cyanate ester resin

“…It is known that high curing temperature not only causes high energy consumption, but also results in bigger internal stress and defects of the cured resin, and thereby declines the overall integrated properties of the resultant materials as well as applications, especially those with harsh requirements of outstanding overall properties 6. Generally, adding catalysts is a common method to improve the curing characteristics,7–13 while toughening is usually achieved by copolymerizing with other thermosetting resins, blending with engineering thermoplastics or rubbers, or introducing inorganic fillers 14–17. Each technique has made great progress; however, it is a common phenomenon that the addition of catalyst tends to enhance the brittleness 18.…”