STUDY OF FLAME RETARDING FINISH OF POLYPROPYLENE / VISCOSE BLEND FABRICS

The combustion mechanisms of PP / Viscose blend fabrics are briefly discussed, and the factors affecting flame retarding(FR) effect are analyzed. Apart from this, the choice of processes of FR finish is also discussed in this paper. Other factors such as coating add-on, curing temperature and time are studied too. The results show that the factors above all have different extent of influence upon FR effect.     

阻燃剂对共混腈纶结构和性能影响的研究

本研究采用广角x射线衍射、扫描电子显微镜、氧指数测定和热分析等方法,对添加不同量含溴阻燃剂FR和协同剂Sb_2O_3的共混阻燃PAN纤维的结构和性能进行分析。研究表明,FR和Sb_2O_3的加入,降低了纤维高序区的规整性,但对结合单元的取向态结构和纤维的宏形态结构的影响较小;FR和Sb_2O_3协同,对AN纤维具有良好的阻燃性,不会使纤维的物理一机械性能明显劣化,但对纤维的热性能有不同程度的影响。     

Nomex蜂窝夹芯板冲击损伤试验研究

针对某型飞机上应用的Nomex蜂窝夹芯板,通过冲击损伤试验,研究了蜂窝夹芯板厚度对其抗冲击损伤能力的影响、试件损伤面积与冲击能量之间的关系以及穿透损伤对夹芯板轴压承载性能的影响。结果表明:20 mm与8 mm厚度板在分别承受40 J与25 J冲击能量时出现穿透损伤,厚板比薄板具有更高的抗冲击损伤能力;相同冲击能量时,20 mm厚板损伤面积比8 mm板的小;随冲击能量的增大,两种板的损伤面积逐渐增大;当冲击能量超过一定值时,8 mm板损伤面积增速明显加快;20 mm蜂窝夹芯板冲击后的剩余强度为完好件的56.7%,8 mm蜂窝夹芯板冲击后的剩余强度为完好件的67.5%。     

Study on the Structure and Properties of Polynosic Fiber Treated by Alkali

The regenerated cellulose fibers, made from wood pulp, have excellent physical properties like cotton fiber. Especially polynosic fibers can be mercerized by alkali, but conventional Viscose fiber can not be treated or mercerized by alkali. The paper studies on behavior of polynosic fibers treated by alkali, including physical properties, such as weight loss, tensile strength and elongation, and fiber structures properties. In this paper, on the basis of study on polynosic fibers treated by alkali, the conclusions were drawn as following. Firstly, polynosic fiber is good at alkali resistance. Secondly, the changes of fiber structure and physical properties begin declining at 5 wt% NaOH concentration and reverse changes take place at 10 wt%.     

冷却方式对过冷压制PEN单聚合物复合材料的影响

为研究冷却方式对聚萘二甲酸乙二醇酯(PEN)单聚合物复合材料(SPC)的影响,分别采用了随机冷却、骤冷和自然冷却的方式,过冷压制成型了PEN SPC样品;使用DSC热分析法确定了冷却速度对PEN基体的影响;使用万能试验机比较了PEN SPC样品的力学性能. 研究结果表明:随机冷却的方式得到的PEN SPC的拉伸强度最小,拉伸模量最高,是由冷却速度慢导致结晶引起的;骤冷的方式得到的拉伸模量最低,是由冷却速度过快导致无定形引起的;自然冷却方式得到的拉伸强度最高,是由于适中的冷却速度有利于基体渗透.      

Influences of poly (vinyl alcohol) molecular weight and carbon nanotubes on radiation crosslinking shape memory polymers

Polyvinyl alcohol (PVA) of two molecular weights was used to prepare shape memory polymers based on chemical-crosslinking by glutaraldehyde. The chemical-crosslinking was done in the presence of 2-carboxyethyl acrylate oligomers (CEA) and nano-filler [multi-wall carbon nanotubes (MWCNT) and functionalized carbon nanotubes (MWCNT-NH2)] followed by radiation-induced crosslinking. The analysis of the material revealed an increase in the gel fraction and a significant reduction in swelling of the nanocomposite material that was crosslinked with both glutaraldehyde and ionizing radiation. The radiation crosslinked nanocomposites demonstrated approximately a 90% gelation over a range of 50–300 kGy irradiation doses. The scanning electron microscopy (SEM) analysis showed a homogeneous distribution of nanocomposites in the composite matrix. The thermal properties of radiation crosslinked (PVA/CEA) and (PVA-CEA)-nano-fillers were investigated by a thermogravimetric analysis (TGA). The mechanical properties were examined via dynamic mechanical analysis (DMA) which showed significant variation because of the addition of nanocomposites. This radiation crosslinked materials show good shape memory behavior that may be useful in many applications based on the range of temperatures at which Tan δ appears.     

基于HAM模型的竹材热湿物理性质试验研究

为获得典型竹材的材性参数,明确竹木之间以及不同竹材之间的差异,选择整竹展平板、竹集成材、竹胶合板、竹重组材、竹刨花板、大片竹材定向刨花板等6种代表性产品,系统地进行基于建筑围护结构HAM模型的热湿物理性质测试.项目包括:测定基本物理性质的密度计算和真空饱和实验;测定湿储存性质的平衡吸放湿实验;测定湿传递性质的毛细吸水实验、蒸气渗透实验和干燥实验;测定热储存性质的热分析;测定热传递性质的导热系数测试和表面光热性质测试.测试结果初步形成竹材热湿物理性质的参数基础;与18种木材产品的对比表明,竹材湿储存和湿传递性质普遍小于木材,而同时表征热储存和热传递性质的蓄热系数大于木材;6种竹材之间的对比表明,竹材改性有利于均匀性的提高,可拓展其材性频谱范围,并使区别于木材的特性得到强化.     

Influence of parameters on the microstructure of a duplex stainless steel joint welded by a GMAW welding process

Duplex stainless steels (DSSs) are widely used in industry for their desirable properties. Any fusion welding technique modifies the microstructure and, consequently, the properties of the material. This paper presents a parametric study of the variables that determine the energy contribution (current, voltage and welding speed) and the structural modifications produced during gas metal arc welding. The analysis comprises metallographic study, phase balance, dimensioning of the weld beads and tensile and hardness tests. The influence of the variables studied on the thermal cycles obtained (temperatures reached and cooling rate) was determined by using a finite element model. The results showed that, in addition to the indicated parameters, the parameter power transfer per volume (W/m³) and the geometry in the bead must be controlled due to their influence on the heat flow distribution and phase balance.     

稀土配合物Eu(TTA)_3(TPPO)_2的合成、表征及发光性质研究

制备了Eu(TTA)3(TPPO)2二元及三元稀土配合物,通过热重差热分析、红外光谱、紫外光谱和元素分析对配合物的组成、结构进行了表征.研究了配合物溶解性、热稳定性和TPPO第2配体加入对配合物发光性的影响.荧光光谱的研究表明,第2配体的加入能有效地增强铕离子发光强度,配合物具有良好的发光性能,在紫外光激发下显示出Eu3+的特征发射峰,发出很强的红色荧光,是一种有潜在应用前景的红光发光材料.     

BCF的热氧稳定化研究

采用连续实验方法,借助X射线衍射、红外光谱、元素分析、力学测试等技术,系统地研究了热氧稳定化过程中聚丙烯腈纤维序态结构、化学结构与生物碳纤维吸附特性、力学性能的内在关联与作用.研究结果表明:聚丙烯腈基热氧稳定化纤维晶区尺寸、取向指数等结构参数与BCF比表面积、吸附特性及力学性能的优劣具有直接内在联系.在热氧稳定化过程中增加聚丙烯腈纤维热氧稳定化结构转化有益于改善生物碳纤维吸附特性,且与生物碳纤维力学性能的变化密切相关.     

P(MMA-CO-BA)热敏型微胶囊的制备及性能研究

采用乳液聚合法,以染料隐色体为芯材,交联聚(甲基丙烯酸甲酯-丙烯酸丁酯)(P(MMA-CO-BA))为壁材,通过调整BA在共聚单体中的质量分数制备了具有不同玻璃化温度的交联P(MMA-CO-BA)热敏型微胶囊.利用粒度分布仪、扫描电镜(SEM)、热重分析(TG)仪、差示扫描量热(DSC)仪表征了微胶囊的粒径分布、形貌、热稳定性和玻璃转化温度.结果表明:所得微胶囊具有良好的热稳定性;微胶囊粒子分布均匀,呈规则的球形;共聚单体中BA质量分数增加,微胶囊的平均粒径减小;BA在共聚单体中质量分数为5.0%,10.0%和15.0%时,所得微胶囊的玻璃化温度分别为115.0,110.3和94.3 ℃.     

流体平移式电卡制冷系统模拟及性能分析

为了改善电卡制冷的性能，以三元聚偏氟乙烯（PVDF）为电卡材料，构建了流体平移主动式电卡蓄冷器（AER），并基于COMSOL Multiphysics多物理场仿真平台建立了该AER系统的二维模型，进行性能仿真。通过特定工况及变参数分析，讨论了电卡制冷的影响因素，发现材料导热性能是制约电卡效应发挥的重要因素，导热性能不佳不但导致施加电场时材料热量无法有效传递给流体，而且会发生温度交叉，导致去电场时未有效降温的材料中心与流体抢夺电卡效应冷量的现象。     

Preparation and characterization of poly(vinylidene fluoride) composite membranes blended with nano-crystalline cellulose

Poly(vinylidene fluoride) (PVDF) composite membranes blended with nano-crystalline cellulose (NCC) for ultrafiltration were prepared by a Loeb-Sourirajan (L-S) phase inversion process.The effects of NC...     

耐高温高分子材料的热分解动力学

本文用热重法研究了四种耐高温分子材料:聚芳醚酮酮、热致性液晶共聚芳酯、溶致性液晶聚芳酰胺和聚间苯二甲酰间苯二胺的热分解动力学.采用Ozawa方法和Coata-Redforn方法处理并计算了热分解动力学参数:活化能Ed、反应级数n、频率因子A．     

玻璃纤维增强泡沫混凝土性能试验研究

在泡沫混凝土中加入不同掺量玻璃纤维,制成纤维泡沫混凝土复合材料,测定了它的物理力学性能.结果表明,加入玻璃纤维增加了泡沫混凝土的抗压强度和抗折强度,极大地改善了韧性,并在一定程度上抑制了早期干缩开裂,而且对导热系数影响不大;因此,加入玻璃纤维可以有效改善泡沫混凝土的性能.     

对甲苯磺酰氨基酸甲醇或2,2-联吡啶混配Cu(II)配合物的电化学合成及表征

采用金属Cu为“牺牲阳极”,在含配体对甲苯磺酰L-异亮氨基酸(H2L)的甲醇溶液中电解合成了[Cu(L)(2CH3OH)]配合物.当向含配体的甲醇溶液中加入2,2′-联吡啶时,电解合成了[Cu(L)(2,2’-bipy)]配合物.利用元素分析、红外光谱、紫外光谱、热分析对配合物进行了表征.测试了铜电极在溶液中的电化学行为和配合物的电化学性质.     

氢氧化铝/氢氧化镁/芳砜纶复合材料的制备及其性能

采用二次生长的方法,在芳砜纶(PSA)织物表面制得氢氧化镁(Mg(OH)2,MH)片状晶体;通过控制pH值并采用原位生长的方法,使氢氧化铝(Al(OH)3,ATH)凝胶包覆已生长了片状氢氧化镁晶体的芳砜纶织物(MH/PSA),从而成功制得氢氧化铝/氢氧化镁/芳砜纶(ATH/MH/PSA)复合阻燃材料.采用电感耦合等离子体发射光谱仪(ICP)分析MH/PSA及ATH/MH/PSA样品中Mg和Al含量,利用扫描电子显微镜(SEM)观察其表面形态,并对MH/PSA和ATH/MH/PSA的隔热性能及防紫外红外辐射性能进行测试及对比.研究结果表明:通过二次生长和原位生长的方法,将两种无机阻燃剂处理到织物表面是可行的,MH/PSA和ATH/MH/PSA复合材料的隔热性能和防紫外红外辐射性能都较原PSA织物有明显的提高,其中ATH/MH/PSA复合材料的性能更佳.     

Skin collagen fiber-based radar absorbing materials

By using skin collagen fiber (CF) as raw material,Schiff base structure containing CF (Sa-CF) was synthesized through CF-salicylaldehyde reaction.Then a novel radar absorbing material (Fe-Sa-CF) was prepared by chelating reaction between Sa-CF and Fe 3+.The coaxial transmission and reflection method was used to analyze the complex permittivity and complex magnetic permeability of these CF-based materials,and the radar cross section (RCS) method was used to investigate their radar absorbing properties in the frequency range of 1.0-18.0 GHz.Experimental results indicated that the conductivity of CF increased from initial 1.08×10-11 to 2.86×10-6 S/cm after being transferred into Fe-Sa-CF,and its dielectric loss tangent (tanδ) in the frequency range of 1.0-17.0 GHz also increased.These facts suggest that the Fe-Sa-CF is electric-loss type radar absorbing material.In the frequency range of 3.0-18.0 GHz,Sa-CF (1.0 mm in thickness) exhibited somewhat radar absorbing property with maximum radar reflection loss (RL) of-4.73 dB.As for Fe-Sa-CF,the absorbing bandwidth was broadened,and the absorbing intensity significantly increased in the frequency range of 1.0-18.0 GHz where a maximum radar RL of-9.23 dB was observed.In addition,the radar absorbing intensity of Fe-Sa-CF can be further improved by increasing membrane thickness.When the thickness reached to 2.0 mm,the RL values of Fe-Sa-CF were-15.0-18.0 dB in the frequency range of 7.0-18.0 GHz.Consequently,a kind of novel radar absorbing material can be prepared by chemical modification of collagen fiber,which is characterized by thin thickness,low density,broad absorption bandwidth and high absorption intensity.     

玻璃纤维增强塑料低温收缩率的测量

以二级G-M制冷机为冷源建立了15~293K温区的应变测量系统.采用应变片法测量了材料低温收缩率,分析并修正了低温下卡玛箔应变片电阻和灵敏系数变化对测量结果的影响.通过测量304不锈钢收缩率并与标准值比较,验证了系统测量的准确性且得出灵敏系数的修正系数随温度的变化关系.随后测量Al6061-T6的收缩率并与标准值对比,两者最大偏差为-4.8%,验证了修正系数的合理性.最后测量了玻璃纤维质量分数为70%的玻璃纤维增强塑料(GFRP)横向和纵向的收缩率.结果表明:同一温度范围内GFRP横向应变值为纵向应变值的1.12倍.     

基于人工神经网络的航空轴承疲劳可靠性分析

提出一种人工智能方法进行航空轴承疲劳可靠性分析.通过二次多项式近似拟合温度场效应,建立热弹流润滑效应下航空轴承接触应力分析模型,同时考虑热弹流润滑效应、材料属性以及疲劳强度修正系数的随机性,结合应力-强度干涉理论,运用人工神经网络法完成疲劳可靠性分析,基于改进的一次二阶矩法完成可靠性灵敏度分析.数值算例表明,建立的可靠性分析模型能正确反映热弹流润滑效应对航空轴承接触疲劳的影响.与传统蒙特卡罗方法相比,提出的智能方法具有良好的全局搜索能力和高效的计算性能,并通过无交互方差分析滚动轴承疲劳试验对可靠性灵敏度分析结果进行了验证.