Study On Preparation And Performance Of Urushiol-based Natural Coatings Modified With Soybean Protein Isolate/Inorganic Filler

Urushiol based coatings have great potential in the coating market because of its green raw material source and beautiful texture after film formation.However,its widespread use is limited because of its low hardness,low impact resistance and poor adhesion.Therefore,soybean protein isolate and three different inorganic fillers(Calcium Sulfate Whisker,Silicon Carbide,Hydroxyapatite)were used to modify urushiol alone and in combination in this paper,and the performance of the lacquer lacquer film before and after modification were studied,and the modification process were analyzed by infrared spectroscopy(FT-IR),X diffraction experiment(XRD),scanning electron microscopy(SEM)and thermogravimetric(TG),etc.The main results are as follows:(1)Soybean protein isolate can significantly improve the impact resistance and adhesion of the lacquer film.Soy protein isolate can crosslink with urushiol to improve the tightness of the lacquer film after curing,thereby improving the properties of the lacquer lacquer film.When the amount of soybean protein isolate was 3 wt%,the comprehensive performance of the lacquer film was the best.Compared with the control group,the surface drying time was shortened by 40 min,the gloss was increased by 23%,the hardness was increased from H to 2 H,the impact resistance was increased by 10 times,and the adhesion of the lacquer film was increased from the worst grade 5 to grade 1.(2)The metal ions in the inorganic filler can promote the crosslinking of urushiol,so that the structure of the lacquer film is tighter,and the inorganic filler evenly dispersed in the lacquer film can also play a role in dispersion strengthening,so that the performance of the lacquer film can be improved.Among the three inorganic fillers,the comprehensive performance of the lacquer film obtained by calcium sulfate whisker modified urushiol was the best.Compared with the control group,the surface drying time of the lacquer film was shortened by 40 min,the gloss was increased to 140.5 GU,the hardness of the lacquer film was increased from H to 3 H,the impact resistance was increased by 50%,and the adhesion was increased from grade 5 to grade 4.(3)The composite modification of soybean protein isolate and calcium sulfate whiskers can make the lacquer film form a more compact and stable structure,thereby improving the comprehensive performance of the lacquer film.However,due to the steric hindrance of the reaction between soy protein isolate and urushiol,the uniformly dispersed calcium sulfate whisker reduces the impact resistance of the lacquer film compared with the modification of soy protein isolate alone.Compared with the control group,the surface drying time of the lacquer film was shortened by 45 min,the hardness of the pencil increased from H to 4 H,the gloss increased by 23.07%,the impact resistance increased from 10 cm to 40 cm,and the adhesion increased to grade 3.