The surface carboxyl group of carbonaceous microspheres effects on the synthesis and structure of SiOC ceramics

In this study, C/SiOC and C/SiO₂ composites were prepared by using carbonaceous microspheres with different surface functional groups. Carbonaceous microspheres based on hydrothermal reaction of glucose contains hydroxyl group, while the surface carboxyl group increases after NaOH etching. The hydroxyl group increases the oxygen-enriched structural units of SiOC ceramics, and the C spheres are closely enwrapped in SiOC matrix after pyrolysis at 900 °C. However, the interfacial reaction of surface carboxyl with Si–OH results in the formation of cristobalite SiO₂, and C spheres are not only encased inside the SiOC matrix, but also dispersed outside of SiOC ceramics. After removal of C via calcination at 500 °C for 5 h, C/SiOC and C/SiO₂ composites are transformed into amorphous SiO₂ and cristobalite SiO₂, respectively. The thermogravimetric analysis indicates the oxidation resistance of SiOC is superior to that of C and SiO₂.     

影响PET树脂反应活性因素的分析

探讨了影响连续固相增粘产品活性的因素，提出了控制主反应器的温度、氮气流量、基础切片的端羧基、氮气露点等主要因素，实现生产的平稳控制，从而保证产品黏度的稳定。     

软段含羧基的水性聚氨酯贮存稳定性研究

合成了软段含羟基的水性聚氨酯（WPU），对影响其贮存稳定性的各种因素进行了研究，通过显微镜对PU进行了观察。结果表明：以甲苯二异氰酸酯（TDI）合成，在有性溶剂（如丁酮、丙酮）条件下用三乙胺中和，采用较小相地分子质量的聚酯有利于增强WPU的贮存稳定性，以TDI合成的PU-TDI体系的粒径较PU-IPDI体系的小，稳定性高；以丁酮、丙酮为溶剂的PU-IPDI体系相反转完全。     

氧化淀粉变性基团的分析方法

介绍了淀粉工业中氧化淀粉变性基团羧基和羰基的测定方法     

直纺长丝工艺中聚酯熔体端羧基值控制的工业研究

本文从工业生产的实践出发对杜邦聚酯技术直接纺工艺中端羧基控制进行了研究。通过对熔体端羧基值对无油长丝端羧基、粘度及纺丝加工影响的分析 ,阐明了聚酯端羧基控制范围 ;通过摸索三个反应釜工艺条件对端羧基值的影响 ,找出了端羧基工业控制的有效途径 ,为同类技术装置生产提供了依据     

羧基偏氯乙烯丁苯胶乳粒子的相态结构和应用性能

以过硫酸铵为引发剂，十二烷基硫酸钠为乳化剂，采用种子聚合工艺，合成了偏氯乙烯质量分数为２３％～４３％的羧基偏氯乙烯丁苯胶乳。通过电镜观察到所合成的胶乳粒子具有核－壳结构。通过测定胶闰子表面层的羧基数量，研究了羧基的分布，结果表明，羧酸种类对羧基在胶乳粒子中及在聚合体系中的分布有重要影响，该胶乳作为地毯背衬粘合剂，具有粘合力高，极限氧指数高的特点，是一种较好的阻燃性粘合剂。     

双氧水氧化橡实淀粉的实验研究

以双氧水为氧化剂,Cu2+为催化剂制备橡实氧化淀粉,考察pH值、氧化剂用量、催化剂用量、反应温度及反应时间对橡实氧化淀粉的羰基和羧基质量分数的影响.结果表明,最佳反应条件为:反应温度45℃,反应时间3 h,pH=8,H2O2用量为20%(相对于淀粉干重质量,下同),在此条件下,当催化剂用量为0.052 4%(相对于淀粉干重的质量)时,制得羧基质量分数为0.914 0%的橡实氧化淀粉;在催化剂用量为0.124 4%时,制得羰基质量分数为0.918 3%的橡实氧化淀粉.     

Aqueous solution of Oxone as new oxidizing agent for multi-walled carbon nanotube functionalization

In this work, multi-wall carbon nanotube (MWCNT) was successfully modified using aqueous solution of Oxone as a new oxidant. The effect of oxidation temperature on various characteristics of the treated MWCNTs was also investigated. FTIR and titration analysis proved the formation of carboxyl, carbonyl and epoxide groups at the surface of MWCNTs. The concentration of the functional groups increased as the modification temperature increased. The presence of such oxygen containing groups at the surface of MWCNTs justified the long time stability of the treated MWCNTs suspensions in water and methanol. The modified MWCNTs showed higher entanglement compared to row MWCNT due to the cross-links adjacent effect of pendant functional groups. Finally, it was concluded that Oxone oxidation process destroys the structure of the MWCNTs, but not severe enough to unzip the MWCNTs.     

溶液法合成端羧基聚丁二烯

以过氧化戊二酸为引发剂，无水乙醇或丙酮为溶剂，采用自由基型溶液法合成了端羧基聚丁二烯，并用ＩＲ对聚合物的微观结构进行了表征。结果表明当聚合反应温度为１０５￣１１５℃时，合理搭配引发剂起始用量和连续加入引发剂的递减速率，可合成满足不同应用领域的端羧基聚丁二烯产品。     

Effects of Genetically Engineered Stem Cells Expressing Cytosine Deaminase and Interferon-Beta or Carboxyl Esterase on the Growth of LNCaP Prostate Cancer Cells

The risk of prostate cancer has been increasing in men by degrees. To develop a new prostate cancer therapy, we used a stem cell-derived gene directed prodrug enzyme system using human neural stem cells (hNSCs) that have a tumor-tropic effect. These hNSCs were transduced with the therapeutic genes for bacterial cytosine deaminase (CD), alone or in combination with the one encoding human interferon-beta (IFN-β) or rabbit carboxyl esterase (CE) to generate HB1.F3.CD, HB1.F3.CD.IFN-β, and HB1.F3.CE cells, respectively. CD enzyme can convert the prodrug 5-fluorocytosine (5-FC) into the activated form 5-fluorouracil (5-FU). In addition, CE enzyme can convert the prodrug CPT-11 into a toxic agent, SN-38. In our study, the human stem cells were found to migrate toward LNCaP human prostate cancer cells rather than primary cells. This phenomenon may be due to interactions between chemoattractant ligands and receptors, such as VEGF/VEGFR2 and SCF/c-Kit, expressed as cancer and stem cells, respectively. The HB1.F3.CE, HB.F3.CD, or HB1.F3.CD.IFN-β cells significantly reduced the LNCaP cell viability in the presence of the prodrugs 5-FC or CPT-11. These results indicate that stem cells expressing therapeutic genes can be used to develop a new strategy for selectively treating human prostate cancer.