生物可降解聚合物的THz光谱研究

【作者】 张舜拯；

【导师】 王卫宁；

【作者基本信息】 首都师范大学 ， 光学， 2008， 硕士

【摘要】 近年来,随着化学合成塑料造成环境“白色污染”的日趋严重,对生物可降解聚合物的研究引起人们的普遍关注。运用THz时域光谱测试技术对2种结构简单的聚合物(聚乙烯和聚氧化乙烯)和4种生物可降解聚合物(聚β-羟基丁酸酯、聚β-羟基丁酸-co-3-羟基戊酸酯、聚β-羟基丁酸-co-3-羟基己酸酯、左手性聚乳酸)进行了THz光谱测试研究,获得了样品在0.2-2.6THz范围内的吸收系数和折射率,给出了它们在该波段的特征吸收峰,色散关系及色散变化的规律。不同的样品在THz波段有不同的特征吸收峰位,即使是结构很相近的生物可降解聚合物样品其吸收光谱也有显著的差异;在吸收峰对应的频率附近,色散呈反常性质,即样品的折射率随频率增加而减小,而远离吸收峰位处,色散呈正常规律,即折射率随频率增加而增大。根据样品单体结构官能团的位置和类型不同,对样品在实验波段的特征吸收峰进行了归属讨论。同时,本文利用红外光谱技术对样品PHB、PHBV和PHBHHx进行了红外光谱测试。比较两种光谱技术得到的实验结果发现,两种光谱技术在反映分子振动模式上所得的结果是一致的。研究成果,为利用THz光谱技术研究生物可降解聚合物的构象和开展聚合物分子动力学研究提供了基础数据和新方法。更多还原

【Abstract】 In recent years,with the increasing "White Pollution" caused by chemosynthetic polymers people pay their attentions to the research of bio-degradable polymers.The optical characteristics of 2 kinds of elementary polymers and 4 kinds of bio-degradable polymers are detected by THz-TDS,which include Polyethylene Polyethylene oxide Poly-3-hydroxybutyrate Poly-(3-hydroxybutyrate-co-hydroxyvalerate) Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and Poly-L-Lactide.The refractive indices and the dispersion coefficients of those samples are obtained based on the physical model represented by T.D.Dorney and L.D.Duvillaret to abstract the optical parameters of materials in range between 0.2 and 2.6THz.The absorption peaks have the significant difference between the different samples.Comparing the spectrums of absorption and refractive indes of the same sample,the relationship between absorption and dispersion is discussed.When closing to the absorption peak,the refractive index decreases as the increasing of the frequency,and when far away the absorption peak,the refractive index increases as the increasing of the frequency.The characteristic absorption peaks of samples are assigned to their monomer functional groups,according to their monomer structure.In succession,the IR spectrums of PHB PHBV and PHBHHx are detected.Comparing the spectrums of IR and THz, it was found that the two kinds of spectroscopy are consistent in revealing the molecular vibrational mode.This article research results provides the essential data and the new method for using THz-TDS to study the conformation and molecular dynamic of bio-degradable polymer.更多还原