【作者】 菅晓霞；

【导师】 徐复铭； 周伟良；

【作者基本信息】 南京理工大学 ， 材料科学与工程， 2009， 博士

【摘要】 由弹性体、硝酸酯和高能填充物为主要成分的高能量、高强度发射药是目前发射药发展的重要方向,作为主要组份的弹性体粘结剂是其重要研究内容之一。本文借鉴NEPE (nitrate ester plasticized polyether)推进剂中应用的硝酸酯可增塑聚乙二醇(PEG)类弹性体设计、合成方法,针对发射药的强度要求和加工特点,结合互穿／半互穿网络聚合物技术,在我国首先开展了发射药用硝酸酯可增塑热塑性弹性体的设计、合成工艺及其力学性能研究,获得了未见文献报道的物理缠结型P(MMA/EA)/PEG-TPE互穿网络聚合物,为发展高能量、高强度发射药提供粘结剂方面的理论和应用基础,探索研究了GAP基含能热塑性弹性体的合成与性能。主要开展了以下几方面工作：为提高以弹性体为粘结剂的发射药强度,通过对热塑性弹性体(TPE)结构分析和分子设计,采用不同于NEPE推进剂的高分子量PEG类预聚体,选择了相对分子质量较低的PEG为软段,MDI和EDO为硬段,合成了一类PEG-TPE。用DSC、FTIR和DMA等分析手段对弹性体的结构和性能进行了表征,合成的样品具有氨基甲酸酯基的特征结构和一定的微相分离,软段玻璃化转变温度低,硬段含量为50%,R=1的弹性体拉伸强度(6b)为3.75MPa,断裂伸长率(εb)为469%，扫描电镜照片表明合成的PEG-TPE具有较均一的断面形貌。为提高PEG-TPE的拉伸强度,通过顺序互穿引入聚甲基丙烯酸甲酯(PMMA)合成了PMMA/PEG-TPE热塑性弹性体,PMMA的引入使6b由PEG-TPE的3.75MPa提高到PMMA/PEG-TPE (60/40,质量比,下同)的24.2MPa,ε_b由PEG-TPE的469%降为PMMA/PEG-TPE的4.6%,是一类强而脆的弹性体粘结剂；DMA分析显示PMMA/PEG-TPE具有两个玻璃化转变温度(Tg)，低温区的Tg对应于PEG-TPE软段的玻璃化转变,高温区的Tg对应于PMMA的玻璃化转变。为提高PMMA和PEG-TPE聚合物网络间的互穿水平,以EGDMA为PMMA的交联剂,合成了交联PMMA/PEG-TPE半互穿网络聚合物。DMA分析显示质量比为10/90的交联PMMA/PEG-TPE只有一个玻璃化转变温度,质量比为30/70和50/50样品的两个玻璃化转变峰与PMMA/PEG-TPE相比都向中间靠拢,表明互穿程度得到提高；质量比为20/80时,σb和εb分别由PMMA/PEG-TPE的6.32MPa、450%提高到交联PMMA/PEG-TPE的12.7MPa和951%,拉伸强度和韧性得到了优化。由于交联PMMA/PEG-TPE难以满足发射药挤出成型的加工要求,为此设计并合成了以兼具刚性PMMA链段和柔性PEA链段的P(MMA/EA)为客体,PEG-TPE为主体的P(MMA/EA)/PEG-TPE互穿网络聚合物。DMA分析表明,质量比为10/90和30/70的P(MMA/EA)/PEG-TPE具有单一的玻璃化转变峰；P(MMA/EA)/PEG-TPE (10/90)的σb和ε_b分别为14MPa和412%,属于强而韧的弹性体粘结剂,力学性能具有正协同效应；在所测溶剂中,PEG-TPE和P(MMA/EA)都可溶,而P(MMA/EA)/PEG-TPE只能溶胀；断面形貌照片显示样品的相区尺寸缩小且形貌较柔顺；由以上分析认为P(MMA/EA)/PEG-TPE体系属于物理缠结、互锁形成的互穿网络聚合物,并对形成物理缠结的结构模型进行了探析。该互穿网络聚合物未见文献报道。为满足发射药对更高能量的需求,采用预聚法,以聚叠氮缩水甘油醚(GAP)、MDI及1,4-丁二醇(BDO)为主要原料,合成了含能热塑性弹性体(GAP-ETPE)。考察了R值,硬段含量,以及增塑前后的弹性体的力学性能、动态力学性能和热性能。当R值为0.98,硬段质量百分含量为40%时,GAP-ETPE的σ_b为6.12MPa,ε_b为71%,以10%(质量比)BDNPF/A增塑后,GAP-ETPE的σ_b变为4.92MPa,ε_b为35%。为考察PEG类弹性体作为发射药包覆材料的迁移特性,初步探索研究了水、乙醇和DBP等组份在合成的PEG-TPE和P(MMA/EA)/PEG-TPE中迁移的渗透汽化表征方法,并与HTPB进行了对比分析。更多还原

【Abstract】 High energy, high strength gun propellant with elastomer, nitrate ester and high energetic oxidizer is the important aspect in the field of gun propellant, and the elastomer binder as the main component is the crucial research part. In this paper, upon the understanding of nitrate ester plasticized PEG(polyethylene glycol) elastomer in NEPE propellant, nitrate ester plasticized thermoplastic elastomer (PEG-TPE) for gun propellant binder are synthesized according to the strength and processing demand of gun propellant, and the properties of PEG-TPEs are studied. A novel type of interpenetrating network polymer, that is P(MMA-EA)/PEG-TPE, is synthesized. GAP based energetic thermoplastic elastomer is also synthesized. The main work as follows:For improving the strength of gun propellant with elastomer binder, a thermoplastic polyurethane elastomer is synthesized by lower molecular weight PEG as soft segment, which is different from higher molecular weight PEG in rocket propellant,4,4’-diphenylmethane diisocyanate (MDI) and ethylene glycol as hard segments. DSC, FTIR and DMA are applied to characterize the synthesized elastomers, the results show that the elastomers have structure characteristic of polyurethane structure, the elastomer tensile stress(σ_b) is 3.75MPa, elongation at break(ε_b) is 469% when hard segment is 50% in weight and the molar ratio of-NCO to-OH (R) is 1, the microstructure is homogeneous in SEM photographs.PMMA/PEG-TPE thermoplastic elastomer is synthesized by sequence interpenetrating technique to enhance the tensile stress of PEG-TPE. Theσ_b andε_b of PMMA/PEG-TPE(60/40, mass ratio, same as follows) are 24.2MPa and 4.6% whereas theσ_b andε_b of PEG-TPE 3.75MPa and 469%, showing that PMMA/PEG-TPE is a type of strong but brittle binder. The DMA analysis showed that PMMA/PEG-TPE have two individual glass-transition temperature (Tg), the lower Tg and the higher Tg are corresponding to those of PEG-TPE’s soft segment and PMMA’s respectively.The semi-interpenetrating polymer network of crosslinked-PMMA/PEG-TPE is synthesized using EGDMA as the crosslinking agent of PMMA, in order to improving the interpenetrating degree of PMMA and PEG-TPE polymer networks. The DMA testing shows that the crosslinked-PMMA/PEG-TPE (10/90) owns only one glass transition temperature, two glass transition temperatures of crosslinked-PMMA/PEG-TPE (30/70,50/50) shift towards to the center zone, implying the enhancement of the chains interpenetration. The ab and eb of crosslinked-PMMA/PEG-TPE(20/80) are 12.7MPa and 951%, while theσ_b andε_b of PMMA/PEEG-TPE are 6.32MPa and 450%, showing the optimization of tensile stress and toughness for crosslinked-PMMA/PEG-TPE.P(MMA/EA)/PEG-TPE interpenetrating polymer networks were synthesized by PEG-TPE and copolymer P(MMA/EA) of methyl methylacrylate and ethyl acrylate, considering that the crosslinked-PMMA/PEG-TPE is not suitable to the extrusion of gun propellant. The DMA testing shows that the P(MMA/EA)/PEG-TPE (10/90,30/70) have only one glass transition temperature. Theσ_b andε_b of P(MMA/EA)/PEG-TPE(10/90) are 14MPa and 412%, being a type of strong and tough binder and having the positive synergistic effect of mechanical properties. PEG-TPE and P(MMA/EA) can be dissolved for tested solvents, while P(MMA/EA)/PEG-TPE could only be swollen in tested solvents. The phase size contracts and the morphology is flexible from SEM photos. Thus, P(MMA/EA)/PEG-TPE is considered as a type of interpenetrating polymer networks with physical entanglement.An energetic thermoplastic elastomer (GAP-ETPE) was synthesized by melt-prepolymerization, using glycidyl azide prepolymer (GAP) as soft segments, MDI and 1,4-butanediol as hard segments for the purpose of higher energy gun propellants. The molar ratio of -NCO to -OH, hard segment content and mechanical properties, and dynamic mechanical properties are studied. Theσ_b andε_b of GAP-ETPE are 6.12MPa and 71%, when hard segment is 40% in weight and the R is 0.98. After the GAP-ETPE are plasticized by BDNPE/A, itsσ_b andε_b are 4.92MPa and 35%, respectively.A preliminary study is carried out that the pervaporation method is used to evaluate the migration properties of water, ethanol and DBP through PEG-TPE and P(MMA/EA)/PEG-TPE elastomer, in the case of PEG-TPE and P(MMA/EA)/PEG-TPE using as gun propellant coating materials.更多还原