Modified Poly(Trimethylene Terephthalate)and Its Application In 3D Printing

Poly(trimethylene terephthalate)(PTT),a new member of the thermoplastic polyester,possesses excellent mechanical properties such as high strength,and good stability.However,it is not suitable for FDM because its melting point(?225?)is too high.In this paper,in order to solve the problem,PIA and SA are introduced into PTT to replace prat of PTA,a modified poly(trimethylene terephthalate)(MPTT)containing poly(trimethylene terephthalate-co-isophthalate)(PTTI)and poly(trimethylene terephthalate-co-isophthalate-co-seacate)(PTTIS)were prepared for fused deposition modeling by direct esterification and subsequent polycondensation.The PTTI and PTTIS were characterized by gel permeation chromatography(GPC),1H-NMR and DSC.The tensile strength,elongation at break and flexural strength as well as notched impact strength were measured using a universal electronic tensile machine and an impact strength tester.The effect of the ratio of dibasic acid on the properties of copolyester was investigated.The results showed that the molar ratio of PTA to PIA was nPTA/nPIA=7/3,the performance of PTTI was excellent.On the basis of this,the effect of SA mole fraction(asA = 0-4.8 mol%)on mechanical properties and rheological properties of PTTIS was investigated.The suitable synthesis conditions of PTTIS for 3D printing were obtained.The 3D printing materials which were prepared from PTTIS were tested by a 3D printer to assess their suitability for Fused deposition modeling(FDM).The results showed that the PTTIS(nPTA/nPIA =7/3 containing 1.0-3.8mol%SA)are suitable for FDM.The anisotropy of ultimate tensile strength and elongation at break values for the samples were tested.The results show that when nPTA/npIA= 7/3 and asA = 1-3.8mol%,the obtained PITTS can print three-dimensional solid smoothly on a 3d printer,and its anisotropic properties can meet the practical application requirements.