Dgeba

Bisphenol A diglycidyl ether (DGEBA; YD 128) as the epoxy matrix was supplied by Kukdo Chemical Co. (Seoul, Korea) its epoxide-equivalent weight was 185–190 g·equiv⁻¹. PEI as a thermoplastic toughener was supplied by Sigma-Aldrich Co. (St. Louis, MO, USA), with average molecular weights of Mw = 25,000 and Mn = 10,000, viscosity of 15,000 mPa·s at 50 °C, and density of 1.27 g·cm⁻³ at 25 °C. 4,4′-Diaminodiphenylmethane (DDM) and methylene chloride (MC), as the curing agent and solvent, respectively, were obtained from Sigma-Aldrich Co. The chemical structures of DGEBA, PEI, and DDM are shown in Figure 1.

The DGEBA (Bisphenol A diglycidyl ether), the 4,4′-diaminodiphenylsulfone (DDS) were purchased from Sigma-Aldrich. Bentonite was purified according to a standard procedure^{64 (link)} resulting in ∼80-μm-sized bentonite (B). The cationic exchange capacity (CEC) was equal to 101.9 meq/(100 g of clay). Fe₃O₄ nanopowder (Sigma Aldrich, 97% purity, 50–100 nm), N-phenyl-p-phenylenediamine (Acros, 98% purity), isopentyl nitrite (Alfa Aesar, purity 97%), ammonium persulfate (APS, Acros, 98% purity), and nitric acid (Carlo Erba, 60% purity). Aniline (Aldrich, 99.5% pure) was purified and stored at low temperature before usage. Distillated water for cleaning and dilutions was used throughout.

The analysis of monomers was performed according to Reichl et al. [30 (link)] with minor modifications. Chromatography was performed on an HP 5890 (Hewlett Packard, Palo Alto, CA, USA) coupled to a 5971 MSD using an HP-1MS column (12 m, inner diameter 0.2 mm, film thickness 0.33 µm) at an injection temperature of 280 °C, a constant oven temperature of 70 °C for 3 min, followed by a temperature gradient of 30 °C/min to 300 °C and a constant temperature of 300 °C for another 6 min, and an interface temperature of 280 °C. Helium was used as the carrier gas at a constant pressure of 24 kPa. The monomers were extracted twice in ethyl acetate and the solutions were evaporated at room temperature in a N₂ stream to a residual volume of about 150 µL. Monomers were identified based on their retention times and masses using caffeine as an internal standard (Table 1).
In addition to the measured monomer concentrations in the eluates, the eluted monomer amounts were calculated according to the respective specimen volume. UDMA was purchased from Polysciences Europe GmbH (Hirschberg an der Bergstraße, Germany), MMA from DENTAURUM GmbH & Co. KG (Ispringen, Germany) and BDMA, DGEBA and DGEBF from Sigma Aldrich (Taufkirchen, Germany).

DGEBA, having an epoxy equivalent weight (EEW) of 170.21 g eq⁻¹, (Sigma-Aldrich, St. Louis, MO, USA) was used as the main base of epoxy resin in the formulated mixture. Hyperbranched epoxy resin was synthesized and characterized via FTIR and NMR techniques. The results are shown in Figures S1 and S2, respectively. The chemical for the synthesis: BPA (Tokyo Chemical Industry Co., Ltd., Tokyo, Japan) was used as an aromatic monomer, and was purified via recrystallization using toluene before use. PEG400, Mw = 400 g/mol, (Sigma-Aldrich, St. Louis, MO, USA) was used as an aliphatic monomer. Epichlorohydrin (ECH), (Tokyo Chemical Industry Co., Ltd., Tokyo, Japan) was used as an epoxidation reagent. PE (Tokyo Chemical Industry Co., Ltd., Tokyo, Japan) was used as a branch generating unit and was recrystallized with ethanol before use. Sodium hydroxide (NaOH) as a base catalyst and sodium chloride (NaCl) were obtained from Ajax Finechem, Sydney, Australia. Hydrobromic acid (HBr), acetic acid, potassium acid phthalate, methyl violet, and chlorobenzene (Tokyo Chemical Industry Co., Ltd., Tokyo, Japan) were used to determine the epoxy equivalent weight (EEW) following the standard test methods (ASTM D 1652) [23 ]. Triarylsulfonium hexafluorophosphate salts (Sigma-Aldrich, St. Louis, MO, USA) were used as a photoinitiator.

Ammonium heptamolybdate [(NH₄)₆Mo₇O₂₄·4H₂O], thiourea and oleyl alcohol (OA) were purchased from Sinopharm Chemical Reagent Beijing Co., Ltd. Oleylamine (OM) was purchased from J&K Scientific. Deionized water was used and all the chemicals were used as received. Diglycidyl ether of bisphenol A (DGEBA, Sigma-aldrich, DER 332), adipic acid (TCI > 99.0%), Triazobicyclodecene (TCI 98%), Triazobicyclodecene (Sigma-aldrich 98%) and sebacic acid (Aladdin, CP) were used directly without further purification.

Maleic anhydride (99%), 5-aminoisophtalic acid (94%), diglycidyl ether of bisphenol A (DGEBA, epoxide equivalent weight 188 g·eq.⁻¹), acetic acid, benzyltriethylammonium chloride (TEBAC, 99%), anthracene, methanol, N-methylpyrrolidone (NMP), ethylene glycol butyl ether (BEG), 2-methoxyethanol, and methanol were purchased from Sigma Aldrich, Darmstadt, Germany. All reactants and solvents were analytical grade and were used as received.