Modified Acrylic Emulsion From Waste PET And Its Application

PET polyester material has been widely used as packaging material because of its excellent properties such as high-strenghth,easy processing,high transparency,harmless,etc.With the development of the food industry,the amount of PET is increasing.Allthough it is non-toxic,the PET waste will cause enormous environment pressure and wasting of resources after discharged into the environment.In this paper,waste PET polyester material as the research object,was degraded by ethylene glycol,resulting excellent and modified acrylic emulsion through synthesis of aqueous polyurethane and functional monomers using alcoholysis products.Furthermore,it explored the experiment of modified grout using modified acrylic emulsion,obtaining better polymer-modified cement.Waste PET was depolymerized by ethylene glycol(EG)with zinc acetate as catalyst,then aqueous polyurethane prepolymer(WPU)synthesized by PET degradation product(BHET)and other materials.Whereafter,a series of aqueous polyurethane modified styrene-acrylate emulsionwere prepared through polymerization method using aqueous polyurethane prepolymer,styrene(St)and butyl acrylate(BA).The optimum conditions for the degradation process were studied.The results show that the modified styrene-acrylate emulsion exhibited the best performance when the ratio of n(NCO)and n(OH)was 1.2?1.4,the mass ratio of BA,St and WPU was 2.5:2.5:5,blocking agent(HEA)was 30%.The structure of glycolyzed product was characterized by hydroxyl value determination,Fourier transforms infrared spectroscopy and Nuclear magnetic resonance and the structure and thermal stability of the hybrid emulsion were characterized by Fourier transforms infrared spectroscopy and Thermogravimetric analysis.Functional monomer was synthesized by using acrylic acid and PET degradation product as raw material,p-toluenesulfonic acid as the catalyst,4A molecular sieve as the water absorbent,and then using Nuclear magnetic resonance to determine the structure of the functional monomer.Styrene,butyl acrylate,methacrylate and functional phosphate ester were used as the reaction monomers to prepare modified emulsion through pre-emulsification technology and semi-continuous seed emulsion polymerization.The influences of the ratio of soft monomer and hard monomer,the amount of initiator,the amount of emulsifier,temperature on the emulsion performance,pH on the emulsion performance and the amount of functional monomer were discussed.The structure of the polymer emulsion was characterized using Fourier transforms infrared spectroscopy.The results showed that the better integrated performance of emulsion could be prepared when the proportion of hard monomers and soft monomers was 1:1,the addition amount of initiator was 0.6%of the total monomer,the addition amount of emulsifier was 3.0%of the total monomer,polymerization temperature was 80? polymerization pH was 5?6 and functional monomer was 25%.The cement was modified by using improved acrylic emulsion with functional monomer.The influence of polymer on cement standard consistency water and setting time were investigated.The effect of modified emulsion modified cement slurry consistency,setting retarding effect,water retaining performance,anti-permeability and mechanical properties of modified cement slurry were studied.The results showed:modified emulsion could significantly reduce the standard consistency water with a water-reducing function,that was to say,it had the property of water-reducing,when the polymer content and the water reduction rate were 10.0%and 36%,respectively.In addition,modified emulsion for the cement initial setting time,final setting time had an impact,with the increase of polymer parameters,cement initial setting time and final setting time has slowed.When the modified emulsion content was 7.5%,the cement water retaining performance,anti-permeability and mechanical properties were better.