Calcium copper titanate (CaCu3Ti4O12; CCTO)/polyimide (PI) composite films were synthesized by 4,4′-oxydianiline, CCTO, and 3,3′,4,4′-biphenyltetracarboxylic dianhydride through ultrasonic dispersion in situ polymerization. Scanning electron microscopic images clearly confirmed that 10 wt% CCTO particles dispersed uniformly in composite films. When the content was 20–80 wt%, CCTO particles were coated by PI in good condition, and globular particles dispersed in the composite films. PI and CCTO/PI were found to exhibit excellent thermal stability. The addition of CCTO has influence on the thermal properties of PI. Weight loss temperatures (5% and 10%) of the composite films containing 70 wt% CCTO reached 612°C and 673.9°C, respectively. The strong interfacial interaction between PI and CCTO improved the dielectric properties of the composite films. The dielectric permittivity and conductivity of the CCTO/PI composite films increase with the increase of CCTO content. In addition, the dielectric permittivity of films containing 40–70 wt% increased rapidly.

Abstract. In this work, one-component moisture-cure polyurethane was synthesized, which is mainly used as adhesives for bonding wood. The properties of the polyurethane were characterized by Fourier Transform Infrared Spectroscopy(FTIR), thermal gravimetric analysis(TGA), dynamic mechanical thermal analysis(DMA) and electronic universal testing machine. The results indicate that the shear strength and tensile strength increase with increasing of NCO/OH ratio in 2 to 4, however, when the ratio more than 4, it will be decreased gradually. The TGA and DMA results show that the polyurethane film has relatively high thermal stability with a weight loss of 5% at 298 °C and the glass transition temperature is 97.52 °C.

With the rapid development of the electronics industry, the dielectric materials with high energy storage density, fast charge and discharge speed, easy-to-process and easy-to-mold, and stable performance are urgently needed to meet the requirements for lightweight and miniaturization of electronic component equipment. Dielectric ceramics has a high dielectric constant, but low breakdown field strength. Polyvinylidene fluoride (PVDF) has the advantages of good flexibility, high breakdown field strength, and light weight, but its dielectric constant is low. Achieving the ability to tailor the interface between dielectric ceramics filler and PVDF polymer matrix is a key issue for realizing the desirable dielectric properties and high energy density in the nanocomposites. As a result, much effort has been made to prepare the polymer composites through the surface modification of the nanoparticles with high dielectric constant fillers dispersed in a matrix, with the hope of preparing composites containing the high dielectric constant of the ceramic fillers and the high breakdown strength of polymers. In this work, in order to obtain the high dielectric-constant and high-energy-storage-density dielectric ceramics, the electrospinning method is used to prepare the SrTiO₃ one-dimensional nanofibers as the inorganic fillers and the casting method is adopted to prepare PVDF as the polymer matrix. To improve the interface between inorganic nanofiber fillers and PVDF matrix, the SrTiO₃ nanofibers are modified by surface hydroxylation. The effects of suface hydroxylated SrTiO₃ nanofibers on the dielectric properties and energy storage properties of PVDF composites are studied. The correlation between interface modification and energy storage performance of composites is investigated to reveal the mechanism of enhanced energy storage performance of SrTiO₃ nanofibers/PVDF composites. The results show that the dispersion of surface-hydroxylating SrTiO₃ nanofibers in PVDF polymer can be improved. The composites exhibit improved dielectric properties and enhanced breakdown strength. When the filling quantity of the surface-hydroxylating SrTiO₃ nanofiber fillers is 2.5 vol%, the energy storage density of the composite reaches 7.96 J/cm³. Suface-hydroxylating SrTiO₃ nanofibers exhibit excellent dispersion in the PVDF polymer matrix and strong interfacial adhesion with the matrix, leading the composites to possess excellent dielectric constant and energy storage performance. The surface hydroxylation of ceramic fillers can improve the energy storage performance of the composites.

A series of oil in water (O/W) microemulsions were prepared through drop by drop method at constant temperature, taking Span80/Tween80 as a composite emulsifying system and Macol-52 as oil phase. Effects of the mass ratio of composite emulsifying system and oil/emulsifier ratio on the particle size were studied. Finally, the best technological conditions were selected and the stability of the microemulsion was also researched. Results showed that the most suitable Span80/Tween80 mass ratio was 1:1 and the oil/emulsifier ratio is 1:1. Under this condition, the mean particle size of the o/w microemulsion was 71.1 nm and the polydispersity index was 0.151. Moreover, the microemulsion maintain a bright and uniform stable system after 20minutes’ centrifugation at the speed of 4000r/min and the particle size increased slightly.

Abstract-A novel solvent-free photosensitive polyester based on the hyperbranched aliphatic polyesters has been studied. The hyperbranched aliphatic polyesters (Polymer A), which was prepared from 2,2-dihydroxymethyl butyric acid(DMBA) containing one carboxylic group and two hydroxylic groups, Trimethylolpropane(TMP) and ptoluence sulfonic acid(p-TSA) as a catalyst, of which the degrees of branching (DB) was 0.53 according to definitions by Fréchet. Followed by end-modified with maleic anhydride(MA), end-modified hyperbranched aliphatic polyesters (polymer B) with unsaturated end groups was successfully synthesized. The properties of products were characterized by FI-IR, 13 C NMR, GPC, TGA，respectively. The UV-cured Polymer B based on polymer B, 4 wt% 1173 as photoinitiator, and Laromer R TPGDA(6:1) as reactive diluent was obtained, and was exposed for about 1s (2.2KW UV exposure apparatus). Therefore, the UV-cured Polymer B was obtained and regarded as a promising photosensitive material.