单体结构对紫外光固化氧阻聚影响的研究

利用光量热仪(UV-DSC)对单体TMPTA以及不同乙氧基化的TMPTA单体进行了紫外光固化实验。通过比较空气气氛和氮气气氛下光固化速率增长最快时的时间t_amax的差异来评价光固化初期氧阻聚的大小。考察了单体中乙氧基上的α-H的数量以及单体的流动特性对氧阻聚的影响。结果表明,提高单体中乙氧基的数量能减小光固化过程中的氧阻聚,氧阻聚的大小与单体中α-H的数量以及单体的黏度有关.     

甲基丙烯酸丁酯在纳米TiO2表面的原位接枝

利用分子自组装技术,对纳米TiO2粒子表面组装上有机单分子层,使其带上不饱和基团C=C,在自组装单分子层表面原位引发甲基丙烯酸丁酯（BMA）单体聚合反应,使纳米TiO2表面形成化学键合的聚合物层,达到对纳米TiO2粒子改性的目的。讨论了不同反应条件对接枝聚合率的影响,通过FTIR、TG-DTA等分析手段,研究聚合改性物质的结构和改性后纳米TiO2粒子的分散稳定性。实验发现聚合改性后的纳米TiO2在有机相中有良好的分散性。     

理想共聚体系共聚物组成方程的推导

理想共聚体系共聚物组成方程的推导彭宇行（中国科学院成都有机化学研究所，６１００４１）理想共聚是连锁聚合反应（自由基聚合、阳离子聚合和阴离子聚合）中的一类特殊共聚体系。在理想共聚中由不同单体生成的链增长活性中心对各共聚单体具有相同的反应活性，使得共聚物...     

γ-射线辐射活性自由基聚合研究

本文对γ- 射线辐射条件下的活性自由基聚合反应研究及进展进行了综述。虽然γ- 射线辐射引发聚合反应通常是不可控的,但在有机硫化物,如二硫代羧酸酯或三硫代碳酸酯存在下,则成功地实现了可控/活性自由基聚合。聚合过程中聚合物分子量随单体转化率线性增长,不但可控,且分布窄,也可以用于合成嵌段共聚物。有机硫化物对聚合反应控制起着关键性作用,硫化物的结构对于γ- 射线辐射活性自由基聚合行为的影响显著。γ- 射线辐射聚合的突出优点是可在室温或更低的温度下实施,且不需要加入引发剂。在环硫化合物存在下,获得了环形聚合物;而且使热和光敏感的叠氮类单体实现了活性聚合。     

高固相含量羟基磷灰石浆料的制备及凝胶浇注成型

为提高羟基磷灰石(HAP)浆料在水分散体系中的稳定性, 获得良好的固化性能, 采用二甲基丙烯酰胺(DMAA)作为单体, N,N’-亚甲基双丙稀酰胺(MBAM)作为交联剂, 偶氮二咪唑啉丙烷(AZIP)为引发剂, 研究了不同分散剂含量和不同固相含量HAP浆料的流变性. 使用自制的亚微米级粉体原料, 制备了固相含量高达55%(体积分数)的稳定浆料, 并成功实现了浇注成型. 获得相对密度高达57.5%的素坯, 其抗压强度、抗弯强度最高值分别达到(37.0±6.5)和(13.8±1.0) MPa. 经1250 ℃无压烧结2 h, HAP陶瓷具有优良的烧结性能, 相对密度为98.7%, 抗弯强度和弹性模量分别达到了(85.3±9.9) MPa 和(133.0±10.2) GPa.     

DLP型3D打印用巯烯光敏树脂的制备与性能研究

基于DLP(Digital light processing)的3D打印技术因具有成型速度快、分辨率高、可打印复杂形状等优点而备受关注,开发可用于DLP型3D打印且性能优异的光敏树脂已成为研究热点。巯烯光聚合遵循自由基逐步聚合机理,相对于传统的丙烯酸酯链式聚合,巯烯聚合反应速度快、聚合网络均一、固化收缩率低。本文制备了一系列可用于DLP型3D打印的巯烯光敏树脂,探究了巯基单体含量对光敏树脂光聚合动力学、热机械性能、拉伸性能、固化收缩率和打印精度的影响。结果表明,巯基单体的加入会显著提高体系双键转化率,增加聚合网络均一性和断裂伸长率,降低固化收缩率。     

一类高效复合型光引发剂的合成研究

硫鎓盐是一类有效的阳离子光引发剂,同时它在光解时也有自由基生成,实质上它是一种阳离子-自由基复合型光引发剂.硫鎓盐广泛地应用于涂料、油墨、电子工业、微细加工和快速成型等领域.它的出现使原本不能发生光聚合的单体,如环氧化合物发生光聚合反应,同时,它具有不受氧干扰,引发效率高、表面硬度高、深层收缩小,且可在光固化后用加热使固化反应更彻底等优点.     

苯并噁嗪中间体/蛭石插层纳米复合物热固化行为的研究

通过对双酚A型苯并嗪中间体 (BOZ A) 蛭石插层纳米复合物固化过程的分析表明长链烷基铵阳离子对BOZ A的热开环聚合反应没有表现出催化作用 ,也不影响纳米复合物的结构形态 .不同蛭石含量的插层纳米复合物 ,在形成不同纳米分散状态的纳米复合物的过程中 ,蛭石晶片对BOZ A的热开环聚合具有明显不同的阻碍作用 ,蛭石含量为 3%的插层纳米复合物 16 0℃的凝胶化时间较纯树脂延长约 7min ,活化能升高约8kJ mol,固化反应热焓降低约 14J g ,使得固化物的固化程度较纯树脂降低约 7%～ 10 % ,阻碍作用最大 ,其它含量的次之     

无机纳米粒子表面引发接枝聚合

无机纳米粒子表面引发聚合反应是无机纳米粒子—有机聚合物杂化复合材料制备的一种重要途径。分子自组装技术的发展使得各种类型的聚合反应都有转移至无机纳米粒子表面进行的可能。本文综述了表面引发聚合反应用于制备高键合密度的聚合物接技无机纳米粒子的研究进展。     

HPMA/OMMT和HPMA/CPMI/OMMT纳米复合材料的制备与表征

通过甲基丙烯酸羟丙酯(HPMA)单体与N-(4-羧基苯基)马来酰亚胺(CPMI)单体在有机蒙脱土(OMMT)中经原位插层自由基聚合反应制备了聚合物-无机纳米复合材料.OMMT由钠基蒙脱土通过十六烷基溴化铵插层处理制备.通过XRD和TEM对复合材料结构进行了表征,证实HPMA单体和HPMA/CPMI共单体在OMMT中原位插层共聚得到的复合材料均为剥离型纳米复合材料.OMMT含量为3 wt%的PolyHPMA/OMMT纳米复合材料起始分解温度为250℃,比相应的纯聚合物的热分解温度提高30℃.随着OMMT含量的增加,热分解温度进一步提高.但在测试温度范围内,PolyHPMA/OMMT纳米复合材料均没有出现明显的玻璃化转变温度.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。