纳米碳酸钙的制备及表征

研究了以氧化钙和二氧化碳为原料,化学法制备纳米碳酸钙的工艺条件、添加剂的影响及形态。结果表明:中间体氢氧化钙的初始浓度、二氧化碳的流量、反应温度、搅拌速度及添加剂等在控制制备纳米碳酸钙颗粒的形状和尺寸中均十分重要。透射电镜观察结果表明:通过控制反应及添加剂,可以得到尺寸规整的链锁形、纺锤形和球形纳米碳酸钙。表面能谱证实产品为高纯的碳酸钙。X射线衍射和电子衍射的结果进一步表明:所制纳米碳酸钙均属方解石型六方晶系,a0=0.498 9 nm,c0=1.706 2 nm;为多晶结构。     

Investigation of structure and mechanical properties of toughened poly(l‐lactide)/thermoplastic poly(ester urethane) blends

In this study, poly(l ‐lactide) (PLA) is melt‐blended with thermoplastic polyurethane (TPU) to modify the brittleness of PLA. An aliphatic ester‐based TPU was selected in order to have an ester sensitivity for degradation and an inherent biocompatibility. Using this compatible TPU, there was no need to apply problematic compatibilizers, so the main positive properties of PLA such as biocompatibility and degradability were not challenged. The detected microstructure of PLA/TPU blends showed that when the TPU content was lower than 25 wt %, the structure appeared as sea‐islands, but when the TPU content was increased, the morphology was converted to a cocontinuous microstructure. A higher interfacial surface area in the blend with 25 wt % TPU (PLA25) resulted in a higher toughness and abrasion resistance. The various analyses confirmed interactions and successful coupling of two phases and confirmed that melt‐blending of PLA with the aliphatic ester‐based TPU is a convenient, cost‐effective, and efficient method to conquer the brittleness of PLA. The prepared blends are general‐purpose plastics, but PLA25 showed an optimum mechanical strength, toughness, and biocompatibility suitable for a wide range of applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43104.     

CFD study of non-premixed swirling burners: Effect of turbulence models

This research investigates a numerical simulation of swirling turbulent non-premixed combustion. The effects on the combustion characteristics are examined with three turbulence models: namely as the Reynolds stress model, spectral turbulence analysis and Re-Normalization Group. In addition, the P-1 and discrete ordinate (DO) models are used to simulate the radiative heat transfer in this model. The governing equations associated with the required boundary conditions are solved using the numerical model. The accuracy of this model is validated with the published experimental data and the comparison elucidates that there is a reasonable agreement between the obtained values from this model and the corresponding experimental quantities. Among different models proposed in this research, the Reynolds stress model with the Probability Density Function (PDF) approach is more accurate (nearly up to 50%) than other turbulent models for a swirling flow field. Regarding the effect of radiative heat transfer model, it is observed that the discrete ordinate model is more precise than the P-1 model in anticipating the experimental behavior. This model is able to simulate the subcritical nature of the isothermal flow as well as the size and shape of the internal recirculation induced by the swirl due to combustion.     

GPC的浓度效应

本实验用东洋曹达 HLC-802A GPC 仪考察了几种窄分布聚苯乙烯样品和两种宽分布聚苯乙烯样品.结果表明:(1)在0.10～0.15g/100ml 浓度以下几乎没有浓度效应.(2)浓度再增加,淋洗体积随之增加。(3)分子量随浓度增加而降低,且峰加宽.(4)分子量大者,浓度效应显著.窄分布样品比宽分布样品明显.(5)流速大,浓度效应显著.     

新型阳离子（甲基丙烯酸季铵盐酯－苯乙烯）共聚物的研究──Ⅰ阳离子（甲基丙烯酸二甲氨基乙酯溴代正丁烷盐－苯乙烯）共聚物的合成与表征

甲基丙烯酸Ｎ，Ｎ－二甲氨乙酯（ＤＭＡＥＭＡ）与溴正丁烷在丙酮溶剂中进行季铵化反应，制得甲基丙烯酸季铵盐酯（ＭＢＤＭ）；然后以ＡＩＢＮ为引发刑，ＭＢＤＭ与苯乙烯（Ｓｔ）在溶液中进行自由基共聚，制得阳离子共聚物Ｐ（ＭＢＤＭ－Ｓｔ），其结构用红外光诸法鉴定，并经￣１ＨＮＭＲ和元素分析表征，证实有可能根据δ２．８～４．１和δ７．２２处两个共振峰确定共聚物的组成．     

中空玻璃微珠填充环氧树脂复合材料

讨论了用发电厂固体废料中的中空玻璃微珠填充Ｅ－４４环氧树脂制备轻质复合材料，实验详尽地考察了微珠填料，ＫＨ－５００偶联剂，固化剂（三乙基四胺，Ｔ－３１，三乙醇及液体四氢苯酐）及低聚酰胺等增韧剂等对所得的复合材料为力学性能的影响，并通过扫描电镜（ＳＥＭ）观察了材料的形态，其结果表明，偶联剂和增韧剂对复合材料的力学性能影响较大，中空玻璃微珠填充环氧树脂赋予基轻质，高强，价廉等特性。