聚丙烯的结晶形态调控与高性能化

聚丙烯作为目前最重要的通用塑料之一,对其进行高质化改性具有重大的现实意义.基于聚丙烯的同质多晶态行为,加入成核剂进行β结晶改性是改善聚丙烯韧性和热稳定性的有效方式.过去的研究主要关注结晶度、β晶含量等对性能的影响.而近年来我们提出通过调控聚丙烯的β结晶形态来实现其高性能化的新思路,并开展了卓有成效的研究工作:(1)利用小分子成核剂的溶解性及自组装影响聚丙烯的结晶行为,获得了如球晶、横晶、花瓣状晶等形态,实现了对β结晶形态的有效调控;(2)特定的结晶形态能够使聚丙烯的韧性显著增加,并且热变形温度进一步提高,证实结晶形态会对宏观性能发挥重要作用;(3)β结晶形态调控有利于获得更佳的成孔均匀性与高的孔隙率,对制备高品质锂电池隔膜有明显的指导意义.结晶形态调控可望成为实现结晶性聚合物高性能化与功能化通行的、高效的策略.     

SUPER POLYOLEFIN BLENDS ACHIEVED VIA DYNAMIC PACKING INJECTION MOLDING:MORPHOLOGY AND PROPERTIES

As a long-term project aimed at developing super polyolefin blends, in this paper we summarize our work on themechanical reinforcement and phase morphology of polyolefin blends achieved by dynamic packing injection molding(DPIM). The main feature of this technology is that the specimen is forced to move repeatedly in the model by two pistonsthat move reversibly with the same frequency during cooling, which results in preferential orientation of the dispersed phaseas well as the matrix. The typical morphology of samples obtained via DPIM is a shear-induced morphology with a core inthe center, an oriented zone surrounding the core and a skin layer in the cross-section areas. Shear-induced phase dissolutionat a higher shear rate but phase separation at low shear rates is evident from AFM examination of LLDPE/PP (50/50) blends.The super polyolefin blends having high modulus (1.9-2.2 GPa), high tensile strength (100-120 MPa) and high impactstrength (6 times as that of pure HDPE) have been prepared by controlling the phase separation, molecular orientation andcrystal morphology.     

化学反应的内禀反应坐标法(Ⅶ)——乙炔与乙烯[2s+2a]环加成反应的反应路径解析

采用IRC在RHF/3-21G水平上对乙炔与乙烯的[2_s+2_a]加成反应途径进行了量子化学从头算.结果表明此反应是由乙烯和乙炔分子间的相向平动向产物的振动转化实现的.从理论上说明了反应物分子上的取代基对这一反应过程起促进作用.IRC解析直观地体现了此反应过程所遵守的轨道对称守恒规则.     

化学力显微镜对ω-巯基正十一胺自组装单分子膜的力滴定研究

采用化学力显微术（ＣＦＭ）研究了一种长链氨基自组装单分子膜的力滴定性质,考察了表面基团性质不同的力探针对力滴定的影响,滴定了金包覆的Ｓｉ３Ｎ经－ＯＨ和－ＮＨ２基功能化的金样品之间的粘滞力,得到了作为淀粉 ＰＨ值函数的粘滞力曲线（力滴定曲线）,结果表明,－ＮＨ２和－ＯＨ基功能化的表面ｐＫ１／２分别为８．４和９．０。     

EXTENDED SELF SIMILARITY OF PASSIVE SCALAR IN RAYLEIGH-BNARD CONVECTION FLOW BASED ON WAVELET TRANSFORM

Wavetet transform was used to analyze the scaling law of temperature data (passive scalar) in Rayleigh-Bénard convection flow from two aspects. The first one was to utilize the method of extended self similarity, presented first by Benzi et al., to study the scaling exponent of temperature data. The obtained results show that the inertial range is much wider than that one determined directly from the conventional structure function, and find the obtained scaling exponent agrees well with the one obtained from the temperature data in an experiment of wind tunnel. The second one was that, by extending the formula which was proposed by A. Arneodo et al. for extracting the scaling exponent ζ(q) of velocity data to temperature data, a newly defined formula which is also based on wavelet transform, and can determine the scaling exponent ξ(q) of temperature data was proposed. The obtained results demonstrate that by using the method which is named as WTMM (wavelet transform maximum modulus) ξ(q) correctly can be extracted.     

异自旋中心三自由基分子的磁性设计

采用量子化学DFT UB3LYP方法,在6-31G(d)基组水平上讨论了以1,3,5-苯为 铁磁耦合单元的异自旋中心三自由基体系。结果表明：对于异自旋三自由基体系, 形成异自旋后对称性降低使部分占据的近简并轨道能级劈裂值增大,反铁磁耦合作 用普遍增强。由两个同自旋和一个异自旋中心构成的三自由基若保持较好的对称性 (C_(2v))可望表现铁磁耦合。在通常情况下这类分子服从已有规律：ΔE_(POMO)小 ,ΔE_(D-Q)大,表现为稳定的四重态基态,且其稳定性与苯环2,4,6碳位置及自 由基原子上的自旋密度相关。     

分散聚合中溶剂回收利用的可行性

微米级单分散聚苯乙烯微球;分散聚合中溶剂回收利用的可行性     

剪切作用下马来酸酐接枝乙烯-辛烯共聚物和乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物对PA1010/PP共混物的增容作用比较

采用熔体共混的方法制备了两种增容剂增容的聚酰胺1010/聚丙烯(PA1010/PP)共混物,通过扫描电镜(SEM)、力学性能和差示扫描量热(DSC)测试,对动态保压注射成型(动态)和普通注射成型(静态)中增容剂POE-g-MAH(马来酸酐接枝乙烯-辛烯共聚物)和PTW(乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物)对PA1010/PP共混物的增容作用进行了比较研究.研究结果表明,普通注射成型中,PTW增容体系具有更小的分散相粒子,在DSC测试中出现两个结晶峰,即出现异相成核结晶和均相成核结晶,具有更好的拉伸和冲击性能,增容作用更佳.动态保压注射成型中施加剪切可以提高所有共混物的拉伸强度、拉伸模量和缺口冲击强度,PTW和POE-g-MAH两种增容剂增容体系冲击性能相近,但POE-g-MAH增容体系的分散相相区尺寸减小明显、分布均匀性显著增加,材料冲击强度增加幅度更大,表明剪切更有利于POE-g-MAH增容作用的进行.两种增容剂增容作用的不同源于它们化学组成的不同引起的材料形态差别.     

基于人眼视觉特性的LED照明技术

介绍了人眼的视觉特性和中间视觉的特点,提出通过选择合适的s／p值LED可提高中间视觉下LED照明的光效,并结合基于人眼视觉转换特性的动态调节技术和LED背光源照明技术,实现了真正意义的节能、舒适、人性化的LED照明。     

单层 FeO 薄膜表面周期性氧缺陷结构的形成

 采用扫描隧道显微镜和 X 射线光电子能谱对含有次表层 Fe 的 Pt 表皮结构 (Pt skin), 即 0.4 ML Fe 的 Pt/Fe/Pt(111) 表面, 在 1.1 × 10?7 kPa 氧气气氛退火过程中的变化进行了研究. 结果表明, 当退火温度为 600 K 时, 氧气在 Pt/Fe/Pt(111) 表面上解离吸附并诱导表面局域结构的重构; 750 K 时次表层 Fe 可以扩散到表面并被氧化; 当升至 850 K 时, 在样品表面形成单层 FeO 结构, 并且 FeO 表面具有周期性的缺陷. 这种缺陷是由于单层 FeO 薄膜的摩尔条纹单胞中 fcc 位上一个或多个氧原子缺失形成的, 其中多原子空位被确定为缺失 6 个氧原子所致. FeO 表面缺陷结构的研究为理解 Fe-Pt 催化剂在氧化气氛中的结构稳定性以及构造表面活性位提供一定的基础.