A high hydroxyl content waterborne polyester-acrylate emulsion was successfully synthesized in two steps. Firstly, the carboxyl terminated unsaturated polyester was synthesized, then it was reacted as a monomer with acrylate monomer by emulsion polymerization using the semi-continuous seeded method. The effects of the amount of hydroxyethyl methacrylate (HEMA), the ratio of polyester/acrylic, the ratio of soft/hard monomer, and the content of chain transfer agent to the properties of the composite emulsion were investigated. Through a variety of tests, both the emulsion and film properties of the composite emulsion were better than polyacrylate emulsion. The introduction of polyester improved the flexibility and impact resistance of hydroxyl acrylate film, and made the modified resin have advantages of both.Keywords:waterborne coatings;hydroxyl polyacrylate emulsion;polyester modification;seeded semi-continuous emulsion polymerization
Hezhen Pang,Jian Wang,Penglei Guo,Jie Zhang,Weiwei Zhao,Na Wang,Xiaoqing Liu
2,2,4,4-Tetramethyl-1,3-cyclobutanediol (CBDO) modified co-polyesters are expected to replace bisphenol A polycarbonate applications in many fields, and the cis – trans isomerisation of CBDO directly affects the co-polyester properties. However, the separation of cis – trans CBDO isomers and the influence of cis–trans isomer ratio on the performance of co-polyester are poorly investigated at present. In this paper, an efficient method of separating cis – trans CBDO isomers was proposed, and CBDO modified PET co-polyesters (PEBT) with a total CBDO content of about 40 % and a cis -CBDO content of 20–100 % were synthesized by modulating the cis - content. The glass transition temperature (T g ) of the co-polyester with 100 % cis -CBDO was as high as 117.8 °C, and the increment in T g of the co-polyester with per mol of cis -CBDO introduced was calculated to be 0.92 °C, which was 2.7 times of the increment of trans -CBDO (0.34 °C). With the increase of cis -CBDO content from 20 % to 100 %, the tensile strength was correspondingly increased from 35.4 MPa to 40.2 MPa, and the elongation at break decreased from 74 % to 18 %, respectively. This paper provides a theoretical basis for the preparation of high-performance CBDO-modified co-polyesters.
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