下二门油田有机铬/聚合物微凝胶体系研究

微凝胶驱油技术是解决目前聚合物驱中聚合物用量高、耐温抗盐性差、污水配制困难的新技术。文中结合下二门油田地质特点,开发状况,研究了有机铬/聚合物微凝胶驱油体系对下二门油田的适应性及影响因素;并在此基础上推荐了400mg/L聚合物+60mg/L交联剂的最佳配方。该配方成胶后粘度高于用下二门油田污水配制的1000mg/L聚合物溶液粘度。该技术驱油可降低成本,解决污水配制粘度低问题。最佳配方双管岩心驱油试验表明微凝胶驱可比水驱提高采收率18%～21%,具有很好的矿场应用前景。     

Fast and Ample Light Controlled Actuation of Monodisperse All-DNA Microgels

The assembly of adaptive hierarchical soft materials that resemble living tissues requires responsive building blocks of controlled dimensions. While DNA self-assembly provides an exceptional tool for nanoscale architectural control, responsive DNA microstructures remain scarce. Here, two challenges controlling the size of DNA microstructures and embedding them with fast and ample structural response are addressed. For size-control, arrested phase separation and microfluidic confinement are combined to produce monodisperse all-DNA particles. For responsiveness, a light controlled coil-globule transition of the microgel DNA network powered by an azobenzene cationic surfactant is implemented. The photoinduced trans-cis isomerization of the azobenzene moiety reduces its affinity for DNA which results in fast, large amplitudes microgel swelling. Finally, the assembly of light responsive microgel superstructures is demonstrated as proof-of-concept hierarchical all-DNA materials.     

Smoothing temperature and ratio of casein to whey protein: Two tools to improve nonfat stirred yogurt properties

Consumers are not always ready to compromise on the loss of texture and increased syneresis that nonfat stirred yogurts display compared with yogurts that contain fat. In this study, we investigated milk protein composition and smoothing temperature as a means to control nonfat yogurt microstructure, textural properties, and syneresis. Yogurts were prepared with different ratios of casein to whey protein (R1.5, R2.8, and R3.9). Yogurts were pumped through a smoothing pilot system comprising a plate heat exchanger set at 15, 20, or 25°C and then stored at 4°C until analysis (d 1, 9, and 23). Yogurt particle size and firmness were measured. Yogurt syneresis and water mobility were determined, respectively, by centrifugation and time domain low-frequency proton nuclear magnetic resonance (¹H-LF-NMR). Increasing the smoothing temperature increased gel firmness and microgel (dense protein aggregates) sizes independently of the whey protein content. Also, yogurt microgel sizes changed with storage time, but the evolution pattern depended on protein ratio. Yogurt R1.5 showed the largest particles, and their sizes increased with storage, whereas R2.8 and R3.9 had smaller microgels, and R3.9 did not show any increase in microgel size during storage. Micrographs showed a heterogeneous gel with the empty area occupied by serum for R1.5, whereas R2.8 and R3.9 showed fewer serum zones and a more disrupted gel embedding microgels. Induced syneresis reduced with greater whey protein content and time of storage. This is in agreement with ¹H-LF-NMR showing less bulk water mobility with increasing whey protein content during storage. However, ¹H-LF-RMN revealed higher values of spontaneous serum separation during storage for R1.5 and R3.9 yogurts, whereas these were lower and stable for R2.8 yogurt. Microgels play an important structural role in yogurt textural attributes, and their characteristics are modulated by whey protein content and smoothing temperature. Optimization of these parameters may help improve nonfat stirred dairy gel.     

多相泡沫体系深部调剖实验研究

作为一种新型深部调剖剂,凝胶微球与泡沫复合体系(多相泡沫体系)结合了凝胶微球深部调剖和泡沫封堵能力强的特点。从凝胶微球与泡沫的复配性入手,研究了凝胶微球和泡沫的注入特征,并对比了泡沫、凝胶微球和多相泡沫体系对非均质岩心的提高采收率情况。通过实验发现,在空气中,凝胶微球质量浓度为5g/L时,多相泡沫体系的稳定性最好;多相泡沫体系注入过程中压差呈"阶梯式"上升趋势,凝胶微球除了吸附在岩石孔隙表面,还可以在较小孔喉处通过架桥作用形成封堵。多相泡沫体系注入过程中产生了较强的压力波动,有利于采收率的提高。多相泡沫体系提高采收率效果要好于单独使用泡沫或凝胶微球,经过多相泡沫体系调剖后,低渗透岩心最终采收率要高于高渗透岩心最终采收率。     

Composite aqueous microgels: an overview of recent advances in synthesis,characterization and application

In the last decade there has been a steady increase in the number of publications describing the synthesis, characterization and applications of hybrid particles. Colloidal aqueous microgels form an important subdivision of polymer colloids used for the deposition of different functional materials. Due to their numerous attractive properties, microgel particles have been used as templates for the synthesis, storage and transportation of nanostructured materials. This paper reviews the important developments in the area of composite microgels over the last decade, and is limited to microgel particles operating in aqueous media. The patent literature is not included in the review. Different synthetic approaches as well as some properties and applications of composite microgels are discussed. Copyright © 2006 Society of Chemical Industry     

Ultrasound-triggered noninvasive regulation of blood glucose levels using microgels integrated with insulin nanocapsules

Diabetes is a serious public health problem affecting 422 million people worldwide.Traditional diabetes management often requires multiple daily insulin injections,associated with pain and inadequate glycemia control.Herein,we have developed an ultrasound-triggered insulin delivery system capable of pulsatile insulin release that can provide both long-term sustained and fast on-demand responses.In this system,insulin-loaded poly(lactic-co-glycolic acid) (PLGA) nanocapsules are encapsulated within chitosan microgels.The encapsulated insulin in nanocapsules can passively diffuse from the nanoparticle but remain restricted within the microgel.Upon ultrasound treatment,the stored insulin in microgels can be rapidly released to regulate blood glucose levels.In a chemically-induced type 1 diabetic mouse model,we demonstrated that this system,when activated by 30 s ultrasound administration,could effectively achieve glycemic control for up to one week in a noninvasive,localized,and pulsatile manner.     

含钐稀土-高分子荧光材料的制备和表征

合成了聚N-异丙基丙烯酰胺-丙烯酸P(NIPAM-co-AAc)共聚微凝胶与Sm(Ⅲ)离子、α-噻吩甲酰三氟丙酮（HTTA)的三元配合物。用激光光散射、Zeta电位、紫外光谱、红外光谱、荧光光谱进行了表征。结果表明．微凝胶粒径为360nm；Sm(Ⅲ)与微凝胶、HTTA之间以配位作用为主；微凝胶、HTTA和Sm(Ⅲ)之间能进行有效的能量传递。配合物的最佳激发波长为348nm，在此激发波长下Sm(Ⅲ)有荧光特征发射。     

具有右旋糖酐微结构的聚乙烯醇凝胶敷料的制备与性能

采用微波协助冻融法制备了包埋苯妥英钠的具有葡聚糖微结构的聚乙烯醇凝胶（Dex/PVA BHMs）敷料。结果表明,Dex/PVA BHMs凝胶的溶胀率和拉伸强度分别为19.3%和1.05MPa,溶胀率比传统聚乙烯醇（PVA）凝胶的提高了近2.5倍,但拉伸强度变化较小,使其获得了良好的稀释膨胀性能且保留了PVA凝胶高力学强...     

两相催化脱硫的PMAA／Fenton复合微球的构筑

以反相悬浮聚合法合成的PMAA微凝胶为模板,将Fe^2＋用浸渍法引入到PMAA模板且经过氧化氢溶胀后,以二苯并噻吩（DBT）为模型反应物,将其溶解于十氢萘中配成模型油。针对模型体系,初步考察PMAA／Fenton复合微球对模型油氧化脱硫的影响,利用扫描电子显微镜（SEM）和傅立叶变换红外光谱（FT—IR）对脱硫前后微球的形貌、组份进行分析。同时,利用气相色谱仪（GC—FID）对微球的脱硫效率进行表征,研究结果表明,PMAA／Fenton复合微球用于脱硫的最大特点在于催化剂负载于微凝胶上可实现循环使用、DBT的氧化产物不需萃取。