Study On The Structure And Properties Of PTT/PETG Blends And The Blended Fibre

Polytrimethylene terephthalate（PTT） is a new kind of polyester with perfect elastic recovery. It is able to be widely used for its successful industrialization.Poly（ethylene-co-cyclohexane1 ,4-dimethanolterephalate）（PETG） is a kind of copolymer with good thermal stability and processing behaviour. The different content of PTT and PETG where blended, in this article, not only the properties of PTT/PETG blends, but also the structure and properties of the blended fibre were studied.At the first, by theory analysis and using DSC, SEM, the compatibility of PTT/PETG blends was studied. It was found that the PTT/PETG blends were thermodynamics compatible blends. And, the blends were compatible in the amorphous area and incompatible in the crystalline area. With the time of blending increasing, the compatibility of the PTT/PETG blends increased.The thermal ability and thermal stability of PTT/PETG blends were also investigated by DSC and TGA test. It was found that the T_g（glass temperature） and T_mc（crystallization temperature within the process of decreasing temperature） were increased with the content of PETG increasing. The thermal stability of the blend system was strengthened compare to The thermal stability of pure PTT.The non-isothermal crystallization dynamics of PTT/PETG blends and crystalline behaviour were also studied by DSC test and Polarizing microscope with hot stage. It was found that to each blended sample, the value of T_mp（the temperature corresponding to the melting peak） and the half-time of crystallization(t_1/2) decreased with the cooling rate increasing. That means the crystalline rate of the system increased with the increasing of the cooling rate. It was also observed that the spheralite size was smaller and closer with the content of PETG increasing from Polarizing microscope with hot stage.The experiments indicated that the spinnability and drawability of PTT/PETG blends were well, and the mechanical properties of the blended fibre were also favourable. The orientation and sonic modulus of blended fibre were increased with the increasing content of PETG. The elastic recovery of fibre was invariable with the content of PETG increasing in some range, but it was decreased with more content of PETG compare to the PTT fibre.