Synthesis,morphology, component distribution,and mechanical properties of nitrocellulose/gradient poly(ethylene glycol dimethacrylate) semi‐IPN material

Nitrocellulose (NC), a rigid natural polymer, was modified by gradient interpenetrating polymer networks containing poly(ethylene glycol dimethacrylate) (PEGDMA) to obtain both high strength and large toughness across the thickness from surface to the core of samples. PEGDMA content decreased with distance from the surface to core of nitrocellulose with a gradient of poly(ethylene glycol dimethacrylate) (NC/grad. PEGDMA) determined by elemental chemical analysis. The distribution of the guest component across the NC/grad. PEGDMA semi‐IPNs sample thickness was reciprocal function. SEM micrographs of NC/grad. PEGDMA semi‐IPNs revealed that, when the content of guest component was about 23%, the gradient system showed almost single phase morphology. At the same time, the tensile test results showed that NC/grad. PEGDMA featured both higher tensile strength and larger toughness. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

双级推料离心机在硝化纤维素生产中的应用

根据硝化纤维素的物料特性,对P系列双级推料离心机分别从安全性、母液的分段回收、转鼓结构和表面涂层及自动化控制等方面进行了创新设计,不仅满足其生产过程中的脱酸、脱水和驱酒的工艺要求,而且完全超越了WH型推料离心机的脱酸、脱水和三足式离心机的驱酒效果,彻底解决了分离因数低、洗涤后不能分段收集、自动化程度不高、劳动强度大等缺陷。该机型集具高效、节能、环保、安全及自动化程度高于一体,是一种实用型节能环保设备。     

硝化纤维乳液的制备方法及其研究进展

综述了近年来硝化纤维乳液的主要制备方法,包括外乳化法、转相乳化法、种子乳液聚合法、自乳化法、化学改性法及互穿聚合物网络聚合法;介绍了每种方法的要素、特点及其研究进展;认为外乳化法产品稳定性最差,转相乳化法可改进的余地较小,种子乳液聚合乳化法最复杂,而自乳化法前景最为看好;建议我国加大该产品的研究力度。     

Fabrication and mechanism study of the nitrocellulose aqueous dispersions by solvent displacement method

The traditional preparation methods of nitrocellulose emulsion have many problems, such as high emulsifier content, complex preparation processes, or the need for high energy-consuming emulsification equipment. To address these issues, in this paper, the emulsifier-free NC dispersion was successfully prepared by a simple, low-energy solvent displacement method for the first time and the formation and stabilization mechanism of NC nanoparticles was also thoroughly investigated. The formation mechanism of the NC particles based on the “nucleation and aggregation” and the stabilization mechanism of the NC aqueous dispersions based on the electrostatic repulsion of anions were proposed and supported by experimental results. At the same time, we achieved effective control of the solid content of the NC dispersion by vacuum concentration. The obtained NC dispersion had a large range of adjustable sizes (63.82–143.43 nm), uniform size distribution (PDI < 0.2), a wide range of tunable solid content (0.5%–16%), and good stability (zeta potential < −20 mV), which has potential application in adhesives and coatings as promising candidates for traditional NC organic coatings.     

水性硝化棉光亮剂的研制

通过探讨影响水性硝化棉光亮剂的光亮度和乳液稳定性的各种因素,合成了一种水性硝化棉光亮剂,其成膜光亮、柔软,具有较好的乳液稳定性。     

含纳米铝粉的纳米NC纤维的制备

为了克服纳米铝粉在推进剂使用过程中分散不均匀的问题,采用静电纺丝技术制备了材料表面光滑、直径均匀、且纳米铝粉分散均匀的纳米NC纤维.用扫描电镜研究了含水率、溶液浓度、电压和挤出速率对纤维形态和直径的影响,得到静电纺丝最佳工艺条件:含水率为10%～15%,NC纺丝液质量分数5%～10%,电压25～30kV,挤出速率0.5...     

DBP对发射药燃烧可燃气体产物影响的理论研究

采用最小自由能算法理论研究了邻苯二甲酸二丁酯(DBP)对单基发射药燃烧生成可燃气体产物的影响规律,并利用定容燃烧试验对理论研究结果进行了验证.结果表明,配方中DBP含量超过某一临界值时,发射药燃烧会有固态游离碳生成;可燃气体的生成量随着DBP含量的升高先逐渐增加,并在DBP含量临界值时(生成游离碳)达到最大值,然后逐渐...     

用偏光显微镜检测硝化棉的含氮量

建立了偏光显微镜测定硝化棉含氮量的新方法.采用色那蒙法测定了平均光程差.结果表明,当硝化棉含氮量为11.0%～13.8%时,光程差与含氮量线性相关,线性回归方程为ω＝-0.0466λ+12.388,线性相关系数R＝0.9993.用硝化棉标准物质对新方法检测结果进行了验证,回收率为99.7%～100.2%,变异系数为0....     

涂料用自乳化型硝化棉乳液的制备与性能研究

硝基涂料尽管具有诸多优势,但因其VOC较高面临被限制甚至禁止使用的境地,将硝基涂料的主要成膜物质硝化棉水性化是降低乃至消除VOC的有效手段。本研究通过在硝化棉分子中引入亲水基团的方法制备了自乳化型水性硝化棉乳液,通过正交试验及其极差分析、均匀试验及其回归分析得出了最佳合成条件,并利用红外光谱、TEM、粒径分析仪、Zeta电位仪等对产物进行了表征。结果表明:所得水性硝化棉分子保留了原硝化棉的主体结构,乳液具有良好的稳定性,乳液粒子分散性良好且粒径均匀,表干时间为20 m in左右。该乳液已在烟盒涂料等领域获得了应用,今后有望应用于水性硝基涂料。     

基于真空热脱水工艺的硝化棉自动高效脱驱水生产线

针对目前国内普遍采用的离心机酒精置换离心驱水工艺已不能满足某些后续生产工序要求的问题,设计一种采用真空热脱水工艺的硝化棉自动高效脱驱水生产线。介绍了生产线工艺原理、工艺流程及设备组成,重点分析了真空热脱驱水工艺装备的3项关键技术:驱水棉含水量一致性控制、硝化棉浆管道输送和生产线安全保证技术,并采取了一系列措施保证硝化棉驱水质量、全线生产连续性和安全性。实践结果表明:该生产线驱水效率较高,劳动强度和环境污染降低,具备较高的安全性、可靠性和先进性,目前已投入到生产运行中。