A New Hyperbranched Poly(arylene−ether−ketone−imide):  Synthesis, Chain-End Functionalization, and Blending with a Bis(maleimide)

Abstract

While aromatic polyimides have found widespread use as high-performance polymers, the present work addressed the need for organosoluble pre-imidized materials through the use of a hyperbranching scheme. The AB 2 monomer, N- [3,5-bis(4-hydroxybenzoyl)benzene]-4-fluorophthalimide, was prepared from 4-fluoroisophthalic anhydride and 3,5-bis(4-hydroxybenzoyl)aniline. The latter was synthesized in three steps starting from commercially available 5-nitroisophthalic acid. The AB2 monomer was then polymerized via aromatic fluoride-displacement reaction to afford the corresponding hydroxylterminated hyperbranched polymer, HT-PAEKI, which was then functionalized with allyl and propargyl bromides as well as epichlorohydrin to afford allyl-terminated AT-PAEKI, propargyl-terminated PT-PAEKI, and epoxy (glycidyl)-terminated ET-PAEKI, in that order. All hyperbranched poly(ether-ketoneimide)s were soluble in common organic solvents. Intrinsic viscosities of HT-, AT-, PT-, and ET-PAEKI in NMP were 0.13, 0.08, 0.08, and 0.08 dL/g, in that order. AT-PAEKI displayed an exotherm due to Claisen rearrangement at 269 °C and allyl-based thermal-cure reaction at 343 °C. PT-PAEKI displayed only a single, strong exotherm at 278 °C. Because of hydrogen bonding, HT-PAEKI displayed T g of 224 °C while its derivatives exhibited lower Tg values ranging from 122 to 174 °C. Finally, AT-PAEKI was blended with a bisphenol A-based bis(maleimide) (BPA-BMI) in various weight ratios. The results from differential scanning calorimetric study indicated that the presence of AT-PAEKI (up to 32 wt %) significantly affect the glass transition temperatures and cure behavior of BPA-BMI. Dynamic mechanical analysis comparing cured BPA-BMI with the 5 wt % AT-PAEKI blend corroborates this increase in glass transition temperature.

Modification of bisphenol-A based bismaleimide resin (BPA-BMI) with an allyl-terminated hyperbranched polyimide (AT-PAEKI)

“…The preparation of AT-PAEKI was described in our previous paper [26] and the BPA-BMI was obtained via a custom synthesis by University of Dayton Research Institute. All the solvents and other chemicals involved were purchased from commercial sources and used as received.…”

“…However, because the aliphatic polyester possesses low thermal stability and modulus, these systems showed significant compromise in either T g or modulus. Recently, a plethora of heat-resistance HBPs, such as hyperbranched PEK [7,9,[19][20][21], ether imide [10,[22][23][24][25][26][27], aromatic polyester [4,28] and aromatic polyamide [8,29,30], have been reported. Despite this great variety, no study on the toughening of epoxy or BMI resin with any of these HBPs has been reported.…”

Modern advances in bismaleimide resin technology: A 21st century perspective on the chemistry of addition polyimides

“…Qin et al synthesised an allyl terminated hyperbranched poly(ether-ketone-imide) ( Figure 20) as a BMI modifier to try and overcome the shortcomings associated with the aliphatic polyesters used previously [87,88]. Unusually for a toughening additive, this approach led to improvements in all of the key areas of processability, Tg (from 244 to 264 °C), modulus (from 3.4 to 3.8 GPa) and fracture toughness (from 0.48 to 0.55 MPa m 1/2 ).…”

Aromatic Hyperbranched Polymers: Synthesis and Application

“…The self-polycondensation was carried out through the nucleophilic etherification of silylated phenol and aryl fluoride in diphenylsulfone at 240 C in the presence of cesium fluoride. Other AB 2 -type monomers were also prepared for the synthesis of hb-PIs via nucleophilic etherification, as shown in 1-11, Scheme 8 [131].…”