This study describes a simple and effective method of synthesis of a polyurethane/graphene nanocomposite. Cationic waterborne polyurethane (CWPU) was used as the polymer matrix, and graphene oxide (GO) as a starting nanofiller. The CWPU/GO nanocomposite was prepared by first mixing a CWPU emulsion with a GO colloidal dispersion. The positively charged CWPU latex particles were assembled on the surfaces of the negatively charged GO nanoplatelets through electrostatic interactions. Then, the CWPU/chemically reduced GO (RGO) was obtained by treating the CWPU/GO with hydrazine hydrate in DMF. The results of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Raman analysis showed that the RGO nanoplatelets were well dispersed and exfoliated in the CWPU matrix. The electrical conductivity of the CWPU/RGO nanocomposite could reach 0.28 S m⁻¹, and the thermal conductivity was as high as 1.71 W m⁻¹ K⁻¹. The oxygen transmission rate (OTR) of the CWPU/RGO-coated PET film was significantly decreased to 0.6 cm³ m⁻² day⁻¹, indicating a high oxygen barrier property. This remarkable improvement in the electrical and thermal conductivity and barrier property of the CWPU/RGO nanocomposite is attributed to the electrostatic interactions and the molecular-level dispersion of RGO nanoplatelets in the CWPU matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43117.

The design, preparation, and properties of two DOPO-containing compounds based on a cardanol-allylamine-paraformaldehyde benzoxazine (abbreviated as BZc-a) were described in this article. By controlling the amount of DOPO, it could react with BZc-a and generated different products. When DOPO: BZc-a <1 : 1, DOPO reacted only with allyl group, and generated a containing single DOPO group benzoxazine (P₁B); When DOPO: BZc-a ≧ 1 : 1, DOPO reacted not only with allyl group but also nucleophilic addition reaction, got a N-substituted derivative P₂B, which contain double DOPO groups. The chemical structure of P₁B and P₂B was characterized by ¹H-NMR and ¹³C-NMR. Effect of DOPO on characteristics of BZc-a was investigated. Fire test demonstrated that P₁B and P₂B showed better flame retardance than BZc-a, and prepared two kinds of flame-retardance resin based on BZc-a. However, Field emission electron microscope observations showed the surface of P₁B and P₂B was very fragility, graphene oxide (GO) was chosen as to improve the surface performance. P₁B/GO-3 wt % and P₂B/GO-3 wt % composites were prepared by solution blending, and the thermal stability was studied by thermogravimetric analysis. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41634.

Multi-hollow or hollow polymer particles are of great interest in many fields. Here we successfully fabricate polystyrene microspheres with aqueous cores through w/o/w Pickering emulsion stabilized by modified SiO₂ nanoparticles. The final structure and constituents of the microspheres is investigated via SEM, X-ray photoelectron spectra, and thermo-gravimetric analysis. The results demonstrate that the size and amount of aqueous cores in the microspheres can be tuned by the original structure of the multiple emulsions: when the volume fraction of inner water is 0.2, the inner structure of the microspheres obtained is porous and each pore is not interconnected; when the volume fraction of inner water is increased to 0.7, the resulting products are hollow microspheres and when 0.3% wt/vol of salt is added to the inner aqueous phase, the inner pores of the resulting microspheres enlarge or even coalesce. The multi-hollow or hollow polystyrene microspheres with aqueous cores are expected to be candidates for encapsulation in biotechnology. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39761.

A novel liquid benzoxazine was synthesized by Mannich reaction of cardanol, paraformaldehyde, and allylamine. The benzoxazine structure was characterized by ¹H-NMR and FTIR. The liquid benzoxazine could dissolve easily in many solvents. The curing behavior of the benzoxazine was characterized by differential scanning calorimetry (DSC) and its curing temperature was about 233°C. A benzoxazine-functional silane coupling agent (BFSca) was synthesized with paraformaldehyde, phenolphthalein, and aminopropyltriethoxysilane. Graphene oxide (GO) was also made via improved Hummer's method. Then benzoxazine/GO composites were prepared using BFSca by solution blending and the curing behaviors of the composites were also characterized by IR, DSC, and thermogravimetric analysis. The minimum curing temperature and the highest 5% weight loss temperature for the composites was, respectively, 185 and 399.8°C. The SEM images of benzoxazine/GO composites demonstrated that BFSca had improved the dispersion of GO in the benzoxazine and also enhanced the thermal decomposition temperature of the composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40353.