Natural Rubber Based Composites Comprising Different Types of Carbon-Silica Hybrid Fillers. Comparative Study on Their Electric, Dielectric and Microwave Properties, and Possible Applications

The paper presents a comparative study on the electric, dielectric and microwave properties of natural rubber based composites comprising dual phase fillers prepared from furnace carbon black or conductive carbon black with a different amount of silica. It has been established that, the specifics of the carbon phase have a marked strong effect upon the properties mentioned above. The interpenetration of the two filler phases and the grade of isolation of the conductive carbon phase by the dielectric one depend on the ratio between them. On the other hand, that leads to a change in all properties of the studied composites, which allows tailoring those characteristics.

Preparation of Polylactide/Poly(ether)urethane Blends with Excellent Electro-actuated Shape Memory via Incorporating Carbon Black and Carbon Nanotubes Hybrids Fillers

In this work, hybrid conductive fillers of carbon black （CB） and carbon nanotubes （CNTs） were introduced into polylactide （PLA）/thermoplastic poly（ether）urethane （TPU） blend （70/30 by weight） to tune the phase morphology and realize rapid electrically actuated shape memory effect （SME）. Particularly, the dispersion of conductive fillers, the phase morphology, the electrical conductivities and the shape memory properties of the composites containing CB or CB/CNTs were comparatively investigated. The results suggested that both CB and CNTs were selectively localized in TPU phase, and induced the morphological change from the sea-island structure to the co-continuous structure. The presence of CNTs resulted in a denser CB/CNTs network, which enhanced the continuity of TPU phase. Because the formed continuous TPU phase provided stronger recovery driving force, the PLA/TPU/CB/CNTs composites showed better shape recovery properties compared with the PLA/TPU/CB composites at the same CB content. Moreover, the CB and CNTs exerted a synergistic effect on enhancing the electrical conduetivities of the composites. As a result, the prepared composites exhibited excellent electrically actuated SME and the shape recovery speed was also greatly enhanced. This work demonstrated a promising strategy to achieve rapid electrically actuated SME via the addition of hybrid nanoparticles with self-networking ability in binary PLA/TPU blends over a much larger composition range.

Recent Progress in Fabrication and Structural Design of Thermal Conductive Polymer Composites

In recent years, the demand direction for electronic equipment has expanded into embedded and miniaturized devices. The heat radiation problem has become one of the most significant factors for hindering the development of electronic devices. Since heat radiation material is one of the important components in electronic devices, the demand for enhancing thermal conductivity is also increasingly urgent. Research on thermal conductive polymer composites has become a major direction for developing functional composites. This work reviewed the recent progress in the fabrication of thermal conductive polymer composites. Five different structures are presented, including the using of single fillers,hybrid fillers, double threshold percolation structure, segregated structure and other complex multiphase structures. Specifically, the preparation of high-performance thermal conductive polymer composites was introduced through the combination of various thermal conductive fillers.Finally, the development direction of high thermal conductive polymer composites was briefly explored.

Hybrid Straw/Perlite Reinforced Natural Rubber Biocomposites

The purpose of the work is to prepare and characterize hybrid fillers of cereal straw perlite as well as to examine their impact on the functional properties of elastomeric biocomposites.Natural rubber was used as the polymer matrix,vulcanized with a sulfuric crosslinking system.The subject matter of the work included an interdisciplinary knowledge segment in the field of polymertechnology—hybrid biomaterials.The work investigated the effect of physical(mecha nical)modificatio n of ligno cellulosic filler.The process of milling and homogenization of cereal straw with the addition of perlite was carried out in a planetary ball mill.The properties of biocomposites were examined in terms of two key aspects:The amount of hybrid filler and its ratio(cereal straw to natural mineral).The plate-like structure of natural minerals and the fibrous structure of cereal straw created a two-component filler,which influenced the properties of the produced biomaterials.A significant improvement in barrier,crosslinking density,hardness,mechanical and damping properties has been noted for systems containing hybrid fillers.Moreover,all vulcanizates proved to be resistant to the nnooxidative aging.Furthermore,the straw modificated with perlite fonned a more complex structure in the composites,resulting in a stronger reinforcing effect,which was confirmed by dynamic-mechanical analysis(Payne effect).

Simultaneously Improved Dielectric Constant and Breakdown Strength of PVDF-based Composites with Polypyrrole Nanowire Encapsuled Molybdenum Disulfide Nanosheets

High-performance dielectric polymer composites have received increasing attention due to their important applications in the field of energy storage.The rational structural design of hybrid fillers can lead to a balance between high dielectric constant and insulation in composites.In this work,novel hybrid fillers were fabricated by in situ synthesizing one-dimensional polypyrrole nanowires(PPynws)on the twodimensional molybdenum disulfide(MoS_(2)),which integrated the good ion polarization ability of PPynws and the high insulation and adjustable band gap of MoS_(2).Compared with the binary poly(vinylidene fluoride)(PVDF)/MoS_(2) composites,the PVDF/MoS_(2)-PPynws composites exhibited remarkably improved dielectric constant and breakdown strength,while the dielectric loss was still maintained at a low level.An optimal ternary composite with 1 wt%MoS_(2)-PPynws showed a high dielectric constant(15@1kHz),suppressed dielectric loss(0.027@1kHz),and high breakdown strength(422.1 MV/m).PPynws inducing strong interfacial polarization and the highly insulated MoS_(2) nanosheets extending the breakdown path mainly contributed to the synchronously enhanced dielectric constant and breakdown strength.This intriguing synthesis method of PVDF/MoS_(2)-PPynws nanocomposite will open up new opportunities for fabricating nanostructured polymer composites to produce high dielectric materials.

Preparation of Nylon MXD6/EG/CNTs Ternary Composites with Excellent Thermal Conductivity and Electromagnetic Interference Shielding Effectiveness

In this article, hybrid fillers with different dimensions, namely, 2-dimensional（2-D） expanded graphite（EG） and 1-dimensional（1-D） multi-walled carbon nanotubes（CNTs）, were added to aromatic nylon MXD6 matrix via melt-blending, to enhance its thermal and electrical conductivity as well as electromagnetic interference shielding effectiveness（EMI SE）. For ternary composites of MXD6/EG/CNTs, the electrical conductivity reaches up nine orders of magnitude higher compared to that of the neat MXD6 sample, which turned the polymer-based composites from an insulator to a conductor, and the thermal conductivity has been enhanced by 477% compared with that of neat MXD6 sample. Meanwhile, the EMI SE of ternary composite reaches ~50 d B at the overall filler loading of only 18 wt%. This work can provide guidance for the preparation of polymer composites with excellent thermal and electrical conductivity via using hybrid filler.