PBT/PEG/LA可降解聚醚酯的合成及纺丝研究

采用对苯二甲酸二甲酯(DNT)、1,4-丁二醇(BDO)、聚乙二醇(PEG)和乳酸(LA)合成了聚对苯二甲酸丁二醇酯(PBT)/PEG/LA可降解聚醚酯,通过纺丝制备了PBT/PEG/LA共聚物纤维。结果表明:红外光谱和核磁共振分析所得聚合物为PBT/PEG/LA。PBT/PEG/LA共聚物在50℃真空预干燥5 h,80℃干燥5 h,控制纺丝温度高于聚醚酯熔点15～30℃可顺利纺丝,纤维质量良好。随着拉伸倍数、热定型温度或时间的增加,纤维的断裂强度提高.断裂伸长率下降。LA摩尔分数高,有利于纤维降解,但纤维熔点和断裂强度相应下降。     

聚对苯二甲酸丁二醇酯共聚己二酸丁二醇酯热降解动力学研究

为了研究对比聚对苯二甲酸丁二醇酯共聚己二酸丁二醇酯(PBAT)、聚己二酸丁二醇酯(PBA)以及聚对苯二甲酸丁二醇酯(PBT)的热稳定性,采用热失重(TG)分析法研究了三种树脂的热降解行为.使用Kinssinger法、Flynn-Wall-Ozawa法以及Coats-Redern法对三种树脂的热降解表观活化能以及反应机理...     

基于链段法的PBT聚合反应体系建模及工艺流程模拟

基于链段法定义了对苯二甲酸和1,4-丁二醇聚合生成聚对苯二甲酸丁二醇酯(PBT)的反应体系的各组分和基团,明确了体系中的反应类型有酯化反应、酯交换反应、酯基降解反应、1,3-丁二烯生成反应、四氢呋喃生成反应,通过链段浓度表示了各个反应的反应速率及聚合物性质,并采用Aspen Polymer工艺流程模拟软件建立了PBT三...     

聚乙二醇-b-聚对苯二甲酸丁二醇酯嵌段共聚物在模拟土壤环境中的降解行为

根据降解过程中聚乙二醇-b-聚对苯二甲酸丁二醇酯(PEGT-b-PBT)嵌段共聚物失重率、特性黏度、表面形态等方面的变化初步评价了其在实验室模拟土壤环境中的降解行为.实验结果表明嵌段共聚物的降解与其组成密切相关,共聚物的特性黏度变化率和失重率随PBT组分含量的增大而降低,通过调节共聚物的组成可以达到调节降解速率的目的,水介质有助于降解产物的扩散.     

聚对苯二甲酸甲二酯的热分解行为及其动力学研究

研究了惰性气氛下聚对苯二甲酸甲二酯(PMT)的非等温热分解行为及其动力学,并与聚对苯二甲酸丁二酯 (PBT)进行了对比。研究发现,PMT的热降解过程包括两个主要失重阶段,其热分解反应不是一级反应。第一阶段的起始分解温度较低是由于产物的分子链末端基中含有Br或Cl能催化聚合物的降解反应;第二阶段为分子链主体的热分解过程,由于分子链中苯环的密度较大,分子链的热稳定性比具有较低苯环密度的PBT要高。而PBT的降解失重过程仅为一个阶段,为一级反应。     

对苯二甲酸丁二醇酯二聚体水/醇/氨解机理的理论研究

采用密度泛函理论M06-2X/6-311G（d）方法,对对苯二甲酸丁二醇酯二聚体的水/醇/氨解反应机理进行了量子化学理论研究。提出了各种可能的水/醇/氨解反应路径,对各反应的中间体、过渡态及产物进行了几何结构优化和频率计算以获得热力学与动力学参数值,分析了对苯二甲酸丁二醇酯二聚体主链酯键中的酰氧键位置水/醇/氨降解的反应机理。计算结果表明：水/醇/氨解条件下能够降低对苯二甲酸丁二醇酯二聚体主链酯键中的酰氧键裂解的反应活化能,使反应更易于进行,水/醇/氨解中主要基元反应步的反应能垒分别约为170.0、155.0和165.0 kJ/mol。对苯二甲酸丁二醇酯二聚体水解产物主要为对苯二甲酸和1,4-丁二醇,醇解产物主要为对苯二甲酸二甲酯和1,4-丁二醇,氨解产物主要为芳香腈和1,4-丁二醇等,其中1,4-丁二醇会进一步降解形成四氢呋喃。在对苯二甲酸丁二醇酯二聚体水/醇/氨解反应过程中,甲醇介质中的裂解反应优于氨气气氛中的反应、氨气气氛中的反应优于水分子环境中的反应,且反应温度的升高可以增加其自发性。     

聚对苯二甲酸乙二醇酯在超临界甲醇中解聚的研究

在间歇高压反应器中研究了聚对苯二甲酸乙二醇酯(PET)在超临界甲醇中的解聚反应特性, 通过扫描电镜观测了不同解聚条件下固相聚合物的内部结构,提出了解聚反应历程并得到了不同解聚条件下反应表观活化能。在甲醇的非临界区域,PET在甲醇中表现为溶胀过程,解聚程度低,反应在聚合物表面进行,反应表观活化能为27.19kJmol-1,解聚过程为传质、扩散控制;在甲醇的临界区域, PET完全溶于甲醇,解聚反应在均相中进行,反应表观活化能为89.79kJmol-1,为化学反应控制。     

我国PBT树脂市场发展趋势分析

<正>聚酯是由多元醇和多元羧酸聚合而成的一类聚合物的总称,一般可分为不饱和聚酯和饱和聚酯。目前已大规模生产的工程塑料级饱和聚酯主要包括聚对苯二甲酸二甲丁二醇酯(PBT)、聚对苯二甲酸丙二醇酯(PTT)、聚对苯二甲酸乙二醇酯(PET)、聚甲苯二甲酸环己烷二甲醇酯(PCT)及共聚聚酯等品种。PBT是由对苯二甲酸(PTA)或对苯二甲酸酯(DMT)与1,4-丁二醇(BDO)聚合而成的饱和聚酯     

聚合条件对聚对苯二甲酸丁二醇脂性能的影响

本文以二羟基丁基氯化锡为催化剂,采用环状对苯二甲酸丁二醇酯(CBT)开环原位聚合法制备了聚对苯二甲酸丁二醇酯(PBT),系统地研究了催化剂用量、聚合时间对pCBT聚合物的分子量、力学性能等的影响,并采用差示扫描量热(DSC)、动态粘弹法(DMA)对复合材料的结晶性能和玻璃化转变温度进行了表征。     

可堆肥脂肪-芳香族共聚酯PBAT是什么

正PBAT是聚对苯二甲酸己二酸丁二醇酯的缩写,或称己二酸对苯二甲酸-丁二醇共聚酯。PBAT是一种生物可降解无规共聚物。其具体合成路线如下:己二酸与1,4-丁二醇聚合成聚己二酸丁二醇酯(+水);对苯二甲酸二甲酯与1,4-丁二醇反应生成聚对苯二甲酸二甲酸丁二醇酯(+甲醇);将聚对苯二甲酸二甲酸丁二醇酯加到聚己二酸丁二醇酯中,使用钛酸四丁酯作酯交换催化剂,得到两种预制聚合物的共聚物PBAT。     

Degradation of poly(butylene terephthalate) in different supercritical alcohol solvents

Reactions were carried out in a batch autoclave reactor. Poly(butylene terephthalate) (PBT) and different alcohol solvents were used in the vessel. The reaction products were analyzed by infrared spectroscopy and gas chromatography/mass spectrometry. Alcoholysis of PBT occurred in supercritical methanol, ethanol, and propanol, and we obtained dimethyl terephthalate (DMT), diethyl terephthalate (DET), and dipropyl terephthalate (DPT), respectively. The conversion of PBT at different temperatures showed similar trends but different degradation degrees. The reactivity for the alcoholysis of PBT in supercritical methanol was much higher than those in supercritical ethanol and propanol. DMT and 1,4‐butanediol obtained from the depolymerization of PBT in supercritical methanol reached 98.5 and 72.3%, respectively, at 583 K for 75 min. The yield of DET reached 76% for 75 min. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

聚对苯二甲酸丁二醇酯在亚临界水中的催化解聚

研究间歇高压反应釜中聚对苯二甲酸丁二醇酯(PBT)以醋酸铜为催化剂在亚临界水中的解聚反应.主要考察反应时间(10-50min)和反应温度(493～553 K)对PBT解聚率以及产物产率的影响.反应产物分别采用气相色谱、气-质联用仪、傅里叶红外光谱、高效液相色谱和液-质联用仪进行分析,主产物为对苯二甲酸(TPA)和四氢呋喃(THF),产物中并未检测出1,4-丁二醇,与相关文献的研究结果不同.实验结果表明:PBT的解聚率随温度的升高、反应时间的延长而增加.在投料比8∶1(24.0g H2O/3.0 g PBT),催化剂醋酸铜0.03 g/3.0 g PBT,反应温度523K,时间50 min条件下,PBT可完全解聚,TPA和THF的产率分别为99.3％和83.1％.根据PBT在亚临界水中催化解聚产物的分析,提出PBT催化水解反应机理.通过实验数据关联,得出催化解聚反应级数为一级,反应活化能为141.6 kJ·mol-1.在微型毛细管反应器中结合显微镜研究了PBT在醋酸铜水溶液相态变化,温度上升至553 K停留19 min后PBT能完全溶解于水中,解聚反应在液相均相中进行.     

有色废弃PET材料化学回收新工艺

为了解决有色废弃PET材料回收难的问题,促进资源循环利用,研究了有色PET以超临界甲醇技术进行解聚,并脱色提纯得到对苯二甲酸二甲酯的工艺流程。探讨了有色PET在超临界甲醇中的降解规律,并对脱色方案进行了筛选。探索了不同级别的PET材料解聚条件的差异。结果表明：纤维级材料在265 ℃,11 MPa下,超临界甲醇解聚30 min后,用溶解-热过滤-沉析的方法脱色提纯,对苯二甲酸二甲酯的产率可达到85%,纯度达到99.9%以上,白度达到87.5%;瓶片级材料呈现的解聚规律与纤维级变化趋势相同,但达到相同的解聚率,明显需要更长的反应时间。     

Methanolysis of Poly（ethylene terephthalate）in Supercritical Phase

1 INTRODUCTIONPoly(ethylene terephthalate), commonly known as PET polyester, is extensively used for making synthetic fibers and package containers. The volume of PET consumed is rising by year, and thus the chemical recycling and reuse of waste PET are drawing much attention for the preservation of resources and the protection of environment. Through chemical recycling, waste PET is depolymerized into its valuable monomers such as dimethyl terephthalate (DMT), bis (hydroxyethyl) ter…     

Flame retardancy of poly(butylene terephthalate) blended with phosphorous compounds

The thermal degradation and flame retardancy of poly(butylene terephthalate) (PBT) were studied with a focus on the effect of phosphorous compounds. Thermogravimetric analysis, pyrolysis/gas chromatography/mass spectrometry (Py/GC/MS), and elemental analysis were used to analyze the flame retardancy, which were observed by an Underwriters Laboratory UL‐94 test and a cone calorimeter. The 50% degradation temperatures of PBT blends with phosphorous compounds were the same as that of neat PBT. Six scission products were assigned by Py/GC/MS. The burning times of the UL test of several PBT blends were much shorter than that of neat PBT. The relation between flame retardancy and thermal degradation was analyzed with respect to the results of the scission products and the char in burned polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2326–2333, 2004     

Recycling of waste PET‐bottles using dimethyl sulfoxide and hydrotalcite catalyst

The degradation of PET bottles has been successfully achieved using hydrotalcite as catalyst and dimethyl sulfoxide (DMSO) as solvent. The reaction was carried out at boiling point of DMSO (190°C) and degradation was complete in 10 min. The oligomer (tetramer) obtained was treated with NaOH at room temperature in methanol to get dimethyl terephthalate (DMT) and ethylene glycol (EG). Thus, it is a safe and cleaner process. Oligomer was characterized by MS, 13 C‐NMR, X‐ray diffractometric, and thermogravimetric analysis. DMT and EG were characterized by GC‐MS. DMT was also characterized by FT‐IR. GC‐MS analysis shows that the purity of DMT was 99%. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012     

Depolymerization of polyethyleneterephthalate in supercritical methanol

The depolymerization of polyethyleneterephthalate (PET) in supercritical methanol was carried out using a batch-type autoclave reactor. The total conversion and the yield of dimethylterephthalate (DMT) increased with rising temperature. The final yield of DMT at 300°C and 310°C reached 97.0% and 97.7%, respectively. The yield of DMT was markedly increased when the methanol density was 0.08 g/cm³, and leveled off at higher densities. A kinetic model to describe the depolymerization of PET in supercritical methanol was proposed, where the scission of one ester linkage in PET by a methanol molecule produces one carboxymethyl group and one hydroxyl group. The values of the forward reaction rate constant at different temperatures were determined by comparing the observed time dependence of carboxymethyl group concentration with that calculated by the proposed model. The activation energy was evaluated to be 49.9 kJ/mol, a value close to a literature value (55.7 kJ/mol). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2102–2108, 2001     

Depolymerization of poly(butylene terephthalate) using high‐temperature and high‐pressure methanol

Poly(butylene terephthalate) (PBT) was depolymerized in excess methanol at high‐temperature (473–523 K) and high‐pressure (4–14 MPa) conditions. Considering the critical point of methanol (512.6 K, 8.09 MPa), the reaction pressure was varied over the range of 6–14 MPa at the reaction temperature of 513 K. As a result, ca. 20 min was required to recover dimethyl terephthalate and 1,4‐butanediol, quantitatively, at any pressure, indicating that the supercritical state of methanol is not a key factor of degradation of PBT and that the effect of pressure is little. On the contrary, when the reaction temperature was varied over the range of 473–523 K at the pressure 12 MPa, the decomposition rate constant of PBT at the reaction temperatures (503–523 K) higher than the melting temperature of PBT (500 K) was much higher than that at 473–483 K. This result indicates that melting of PBT is an important factor for the short‐time depolymerization of PBT. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3228–3233, 2000     

番泻叶药渣超临界甲醇解产物的 GC／MS 分析

采用GC/MS分析解聚产物,研究了番泻叶药渣在超临界甲醇条件下的解聚产物。结果表明：番泻叶药渣超临界甲醇解聚产物所含成分复杂。 GC/MS分析鉴定出了58种化合物,化合物类型主要有酯类、酮类、醇类、烯烃类、酚类、含氮类及其它类化合物,其中大部分是甲酯类化合物,共27种,相对百分含量为59.43％;第二大类的是酮类化合物,相对含量为15.07％,首次鉴定出羽扇烯酮,相对含量达11.31％。甲醇参与了番泻叶药渣甲醇超临界解聚反应,同时存在酯化反应和超临界萃取作用,番泻叶药渣的超临界解聚反应的机理有待更深入的研究。该研究结果为番泻叶药渣的进一步利用提供了科学依据。     

Depolymerization of poly(trimethylene terephthalate) in supercritical methanol

The depolymerization of poly(trimethylene terephthalate) (PTT) in supercritical methanol was carried out with a batch‐type autoclave reactor at temperatures ranging from 280 to 340°C, at pressures ranging from 2.0 to 14.0 MPa, and for reaction time of up to 60 min. PTT quantitatively decomposed into dimethyl terephthalate (DMT) and 1,3‐propaniol (PDO) under the designed conditions. The yields of DMT and PDO greatly increased as the temperature rose. The yields of the monomers markedly increased as the pressure increased to 10.0 MPa, and they leveled off at higher pressures. The final yield of DMT at 320°C and 10.0 MPa reached 98.2%, which was much closer to the extent of the complete reaction. A kinetic model was used to describe the depolymerization reaction, and it fit the experimental data well. The dependence of the forward rate constant on the reaction temperature was correlated with an Arrhenius plot, which gave an activation energy of 56.8 kJ/mol. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2363–2368, 2004