微纳层叠挤出技术的研究进展

综述了近年来微纳层叠挤出技术及其制品性能,重点介绍了国内外微纳层叠挤出技术发展历程及微纳层叠挤出制品在力学性能、光学性能、阻透性能、导电性能等方面的研究进展,为今后微纳层叠挤出技术的研究以及开发新型功能复合材料提供依据。     

基于微纳层叠技术的聚合物纳米纤维制备及应用研究进展

简述了微纳层叠共挤技术的发展;总结了近些年来基于微纳层叠技术制备纳米纤维的研究进展,包括聚合物参数,制备方法和成纤机理;对目前几种典型微纳层叠成纤方法进行了分类和对比,并对纤维的性能进行了阐述;对微纳层叠纳米纤维的应用进行了介绍。最后针对微纳层叠技术用于纳米纤维制备的发展方向和应对的挑战进行了浅析。     

环形微纳层叠挤出模具的结构设计与流场分析

微纳层叠挤出技术通过对高聚物材料微观形态进行调控来提高多方面的性能,例如力学、阻隔性能等。针对目前微纳层叠挤出技术中层叠模具单位体积内层叠单元较少,流量较低的情况,提出了一种将层叠单元进行环向布置的创新设计思想。设计了用于环向布置的层叠单元流道结构,并提出了模具内单组层叠单元环向布置与多组层叠单元环向布置的具体方案。设计表明,在相同体积下该结构可以布置更多的层叠单元,流量是传统设计的4倍。同时,流道长度为传统设计的60%。利用Polyflow软件对层叠单元的流道进行了数值模拟,结果表明流道压力和速度分布均匀,整体压力降较低。     

微纳层叠技术对线性低密度聚乙烯材料性能的影响

采用实验室自主设计的微纳层叠挤出成型设备,制备了1层、9层和81层的线性低密度聚乙烯(LLDPE)实验样品,并对不同层数的样品进行取向度、结晶度以及拉伸强度测试,主要研究了微纳层叠技术对聚合物分子链取向、结晶度以及拉伸强度的影响。实验结果表明:通过微纳层叠技术,提高了LLDPE的结晶度,9层、81层LLDPE的结晶度较1层LLDPE结晶度的38.56%分别提高到50.62%和54.42%;同时还提高了LLDPE沿挤出方向(MD)和垂直于挤出方向(TD)的取向度和拉伸强度,具有双向拉伸作用,且扭转层叠单元的使用个数越多,双向拉伸效果越明显。     

微纳叠层功能复合材料模内制备新方法

介绍微纳叠层功能复合材料制备方法的发展历程及最新进展,介绍微纳叠层功能复合材料模内制备新方法、新型叠层器的工作原理以及技术优点.同时介绍了微纳叠层功能复合材料在阻隔性能、光学性能、力学性能、导电性能等方面的优异性能.     

微纳层叠挤出CNTs/HIPS复合材料的介电与导电性能

利用自制的微纳层叠挤出装置制备了CNTs含量为1%、3%时的1、9、81、729层的碳纳米管/高抗冲聚苯乙烯(CNTs/HIPS)多层复合材料,研究了微纳层叠挤出技术对复合材料介电与导电性能的影响。结果表明:随着层数的增加,低频下交流电导率轻微下降,而介电常数得到明显提高。CNTs含量为3%的试样在100 Hz时,9、81、729层试样的介电常数比1层试样的介电常数依次提高了25.4%、63.4%、135.2%。分析表明:这归结于微纳层叠挤出过程中的剪切及拉伸作用使CNTs在HIPS基体中发生取向,且随着层数的增加,取向效果越明显,碳纳米管的取向造成导电网络被破坏,导致交流电导率轻微下降,但可形成更多的微电容结构,提高了复合材料的介电常数。     

微纳多层功能复合材料的制备新技术

介绍了微纳多层共挤出技术是通过简单地对高分子熔体进行分割-变流-合并过程来增加层数的技术。说明通过微纳多层共挤出技术制得的微纳交替多层复合材料在结构上不同于传统加工方法制得的复合材料,其力学性能、阻隔性能、导电性能、光学性能具有独特的优点。指出微纳多层共挤出技术还可用于开发新型的中间相材料;这种交替多层结构形态为界面张力、粘接、结晶、扩散等理论研究提供了一个很好的模型。     

微纳层叠共挤PP/PA6/CNTs原位微纤复合膜的制备及性能研究

采用双转子连续混炼挤出机与微纳层叠共挤出成型设备制备了聚丙烯/聚酰胺6/碳纳米管（PP/PA6/CNTs）复合材料和原位微纤复合膜,通过扫描电子显微镜（SEM）、流变仪、差示扫描量热仪（DSC）、万能拉伸试验机及电阻测试仪对其微观结构、流变性能、结晶性能、力学性能和导电性能进行了表征。结果表明,与共混相比,微纳层叠共挤出法使得分散相PA6/CNTs形成了微纤,微纤的形成不仅提升了复合膜的动态流变性能,并且增加了基体PP相的结晶度,提高了PA6相的结晶温度,提升了复合膜的结晶性能;当CNTs含量为0.5 %（质量分数,下同）时,复合膜的拉伸强度和断裂伸长率均达到最大值,分别为42.17 MPa和857.82 %,体积电阻率（R）下降到10⁴ Ω·cm,综合力学性能和导电性能达到最佳。     

基于微纳层叠技术的PVC分子取向对增塑剂迁移的影响

利用自制微纳层叠装置在挤出过程中对聚合物薄层产生的持续剪切作用,分别制备了3种具有不同取向程度的聚氯乙烯（PVC）片材。利用扫描电子显微镜、万能试验机等对PVC片材的性能进行了表征。结果表明,与不经层叠器挤出的试样相比,经2节层叠器和4节层叠器的试样沿挤出方向的拉伸强度分别提高了5.72 %和10.18 %,密度分别提高了2.81 %和4.35 %,挥发损失率分别降低了13.12 %和37.65 %。     

基于薄片层叠技术的制氢燃料处理系统研究进展

阐述了基于薄片层叠技术的制氢燃料处理系统的研究进展,通过对制氢燃料处理系统原理的介绍,从薄片层叠的关键技术——微通道结构、流道分布、薄片层叠连接方法和薄片材料4个方面重点分析了薄片层叠技术在制氢燃料处理系统的应用优势,为薄片层叠技术应用于制氢燃料处理系统提供了设计依据,并对层叠技术在制氢燃料处理系统的应用前景进行展望。     

PP／纳米CaCO3发泡板材的性能和泡孔结构的研究

利用纳米CaCO3对聚丙烯（PP）的增强增韧作用，采用合理的成型工艺及设备，挤出成型了性能优越的发泡板材。详细研究了CaCO3粒子对板材力学性能的影响，研究表明：纳米CaCO3粒子的含量接近4％时（相对PP），粒子在基体中的分散良好，复合材料的拉伸强度和冲击强度达到最大值；纳米粒子是否经过表面处理，只对材料冲击强度的影响产生不同效果；微米CaCO3粒子含量小于5％时（相对PP），对板材的性能影响很小，但超过该含量后，板材的性能明显下降。     

Effect of Silicone Nano,Nano/Micro and Nano/Macro‐Emulsion Softeners on Color Yield and Physical Characteristics of Dyed Cotton Fabric

The study of silicone nano‐emulsions and softeners to alter physical properties of undyed cotton fabric has recently gained a substantial interest. However, systematic investigation of silicon nano‐emulsion softeners on dyed cotton fabric has not so far been conducted. This paper deals with the application of silicone nano‐, micro‐, and macro‐emulsion softeners, and combinations of nano/micro and nano/macro, on dyed cotton fabric. We report the effect of silicon nano/micro‐ and nano/macro‐emulsion softeners on color yield and physical characteristics of dyed cotton fabric. All bleached fabrics were dyed with CI Reactive Black 5 and then treated with known concentrations of silicone softeners by the pad‐dry method. The silicone nano‐emulsion was combined with micro‐ and macro‐emulsion softeners using blending ratios of nano/micro (1:1) and nano/macro (1:1). Treated fabrics were compared in terms of physical properties such as fabric handling, wrinkle recovery angle, bending length, abrasion resistance and tensile strength. The color changes were evaluated by color yield (K/S) values and total color difference (ΔE_cmc). The results revealed that the silicon nano‐emulsion had better physical properties than micro‐, macro‐ and combination nano/micro‐ and nano/macro‐emulsion softeners. Among all treated samples, nano‐emulsion softeners showed better ΔE_cmc values. Scanning electron microscopy analysis suggests that the fiber morphology of treated fabrics was very smooth and uniform.     

PTFE微粉对长链烷基硅油润滑膏摩擦学性能的影响

采用不同粒径的聚四氟乙烯(PTFE)微粉添加到长链烷基硅油中,制成润滑膏。利用四球摩擦磨损试验机考察了PTFE微粉的粒径及添加量对长链烷基硅油润滑膏摩擦学性能和烧结负荷性能的影响。结果表明,微、纳米PTFE微粉既可作为长链烷基硅油的增稠剂,又可作为固体润滑剂,对长链烷基硅油润滑膏的抗磨减摩性能有一定的改善,对其烧结负荷性能有很大提高;微、纳米PTFE微粉在长链烷基硅油中的较佳质量分数分别是40%和28%。     

Comparison of cure characteristics and mechanical properties of nano and micro silica‐filled CSM elastomers

In this study, the effect of micro and nano silica and their combination on mechanical and thermal properties of Chlorosulfonated Polyethylene compounds were investigated. Cure characteristics were studied using a Monsanto Moving Die Rheometer at 155°C. Incorporation of nano silica accelerated the vulcanization whereas the micro silica particles decelerated the curing process. Both micro and nano silica increased the crosslink density as evidenced by swelling test. However, this value has been more improved in CSM/nano silica composites. The physico‐mechanical properties of CSM/nano silica are superior compared to CSM/micro silica. Nano silica provided reinforcing efficiency which is not only because of higher specific surface area but also because of various interactions and especially physical interactions which are discussed in the text. Nano silica particles also improved the thermal properties more efficiently. Incorporation of 15 phr (part per hundred) nano and 5 phr micro silica to polymer improved the initial decomposition temperature for about 51°C and 16°C, respectively, using a TGA. The combination of micro and nano silica, showed that by coupling nano and micro fillers, the loading of fillers can be minimized. In other words, the hybrid samples with a lower filler loading behave as efficient as their separate counterpart with higher loading. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42668.     

Mechanical properties study of micro‐ and nano‐hydroxyapatite reinforced ultrahigh molecular weight polyethylene composites

This is a comparative study between ultrahigh molecular weight polyethylene (UHMWPE) reinforced with micro‐ and nano‐hydroxyapatite (HA) under different filler content. The micro‐ and nano‐HA/UHMWPE composites were prepared by hot‐pressing method, and then compression strength, ball indentation hardness, creep resistance, friction, and wear properties were investigated. To explore mechanisms of these properties, differential scanning calorimetry, infrared spectrum, wettability, and scanning electron microscopy with energy dispersive spectrometry analysis were carried out on the samples. The results demonstrated that UHMWPE reinforced with micro‐ and nano‐HA would improve the ball indentation hardness, compression strength, creep resistance, wettability, and wear behavior. The mechanical properties for both micro‐ and nano‐HA/UHMWPE composites were comparable with pure UHMWPE. The mechanical properties of nano‐HA/UHMWPE composites are better compared with micro‐HA/UHMWPE composites and pure UHMWPE. The optimum filler quantity of micro‐ and nano‐HA/UHMWPE composites is found to be at 15 wt % and 10 wt %, separately. The micro‐ and nano‐HA/UHMWPE composites exhibit a low friction coefficient and good wear resistance at this content. The worn surface of HA/UHMWPE composites shows the wear mechanisms changed from furrow and scratch to surface rupture and delamination when the weight percent of micro‐ and nano‐HA exceed 15 wt % and 10 wt %. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42869.     

Characterization of the fracture behavior and viscoelastic properties of epoxy-polyamide coating reinforced with nanometer and micrometer sized ZnO particles

The mechanical and viscoelastic properties of an epoxy-polyamide coating containing nano and micro sized ZnO particles were studied. The nanocomposites were prepared at different loadings of the nano sized ZnO particles. The composites were also prepared using micro sized ZnO particles at different lambdas (lambda (λ) = PVC/CPVC). The optical properties of each nanocomposite were studied by UV–vis technique. Dynamic mechanical thermal analysis (DMTA) and micro-Vickers were used to investigate the mechanical properties of the composites. The viscoelastic properties of the composites were studied by a tensile test. The fracture morphologies of the composites were studied by a scanning electron microscope (SEM). An increase in Tg together with a decrease in cross-linking density of the composites was obtained when the coating was reinforced with the micro sized ZnO particles. On the other hand, the Tg and cross-linking density of the composites were decreased using nano sized ZnO particles. It was also found that, the Young's modulus and the fracture energy of the coating were decreased using micro and nano sized ZnO particles. The greater toughness as well as fracture energy of the composite was obtained when it was reinforced with the nano sized ZnO particles. The curing behavior of the epoxy coating was affected in the presence of the micro and nano sized ZnO particles.     

Preparation of micro/nano encapsulated phase change materials（PCM）and application to building

相变储能微/纳米胶囊在能源科学等领域发挥着日益重要的作用。本文系统介绍了相变微/纳米胶囊的制备方法,其中,相变储能微胶囊的制备方法主要包括界面聚合法、原位聚合法、凝聚法、悬浮聚合法等;相变储能纳米胶囊的制备方法主要包括细乳液聚合法和原位聚合法。着重阐述了相变储能微/纳米胶囊在现在建筑中的应用,主要是在混凝土、墙体、墙板及地板中的应用。提出目前存在的问题,如相变储能墙体在夏天高温时无法完成相变过程,及相应的解决方法。指出未来将以合成工艺优化、强化胶囊理化性能和改善与无机建筑材料相容为重点研究方向。     

相变储能微/纳米胶囊的制备及其在建筑中的应用研究进展

相变储能微/纳米胶囊在能源科学等领域发挥着日益重要的作用。本文系统介绍了相变微/纳米胶囊的制备方法,其中,相变储能微胶囊的制备方法主要包括界面聚合法、原位聚合法、凝聚法、悬浮聚合法等;相变储能纳米胶囊的制备方法主要包括细乳液聚合法和原位聚合法。着重阐述了相变储能微/纳米胶囊在现在建筑中的应用,主要是在混凝土、墙体、墙板及地板中的应用。提出目前存在的问题,如相变储能墙体在夏天高温时无法完成相变过程,及相应的解决方法。指出未来将以合成工艺优化、强化胶囊理化性能和改善与无机建筑材料相容为重点研究方向。     

炸药纳微米结晶品质控制技术研究

为研究纳微米炸药的结晶习性及晶形控制技术,结合经典结晶理论和无序结晶理论,从晶体生长热力学及动力学角度研究纳微米炸药重结晶的特性。通过控制溶剂—非溶剂法细化炸药过程中晶体生长的条件,介入模板粒子,均可有效地控制纳微米炸药粒子的晶形及粒径。