【摘要】 合成了一系列乙酸稀土盐(乙酸钇,乙酸镧,乙酸钕,乙酸镝),作为单组分催化剂,采用熔融缩聚法催化对苯二甲酸二甲酯、乙二醇和1,6-己二酸的共缩聚反应,制备了芳香族脂肪族共聚酯——聚(对苯二甲酸乙二酯-co-己二酸乙二酯)(PETA).通过1H-NMR,SEC,DSC及力学性能测试表征了聚合物的序列结构,分子量及分布,热性能及机械性能.结果表明,乙酸稀土盐单组分可催化共缩聚反应,效果优良,能够合成高分子量和较窄分子量分布的共聚酯,共聚酯具有较高的拉伸强度和断裂伸长率.更多还原

【Abstract】 Rare earth (Nd,Y,La,Dy) acetates have been synthesized and used as single component catalysts for the polycondensation of dimethyl terephthalate,adipic acid and ethylene glycol first preparing aromatic/aliphatic copolyester are poly(ethylene terephthalate-co-ethylene adipate) (PETA) with high molecular weights.The copolyesters catalyzed by different rare earth acetates were characterized by means of 1H-NMR,DSC,SEC and mechanical testing.The compositions of the coplyesters calculated by the peak integrals of 1H-NMR spectra show that the molar fractions of the copolyester are consistent with the feeding molar ratio of the raw materials.The analysis on the sequence distribution of the two segments in the copolyester chains reveals that the average sequence length of PET and PEA is in the range of 1.92～2.02 ,and the random distribution of the two segments is also validated by the degree of randomness around 1.01. The DSC analysis shows a single glass transition temperature (Tg) of PETA at -1～-4℃ without melting temperature (Tm) suggesting the random structures and thermoplastic elastomeric property.The SEC spectra showed high weight-average molecular weight (Mw) and polydispersities of PETA in the values of 3.24～3.88×104 g/mol and 1.81～1.94,respectively,demonstrated the high effect of the catalysts,but there is no significant difference of the activity between the four rare earth acetates.The copolyesters exhibit good mechanical properties such as high tensile strength (ca.11 MPa) and large breaking elongation (>510%) measured with the re-molten films at room temperature.The tensile strength of the copolyesters has a slight increase with the increasing of molecular weight.更多还原