绿色固化剂DDI与HTPB的固化反应实验研究

为研究新型绿色固化剂二聚酸二异氰酸酯(DDI)与端羟基聚丁二烯(HTPB)的固化过程,通过不同组分配比实验分别研究了DDI、TDI、IPDI和HTPB的固化反应效果,计算了其流变反应速率常数。结果表明,60℃时DDI、TDI、IPDI与HTPB的流变反应速率常数分别为:kDDI=0.005 1,kTDI=0.005 6,kIPDI=0.004 4;不同类型固化剂与HTPB固化反应的适用期均可以满足实际使用要求,DDI的固化反应速率大于IPDI而小于TDI。从适用期、反应速率及其低毒可再生性考虑,DDI可以作为HTPB黏结剂体系的固化剂。     

FT-IR法研究粒铸EMCDB推进剂的固化反应动力学

用傅里叶变换红外光谱(FT-IR)法对聚乙二醇(PEG)/异佛尔酮二异氰酸酯(IPDI)体系和IPDI封端的PEG预聚物/硝化棉(NC)体系固化反应动力学进行了研究,同时考察了复合燃烧催化剂(铅盐、铜盐和炭黑组成质量分数0.3%)对二体系的固化反应动力学的影响。实验结果表明:二体系均随温度升高,反应速率加快;相同温度下,催化剂的加入明显加快了固化反应速率,并降低了其表观活化能,但不改变固化反应级数(仍为二级反应)。     

混合异氰酸酯固化剂对HTPB固化反应的影响研究

为了缩短以端羟基聚丁二烯(HTPB)为粘结剂组分的浇注高聚物粘结炸药(PBX)及固体推进剂的固化时间,研究了二苯基甲烷二异氰酸酯(MDI)、异佛尔酮二异氰酸酯(IPDI)及其不同比例混合物作为固化剂对反应的影响。结果表明,用IPDI/MDI摩尔比为3∶1的混合固化剂的适用期超过6 h,固化时间为4 d,较单独使用IPDI作为固化剂的固化时间短,可以满足生产要求,是较理想的固化剂。     

二羟甲基二茂铁在HTPB黏合剂体系中的作用研究

以1,1′–二羧基二茂铁(FDC)为原料合成了1,1′–二羟甲基二茂铁(FDM),并利用核磁(NMR)、红外(IR)表征了产物的结构。随后将FDM加入到端羟基聚丁二烯(HTPB)中,分别采用甲苯二异氰酸酯(TDI)或者异佛尔酮二异氰酸酯(IPDI)两官能度异氰酸酯固化,得到含有二茂铁衍生物的聚氨酯。采用旋转黏度计检测了固化过程中的黏度变化;使用X射线光电子能谱仪(XPS)、热重分析(TG)对HTPB型聚氨酯的性能进行了表征。结果显示,FDM交联到HTPB型聚氨酯网络中,有效地解决了二茂铁衍生物在聚氨酯中的迁移问题。此外,FDM具有较高反应活性和固化催化作用,含质量分数10%FDM的HTPB–IPDI固化体系的黏度增长远低于不含FDM的HTPB–TDI体系的黏度增长。在需要添加固化催化剂的活性较低固化剂中,或者活性较低的固体推进剂黏合剂中,FDM以其双重的燃烧催化活性和固化催化活性有望得到应用。     

丁羟推进剂黏结体系中增塑剂迁移的分子模拟

为克服固体推进剂中增塑剂与黏结体系之间加速老化实验手段的不足,构建了增塑剂和黏结体系的分子模型.利用分子模拟方法在COMPASS力场下分析了增塑剂癸二酸二辛酯(DOS)在由端羟基聚丁二烯(HTPB)和异佛尔酮二异氰酸酯(IPDI)组成的黏接体系中的相容性和扩散性.用无定形动力学方法计算组分的溶度参数,判断DOS与HTPB、IPDI的相容性.结果表明,DOS与HTPB、IPDI相容性较好.这与由共混方法计算的结合能得到相容性好的结论一致;通过分子动力学方法模拟计算得到增塑剂DOS在黏结体系(HTPB-IPDI)中的扩散系数为1.2×10-7cm2/s.     

催化剂对HTPB-IPDI黏合剂体系的固化催化作用研究

为了降低黏合剂端羟基聚丁二烯( HTPB)和固化剂异佛尔酮二异氰酸酯(IPDI)的固化反应温度,提高生产效率,缩短固化时间,研究了二月桂酸二丁基锡(T-12)、乙酰丙酮铁(Fe(AA)3)和三苯基铋(TPB)3类催化剂对HTPB -IPDI黏合剂体系固化催化作用的影响.实验结果表明,加入TPB质量分数为0.05％时,其适用期可以达到6h,TPB是HTPB -IPDI黏合剂体系比较理想的固化催化剂.     

不同二异氰酸酯三聚反应分子模拟与反应动力学研究

利用DMol3分子模拟软件对二苯基甲烷二异氰酸酯(MDI)、氢化二苯基甲烷二异氰酸酯(HMDI)、异佛尔酮二异氰酸酯(IPDI)3种异氰酸酯自聚反应进行了模拟计算;利用傅里叶变换红外光谱(FT-IR)对不同异氰酸酯在催化剂2,4,6-三(二甲胺基甲基)苯酚(DMP-30)作用下的三聚反应进行了跟踪,研究了不同催化剂用量、反应温度、反应时间下3种异氰酸酯的自聚反应动力学。结果表明,异氰酸酯自聚反应倾向生成稳定的六元环结构;3种异氰酸酯三聚反应均为二级反应,MDI在加入催化剂质量分数0.05%时,反应的活化能为26.1 kJ/mol,IPDI和HMDI在加入催化剂质量分数2%时,反应的活化能分别为13.5 kJ/mol和49.9 kJ/mol。     

端羟基聚丁二烯改性氰酸酯体系固化反应动力学

采用示差扫描量热法(DSC)研究了端羟基聚丁二烯(HTPB)改性双酚A型氰酸酯树脂(BADCy)体系的固化反应动力学,根据Arrhenius方程对固化过程动力学参数进行了求解,建立了固化反应动力学模型。结果表明,随着HTPB含量的增大,动态DSC固化反应放热峰向低温方向移动,说明HTPB可以催化固化反应并降低体系的反应温度。纯BADCy和BADCy/15%HTPB体系等温固化符合自催化反应模型。纯BADCy体系以及BADCy/15%HTPB体系的表观反应活化能分别为59.67 kJ/mol、56.91 kJ/mol。     

固化剂对HTPB固化过程的影响研究

为了选择端羟基聚丁二烯(HTPB)-异氰酸酯体系最佳的合成工艺,使用不同固化剂对HTPB胶粘剂进行改性,研究固化剂种类、用量及反应条件对HTPB固化的影响,研究不同反应条件下的固化体系将有助于理解和改善其固化反应并改良其力学性能。     

用过氧乙酸原位法合成环氧化端羟基聚丁二烯

用过氧乙酸原位法制备了不同环氧值的环氧化端羟基聚丁二烯,研究了反应温度,反应时间,过氧化氢与端羟基聚丁二烯(HTPB)、冰乙酸与HTPB及磺酸催化剂与HTPB质量比等对产物环氧值、羟值及开环率的影响,并用红外光谱对其结构进行了表征.结果表明,用过氧乙酸原位法可有效控制产物的开环率.最佳环氧化反应条件为反应温度50℃、反应时间7 h、过氧化氢与HTPB质量比2.50、冰乙酸与HTPB质量比0.90、磺酸催化剂与HTPB质量比0.15.     

Synthesis and Thermo-Oxidative Aging Resistance of Hydroxyl Terminated Polybutadiene Bound 2,2-Thiobis(4-methyl-6-tert-butylphenol)

A novel polymeric antioxidant HTPB-IPDI-TPH was synthesized by the reaction between 2,2-thiobis (4-methyl-6-tert-butylphenol) (TPH) and an adduct (HTPB-IPDI) from hydroxyl terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI). The effects of raw materials ratio and the reaction condition were investigated by measuring the content of the residual –NCO groups of the reactants during the reaction. The structure of HTPB-IPDI-TPH was characterized by FTIR and ¹H NMR. Thermo-oxidative aging resistance of HTPB-IPDI-TPH was evaluated by oxidation induction time (OIT) from DSC of natural rubber vulcanizates. The optimal reaction conditions between IPDI and HTPB were that the amount of dibutyltin dilaurate (DBTDL) was 0.6 wt% based on IPDI, and the temperature and time were 40°C and 270 min, respectively. The reaction conditions between TPH and HTPB-IPDI were that the molar ratio of TPH to –NCO in HTPB-IPDI was 3:1, and the amount of DBTDL was 1.6 wt% based on the total of reactants, and the temperature and time were 75°C and 360 min, respectively. Thermo-oxidative aging resistance of HTPB-IPDI-TPH was obviously superior to the corresponding low molecular counterpart (TPH) for natural rubber vulcanizates.     

HTPB-异氰酸酯体系的固化反应机理研究进展

固体推进剂和衬层配方的固化体系对其本体性能以及两者界面的黏结性能具有非常重要的影响,端羟基聚丁二烯(HTPB)和异氰酸酯是丁羟固体推进剂和衬层固化体系中最主要的组分.综述了HTPB-异氰酸酯体系的固化反应机理以及催化剂、固化剂种类和固化参数等因素对固化反应的影响.     

Kinetic study of the reaction between hydroxyl-terminated polybutadiene and isophorone diisocyanate in bulk by quantitative FTIR spectroscopy

A kinetic study of the reaction between a hydroxyl-terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI) was carried out in the bulk state by using quantitative Fourier transform infrared (FTIR) spectroscopy. The reaction is shown to obey a second-order rate law, being first order in both the HTPB and IPDI concentrations. The activation parameters obtained from the evaluation of kinetic data are ΔH‡ = 41.1 ± 0.4 kJ mol, ΔS‡ = −198 ± 2 J K⁻¹ mol⁻¹ and E_a = 43.8 ± 0.4 kJ mol⁻¹, which are quite different from the solution values. However, they are in agreement with the results obtained on propellants by torsional braid measurements. The large negative value of the activation entropy is indicative of an associative mechanism, which is in accord with the second-order rate law for the polyurethane formation. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1979–1983, 1997     

Synthesis,characterization and thermal dissociation of 2‐butoxyethanol‐blocked diisocyanates and their use in the synthesis of isocyanate‐terminated prepolymers

A series of blocked diisocyanates has been synthesized from toluene diisocyante (TDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), 4,4′‐diphenylmethane diisocyanate (MDI) and 2‐butoxyethanol. The synthesis of blocked diisocyanate adducts was confirmed by Fourier transform infrared, ¹H NMR, electron impact mass spectrometry and nitrogen analysis. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and carbon dioxide evolution were used to determine the minimum de‐blocking temperatures. De‐blocking temperatures determined by these three techniques were found to be in the order DSC > TGA > CO₂ evolution. The effect of different metal catalysts on thermal de‐blocking reaction of the blocked diisocyanates was studied, using the carbon dioxide evolution method. It was found that iron(III) oxide has the maximum catalytic activity on de‐blocking. The solubility of the blocked diisocyanate adducts was determined in different solvents. The study revealed that at 30 °C blocked IPDI and HDI adducts show better solubility than adducts based on TDI and MDI. Isocyanate‐terminated prepolymers of blocked diisocyanates and hydroxyl‐terminated polybutadiene (HTPB) were prepared. The storage stability and gelation times of the prepolymers were studied. Results showed that all the diisocyanate‐HTPB compositions are stable at 50 °C for more than three months. However, aliphatic diisocyanate‐HTPB compositions require greater gelation time than aromatic diisocyanate‐HTPB compositions at their respective de‐blocking temperatures. Copyright © 2007 Society of Chemical Industry     

Anionic waterborne polyurethane dispersions based on hydroxyl‐terminated polybutadiene and poly(propylene glycol): Synthesis and characterization

Nonpolluting systems based on anionic polyurethane aqueous dispersions were obtained. The prepolymer based on hydroxyl‐terminated polybutadiene (HTPB), isophorone diisocyanate (IPDI), poly(propylene glycol) (PPG), and dimethylolpropionic acid (DMPA) were synthesized in bulk. After neutralization with triethylamine (TEA), the anionomer prepolymer was dispersed in water, followed by a chain‐extension reaction with ethylenediamine (EDA). The prepolymers were characterized by Fourier transform infrared spectrometry (FTIR) and the average particle size of the aqueous dispersions was determined by laser light scattering (LLS). The mechanical behavior of polyurethane‐cast films and the adhesive properties of the aqueous dispersions as coatings for wood were evaluated. It was observed that an increase in the HTPB content provoked an increase in the viscosity and in the particle size of the dispersions. The tensile strength and the modulus values of the films and the adhesiveness of the coatings in wood were also increased by increasing the HTPB content. On the other hand, the elongation of the polyurethane‐cast films and the tackness of the surface coatings decreased as the HTPB was increased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 566–572, 2001     

The kinetics of the reaction of isophorone di-isocyanate with mono-alcohols

Isophorone di-isocyanate (IPDI) is used to react with hydroxyl containing prepolymers in the preparation of polyurethane elastomers, particularly with hydroxy-terminated polybutadiene (HTPB) in composite propellant systems. In the present work, the kinetics of the reaction of IPDI with monoalcohols are studied, as a model for the polyurethane systems. A gas chromatography method is used to follow the reaction, which allows direct measurement of the reaction of individual isocyanate groups. The rates of individual isocyanate groups are described by a second order equation modified to include catalysis by the urethane products. The rates of primary and secondary isocyanate groups in the two isomers of IPDI are compared. Differences between the various isocyanate groups are relatively small, and are offset by the urethane catalysis effect, so that the overall disappearance of isocyanate is roughly second order. The reaction rate of IPDI with HTPB is faster than with the model compounds, and it is suggested that this arises because there is tendency for the isocyanate to complex with the hydroxyl end groups of the polymer.     

聚磷腈的合成及其作为含能黏合剂的应用前景

聚磷腈是一类骨架由磷-氮原子交替排列的具有特殊结构和优异性能的新型功能高分子材料.综述了聚磷腈的合成方法,并对其作为含能黏合剂的应用前景进行了探讨.     

Rheo‐kinetic evaluation on the formation of urethane networks based on hydroxyl‐terminated polybutadiene

Rheo‐kinetic studies on bulk polymerization reaction between hydroxyl‐terminated polybutadiene (HTPB) and di‐isocyanates such as toluene‐di‐isocyanate (TDI), hexamethylene‐di‐isocyanate (HMDI), and isophorone‐di‐isocyanate (IPDI) were undertaken by following the buildup of viscosity of the reaction mixture during the cure reaction. Rheo‐kinetic plots were obtained by plotting ln (viscosity) vs. time. The cure reaction was found to proceed in two stages with TDI and IPDI, and in a single stage with HMDI. The rate constants for the two stages k₁ and k₂ were determined from the rheo‐kinetic plots. The rate constants in both the stages were found to increase with catalyst concentration and decrease with NCO/OH equivalent ratio (r‐value). The ratio between the rate constants, k₁/k₂ also increased with catalyst concentration and r‐value. The extent of cure reaction at the point of stage separation (x_i) increased with catalyst concentration and r‐value. Increase in temperature caused merger of stages. Arrhenus parameters for the uncatalyzed HTPB‐isocyanate reactions were evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1869–1876, 2001     

Issues Related with Pot Life Extension for Hydroxyl‐Terminated Polybutadiene‐Based Solid Propellant Binder System

Extension of the pot life for hydroxyl‐terminated polybutadiene (HTPB) based propellant binder systems was attempted through employing a bicurative system comprising of toluene‐di‐isocyanate (TDI) and isophorone‐di‐isocyanate (IPDI). Pot life characteristics were studied through evaluating curing kinetics for the HTPB‐bicurative binder formulations. Curing kinetics were studied through viscosity buildup during the cure reaction and estimation of the rate constants for viscosity build‐up. Introduction of IPDI slowed down the curing process, but at the same time, has not adversely affected the mechanical characteristics. One of the discouraging factors in adopting IPDI as curative is the poor interface characteristics between liner and insulator of the solid propellant grains, and it has been proposed that the root cause for the same is the permeation of IPDI through the insulator. Quantification of such permeation was attempted from the numerical values for cross‐link density evaluated for various binder compositions. Remedy for poor interface characteristics is suggested in this study.     

异佛尔酮二异氰酸酯扩链合成聚丁二酸丁二醇酯的研究

以异佛尔酮二异氰酸酯(IPDI为)扩链剂对低分子量的聚丁二酸丁二醇(酯PBS进)行扩链,研究了扩链剂用量、反应时间、反应温度对PBS分子量的影响,并探讨了扩链反应的机理。结果表明:合成PBS的最佳条件是IPDI用量1.0%,反应温度140℃,常压反应60min;扩链反应时,IPDI的异氰酸酯基团与PBS分子链端的羟基反应生成氨基甲酸酯,将PBS预聚体进行偶联处理,从而使PBS的分子量显著提高。