Epoxy polymer nanocomposites (PNCs) filled with both barium titanate (BaTiO 3 ) (500 and 100 nm) and conductive polyaniline (PANI) stabilized BaTiO 3 nanoparticles (NPs) have been successfully prepared. The effects of the BaTiO 3 nanofiller loading level and the PANI coating on the mechanical properties, rheological behavior, thermal stability, flammability and dielectric properties were systematically studied. The viscosity study on the nanosuspensions indicates that the PANI layer on the BaTiO 3 nanoparticle surface can promote the network formation of the epoxy resin. The introduction of the PANI layer was found to reduce the heat release rate and to increase the char residue of the epoxy resin. The dynamic storage and loss moduli were studied together with the glass transition temperature (T g ) obtained from the peak of tan d, and the reduced T g in the PNCs is associated with the enlarged free volume. The tensile test indicated an improved tensile strength of the epoxy matrix with the introduction of the BaTiO 3 NPs. Compared with the cured pure epoxy, the elasticity modulus was increased for all the PNC samples. The fracture surface study revealed an enhanced toughness. Due to the ferroelectric nature of BaTiO 3 , the real dielectric permittivity increased with increasing the BaTiO 3 nanoparticle loading. The PANI layer on the surface of BaTiO 3 also enhanced the dielectric permittivity arising from the interfacial polarization formed in the PNCs.

As a biobased and biodegradable polyester, polylactide (PLA) is widely applied in disposable products, biomedical devices, and textiles. Nevertheless, due to its inherent brittleness and inferior strength, simultaneously reinforcing and toughening of PLA without sacrificing its biodegradability is highly desirable. In this work, a robust assembly consisting of compact and well-ordered microfibrillar crystalline superstructure (FCS) surrounded by slightly oriented amorphism, is achieved by a combined external force field. Unlike the classic crystalline superstructures such as shish-kebabs, cylindrites, and lamellae, the newfound FCS with diameter of about 100 nm and length of several tens of micrometers is aggregated with well-aligned crystalline nanofibers. FCS can serve as discontinuous fiber to self-reinforce the amorphous PLA; more importantly, FCS can also act as rivets to pin the propagating fibrillar crazes leading to the formation of dense fibrillar crazes during stretching, which dissipates much energy and translates the failure of PLA from brittle to ductile. Consequently, PLA with FCS exhibits exceptionally simultaneous enhancement in ductility, strength, and stiffness, outperforming normal PLA with increments of 728, 55, and 70% in elongation at break, strength, and modulus, respectively. Therefore, FSC exhibits competitive advantages in achieving high-performance PLA even for other semicrystalline polymers. More significantly, this newfound crystalline superstructure (FCS) provides a new structural model to establish the correlation between structure and performance.

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Due to safety requirements, insensitive behaviour under slow thermal heating (cook-off) conditions is a desirable behaviour for today's munitions. In this paper a cook-off device is designed to test two groups of RDX-based PBX explosives. In the first group the binder type was varied and in the second group the binder content of the RDX-based explosive was changed. Eleven samples were examined in order to evaluate the influence of four different binders and seven different binder contents on the shell deformation and the degree of the involved reaction. The test results showed that the degree of the reaction can be improved by changing the binder content, but not by the binder type. This phenomenon was explained by the thermal-conduction theory.