利用等离子体增强原子层沉积技术(PE-ALD)在涂覆聚丙烯酸酯多元醇树脂有机涂膜的 PET基底上沉积一层无机薄膜得到功能性 PET复合膜.通过水蒸气透过率测试仪和紫外可见近红外分光光度计研究了有机涂膜厚度、PE-ALD 镀膜种类和 PE-ALD 镀膜温度对 PET 复合膜水蒸气阻隔性和透光性能的影响.结果表明:聚丙烯酸酯多元醇有机涂膜厚度对 PET复合膜的水汽阻隔性和透光率基本无影响;PE-ALD 沉积的 Al2O3 薄膜可大幅提高 PET复合膜的水蒸气阻隔性,且 PE-ALD镀膜温度为 100℃时,水蒸气阻隔性能最优,可达 0.17g·m-2·d-1.

研究了交联聚乙烯(XLPE)用3种低密度聚乙烯基体树脂的分子结构,考察其对XLPE在120?℃时挤出稳定性和升温交联过程中熔体流动性的影响.结果表明:端乙烯基不饱和双键含量较高的XLPE?C在120?℃时的挤出稳定性相对较差,交联速率较快,交联后的复数黏度和凝胶含量较高,凝胶含量可达90.0％.

在低温80℃的沉积条件下,采用等离子体增强原子层沉积(PEALD)技术在柔性聚对苯二甲酸乙二醇酯(PET)基底上制备氧化铝(Al2O3)阻隔薄膜.通过X射线光电子能谱、椭圆偏振仪测试分析表明,制备的Al2O3薄膜纯度较高,均匀性好.同时,通过调节沉积循环周期制备了不同厚度的Al2O3薄膜,研究了薄膜厚度对其表面形貌、表面粗糙度、透光率以及水汽透过率的影响.结果表明,沉积循环周期为500cycles时制备的Al2O3薄膜性能最为优异,表面粗糙度为1.52nm,400～1200nm波长范围内平均透光率为90.4％,水汽透过率为3.15×10-3g·m-2·d-1.

将受阻酚类抗氧剂4,4'-硫代双(6-叔丁基间甲酚)与低密度聚乙烯(LDPE)、交联剂DCP(过氧化二异丙苯)进行熔融共混,制备了一系列不同抗氧剂含量的交联聚乙烯(XLPE).研究了抗氧剂含量对XLPE交联过程、凝胶含量、氧化诱导期(OIT)、热老化前后力学性能及热延伸特性的影响.研究结果表明,添加抗氧剂可以延迟交联反应,降低XLPE的交联度,提高材料的氧化诱导期及热老化后的拉伸强度,使材料的热延伸性能增加.与无抗氧剂的样品相比,当抗氧剂含量为0.3％时,XLPE起始交联反应温度从155.2℃延迟至160.3℃,OIT由2 min延长至40 min;当抗氧剂含量从0增加到0.8％时,XLPE交联度由90％降至76.4％;热延伸伸长率由40％增大至131％.

采用热拉伸-高温退火-冷拉的拉伸工艺制备了交联聚乙烯微孔膜,考察了交联聚乙烯的交联度、拉伸温度、退火温度和冷拉等工艺条件对交联聚乙烯微孔膜成孔性能的影响,并对成孔过程和机理进行了探讨.交联聚乙烯的交联度显著影响成孔性能,随着交联度的增加,成孔性增加.拉伸温度在90?120 ℃时,膜片基本由纤维状晶构成.拉伸温度升至130 °C,并在此温度进行高温退火处理,膜片开始出现细缝状微孔.施加冷拉可以调控细缝状微孔形态演变,进一步被拉伸成圆形或椭圆洞状微孔.本文所用拉伸工艺为制备高性能聚乙烯微孔膜提供了一种新的思路,有助于开发自主知识产权的聚乙烯微孔膜技术,突破锂离子电池隔膜等高端聚乙烯微孔膜的国外技术垄断.

研究了2种国产电缆绝缘专用低密度聚乙烯(LDPE)2220H(分别记作LDPE A,LDPE B)的分子链段结构、动态流变性能、熔融结晶性能、体积电阻率和直流击穿强度.结果表明:LDPE A的相对分子质量和长支链含量高于LDPE B,相对分子质量分布相近;结晶度和熔融温度较高的LDPE A在较高温度条件下的体积电阻率高于LDPE B;LDPE A的特性击穿强度稍高于LDPE B;LDPE的电气性能与其长支链含量和结晶性能密切相关.

选用3种国内商品化的电缆用低密度聚乙烯(LDPE),利用凝胶渗透色谱仪、升温淋洗仪、红外光谱仪、差示扫描量热仪研究了其链结构和交联性能,探讨了相对分子质量及其分布、链支化、双键等因素对树脂结晶行为和交联性能的影响.结果表明:支链含量越少,亚甲基序列越长,结晶能力越强,其结晶度越高;端双键含量越高,其交联反应速率越快;凝胶含量高可能与树脂相对分子质量大、长支链含量高有关.

ABSTRACT Crosslinked polyethylene films were prepared and stretched at different temperatures (below and above melting temperature). The stretching temperature exhibited pronounced effects on the structure and puncture resistance of the films. Combining the results of differential scanning calorimetry, 1D X‐ray diffraction, 2D X‐ray diffraction, and scanning electron microscope, it was demonstrated that the film stretched above T m has lower crystallinity, thinner lamellar, and larger crystal grain size than that stretched below but near T m . All the stretched films showed highly oriented lamellae in the bulk and arranged perpendicular to the stretching direction. The crystals of the film stretched below T m were arranged in highly aligned microfibrils with distinct interlamellar boundary and the crystals of the film stretched above T m were arranged in a progressively less orderly manner with increased interlamellar entanglement. Due to this structure difference, the puncture resistances of the films stretched above T m were much larger than that stretched below T m . © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47542.

以HDPE为原料,利用化学交联方法和热致相分离原理制备交联聚乙烯(XLPE)微孔膜.研究了稀释剂含量对XLPE材料流变性能、熔融结晶性能和成孔性能的影响,同时考察了XLPE微孔膜的耐热性.结果表明,稀释剂的含量越高,可控XLPE的加工性越好,安全加工窗口越宽.XLPE膜片的凝胶含量、熔点、结晶度等性能参数均随稀释剂加入量的增加而降低.XLPE微孔膜破膜温度比现有湿法UHMWPE膜片的破膜温度提高了30℃,耐热性优异,在拓宽锂离子电池隔膜安全窗口、提高锂离子电池安全性上有潜在应用价值.

Normal liquid paraffin,high boiling point liquid paraffin and n-hexadecane were used as diluent for the preparation of crosslinked polyethylene microporous membrane.The effects of diluent on the membrane crosslinking and pore performance were investigated.The crosslinking degree was decreased with increasing content of diluent.At the same content of diluent,the crosslinking degree was basically identical.High boiling point diluent can effectively avoid bubble defects on the membrane surface.The porosity of crosslinked membrane after extraction process was lower for n-hexadecane compared to high boiling point liquid paraffin.It was found that n-hexadecane was involved in the high temperature crosslinking reaction process comfirmed by TG and DSC testing.

A novel system and method for removing heat from batteries, capacitors and other energy storage devices during high rate or multi-cycle operation has been proposed in this work. By modifying the exposed posts and inter-cell connecting bus-bars, heat transfer will be increased thus reducing the operating temperature of the battery. Because valve-regulated lead-acid (VRLA) batteries generate higher levels of internal heat, and because they have a lower thermal mass and lower heat transfer properties, these modifications are particularly valuable for these types of batteries. This thermal management technology can be used to improve the operating life of large batteries such as VRLA stationary batteries used for UPS and standby power applications. In very high-power energy storage applications such as load-leveling, peak-shaving or spinning reserve, battery life may be increased to as much as two times by reducing the operating temperature ten degrees centigrade using these proposed concepts.