聚酯及共聚酯化学组成分析

介绍用甲醇醇解法把聚酯或共聚酯解聚成二元酸二甲酯和二元醇。用差示扫描量热 (DSC)、气相色谱及气相色谱 质谱联用仪对醇解液进行检测分析 ,得到聚酯的化学组成。     

不同间苯含量的共聚酯的合成

研究了 Ti和 Sb催化下不同的间苯含量的共聚酯 (PEIT)的酯化、缩聚反应。结果表明 :随着间苯含量的增加 ,PEIT的酯化反应诱导期缩短 ,酯化温度降低 ,缩聚反应诱导期增长。Ti催化的 PEIT酯化反应速率高于 Sb,而且缩聚反应诱导期比 Sb明显缩短。     

瓶用聚酯第三单体快速过渡方法的研究

应用二级连续理想混合流模型对瓶用聚酯转产中第三单体间苯二甲酸(IPA)的快速过渡法进行模拟研究,并分析得出影响间苯二甲酸过渡速度的因素。     

共聚酯的合成与性能表征

以对苯二甲酸、乙二醇为主要原料,添加共聚单体新戊二醇(NPG)、5-叔丁基间苯二甲酸(tBI),通过熔融缩聚合成了一系列不同组成比例的共聚酯,分析了共聚酯的化学结构与组成、特性黏度、热性能、结晶性能和动态热力学性能。结果表明:随着tBI和NPG含量的增加,共聚酯的熔点降低,结晶能力逐渐减弱;当tBI和NPG物质的量分数总和达到13%及以上时,共聚酯为完全无定形态;tBI单元的加入使共聚酯的玻璃化转变温度升高,弥补了PENT共聚酯玻璃化转变温度低于PET的缺点;共聚酯的初始分解温度高于PET,初始储能模量大于PET,而随着测试温度的升高,共聚酯的柔韧性大于PET材料。     

PBT/PET共聚酯的结晶和熔融

研究了 PBT/PET 共聚酯的球晶形态、等温结晶动力学和热历史对其 DSC 曲线的影响。结果表明:在120℃下,随着共聚酯中 PBT 含量的增加,共聚酯的球晶形态有很大差异,结晶动力学参数 n,k,t_(1/2)~(-1)增大。经不同的温度热处理,共聚酯在 DSC 曲线上出现两个熔融峰。低温峰对应于不完善的结晶,高温峰属于在 DSC 的升温过程中形成的较完善的结晶。     

一种可降解共聚酯的合成及表征

采用对苯二甲酸、1,4-丁二醇和脂肪酸为原料,以直接酯化法缩聚合成了生物可降解的高分子质量脂肪-芳香族共聚酯,并分析表征了此共聚酯的结构、分子质量、力学性能、流变性能及降解性能等。     

PET-PEN共聚酯的合成研究

以2,6-萘二甲酸(NDA)、对苯二甲酸或2,6-萘二甲酸二甲酯(NDC)、对苯二甲酸二甲酯与乙二醇为原料,在2 L聚合反应装置上,采用直接酯化法或酯交换法合成聚对苯二甲酸乙二酯(PET)-聚2,6-萘二甲酸乙二酯(PEN)共聚酯(PETN),探讨了PETN的合成反应条件。结果表明:直接酯化法较酯交换法更加可行易控;直接酯化法反应条件:酸/醇摩尔比为1:(1.3～1.5),NDA摩尔分数(相对于酸的总量)为28%,酯化阶段无需催化剂,酯化反应温度220～250℃,缩聚反应温度280～295℃,合成的PETN特性黏数达0.65～0.85 dL/g;钛系催化剂的催化活性优于锑系催化剂,且添加比例小,添加量为8～50μg/g时,即可得到高特性黏数的PETN。     

瓶用IPA三元共聚酯的工业化开发研究

在解剖国内外样品基础上直接于３万ｔ／ａ的纤维级连续缩聚装置上合成出ＩＰＡ共聚酯切片,然后在１３ｔ／批的转鼓反应器上固态缩聚,增粘成瓶用共聚酯。产品经用户认可,已批量生产近２ｋ     

间苯二甲酸在瓶级聚酯生产中的作用及在线添加方式

瓶级聚酯切片生产中需要加入间苯二甲酸(IPA),简要介绍了IPA的添加对反应过程及产物性能的影响,以及在实际生产中,如何通过在线添加酯化物的方式控制一头两尾不同生产线上瓶级聚酯熔体中IPA的含量。     

核磁共振法测定涤纶长丝含油率

采用核磁共振仪测试涤纶长丝含油率,初步探讨了其在生产过程中的应用。结果表明:与传统洗涤法相比,核磁共振法具有快速、简便、试样不需制备、不称重、不需溶剂的优点,且测试精密度和准确度高。     

Two-dimensional nuclear magnetic resonance of resins

A group of resins was synthesised from a series of phenols and aldehydes, and their structures comprehensively deduced from two-dimensional nuclear magnetic resonance spectroscopy (2-D NMR). Correlation spectroscopy, in particular carbon-proton heteronuclear chemical shift correlation spectroscopy, was shown to be especially incisive in assigning structural features to the NMR signals. The method has permitted fuller structural characterisation of these materials than was heretofore possible, and has identified, inter alia, methylene and methyleneoxy bridges unequivocally: complex substitution patterns in the phenol-derived aromatic rings have also been elucidated. It is demonstrably possible to apply the same techniques to similar complex resin structures, and to utilise these structural insights to determine the mechanistic processes involved in their syntheses.     

红外和核磁共振法鉴定聚醚型聚酯的组成结构

利用红外吸收光谱及核磁共振波谱仪的一维和二维技术对一种未知聚合物试样进行鉴定。由核磁共振二维技术分析得出聚醚酯的序列结构及其分布。结果表明:该未知聚合物试样为聚醚酯弹性体,由对苯二甲酸、间苯二甲酸、新戊二醇、乙二醇、聚四氢呋喃醚共聚而成。     

Elaidic acid in rat liver identified by gas chromatography and nuclear magnetic resonance spectroscopy

Fatty acid composition has been commonly determined by gas chromatography (GC). In the most commonly used methods, the lipids must be converted into methyl esters or other derivatives of the fatty acids before being analyzed by GC. Nuclear magnetic resonance (NMR) spectroscopy has become one of the most promising methods to determine organic structures, providing useful data for analyzing the fatty acid composition of edible vegetable oils. The major advantage of NMR is that identification of each fatty acid is carried out by evaluation of particular signals. We report in this work the fatty acid profile of rat liver after consumption of diets containing different concentrations of partially hydrogenated vegetable fat. The fatty acid composition was identified by GC, and trans fatty acids were also identified by ¹³C NMR spectroscopy. The results obtained by the ¹³C NMR method were close enough to those obtained by conventional GC.     

定量核磁共振法研究进展

核磁共振法广泛应用于有机化合物的定性分析,但是它在化合物纯度定值、含量测定中也具有很重要的作用,分为一维谱(1H、13C、14N、15N、19F、31PNMR)、二维谱(J-分辨、1H-1H、1H-13C、DOSY)、液相色谱-核磁共振联用法(LC-NMR)、固体NMR等NMR类型。其中,1H谱最常用,其他一维谱对不同化合物各有其优势。二维核磁共振法对于在一维谱图中信号严重重叠的复杂样品的定量分析非常重要。LC-NMR联用技术将高效的分离手段与NMR联用,可以获得复杂样品的信息。介绍了各类定量核磁共振法在各领域的研究进展。     

Enzyme-catalyzed polymerization of 8-hydroxyquinoline-5-sulfonate by in situ nuclear magnetic resonance spectroscopy

In this report, we describe the use of in situ NMR spectroscopy to elucidate the mechanism of horseradish peroxidase-catalyzed oxidative free-radical coupling of phenols. We demonstrate the potential of the technique for the polymerization of 8-hydroxyquinoline-5-sulfonate (HQS). Based on the structural changes, we establish the involvement of ortho- and para-position protons (to the hydroxyl group) in the oxidative free-radical coupling polymerization with their relative preferences. For example, in HQS, we establish that the positions 2, 4, and 7 are involved in the chemical bonding with the order of preference being 7 ≥ 2 > 4. Analyses of ¹³C-NMR data suggest the formation of C—C- and C—O—C-type coupling bonds during enzymatic polymerization. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1257–1264, 1998     

Investigations of polymer chains in oriented fluid phases with deuterium nuclear magnetic resonance

Deuterium nuclear magnetic resonance (D n.m.r.) is a potentially powerful technique for exploring molecular structural and dynamical properties of polymer chains in bulk fluids and concentrated solutions. A variety of systems can be investigated (the solid state, elastomeric networks, sheared polymer fluids, chain solutes in liquid crystal solvents, and polymeric liquid crystals), over a wide range of dimensions (local chain properties, rotational isomeric state parameters, behaviour between network junctions or entanglements, evolution of tube distributions, and domain sizes of homogeneous chain alignment). A coarse comparison of low molar mass liquid crystals with condensed phases of entangled polymer fluids and elastomeric networks illustrates the key features of the D n.m.r. technique and establishes a common framework for interpreting experiments.     

C nuclear magnetic resonance spectral analysis of stereosequences in ethylene-propylene copolymer

A number of split peaks dependent on both comonomer sequences and stereosequences were observed in the ¹³C nuclear magnetic resonance (n.m.r.) spectrum of ethylene-propylene (E-P) copolymer. The ¹³C chemical shifts of methylene carbon in stereoisomers of the respective hexad comonomer sequences were predicted by a chemical-shift calculation using the gamma effect on ¹³C chemical shifts and Mark's rotational isomeric state model for E-P copolymer. Assignments of the split peaks that arise from different hexad stereosequences were given by comparison between the observed and calculated chemical shifts. Reference was made to the hexad assignments of comonomer-sequence-dependent peak splittings determined in our previous calculation of ¹³C n.m.r. chemical shifts of stereoregular E-P copolymers. The tacticities were estimated for successive (not separated by ethylene units) propylene units in the hexad sequences.     

Quantitative assessment of alkyl chain branching in alcohol-based surfactants by nuclear magnetic resonance

Surfactants with branched hydrophobes have gained considerable interest, since these can be used in formulations for laundry cleaning at a wide range of conditions. The claims range from improved dissolution rate to hardness tolerance and stain removing efficacy. In contrast to the historically known heavily branched surfactants, novel branched surfactants are less compromised by increased biodegradability. These properties find their basis in the structural characteristics of the hydrophobe, such as number, position, and type of alkyl chain branches. Our current understanding of structure-property relations, however, is hampered by the lack of generic methodology needed to obtain structural data on hydrophobe branching. A nuclear magnetic resonance (NMR) approach was developed by which we could obtain a comprehensive set of quantitative hydrophobe branching parameters in alcoholbased surfactants. The ¹³C and ¹H NMR spin systems of hydrophobe branched species were assigned by means of twodimensional NMR techniques. These assignments allowed the quantitative assessment of these branched species by straight-forward signal integration in the ¹H and ¹³C NMR spectra. The quantified NMR data can be used to understand product performance and the biodegradation of surfactants with branched hydrophobes.     

用固体核磁技术分析PE 100管材料的抗熔垂性

用固体核磁技术分析了2种具有不同抗熔垂性能的聚乙烯管材料的凝聚态结构与流变性能。管材树脂的抗熔垂性能与其核磁迟豫特性紧密相关,好的抗熔垂性能对应更长的纵向迟豫时间。抗熔垂性能好的双峰管材料的重均分子量更高,高相对分子质量部分的含量更多。