Preparation of UV-Curable Low Surface Energy Polyurethane Acrylate/Fluorinated Siloxane Resin Hybrid Coating with Enhanced Surface and Abrasion Resistance Properties.

Jianping Zhou,Hongbo Liang,Zhengyue Wang,Hailong Wang,Chunfang Zhu

doi:10.3390/ma13061388

Abstract

Low surface energy coatings have gained considerable attention due to their superior surface hydrophobic properties. However, their abrasion resistance and sustainability of surface hydrophobicity are still not very satisfactory and need to be improved. In this work, a series of utraviolet (UV)-curable fluorosiloxane copolymers were synthesized and used as reactive additives to prepare polyurethane acrylate coatings with low surface energy. The effect of the addition of the fluorinated graft copolymers on the mechanical durability and surface hydrophobicity of the UV-cured hybrid films during the friction-annealing treatment cycles was investigated. The results show that introducing fluorosiloxane additives can greatly enhance surface hydrophobicity of the hybrid film. With addition of 2 wt.% fluorosiloxane copolymers, the water contact angle (WCA) value of the hybrid film was almost tripled compared to that of the pristine PU film, increasing from 58° to 144°. The hybrid film also showed enhanced abrasion resistance and could withstand up to about 60 times of friction under a pressure of 20 kPa. The microstructure formed in the annealed film was found to contribute much to achieve better surface hydrophobicity. The polyurethane acrylate/fluorinated siloxane resin hybrid film prepared in this study exhibits excellent potential for applications in the low surface energy field.

Highlights

Over the past few years, fluoropolymers [1,2,3,4] have attracted much attention due to their many advantages, such as weather resistance, heat resistance, and solvent resistance [5,6]
Dibutyltin dilaurate (DBTDL), N,N-dimethyl benzyl ammonia (DBA), tetradecyl trimethyl ammonium bromide (MTBA), carbon disulfide, 1-dodecanethiol, chloroform, acetone, and sodium hydroxide were all purchased from Xilong Chemical Co., Ltd. (Shantou, China)
A new weak absorption peak appeared at around 912 cm-1 which is attributed to the vibration of the epoxy ring introduced by the Allyl glycidyl ether (AGE) monomer [24,25]

Summary

Introduction

Over the past few years, fluoropolymers [1,2,3,4] have attracted much attention due to their many advantages, such as weather resistance, heat resistance, and solvent resistance [5,6]. As the C-F bonds are strong (bond energy of 485 kJ mol−1 ) and the fluorine atoms exhibit low polarizability and strong electronegativity [7], polymers containing a significant fraction of fluorine atoms usually possess excellent chemical and thermal stability [8]. The fluoroalkyl groups along the molecular chains endow these polymers with unique surface properties, such as adhesion resistance, low friction coefficient, and antifouling properties [9]. Great efforts have been made to develop and optimize fluorinated materials. The relevant research is very extensive, mainly including dielectric performance [10], yellowing resistance, and low volume shrinkage properties of urethane acrylate [11]—the effect of different polymerization methods [12], the influence of perfluoroalkyl chain [13], and the effect of fluorinated siloxane graft copolymer [14].

Methods

Results

Conclusion