Thermosetting Resins Based on a Self-Crosslinkable Monomer/Polymer Possessing Meldrum's Acid Groups

Abstract

Thermosetting resins based on Meldrum's acid (MA) derivatives as monomers show high thermal stability and inherent low‐dielectric constants. In this work, a multifunctional MA derivative (MA‐bisF) possessing two MA and two furan groups is newly prepared. Characterization of MA‐bisF has been carried out with Fourier transform infrared, 1H NMR, mass spectroscopy, and elemental analysis. Self‐crosslinking MA‐bisF results in the corresponding thermosetting resin mediating the addition reaction between ketene/ketene and ketene/furan groups. MA‐bisF is also utilized as a modifier for bismaleimide (BMI) resins through polymerizing MA‐bisF and BMI through Diels–Alder reaction. The corresponding crosslinked MA‐bisF/BMI resin possesses a high content of fused‐ring structure and a high crosslinking density, so as to exhibit high thermal stability (392 °C), high glass transition temperature (262 °C), high char yield (48 wt%), and a low‐dielectric constant of 2.78 at 1 MHz. A new type of reactive polymers and the corresponding high‐performance crosslinked resins has been demonstrated.

Preparation of Meldrum's acid‐functionalized polyimides exhibiting organo‐soluble, reactive, self‐crosslinkable, and colorless features

“…This endothermic peak is attributed to the thermolysis reaction of MA groups. [31][32][33][34][35][36] Since MA thermolysis would evolve CO 2 and acetone byproducts, 31 F I G U R E 1 (A) 1 H NMR and (B) 13 PI(MADA-6FDA) also exhibits an obvious weight loss at the similar temperature region in thermogravimetric analysis (TGA). The weight loss of PI(MADA-6FDA) at this stage is about 12.8 wt%, which is coincident to the theoretical value of 12.4 wt% calculated from the MA fraction of PI(MADA-6FDA).…”

“…For MA-containing polymers, dimerization of ketene groups at high temperatures would bring crosslinked structures to the resulting polymers. [31][32][33][34][35][36] Consequently, PI(MADA-6FDA) has been thermally treated at 200 C for 1 h, 240 C for 1 h, and 280 C for 1 h to carry out the MA thermolysis andketene-dimerization reactions. The obtained crosslinked sample, coded as CRPI(MADA-6FDA), is subjected to thermal analysis.…”

“…32 The self-addition dimerization reaction of ketene groups also contributes to crosslinking polymer chains. [33][34][35][36] The synthesis route of MA-functionalized PIs needs a MA-containing diamine compound, MADA in this work, as a monomer. Synthesis and characterization of the MADA compound has been done in our laboratory and reported previously.…”

Recyclable biobased materials based on Diels–Alder cycloaddition

“…Several researchers have studied the application of the DA reaction to construct some reversible structures of linear polymers, and the kinetics of the simpler systems have been studied . In addition, a number of thermally reversible healing materials and biological materials have been constructed based on this DA reaction . Modified epoxy resin was chosen by some researchers to construct DA reversible materials .…”

Polymerization of Meldrum’s Acid and Diisocyanate: An Effective Approach for Preparation of Reactive Polyamides and Polyurethanes

“…Ketene has a high chemical reactivity toward nucleophiles such as hydroxyl, amine, and isocyanate groups to result in ester, amide, and azitidine-2,4-dione groups, respectively. ,, Dimerization reaction of ketene could also take place at high temperatures to generate the corresponding 1,3-butandione group . Based on the ketene chemistry, reactive polymers possessing MA groups were first reported with Hawker et al and then have received other researchers’ attention. − Reactive polymers possessing pendent MA groups have been prepared through radical polymerization, ring-opening metathesis polymerization, and step polymerization − with associated MA-containing monomers. Postfunctionalization and cross-linking reaction have been carried out on the polymers based on MA thermolysis reaction and ketene chemistry.…”