端羟基聚丁二烯中羟基类型的NMR研究进展

介绍了核磁共振（NMR）研究端羟基聚丁二烯（HTPB）中羟基类型的进展,给出了自由基聚合法合成HTPB中涉及的反应机理,总结了HTPB的羟基类型和力学性能的相互关系,并为解决HTPB指标相同、批次不同而性能有很大差异的问题提供了一个基本思路和方法。     

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.     

高顺式端羟基聚丁二烯的合成研究进展

介绍了高顺式端羟基聚丁二烯(HTPB)分子的结构特点,指出高顺式HTPB与普通HTPB相比,其分子主链的柔顺性更好,使HTPB获得更低的玻璃化转变温度,因此提高了 HTPB的耐低温性,扩宽了 HTPB的使用温度下限,可较大程度增加其固体推进剂在极端寒冷条件下的使用范围.通过比较几种合成方法,认为丁二烯单体聚合法目前合成...     

阴离子法合成端羟基聚丁二烯研究进展

介绍了阴离子法端羟基聚丁二烯(HTPB)的特点和应用,以及国外阴离子法生产HTPB的工业化情况。详细叙述了阴离子法HTPB的国内外研究进展情况,重点介绍了羟基保护的阴离子法合成HTPB的方法。     

负离子聚合法合成端羟基聚丁二烯与自由基法端羟基聚丁二烯的性能对比

以硅烷保护羟基的烷基锂为引发剂,采用负离子聚合法合成了端羟基聚丁二烯(HTPB),通过核磁共振氢谱、傅里叶变换红外光谱、凝胶渗透色谱和差示扫描量热法表征了HTPB的微观结构、分子量分布、官能度及玻璃化转变温度(Tg),研究了HTPB胶片的拉伸性能,并与自由基法HTPB进行了对比。结果表明,负离子法HTPB的1,4-结构摩尔分数约为90%,比自由基法HTPB高约12%,分子量分布小于1.1,低于自由基法HTPB,平均官能度比自由基法HTPB更接近理想值2,Tg为-88.3℃,较自由基法HTPB低9.7℃;负离子法HTPB胶片的拉伸强度与自由基法HTPB胶片相近,但扯断伸长率比自由基法HTPB胶片提高约74%。     

端羟基聚丁二烯主链改性研究进展

简要介绍了目前合成端羟基聚丁二烯(HTPB)的自由基聚合法和阴离子聚合法,并简述这2种合成方法的优缺点。重点叙述了HTPB主链改性研究进展,通过对 HTPB 主链中的双键进行改性或利用嵌段共聚技术,可向HTPB主链上引入新的特征基团或某些功能性链段,从而赋予改性后的HTPB不同的性能,拓宽其应用领域。     

韦氏法测定端羟基聚丁二烯碘值的探究

采用韦氏法研究了端羟基聚丁二烯(HTPB)样品的碘值测定,对其实验条件,如称样量、反应时间、液封等进行了探究。结果表明,在HTPB样品碘值的测定过程中,要用碘化钾溶液密封反应瓶口,最优称样量为0.3 g,反应时间为100 min。该法具有较高的精密度,且存放30 d后样品的检测结果重现性的相对标准偏差为1.32%。     

端羟基聚丁二烯端基改性研究进展

简述了端羟基聚丁二烯(HTPB)的端基改性(如将端羟基转化为端羧基、端氨基、端异氰酸酯基、端环氧基、端叠氮基、端乙烯基和端炔基等)及其研究进展。研究发现端环氧基聚丁二烯、端炔基聚丁二烯和端乙烯基聚丁二烯具有更好的应用价值,另外,随HTPB嵌段改性研究不断深入,其嵌段共聚醚也必将具有更广阔的应用前景。     

端羟基聚丁二烯液体橡胶制备技术的研究进展

对端羟基聚丁二烯（HTPB）液体橡胶的性能特点和应用领域等进行了概述,综述了HTPB的制备方法及其特点,同时对各类方法进行了对比,并提出了利用烯烃复分解法制备HTPB的优势以及烯烃复分解反应的特点,对其未来的发展方向进行了展望。     

多羟基聚丁二烯的合成研究

采用过氧甲酸原地法对端羟基聚丁二烯(HTPB)进行环氧化及开环,合成了多羟基聚丁二烯(PHPB)。通过产品的粘度和羟值详细考察了反应温度、反应时间、原料配比等因素对PHPB合成反应的影响。结果表明,最佳合成工序条件为:反应温度60℃,反应时间4h,H2O2与双键的物质的量比为0.05,甲酸与双键的物质的量比为0.30。     

Viscoelastic behavior of hydroxyl terminated polybutadiene containing glycerin

Hydroxyl terminated polybutadiene (HTPB) is widely used as a propellant binder. A plasticizer is usually added to improve the processing properties, the mechanical properties, and the burning characteristics of the propellant. Glycerin was found to be an effective additive to improve these properties. The glycerin/HTPB blend was hard enough to act as a binder for the composite propellant when the glycerin/HTPB mole ratio was less than 10. Only a small quantity of glycerin was incorporated into the network structure of the cured HTPB. Most of the added glycerin physically entered the voids in the network of the cured HTPB. Addition of a small quantity of glycerin (mole ratio less than 0.1) significantly altered the network density and the viscoelastic properties of the blends. The properties were only slightly dependent on the amount of the added glycerin in the mole ratio range of 0.1–10. The dangling ends were formed in the HTPB network by the addition of glycerin and the network structure was loosened, thereby enhancing the mobility of the chain segment. The viscoelastic properties of the blends followed the time‐temperature superposition principle, and the properties were estimated accurately by the Williams‐Landel‐Ferry approach. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Modification of epoxy resin by isocyanate‐terminated polybutadiene

Hydroxy‐terminated polybutadiene was functionalized with isocyanate groups and employed in preparation of a block copolymer of polybutadiene and bisphenol A diglycidyl ether (DGEBA)‐based epoxy resin. The block copolymer was characterized by Fourier transform infrared (FTIR) spectroscopy and size‐exclusion chromatography (SEC). Cured blends of epoxy resin and hydroxy‐terminated polybutadiene (HTPB) or a corresponding block copolymer were characterized by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMTA), and scanning electron microscopy (SEM). All modified epoxy resin networks presented improved impact resistance with the addition of the rubber component at a proportion up to 10 wt % when compared to the neat cured resin. The modification with HTPB resulted in milky cured materials with phase‐separated morphology. Epoxy resin blends with the block copolymer resulted in cured transparent and flexible materials with outstanding impact resistance and lower glass transition temperatures. No phase separation was discernible in blends with the block copolymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 838–849, 2002     

Curing of carboxyl terminated polybutadiene with epoxide. Effect of additives

An investigation has been made of curing of carboxyl terminated polybutadiene with the epoxide EPON 812 and with a chromium chelate as catalyst. The effect on curing of some additives, ammonium perchlorate (AP) and boron, has been measured at three temperatures 323, 343, and 363 K. The results show that the polymer without additive and with AP cures very well. Addition of boron to the polymer decreases the curing reaction. Addition of boron and AP together inhibits the curing reaction almost completely.     

A novel polyurethane sealant based on hydroxy‐terminated polybutadiene

A novel two component polyurethane sealant has been prepared. Component A, known as prepolymer, is synthesized by capping hydroxy‐terminated polybutadiene (HTPB) with toluene diisocyanate. Component B, known as hardener, comprises of a polyol (polyoxypropylene triol) as crosslinker and 4,4′‐diamino‐3,3′‐dichlorodiphenylmethane (DADCDPM) and 4,4′‐diamino‐3,3′‐dichlorotriphenylmethane (DADCTPM) as chain extenders and fillers. Evaluation of mechanical properties and aging studies indicate that the sealant has excellent mechanical properties and stability in different environment. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 884–890, 2006     

Derivatization of carboxyl‐terminated polybutadiene for determining relative functionality distribution

A new and highly efficient method for determining relative carboxyl group distribution in carboxyl‐terminated polybutadiene has been developed using practical synthetic and analytical techniques. Using oxalyl chloride, samples of carboxyl‐terminated polybutadiene were rapidly transformed to acid chlorides that were then chemically derivatized with benzyl alcohol, 4‐nitrobenzyl alcohol, and 3,5‐dinitrobenzyl alcohol. This provided quick and quantitative conversion to the corresponding benzyl ester derivatives. Each new derivative was fully characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. The benzyl ester modified polymers were investigated in detail to determine their relative carboxyl group concentrations. To do this, gel permeation chromatography combined with ultra violet/refractive index dual detection was employed. The 4‐nitrobenzyl ester, having the highest extinction factor at 270 nm provided the best UV data for analysis. The ultra violet/refractive index data of four separate polymer samples were plotted as a function of molecular weight. The data were compared with a theoretical plot (carboxyl group = two for all molecular weights) to illustrate the relative carboxyl concentration over the entire molecular weight range. Supplemental characterization of the 4‐nitrobenzyl modified polymer was carried out using matrix‐assisted laser desorption ionization coupled with time of flight mass spectrometry. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

高1,4-结构含量双端羟基聚丁二烯的合成与表征

以含硅氧烷的有机锂引发丁二烯负离子聚合,在30℃反应20h后通过环氧乙烷羟基化及酸解脱除保护基合成了双端羟基聚丁二烯(DHTPB),并采用凝胶渗透色谱、傅里叶变换红外光谱、核磁共振、羟值滴定对其进行了表征。结果表明,在不加入四氢呋喃时DHTPB的1,4-结构摩尔分数可达92.1%,得到的DHTPB相对分子质量大小可控、分子量分布不超过1.12、官能度接近2.00。     

Effect of temperature on the rheological behavior of hydroxyl terminated polybutadiene propellant slurry

Hydroxyl terminated polybutadine (HTPB) based composite solid propellants have gained prominence in advanced missiles and launch vehicles including the Space Shuttle's Inertial Upper Stage (IUS) motor (1). To achieve a blow-hole free well performing casting, the knowledge of the processability characteristics and rheological behavior of the propellant slurry are of vital interest. In our earlier communication (2) we had discussed the effect of compositional aspects, namely solid loading, oxidizer particle size distribution, and aluminum content on the rheology of HTPB propellant. For an optimized solid loading with corresponding oxidizer particle size distribution and aluminium content, the effect of temperature on the processability and the pot life are studied and reported in this paper. This study establishes the fact that the HTPB slurry shows a complex rheological behavior having thixotropy and yield stress. The thixotropic index and yield stress show minimum values at an optimum temperature. This optimum temperature shifts to lower values as time elapses. Activation energies have been calculated for the cure reaction based on yield stress and viscosity. It is observed that the activation energy values reach asymptotic levels after about three hours of curative addition.     

Blends of modified epoxy resin and carboxyl‐terminated polybutadiene. I

Six blend samples were prepared by the physical mixing of epoxidized resole (EDR) with different weight ratios of carboxyl‐terminated polybutadiene (CTPB) liquid rubber ranging from 0 to 25 wt % in intervals of 5 wt %. The formation of various reaction products during the curing of unblended EDR and CTPB‐blended EDR were studied with Fourier transform infrared spectroscopy. The curing time at 100°C for the blend sample containing 15 wt % CTPB was the least among all of the blend samples. This blend sample, also, showed the highest initial degradation temperature, as obtained from thermogravimetric analysis thermograms, which indicated that it was the most thermally stable matrix system. The films of coatings based on the blend of EDR with 15 wt % CTPB offered the highest resistance toward different concentrations of acids and alkalis compared to the films having 5, 10, 20, and 25 wt % CTPB in the EDR/CTPB blends. Solvents showed almost the same behavior as acids and alkalis for these films except for hydrocarbon solvents such as mineral turpentine oil, toluene, and xylene. The resistance toward these solvents was poor and slightly inferior to those found with EDR unblended with CTPB. The tensile, flexural, and impact strengths of the molded specimens derived from the EDR/CTPB blends initially increased up to 15 wt % CTPB addition in the blend and then decreased, whereas the elongation at break remained constant for all blend compositions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1802–1808, 2006     

端羟基聚丁二烯/聚氨酯/有机蒙脱土纳米复合材料的制备及性能

以双羟乙基甲基氢化牛脂基氯化铵为插层剂,采用单体插层法制备了端羟基聚丁二烯(HTPB)、聚氨酯(PU)和有机蒙脱土(OMMT)纳米复合材料.当OMMT为3质量份时,HTPB/PU/OMMT纳米复合材料的T型剥离强度是HTPB/PU复合材料的2.58倍.X射线衍射和透射电镜分析表明,OMMT在HTPB/PU/OMMT纳米复合材料中呈剥离状态.     

Terminal functionalized hydroxyl‐terminated polybutadiene: An energetic binder for propellant

We report the functionalization of hydroxyl terminated polybutadiene (HTPB) backbone by covalently attaching 1‐chloro‐2, 4‐dinitrobenzene (DNCB) at the terminal carbon atoms of the HTPB. The modification of the HTPB by the DNCB does not alter the unique physico–chemical properties and the microstructure of the parent HTPB. IR, ¹H‐NMR, ¹³C‐NMR, size exclusion chromatography (SEC) and absorption spectroscopy studies prove that the DNCB molecules are covalently attached to the terminal carbon atoms of the HTPB. The π electron delocalization owing to long polymer chain, strong electron withdrawing effect of the DNCB molecule are the major driving forces for the covalent attachment of the DNCB at the terminal carbon atom of the HTPB. We are the first to observe the existence of intermolecular hydrogen bonding between the terminal hydroxyl groups of the HTPB. IR study shows that the attached DNCB molecules at the terminal carbon atoms of the HTPB breaks the intermolecular hydrogen bonding between the HTPB chains and forms a hydrogen bonding between the NO₂ groups of the DNCB and the OH groups of the HTPB. Absorption spectral study of the modified HTPB indicates the better delocalization of π electron of butadiene due to the strong electron withdrawing effect of the DNCB molecules. Theoretical calculation also supports the existence of hydrogen bonding between the OH and NO₂ groups. Theoretical calculation shows that the detonation performance of both the DNCB and the HTPB‐DNCB are promising. HTPB‐DNCB is the new generation energetic binder which has potential to replace the use of HTPB as binder for propellant.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009