Tencel纤维纱线染色生产实践

指出了Tencel纤维的特点，介绍了Tencel纤维纱线的染色和原纤化处理的新工艺。     

Human Serum Transferrin Fibrils: Nanomineralisation in Bacteria and Destruction of Red Blood Cells

Fibrils formed by human serum transferrin [(1–3 μM ) apo‐Tf, partially iron‐saturated (Fe_0.6‐Tf) and holo‐Tf (Fe₂‐Tf) forms], from dilute bicarbonate solutions, were deposited on formvar surfaces and studied by electron microscopy. We observed that possible bacterial contamination appears to give rise to long, pea‐pod‐like (PPL) structures for Fe₂‐Tf, attributable to the formation of polyhydroxybutyrate (PHB) storage granules, under the nutrient‐limiting conditions used. These PPL structures contained periodic nanomineralisation sites susceptible to uranyl stain. Extended incubation of transferrin solutions (about four days) gave rise to extensive transferrin fibril structures. Optical microscopy and AFM studies showed that red blood cells (RBCs) readily adhere to these fibrils. Moreover, the fibrils appear to penetrate RBC membranes and to induce rapid cell destruction (within about 5 h). It is speculated that in situations in vivo where transferrin fibrils can form, such interactions might have adverse physiological consequences, and further studies could aid the understanding of related pathological events.     

氮丙啶化合物抑制Lyocell纤维原纤化

针对Lyocell纤维出现的原纤化问题,尝试用氮丙啶基化合物作为Lyocell纤维的交联剂抑制原纤化趋势,试验证明有比较好的抗原纤化能力,并适合在线交联。经过摩擦试验等证明氮丙啶化合物能起到较好的交联作用,提高湿摩擦时间,并且对Lyocell纤维原有的力学性能影响不大。     

Shear‐induced fibrillation and resultant mechanical properties of injection‐molded polyamide 1010/isotactic polypropylene blends

It is feasible to control the phase morphology and orientation for immiscible polymer blends to manipulate their properties. In this paper, the blend of polyamide 1010 (PA1010) and isotactic polypropylene (iPP) (mainly at a fixed ratio of PA1010/iPP = 80/20) was used as an example to demonstrate the effect of shear on the morphology and resultant mechanical properties. After being melt blended, the injection‐molded bars were prepared via a dynamic packing equipment to impose a prolonged shearing on the melts during the solidification stage. By controlling the shear time, the structure evolution and morphological development of the blends can be well controlled. Mechanical measurement of the molded bar showed a dramatically improved tensile property and impact strength with increasing shear time. Morphological examination revealed that the iPP droplets are elongated and become thin fibrils along the shear direction with increasing shear time. The shear‐induced fibrillation, instead of orientation, is believed to be responsible for the largely improved properties of the blend, particularly for the impact strength. The toughening mechanism is discussed based on the combined effect of hindrance of crack propagation and the transferring and bearing of the load due to the existence of the fibrils. This was further proved by changing the blending ratio and using low molecular weight iPP. Finally, we propose a concept for designing blending materials with good comprehensive properties. Copyright © 2011 Society of Chemical Industry     

Fabrication of polyamide 12T micro-cellular foams with ultra-high compressive strength via in situ polytetrafluoroethylene fibrillation using supercritical carbon dioxide foaming

The development of micro-cellular foams with ultra-high compressive strength and high volume expansion ratio (VER) is a challenging task. Herein, polyamide 12T (PA12T) micro-cellular foams with ultra-high compressive strength were fabricated via in situ polytetrafluoroethylene (PTFE) fibrillation using supercritical CO₂ foaming technology and a chain extender. The resulting branched structure showed considerably improved viscoelasticity and foaming performance, thus improving the cell morphology of the PA12T foam and exhibiting high VER. The PTFE fibrillation network induced melt strength enhancement, crystallization nucleation, and cell nucleation. The branched PA12T foam with 1.5 wt% PTFE exhibited the smallest cell diameter (15 μm) and highest cell density (3 × 10⁹ cells/cm³). The compressive strength of the foam (0.50 MPa under 5% strain) was 70% higher than that of pure PA12T. This research offers an effective method for producing high-VER PA12T foams with adjustable micro-cellular structures and excellent mechanical properties.     

Direct Observation of Cavitation and Fibrillation in a Probe Tack Experiment on Model Acrylic Pressure-Sensitive-Adhesives

The adhesion mechanisms of two acrylic Pressure-Sensitive-Adhesives on a stainless steel probe are investigated with a custom-designed probe tack apparatus. Our setup allows the simultaneous acquisition of a nominal stress and strain curve, and the observation of the adhesive film from underneath the transparent substrate. The temperature was varied in the range -20°C to 50°C and the debonding rate in the range 1–10000 μm/s. For all conditions we observed, upon debonding, the formation of cavities at or near the interface between the probe and the film. These cavities initially grew predominantly in the plane of the film but, at higher values of nominal strain, the walls between the cavities were stretched in the direction normal to the plane of the ifim to become a fibrillar structure. The transition from a cavitated structure to a fibrillar one was only found within a time-temperature window of rheological properties of the adhesive, while the adhesion energy was found to be mainly related to the elongational properties of the adhesive. The maximum tensile stress observed in the probe tack experiment was directly related to the appearance of the cavities and showed a good correlation with the shear modulus of the adhesive, while the adhesion energy was found to be mainly related to the elongational properties of the adhesive. The presence of 2% acrylic acid as a comonomer had a negligible effect on the maximum stress but a very important one on the formation of a fibrillar structure and on the locus of failure.     

心内膜微波逐点房颤消融术的温度场研究

根据实际临床需求, 针对房颤微波消融中常见的逐点消融术, 探究时间功率和天线距离对相邻2个消融点消融效果的影响, 找出最佳的消融功率和最佳天线距离, 为临床治疗提供参考.构建了包括血液、心肌、脂肪的3层模型, 采用2.45 GHz频率进行了电磁热耦合计算并得到了心肌中温度的分布.功率采取30、40、50和60 W, 2个消融点之间的距离采取0.5、1、1.5和2 cm.结果表明:功率为30 W和40 W时会导致消融区域比较小;功率为60 W时会导致最高温度过高且消融的范围与功率为50 W的时候相比并没有显著的提升;相邻2个消融点间距为0.5cm和1 cm时会导致总消融区域比较小且最高温度过高;间距为2 cm时无法形成连续透壁的消融区域.因此50 W是最佳消融功率, 1.5 cm是最佳消融2点间距, 可以在保证最高温度不过高、连续透壁的情况下, 获得比较大的总消融区域和较高的能量利用效率.在50 W、1.5 cm的最佳消融方案下, 逐点消融2个点所需要的总消融时间为43.2 s, 最高温度为87.2℃, 连续透壁消融长度、心肌内部最大消融长度及最大消融宽度分别为2.486、2.770、1.865 cm.     

分散相含量对POE/PTT原位成纤增强复合材料性能的影响

采用微纳叠层共挤制备了乙烯-辛烯共聚物/聚对苯二甲酸丙二醇酯（POE/PTT）原位成纤复合材料,通过扫描电子显微镜分析了分散相PTT含量对其在基体中的形态及分布的影响;讨论了PTT含量对复合材料静态力学性能的影响,利用差示扫描量热仪分析了PTT对POE基体结晶性能的影响。结果表明,随着分散相含量的提高,PTT微纤的数量逐渐增加,降低了POE基体的结晶度,当POE/PTT质量比为85/15时,拉伸强度较纯POE提高了16.9 %。     

微孔发泡PP/PET/CNTs复合材料的制备及其电磁屏蔽效能研究

采用聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、碳纳米管(CNTs)制备了具有纤维结构的微孔发泡复合材料,借助层叠器内部流道的变化,实现了造粒阶段PET的连续化原位成纤.通过差示扫描量热仪(DSC)、扫描电子显微镜(SEM)、矢量网络分析仪和万能试验机对复合材料的结晶性能、表观形态、电磁屏蔽效能(EMI SE)和拉...     

Effects of alkali pretreatment on lyocell woven fabric and its influence on pilling properties

Abstract

Experiments were conducted to study the influence of various concentration of alkalis on the pilling properties of lyocell fabrics. Generally, the lyocell fabric has more tendency of pill formation due to fibrillation properties. Therefore, present work is focused on the impact of alkali pretreatments with various concentration from 0.5?mol/L to 3?mol/L on lyocell with their pilling resistance. Due to the morphological changes, pilling results are attributed to the alkali types and their concentration. Treatment with TmAH and LiOH at 2?mol/L shows the reduction of a number of fibrils leading to reduce the pill generation significantly. Carboxyl content and iodine sorption value are analyzed to find the impact of alkali on the accessible region and structural changes respectively, also surface modification was observed by SEM to confirm the surface characteristics. Overall results shows that the reduction of fibrillation leads to better pilling resistance of lyocell fabric.