The Study Of Preparation And Properties Of Flame-retardant Poly (Triethylene Terephthalate) Copolyesters

Poly (trimethylene terephthalate) (PTT) is a new polyester production. With the synthesis technique of 1,3- propanediol improving, especially the succeed in biology route, just make a nicer basic for the quick development of PTT. The application of PTT in the clothing, carpeting, house-textile and other domains becomes more and more broad, for its excellent elastic recover, stain resistance, colorableness and other properties. But PTT fibers is flammable as most of other chemical fibers, and it can bring fire or make fire spread, so it is necessary to study the flame-retardant treatmant on PTT.Flame-retardant poly (triethylene terephthalate) copolyester (FR-PTT) was prepared by the copolymeterisation technics . Terephalic aid (PTA) and 1,3- propanediol (PDO) were used as raw materials, phosphorus-containing flame retardant 2-carboxyethy (phenyl) phosphinic acid (CEPPA) was used as copolymeterisation flame retardant. The addition path of flame retardant and the effect of flame retardant and catalyst for the synthesis process were discussed, and en-sured the best synthesis technics. The structure, thermal properties, flame retardancy, rheological properties, thermal degradation behavior and crystal properties were investigated by fourier transform infrared spectrometry (FTIR), nuclear magnetic resonator (1H-NMR), thermogravim-etric analysis (TGA), differential scanning calorimetry (DSC), limiting oxygen index (LOI), ver-tical burning, scanning electron microscopy (SEM) and capillary rheometer. Kissinger method, Flynn-Wall-Ozawa method and Coast-Redfern method were applied to describe the thermal degradation kinetics of copolyester. While the changed Avrami equation was applied to describe the non-isothermal crystallization kinetics of the copolyester.Flame retardant was ensured to be added at the end of esterification, and its thermal stability was improved throught the preparation of the esterifiable solution (CEPPA-PDO), so that it can fill the synthesis temperture of FR-PTT. With the increasing of the content of the flame retardant , more catalyst was needed to promote polycondensation.The introduction of flame retardant into the main molecule chain decreased the glass transition temperature (Tg) and melting temperature (Tm), increased the crystalline temperature (Tc). The introduction of flame retardant improved the flame retardancy of the copolyesters. When the phosphorus content reached 0.6%, the limit oxy-gen index was 30.6%, the flame-retardant grade reached FV-0. Both of PTT and FR-PTT were Pseudoplastic fluid, and non-Newtonian index increased with the increasing of the content of the flame retardant, and the textile temperature should turn down lower than that of PTT. The introduction of flame-retardant monomer decreased the intial degradation temperature of FR-PTT, but increased the temperature under the max thermal degradationt rate. The result of thermal degradation kinetics of PTT and FR-PTT indicated that the thermal degradation activa-tion energy of FR-PTT was lower than that of PTT. Both of the thermal degradation process were divided into four segments. S9 fuction was ensure to be the thermal degradation reaction fuction, and ensured the thermal degradation mechanism of PTT and FR-PTT were both phase-side reaction mechanism. The thermal degradation kinetics equation showed that, with the increasing of phosohorus, the thermal degradation reaction rate decreased.The presence of flame-retardant monomer made crystallization temperature and crystalliza-tion enthalpy of FR-PTT decrease, and crystallizability declined. The result of non-isothermal crystallization kinetics of PTT and FR-PTT showed that, the Avrami index (n) of PTT was found to between 3 and 4,and that of FR-PTT was found to between 2 and 3.