Structure and properties of halogenated and nonhalogenated soy‐based polyols

Four polyols intended for application in polyurethanes were synthesized by oxirane ring opening in epoxidized soybean oil with hydrochloric acid, hydrobromic acid, methanol, and hydrogen. The structures of the polyols were characterized by spectroscopic, chemical, and physical methods. The brominated polyol had 4.1 hydroxy groups, whereas the other three polyols had slightly lower functionality. The densities, viscosities, viscous‐flow activation energies, and molecular weights of the polyols decreased in the following order: brominated > chlorinated > methoxylated > hydrogenated. All the polyols were crystalline solids below their melting temperature, displaying multiple melting peaks. The methoxylated polyol was liquid at room temperature, whereas the other three were waxes. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3900–3910, 2000     

氟橡胶/改性乙丙橡胶并用胶的热稳定性

采用热分析技术考察了氟橡胶及氟橡胶(FPM)/改性乙丙橡胶(MEPDM)并用胶在氮气中的热稳定性, 通过微分法与积分法两种动力学方法计算出了FPM及FPM/MEPDM并用胶的热分解活化能E和指前因子A. 结果表明, 并用胶的热分解温度稍高于纯的氟橡胶, 但热分解活化能略低于氟橡胶, FPM、FPM/MEPDM(5%)和FPM/MEPDM(10%)的热分解活化能分别为251.74、244.98和219.60 kJ·mol-1; 热分解反应级数n均为0.95. 随着失重百分率的增大, 热分解活化能增大.     

柠檬酸镧催化双基推进剂的非等温热分解反应动力学

采用TG-DTG和DSC技术研究了含二缩三乙二醇二硝酸酯(TEGDN)和硝化甘油(NG)的混合酯、硝化棉(NC)和用作燃烧催化剂的柠檬酸镧组成的双基推进剂在常压和流动态氮气气氛下的非等温热分解反应动力学. 结果表明, 该双基推进剂的热分解过程存在2个失重阶段: 第I失重阶段为混合酯的挥发分解过程; 第II失重阶段为主放热分解反应, 机理服从三级化学反应, 减速型α-t曲线, 动力学参数: Ea=231.14 kJ·mol-1, A=10^23.29 s-1, 动力学方程为dα/dt=10^22.99(1-α)³ e^-2.78×104/T. 由外推起始点温度(Te)和峰顶温度(Tp)计算得出该双基推进剂的热爆炸临界温度值分别为Tbe=463.62 K, Tbp=477.88 K. 反应的活化熵(⊿S^≠)、活化焓(⊿H^≠)和活化能(⊿G^≠)分别为219.75 J·mol-1·K-1, 239.23 kJ·mol-1和135.96 kJ·mol-1.     

Single Crystal,Molecular Accumulation and Thermal Analysis of Tetrazolo[l,5‐b][1,2,4]triazine

The nitrogen content of tetrazolo[l,5‐b][1,2,4]triazine is 68.9%. It has a good application prospect in energetic material field. The synthesis was carried out, and the single crystal was cultivated. The analysis showed that the two rings of tetrazolo[l,5‐b][1,2,4]triazine are in the same flat, and the molecular accumulation displayed the net‐like structure in the space. The thermal decomposition process was studied. The relationship between weight loss and temperature, and the thermal decomposition temperature were gained from thermogravimetry‐differential thermogravimetry and differential scanning calorimetry. These provide the reference for its application in energetic material.     

Thermal behaviour of metal soaps from biodegradable rubber seed oil

Soaps are a class of surface active compounds derived from natural oils and fats. Double decomposition reactions permit the synthesis of metallic soaps, which are long-chain carboxylates of metal ions, from alkaline ones such as sodium, potassium or ammonium soaps. Metallic soaps are commercially important as they find use in diverse applications such as driers in paints or inks, components of lubricating greases, heat stabilizers for plastics (especially PVC), catalysts and water proofing agents, fuel additives and cosmetic products amongst others. Many of these applications are related to the thermal properties of these compounds and the thermal behaviour of metal soaps in terms of decomposition processes is of great importance. Rubber seed oil (RSO) which is an unsaturated triglyceride abundantly available in Nigeria, India and Australia is an excellent starting material for metal soaps. In this study rubber seed oil having 2.2% myristic acid, 7.6% palmitic acid, 10.7% stearic acid, 20.61% oleic acid, 36.62% linoleic acid, 22.5% linolenic acid was used in making barium, calcium, cadmium and zinc soaps. The thermal behaviour of soaps (Ba, Ca, Cd and Zn) of rubber seed oil for use as additives in the processing of poly(vinyl chloride) (PVC) was investigated by thermal gravimetry and differential scanning calorimetry. The stability of the soaps was examined by thermogravimetry up to 873 K at a constant heating rate of 10 °C min⁻¹. The soaps were found to be thermally stable up to 473 K as they recorded less than 5% mass loss at this temperature with values of apparent activation energy for decomposition varying from 52 to 96 kJ mol⁻¹. Differential scanning calorimetric studies of the soaps revealed melting and decomposition behaviour of metal soaps.     

Structure and properties of polyurethanes based on halogenated and nonhalogenated soy–polyols

Four polyols were prepared by a ring opening of epoxidized soybean oil with HCl, HBr, methanol, and by hydrogenation. Two series of polyurethanes were prepared by reacting the polyols with two commercial isocyanates: PAPI and Isonate 2143L. Generally, the properties of the two series were similar. The crosslinking density of the polyurethane networks was analyzed by swelling in toluene. Brominated polyols and their corresponding polyurethanes had the highest densities, followed by the chlorinated, methoxylated, and hydrogenated samples. The polyurethanes with brominated and chlorinated polyols had comparable glass transition and strength, somewhat higher than the polyurethane from methoxy containing polyol, while the polyurethane from the hydrogenated polyol had lower glass‐transition and mechanical properties. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4062–4069, 2000     

Thermal decomposition mechanism and quantum chemical investigation of hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO)

The thermal decomposition mechanism of hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO) compound was studied by means of differential scanning calorimetry (DSC), thermogravimetry and derivative thermogravimetry (TG-DTG), and the coupled simultaneous techniques of in situ thermolysis cell with rapid scan Fourier transform infrared spectroscopy (in situ thermolysis/RSFTIR). The thermal decomposition mechanism is proposed. The quantum chemical calculation on HNTO was carried out at B3LYP level with 6-31G+(d) basis set. The results show that HNTO has two exothermic decomposition reaction stages: nitryl group break first away from HNTO molecule, then hydrazine group break almost simultaneously away with carbonyl group, accompanying azole ring breaking in the first stage, and the reciprocity of fragments generated from the decomposition reaction is appeared in the second one. The C–N bond strength sequence in the pentabasic ring (shown in Scheme 1) can be obtained from the quantum chemical calculation as: C3–N4 > N2–C3 > N4–C5 > N1–C5. The weakest bond in NTO⁻ is N7–C3. N11–N4 bond strength is almost equal to N4–C5. The theoretic calculation is in agreement with that of the thermal decomposition experiment.      

Preparation and characterization of polyurethane electrical insulating coatings derived from novel soybean oil‐based polyol

As a viable alternative to the petrochemical polyols in polyurethanes (PUs), a new soybean oil‐based polyol (PSBO) with high functionality of hydroxyl groups and built‐in (preformed) urethane bonds was introduced. At first, a facile and improved method was developed for the transformation of epoxidized soybean oil (ESBO) to carbonated soybean oil (CSBO). Then ring‐opening reaction of carbonated oil with ethanolamine (ETA) led to the polyol. After characterization by conventional spectroscopic and analytical methods, PSBO was used for the formulation of novel one‐pack PU electroinsulating wire enamels. Tunable mechanical, thermal, and electrical properties for the final PUs were achieved by replacing 10 wt% of PSBO with poly(propylene glycol) (PPG) at different number average molecular weights of 725, 1000, 2000, 4000. Investigation of the results showed that these soy‐based PUs offer excellent thermal and electrical insulating properties. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of organophosphate antioxidant on the thermo-oxidative degradation of a mineral oil

This study shows the synthesis, characterization, and evaluation of the effect of organophosphate antioxidant on the thermo-oxidative degradation of a mineral oil. The organophosphate was synthesized by nucleophilic substitution (S_N2) of hydrogenated cardanol. For this study, were employed thermogravimetry, derivative thermogravimetry, differential scanning calorimetry, and differential thermal analysis techniques. The results showed that organophosphate contributed for thermo-oxidative stability of mineral oil (initial decomposition temperature (IDT) mineral oil: 91.28 °C < IDT mineral oil + organophosphate (1%): 156.42 °C). The organophosphate obtained shows significant thermal stability when compared with other compound of the same class (diphenyl phosphate).     

Thermal properties of chlorosulfonated polyethylene via gas–solid phase method

The thermal properties of chlorosulfonated polyethylene (CSM), which was prepared via gas–solid phase method, were studied in this article. The thermal curves were completely tested by differential thermal analysis, thermogravimetry, and differential thermogravimetry. The results showed that CSM 3550 and CSM 3570 prepared by gas–solid phase method had more excellent thermal properties (high initial/final temperature of degradation) than those via solution method, due to the uniform chlorine distribution of them in macromolecular chain. The differential scanning calorimetry curves showed that the transitions of CSM 3550 and CSM 3570 from glassy to the elastic state were also higher than those via solution method. Particularly, CSM 3570 was amorphous and no clear melting peak was observed during the melting process.     

Contribution of Thermal Analysis For Characterization of Asphaltenes From Brazilian Crude Oil

The thermal decomposition of asphaltenes is mainly responsible for the formation of coke in petroleum processing. Phenomena involved are not clearly understood, because of the difficulties to characterize such heavy components. This paper reports the application of thermal analysis techniques to study the thermal behavior of asphaltenes from Brazilian oil. The approach involves kinetic studies of the thermal decomposition of asphaltenes under controlled conditions by thermogravimetry (TG), characterization of volatile fractions by thermogravimetry and differential thermal analysis coupled with gas chromatography/mass spectrometry (TG-DTA/GC/MS) and by gas chromatography/mass spectrometry (GC/MS) in the volatile recovered. The coke formed was also studied after being decomposed into smaller molecules using selective oxidation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal kinetic studies on the decompositions of cefuroxime lysine in different atmospheres and heating rates

The thermal decomposition of a new antibiotic agent, cefuroxime lysine, was investigated by thermogravimetry analysis/derivative thermogravimetry and differential scanning calorimetry (DSC) methods in anoxic and oxidative environments. The influence of heating rates (including 5, 10, 15, and 20 °C/min) on the thermal behavior of cefuroxime lysine was revealed. By the methods of Kissinger and Flynn–Wall–Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.     

Structural Properties and Thermal Behavior of Li2CO3–BaCO3 System by DTA,TG and XRD Measurements

The binary system Li₂CO₃–BaCO₃ was studied by means of differential thermal analysis (DTA), thermogravimetry (TG) and X-ray phase analysis. The composition of carbonate and CO₂ partial pressure influence on the thermal behavior of carbonate were examined. It was shown that lithium carbonate does not form the substitutional solid solution with barium carbonate, however the possible formation of diluted interstitial solid solutions is discussed. Above the melting temperature the mass loss is observed on TG curves. This loss is the result of both decomposition of lithium carbonate and evaporation of lithium in Li₂CO₃–BaCO₃ system. Increase of CO₂ concentration in surrounding gas atmosphere leads to slower decomposition of lithium carbonate and to increase the melting point. This revised version was published online in July 2006 with corrections to the Cover Date.     

高分子固体电解质LiNO_3-LiOOCCH_3/聚丙烯酸锂的合成与性能研究

以丙烯酸和氢氧化锂为原料用反相乳液聚合法合成聚丙烯酸锂 (PAALi) ,将其熔于低共熔盐 (一定比例的LiNO3 LiOOCCH3混合物 )中得到新型高分子固体电解质 (SPE) ,用XRD、IR、DTA、TG DTG等技术进行了表征 ,讨论了影响合成PAALi工艺及新型固体电解质电阻率的主要因素 ,在LiNO3 LiOOCCH3摩尔比为 1∶1时 ,将其按质量百分比 80∶2 0与聚丙烯酸锂混合均匀并熔融 ,得到的电解质其室温离子电导率可达 2× 10 - 5S·cm- 1 ,大量低共熔盐的加入可明显提高SPE的离子导电率 .XRD、DTA及TG DTG结果表明低共熔盐与聚丙烯酸锂形成了新的配合物     

Thermal analysis of N-phenylbenzohydroxamic acid (PBHA)

The thermal dissociation of N-phenylbenzohydroxamic acid was studied by differential thermal analysis (DTA) and thermogravimetry (TG). The DTA curve showed two exothermic peaks caused by melting and/or decomposition of the compound.     

Thermal behavior of ara?a oil (Psidium cattleianum Sabine)

The ara?á is a well-known fruit, which belongs to the Myrtaceae family, Psidium cattleianum Sabine species, frequently found in the southern region of Brazil. The extraction of ara?a oil was carried out from seeds, and the fatty acid profile of this oil indicates the predominant presence of linoleic acid (81.38%). Thermogravimetry, derivative thermogravimetry, and differential scanning calorimetry (DSC) were used to characterize this oil. In addition, this oil was evaluated by DSC from 25 to ?60?°C, where the crystallization behavior was verified. Details concerning thermal decomposition as well as data of kinetic parameters of these stages have been described here. The kinetic behavior of the thermal decomposition was evaluated from several heating rates with mass samples of 5 and 20?mg in open crucibles under nitrogen and synthetic air atmospheres.     

Carbon nanofibers reinforced soy polyol-based polyurethane nanocomposites

Vapor-grown carbon nanofiber (CNF)-modified soy polyol-based polyurethane (PU) nanocomposites with different hydroxyl value of polyols (OH) were synthesized. The glass transition, thermal stability, mechanical properties, and morphology of the PU nanocomposites were characterized through differential scanning calorimetry, thermogravimetry, universal test machine, and scanning electron microscopy. The addition of CNFs increased the glass transition temperature as well as significantly improved tensile strength and Young’s modulus of PU nanocomposites. Meanwhile, thermal and mechanical properties of PU composites were influenced by the different hydroxyl value of polyols due to those different structures. In particular, in the case of 2 mass% CNF addition in PU derived from soy polyol with the OH number of 164 mg KOH g^?1, 20.8 °C improvement in the glass transition temperature, 115 % increment in tensile strength, and nearly eightfold increase in Young’s modulus were obtained.     

Geological and thermal characterization of Eskişehir region oil shales

In this study, geological consideration and thermal characterization of oil shale samples were studied. Geological considerations of oil shale samples were studied using Rock–Eval analysis and it was observed that the kerogen type of all oil shale samples were in the majority of Type-I and II. Thermal characteristics and kinetics analysis of oil shale samples were studied by non isothermal differential scanning calorimeter (DSC) and thermogravimetry (TG/DTG). In air atmosphere, two different mechanisms causing loss of mass were observed known as loss of moisture, and decomposition of kerogen and bitumen. Kinetic parameters of the samples are determined using ASTM-I and II (DSC), Kissinger, and KAS (TG–DTG) kinetic models and the results are discussed.     

Effects of fullerenes on thermal behaviors of polyethylene glycol

Effects of fullerenes including FS, EFS and pure C₆₀ on thermal behaviors of polyethylene glycol (PEG) have been studied by employing thermogravimetry-differential thermogravimetry (TG-DTG), differential scanning calorimeter (DSC) and off-line furnace-type pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The products were collected by Cambridge filter pad which was widely used in analyzing the combustion products of cigarette. The results showed that the addition of fullerenes obviously restrained the thermal decomposition of PEG. The initial decomposition temperatures (IDT) and maximum decomposition peak temperatures (MDT) were evidently postponed by the addition of fullerenes. Pyrolysis products with one or two hydroxyl end groups obviously increased with the addition of 10% C60. The reasons of the changes were discussed from the aspects of reaction mechanisms.