Several toughening and crosslinking modifiers were tested in two epoxy resin systems based on the diglycidyl ether of bisphenol A (DGEBA) with the objective to improve the critical stress intensity factor KIC and the glass transition temperature (Tg) simultaneously. An amine hardener (isophorone diamine (IPD)) and a homopolymerization initiator (1‐ethyl‐3‐methylimidazolium acetate (EMIM Ac)) were used as curing agents. The highest effect on the KIC value of the resin system DGEBA/IPD (KIC = 0.72 MPa1/2; Tg = 164°C) was achieved with the dendric polymer Boltorn P501 (10 wt%), but it decreased the Tg (KIC = 1.39 MPa1/2; Tg = 136°C). A high toughening effect with a low decrease of Tg was achieved with a combination of a self‐organized block copolymer (Nanostrength M22N) and silica nanoparticles (Nanopox F400) (KIC =1.15 MPa1/2; Tg =157°C). The KIC value of the resin system DGEBA/EMIM Ac was improved from 0.44 to 0.66 MPa1/2. An improvement of both, the thermal and mechanical properties was established for a combination of a poly(tetrahydrofuran) as toughening modifier (PolyTHF2000) with the post‐crosslinking modifier diethylphosphite (DEP) in the resin system DGEBA/IPD (KIC = 0.86 MPa1/2; Tg = 180°C). A system with chemical linkages between both modifiers was investigated for comparison but yielded inferior results. POLYM. ENG. SCI., 59:86–95, 2019. © 2018 Society of Plastics Engineers

The media advertizes that soon everybody can manufacture models and parts of all kinds via computer-aided design -computer-aided manufacturing by additive manufacturing (AM) technologies. That can boost the do-it-yourself activities enormously. But it can also revolutionize the industries: Most conventional technologies of manufacture are profitable only in big lots of production. For single specimens and small lots of production, they are too expensive. But with AM, one or a few original or spare parts can be produced at low cost. However, to succeed in the market, the AM products must become competitive. They must have reproducibility of an exact shape, even in tiny details, a perfect surface and, above all, sufficient mechanical strength. This article deals with three-dimensional ink-jet printing with monomer inks and polymer powders. Since powder beds are always porous, the main aim was to fill the pores permanently with high amounts of the ink polymer. A new polyme r powder that rapidly dissolves in monomer inks is reported

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