聚对苯二甲酸-2,5-呋喃二甲酸乙二醇无规共聚酯的合成与表征

以对苯二甲酸、2,5-呋喃二甲酸(FDCA)和乙二醇为原料,钛酸四丁酯为催化剂,采用直接酯化法,通过改变对苯二甲酸与2,5-呋喃二甲酸摩尔比合成了一系列高分子量线性聚对苯二甲酸-2,5-呋喃二甲酸乙二醇无规共聚酯(PEFT).运用1H-NMR和13C-NMR表征并确立了共聚酯的结构,XRD结果显示该系列共聚酯在原生态状态下均为无定形聚集态结构,DSC结果表明该系列共聚酯只有一个玻璃化转变温度(73.3～84.2℃),介于PET和PEF之间,随着PEF含量的增加而增大.TGA结果显示该系列聚酯具有良好的热稳定性,起始热分解温度高于390℃,介于PET和PEF之间.拉伸测试结果表明共聚酯的组成对其力学性能有影响,其中PEFT-10,PEFT-70和PEFT-90的力学性能较好,优于PET.     

聚2,5-呋喃二甲酸乙二醇酯的合成与表征

以2,5-呋喃二甲酸和乙二醇为原料,草酸亚锡为催化剂,通过直接酯化法合成了线性高分子量聚2,5-呋喃二甲酸乙二醇酯(PEF).运用红外光谱(FTIR)和核磁共振氢谱(1H-NMR)表征了该聚酯的结构;由乌氏黏度计法和凝胶渗透色谱(GPC)建立了该聚酯在一种混合溶剂体系中特性黏数和重均分子量的关系:[η]=2.82×10-6Mw0.99dL/g,25℃,苯酚-四氯乙烷(1∶1,W/W);示差扫描量热法(DSC)和热失重分析(TGA)测定了该聚酯的热转变性能,结果表明该聚酯玻璃化转变温度为84℃,熔点为211℃,起始热分解温度高于370℃,具有良好的热稳定性;运用旋转流变仪研究了PEF的流变性能,结果表明,PEF熔体属于假塑性流体,随相对分子量的减小和温度升高,其非牛顿指数增大,在高于PEF熔点20～40℃,剪切速率为2.17×10-2～1.14×102s-1时,PEF的非牛顿指数为0.85左右.     

聚2,5-呋喃二甲酸乙二醇酯/聚丁二酸丁二醇酯共混物的制备与表征

通过熔融共混制备了聚2,5-呋喃二甲酸乙二醇酯(PEF)/聚丁二酸丁二醇酯(PBS)共混物,探究了制备PEF/PBS共混物的影响因素,考察了共混温度、共混时间、螺杆转速、共混比例对PEF/PBS共混物力学性能的影响因素,并用示差扫描量热仪、热失重、扫描电子显微镜等技术手段对其热性能和相容性进行了表征。 结果表明,当PBS的含量为15%、共混温度为230 ℃,共混时间为90 s、螺杆转速为150 r/min时,为最佳共混制备条件,此时相容性最好,热性能良好,冲击强度和拉伸强度最大,冲击强度相对纯PEF提高了6倍,拉伸强度提高了近20%,从而大幅提高了PEF的冲击强度,有效地增强了PEF的抗冲击韧性。 这些工作为这一生物基聚酯材料的应用提供了可能。     

聚酯-聚酯多嵌段共聚物的合成及其动态力学性能

聚酯-聚醚多嵌段共聚物的动态力学性能谱上有两个T_8,不宜做阻尼材料。本文报道聚对苯二甲酸乙二醇酯(PET)-端羟基聚己二酸乙二醇酯(PEA)共聚物(简称嵌段共聚酯),比聚醚-聚酯多嵌段共聚物有更好的相容性。我们研究了PEA的分子量,间苯二甲酸的用量对嵌段共聚酯的结晶度,以及结晶度对嵌段共聚酯的动态力学性能的影响。     

直接酯化法合成聚2,5-呋喃二甲酸乙二酯

以2,5-呋喃二甲酸(FDCA)和乙二醇(EG)为原料,草酸亚锡为催化剂,采用直接酯化法制备了聚2,5-呋喃二甲酸乙二酯(PEF)。考察了酯化反应、酯化产物、缩聚反应及缩聚产物的影响因素,结果表明,草酸亚锡在该体系中既可催化酯化反应又可催化缩聚反应,当n(FDCA)∶n(EG)=1∶1.6、草酸亚锡摩尔分数为0.1%、酯化温度为210℃、缩聚温度为240℃、缩聚反应时间为480 min、磷酸三甲酯摩尔分数为0.03%时,酯化程度最高(酯化产物的酸值在94%以上),缩聚产物相对分子量最高(比浓粘度达到1.29 dL/g),端羧基含量最低(34.3 mol/t);采用FTIR和1H NMR对目标产物的结构进行了表征。     

运用1H-NMR和13C-NMR研究聚对苯二甲酸-2,5-呋喃二甲酸乙二醇共聚酯（PEFT）的序列结构

采用直接酯化法,通过改变对苯二甲酸(PTA)与2,5-呋喃二甲酸(FDCA)的摩尔比,制备了一系列聚对苯二甲酸-2,5-呋喃二甲酸乙二醇共聚酯(PEFT)。运用1H-NMR和13C-NMR测试手段研究PEFT共聚酯的链结构。通过观察PEFT共聚酯链上乙二醇单元中氢原子和碳原子的化学位移及相应的4种信号的强度变化,计算出共聚酯的数均序列长度(L),无规度值(B)和共聚物的组成。通过Yamadera和Murano公式计算所得共聚酯无规度值B均接近于1,说明PEFT共聚酯为无规共聚物;PEF-block-PET嵌段共聚物B为0.577,PEF-blend-PET共混物的B为0;差示扫描量热仪(DSC)测试结果表明,0PEFT共聚酯均有一个玻璃化温度,进一步说明了PEFT共聚酯为无规共聚物。其中PTA∶FDCA的摩尔比为1∶1时,即PEFT-50,B值最大,基于1H-NMR谱图计算得B=1.012,13C-NMR谱图计算得B=1.028。上述结果表明,2,5-呋喃二甲酸与对苯二甲酸在与乙二醇的亲核取代反应中活性相近。     

聚2,5-呋喃二甲酸1,8-辛二酯的聚合反应

以可再生资源2,5-呋喃二甲酸(FDCA)和1,8-辛二醇(1,8-ODO)为原料,钛酸四丁酯为催化剂,采用直接酯化法制得聚2,5-呋喃二甲酸1,8-辛二酯(1,8-POF)。 考察了原料配比、催化剂用量、酯化温度、缩聚温度及缩聚时间对聚合反应的影响,结果表明,当n(FDCA)∶n(1,8-ODO)=1∶1.2,钛酸四丁酯摩尔分数为0.3%,酯化温度为240 ℃,缩聚温度为260 ℃,缩聚时间为300 min时,缩聚产物的比浓粘度最高（2.1 dL/g）,端羧基含量最低（5.8 mol/t）。 与乙二醇相比,采用1,8-辛二醇为单体降低了酸醇的摩尔比,减少了醇的消耗,同时得到了较高分子量的聚合物。 气质联用仪对酯化馏出液和缩聚产物真空抽出物进行了分析,结果表明,酯化馏出液的主要成分是水,并含有少量的1,8-ODO;缩聚产物真空抽出物的组成为环己酮（56%）、顺式-3-辛烯醇（18%）、4-甲基-3-戊烯-2-酮（17%）和4-羟基-4-甲基-2-戊酮（9%）。     

聚乙二醇对苯二甲酸酯-b-聚对苯二甲酸丁二醇酯多嵌段共聚物内部贯通多孔支架的制备方法

以天然或合成的可生物降解材料制备细胞外基质支架是组织工程所涉及到的关键问题之一.常用的制备方法由于涉及到有机溶剂的使用、较高的加工温度以及致孔剂的残余问题,对于活性物质的引入均带来不利影响,相关的改进工作(如不使用有机溶剂和消除残余致孔剂等)尽管也获得了具有良好孔结构的支架,但却使制备过程更趋复杂.     

聚2,5-呋喃二甲酸乙二醇酯/纳米二氧化钛/硅藻土复合材料的制备和表征北大核心CSCD

以2,5-呋喃二甲酸二甲酯(DMFD)、乙二醇(EG)为原料,原位添加扩链剂均苯四甲酸二酐(PMDA)、纳米二氧化钛(TiO_(2))、硅藻土(DE),以钛酸四丁酯为催化剂,采用酯交换-熔融缩聚法制备聚2,5-呋喃二甲酸乙二醇酯(PEF)/TiO_(2)/DE复合材料。通过核磁共振波谱仪(NMR)、傅里叶变换衰减全反射红外光谱仪(ATR-FTIR)、X射线衍射仪(XRD)和热重分析仪(TGA)等技术手段对其结构、热学性能、力学性能、气体渗透性能及紫外屏蔽性能进行表征。结果表明,PEF/TiO_(2)/DE复合材料被成功制备,且TiO_(2)及DE均为物理掺杂。DE粒子在PEF/TiO_(2)/DE复合材料内部分散良好。所有聚酯粉末为无定形聚集态结构。与PEF相比,PEF/TiO_(2)/DE复合材料的5%质量损失温度(Td,5%)、分解速率最快温度(Tdmax)分别提升12.1℃和8.4℃。PEF/TiO_(2)/DE复合材料的拉伸模量及抗冲击强度最高分别达到2657 MPa和3.2×10^(4)J/m^(2)。纳米TiO_(2)和DE的引入调控了PEF/TiO_(2)/DE复合材料对CO_(2)、O_(2)的渗透性,CO_(2)屏障改善系数(BIF_(CO_(2)))由PEF/TiO_(2)的3.02变为1.37~4.64,O_(2)屏障改善系数(BIFO_(2))由PEF/TiO_(2)的1.36变为0.7~2.07;此外,纳米TiO_(2)的加入赋予PEF良好的紫外屏蔽性能:PEF/TiO_(2)复合材料的紫外屏蔽率由PEF的45.38%提高至83.85%,提高了85%,PEF/TiO_(2)/DE复合材料的紫外屏蔽性能均大于84%。     

嵌段共聚酯的合成研究

采用直接酯化法合成了一系列含间苯二甲酸的PEIT－PEG嵌段共聚酯,研究了聚合时间,聚合效率及聚酯的特性粘度与产物中间苯二甲酸含量及共聚酯分子量的关系,得出适于纺丝工艺及工业化生产的共聚酯分子量和间苯二甲酸的含量。     

An evoluted bio-based 2,5-furandicarboxylate copolyester fiber from poly(ethylene terephthalate)

A series of bio-based poly(ethylene terephthalate-co-ethylene 2,5-furandicarboxylate) (PEFT) fibers was prepared via the industrially feasible melt-spinning and hot-drawing process. The effect of 2,5-furandicarboxylic acid (FDCA) content on the fibers properties was studied using differential scanning calorimetry, wide-angle X-ray diffraction, sound velocity, tensile, and boiling water shrinkage tests. It was found that the PEFT fibers showed comparable or superior tenacity to the PET fibers under the same conditions, especially the PEFT-4 fibers exhibited the highest tenacity (2.3, 2.9 cN/dtex for the drawn PET and PEFT-4 fibers prepared at the same take-up speed of 2500 m/min and a fixed draw ratio of 1.6). Moreover, the boiling water shrinkage of the PEFT fibers was quite close to that of the PET fibers under the same conditions, showing that the PEFT fibers were comparable to the PET fibers in heat resistance. The results indicated that the bio-based PEFT fibers would be a feasible alternative for the PET fibers, in terms of sustainability, processability, and mechanical properties. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 320–329     

甲氧基聚乙二醇-b-聚L-半胱氨酸两亲性嵌段共聚物的合成与表征

首先以聚乙二醇单甲醚(mPEG-OH)为单体,采用经典的盖布瑞尔伯胺合成法合成了端氨基聚乙二醇单甲醚(mPEG-NH_2);然后以mPEG-NH_2为引发剂,S-苄基L-半胱氨酸N-羧酸内酸酐(BCys-NCA)为原料,通过N-羧酸内酸酐(NCA)开环聚合反应和液氨/钠处理脱除侧链上的保护基团,合成了两亲性嵌段共聚物甲氧基聚乙二醇-b-聚L-半胱氨酸(mPEG-b-PCys)。采用傅里叶变换红外光谱、核磁共振氢谱对聚合物的结构和组成进行了表征。结果表明:成功制备了侧链具有还原性巯基的两亲性嵌段共聚物mPEG-b-PCys,并且其聚合度可控性良好。     

Shape Memory Properties in Poly(ethylene oxide)–Poly(ethylene terephthalate) Copolymers

Memory effects of several copolymers of poly(ethylene oxide) (PEO) and poly(ethylene terephthalate) (PET) were illustrated with photos, determined with shrinkage experiments and characterized by the recovery of samples to their original figures. Copolymers of appropriate composition could undertake an approximately full recovery which is tightly related to the annealing temperature at which shrinkage of samples occurs to some extent. Melting and recrystallization of PEO segments may be responsible for the memory effect. The memory properties of samples almost kept unchanged after many fatigue cycles (e.g. 15–20 cycles), which could make these copolymers useful in practical applications as novel shape memory materials. © 1997 John Wiley & Sons, Ltd.     

The Synthesis of Poly(ethylene oxide)-Block-Polybutylacrylate

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Synthesis of AB(BA), ABA and BAB block copolymers of tert-butyl methacrylate (A) and ethylene oxide (B)

Well-defined AB(BA), ABA, and BAB block copolymers of tert-butyl methacrylate (tBMA) (A) and ethylene oxide (EO) (B) have been prepared by sequential living anionic polymerization of the two comonomers, irrespective of their addition order. Diphenyl methyl potassium and naphthalene potassium have been successfully used as mono- and difunctional initiators, respectively. In all cases, molecular weight and composition of the block copolymers can be predicted on the basis of the monomer over initiator molar ratio, and the molecular weight distribution is relatively narrow. Size exclusion chromatography, selective extractions of homopolymers, and ¹H- and ¹³C-NMR spectroscopy support that block copolymerization proceeds without homopolymer formation nor side reactions, e.g., transesterification reactions. The PtBMA blocks have been quantitatively hydrolyzed into polyacid ones with formation of polyacid-b-polyether block copolymers as supported by titration, ¹H-NMR, and IR analysis. © 1992 John Wiley & Sons, Inc.     

四臂星形嵌段共聚物s-PDLLA-b-PEG的合成

季戊四醇与D,L-丙交酯开环聚合制得末端为羟基的四臂星形聚乳酸(s-PDLLA);s-PDLLA与羧基封端的聚乙二醇单甲醚(CT-mPEG)完成酯化反应,合成了以季戊四醇为核,以聚乳酸为内部嵌段、聚乙二醇为外部嵌段的四臂星形聚(D,L-乳酸)-聚乙二醇嵌段共聚物(s-PDLLA-b-PEG),其结构经1H NMR,IR和GPC表征。     

Segmented block copolymers of poly(ethylene glycol) and poly(ethylene terephthalate)

A new series of segmented copolymers were synthesized from poly(ethylene terephthalate) (PET) oligomers and poly(ethylene glycol) (PEG) by a two‐step solution polymerization reaction. PET oligomers were obtained by glycolysis depolymerization. Structural features were defined by infrared and nuclear magnetic resonance (NMR) spectroscopy. The copolymer composition was calculated via ¹H NMR spectroscopy. The content of soft PEG segments was higher than that of hard PET segments. A single glass‐transition temperature was detected for all the synthesized segmented copolymers. This observation was found to be independent of the initial PET‐to‐PEG molar ratio. The molar masses of the copolymers were determined by gel permeation chromatography (GPC). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4448–4457, 2004     

Synthesis and characterization of poly(ethylene glycol) methyl ether endcapped poly(ethylene terephthalate)

Linear and branched poly(ethylene terephthalate) (PET) copolymers with polyethylene glycol) (PEG) methyl ether (700 or 2000 g/mol) end groups were synthesized using conventional melt polymerization. DSC analysis demonstrated that low levels of PEG end groups accelerated PET crystallization. The incorporated PEG end groups also decreased the crystallization temperature of PET dramatically, and copolymers with a high content of PEG (>17.6 wt%) were able to crystallize at room temperature. Rheological analysis demonstrated that the presence of PEG end groups effectively decreased the melt viscosities and facilitated melt processing. XPS and ATR-FTIR revealed that the PEG end groups tended to aggregate on the surface, and the surface of compression molded films containing 34.0 wt% PEG were PEG rich (85 wt% PEG). PEG end-capped PET (34.0 wt% PEG) and PET films were immersed into a fibrinogen solution (0.7 mg/mL BSA) for 72 h to investigate the propensity for protein adhesion. XPS demonstrated that the concentration of nitrogen (1.05%) on the surface of PEG endcapped PET film was statistically lower than PET (7.67%). SEM analysis was consistent with XPS results, and revealed the presence of adsorbed protein on the surface of PET films.