Haihua Wang

Facile approach to fabricate waterborne polyaniline nanocomposites with environmental benignity and high physical properties

Waterborne polyaniline (PANI) dispersion has got extensive attention due to its environmental friendliness and good processability, whereas the storage stability and mechanical property have been the challenge for the waterborne PANI composites. Here we prepare for waterborne PANI dispersion through the chemical graft polymerisation of PANI into epichlorohydrin modified poly (vinyl alcohol) (EPVA). In comparison with waterborne PANI dispersion prepared through physical blend and in situ polymerisation, the storage stability of PANI-g-EPVA dispersion is greatly improved and the dispersion keeps stable for one year. In addition, the as-prepared PANI-g-EPVA film displays more uniform and smooth morphology, as well as enhanced phase compatibility. PANI is homogeneously distributed in the EPVA matrix on the nanoscale. PANI-g-EPVA displays different morphology at different aniline content. The electrical conductivity corresponds to 7.3 S/cm when only 30% PANI is incorporated into the composites, and then increases up to 20.83 S/cm with further increase in the aniline content. Simultaneously, the tensile strength increases from 35 MPa to 64 MPa. The as-prepared PANI-g-EPVA dispersion can be directly used as the conductive ink or coatings for cellulose fibre paper to prepare flexible conductive paper with high conductivity and mechanical property, which is also suitable for large scalable production.

Effects of Continuous Phase and Crosslinking Agent on the Rheological Behaviors and Properties of Cationic Poly(urethane-acrylate) Emulsifier-Free Microemulsions

Cationic poly(urethane-acrylate) emulsifier-free microemulsions are prepared by seeded emulsion polymerization (SPUA) or in-situ emulsion polymerization (IPUA) with (a) or without (b) crosslinking agent hydroxyethyl acrylate (HEA). Furthermore, no surfactant is introduced into the reaction system. The effect of continuous phase and HEA on the rheological behavior and properties of microemulsions are studied. The results show that IPUA using vinylmonomers as the continuous phase and with HEA (IPUAMB-b) has the highest ζ value, lowest coagulation ratio, smallest particle size of 48 nm and apparent core-shell structures. Rheological research has concluded that the zero-shear viscosity of IPUAB-b and IPUAM-b emulsion is 6.03×102 and 7.89 Pa·s, respectively, and presents pseudoplastic behavior. However, IPUAMB-b and SPUA-b display Newtonian behavior with η0 of 0.136 Pa·s and 0.0823 Pa·s, respectively. PUA emulsions display similar rheological behavior when NMP is replaced by the mixture of MMA and BA.