Epoxy resin, modified with different particle sizes (50 nm, 100 nm, 200 nm) and contents (1 wt %, 3 wt %, 5 wt %, 7 wt %) was manufactured. The mechanical behaviors of tensile, quasistatic fracture and dynamic fracture under SHPB (split Hopkinson pressure bar) loading were investigated. The dynamic fracture behaviors of the composites were evaluated by 2D-DIC (digital image correlation) and the strain gauge technique, and the fracture surface was examined by SEM (scanning electron microscope). According to the results, the tensile modulus and strength significantly increased for epoxy resin modified with 5 wt % Al2O3 of 50 nm. The quasistatic fracture toughness of modified epoxy resin increased with the particle content. However, the fracture toughness of epoxy resin modified with high content fillers decreased for particle agglomeration that existed in epoxy resin. The crack propagation velocity can be decreased for epoxy resin modified with particles under dynamic loading. The dynamic initiation fracture toughness of modified epoxy resin increases with both particle size and content, but when the fillers have a high content, the particle size effects are weak. For the composite under dynamic loading conditions, the toughening mechanism is also affected by particle size.

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Janus particles (JPs) are a new type of compatibilizer for polymer blends that offer a wider range of adjustable amphiphilic (Janus balance) and reactivity properties. In this study, snowman-like JPs with different compositions on two lobes are synthesized and employed as compatibilizers for poly(lactic acid)/ poly(butylene succinate) (PBS) blends. By changing the two lobe size ratios and surface compositions to adjust the Janus balance, interfacial distributions of the as-used JPs in the blends can be controlled. Correspondingly, the size of the PBS dispersed phase is tuned. Most importantly, reactive groups are introduced into JPs to enhance interfacial interactions. Compared to the effect of dispersed phase size reduction, the ductility and toughness of blends with the JPs are more significantly enhanced by improving interactions between the JPs and blend phases. When JPs are anchored to the interface, the elongation at break and tensile toughness of the blend increase by 13.1 and 16.4 times, respectively.

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