阳离子染料可染聚对苯二甲酸丙二酯共聚酯的合成及结晶性能的研究

SYNTHESIS AND CRYTALLIZATION PROPERTIES OF CATIONIC DYEABLE POLY(TRIMETHYLENE TEREPHTHALATE) COPOLYESTERS

通过直接酯化-缩聚工艺,在聚对苯二甲酸丙二酯(PTT)聚合的酯化过程中加入第三组分间苯二甲酸丙二酯-5-磺酸钠(SIPP),在缩聚过程中加入第四组分聚1,6-己二酸-1,4-丁二醇酯(PBA)或聚乙二醇(PEG)合成了一系列不同的阳离子染料可染PTT,采用氢核磁共振波谱(1H-NMR)、差示扫描量热仪(DSC)和热重分析(TG)表征了产物的结构和性能.与常规PTT相比,经SIPP、PBA或PEG改性后的阳离子染料可染PTT热降解性能影响不大.利用差示扫描量热仪(DSC)进一步研究了PTT及改性后阳离子染料可染PTT的非等温结晶性能,结果表明PTT的Avrami指数n在4.24～4.50之间,表明PTT的非等温结晶成核受均相成核和异相成核的双重影响,结晶比较复杂;PTT经SIPP、PBA和PEG改性后的Avrami指数n在1.72～2.64之间,推测它的成核机理主要是异相成核,并且结晶活化能高于常规PTT,说明阳离子染料可染PTT的结晶对温度比较敏感,因此在纺丝过程中控制温度至关重要。

The third component of 5-sulfoisophthalic acid dihydroxy propyl ester sodium salt（SIPP） and the fourth component of poly（butylene adipate）（PBA） or polyethylene glycol（PEG） were added respectively in the process of esterification and polycondensation for the polymerization of 1,3-propanediol（or trimethylene glycol） and terephthalic acid.Three kinds of cationic dyeable poly（trimethylene terephtalate） copolyesters（PTTs） were synthesized by direct esterification-polycondensation process,and were characterized by differential scanning calorimetry（DSC）,1H-nuclear magnetic resonance（1H-NMR） and thermogravimetric analysis（TGA）,respectively.Compared to PTT,the thermal degradation properties for PTTs modified by SIPP,PBA and PEG almost kept invariant.DSC was used to further investigate the nonisothermal crystallization properties of PTT and the cationic dyeable PTTs,and the experimental results indicated that the Avrami exponents for PTT were from 4.24 to 4.50,suggesting that nonisothermal crystallization mechanism for PTT was simultaneously controlled by homogeneous and heterogeneous nucleation,and the nonisothermal crystallization for PTT was very complex.The Avrami exponents for PTTs modified by SIPP,PBA and PEG were from 1.72 to 2.64,and it was assumed that the nonisothermal crystallization mechanism for cationic dyeable PTTs was the heterogeneous nucleation.The crystallization activation energy of cationic dyeable PTTs was higher than that of PTT,suggesting that the crystallization was more sensitive to the temperature.Therefore,it was of great importance to control the temperature in spinning process.