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In this study, core‐shell structured cationic waterborne polyurethane (WPU) dispersions with high solid content were prepared. To this end, prepolymer A was synthesized from polytetramethylene ether glycol (PTMG), isophorone diisocyanate (IPDI), castor oil (CO) and 1,4‐butanediol (BDO) without integration of the hydrophilic groups. Prepolymer B with hydrophilic groups was prepared from PTMG, IPDI, CO, BDO and N‐methyldiethanol amine (MDEA). WPU dispersion with a core‐shell structure could be generated by mixing, neutralizing, and emulsifying of the prepolymer A and the prepolymer B. The results indicated that the generation of WPU dispersions through this technique exhibited a milky appearance while the pH values range from 5.30 to 5.60. The optimal combination of prepolymer A and prepolymer B (at a ratio of 5:5) resulted in a dispersion with the highest solid content (50.4%), lowest viscosity (69 mPa·s), and narrowest particle size distribution. As the proportion of prepolymer A to prepolymer B decreases, the tensile strength of WPU film reduces while the elongation at break and glass transition temperature increases. Moreover, initially the contact angle with water was decreased instead of increase. However, modifications in a ratio of prepolymer A and B was not showed any significant impact on the thermal stability performance of the WPU films. [ABSTRACT FROM AUTHOR]

Vinyl-capped cationic waterborne polyurethane (CWPU) was prepared using isophorone diisocyanate (IPDI), polycarbonate diol (PCDL), N-methyldiethanolamine (MDEA), and trimethylolpropane (TMP) as raw materials and hydroxyethyl methacrylate (HEMA) as a capping agent. Then, a crosslinked FPUA composite emulsion with polyurethane (PU) as the shell and fluorinated acrylate (PA) as the core was prepared by core-shell emulsion polymerization with CWPU as the seed emulsion, together with dodecafluoroheptyl methacrylate (DFMA), diacetone acrylamide (DAAM), and methyl methacrylate (MMA). The effects of the core-shell ratio of PA/PU on the surface properties, mechanical properties, and heat resistance of FPUA emulsions and films were investigated. The results showed that when w(PA) = 30~50%, the stability of FPUA emulsion was the highest, and the particles showed a core-shell structure with bright and dark intersections under TEM. When w(PA) = 30%, the tensile strength reached 23.35 ± 0.08 MPa. When w(PA) = 50%, the fluorine content on the surface of the coating film was 14.75% and the contact angle was as high as 98.5°, which showed good hydrophobicity; the surface flatness of the film was observed under AFM. It is found that the tensile strength of the film increases and then decreases with the increase in the core-shell ratio and the heat resistance of the FPUA film is gradually increased. The FPUA film has excellent properties such as good impact resistance, high flexibility, high adhesion, and corrosion resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Poly(hexamethylene guanidine hydrochloride) (PHMG) with 98 wt% type B was synthesized. • PHMG was introduced into anionic/cationic waterborne polyurethane (AWPU/CWPU). • PHMG incorporation resulted in higher particle sizes in AWPU, but in lower particle sizes in CWPU. • PHMG appeared no antibacterial activity in AWPU due to electronic attraction, but high antibacterial activity in CWPU. Antibacterial materials are widely used in various fields, and Poly(hexamethylene guanidine hydrochloride) (PHMG) is an effective broad-spectrum antibacterial agent with great potential in preparing antibacterial materials. Therefore, in this work, type B PHMG was prepared and incorporated into anionic waterborne polyurethane (AWPU) and cationic waterborne polyurethane (CWPU) following three incorporation ways (post-, in-situ and pre- methods). Subsequently, films were obtained by solvent-casting and their thermal, mechanical, contact angle and antibacterial properties were systematic studied. The results shown that owing to the strong electronic attraction between PHMG and AWPU, the stable PHMG modified AWPU (PAWPU) dispersions were obtained by pre-method only. However, PAWPU films has no antibacterial activity. In addition, the stable PHMG modified CWPU (PCWPU) dispersions were obtained by pre-method and in-situ -method. Unlike PAWPU films, PCWPU films exhibited excellent antibacterial activity, the antibacterial efficiency of PCWPU containing 2 wt% PHMG against E. coli is 98.4 % after 1 h incubation. Simultaneously, PHMG not leached from PCWPU films. [ABSTRACT FROM AUTHOR]