Property and morphology relationships for ternary blends of polycarbonate, brittle polymers and an impact modifier

Enhancing the dielectric and thermal properties of polytetrafluoroethylene-based composites through designing and constructing a novel interfacial structure

Polytetrafluoroethylene (PTFE) is widely used as a fundamental core material for high-frequency and high-speed signal transmission fields due to its excellent dielectric properties. However, the high coefficient of thermal expansion (CTE) characteristic of PTFE severely limits its practical application. The CTE of PTFE can be reduced by filling with SiO2, which is always accompanied by a rapid deterioration of dielectric properties due to the poor interfacial compatibility between SiO2 and PTFE matrix. In this paper, the challenge of synergistic regulation of dielectric and CTE properties for PTFE-based composites is overcome by constructing an interfacial structure with physical interactions. Micro-mesoporous SiO2 (mSiO2) is prepared and introduced as a filler, compared with smooth surface SiO2 (sSiO2), the presence of micro-mesoporous in mSiO2 allows PTFE molecular chains to be adsorbed on the surface or in the pore channels of mSiO2, which improves the interfacial combination of the mSiO2/PTFE composites through the physical interaction between mSiO2 and PTFE. The results show that mSiO2/PTFE composite exhibits a lower CTE (58 ppm °C-1) while maintaining a lower dielectric constant (εr, 2.29, 30 GHz) with dielectric loss (tan δ, 2.31 × 10-3, 30 GHz) at a filler addition of 30 vol%, as compared with that of the sSiO2/PTFE composites. This work provides a new strategy for fabricating PTFE-based composites with low CTE as well as low εr and tan δ.

Novel biobased high toughness PBAT/PEF blends: morphology, thermal properties, crystal structures and mechanical properties

A novel series of PBAT/PEF blends with 1–50 wt% PEF content displayed typical sea-island morphology structure and had excellent toughness properties.

Molecular design of near-IR dyes with different surface energy for selective loading to the heterojunction in blend films

We have synthesized three silicon phthalocyanine dyes with different hydrophobic substituents in order to control surface energy in the solid state, aiming at selective loading of the dyes into blend films of poly(3-hexylthiophene) (P3HT) and polystyrene (PS). These three dyes are differently located at P3HT domains, at P3HT/PS interface, and at PS domains, respectively, which are fully consistent with the locations predicted by the wetting coefficient derived from the surface energy of each material.