三聚氰胺-甲醛树脂包裹环氧树脂微胶囊的制备及表征

针对环氧树脂基材料的自修复,选取四氢邻苯二甲酸二缩水甘油酯作为芯材,采用三聚氰胺-甲醛树脂为壁材,对其进行微胶囊化包裹.结果表明,制得的具有单囊结构的环氧树脂微胶囊,胶囊粒径较小(约6.7μm)、囊壁较薄(约0.2μm)、芯含量较高(83.2 wt%),囊壁内、外表面光滑致密,胶囊具有良好的密闭性和耐热性;在微胶囊化过程中,三聚氰胺-甲醛树脂的缩聚反应动力学起关键作用,芯材没有参与囊壁形成的交联反应;包裹后的芯材活性保持不变,胶囊被复合到材料过程中囊芯活性也保持不变;胶囊的强度较高,能承受与基体材料复合过程中的外力作用,且与基体材料间粘结良好,在裂纹形成过程中能够随基体同时开裂.     

基于聚苯胺微胶囊的双重自修复防腐涂层

将乳液模板法、光聚合法以及苯胺的界面聚合相结合制备了负载亚麻籽油的聚苯胺微胶囊,并将微胶囊与水性环氧树脂涂层相结合来构筑了具有优异光热转化能力的双重自修复防腐涂层.当涂层受损后,微胶囊中的自修复剂亚麻籽油释放出来,对涂层进行修复;在近红外光(NIR)的照射下,聚苯胺可以有效地吸收光能并将其转化为热能,使涂层的温度高于其玻璃化转变温度,涂层破损处实现愈合.聚苯胺微胶囊的加入不仅赋予涂层优异的自修复能力,而且大大增强了其防腐能力.涂层的表面形貌、电化学与盐雾测试结果表明,聚苯胺微胶囊添加量为10%的涂层在NIR照射3 s内,可以实现快速闭合,恢复了其阻隔性能.此外,在300 h的盐雾测试后,涂层未产生任何的腐蚀产物,而纯涂层可以明显看到腐蚀现象.这种双重自修复防腐涂层的超快响应时间和高愈合效率以及优异的防腐性能具有潜在的应用价值.     

杂环化合物氢交换的核磁共振研究

芳香族化合物在酸的作用下可发生可逆的氢交换。该过程是质子对芳香环作亲电进攻,生成过渡态的芳烃离子,后者再失去氢离子完成了氢的化学交换,因而本质是亲电取代反应。例如某些简单的芳香族化合物用重水     

微胶囊碳酸氢钠合成工艺及热分解特性的研究

利用环氧树脂(EP)对碳酸氢钠(SB)进行包覆合成微胶囊碳酸氢钠,通过红外光谱仪(FTIR)、扫描电子显微镜(SEM)、差示扫描量热计(DSC)和热重分析仪(TG)等表征手段,分析了合成反应温度、环氧树脂与碳酸氢钠的质量比对微胶囊碳酸氢钠的结构、表面形貌特征以及热分解特性的影响.结果表明:当反应温度为70℃,环氧树脂与...     

pH值对正十八烷微胶囊合成与性能的影响

pH值对正十八烷微胶囊合成与性能的影响;微胶囊;相变材料;正十八烷     

含典型氟-氢邻近与远程耦合的混合物的核磁共振氢谱示例

Two serials of tetrasubstituted benzene compounds containing fluoro group were designed and synthesized. The other three substitutes are sequentially the para, meta, and ortho to fluoro group. The obtained compounds were all mixtures as confirmed by ¹H NMR spectroscopies. The spectra clearly show the proximity and remote interaction between fluorine atom and hydrogen atom. In addition, the two spectra, one showing the overlapping peaks, one not, can be used as the simple and typical example of ¹H NMR spectra of mixtures.     

叠氮二乙基铝三聚体和单体的缔合-解离平衡的研究

尽管叠氮二乙基铝Et₂AlN₃(DEAA)是一个重要的化合物,但人们对它研究还是很少的。本文通过温度-蒸气压关系研究了纯态DEAA的三聚体和单量体之间的缔合-解离平衡;通过相对分子质量测定、核磁共振氢谱和核磁共振铝谱的测定,研究了在苯和甲苯溶液中DEAA的三聚体和单量体之间的缔合-解离平衡。借助温度-蒸气压曲线分别计算了DEAA三聚体和单量体的气化焓和解离焓;通过相对分子质量测定、核磁共振铝谱测定等方法计算得到了溶液中DEAA三聚体和单量体的解离平衡常数、解离焓和解离熵等热力学数据。     

紫外光固化自修复剂的微胶囊化及智能防腐蚀涂层的制备

利用在水相中原位生成的聚脲甲醛沉淀吸附在可见紫外光固化组份构成的油相表面,制备了包覆自修复剂的脲醛树脂（PUF）微胶囊. 光学显微镜及SEM表明,PUF微胶囊尺寸为118-663 μm,与PUF 形成过程中的搅拌速度有关. 在中等搅拌速度（600 r/min）时,可以得到最高的包覆率（97.52wt%）和产率（65.23wt%）. 将此微胶囊掺入水性聚氨酯乳胶中制成的涂层表面受损后,在紫外光照射下可以进行自修复,具有优异的金属防腐蚀性能.     

海藻酸钙-壳聚糖微胶囊组成对BSA通透性能影响的研究

对海藻酸钙-壳聚糖微胶囊的牛血清白蛋白(BSA)双向通透性能进行了定量和定性的初步研究, 并初步考察了微胶囊的组成成分及海藻酸钠、壳聚糖的溶液浓度对BSA通透性能的影响. 结果表明海藻酸钙-壳聚糖微胶囊在pH 1.5～2.0时通透性减弱, pH 6.8时通透性增强, 且海藻酸钙微胶囊通透性大于海藻酸钙-壳聚糖微胶囊; 海藻酸钙-壳聚糖微胶囊中壳聚糖浓度越小, 通透性越好; 海藻酸钠浓度的影响不显著.     

2-芳基硫杂脯氨酸结构特征的研究

对12种2-芳基硫杂脯氨酸进行了红外光谱和核磁共振谱测定,对其中两个化合物作了质谱测定。结果表明,这类化合物固态时主要以两性离子形式存在;有较强的分子离子峰,是一类较稳定的化合物。它们还存在一对非对映异构体,芳环上的取代基对芳环电子云密度的影响较大,而对四氢噻唑环的影响较小。     

生物农药微胶囊壁材料研究

用原位聚合法对生物农药阿维菌素进行包囊,然后制备微胶囊制剂,并对用于该制剂的两种高分子囊壁材料-三聚氰胺甲醛树脂和脲醛树脂的性能进行了研究。结果表明,两种树脂皆为较好的生物农药用微胶囊缓释剂型的囊壁材料,其制备工艺简单,具有良好的稳定性、粒径大小与分布、悬浮性、缓释性等,包封率均达80％以上。其中三聚氰胺甲醛树脂悬浮性较脲醛树脂更好,缓释性更持久。     

不同条件下合成的纳米羟基磷灰石晶体的性能研究

用磷酸钠和硝酸钙为原料,在8种不同条件下制备了纳米羟基磷灰石(n-HA)晶体,研究了不同条件下制备的n-HA晶体的形态、组成、Ca/P摩尔比和结晶度。运用透射电镜((TEM)、红外光谱(IR)和X射线衍射(XRD)分析和表征了不同条件下得到的纳米羟基磷石灰晶体的形貌、组成和结晶度。用化学方法分析了纳米羟基磷灰石晶体的Ca/P摩尔比。结果表明,不同条件下合成的纳米磷灰石晶体均为含有HPO42-和CO32-的弱结晶结构,与自然骨磷灰石类似。     

Demonstration of methylene-ether bridge formation in melamine-formaldehyde resins

¹H and ¹³C NMR have been used for the quantitative determination of methylene-ether bridges in melamine-formaldehyde (MF) resins. The amount of methylene-ether bridges was determined by ¹³C NMR from the number of monomethylolated amino groups consumed in the condensation reactions and is in agreement with that calculated from the condensation water contents. This latter method, which involves a combination of ¹H and ¹³C NMR, is based on the amount of condensation water released during the formation of both methylene and methylene-ether bridges. © 1995 John Wiley & Sons, Inc.     

pH值对丝素蛋白构象转变的影响

模仿家蚕吐丝过程中伴随丝素蛋白自然脱水的纤维化过程,研究了再生丝素蛋白在各种pH值的磷酸盐缓冲溶液体系中自然干燥脱水成膜后的构象转变.利用激光拉曼散射光谱及其二维相关光谱,定性分析了丝素蛋白酰胺区(1600～1700cm^-1)散射峰的相关组成及结构.在此基础上,利用¹³CCP-MAS固体核磁共振谱对丝素蛋白丙氨酸C_β峰(δ14.5～22)进行了解析拟合.从而确定了体系中与Silk及Silk构象相关的组成含量与pH值的关系.结果表明,pH=5.2的酸性溶液有利于蚕丝丝素蛋白从Silk向Silk构象转变,而中性与碱性溶液(pH=6.9和8.0)则对丝素蛋白的构象转变影响甚小.     

Quantitative 1H NMR spectroscopic determination of the E/Z isomer ratio of the antidepressant drug fluvoxamine for use in pharmaceutical analysis

High‐resolution NMR spectroscopy is a powerful tool in the elucidation of a structure with respect to constitution, configuration and conformation. In recent years, NMR has been increasingly used in quantitative analysis. In this study, we show the ability of ¹H NMR to determine the isomeric composition of the antidepressant drug fluvoxamine. The activity of fluvoxamine resides on the E‐isomer, and the current British Pharmacopoeia limits the content of the Z‐isomer to 0.5%. The NMR method described here is able to determine the content of the Z‐isomer down to the 0.2% level on a total amount of 15 mg of the substance. Copyright © 2002 John Wiley & Sons, Ltd.     

从核磁共振氢谱推导的重质油氢碳原子摩尔比计算式

通过对炼油厂的催化油浆、重催油浆和催化重焦蜡油核磁共振氢谱中质子归属和重质油结构的假设，推导出计算这3种重质油的氢碳原子摩尔比计算式；结果表明，氢碳原子摩尔比的计算值与实测值非常接近，平均误差仅为3．1％。     

Investigation of the proton mobility in CsH(SO4)0.76(SeO4)0.24 crystal by H NMR spectroscopy

Crystals of CsH(SO₄)_0.76(SeO₄)_0.24 formulation were studied by ¹H NMR spectroscopy. The ¹H line-shape, the T₁ and T₂ relaxation times were determined as a function of temperature. The activation energies deduced from the temperature dependence of relaxation times were compared with the activation energy issued from conductivity measurements. The results obtained are discussed and supported by the Ngai model.     

Urea method for the synthesis of hydrotalcites

Mg-Al, Zn-Al and Ni-Al hydrotalcite-like compounds with high crystallinity were synthesized by using the decomposing property of urea at high temperature. The crystallinity and the regularly of the samples were much preferable to those synthesized by other methods. This revised version was published online in June 2006 with corrections to the Cover Date.     

A 13C NMR study of the methylol derivatives of 2,4′‐ and 4,4′‐dihydroxydiphenylmethanes found in resol phenol–formaldehyde resins

A total of 13 of the 16 possible methylol derivatives of 2,4′‐ and 4,4′‐dihydroxydiphenylmethane have been synthesized, isolated, and identified. These compounds are found as intermediates in the cure process of resol phenol–formaldehyde (PF) resins. Analysis of the ¹³C NMR spectra (in acetone‐d₆) of these compounds provided a way to evaluate the seven methylolphenol ring types (methylol derivatives of 2‐hydroxyphenyl and 4‐hydroxyphenyl rings) found in typical resol PF resins using the ipso carbon region from 150 to 160 ppm. A simple diagnostic test was developed using the chemical shift values of the methylol methylene carbon atoms to identify the presence of intermediates containing either a 2‐hydroxyphenyl or a 4‐hydroxyphenyl ring. Using these data it is now possible to analyze the major components in extracted prepreg PF resins. Copyright © 2002 John Wiley & Sons, Ltd.     

七、八元瓜环对萘二胺异构体相互作用的考察

利用紫外吸收光谱、荧光光谱以及¹H NMR方法考察了七、八元瓜环(Q[7], Q[8])与1,8-萘二胺(g1), 2,3-萘二胺(g2), 1,5-萘二胺(g3)的相互作用. 实验结果表明: Q[7]与客体g1发生端口作用, 作用比为1∶1; Q[7]与客体g2, g3相互作用也形成1∶1的包结配合物. Q[8]与三种客体相互作用情况各不相同, 除Q[8]与客体g2相互作用形成1∶2的包结配合物; Q[8]与客体g1或g3可发生相互作用, 形成溶解性较差的作用产物, 其表观相互作用的比例为1∶1. 考察溶液酸度对主客体相互作用的影响还表明: 当pH大于某一值之后, 如Q[7]主客体体系, pH大于6.0; Q[8]主客体体系, pH大于12.0, 用光谱方法观察不到瓜环与客体的相互作用. Q[7], Q[8]为主体的上述主客体作用产物分别与金刚烷胺盐酸盐、1,10-癸二胺盐酸盐的竞争反应结果表明, 已作用的萘二胺异构体容易被所选用的竞争客体所取代, 只有g2与Q[8]形成的包结配合物被1,10-癸二胺盐酸盐部分取代.