Studies Of The Modified Co-PET With 1, 4-cyclohexanedimethanol And Its Fibers

PETG fiber is an important new kind of modified polyester fibers.Compared to common PET fibers,it can bear high temperature and doesn't produce pillings.It has good elasticity and dying properties.It can be widedly used in clothes and industries.The modified co-polyester PETG and the industry of fibers is a problem which need to be solved radically in polyester fiber industry.The major contents of the article as follows:1.Using interval polymerization device and CHDM from home and abroad,we studied the polymerization technology in which the ethylene which was replaced in all or in part by 1,4-cyclohexanedimethanol react with terephthalic acid to form modified co-polyester.The influence of the factors to the process of polymerization such as different kind catalyst,different amount of catalyst, different amount of assistant catalyst and reacting temperature was discussed.The fit polymerization method was found.The PETG polymer which contained different CHDM and isomer were obtained.It was the first time that we applied the Ti/Si catalyst to the CHDM co-polyesters polymerization at home and abroad.The research indicated that Sb and Ti catalyst could meet the needs of polymerization.Considering some factors of price and the color of polymer,we selected stibium acetate as the polycondensation catalyst of the CHDM modified co-polyesters.The amount of Sb was 90 ppm,thetemperature ranging from 275 to 280 °C was suitable.At the same time,the color of the polymer can be improved by adding 50 ppm Zn as an assistant catalyst.2.Tlie frameworks and properties of the modiiled co-polyesiers and its fibers were studied in a large scale through many advanced methods,such as FTIR,NMR,DTA,DSC and DMA.Particularlly.we discussed the influence of different amount of CHDM and the ratio of isomer to the thermal behavior,crystallization behavior,framework of assembling state,rheological property of the fluid,mechanical property of the fiber and dying property of PETGThe kinetic equation of non-isothermal crystallization of PETG was erected.The studies indicated that the crystallization property of PETG became worse with the rise of CHDM,but Tg became large and Tm became small.The Tg of polymer could be improved through imporoving the ratio of isomer in CHDM,that was improving its anti-thermal property.The rheological experiment of PETG indicated that its fluid belonged to Herschel-Bulkley fluid.The elasticity and dying property of PETG fiber were higher than common PET fiber. The fiber could be deeply dyed with dispersing dyes under the common pressure even if the mole fraction of CHDM was only 6%.3.The conditions of drying,spinning and elongation of PETG fiber were discussed.The suitable technology parameter of POY spinning and elongation was obtained and various kind of PETG fibers wereobtained.The studies showed that the demand of spinning could be met by using vacuum-rotating drum-drying machine at the temperature of 140 °C and the time of drying was no less than lOh.A good spinning property was obtained ai the extruding temperature of 2 75 to 280 C and the high spinning velocity was met.The eligible PETG fiber could prepared at 90 "C of hot-plate temperature, 150 °C of hot-board temperature,630 m/min of elongation velocity,1.9 to 2.0 multiple of elongation multiples.The study filled up the blankness of this field in our country.It has important values not only in theory but also in practice.The industry of the modified co-polyester and its fibers will bring a new developing chance to the polyester industry.