聚偏氟乙烯在锂离子电池中的应用

综述了PVDT作作为粘结剂和隔膜在锂离子电池中的应用。并介绍了电极和隔膜的制作方法。     

聚偏氟乙烯制备锂离子电池隔膜初探

综述了锂离子电池隔膜的现状及其存在的问题,以及制备锂离子电池隔膜的新材料与发展现状;介绍了锂离子电池隔膜的结构特点与性能要求;对聚偏氟乙烯制备锂离子电池隔膜的方法及其改性技术进行了初步的探讨。     

PVDF黏结剂含量对锂离子电池正极 浆料流变性能的影响研究

制备了3种具有不同聚偏四氟乙烯（PVDF）黏结剂含量的锂离子电池正极浆料,并对它们的流变性能做了测试和比较。结果表明,随着PVDF黏结剂含量的提高,浆料的黏度变大,流动性变差。触变性测试结果还表明,只有当加入适量的PVDF时,浆料中的颗粒之间才能形成稳定均匀的浆料,过多或者过少都会导致颗粒间的团聚产生。     

聚偏氟乙烯/聚醚酰亚胺共混溶液的流变性能研究

采用二甲基乙酰胺(DMAc)为溶剂配制不同共混比的聚偏氟乙烯(PVDF)和聚醚酰亚胺(PEI)共混溶液,用锥板式黏度计研究了PVDF/PEI共混溶液的流变性能。结果表明:PVDF/PEI共混溶液表观黏度与剪切速率呈线性相关;当PVDF/PEI质量比为9/1时,共混溶液的零切黏度明显降低,非牛顿指数和黏流活化能出现极值;随着PEI含量的增加,黏流活化能急剧增大。     

聚偏氟乙烯熔体的流变特性

综述了聚偏氟乙烯树脂的性能、其熔体的流变特性及在熔融加工领域的广泛应用,详细介绍了剪切变稀的非牛顿流体流变行为及其影响因素。通过分子链支化、共混和共聚可改善PVDF熔体的流变性能,以满足不同性能制品的需求以及进一步拓宽熔融加工成型方法。     

俄产聚偏氟乙烯树脂性能及用途

介绍了俄罗斯生产的聚偏氟乙烯Ф-2和改性聚偏氟乙烯Ф-2М的性能、加工成型方法及其用途。Ф-2和Ф-2М分别具有CH2—CF2m和(CH2—CF2)n—(CF2—CF2)m分子结构的结晶聚合物,其加工成的制品具有着优异的综合性能。该聚合物属于热塑性含氟高分子材料,可采用模压、挤出和压铸等通用的常规方法进行加工成型。     

聚偏氟乙烯树脂

１概述 聚偏氟乙烯（ＰＶＤＦ）树脂是氟树脂系列中第二大产品,是由偏氟乙烯单体均聚或共聚而成的含氟多功能材料,是７０年代发展起来的具有优良综合性能的新产品。目前世界年产量约为２万吨,仅次于聚四氟乙烯的第二大氟化工产品。 ＰＶＤＦ是一种热塑性树脂,为线型结晶性聚合物,树脂呈白色粒状或粉末状,粒状树脂是供模压、注射、挤出用的,粉末状的则用作涂料。由于氟碳链的结合能高,所以具有良好的耐热、耐腐蚀性能,可在－４０～１５０℃下使用不变形;ＰＶＤＦ的化学稳定性良好,能耐氧化剂、酸、碱、盐类、卤素、芳烃、脂肪及氯…     

葡萄糖对聚偏氟乙烯膜性能的影响

用相转化法制备了聚偏氟乙烯/葡萄糖共混膜。当聚偏氟乙烯质量分数为10%,葡萄糖质量分数为4%时,膜的水通量和孔隙率最高,为33.1 mL/(cm2.h)和92.6%;接触角也由92°减小为72°,显示出很好的亲水性。并对共混膜的微观结构、XRD、红外光谱和热稳定性进行了详细的研究,讨论了聚偏氟乙烯和葡萄糖的共混机理。     

聚偏氟乙烯共混隔膜的制备与性能

以乙二醇二甲基丙烯酸酯和丙烯腈为单体,合成了聚合物poly(AN-co-PEGDMA),然后与聚偏氟乙烯(PVDF)共混,制备了不同poly(AN-co-PEGDMA)含量的PVDF/poly(AN-co-PEGDMA)共混隔膜,利用X射线衍射、扫描电子显微镜(SEM)、差示扫描量热对共混隔膜的性能进行表征。结果表明,随着poly(AN-co-PEGDMA)含量的增加,PVDF/poly(AN-co-PEGDMA)的玻璃化转变温度逐渐提高,衍射峰的谱峰强度逐渐降低,隔膜的结晶度降低。SEM结果显示,随着poly(AN-co-PEGDMA)含量的增加共混隔膜的孔隙变大,有利于电解液的有效吸收。通过对PVDF/poly(AN-co-PEGDMA)共混隔膜电导率、吸液率的测定,表明在poly(AN-co-PEGDMA)质量分数为30%时,制得的共混隔膜的性能较佳。在此基础上,对共混隔膜构建的聚合物锂离子电池的电化学稳定窗口、电池容量和循环性能进行测试,其电化学稳定窗口为0～4.7 V(vs Li+/Li),放电电容为1.433～1.151 mAh,可以满足商业使用要求,具有广阔的应用前景。     

聚碳酸酯对聚偏氟乙烯结构和结晶行为的影响

通过熔融共混法制备聚偏氟乙烯/聚碳酸酯（PVDF/PC）共混物,采用X线衍射仪（XRD）和差示扫描量热仪（DSC）表征共混物的结构、熔融和结晶行为.考察不同聚碳酸酯含量对聚偏氟乙烯晶体结构、熔点以及晶体完善程度等的影响.同时通过Avram i方程和结晶速率系数的研究,探讨PC对PVDF非等温结晶动力学的影响.研究结果表明：PC的掺杂没有改变PVDF的晶体结构,但是高PC质量分数（70%以上）却不利于PVDF晶体的生成;随着PC质量分数的增加,生成的PVDF晶体完善程度逐渐降低;当PC质量分数在70%以下时,PC起到类似成核剂作用,提高PVDF结晶速率.     

烧结法生料浆流变性的研究

为了降低烧结法氧化铝生产中烧结过程的能耗,从流变学角度测量生料浆在6个不同剪切速率下的剪切应力,通过其流变曲线,研究了生料浆的触变性及水分质量分数、温度、表面活性剂对生料浆流变性的影响。结果表明:含水质量分数为35%的生料浆具有触变性;随着生料浆含水质量分数从34.7%增加到39.7%、温度从40℃升高到80℃,添加适当表面活性剂R—COONa,可降低生料浆的屈服应力和表观粘度,使生料浆的流动性得到一定改善。     

依兰煤油煤浆流变特性的初步研究

在常压和30-70℃的条件下,采用旋转式粘度计测定了依兰煤油煤浆体系的表观粘度,考察了油煤浆体系的表观粘度随溶剂种类、煤颗粒直径、煤浆浓度、温度以及剪切速率等因素的变化规律,建立了实验条件下煤浆体系的流变方程。结果表明：依兰煤油煤浆体系的流变特性符合幂定律模型。     

水合物浆液流动与流变特性研究进展

水合物浆液技术作为一门新型水合物防治途径和油-气-水多相安全混输的方式逐渐受到油气生产和运输部门的重视。系统综述了国内外水合物浆液流动特征和流变特性的最新研究进展, 主要从研究装置、宏观形态演化、流率/压阻等其他流动参数变化规律及水合物浆液流变性方面进行了详细讨论。介绍了高压流变仪、高压黏度计及水合物流动循环管路等实验装置, 着重分析了水合物循环管路的优缺点;阐述了水相中水合物浆液和油水体系内天然气水合物浆液宏观形态演化的异同;系统研究了水合物形成过程中体系流量/压阻等其他流动参数变化规律;归纳总结了水合物浆液流变性实验和理论模型的研究成果。     

Effect of structure development on the rheological properties of PVDF/HNBR-based thermoplastic elastomer and its vulcanizates

The present work demonstrates the structure-rheology relationship of novel polyvinylidene fluoride/hydrogenated nitrile rubber blends with special reference to the effect of mixing time, which has not been amply discussed in the literature. In between 50 and 70 wt% rubber content, a yield in complex viscosity and secondary plateau in storage modulus were discerned due to interconnected droplets-matrix morphology manifesting the thermoplastic elastomeric nature of the blends (TPEs). Such network-like structure altered the rheological properties like relaxation time, capillary viscosity, die swell, elastic responses of the TPE with respect to the trend as expected according to the rule of mixing. Interestingly, in the early stages of mixing, when the dispersed size was bigger, the effect of physical network on the rheological properties was suppressed. During dynamic vulcanization (TPV), both lower and higher frequency responses in oscillatory shear flow, steady shear rheological properties, recoverable strain etc. have changed notably with mixing time. For example, although the complex viscosity of the TPV was higher at a lower frequency as compared to its TPE, it was significantly lower at a higher frequency at the beginning of dynamic curing; however, viscosity increased appreciably with time. Temperature-dependendent rheological properties were also influenced with mixing time of the compositions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48758.     

中国直接液化油煤浆及液化残渣流变特性研究进展

在煤直接液化工艺中,油煤浆和液化残渣的流变特性参数是工艺设计的重要基础数据之一。本文总结了我国液化油煤浆在常压常温、常压升温和加压升温条件下流变特性的研究进展和相应的流变模型,介绍了溶剂的性质、煤在溶剂中的溶胀、煤的热溶产物或初始液化反应产物等对煤浆体系黏度变化的影响,对开展我国液化油煤浆和液化残渣的流变特性研究,具有一定的指导意义。     

Effect of ball-milling parameters on the rheological properties of mold powder slurry

In this study, mold powder slurries with high solid loading and low viscosity were prepared during the ball-milling process for improving the homogeneity and mechanical properties of granules after spray-drying. The effect of ball-milling parameters, such as solid loading, binder/dispersant content, and ball-milling time, on the flowability, dispersibility, stability, and rheological behavior of mold powder slurries was systematically investigated by rheology observation and sedimentation tests. As these parameters varied, the slurry exhibited the shear-thinning behavior of a non-Newtonian fluid with a shear rate range of 0–50 s^?1, which was adequately described by the Herschel-Bulkley model. The optimal parameters that optimized the flowability, dispersibility, and stability of the slurry, along with its rheological behavior, were chosen as follows: solid loading, 60 wt%; modified sodium carboxymethyl cellulose binder content, 1.0 wt%; sodium tripolyphosphate dispersant content, 0.5 wt%; ball-milling time, 60 min.     

天然气水合物浆体流变性与安全流动边界研究进展

水合物安全流动技术作为一种新型的天然气运输管理方法具有广阔的发展前景,本文在综述国内外天然气水合物安全流动研究的基础上,分析了管道流动天然气水合物生成机理、特点和对油气管道的不利影响以及现有水合物安全流动研究存在的问题,包括实验管道长度较短、着重流动规律的研究而缺乏对流动边界的拓展等。进而对国内外天然气水合物低剂量抑制剂(low dosage hydrate inhibitor,LDHI)在保障天然气水合物安全流动、拓展天然气水合物安全流动边界以及螺旋流携带研究进行了总结评述;随后提出了利用螺旋流悬浮输送技术保障天然气水合物安全流动、拓展流动边界的新型方法。结合实验结果分析表明:螺旋流动从宏观上改变水合物浆体流动特点、有效提高水合物浆液的输送浓度并可拓展水合物安全流动边界。     

生物质水煤浆流变特性研究

以福建无烟煤、水葫芦、添加剂等制备生物质水煤浆,研究了其流变特性。结果表明：添加3％～3．5％的水葫芦及1％的分散剂制得的生物质水煤浆粘度在0．8～1．2Pa·s之间,且稳定性较好。生物质含量提高,生物质水煤浆的粘度逐渐上升;分散剂含量为1％时,能够制得流变性较佳的生物质水煤浆;搅拌强度的增加能够使生物质水煤浆的粘度降低;当温度低于60℃时生物质水煤浆的粘度随温度升高而下降;当温度高于60℃时,生物质水煤浆的粘度随温度升高而上升。     

Corrosion of Li-ion battery cathode materials on mullite insulation materials during calcination

A specially designed experimental device was used in laboratory to investigate the corrosion of mullite during the calcination of Li(Ni_xCo_yMn_z)O₂ (LNCM) materials. The anti-corrosion tests were carried out at 1000, 1100, 1200 and 1300 °C, and characterized with X-ray diffraction and scanning electron microscopy. The influence of temperature on the interactions between mullite insulation materials and LNCM materials was determined. In addition, the high-temperature creep properties of the mullite insulation materials before and after corrosion were tested. The laboratory scale tests, thermodynamic and kinetic calculations allowed a more comprehensive understanding of the evolution of the mullite insulation materials during serving for the roasting process of LNCM materials. Through this research, it is suggested that the upgrading of the kiln lining in the lithium battery industry should select materials with excellent resistance to alkali corrosion, especially excellent resistance to Li⁺ corrosion.