||In the first part of this study, corn starch, poly(butylenes adipate-co-terephthalate)(PBAT), Joncryl ADR-4370S water, urea and glycerol were selected as the basal materials, to investigate the urea , glycerol and ADR additives effect on the mechanical properties. By adding 5.2% urea without adding ADR,we obtained a plastic sample of tensile strength 6.38 ± 0.36 MPa , elongation at break of 36.23 ±11.27 ％ and Young’s modulus of 337.04±11.61 MPa. By adding 5.2% urea with ADR, we obtained a plastic sample of tensile strength of 6.92 ± 0.05 MPa , elongation at break of 27.2 ± 5.4 ％, and Young’s Modulus of 242.7±18.3 MPa.
The second part of this study is a 23 expermental design to find the proper compostion of ADR(A), urea(B) and glycerol(C) ratio for the tensile strength, elongation and Young's modulus of samples. We try to reduce the material costs by reducing biodegradable polyester PBAT and increase the starch content. We found that by adding 1.25% ADR , 4% urea and
4% glycerol , the plastic sample could reach the maximum tensile strength of 5.11 ± 0.43 MPa. By adding 5 % ADR, 8 % urea and 8% glycerol, the maximum elongation of the plastic sample could reach 27.2 ± 2.3 %.
By adding 1.25% ADR , 4 % urea and 4% glycerol, the plastic’s Young’s modulus could increase to 510.1 ± 44.5 MPa. Taking advantage of 23 experimental design of overlay design to study the three factors effect on mechanical properties and influence of costs. According to the results, we found that by adding 1.49 % ADR, 4.11% urea and 4% glycerol the plastic sample costs 168 NT/kg and it could reach tensile strength of 5.02 MPa, elongation 3.7 % and Young’s modulus 497.7 MPa. Comparing 23 experimental design of overlay design with the first part of experimental Run 1 ( the tensile strength is 5.01 ± 0.28 Mpa).We could find the tensile strength is similar , elongation decreased 28% , Young’s modulus increased 58% and costs reduced 12 NT/kg. The results of this study show that in order to reduce costs of polymer samples and maintaining part of mechanical properties .
We could use corn starch to replace the high price of PBAT and also use urea to replace part of glycerol.