用~1H-和~(13)C-NMR方法研究聚对苯二甲酸乙二酯/聚一氧基苯甲酸酯共聚酯的序列分布

测定了PET/30PHB和PET/60PHB共聚酯的高分辨~1H和~(13)C谱,并采用INEPT方法和部分弛豫FT技术确定了季碳吸收峰,对NMR谱进行了归属.应用我们先前提出的方法对共聚酯的序列分布进行了表征.结果表明,两种共聚酯的无规度B_q值均小于1,序列分布不象Jackson等认为的那样为完全无规的.此外,文中还指出,某些研究者套用Flory公式判别PET/PHB共聚酯是否为无规的不妥之处.     

用1H-和13C-NMR方法研究聚对苯二甲酸乙二酯/聚一氧基苯甲酸酯共聚酯的序列分布

 测定了PET/30PHB和PET/60PHB共聚酯的高分辨¹H和¹³C谱,并采用INEPT方法和部分弛豫FT技术确定了季碳吸收峰,对NMR谱进行了归属.应用我们先前提出的方法对共聚酯的序列分布进行了表征.结果表明,两种共聚酯的无规度B_q值均小于1,序列分布不象Jackson等认为的那样为完全无规的.此外,文中还指出,某些研究者套用Flory公式判别PET/PHB共聚酯是否为无规的不妥之处.     

对羟基苯甲酸(PHB)聚对苯二甲酸乙二酯(PET)液晶共聚酯和聚对苯二甲酸乙二酯共混物的酯交换表征

在温度280℃附近对含有液晶共聚酯P-Hydroxy Benzoic Acid/Poly(-Ethylene Terephthalate-)PHB/PET和Poly(-Ethylene Terephthalate-)PET的共混样品进行热处理时,发现共混物的熔点随热处理的时间增加而不断降低,热处理温度越高,相同时间内共混物熔点下降程度越大;而具有相同热历史的纯PET样品熔点几乎保持不变.通过NMR方法证实了PHB/PET-TET共混物熔点随热处理时间下降是由于PHB/PET和PET之间发生了酯交换反应.所以可根据共混物的宏观热性质和PHB/PET序列结构变化表征PHB/PET和PET共混物之间的酯交换程度.     

一种新型阻燃抗熔滴共聚酯的合成及表征

双酚A与碳酸乙烯酯反应得到改性单体双(羟乙基)双酚A(BHEEB),BHEEB与对苯二甲酸、乙二醇及阻燃剂[(6-氧代-6H-二苯并[c,e][1,2]氧磷杂己环-6-基)甲基]丁二酸(DDP)通过无规共聚合成了一种新型阻燃共聚酯PBPET.用1H-NMR、ICP-AES对共聚酯的结构进行了表征,用热重分析(TGA)、氧指数(LOI)测定、垂直燃烧测试等对共聚酯的热稳定性、阻燃性和熔滴行为进行了研究.结果表明,BHEEB可以提高共聚酯的热稳定性,含5 mol%BHEEB与4.8 mol%DDP的共聚酯P4.8B5PET,其TGA测试中600℃下氮气氛残炭(wt6R00)可达18.0%.燃烧测试表明,P4.8B5PET的LOI值可达37.0,垂直燃烧达V-0级,并且改性单体BHEEB的引入还能有效地改善聚酯燃烧时的熔滴行为.     

一种支氏液晶共聚酯的合成

在聚对苯二甲酸乙二醇酯与对羟基苯甲酸 (HBA)形成的共聚酯 (PET HBA)分子链中 ,引入具有分形结构的单体———三羟基苯 (TOP) ,以降低其熔点 ,改善加工性能 .考察乙酰化时间、缩聚时间、压力、TOP和HBA加入量对新型分形共聚酯的对数比浓粘度的影响规律 ,以及TOP和HBA加入量对新型分形共聚酯的熔点和液晶清亮点的影响 .TOP的加入能使PET HBA共聚酯的熔点下降 10℃以上 ,而液晶清亮点没有变化 ,拓宽了液晶区域     

热致性液晶共聚酯的拉伸流动行为

采用入口收缩流动的实验方法研究了改性PET/ 80PHB液晶共聚酯LCP80的拉伸流动行为 ,考察了拉伸速率、温度等对其拉伸粘度、Trouton比的影响 .实验结果表明 ,LCP80的入口压降值很大 ,其中由拉伸引起的入口压降是主要的 .在该文实验条件下LCP80均表现出拉伸稀化现象 ,并且Trouton比值都远大于 3 .根据流动中液晶织态结构的变化解释了实验现象 ,并对入口收缩流动的实验数据处理方法作了改进 ,比Beery的方法更为合理 ,也具有更广的适用性 .     

对苯二甲酸乙二醇2-甲氧基-1,3-丙二醇共聚酯的合成与表征

以源自甘油的2-甲氧基-1,3-丙二醇（MPD）代替1,3-丙二醇,采用直接酯化法,合成了一系列不同配比的对苯二甲酸(PTA)乙二醇(EG)2-甲氧基-1,3-丙二醇共聚酯PET-PMT（简称PEMT）,并对其进行表征。 用红外光谱、核磁共振研究了PEMT的结构和化学组成;用GPC测定了不同配比PEMT的相对分子质量与相对分子质量分布;乌氏粘度计测定了其粘度;用DSC分析了其结晶性能。 结果表明,共聚酯PEMT中PMT链段的实际接入量比投料的MPD比例高。 且PEMT的粘度明显高于PET的粘度。 第三单体MPD的引入,使共聚酯PEMT的结晶性能下降。 MPD与PTA的投料摩尔比小于0.4时,共聚酯PEMT的结晶与熔融行为类似于PET。 所合成共聚酯PEMT-40（实际n（PMT）∶n（PET）=24∶76）其质均相对分子质量（Mw）为50 216、特性粘度（η）为0.458 dL/g、玻璃化转变温度（Tg）为68.32 ℃、熔点(Tm)为211.07 ℃。 当MPD与PTA的投料摩尔比大于0.6时,共聚酯为无定形共聚物。     

聚对苯二甲酸二甲酯/聚2,5-呋喃二甲酸二甲酯嵌段聚酯的合成与表征

以生物基单体2,5-呋喃二甲酸、乙二醇为原料合成聚2,5-呋喃二甲酸乙二醇酯(PEF)。采用熔融酯交换法以PEF聚酯部分取代聚对苯二甲酸乙二醇酯(PET),制备了系列PET-b-PEF嵌段共聚酯。通过核磁共振仪(NMR)、差示扫描量热仪(DSC)、热失重仪(TGA)、X射线衍射仪(XRD)等技术手段表征了共聚酯的结构和性能。结果表明,该系列共聚酯的玻璃化转变温度(Tg)在75.8~80.3℃之间,且随着PEF链段质量分数的增加,PET-b-PEF嵌段共聚酯的Tg先降低后升高,结晶度和熔融温度逐渐降低。当PEF链段含量高于15%时,共聚酯没有结晶峰。该系列共聚酯具有良好的热稳定性,起始分解温度在392.2~407.9℃之间,与所制备的PET起始分解温度403.3℃接近。且当共聚酯中PEF链段含量低于15%时,起始分解温度均在407℃左右,优于PET的热稳定性。     

非晶聚对苯二甲酸乙二酯的制备与表征

通过单体酯交换法和聚 2 ,6 萘二甲酸乙二酯 (PEN)与低分子量PET酯交换的方法分别合成了一系列NPA/TPA/EG和IPA/TPA/EG共聚酯 .随着NPA或IPA单元含量的增加 ,等温结晶速度迅速降低 ,共聚物的结晶性降低甚至非晶化 .由NMR分析得知单体酯交换法与聚合物酯交换法得到的共聚酯NPA/TPA/EG序列分布相近 ,链结构都接近完全无规 .由DSC结果分析 ,随共聚单体含量的增加 ,熔点和熔融热降低 ,结晶度也随之降低 .当NPA或IPA含量达到 2 0 %时 ,可以得到非晶的共聚酯 (APET) .本文还对共聚物组成与结晶温度的关系进行了表征     

聚对苯二甲酸乙二酯(PET)/聚对乙酰氧基甲酸(PHB)共聚酯及同类共聚物序列分布表征的数学统计

由聚对苯二甲酸乙二酯(PET)和对-乙酰氧基苯甲酸制得的PET/PHB共聚酯代表了一类序列结构较一般二元共聚物复杂的共聚体系.在揭示了这类共聚物与序列分布有关的诸概率参数中只有一个是独立的之后,定义了参数B_q来描述此类共聚物的无规度.并指出,共聚物B_q=b时的序列分布,可以从一般二元共聚物无规度B=b时的序列结构加以推断.     

液晶嵌段共聚物PET/60PHB-b-PC的合成及结构与性能

采用ＰＥＴ齐聚物的原位乙酰化法通过加入少量乙二醇（ＥＧ）合成了端羟基液晶聚合物ＰＥＴ／６０ＰＨＢ，并将其作为大单体，与双酚Ａ及碳酸二苯酯通过熔融酯交换法，进一步制得了液晶嵌段共聚物ＰＥＴ／６０ＰＨＢ ｂ ＰＣ．研究了合成规律，并借助粘度测定、ＤＳＣ、偏光显微镜、Ｘ 光衍射和红外光谱分析等手段对合成的液晶嵌段共聚物进行了表征．研究表明，当ＰＥＴ齐聚物的ηｉｎｈ＝００５～００７ｄＬ／ｇ，Ａｃ２Ｏ／ＰＨＢ（ｍｏｌ／ｍｏｌ）＝１３，ＥＧ／ＰＥＴ（ｍｏｌ／ｍｏｌ）＝００６时能获得颜色、液晶性、溶解性均很好的端羟基液晶聚合物ＰＥＴ／６０ＰＨＢ，以此液晶聚合物为原料，采用合适的配方与工艺，能获得粘度较高、液晶性较好，并且熔体流动性很好的液晶嵌段共聚物ＰＥＴ／６０ＰＨＢ ｂ ＰＣ．通过偏光显微镜与Ｘ 光衍射观察，证明此嵌段共聚物呈现向列型液晶织构，但其液晶态织构与纯ＰＥＴ／６０ＰＨＢ、ＰＥＴ／６０ＰＨＢ和ＰＣ的混合物明显不同．此外，还初步建立了用红外的分析手段鉴定液晶聚合物ＰＥＴ／６０ＰＨＢ端基的方法．     

Direct polyesterification with thionyl chloride in pyridine improved by a modification of monomer sequences in copolymers

The direct polyesterification with thionyl chloride (SOCl₂) in pyridine was further investigated. Copolycondensations of dicarboxylic acids, bisphenols, and hydroxybenzoic acids were significantly affected by the reaction temperatures and combinations of monomers which could change relative rates of alcoholyses of the activated dicarboxylic acids and the hydroxyacids consequently to vary monomer sequences in the copolymers resulted. The sequences were tried to be varied more directly by stepwise reactions of monomers in copolycondensations of dicarboxylic acids, bisphenols, and p-hydroxybenzoic acid (PHB), as well as PHB and m-hydroxybenzoic acid (MHB). The reactions proceeded smoothly and satisfactorily when carried out by initial reaction of dicarboxylic acids and PHB followed by bisphenols likely to favor sequential to random distributions of monomers. Reverse addition of PHB and bisphenols, and then dicarboxylic acids resulted in rapid precipitation due to some oligomerization of PHB at an earlier stage of reaction, and largely retarded the reaction. This was also the case for the copolycondensation of PHB and MHB. Copolymers of high inherent viscosities with up to 65 mol% PHB could be obtained by initial reaction of MHB followed by PHB.     

Direct polyesterification with thionyl chloride in pyridine improved by a modification of monomer sequences in copolymers

The direct polyesterification with thionyl chloride (SOCl₂) in pyridine was further investigated. Copolycondensations of dicarboxylic acids, bisphenols, and hydroxybenzoic acids were significantly affected by the reaction temperatures and combinations of monomers which could change relative rates of alcoholyses of the activated dicarboxylic acids and the hydroxyacids consequently to vary monomer sequences in the copolymers resulted. The sequences were tried to be varied more directly by stepwise reactions of monomers in copolycondensations of dicarboxylic acids, bisphenols, and p-hydroxybenzoic acid (PHB), as well as PHB and m-hydroxybenzoic acid (MHB). The reactions proceeded smoothly and satisfactorily when carried out by initial reaction of dicarboxylic acids and PHB followed by bisphenols likely to favor sequential to random distributions of monomers. Reverse addition of PHB and bisphenols, and then dicarboxylic acids resulted in rapid precipitation due to some oligomerization of PHB at an earlier stage of reaction, and largely retarded the reaction. This was also the case for the copolycondensation of PHB and MHB. Copolymers of high inherent viscosities with up to 65 mol % PHB could be obtained by initial reaction of MHB followed by PHB.     

Chain structure and thermal behavior of reactive blends of PET/LCP with bis(2-oxazoline)

The sequence structure and thermal behavior of reactive blends of poly(ethylene terephthalate) (PET) with the liquid crystalline copolyester 60 PHB/PET containing 60 mol % of p-hydroxybenzoic acid (PHB) with addition of bis(2-oxazoline) (BOZ) were studied in detail. ¹H NMR results indicate that both the number average sequence length of PET and PHB segments (L _PET and L _PHB) decrease with increasing mixing time and temperature via transesterification between PET and LCP. The transesterification is promoted in the presence of BOZ. As a consequence, the sequence structure and in turn the crystallization both from the glassy and the melt state and the melting behavior are markedly affected.     

嵌段液晶高聚物对聚醚砜 - 聚对苯二甲酸乙二醇酯/聚对羟基苯甲酸共混物的增容作用

嵌段液晶高聚物对聚醚砜 聚对苯二甲酸乙二醇酯／聚对羟基苯甲酸共混物的增容作用张海良张雪飞王霞瑜（湘潭大学化学化工学院湘潭４１１１０５）关键词增容作用，嵌段共聚物，原位复合材料基于热致性液晶高分子（ＴＬＣＰ）的原位复合材料以其高性能及易加工等特点而得...     

动态力学温度谱分析的新方法及其应用 Ⅳ.从动态力学温度谱求两相聚合物的双活化能和应力松弛

提出用两个热流变简单粘弹体的并联体系作为两相聚合物的粘弹模型,将先前的动态力学温度谱分析方法推广到两相聚合物中去.运用这种新方法从动态力学数据求出了PET/70PHB共聚物的双活化能,其中150℃左右的转变活化能为71.9kcal/mol,70℃左右的转变活化能为117.5koal/mol,这一数值与文献上PET/60PHB这个转变的活化能120kcal/mol相接近.文中还计算了共聚物在不同温度下的10s应力松弛模量,所得结果与实测值相吻合.     

Rheological behavior in blends of PET with ionomeric polyester

The rheological behavior and the morphology in blends of polyethylene terephthalate (PET) with ionomeric polyester were investigated over a wide range of different blending ratios. The ionomeric polyester is derived from PET modified through copolycondensation with sulfonate moiety, sodiosulfo isophthalate (Na-SIP), iso-phthalic acid (IPA) and polyethylene glycol (PEG). The results showed that the apparent viscosity and non-Newtonian index of the PET/ionomeric polyester blend system had a nonlinearity change with the change of the blend ratio of PET/ionomeric polyester. The anomaly of the viscous flow activation energy change was found as the content of ionomeric polyester was about 40% (w/w) in the blend system, suggesting the presence of physical cross-linked structure formed by strong polar tangling points and the phase separation owing to poor compatibility between the PET and ionomeric polyester. The morphology and thermal behavior of the blends were observed, respectively, with differential scanning calorimetry (DSC) and atomic force microscopy (AMF).     

Extrusion,fiber formation,and characterization of thermotropic copolyesters

The flow behavior and the effect of the spinning conditions on the fiber properties and structure of poly(ethylene terephthalate) modified with 60 mol% p-hydroxybenzoic acid (PET/60PHB) were investigated. PET and its copolyesters with 28 and 80 mol% PHB were used as control samples. The melt of PET/60PHB at temperatures above 265°C exhibited extremely low viscosity and low flow activation energy. High birefringence, indicating the presence of a mesophase, was observed between 265 and 300°C on a hot-stage polarizing light microscope. The maximum tensile strength and initial modulus, 438 MPa and 37 GPa, respectively, were obtained at 275°C for a 0.69 IV polymer. The fiber strength and modulus were significantly lowered when extrusion was conducted at temperatures below 265°C. The fiber properties could also be improved when a high extrusion rate and/or a high draw down ratio was used. Scanning electron microscopy revealed that the fibers spun at temperatures above 265°C had a well-developed, highly oriented fibrillar structure. The fibers spun at lower temperatures, however, were poorly oriented and nonfibrillar in character. The high orientation and superior mechanical performance achieved at high temperatures were attributed to the presence of the nematic mesophase in the polymer melt.