摘要
用熔融缩聚法合成了一系列基于聚对苯二甲酸丁二醇酯(PBT)、聚丁二酸丁二醇酯(PBS)及聚乙二醇(PEG)的嵌段共聚物(PBT co PBS/PEG).1HNMR结构分析显示,软段摩尔百分含量恒为 2 0 %.随组成中PBS含量增加,软段质量百分含量略微升高,硬段PBT平均序列长度由 2 80逐步减至 1 2 3,PBS平均序列长度由 1 2 7逐步增加到4 76,无规度在 1 1附近,两者呈无规分布.受组成及硬段平均序列长度变化影响,材料内部呈微观相分离状态,DSC热分析曲线上可分别观察到软、硬段熔点(Tm,s,Tm,h)及玻璃化转变温度 (Tg,s,Tg,h).硬段熔点及结晶度随PBS含量升高而降低,在 5 0～ 60mol%处达到最小值,则是PBS与PBT二者间形成共晶所致.力学性能测试及水解降解实验表明,将脂肪族聚酯PBS引入PEGT/PBT共聚体系,可赋予高分子链更好的柔韧性及亲水性。
The poly(butylene terephthalate)-co-poly(butylene succinate)-b-poly(ethylene glycol) segmented block Copolymers (PBT-co-PBS/PEG) with PBS molar fraction (M-PBS) varying from 10% to 60 mol% were synthesized by melt polycondensation technique and characterized structurally by means of NMR, DSC, GPC, etc. The analysis on the sequence distribution of two hard segments in the copolymer chain reveals that the average sequence length of hard segment PBT decreased from 2.80 to 1.23, while that of PBS increased from 1.27 to 4.76 with the increase of PBS molar fraction, and the random distribution of the two hard segments was justified for the location of randomness around 1.1. Microphase-separation structure was demonstrated for the appearance of the two glass transition temperature ( T-g,T-s, T-g,T-h) and two melting points ( T-m,T-s, T-m,T-h) in DSC curves of most of the samples. Especially, the co-crystallization between two hard segments might be responsible for the minimum value of the melting point and crystallinity of the hard segments where M-PBS reached 50 similar to 60 mol%. It can be concluded that incorporation of aliphatic moiety PBS in PEGT/PBT copolymer, will impart higher flexibility and hydrophilicity and faster degradation rate to the polymer chain.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2002年第12期2225-2231,共7页
Acta Chimica Sinica
基金
国家 8 63"计划(No.2 0 0 1AA2 160 71)资助项目
