PEG分子量对PET-PEG共聚物结晶性能的影响

EFFECT OF MOLECULAR WEIGHT OF POLYETHYLENE GLYCOL ON CRYSTALLIZATION RATE OF PETTEG COPOLYESTER

通过共缩聚反应合成了不同ＰＥＧ分子量的ＰＥＴ－ＰＥＧ共聚物，其中ＰＥＧ含量占７％（相对于ＤＭＴ质量比），以ＤＳＣ、解偏振光法测定了共聚物的结晶性能和结晶速度。结果表明ＰＥＧ的引入能有效地增加分子链柔性，改善结晶性能，尤其ＰＥＧ分子量为４０００时，结晶速度得以大大提高，温度为１１０℃时，ＰＥＴ－ＰＥＧ４０００结晶速度仅１ｍｉｎ，电镜分析表明共聚物中的ＰＥＧ分子量提高有助于分子链的有序性提高，从而加速结晶，但同时也会引起分子链缠结，从Ｘ衍射图谱上，可以看出ＰＥＧ在结晶过程中并不进入ＰＥＴ晶格中，它只起到诱导结晶的作用。

The PETPEG copolymers with different PEG molecular weight were synthesized through condensation polymerization. The effect of molecular weight of polyethylene glycol (PEG) on the crystal property of polyethylene terephthate (PETPEG) block copolyester was investigated. The result shows that the polymer chain becomes easy to movement and is in good order as the PEG molecular weight increasing. At the same time, the polymer chain coil becomes serious. Among all the molecular weight of PEG, PETPEG4000 copolymer comprehensive property is the best. So PEG4000 can accelerate crystal rate remarkably and PETPEG4000 copolymer′s crystal rate can attain to 1 s at 110 ℃. In addition, Xray test shows that the crystal structure of PETPEG4000 is the same as that of PET.