Curing characteristics of glycidyl azide polymer‐based binders

The curing of a glycidyl azide polymer (GAP) with a triisocyanate, Desmodur N‐100, was followed by measuring the hardness and viscosity. The thermal behavior of the cured samples were investigated by a differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). Curing causes an increase in the glass transition temperature of GAP. The T_g of gumstocks also increases with an increasing NCO/OH ratio while the decomposition temperature remains practically unchanged. The ultimate hardness of the cured samples increases with an increasing NCO/OH ratio. The binder with a NCO/OH ratio of 0.8 was found to provide the most suitable thermal and physical characteristics for composite propellant applications. The increase in the glass transition temperature of gumstocks upon curing can be compensated by using a 1:1 mixture of bis‐2,2‐dinitropropyl acetal and formal as the plasticizer. The T_g value of gumstocks can be decreased to −46.7°C by adding 25% b.w. of a plasticizer which does not have any significant effect on the decomposition properties of the gumstocks. Furthermore, a remarkable decrease in the ultimate hardness of the gumstocks is achieved upon addition of a plasticizer, while the curing time remains almost unaffected. The addition of dibuthyltin dilaurate as a catalyst reduces the curing time of the gumstocks from 3 weeks to 5–6 days at 60°C. Use of the curing catalyst also results in the hardening of the gumstocks. The decomposition properties of the gumstocks remain practically unchanged while a noticeable increase is observed in the glass transition temperature with an increasing concentration of the catalyst. This can also be compensated by a reverse effect of the plasticizer. The gel time, an important parameter which determines the pot life of a propellant material, can be measured by monitoring the viscosity of the mixture, which shows a sharp increase when gelation starts. The addition of a curing catalyst shortens the gel time remarkably. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 65–70, 2001     

Molecular-beam mass-spectrometric study of the flame structure of composite propellants based on nitramines and glycidyl azide polymer at a pressure of 1 MPa

A study was performed of the chemical and thermal structure of flames of model composite propellants based on cyclic nitramines (RDX and HMX) and an active binder (glycidyl azide polymer) at a pressure of 1 MPa. Propellant burning rates were measured. The chemical structure of the flame was studied using molecular-beam mass spectrometry, which previously has not been employed at high pressures. Eleven species (H₂, H₂O, HCN, N₂, CO, CH₂O, NO, N₂O, CO₂, NO₂, and nitramine vapor) were identified, and their concentration profiles, including the composition near the burning surface were measured. Two chemical-reaction zones were observed. It was shown that flames of nitramine/glycidyl azide polymer propellants are dominated by the same reactions as in flames of pure nitramines. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 6, pp. 48–57, November–December, 2006.     

GAP黏合剂胶片力学性能的影响因素

应用静态拉伸、动态力学和核磁交联密度仪等方法研究了增塑剂正丁基硝氧乙基硝胺(BuNENA)、固化剂多异氰酸酯(N-100)和甲苯二异氰酸酯(TDI)、交联剂三羟甲基丙烷(TMP)、扩链剂1,4-丁二醇(BDO)对改性聚叠氮缩水甘油醚(GAP)黏合剂胶片力学性能的影响。结果表明,增塑比(Pl/Po)由0.6增至1.6,GAP黏合剂胶片的拉伸强度由0.22MPa降至0.06MPa,交联密度由6.7×10-5 mol/mL降至4.9×10-5 mol/mL,延伸率略有提升。调节N-100/TDI双固化体系,可提高GAP黏合剂胶片的强度和延伸率,当N-100和TDI的固化参数分别为0.36、1.44时,胶片强度和延伸率分别为0.24MPa和558.7%。加入质量分数0.5%的交联剂TMP可使GAP黏合剂胶片强度升至0.32MPa,延伸率降至278.5%。加入质量分数0.1%的扩链剂BDO,可使胶片强度和延伸率分别达到0.33MPa和323.1%。     

GAP高能低特征信号推进剂的燃烧性能调节

研究了硝胺种类、固体组分含量和粒度、增塑剂与GAP的增塑比及燃速催化剂对GAP高能低特征信号推进剂在11~19MPa下燃烧性能的影响。结果表明,当HMX取代推进剂样品中的RDX时,推进剂的燃速较高,压强指数从0.72降至0.63;在AP和HMX总质量分数为67.5%的条件下,随着AP质量分数由5%增至30%,推进剂燃速逐渐增大,压强指数由0.82降至0.45;减小AP粒度以及在配方中添加燃速催化剂或调节过渡金属化合物J1/J2的配比,可较大幅度地增加推进剂燃速和降低压强指数,其中,J1与J2总质量分数为3%,二者质量比为2∶1和1∶1时,推进剂的压强指数较小,分别为0.50和0.48;随着HMX粒度减小及增塑剂与GAP黏合剂的增塑比的降低,推进剂的燃速和压强指数降低。     

Kinetics of polyurethane formation between glycidyl azide polymer and a triisocyanate

Kinetics of the polyurethane formation between glycidyl azide polymer (GAP) and a polyisocyanate, Desmodur N‐100, were studied in the bulk state by using quantitative FTIR spectroscopy. The reaction was followed by monitoring the change in intensity of the absorption band at 2270 cm^?1 for NCO stretching in the IR spectrum, and was shown to obey second‐order kinetics up to 50% conversion. The activation parameters were obtained from the evaluation of kinetic data at different temperatures in the range of 50–80°C. The enthalpy and entropy of activation were found to be ΔH^? = 44.1 ± 0.5 kJ · mol^?1 and ΔS^? = ?196 ± 2 J · mol^?1l · K^?1, respectively. Dibutyltin dilaurate (DBTDL) was used as the curing catalyst. The kinetic study of the polyurethane formation between GAP and Desmodur N‐100 showed that the reaction is enormously speeded up in the presence of the catalyst, and the reaction obeys second‐order kinetics, provided that the catalyst concentration is kept constant. An investigation on the rate of the catalysed reaction depending on the catalyst concentration provided the order of the reaction, with respect to the DBTDL catalyst concentration, and the rate constant for the catalytic pathway of the reaction. The rate constant for the catalytic pathway was established to be 4.37 at 60°C, while the uncatalyzed reaction has a rate constant of 3.88 × 10^?6 L · mol^?1 · s^?1 at the same temperature. A rate enhancement factor of 23 was achieved by using 50 ppm catalyst. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 918–923, 2001     

Rheological and thermal properties of glycidyl azide polyol‐based energetic thermoplastic polyurethane elastomers

The purpose of this study was to investigate the effects of polyol on glycidyl azide polyol (GAP)‐based energetic thermoplastic polyurethane elastomers (ETPEs). Briefly, a series of GAP/polyol‐based ETPEs (GAP/polyol ETPEs) with different copolyol ratios and hard segment contents were synthesized using GAP‐diol with common polyol and 4,4‐methylenebis(phenylisocyanate)‐extended 1,5‐pentanediol as soft and hard segments, respectively, by solution polymerization in dimethylformamide. The three types of polyols used were poly(tetramethylene ether) glycol (PTMG), polycarbonate‐diol (PCL‐diol) and polycaprolactone‐diol (PCD‐diol). The synthesized GAP/polyol ETPEs were identified and characterized using Fourier transform infrared and ¹H NMR spectroscopy, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and rheometric mechanical spectrometry. For GAP/PCL ETPEs with lower hard segment content, DSC results showed that the GAP segment failed to interact with either the PCL segment or PCL melting. In addition, the results of DMA showed that the presence of PCL segments in ETPEs improved the storage modulus below the melting temperature of the PCL block. Further, the crystalline PCL segments were attributed to reinforcing the ETPEs in a manner similar to that of the hard domain. As the hard segment content increased in the GAP/polyol ETPEs, both GAP/PTMG ETPEs and GAP/PCL ETPEs exhibited microphase separation transitions, while rheological experiments demonstrated a sudden decrease in complex viscosity in neighboring microphase separation transitions. © 2012 Society of Chemical Industry     

聚叠氮缩水甘油醚的合成与改性研究进展

聚叠氮缩水甘油醚(GAP)是国内外重点研究的含能粘合剂之一。该文综述了GAP的合成研究进展,重点介绍了高相对分子质量GAP、支化GAP和等规GAP的合成。针对GAP反应活性低的特点,介绍了GAP的多种端基改性方法。GAP的无规、嵌段共聚物改善了GAP粘合剂的性能,GAP与其他粘合剂的互穿及共混,为GAP在推进剂中的应用提供了广阔前景。引用文献37篇。     

GAP型交联改性双基推进剂黏合剂的力学性能

将GAP与异氰酸酯预聚后引入双基推进剂黏合剂中,研究了固化剂种类、R值、固化催化剂二月桂酸二丁基锡(T12)的含量和增塑比对黏合剂的交联网络结构参数RNB值和力学性能的影响。结果表明,随着R值以及(T12)含量的增大,黏合剂的RNB值增大。在与NC中活性-OH交联反应时,TDI的反应活性比IPDI的高。GAP-TDI/NC/NG胶片的最大抗拉强度和断裂延伸率分别可达1.09MPa和202.12%,Tg最低为-42.66℃。     

Synthesis of poly(methyl methacrylate‐g‐glycidyl azide) graft copolymers using N,N‐dithiocarbamate‐mediated iniferters

A glycidyl azide polymer with pendent N, N‐diethyl dithiocarbamate groups (GAP‐DDC) was prepared by the reaction of poly(epichlorohydrin) (PECH) with pendent N, N‐diethyl dithiocarbamate groups (PECH‐DDC) and sodium azide (NaN₃) in dimethylformamide (DMF). It was then used as a macro‐photoinitiator for the graft polymerization of methyl methacrylate (MMA). Photopolymerization was carried out in a photochemical reactor at a wavelength greater than 300 nm. Conversion was determined gravimetrically and first‐order time conversion plot for the polymerization system showed linear increase with the polymerization time indicating that polymerization proceed in controlled fashion. The molecular weight distribution (M_w/M_n) was in the range of 1.4–1.6 during polymerization. The formation of poly(methyl methacrylate‐g‐glycidyl azide) (PMMA‐g‐GAP) graft copolymer was characterized by gel permeation chromatography, FT‐IR spectroscopy, Thermogravimetric analysis, and differential scanning calorimetry. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

端叠氮基聚叠氮缩水甘油醚的合成与热性能

以不同多元醇为起始剂,环氧氯丙烷经阳离子开环聚合得到不同结构的端羟基聚环氧氯丙烷(PECH-OH),将其端羟基进行磺酰化改性得到端磺酸酯基聚环氧氯丙烷(PECH-OTS),随后的叠氮化反应中叠氮基同时取代PECH-OTS的端磺酸酯基和侧基中的氯得到目标产物。用IR、GPC、TG和DSC对不同结构的GAPA进行了表征。结果表明,GAPA-2、GAPA-3和GAPA-4的数均相对分子质量分别为810、830和1190,玻璃化转变温度分别为-67.5、-63.8和-58.6℃,端叠氮基聚叠氮缩水甘油醚(GAPA)的热分解可分为相对独立的叠氮基热分解(250℃)和聚醚主链热分解。     

新型高能聚合物GAP的热分解和燃烧

简要回顾了GAP的研究历程及应用情况，介绍了有关GAP的特点及研究现状，着重阐述了GAP热分解及燃烧过程的特点，给出了目前比较先进的实验方法及手段，如色谱—质谱联用、热解质谱、分子束质谱、红外激光、紫外激光、CO2激光诱导热解等，可供进一步研究GAP参考。     

Thermal interaction between polymer‐based composite friction materials and counterfaces

Attempts have been made to improve the performance of polymeric composite friction materials for eliminating undesirable mechanical and thermal effects on the opposing surfaces. Elastic compression modulus and thermal conductivity of the moulded friction materials were found to be the most effective parameters upon the thermal interaction between the disc and brake pad. Effects of elastic modulus on temperature accumulation of the interface have also been studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 364–369, 2001     

含能增塑剂研究进展(续)

(接上期第 2 5页 )3　 2种含能基团3.1　硝酸酯基 +硝基在 2 0 0 1年第 32届火炸药年会上瑞典国防研究所的DetlefDrees将 2 ,2 二硝基 1,3 二硝氧基丙烷(NPN) [2 7] 与其他 2种增塑剂进行比较 ,结果见表 5。表 5　NPN与其他增塑剂性能比较性能Bu NENABDNPF/ANPN　相对分子质量 2 0 7　 42 6　 2 5 6　氧平衡 / % -10 4.3　 -5 7.5　 12 .5　密度 / (g·cm- 3) 1.2 2　 1.3 9　 1.66　熔点 /℃ -9　 -15　Tg(纯物质 ) /℃ -83 .5　 -65 .2　 -81.5　Tg(PNIMMO与增塑剂　质量比为 5 0∶5 0 ) /℃ -70 .1　 -4 8.5　 -64 .6　粘…     

GAP基含能热塑性弹性体的合成与表征

以聚叠氮缩水甘油醚(GAP)为软段,1,4-丁二醇(BDO)和4,4′-二苯基甲烷二异氰酸酯(MDI)为硬段,采用熔融预聚体法合成了GAP基含能热塑性弹性体(ETPE)。研究了扩链剂加料方式、催化剂用量、异氰酸酯指数、硬段含量等因素对弹性体力学性能的影响。采用傅里叶变换红外光谱(FT-IR)、凝胶渗透色谱(GPC)、热台显微镜、差示扫描量热(DSC)、热重分析(TG)表征了ETPE的性能。结果表明,采用恒速滴加扩链剂方法合成的ETPE具有良好的热稳定性和力学性能。当催化剂质量分数为0.6‰,异氰酸酯指数(R)为0.98,硬段质量分数(Y)为35%时,热塑性弹性体的数均相对分子质量为52 312,软化点为96℃,拉伸强度为14.52MPa,断裂伸长率为518.78%。     

Synthesis,spectral and DSC analysis of glycidyl azide polymers containing different initiating diol units

Glycidyl azide polymers (GAPs), containing different diol units, were prepared by treating the corresponding poly(epichlorohydrin)s (PECHs) with sodium azide in DMF solvent at 110°C for 8–10 h. The poly(epichlorohydrin)s containing different diol units were synthesized by the polymerization of epichlorohydrin using borontrifluoride etherate as initiator in the presence of a small amount of low molecular weight diols. The formation of these PECHs was confirmed by IR spectroscopy. The nature of terminal hydroxyl group present in the polymer chain was confirmed by proton NMR spectroscopy. The structure of GAPs containing different initiating diol units was confirmed by UV, IR, and proton NMR spectral analysis. Thermal properties of the GAPs were evaluated using differential scanning calorimetry; the stabilities and glass‐transition temperatures of the GAPs varied according to the initiating diol unit present in the polymer chains. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2157–2163, 2004     

Viscoelastic properties and characterization of inorganic particulate‐filled polymer composites

To identify effects of glass bead (GB) content on the dynamic mechanical properties of filled low‐density‐polyethylene (LDPE) composites, the storage modulus, loss modulus, glass transition temperature, and mechanical damping of these composites were measured using a Du Pont dynamical mechanical analysis instrument in temperature range from ?150 to 100°C. It was found that the storage modulus increased nonlinearly with an increase of the GB volume fraction. On the basis of Eshelby's method and Mori's work, an equation describing the relationship between the relative storage modulus (E′_R) and filler volume fraction for polymeric composites was proposed, and the E′_R of LDPE/GB composites were estimated by means of this equation at temperatures of ?25, 0, and 25°C, and the calculations were compared with the experimental data, good agreement was showed between the predictions and the measured data. Furthermore, this equation was verified by the experimental from Al(OH)₃ filled EPDM composites at glassy state reported in a reference. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Reactive Energetic Plasticizers for Energetic Polyurethane Binders Prepared via Simultaneous Huisgen Azide‐Alkyne Cycloaddition and Polyurethane Reaction

Reactive energetic plasticizers (REPs) for use in glycidyl azido polymer (GAP) based polyurethane (PU) energetic binders were investigated. These REPs consisted of an activated terminal alkyne group that was expected to give rise to Huisgen azide‐alkyne 1,3‐dipolar cycloaddition within the specific pot life for a PU formulation to prevent the migration of plasticizers, and with a gem‐dinitro group as an energy resource. A quantitative miscibility investigation between the plasticizers and uncured GAP showed that REPs exhibited better miscibility than conventional energetic plasticizers. The plasticization effect of the REPs on the GAP prepolymer with respect to the reduction of the viscosity illustrated REPs can effectively reduce the viscosity of the GAP prepolymer from 6,015 cP to 150–240 cP at the processing temperature when 50 wt‐% of REP was added. A comparison of the click reactivity and activation energies (E_a) of REPs and GAP prepolymer elucidated that the reactivity of azide‐alkyne cycloaddition depended on the dipolarophilicity of REPs which could be controlled by adjusting the length of methylene spacer between electron‐withdrawing groups (EWG) and neighboring alkynes in REPs. Thermogravimetric analysis manifested REP/GAP‐based PU binders maintained the thermal stability of the control GAP‐based PU binder. The mechanical properties and impact insensitivity of the GAP‐based PU binders were also improved by the incorporation of REPs.     

Porous properties of poly(glycidyl methacrylate‐co‐trimethylolpropane trimethacrylate) resins synthesized by suspension polymerization

Porous copolymer beads of 2,3‐epoxypropyl methacrylate (glycidyl methacrylate, GMA) crosslinked with 2‐ethyl‐2‐(hydroxymethyl)‐propan‐1,3‐diol trimethacrylate (trimethylolpropane trimethacrylate, TRIM) were prepared with toluene and octan‐2‐one as porogens by suspension polymerization. With an increase in the ratio of porogen to monomer, the total pore volume of poly(GMA‐co‐TRIM) increases significantly, whereas the surface area hardly changes. The total pore volume also depends on the nature of the porogen, exhibiting a maximum at the larger GMA contents in the monomer mixture of 50% v/v with octan‐2‐one and of 60% v/v with toluene, compared to that at the GMA content of 25% v/v with a 9/1 v/v mixture of cyclohexanol and dodecan‐1‐ol [Verweij, P. D.; Sherrington, D. C. J Mater Chem 1991, 1 (3), 371]. The surface area decreases significantly with an increase in the ratio of GMA to TRIM, almost regardless of the nature of the porogen. The porous properties of poly(GMA‐co‐TRIM) was well explained on the basis of phase separation, particularly taking into account not only the solubility parameters of the resulting polymer network and porogen but also the rigidity of TRIM. The porous poly(GMA‐co‐TRIM) may be a promising polymer matrix of novel materials for separation of boron isotopes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2374–2381, 2002