Maleimide end- capped polyether telechelics as novel toughening agents for unsaturated polyester resin

Preparation and properties of bismaleimide resin blended with alkynyl-terminated modifiers

A kind of modified bismaleimide resin, with good processability, heat resistance, and impact strength was developed, using 4,4′-dipropargyloxydiphenyl ether (DPEDPE), N-(4-propargyloxyphenyl)maleimide (4-PPM), and 3-ethynylphenyl maleimide (3-EPM) as modifiers. The DPEDPE, 4-PPM, and 3-EPM were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR) and 1H-nuclear magnetic resonance (1H NMR), and used to modify the N,N′-(4,4′-diphenylmethane)bismaleimide (BDM)/2,2′-diallyl bisphenol A (DABPA) resin system (BD) to obtain the different blend resin systems of DPEDPE-modified BD (BDD), 4-PPM-modified BD (BDP), and 3-EPM-modified BD (BDE). The curing temperature of BD resin increases with increase of the alkynyl-terminated modifier content. The processability of BD resin was improved with addition of the propargyloxy-terminated compounds. The temperature of 5% weight loss, residual yield at 800°C and glass transition temperature of the cured BD resin increase with increase of the alkynyl-terminated modifier content and can reach 443°C, 46.7% and higher than 380°C. The tensile strength of the cured BD resin decreases with increase of alkynyl-terminated modifier content. The impact strength of the cured BD resin increases with increase of the propargyloxy-terminated compound content and can increase by 65%. The tensile strength, elastic modulus, and impact strength of the cured BD resin blended with DPEDPE can be 73.7 MPa, 4.1 GPa, and 19.6 kJ m−2, respectively. Moreover, the cured BD resin blended with DPEDPE has good water absorption resistance.

Force-Induced Self-Assembly of Supramolecular Modified Mica Nanosheets for Ductile and Heat-Resistant Mica Papers

Mica is a naturally abundant layered silicate mineral that has higher strength than other layered silicate minerals, but its inherent brittleness limits its application in some fields. In this work, mica was ultrasonically exfoliated into a single-layered nanomaterial after thermal activation, acidification, sodium replacement, and cetyltrimethylammonium bromide (CTAB) intercalation and then modified with ureido-pyrimidinone (UPy)-based PEG chains. Vacuum-assisted self-assembly was used to construct supramolecularly modified single-layered mica into bulk materials, in which the mica nanosheets were stacked into mica paper. The reversible quadruple hydrogen-bonded UPy moieties provided a high binding constant and significantly improved the strength and toughness of the obtained mica paper. These force-induced assembled mica papers showed significantly improved tensile strength and toughness compared with pure mica paper and simultaneously maintained the heat resistance of the mica materials, which may be good candidates for the substrates of flexible sensors working at higher temperatures.