微胶囊红磷的制备及其在聚氨酯硬泡中的阻燃应用

以三聚氰胺甲醛为囊材,通过原位聚合法制备了三聚氰胺甲醛包覆的微胶囊红磷(MF-MRP),并以MF-MRP为阻燃剂,采用一步全水发泡法制备了含MF-MRP的聚氨酯硬泡(PURF)。利用DTA,FTIR,SEM等方法研究了MF-MRP的形态结构及其对PURF的阻燃效果。实验结果表明,由于红磷被三聚氰胺甲醛完全包覆,MF-MRP的着火点由247℃提高至430℃,热稳定性提高;当PURF中MF-MRP的含量从0增至8%(w)时,PURF的极限氧指数从21.0%升至29.5%;MF-MRP对PURF的阻燃以凝聚相阻燃为主,通过在PURF表面生成致密的炭层提高其阻燃性。     

水滑石/红磷协同阻燃EVA材料的热分解特性

采用熔融共混方法制备了EVA/水滑石(LDH)/微胶囊化红磷(MRP)无卤阻燃材料,研究了LDH和MRP在乙烯与醋酸乙烯共聚物(EVA)中的阻燃协同作用,发现在EVA/LDH阻燃体系中添加适量的MRP可以显著提高体系阻燃性能,而且燃烧过程中不再有熔滴现象发生。采用TG和实时傅立叶变换红外光谱(RT-FT-IR)研究了EVA及其复合阻燃材料的热分解特性,实验发现,与EVA/LDH体系相比,EVA/LDH//MRP体系的热稳定性有所提高,MRP对EVA/LDH体系中的EVA热氧化降解具有一定的抑制作用。     

大鼠胰岛细胞原代培养模型的研究

目的: 建立一种客观的用于糖尿病和降血糖药物研究的大鼠胰岛细胞原代培养模型。方法: 大鼠胰腺经胶原酶消化后,利用细胞贴壁时间、紧密程度及存活时间的差异,获得较为纯净的胰岛细胞。通过胰岛素含量测定,葡萄糖刺激实验及移植实验评价该细胞的功能。结果: 分离得到的胰岛细胞成活率可达95 %以上;双硫腙染色表明大部分细胞团为含有β细胞的胰岛细胞团;经RPMI 1640培养的细胞,其上清及细胞内的胰岛素含量均高于DMEM组,且对葡萄糖刺激的敏感性优于DMEM组;培养的胰岛细胞移植入1型糖尿病模型小鼠体内,可使糖尿病小鼠的血糖降至正常。结论: 利用该方法得到的胰岛细胞活力和纯度均较高,体外培养后细胞功能正常,有望成为一种实用的降糖药研究的细胞模型。     

Histomorphological and quantitative immunohistochemical changes in the rat pancreas during aging

Although the endocrine pancreas is the purpose of several deep investigations, morphological data referred to the effect of aging on the gland are not homogeneous. The purpose of the current work was to analyze the changes occurring in the pancreas of aged rats, with especial reference to the islet cell populations. Six young (Y), old (O) and senescent (S) male Sprague-Dawley rats were used. The pancreas tails were processed for light microscopy and studied by means of routine stains as well as by immunohistochemical identification of insulin-, glucagon-, somatostatin-, and pancreatic polypeptide- secreting cells (Dako Envision System, DAB as chromogen). A progressive pancreatic histoarchitecture distortion was found among the aged animals. Even when the alterations were not uniformly observed, they appeared more evident and severe in the S group. The S rats showed significantly increased volume density and cell density of the B cell population, as well as larger number of islet profiles, when compared to O rats. A significant progressive increment of adipose tissue was also evident in aged animals. No abnormal changes were detected in the nonB cell populations of the different groups.
The quantitative changes found in aged animals suggest a possible compensatory reaction of the B cell population in an attempt to curb the influence of diabetogenic factors mounting with advanced age.     

用于拼染的微胶囊化分散染料初选

选用工厂生产常用的C．I．分散红73、C．I．分散黄211和C.I.分散蓝183这3种纯分散染料进行微胶囊化并实施无助剂染色。通过改变微胶囊化时的芯壁比,控制分散染料缓释速率,并考察相应微胶囊化分散染料的高温高压染色上染曲线、初染率、匀染性及提升力等染色性能。最终找出微胶囊化芯壁比的变化与染色性能之间的关系,筛选出适于无助剂拼染的微胶囊化分散染料最佳组合。     

新型相变储能材料研究进展

介绍了相变材料的种类、特点以及储能机理,重点论述了新型相变材料的研究发展,对于复合相变材料和胶囊化相变材料做了较为详细的说明,概括了相变材料的主要研究方向.     

微胶囊相变材料研究进展

首先介绍了微胶囊相变材料及其组成,并就微胶囊相变材料的制备方法、性能改进、性能表征以及在能量利用和热交换领域、温度控制领域和军事领域上的应用进行了综述.     

Mg(OH)2-Al(OH)3-微胶囊红磷/高抗冲聚苯乙烯无卤阻燃复合材料

以氢氧化镁(MH)、氢氧化铝(ATH) 和微胶囊红磷(MRP) 为无卤阻燃剂, 高抗冲聚苯乙烯(HIPS) 树脂为聚合物基体, 通过熔融共混法制备了一系列不同组成的MH-ATH-MRP/HIPS复合材料。采用水平燃烧、垂直燃烧、氧指数、锥形量热分析、高温热分解实验等方法研究了复合材料的阻燃性能。结果表明, 阻燃剂用量相同时, 在HIPS基体中同时引入MH和ATH得到的复合材料比单独加入MH或ATH得到的复合材料具有更好的阻燃性能。当MH-ATH/HIPS的质量比为70:30:100时, 复合材料的水平燃烧级别达到FH-1级, 氧指数为25.2%, 但垂直燃烧无级别。在上述体系中加入极少量的MRP(占复合材料的质量分数为2.9%)就可使复合材料的火灾性能指数(FPI) 提高85%, 燃烧过程中热量释放和质量损失更慢、成炭能力明显增强, 垂直燃烧级别达到FV-0级。当MH-ATH-MRP/HIPS的质量比为21:9:12:100时, 复合材料的各项阻燃性能达到最佳, 可以大幅度减少阻燃剂的用量。MH、ATH和MRP对HIPS具有非常显著的协同阻燃作用。同时加入MH和ATH时不仅可以在更宽的温度范围内抑制HIPS的升温和分解, 而且能够在更宽的温度范围内相继释放出水蒸气稀释氧气和可燃气体的浓度, 从而起到协同阻燃作用。加入MRP后复合材料的成炭能力大大增强, 进一步改善了凝聚相阻燃的效果, 因此阻燃性能显著提高。     

Experimental measurements and numerical computation of nanofluid and microencapsulated phase change material in porous material

The electronic industry is increasingly investigating different approaches for the cooling of electronic equipment. The use of bulk phase change materials is also a promising approach for energy storage. The introduction of microencapsulated phase change materials combined with nanofluids can be beneficial. The combined use of a nanofluid and a metallic porous material can be used to mitigate problems resulting from small thermal conductivity. This study investigated a ternary mixture of water with a nanofluid and a microencapsulated phase change material in a porous medium. The model was previously validated with experimental data using a 0.5%vol concentration nanofluid in water. The results revealed that heat storage capability can be achieved as long as the microencapsulated phase change materials, which consists of encapsulated eicosane, is at a concentration of 20%. Because the melting temperature of microencapsulated phase change materials is approximately 36^°C , energy storage at a low flow rate and heat flux is recommended.     

Pancreatic Islets Accumulate Cadmium in a Rodent Model of Cadmium-Induced Hyperglycemia

Cadmium (Cd) is an anthropogenic as well as a naturally occurring toxicant associated with prediabetes and T2DM in humans and experimental models of Cd exposure. However, relatively few studies have examined the mechanism(s) of Cd-induced hyperglycemia. The purpose of this study was to examine the role of pancreatic islets in Cd-induced hyperglycemia. Male Sprague–Dawley rats were given daily subcutaneous doses of Cd at 0.6 mg/kg over 12 weeks. There was a resulting time-dependent increase in fasting blood glucose and altered insulin release in vitro. Islets isolated from control (saline-treated) and Cd-treated animals were incubated in low (0.5 mg/mL) or high (3 mg/mL) glucose conditions. Islets from 12 week Cd-treated animals had significantly less glucose-stimulated insulin release compared to islets from saline-treated control animals. The actual Cd content of isolated islets was 5 fold higher than the whole pancreas (endocrine + exocrine) and roughly 70% of that present in the renal cortex. Interestingly, islets isolated from Cd-treated animals and incubated in high glucose conditions contained significantly less Cd and zinc than those incubated in low glucose. These results show that within whole pancreatic tissue, Cd selectively accumulates in pancreatic islets and causes altered islet function that likely contributes to dysglycemia.