Sb/Ti复配催化半光聚酯可纺性研究

通过对五种不同Sb/Ti配比半光聚酯热性能研究发现,Sb/Ti复配聚酯熔融结晶温度Tmc高于锑和全钛,50/50温度最高,复配聚酯熔体成型性能弱于锑系;复配聚酯冷结晶峰温Tc高于锑系,后加工性能强于锑系。采用UDYDT路线的可纺性研究发现,复配聚酯原丝粘度降高于锑系聚酯,原丝强度高于锑系,DT丝的变化未表现出明显规律,纺丝温度296℃时,复配聚酯DT的强度可以达到与锑相当。     

聚丁二酸丁二醇-共-对苯二甲酸丁二醇酯的热降解动力学

在高纯氮气保护下,采用不同的升温速率,用热失重法对聚丁二酸丁二醇-共-对苯二甲酸丁二醇酯(PBST)共聚酯的热降解行为和热降解动力学进行了研究。用Kissinger、Flynn-Wall-Ozawa及Friedman 3种方法对比计算了PBST共聚酯在氮气气氛中的热降解活化能,并对PBST共聚酯的热老化寿命进行了探讨。结果表明在氮气气氛中共聚酯的热稳定性随BT含量增加而增强,不同组分的PBST共聚酯热降解均为1级反应,分解活化能E均随BT摩尔分数的增加而增大。     

耐热改性剂的热降解动力学研究

以热失重法研究甲基丙烯酸缩水甘油酯(GMA)共聚物耐热改性剂的热降解动力学。采用Kissinger、FWO和Friedman三种不同的方法对其热稳定性进行了探究。结果表明:Kissinger法得到的CHGS降解活化能(E_a)为224.511 kJ/mol,表观指前因子(A)为2.558×10~(13);FWO法及Friedman法计算结果基本一致,E_a为221.461 3 kJ/mol,反应级数n为1.110 7。     

不同催化体系所得聚酯的等温结晶研究

用DSC法对三氧化二锑 (Sb2 O3)、氟钛酸钾 (K2 TiF6 )、钛酸四丁酯 (Ti(OC4 H9) 4)及乙二醇锑(S -2 4) 4种催化体系所得聚酯进行等温结晶研究 ,求得了结晶速率常数 (k)和Avrami指数 (n)。结果表明 ,锑系催化剂所得聚酯的结晶速度总体大于钛系催化剂所得聚酯 ,其中以Sb2 O3催化所得聚酯结晶速度最快 ,而Ti(OC4 H9) 4催化所得聚酯结晶速度最慢。DTA结果表明锑系催化剂所得聚酯冷结晶温度低于钛系催化剂所得聚酯 ,与结晶速度测试结果相一致。     

CHDM改性共聚酯的热降解动力学研究

采用热重分析法研究了在氮气氛围中不同用量1,4-环己烷二甲醇(CHDM)改性共聚酯(PETG)在不同升温速率下的热稳定性,利用Flynn-Wall-Ozawa方法、Friedman方法研究了PETG共聚酯的热降解动力学.结果表明:在相同的升温速率下,随着CHDM用量的提高,PETG共聚酯在较低的温度下开始降解,且降解加...     

用铝硅复合催化剂催化聚合的聚酯性能研究

以三氧化二锑(Sb2O3)、不同质量比的铝酸钠/硅酸钠复合物分别作为聚酯缩聚催化剂制取聚酯切片,利用凝胶渗透色谱(GPC)、色值、差示扫描量热(DSC)及热失重(TG)对聚合产物分别进行分析.结果表明:以铝硅复合催化剂F1[n(铝酸钠)∶m(硅酸纳)=4∶1]催化制取的聚酯相对分子质量及分子质量分布接近以Sb2O3催化制取的聚酯,而且色相指标比用Sb2O3催化制取的聚酯好,其白度L值高,黄度b值低;复合催化剂制取的聚酯的玻璃化转变温度(Tg)低于Sb2O3催化制取的聚酯,但结晶温度高于Sb2O3催化的聚酯,表明聚酯的结晶能力有所提高;复合催化剂催化聚合的聚酯热性能与常规Sb2O3催化的聚酯基本接近.     

膜级钛系聚酯与锑系聚酯的成膜性能比较

利用流延膜挤出机、拉膜机分别对锑(Sb)系聚酯和钛(Ti)系聚酯进行挤出、拉伸成膜,考察了两种聚酯的成膜性能,对两种聚酯在加工过程中的热稳定性以及薄膜的热性能、力学性能、光学性能、取向结构进行了表征。结果表明:在挤出、拉伸过程中,Ti系聚酯的黏度降高于Sb系聚酯,Ti系聚酯切片的结晶度明显小于Sb系聚酯,但Ti系聚酯薄膜的结晶度与Sb系聚酯薄膜相当;在相同的成膜工艺下,Ti系聚酯薄膜的弹性模量、光学性能与Sb系聚酯薄膜相当,拉伸强度高于Sb系聚酯薄膜,断裂伸长率低于Sb系聚酯薄膜,双折射率大于Sb系聚酯薄膜。     

PTMG-b-PET共聚酯的合成及性能

以对苯二甲酸、乙二醇以及聚四氢呋喃(PTMG)为原料,采用熔融缩聚法合成了不同PTMG比例的聚对苯二甲酸乙二醇酯-聚四氢呋喃(PET-PTMG)聚醚酯,研究了PTMG含量对共聚酯缩聚反应过程的影响。利用红外光谱法、核磁共振波谱法分析了共聚酯结构、序列分布,利用差示扫描量热分析(DSC)、热失重分析研究了共聚酯热性能、结晶动力学以及热稳定性。研究表明,投入体系的聚醚基本都进入了聚合物分子链;PTMG含量增加,聚合反应动力黏度增长变缓,共聚酯玻璃化转变温度(T_g)、结晶温度(T_c)、熔点(T_m)均明显降低,熔融结晶温度(T_mc)先上升后下降,试验制备的共聚酯较常规PET结晶速率更快。在氮气氛围中,共聚酯的热降解为一阶反应,PTMG含量增加,共聚酯热稳定性明显降低。     

络合钛复合纳米凹凸棒土催化聚酯反应研究

以钛酸四丁酯、柠檬酸为基本原料制备了一种新型络合钛聚酯催化剂,并将其与纳米凹凸棒土(ATP)复合,得到一类复合催化剂,对络合钛及复合催化剂分别进行了红外和透射电镜表征,证实了金属钛与柠檬酸配体发生了络合,复合催化剂具有良好的分散状态。通过催化聚酯反应对络合钛及多种复合催化剂的性能进行了评价,结果表明:与常规聚酯催化剂Sb2O3相比较,络合钛催化活性约为Sb2O3的6倍,但产品色相b值较高(大于15.60);将络合钛与纳米凹凸棒土以2:1的质量比负载后,催化反应得到的聚酯b值从16.30降为3.79,综合反应速度和聚酯色相的结果,认为络合钛与凹凸棒土的合适质量配比为5:2。此外,讨论了复合催化剂对聚酯物化性能的影响,通过DSC、TGA等测试手段,发现络合钛复合纳米凹凸棒土作催化剂制备的聚酯的结晶温度比Sb2O3催化制备的聚酯要高7℃以上,熔点高6℃左右,二甘醇含量更低,其热降解性能相近。     

基于热失重法的热塑性聚氨酯热氧老化特性分析及其降解动力学模型

采用热塑性聚氨酯（TPU）在40℃、50℃、60℃、70℃下进行人工加速热老化,利用热失重分析法（TG）对TPU热降解过程进行分析,探讨了TPU在老化过程中的热失重特性及其热降解动力学模型。测试结果表明,TPu热失重过程可分为硬段和软段热裂解两个阶段;硬段和软段各自最快热降解速率随老化温度和时间的增加没有明显变化。然而,通过对TPU热失重5％时对应的温度进行分析,得出该温度随着热氧老化时间的延长而逐渐下降,说明TPu的热稳定性随老化时间的延长而逐渐降低。采用Coats—Redfern方法对TPU的热降解动力学进行研究,结果表明,TPU的热降解符合0级反应动力学方程。     

含磷共聚酯纤维的阻燃及热降解性能研究

采用含磷反应型阻燃剂、对苯二甲酸和乙二醇共聚,纺丝得到共聚酯纤维,研究了共聚酯纤维的阻燃性能和热降解行为。结果表明,共聚酯纤维含磷质量分数为0．36％,极限氧指数达31．5％,燃烧时无熔滴、烟雾产生。共聚酯起始热分解温度达391℃,热降解温度390～470℃,氮气气氛下的热分解表观活化能为170～200 kJ／mol(分解度为0．15～0．80),且随分解度的增加而增加,其热降解机理比较复杂。     

Poly(styrene‐co‐butyl acrylate) latex‐reinforced polyester nonwoven fabric composites: Thermal and morphological studies

A series of thermoplastic composites were fabricated by impregnating the polyester nonwoven fabric in poly(styrene‐co‐butyl acrylate) latex having different monomer compositions of styrene and butyl acrylate viz., 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 weight by weight. Thermogravimetric analysis (TGA) of the composites was performed to establish the thermal stability and their mode of thermal degradation. From TGA thermograms, a slight improvement in thermal stability of the composites was noticed compared to polyester nonwoven fabric. Degradation kinetic parameters were obtained for the composites using Broido and Coats–Redfern methods. The activation energy (E_a) of the composites for the thermal degradation process lies in the range 7.1–261 and 60–264 kJ/mol for Broido and Coats–Redfern methods respectively. Morphology of the tensile‐fractured composites was studied using scanning electron microscopic technique. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

水性聚酯树脂的制备及耐水解稳定性

本文对水性聚酯树脂合成原料的选择进行了分析,采用熔融法分别合成了聚酯主链由二羟甲基丙烷酸提供分别为100％、75％、50％、25％、O％功能性羧基,而另外0％、25％、50％、75％、100％的羧基由“偏苯三甲酸酐”提供的5个品种水性聚酯树脂。并对所合成的聚酯树脂进行了耐水解性比较,其结果表明,随着二羟甲基丙烷酸提供的羧基的比例增加,其聚酯树脂耐水解程度也随之增加。     

Curing,gelling, thermomechanical,and thermal decomposition behaviors of anhydride‐cured epoxy (DGEBA)/epoxidized soybean oil compositions

This work was aimed at studying the effects of incorporation of epoxidized soybean oil (ESO) in a standard bisphenol A‐type epoxy resin (EP) cured by anhydride hardener. The EP/ESO ratio was set for 100/0, 75/25, 50/50, 25/75, and 0/100 (wt%/wt%). The investigations performed covered the curing, rheology (gelling), thermomechanical (TMA), and thermogravimetric analysis (TGA) of the EP/ESO compositions. The results showed that the dilution of EP with ESO was accompanied with marked changes in the curing, gelling behavior, and final properties. Differential scanning calorimetry revealed that the crosslinking of EP/ESO ≥ 50/50 occurred in two steps. This has been considered for the cure schedule set. The gel time of EP/ESO, determined at T = 100, 120, 140°C, respectively, increased with increasing ESO content. The activation energy of gelling increased with increasing ESO content. The glass transition temperature decreased with increasing ESO content. The samples were transparent that was traced to the presence of domains smaller in size than the wavelength of the visible light based on atomic force microscopy inspection. According to TMA, the coefficient of thermal expansion in the glassy state increased with increasing ESO content but was independent of the latter in the rubbery stage. TGA indicated that with increasing ESO content the thermal degradation started earlier and the char yield decreased. The Ozawa, Flynn, and Wall (OFW) approach was adapted to TGA tests to calculate the activation energy of thermal degradation. The activation energy depended on the ESO content of the EP/ESO blends and also on their actual decomposition stage. The latter means a limitation for the OFW approach. POLYM. ENG. SCI., 54:747–755, 2014. © 2013 Society of Plastics Engineers     

废旧聚酯纺织品的热降解动力学

通过分析废聚酯纺织品的组分、黏度、含水率,并与常规聚酯切片对比,证明其由纯聚酯纤维布料组成,黏度低而杂质含量高。在氮气气氛下采用热失重分析测试布泡料和常规聚酯切片的热降解参数,发现布泡料的起始分解温度和最大分解速率温度都低于常规聚酯切片。用Kissinger法分析常规聚酯切片和白布泡料的热降解动力学,样品的ln(β/T2max)和1000/Tmax之间均呈现良好的线性关系,说明Kissinger方程可以很好地表述其热降解过程。计算发现白布泡料的活化能和指前因子均低于常规聚酯切片。     

PEFT共聚酯的热氧化分解行为研究

采用热重(TG)分析法研究2,5-呋喃二甲酸(FDCA)质量分数分别为0,25％,50％,75％,100％的聚对苯二甲酸-2,5-呋喃二甲酸乙二醇共聚酯(PEFT)的热氧化分解行为,使用Kinssinger法、Ozawa法和Coats-Redfen法对PEFT热氧化分解的表观活化能(Ea)和反应机理进行了分析.结果表明...     

Structural,mechanical, thermal,and electrical properties of carbon black reinforced polyester resin composites

Carbon black (CB) reinforced polyester resin (PR) composites (CPC) have been fabricated from mechanical mixtures of liquid PR and CB powder having 0–50 wt% CB contents and cured with 1% of methyl ethyl ketone peroxide at room temperature under a pressure of 50 MPa. The samples have been examined by the Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD) technique, scanning electron microscopy (SEM), mechanical test, micromechanical test, differential thermal analysis (DTA), and thermogravimetric analysis (TGA) and electrical test. FTIR spectra confirm the physical and chemical bond formations between CB and PR. XRD shows a very partial crystalline structure in cured PR and hexagonal structure in CB particles. SEM exhibits a clear dispersion of CB particles in PR matrix at lower loading and aggregates at higher loading. With the increase of fillers, while the tensile and flexural strengths of CPCs decrease, the Young's and tangent modulii increase by 80 and 100%, respectively. These increments are found consistent with the theoretical values. The degree of physical crosslinking between CB and PR as well as the aspect ratio of CB in CPCs are found to increase with the increase of filler. A remarkable increase in microhardness of about 61% at 50 wt% CB content is observed. The TGA represents that the thermal degradation temperature for pure PR is 373°C and that for CPC is 393°C. The dielectric constant of CPCs decreases with increasing frequency, whereas the ac‐ and dc‐ conductivities of CPC are found to increase with CB content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40421.     

Synthesis and Thermal Study of Cured Epoxy-Acrylate-Maleate,Unsaturated Polyester and Their Interpenetrating Networks of Varying Compositions

Epoxy-acrylate-maleate of bisphenol-C (ECAM), unsaturated polyester resin of phthalic anhydride, maleic anhydride and propylene glycol (PMP) were synthesized. ECAM, PMP and their varying compositions (25–75 wt%) were cured using MEKP and cobalt naphthenate and characterized by IR, DSC and TGA techniques. Interpenetrating networks possess intermediate thermal stability of ECAM (300°C) and PMP (227°C) and followed single step degradation with fractional order kinetics (0.6–2.4) leaving 10–25% residue above 400°C. Low magnitudes of energy of activation and frequency factor of interpenetrating networks indicated improvement in flexibility due to toughening of PMP by ECAM of varying compositions.     

Effects of the o‐aromatic ring in the molecular chain on the properties of polyester polyols

A series of liquid polyester polyols from adipic acid (AA), phthalic anhydride (PA), ethylene glycol, propanediol‐1,2, and trihydroxymethylpropane, varying in the molar ratio of PA to AA, were prepared. The effects of the o‐aromatic ring in the molecular chain, which came from PA, on the viscosity, glass‐transition temperature, and thermal degradation temperature of the polyester polyols were studied with viscometry, differential scanning calorimetry, and thermogravimetry. The intrinsic viscosity and glass‐transition temperature increased with the concentration of the o‐aromatic ring increasing. The temperature of the maximum thermal degradation rate for aliphatic polyester polyols was 434.20°C. Two steps of thermal degradation were found when there were o‐aromatic rings in the molecular chain. One thermal degradation temperature was 358.36–360.48°C, and the other was 412.85–427.18°C. Polyester polyols with o‐aromatic rings had higher stability at lower temperatures (<240.00°C). However, aliphatic polyester polyols had higher stability at higher temperatures (300.00–480.00°C). The activation energy and order of degradation were calculated from thermogravimetric curves. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1617–1624, 2002