全海深浮力材料性能分析

由环氧树脂、甲基四氢苯酐和KH550处理的空心玻璃微珠制得浮力材料,采用全海深环境模拟装置,参考美国军用标准MIL-S-24154A,研究了110 MPa全方位静水压下浮力材料的密度对其吸水性的影响,并对静水压测试前后浮力材料的力学性能作了测试。结果表明,随着浮力材料密度的降低,其吸水率升高。测试前后材料的压缩强度和弹性模量未发生明显变化。同一静水压下,表面喷涂聚脲弹性体的浮力材料吸水率更低。极限破坏压力试验表明,142 MPa的静水压下浮力材料完整无破损,能够满足全海深环境的应用要求。     

6000米用高强度低密度固体浮力材料的制备及性能研究

选用双酚A型环氧树脂和酸酐固化剂,采用真空法制备了低密度、高强度的空心玻璃微珠/环氧树脂固体浮力材料。通过密度测试、耐全方位静水压测试和压缩性能测试等手段对浮力材料进行了表征。结果表明,制备的浮力材料密度为(0. 58±0. 02) g/cm3,66MPa、24h全方位静水压下的吸水率小于0. 4%,平均压缩强度大于69. 93MPa,完全达到使用要求。     

深海环境下浮力材料的力学性能研究

浮力材料凭借其优异的机械性能和低密度,在深海装备、航空航天及生活用品中的应用越来越广泛。将空心玻璃微珠填充环氧树脂基体中采用模压的方法制备了三种密度浮力材料,对产品全方位静水压(12.5MPa)作用后的力学性能、尺寸稳定性、吸水率等进行了测试。结果表明,浮力材料经过全方位静水压作用后,压缩性能基本没有变化,剪切强度保留率在95%以上,拉伸强度和冲击强度都有所提高,尺寸稳定性好,吸水率随着静水压作用时间的延长先快速升高后趋于稳定。     

国内空心玻璃微珠/环氧树脂基固体浮力材料研究进展

从提高压缩强度、降低吸水率、降低密度三个方面对国内空心玻璃微珠/环氧树脂基固体浮力材料的研究进展进行综述,并对空心玻璃微珠/环氧树脂基固体浮力材料的未来发展方向进行了展望。     

碳纳米管增强固体浮力材料性能研究

采用超声分散和模具浇注成型法制备环氧树脂/多壁碳纳米管/空心玻璃微珠固体浮力材料。研究了碳纳米管用量对固体浮力材料密度、压缩性能及吸水性的影响。结果表明:当空心玻璃微珠体积分数为60%时,随着碳纳米管用量的增加,复合材料的压缩强度先提高后降低;当碳纳米管用量为0.1%时,复合材料的压缩强度最高(44.03 MPa),密度为0.572 g/cm3,吸水率低于1.0%;随着碳纳米管用量的增加,固体浮力材料的压缩强度和密度降低,吸水率提高。     

深海浮力材料的研制

以环氧树脂为基体,选用低分子聚酰胺树脂为固化剂,液体聚硫橡胶为增韧剂,并填充经表面活化处理的空心玻璃微珠,制得高强度、低密度、低吸水率的深海浮力材料。结果表明,随着空心玻璃微珠用量的增加,深海浮力材料的密度、压缩强度和冲击强度均逐渐降低,而吸水率上升。当固化剂TY–203的质量分数为环氧树脂的1/2、增韧剂液体聚硫橡胶的质量分数为10%、改性空心玻璃微珠的质量分数为35%时,制得深海浮力材料的综合性能较好,密度为0.633 g/cm3、压缩强度为45.21 MPa、冲击强度为36.39 J/m、吸水率为0.67%。     

聚氨酯弹性体在固体浮力材料上的应用

固体浮力材料是一种低密度、高强度多孔结构材料。将聚氨酯弹性体喷涂在材料表面作为阻水层使用,能有效降低材料吸水率和体积变形率,对提高固体浮力材料水下使用安全性和可靠性具有重要意义。     

颗粒复合肥料水田施用中克服漂浮问题的技术研究

分析复合肥颗粒施用于水田时漂浮的原因,确定漂浮物成分。为克服复合肥漂浮问题,甄选出表面活性剂F-20,探究F-20对复合肥颗粒漂浮、防结块效果、强度的影响,结果证明在油性防结剂中添加F-20后,肥料抗漂浮性好,对防结块效果、颗粒强度无明显影响。对设备进行改造,将F-20应用于实际生产过程中后节约了生产成本,提高了产品质量,彻底解决了复合肥颗粒漂浮问题。     

组装式铝合金内浮顶结构的设计分析

内浮顶是漂浮在油罐液面上随油品上下升降的浮动顶盖。采用这种内浮顶盖覆盖在液面上是目前公认的最理想的降低油品蒸发损耗的方法。由于内浮顶在工作过程中要始终保持漂浮于液面上的状态,因此在设计时一定要保证其有足够的浮力,同时要保证各个部位的连接强度及稳定性。就内浮顶进行了强度、稳定性、浮力等相关方面的计算。     

长输管道常用浮力控制技术的比较分析及应用

水下穿越管段在没有达到安全埋深甚至裸露时，受到水流的浮力与动力的作用，可能引起管段的漂浮或移位，危及管道的安全。因此必须对水下穿越管道进行稳定。本文对传统的浮力控制技术以及国内外的一些浮力控制新技术进行了简单的介绍，并针对甬台温天然气输气管道工程的实际情况，对不同的水流、地质情况给出了推荐的稳管方式。     

Enhanced gastric retention and drug release via development of novel floating microspheres based on Eudragit E100 and polycaprolactone: synthesis and in vitro evaluation

Eudragit E 100 and polycaprolactone (PCL) floating microspheres for enhanced gastric retention and drug release were successfully prepared by oil in water solvent evaporation method. Metronidazole benzoate, an anti-protozoal drug, was used as a model drug. Polyvinyl alcohol was used as an emulsifier. The prepared microspheres were observed for % recovery, % degree of hydration, % water uptake, % drug loading, % buoyancy and % drug release. The physico-chemical properties of the microspheres were studied by calculating encapsulation efficiency of microspheres and drug release kinetics. Drug release characteristics of microspheres were studied in simulated gastric fluid and simulated intestinal fluid i.e., at pH 1.2 and 7.4 respectively. Fourier transform infrared spectroscopy was used to reveal the chemical interaction between drug and polymers. Scanning electron microscopy was conducted to study the morphology of the synthesized microspheres.     

Preparation,characterization and preliminary calcium release study of floating sodium alginate/dextran‐based hydrogel beads: part I

Ionically crosslinked calcium alginate/dextran‐based floating beads were prepared using NaHCO₃ as porogen. Various micrometric properties such as tapped density, apparent density, compressibility index, etc., were determined for beads with different compositions. The beads were also evaluated for their mechanical strength. The percent buoyancy of the beads was measured as a function of time in simulated gastric fluid (pH = 1.2 at 37 °C). The beads prepared with higher concentrations of NaHCO₃ porogen and CaCl₂ crosslinker possessed 100% buoyancy and remained buoyant for nearly 20 h, or even more. Finally, the release of calcium from the beads was observed to follow diffusion‐controlled Higuchi kinetics. Copyright © 2007 Society of Chemical Industry     

初始浮力比对多组分液体分层失稳的影响

采用实验研究手段,在可视化矩形容器内构造多组分液体分层系统,通过分析不同质量分数差和侧壁漏热下容器内流体的分层演化规律和温度响应情况,揭示初始浮力比（R_ρ）对系统失稳形态、分界面移动速度、失稳积聚能量和分层系统稳定性的影响。结果表明随着初始浮力比的增大,分层结构失稳形态和分界面移动速度呈现不同规律,且存在临界初始浮力比（R_ρc）使分层系统保持稳定。当初始浮力比较低时（R_ρ≤0.35）,边界浮升流穿透分界面后可到达液体表面,掺混区域位于上层液体上部,分界面下移速度整体较快,后期逐渐减慢;当初始浮力比较高时（0.47≤R_ρ≤R_ρc）,边界浮升流不能到达液体表面,掺混区域主要位于上层液体侧部,分界面下移速度整体较慢,后期逐渐加快。同时发现,随着初始浮力比的增加,分界面穿透时间延后,分层失稳时积累能量越多,这导致漏热率相同时,初始质量分数差较大的情况更加危险;而质量分数差相同时,可能存在漏热率低而更危险的情况。     

淀粉基聚乙烯醇完全生物降解塑料薄膜的结构与性能

通过优化工艺条件，制备了高淀粉填充量的淀粉／聚乙烯醇完全生物降解塑料薄膜，研究了提高淀粉用量对淀粉／聚乙烯醇（PVA）完全生物降解塑料薄膜的力学性能和耐水性影响；并分析了耐水改性助剂尿素用量对薄膜的吸水率和生物降解性能的影响。结果表明，通过先糊化、后共混、再交联的薄膜制备工艺过程，能够获得高淀粉填充量的淀粉／聚乙烯醇完全生物降解塑料薄膜；先糊化打破了淀粉颗粒的原有形态结构，促进了淀粉与聚乙烯醇的共混相容性，从而获得了优良的力学性能；耐水改性助剂尿素的使用，能够大幅度地降低材料的吸水率，同时提高材料的生物降解性和环境友好程度。     

深海环境下环氧树脂吸水机理研究

利用环氧树脂TDE-85分别与固化剂651、T403固化制备了树脂基体样片,采用深海模拟设备进行高静水压吸水性能研究,并通过傅里叶红外(FT-IR)和扫描电镜(SEM)考察了环氧树脂高静水压处理前后结构变化。研究结果表明,高静水压环境下,环氧树脂的吸水过程分为3个阶段,即快速吸水阶段、缓慢吸水阶段和吸水平衡阶段;环氧树脂自由体积和极性基团浓度决定着高静水压力对水分子的进入起促进还是抑制作用;水分子的大量进入会导致树脂基体发生水解等不可逆破坏。     

Properties of heat resistant hollow glass microsphere/phosphate buoyancy materials with different coatings

The heat resistant buoyancy materials were fabricated by the molding method using the aluminum dihydric phosphate as the matrix and hollow glass microspheres as the filler, respectively. In order to improve the waterproof performance of the buoyancy, two strategies, adding the B₄C additives and introducing the silica-based coatings, were adopted. The study showed that the samples with the B₄C content of 10 wt% possessed the optimal comprehensive performance, such as low density (0.540 g/cm³) and low water absorption (29.6%). The effect of the coating types and coating times on the density, water absorption, compressive strength and specific strength of the buoyancy materials were also studied. After 4 times of coating, the density and the compressive strength of the sample increased to 0.62 g/cm³ and 6.0 MPa, respectively; the water absorption of the samples greatly decreased to 10%. Besides, all samples exhibited significant pseudoductility. The buoyancy materials with the above superior properties can be potentially used in the deep see fields.     

Wood-inspired polyacrylonitrile foam with hierarchically aligned porous structure for application in water purification

The main purpose of this study is to verify the excellent absorption efficiency of polyacrylonitrile (PAN) foam which has a hierarchically aligned porous structure similar to wood for water purification. Ice template and freeze drying method was employed to prepare the PAN foam, and the performance of the prepared sample was characterized by advanced technology. Experimental data revealed that the micromorphology, absorption efficiency, and mechanical properties were tunable by controlling the polymer concentration in solution. The PAN foam prepared at 7 wt% not only had excellent absorption efficiency, but also had great water flux. The highest absorption efficiency of the PAN foam prepared at 7 wt% for the model dye, methylene blue, reached 97.83%. Therefore, a new strategy for water purification by filtration using a scaffold with a hierarchically aligned porous structure is possible.     

高强度浮力材料的研制

以高强度液态不饱和聚酯树脂(UPR)为基体,经表面活化处理的空心玻璃微珠为填充剂,经混合、浇注、固化,制得高强度深海浮力材料。介绍了降低浮力材料密度的途径,研究了浮力材料密度与抗静水外压、浮力材料密度与空心微珠填充量的关系以及浮力材料结构对性能的影响。结果表明:空心微珠的填充量越高,浮力材料的密度越低,同时也会降低浮力材料的抗静水外压强度;采用同种空心微珠制备的浮力材料,其密度越高,抗静水外压强度越好;通过对空心微珠的表面活化处理,可以提高浮力材料的抗静水外压强度。