硝化甘油与高分子黏合剂混合体系相互作用的理论研究

运用MO-PM3方法计算了硝化甘油(NG)与高分子黏结剂聚乙二醇(PEG)、端羟基聚丁二烯(HTPB)、缩水甘油叠氮基聚醚(GAP)、3-叠氮甲基-3-甲基环氧丁烷聚合物(AMMO)和3,3-双(叠氮甲基)环氧丁烷聚合物(BAMO)的混合模型体系的几何结构(聚合度n=1,2,3,4),由色散能校正电子相关近似求得其分子间相互作用能(△E).结果表明,当n=4时,5个混合体系的相互作用能为-49～-60kJ/mol.除GAP和BAMO以外,当n值增大时,混合体系的相互作用能增加.混合体系中,两个子体系的原子与原子之间最短距离为0.270～0.340nm.     

丁三醇三硝酸酯与高分子黏合剂的相互作用

运用半经验分子轨道理论PM3方法计算丁三醇三硝酸酯(BTTN)分别与聚乙二醇(PEG)、端羟基聚丁二烯(HTPB)、缩水甘油叠氮基聚醚(GAP)、3-叠氮甲基-3-甲基环氧丁烷聚合物(AMMO)和3,3-双(叠氮甲基)环氧丁烷聚合物(BAMO)等高分子黏合剂所形成的混合体系模型物,求得稳定几何构型.由色散能校正电子相关,求得其结合能.计算结果表明,高分子黏合剂HTPB、AMMO与BTTN的结合能(绝对值)随着高分子聚合度的增加而增大,而BAMO、GAP、PEG与BTTN间的结合能呈不同规律.GAP、AMMO和BAMO与BTTN的结合能略大于HTPB和PEG.     

含能粘合剂合成研究新进展(续一)

<正> (上接第4期)4取代环氧丁烷聚合物合成4.1取代环氧丁烷的可控聚合3,3-双(叠氮甲基)环氧丁烷(BAMO)和3-叠氮甲基-3-甲基环氧丁烷(AMMO)均聚和共聚醚以及与四氢呋喃的共聚醚是目前人们研究最为深入的叠氮甲基取代环氧丁烷聚合物。与取代缩水甘油醚单体比较,尽管环氧丁烷和环氧丙烷母体的环张力大致相同,但在阳离子开环聚合过程中,后者存在严重的链“回咬”副反应,生成环齐聚物,使得最终聚合产物的相对分子质量和官能度难以提高。可利用环氧丁烷     

BAMO/AMMO三嵌段共聚物的合成、表征及热分解动力学

以三氟化硼.乙醚/1,4丁二醇作引发体系,利用阳离子开环共聚合的方法合成出3,3′-双叠氮甲基环氧丁烷/3-叠氮甲基-3′-甲基环氧丁烷(BAMO/AMMO)三嵌段共聚物。用FTIR、1HNMR和GPC对共聚物的结构和相对分子质量进行了表征,用DSC测定了共聚物的玻璃化转变温度。结果表明,合成的BAMO/AMMO三嵌段共聚物的相对分子质量可控、且分布窄,并具有含能热塑性弹性体的性质。同时用Vyazovkin的非线性无模型函数方法研究其热分解动力学,得到叠氮基团的分解活化能约为150kJ/mol。三嵌段共聚物在叠氮基团分解之后形成了交联网络结构。     

BAMO的能量研究

3,3-双(叠氮甲基)环氧丁烷(BAMO)的分子构架上有两个N_3键。聚BAMO是一种典型的高能叠氮聚合物。因为聚BAMO在室温下为固体,为了制得固体推进剂的高能粘合剂,合成了BAMO和四氢呋喃(THF)的液态共聚物。进行了各种实验,以便阐明BAMO的聚合物、BAMO/THF共聚物以及交链的BAMO/THF共聚物的分解和燃烧过程。它们分解产生的热量是因N_3键断裂生成N_2气造成的。交链的BAMO/THF共聚物的燃速特性主要取决于BAMO和THF的摩尔比。     

3-叠氮甲基-3-乙基氧杂环丁烷及其均聚物的合成与性能

为开发新型含能黏合剂,以三羟甲基丙烷、碳酸二乙酯、对甲苯磺酰氯、叠氮化钠为原料,合成出一种新型叠氮类氧杂环单体3-叠氮甲基-3-乙基氧杂环丁烷（AMEO）。用核磁、红外、元素分析和DSC表征了AMEO的结构与性能。以1,4-丁二醇为起始剂,三氟化硼乙醚络合物为催化剂,二氯甲烷为溶剂,AMMO为单体,借助于阳离子开环聚合,合成出聚3-叠氮甲基-3-乙基氧杂环丁烷（PAMEO）。用红外光谱、核磁共振、元素分析、羟值、数均分子质量表征和测定了聚合物的结构和性能。     

BAMO基聚合物的合成及应用研究进展

简要介绍了3,3–双(叠氮甲基)氧杂环丁烷(BAMO)单体的性质及合成,从聚合方式、机理、不同软段及改性应用等方面着重介绍了叠氮类含能黏合剂BAMO均聚物和共聚物的合成及应用,并对其未来研究方向进行了展望。     

原位聚合包覆HMX的研究

为探索制备PBX的新方法,利用原位聚合反应,直接在HMX表面包覆一层热塑性高聚物,获得了分别以端羟基聚丁二烯(HTPB),聚叠氮缩水甘油醚(GAP)、3,3-双(叠氮甲基)环氧丁烷-四氢呋喃共聚醚(BAMO-THF)3种黏结剂包覆的PBX.通过光学显微镜、显微-红外、光电子能谱(XPS)、元素分析和机械感度测定对包覆效果进行表征.结果表明,HMX表面较均匀地包覆上了一层聚合物,黏结剂的质量分数约为4%～5%,包覆HTPB的HMX机械感度明显下降,而包覆GAP和BAMO-THF的HMX机械感度略有降低.     

新型含能粘结剂AMMO及其应用研究

综述了近几年来国外新型含能粘结剂AMMO（叠氮甲基－3－甲基氧杂环丁烷）的一些性能及AMMO／AP推进剂和AMMO／HMX推进剂的热分解和燃烧特性。     

叠氮类热塑性弹性体对模压可燃药筒燃烧性能的影响

为降低模压可燃药筒的初始燃烧速度,采用叠氮类热塑性弹性体BAMO/AMMO和BAMO/GAP分别对模压可燃药筒进行表面涂覆处理,并通过密闭爆发器试验及抗拉强度试验,研究了两种叠氮热塑性弹性体对可燃药筒定容燃烧性能和力学性能的影响。结果表明,经BAMO/AMMO和BAMO/GAP处理后的药筒在高温(50±2)℃、常温(25±2)℃及低温(-40±2)℃下密闭燃烧结束时间明显延长,燃烧初始速度和最大压力梯度下降;燃烧残渣质量相当,火药力和常温力学强度略微下降;常温下,BAMO/AMMO和BAMO/GAP涂覆的药筒燃烧结束时间较未处理药筒分别延长134%和22%,最大压力梯度分别降低52.3%和5.1%,表明用BAMO/AMMO和BAMO/GAP对可燃药筒进行表面处理,可有效降低药筒的初始燃气生成速率;常温下,BAMO/AMMO处理药筒和BAMO/GAP处理药筒的抗拉强度分别为25.82和26.46MPa,与未处理药筒相比力学性能略微下降。     

Use of molecular dynamics to investigate polymer melt-metal wall interactions

The classical boundary condition of fluid dynamics, i.e. the no-slip condition is violated during the flow of various complex fluids including polymer melts and polymeric suspensions. It is recognized that the dynamics of the behavior of the macromolecules at the wall, their adsorption, and disentanglement from each other and from the wall all play significant roles during shearing and flow. During wall slip it is not clear whether the macromolecules detach from the wall (adhesive failure of the slip condition) or whether the macromolecules remain tethered to the wall but disentangle from the neighboring macromolecules (cohesive failure). In this study, we seek to shed light to the basic mechanisms of the wall slip of polymers by focusing on the dynamics of the polymer behavior at the wall for three polymers, two of which exhibit significant strong wall slip, high density polyethylene (HDPE) and poly(dimethylsiloxane) (PDMS), and one which does not exhibit wall slip under typical extrusion conditions, i.e. a block copolymer BAMO/AMMO, (crystalline blocks of poly(3,3-bis(azidomethyl)-oxetane), BAMO, and amorphous blocks of poly(3-azidomethyl)-3-methyl-oxetane, AMMO). The cohesive energy densities of the three polymers were found to be in the same range, with the cohesive energy density of BAMO/AMMO being slightly higher than those of the other two. The molecular dynamics based cohesive energy density values compared well with calculations based on the determination of the group molar attraction constants. On the other hand, the energy of adhesion value exhibited by the copolymer BAMO/AMMO/iron oxide is significantly higher than the energy of adhesion values for the iron oxide/PDMS and iron oxide/HDPE systems. Considering that over the same broad range of shear stresses the block copolymer BAMO/AMMO does not exhibit wall slip and the other two polymers HDPE and PDMS do, these findings suggest that at least for these three polymers wall slip is more likely to occur on the basis of an adhesive failure mechanism.     

Thermal Decomposition of BAMO Copolymers

The effects of copolymerization of THF, as an inert component, AMMO, as an energetic one and NMMO, as a nitrate ester, with BAMO on their thermal decomposition are reported here. Although the thermal decomposition of the BAMO and NMMO units in B/N(7/3) carry out independently and the heat generated by the NMMO unit decomposition accelerates the BAMO unit decomposition, the THF and AMMO units do not affect that of the BAMO unit in B/T(7/3) and B/A(7/3). One exothermic peak in DSC is shown for B/A(7/3) and B/T(7/3) except for B/N(7/3) which shows two peaks. One peak at lower temperature is from the NMMO unit decomposition and the other is from the BAMO unit. The rate of decomposition of B/A(7/3) is the same as that of poly(BAMO), which indicates that the reactivity of the AMMO unit is equal to that of the BAMO unit. In propellant, containing 75% HMX and 25% copolymer binder, burning rate of B/A(7/3)/HMX is faster than that of B/N(7/3)/HMX. Although the heat of decomposition for B/A(7/3) in DSC is smaller than that for B/N(7/3), that of B/A(7/3)/HMX is larger than that of B/N(7/3)/HMX. The reaction occurred in the condensed phase of the propellant, therefore, may play an important role in the combustion.     

Characterization of P(BAMO/AMMO) ETPE Prepared Using Different Diisocyanates

Poly(3,3‐bisazidomethyl oxetane/3‐azidomethyl‐3‐methyl oxetane) energetic thermoplastic elastomers (P(BAMO/AMMO) ETPEs) is one of the most valuable ETPEs in the field of energetic binders. P(BAMO/AMMO) ETPEs were prepared using different diisocyanates (TDI, HMDI, IPDI, and HDI) to investigate the influence of the diisocyanate on the performance of P(BAMO/AMMO) ETPEs. Mechanical properties and heats of formation were investigated. FT‐IR spectroscopy results showed that TDI‐based ETPE has the highest degree of hydrogen bonding with a value of 69.00 %. Mechanical test results showed that the TDI‐based ETPE has better mechanical property with maximum stress at 5.24 MPa and breaking elongation at 390 %. The order for degree of hydrogen bonding and mechanical property of different diisocyanate‐based ETPEs was TDI>HMDI>IPDI>HDI. The heats of formation were calculated by the group additivity method and by the heat of combustion method. The values of heats of formation for TDI‐based ETPE were 3.44 kJ g⁻¹ and 3.75 kJ g⁻¹ according to the two methods. Additionally, TDI‐based ETPE has a lager heat of formation than the other ETPEs.     

Structure of Urethane Copolymers of 3,3‐Bis(azidomethyl)oxetane and 3‐Azidomethyl‐3‐methyloxetane

Polyurethane copolymers of 3,3‐bis (azidomethyl) oxetane (BAMO) and 3‐azidomethyl‐3‐methyloxetane (AMMO) with molecular structures of types B(AB)n, A(AB)n, (BB)n and ABn with different ratios of oligomeric units were investigated, where A is the non‐crystallizable “soft” block of oligoAMMO and B is the “hard” block of oligoBAMO and the included urethane diol fragments. The amorphous‐crystalline structures of copolymers BAMO and AMMO were elucidated by wide angle X‐ray diffraction measurements. The influences of the molecular structure and the ratio of oligomeric units on the structural parameters were identified. The degree of crystallinity is in a range from 8 to 22 % and sizes of the crystallites were determined. The defectivenesses of first and second kind in the structure were evaluated, which show high values of the first kind defectiveness (approx. 20 %), which describes the displacement of theoretical lattice sites and the existence of unequal sizes of the lattice sites, and minor values for the second kind defectiveness (approx. 3 %), which describes the lattice site disorder in large distances. Small‐angle X‐ray diffraction measurements were used to investigate the domain structures of copolymers BAMO and AMMO. The distribution and sizes of the crystallites in the structures of the copolymers were calculated.     

Probing the compatibility and interaction of energetic binders based on 3,3‐bis(azidomethyl)oxetane with some explosives: thermal,interfacial and simulation studies

Several polymer binders based on 3,3‐bis(azidomethyl)oxetane (BAMO) were studied to explore the compatibility and interaction of the energetic binders with three common energetic oxidants. The compatibilities were studied by differential scanning calorimetry and ratings were obtained according to evaluated standards. The results showed that all the binders based on BAMO had good compatibility with cyclotrimethylenetrinitramine, cyclotetramethylenetetranitroamine and hexanitrohexazaiso‐wurtzitane. The work of adhesion (W_a) between binders and explosives was tested via measurement of contact angle and the results are in the following order: chain‐extended poly(3,3‐bis(azidomethyl)oxetane) (PBAMO) by isophorone diisocyanate (IPDI‐CE) with diethyl bis(hydroxymethyl) malonate (IPDI‐DBM‐CE) > chain‐extended PBAMO by IPDI‐CE > PBAMO. In addition, similar results were found in the binding energies reported by molecular dynamics, and the average values of E_binding for the IPDI‐DBM‐CE system were larger than E_binding for the other systems due to the formation of hydrogen bonds between –COOEt and –NO₂, which improve the bonding abilities. © 2017 Society of Chemical Industry     

Energetics of BAMO

3,3-Bis(azidomethyl)oxetane (BAMO) is a typical energetic azide polymer containing two N₃, bonds in the molecular structure. Since BAMO is a solidified polymer at room temperature, a liquid BAMO copolymer with tetrahydrofuran (THF) was synthesized in order to gain energetic binders for solid propellants. Various types of experiments were carried out to elucidate the decomposition and combustion processes of BAMO polymer, BAMO/THF copolymer, and crosslinked BAMO/THF copolymer. The heat produced by the decomposition is caused by the bond breakage of -N₃ to produce N₂, gas. The burning rate characteristics of crosslinked BAMO/THF copolymer depend largely on the mole fraction ratio of BAMO and THF.     

Rheological studies on energetic thermoplastic elastomers

Energetic thermoplastic elastomers containing energetic groups, such as azido, nitrato, nitro, and so forth, are emerging as attractive binder systems for advanced solid rocket propellants. Poly[3,3‐bis(Azidomethyl) oxetane (BAMO)‐co‐3‐azidomethyl‐3‐methyl oxetane (AMMO)] comprising hard crystalline BAMO segment and the soft/amorphous AMMO segment in various molar ratios (80 : 20, 50 : 50 and 20 : 80) were synthesized during the present work. The homo polymers namely Poly‐BAMO and Poly‐AMMO were also synthesized. All the polymers and copolymers were characterized by spectral and thermal methods. They were found to be thermally stable. The most promising 80 : 20 copolymer softened at 56°C with T_g of −36°C. Rheological studies were also carried out to determine their suitability as a binder in explosive and propellant formulations. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal characteristics of energetic polymers based on tetrahydrofuran and oxetane derivatives

Thermal characteristics and decomposition behaviors of energetic polymers based on oxetane derivatives, 3,3'-bis(azidomethyl)oxetane (BAMO), 3-azidomethyl-3'-methyloxetane (AMMO), 3-nitratomethyl-3'-methyloxetane (NMMO), and 3,3'-bis(ethoxymethyl)oxetane (BEMO), were studied by means of differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA). These polymers were found to exhibit low glass transition and large decomposition onthalpies which were brought about by the attached azide (? N₃) and nitrato (? ONO₂) groups. The decomposition enthalpies depended on the types and contents of the energetic substituents. The NMMO-based polymers exhibited relatively higher decomposition enthalpies and less thermal stability than the others. Furthermore, the thermal stability of the polymers was further improved by partial curing treatment. These results reveal that these polymers are potentially useful for application in energetic propellant binders. © 1995 John Wiley & Sons, Inc.