丙烯酸酯改性水性聚氨酯乳液的合成及胶膜性能研究

以异佛尔酮二异氰酸酯（IPDI）、聚碳酸酯二醇（PCDL）、二羟甲基丙酸（DMPA）三乙胺（TEA）、甲基丙烯酸甲酯（MMA）、丙烯酸丁酯（BA）为原料,采用原位乳液聚合法制备水性聚氨酯-丙烯酸酯（WPUA）复合乳液。考察了聚氨酯（PU ）含量、m(MMA):m(BA)、初始-NCO与-OH物质的量之比等因素对WPUA复合乳液及其胶膜性能的影响。结果显示,当w(PU)质量分数为80%、初始n(-NCO):n(-OH)=6.0、w(DMPA)=5%、m(MMA):m(BA)=4:6时,所得WPUA乳液性能稳定,其胶膜吸水率降低至9.80%,相比较未改性的聚氨酯胶膜的吸水率24.75%,其吸水率降低了60.4%;改性胶膜的拉伸强度达到28.9MPa,是未改性聚氨酯胶膜的1.53倍,制备出了性能稳定、具有优异耐水性和物理机械性能的WPUA复合乳液。     

阳离子型催化剂催化ε-己内酯开环聚合反应的研究进展

聚己内酯(PCL)是一种无毒、可生物降解的多功能高分子材料,广泛应用于生活用品和医药化工等行业。目前PCL主要通过催化ε-己内酯开环聚合获得,阳离子催化剂由于具有催化活性高、无毒等特点,在PCL的合成中已得到广泛应用,成为ε-己内酯开环常用的催化剂之一。介绍了PCL的理化性质和合成方法,详细阐述了各类型阳离子催化剂催化ε-己内酯开环聚合的反应机理。着重介绍了近几年阳离子型催化剂在己内酯聚合中的应用发展,并展望了阳离子催化在PCL开环聚合反应中的发展方向。     

换热式转化炉下猪尾管裂纹原因分析及改造建议

对已使用3 a、材料为Incoloy 800H合金的505C制氢装置换热式转化炉下猪尾管裂纹进行了分析,通过无损探伤、现场测量、材料元素分析、工艺运行状况、结构应力等方面的分析讨论,论证了裂纹产生的原因是由操作温度、结构应力等多种因素造成的,并对改进该装置提出了建议。     

新己烯合成方法的改进

以叔丁醇为原料,首先与盐酸反应生成氯代叔丁烷,然后与乙烯反应得到氯代新己烷,最后经消除生成新己烯.本试验中氯代叔丁烷的合成由回流反应改为常温反应,收率达到90％以上.氯代叔丁烷与乙烯的加成反应中用自制的硅铝复合催化剂替代无水三氯化铝,催化剂用量减少50％,收率达到88％以上.新己烯合成中用氢氧化钠替代氢氧化钾,收率达到85％以上.改进后的工艺条件较温和,原料易得,具有一定的工业化应用价值.     

芳烃抽提扩产改造

对25万t/a芳烃抽提装置进行优化改造,主要通过更换及添加换热器、对抽提塔内件进行变更并使用新型填料,提高芳烃抽提装置生产加工能力,使装置产能提高40%~50%。     

高密度块状钐铁氮磁体制备的研究进展

钐铁氮化合物(Sm₂Fe₁₇N₃)因具有比钕铁硼(Nd₂Fe₁₄B)更高的磁晶各向异性场和居里温度值及更少的稀土含量,成为新型稀土永磁材料研究热点。但是,由于钐铁氮在600℃左右会分解导致永磁性能消失,因此常规的高温烧结工艺并不适用于钐铁氮烧结磁体的制备,现只能将其与高分子材料复合用作塑磁材料,这就导致Sm₂Fe₁₇N₃的磁学性能无法得到充分发挥。因此,开发低温成型工艺制备全金属高密度块状磁体是获取高性能钐铁氮磁体的关键。经过30多年的努力,科研人员已开发出多种制备钐铁氮磁体的低温快速成型工艺,并获得最大磁能积达到199 k J/m³的高性能磁体。本研究将从磁体的制备方法出发,总结当前块状钐铁氮磁体的研究现状及面临的问题,尤其针对不同成型方法出现矫顽力下降的现象提出分析,并对其今后的发展做出展望。     

Synthesis of Chiral Cyclopropyl Carbocyclic Purine Nucleosides via Asymmetric Intramolecular Cyclopropanations Catalyzed by a Chiral Ruthenium(II) Complex

The synthesis of chiral cyclopropyl carbocyclic purine nucleoside analogues via the highly enantioselective intramolecular cyclopropanation reactions has been reported. With a chiral ruthenium(II)‐phenyloxazoline complex as the catalyst, cyclopropyl carbocyclic purine nucleoside analogues containing three contiguous stereocenters were obtained with up to 99% yield and 99% ee. Furthermore, a chiral cyclopropyl carbocyclic adenosine nucleoside having anti‐BLV activity could be synthesized in a concise manner using this strategy.

     

Astragalus membranaceus Inhibits Peritoneal Fibrosis via Monocyte Chemoattractant Protein (MCP)-1 and the Transforming Growth Factor-β1 (TGF-β1) Pathway in Rats Submitted to Peritoneal Dialysis

Inflammation and transforming growth factor-β1 (TGF-β1) contribute to the development of peritoneal fibrosis (PF), which is associated with peritoneal dialysis (PD). Astragalus membranaceus (Astragalus) has anti-inflammatory and anti-fibrotic effects in many diseases. The goal of this study was to determine the anti-fibrotic effects of Astragalus on the PF response to PD. A rat model of PD was induced using standard PD fluid, and PF was verified by HE and Masson’s staining, as well as through the expression of fibroblast surface protein (FSP) and collagen III. The expression levels of monocyte chemoattractant protein (MCP)-1, F4/80 (macrophage/monocyte marker in rat), TGF-β1 and the downstream proteins phospho-SMAD 2/3 in dialyzed peritoneal tissue treated with or without Astragalus was evaluated using immunohistochemistry analysis. Overall correlations between MCP-1 and TGF-β1 staining were analyzed using both the Spearman and Pearson methods. The results showed that Astragalus could inhibit the recruitment and activation of monocytes/macrophages, thereby reducing the production of TGF-β1 in the dialyzed peritoneal membrane. PF was also significantly decreased following treatment with Astragalus. MCP-1 expression had a strong positive correlation with TGF-β1 sensitivity, suggesting that the anti-fibrotic function of Astragalus was mediated by MCP-1 and the TGF-β1 pathway. Our results indicate that Astragalus could be a useful agent against PD-induced PF.     

弯管顺序输送影响因素研究

相邻批次的油品在进行成品油顺序输送时会产生一定量的混油。通过CFD软件,针对弯管顺序输送的条件下通过改变流速、粘度和弯径比来进行研究比较。结果表明,流速越小混油油头越尖锐,并且流速越大混油油头越靠近管道弯曲处;而后行油品粘度较大的比粘度较小的混油油头的位置相对滞后;弯径比较大的管道混油流经下游管段时混油段长度越长。其结果与工程现象基本吻合。为实际生产提供了一定的理论参考。     

Cu~(2+)、Zn~(2+)和Pb~(2+)对绿原酸与牛血清白蛋白结合作用的影响

以杜仲绿原酸(CA)为原料,在模拟人体生理条件下,采用荧光光谱和紫外吸收光谱等方法,考察Cu2+、Zn2+和Pb2+对CA与牛血清白蛋白(BSA)相互作用产生的影响。结果表明,金属离子的存在不会改变CA对BSA的猝灭类型,但对其猝灭速率常数(kq)、结合常数(K)以及结合位点(n)会有不同程度的影响;CA与BSA之间的反应属于自发型,主要以范德华力和氢键为主,Zn2+和Pb2+的存在不会改变其作用力类型,Cu2+则会使作用力变为以静电吸引力为主;Zn2+和Pb2+会将供体与受体之间的结合距离分别减小1.975%和14.07%,Cu2+的干扰使CA与BSA之间的结合距离增大11.58%;同步荧光光谱显示CA与BSA中的酪氨酸残基和色氨酸残基都有相互作用,三维荧光测定结果进一步表明猝灭剂对BSA构象及微环境会引起变化。