聚羟基丁酸酯的等温与非等温结晶动力学

用差示扫描量热法(DSC)研究了聚羟基丁酸酯(PHB)的等温与非等温结晶动力学。采用Avrami方程分析了等温结晶动力学,Avrami指数n≈2,表明PHB以异相成核的二维平面晶体方式生长,等温结晶活化能为82.4 kJ/min。采用Jeziorny法和莫志深法分析了PHB的非等温结晶动力学,Avrami指数n≈3,表明PHB非等温结晶过程以异相成核的三维球晶方式生长。     

二氧化硅基质包埋硅纳米晶的微观结构和发光性能

利用离子注入和后续高温退火的方法制备了包埋在二氧化硅(Si02)基质中的硅纳米晶,研究了不同离子注入浓度试样的微观结构和发光性能,以及硅纳米晶的生长机理和发光机制.结果表明:较小的硅纳米晶(<5 nm)其生长机理符合Ostwald熟化机理,较大的纳米晶(>10 nm)则是由多个小纳米晶粒通过孪晶组合或融合而成的;离子注入浓度为8×1016cm-2的样品其发光强度是离子注入浓度为3×1017cm-2样品发光强度的5倍;硅纳米晶内部的微观结构缺陷(如孪晶和层错)对其荧光强度有很大的影响.     

HDPE/LDPE/SBS高耐应力开裂复合材料亚微相态-力学性能-流变性能的研究(Ⅰ)

HDPE易受环境的影响产生应力开裂,这限制了其在工业上的应用.本文通过HDPE与SBS,LDPE混合,制得一系列不同组分的高分子合金.分析了其球晶结构和拉伸力学性质并用扫描电镜观察断口形态,并与最终测得的耐环境应力开裂时间进行比较.结果表明,共混体系耐应力开裂性能比纯HDPE有很大提高,而且应力开裂性能与材料的强度和球晶形态密切相关,强度较大且球晶小而不规则者,其耐环境应力开裂性能较好.     

纳米聚苯乙烯微球用于膜分离性能评价的研究

采用30nm羧基修饰和100nm硫酸盐修饰的聚苯乙烯(PS)微球作为截留物质,考察其和多种不同材质、不同截留性能的超滤膜在常规截留实验中的测试结果,探索了纳米级聚苯乙烯微球作为截留标准物质的可行性.实验结果表明,两种PS微球在发射波长为498nm和541nm处的荧光强度与其浓度具有良好的线性关系,可准确进行定量分析,检出限为(93±16)μg/L.在截留实验中,PS微球对PVDF和PES两种材质的膜有一定的吸附作用;而对于PS、PVC、PAN 3种材质的膜没有吸附作用,截留效果良好.初步确认PS微球能够准确、简便地评价超滤膜的截留性能.     

高聚物的等温结晶

综述了高聚物等温结晶、球晶结构等方面的研究进展，依据熔体结晶过程中临界晶核的形成、球晶的生长和结晶／非晶组分间的相互扩散等因素讨论了高聚物温结晶动力学、形态以及分子量对球晶径向生长速率的影响。     

乙基纤维素液晶共混膜的结构与富氧性能

研究了乙基纤维素(EC)的二氯乙酸或冰乙酸溶液液晶结构及溶液浇铸EC/低分子液晶共混膜的结构与富氧性能。结果表明,EC的溶致液晶态呈现Maltese黑十字消光的球晶形态,而且球晶上带有同心圆环的规则指纹结构,有时也呈现无规指纹结构(胆甾液晶特征结构);电场的施加或低分子液晶含量的加大,可使氧气透过系数显著加大,而温度上升却使氧气透过系数和氧氮分离系数同时加大。     

高质量四脚状ZnO纳米结构的制备及其影响因素

采用汽相传输法制备高质量四脚状ZnO纳米结构(T-ZnO).以ZnO纳米晶为同质催 化剂,在锌源-衬底间添加蒸汽过滤器,研究过滤器和纳米晶对产物组成和形态的影响,以及 T-ZnO的结构特征.实验结果表明,T-ZnO为纤锌矿结构,分布均匀、尺寸一致,由四个柱 状纳米棒和一个球形核心组成.纳米棒直径约为60nm,沿<0001>晶向生长.过滤器的使用可 有效地去除产物中颗粒,而ZnO纳米晶的使用明显降低其尺寸,提高其均匀性.     

用PECVD技术低温低氢稀释快速生长纳米晶硅薄膜的研究

以SiCl4和H2为气源,用等离子体增强化学气相沉积技术,在300℃的低温下,研究不同的氢流量对纳米晶硅薄膜生长特性的影响.实验发现,氢对薄膜生长特性的影响有异于SiH4/H2,在一定功率下,薄膜的晶化率随氢流量的减小而增加;而薄膜的生长速率也强烈依赖于氢流量,随氢流量的减小而增大,与氢流量对薄膜晶化度的变化关系一致.通过调控氢流量,在低氢流量条件下获得了生长速率高达0.35nm/s,晶化度高达76%的晶化硅薄膜.     

超临界二氧化碳渗透成核剂至聚乳酸的分散及对基体性能的影响

通过超临界二氧化碳渗透的方法将成核剂分子输运到聚乳酸基体中,使其达到与传统挤出共混方法相比更为均匀、粒度更小的分散,从而进一步细化聚乳酸的球晶尺寸,改善其结晶行为。球晶尺寸的降低增加了球晶界面的结合强度,提高了聚乳酸的冲击强度。     

聚偏氟乙烯结晶过程的研究

通过流延法制备聚偏氟乙烯(PVDF)薄膜,用偏光显微镜观察PVDF球晶的生长过程.分析了结晶方式及降温速率对PVDF结晶过程中晶粒形态结构的影响.实验结果表明,选用等温快速降温的工艺更有利于得到结晶均匀性较好的PVDF薄膜.     

Biocompatibility and Biodegradation of novel PHB porous substrates with controlled multi-pore size by emulsion templates method

PHB porous substrates were prepared based on the mono-membrane fabricated by emulsion templates method. The key factors of the method affecting the pore size and porosity of the PHB porous substrates were studied. The surface of PHB porous substrates were investigated by scanning electron microscope (SEM), which showed the even pore size and regular arranged pore. The transect of the PHB porous substrates prepared using the templates method was good. Moreover, the effects of variation of surfactant content (P%) and water content (R) on the pore size and porosity of PHB films were discussed. Preliminary studies showed that when P% is less than 20%, the pore size made by emulsion templates ranged from 5 μm to 30 μm with the value of P increasing. As P% is up to 20%. It was interesting to see that the porous substrates had muti-pore size distribution, i.e., median pore sizes were about 5 μm and inside the wall of pore, there existed numerous micro-pores size can be controlled from 100 nm to 500 nm only by adjusting the parameter R of the microemulsion. The cell-compatibility was evaluated via Chinese Hamster Lung (CHL) fibroblast cultivation in vitro. The Cells were cultured on both the mono-pore size membrane prepared by emulsion templates and the multi-pore size membrane prepared by microemulsion templates. It can be seen that the cells cultured on multi-pore size membrane stretched their morphology and proliferated better than that of mono-pore size membrane. These results indicated that the multi-pore size membrane had better cell-compatibility and was more suitable for tissue engineering. The degradation experiment indicated that the degradation of PHB porous substrates were accelerated by enzyme in vitro and the porous configuration was favorable to its degradation.     

Measurement of profiles along a circle on two flat surfaces by use of a Fizeau interferometer with no standard

A method for measuring profiles along a circle on a flat surface with no standard is described. For the measurement, two unknown surfaces are placed almost parallel, and the distance between them is measured many times along a circle by rotation of one of the surfaces. Profiles of the two surfaces can be determined from the distance data. In this study the measuring method is explained: The space between two surfaces measured with a Fizeau interferometer. Four measuring experiments are carried out for determining the profile of a precision-grade half-mirror; in each experiment a different ordinary mirror with unknown profile is used as the second mirror. Profiles of the precise mirrors obtained by these experiments agree closely, with deviations of approximately 2 nm. A similar experiment with many concentric circles was carried out with a precise half-mirror and another precise mirror. Although the profiles of many concentric circles were independent of one another, the result shows that the high-frequency component of a whole plane can be estimated.     

壳聚糖/PHB复合缓释微包囊的制备与体外释药评价

用疏水性聚酯PHB外包覆壳聚糖-三聚磷酸钠-阿斯匹林药物缓释体(CPA)制备了壳聚糖/PHB复合缓释微包囊(CPAB),以克服CPA遇酸不稳定的释药特点.用傅立叶红外分光光度计、激光粒度仪、扫描电镜表征了CPAB的组成、粒径及表面形貌.结果显示,CPAB粒径在50～100nm和载药率18.5%时,表面有不均匀的空隙.体外释药评价证实CPAB能有效解决CPA在酸性下的不稳定性,具有长效缓释作用.     

用扫描电镜观察聚丙烯的球晶结构

用熔体结晶和溶液结晶两种方法获得聚丙烯的球晶样品,经过溶胀、化学刻蚀后用扫描电镜进行观察,获得了清晰的立体感强的球晶照片。由SEM照片可以看出,球晶结构相当完善,突出地显现出球晶生长的“骨骼”结构。     

基于划刻实验的单晶锗材料去除机理研究

采用Cube压头对单晶锗进行变载与恒载纳米划刻实验, 利用扫描电子显微镜和原子力显微镜对已加工表面进行观测, 根据表面形貌将划刻过程分为延性域、脆塑转变域及脆性域三种, 对各个阶段的表面成型及材料去除方式进行了研究。使用最小二乘法对不同阶段划刻力进行非线性拟合, 并利用相关系数检验拟合函数可靠性, 结果表明划刻力与划刻深度存在强相关性。同时分析了单晶锗的弹性回复率随划刻距离的变化趋势, 结果表明工件的弹性回复率将从纯弹性阶段的1逐步回落至0.76左右。基于脆塑转变临界载荷, 以裂纹萌生位置作为脆塑转变标志, 首次结合工件已加工表面弹性回复, 提出一种适用于计算单晶锗的脆塑转变临界深度模型, 其脆塑转变临界深度为489 nm。     

悬浮法制得PP-g-HEMA结晶性能的研究

由悬浮法制得聚丙烯接枝甲基丙烯酸β羟乙酯（ＨＥＭＡ），用示差扫描量热计（ＤＳＣ）、广角Ｘ射线衍射（ＷＡＸＤ）、结晶速率仪、偏光显微镜对接枝物的结晶性能进行了定性、定量表征，比较了接枝前后聚合物结晶形态的变化。     

官能化聚烯烃弹性体增韧PA1010体系Ⅱ.结晶行为的研究

用WAXD,偏光显微镜（PM）及DSC研究了聚烯烃弹性体乙烯－α烯烃共聚物（EOCP）对PA1010结晶行为的影响。WAXD结果显示纯弹性体（EOCP）和接枝弹性体（EOCP－g-MA)对PA1010的晶型均不产生影响。PM观察则表明共混体系中EOCP与PA1010的相互作用很弱,在PA1010结晶过程中,大部分EOCP被排除在球晶之外,而接枝EOCP与PA1010存在较强的相互作用,大量的EOCP－g-MA作为成核剂,使PA1010球晶向结晶化方向发展,而且随弹性体含量的增多而加强,DCS分析证实了接枝EOCP以异相成核剂的方式促进了PA1010的结晶,尤其是促进了PA1010的高温结晶。     

2m比长仪纳米级精度线间距测量系统的研究

介绍了2 m比长仪系统的组成,对其采用光电显微镜动态瞄准刻线和激光干涉测长原理进行了分析,研究了提高刻线瞄准精度和激光干涉测长精度的方法及利用现代电子技术实现刻线信号和干涉信号自动同步快速处理方法。自动信号处理系统基于FPGA现场可编程电路技术和计算机技术。通过对金属线纹尺测量的实验表明,依据JJG 331—1994激光干涉比长仪检定规程进行实验,2 m比长仪单次最佳刻线瞄准精度优于10 nm(1σ),对其测量的不确定度分析表明,对于测量高质量的高等别线纹尺,其测量不确定度U=（20+40 L）nm（k=2）。     

含PET热致液晶共聚酯的合成及表征

本实验采用熔融缩聚方法合成了含PET的热致液晶共聚酯。反应分两步进行 :对羧基苯甲酸 (PHB)乙酰化和PET/PHB共聚酯的制备。通过正交实验确定了PHB含量是影响PET/PHB共聚酯特性粘度的最显著因素 ,在此基础上详细讨论了PHB含量对共聚酯液晶性、相转变、流变性的影响。分析结果表明 :合成的PET/ 6 0PHB共聚酯具有典型的液晶性