Synthesis and characterization of near monodisperse oligomeric polystyrenes

Oligomeric (<10³) polystyrenes have been synthesized on a practical scale by the use of secbutyllithium and triethylamine in cyclohexane. These samples were found to possess relatively narrow molecular weight distributions. The product analysis was accomplished by viscosity, vapour pressure osmometry, gel permeation chromatography and gas chromatography.     

N-月桂酰基乙二胺二乙酸钠的合成及性能研究

以月桂酸和乙二胺为原料,合成了中间体N-月桂酰基乙二胺(LED),进一步与氯乙酸钠反应,得到目标产物N-月桂酰基乙二胺二乙酸钠(LEDC)。通过IR和1HNMR对产物进行结构表征。测定了LEDC在水溶液中的表面活性,其临界胶束浓度(CMC)约为2.0mmol.L-1,临界胶束浓度时的表面张力(γCMC)为25mN.m-1;随着温度变化,其CMC及γCMC变化不大。LEDC的泡沫性能介于LAS和OP-10之间,乳化能力强于两者,在硬水中的稳定性优于LAS。     

邻甲苯双胍的合成及性能研究

以盐酸、氢氧化钠为催化剂,邻甲苯胺、双氰胺为原料,合成了一种改性双氰胺固化剂——邻甲苯双胍。讨论了盐酸的加入量及加入方式、反应温度与时间等工艺条件对产物产率的影响。用熔点测定、红外光谱和核磁共振对产物进行分析,证明合成了目标产物且纯度较高。与双氰胺相比,邻甲苯双胍能较好地溶于环氧树脂和低沸点溶剂,与环氧树脂的反应活性更高,反应温度明显降低,具有良好的中温固化性能,配制的胶粘剂贮存期并无明显缩短。     

Synthesis and properties of copolypyromellitimides

Copolyamic acids with different proportions of diamine component were prepared by polymerizing different molar ratios of diamines—benzidine (B)/4,4′-diaminodiphenyl ether (E) and p-phenylene diamine (P)/4,4′-diaminodiphenyl methane (M)—with pyromellitic dianhydride (PMDA) in dimethylacetamide (DMAc) at room temperature. Diamine component can be arranged in regular sequence through various reaction processes, such as alternating, block, and partial block copolymers. In addition, it can also be arranged in random sequence to obtain random copolymers. Thermal cyclodehydration of polyamic acids results in the corresponding polyimides. Polymers are characterized by viscosity, thermal stability, crystallinity, and mechanical strength. It was found that an increase in the proportion of more flexible diamine component (such as E and M) incorporated in polymer chain results in copolyimides with better mechanical strength and causes a fall in viscosity of copolyamic acids and a decrease in thermal stability and crystallinity of copolyimides. Within the copolymers of the same composition, the thermal stability, crystallinity, and mechanical strength of ordered polymers are superior to those of random polymers. The results of viscosity measurements imply that the anhydride-terminated prepolymer is easily destroyed by water in the solution, so that the ultimate viscosities of alternating and block copolyamic acids are inferior to those of random ones, but this phenomenon can be improved through the preparation of the partial block copolymers.     

Synthesis and properties of polyaryletherketones

Crystalline polyarletherketones of high molecular weight have been prepared previously by polycondensation of aroyl fluorides such as 4-phenoxybenzoyl fluoride in liquid HF, but not by polyether synthesis because these polymers are not soluble in the recommended (see Farnham et al., J. Polym. Sci., Al, 1967, 5, 2375) dipolar aprotic solvents such as dimethyl sulphoxide or sulpholane. We find that tough, crystalline polyaryletherketones and copolyaryletherketone-sulphones can be obtained by polycondensation of bis-4-halogenophenyl ketones (plus bis-4-halogenophenyl sulphones for copolymers) with the potassium salts of bis-4-hydroxyphenyl ketones at 280°–340°C using certain diaryl sulphones as solvents for the reactions. There is no evidence for structural anomalies in the polyetherketone made by polycondensation of bis-4-fluorophenyl ketone with the bis-phenoxide from bis-4-hydroxyphenyl ketone, but synthesis of this polymer by polycondensation of the potassium salt of 4-fluorophenyl 4-hydroxyphenyl ketone gave products containing some gel and soluble polymer in which the chains appear to be branched. Several different polyaryletherketones give almost identical X-ray diffraction patterns, and in the unit cells of these polymers (fibre repeat distance 10.0Å) ether and carbonyl linkages are interchangeable; T_g and T_m for these polymers are recorded.     

聚丙烯酰胺的合成及性能

以丙烯酰胺(AM)为单体,(NH_4)_2S_2O_8,NaHSO_3为氧化还原引发体系,采用水溶液聚合法制备聚丙烯酰胺(PAM)。研究了PAM的结构、性能和相对分子质量,同时考察了反应温度及单体、引发剂和链转移剂的质量分数对聚合反应转化率及PAM相对分子质量的影响。傅里叶变换红外光谱谱图中998 cm~(-1)处C=C双键的伸缩振动吸收峰消失以及在X射线衍射谱图中衍射角为20°～23°出现PAM特征弥散衍射峰,表明AM聚合生成了PAM。PAM热分解分3个阶段进行,其玻璃化转变温度随相对分子质量增大而升高。提高反应温度、增大引发剂和单体质量分数都可以提高单体转化率。升高反应温度、降低单体质量分数、增加引发剂和链转移剂质量分数均可以降低PAM的相对分子质量。     

Synthesis and properties of stannosilicates

The stannosilicates (MFI) containing either Sn(II) or Sn(IV) were prepared by means of hydrothermal crystallization. The high crystalline MFI structure was obtained for various Sn/Si ratios up to the value of 0.05, while the further increase in Sn loading resulted in amorphous products. The stannosilicates (II) showed some ion-exchange ability and could be modified with various cations (e.g. Cu²⁺ and H⁺). Their H-forms showed considerable activity in propan-2-ol dehydration, whereas the Sn(IV)-MFI were inactive in this reaction. Both series showed catalytic activity for 2-methyl-3-butyn-2-ol decomposition, but selectivity depended on valence of Sn and on kind of introduced cations (in the case of the Sn(II) series). In cyclohexene oxidation the samples Sn(IV)-MFI showed remarkable activity, contrary to the Sn(II) series. Nevertheless, the latter indicated some oxidation activity after modification with Cu²⁺ cations.     

Synthesis and properties of sulfated alkanolamides

High purity alkanolamides were prepared by the sodium catalyzed reaction of methyl stearate, methyl palmitate and methyl laurate with ethanolamine, 2-hydroxypropylamine, 3-hydroxypropylamine and N-methyl N-hydroxyethylamine. The effect of structure on the surface active properties of the sulfation products was investigated. Stability studies showed that sulfated N-methyl N-hydroxyethylstearamide hydrolyzed rapidly by first order kinetics in acid or base. Sulfated hydroxyalkyl primary amides hydrolyzed slower in basic media following second order kinetics. Methyl groups attached to the N atom or to C in the short aliphatic chain improved solubility but had little effect on critical micelle concentration. The alkanolamides of palmitic and stearic acids were good detergents and lime soap dispersing agents. Presented at the AOCS Meeting in Minneapolis, Minn., October 1969. E. Utiliz. Res. Dev. Div., ARS, USDA     

Synthesis and properties of cyclopropane-derived peptidomimetics

Small peptides exhibit a wide range of biological activities, but although there are some notable exceptions, they are not generally useful as drugs. This has spurred widespread interest in designing peptidomimetics and introducing them as replacements of portions of native peptides to enhance their biological properties. Special attention has been focused upon rigid replacements because of their potential to preorganize the resulting pseudopeptide in a conformation corresponding to its bound structure. Toward this goal, we invented trisubstituted cyclopropanes as novel peptidomimetics, anticipating that the cyclopropane ring would locally orient the backbone and the corresponding amino acid side chain in the biologically active conformation. Selected aspects of the syntheses and applications of these cyclopropane-derived peptidomimetics are presented in this Account.     

双癸基甲基羟乙基氯化铵的合成及其性能研究

以双癸基甲基叔胺(DMA10)、盐酸和环氧乙烷为原料,合成了双癸基甲基羟乙基氯化铵(DMHAC10)阳离子表面活性剂。通过红外光谱对其结构进行了表征,并对其表面活性、泡沫性能、润湿性能和杀菌性能进行了测试。结果表明,其cmc为10.37 mg/L,γcmc为27.35 mN/m;在二次蒸馏水中的即时泡沫高度为190 mm,在150 mg/L(以CaCO3计)的硬水中的即时泡沫高度为189 mm;润湿时间为61 s;在质量浓度为300 mg/L时,对金黄色葡萄球菌(ATCC-6538)和大肠杆菌(ATCC-8099)的杀灭率达100%。     

杂萘聚芳酰胺的合成与性能

由自制的1,2-二氢-2-(4-氨基苯基)-4-[4-(4-氨基苯氧基)-苯基]-二氮杂萘-1-酮(DHPZ—DA)、4,4’-二氨基二苯甲烷(DAPM)、对苯二胺与对苯二甲酸进行缩聚合,改变不同二胺的配比,制成一系列高相对分子质量的聚芳酰胺,其特性粘数为0．81-2.38dL／g。用傅里叶变换红外光谱和核磁共振氢谱分柝了聚合物的结构,利用差示扫描量热法和热重分析研究了聚合物的耐热性能,结果表明：聚芳酰胺的玻璃化转变温度在220℃以上,氮气气氛中．5％热失重温度在450℃以上;当DHPZ—DA的摩尔分数与DAPM的摩尔分数之和超过70％时,聚合物能溶于非质子极性溶剂中。     

Synthesis and properties of imidazole-blocked diisocyanates

Imidazole-, 2-methylimidazole- and benzimidazole-blocked hexamethylene diisocyanate and isophorone diisocyanate have been prepared and characterized by elemental analyses, IR and NMR spectroscopy. The structure–property relationship of these adducts has been established by reacting with hydroxyl-terminated polybutadiene (HTPB). The cure rate of the adduct increases from the imidazole to 2-methylimidazole and to the benzimidazole-blocked adduct. Also, the cure rate of the adducts based on hexamethylene diisocyanate is higher than those based on isophorone diisocyanate. Simultaneous TGA/DTA results also confirm this trend. The gas chromatogram of the imidazole-blocked isocyanate confirms that the thermolysis products are blocking agent and isocyanate. The solubilities of the adducts have been measured in polyether and hydrocarbon polyols: the 2-methylimidazole and benzimidazole-blocked hexamethylene diisocyanate adducts show higher solubility than the rest. © 1999 Society of Chemical Industry     

Synthesis and properties of high-modulus zeolites

Zeolites with a high silica modulus were synthesized using a hexamethylenediamine (HMDA) structure-forming addition. Their physicochemical and acid characteristics were studied. The zeolites showed high activity and stability during the conversion of methanol.     

聚羧酸系减水剂的制备及性能研究

在水溶液中,以活性单体聚合法合成了一种含羧基、磺酸基、聚氧乙烯基等功能基团的聚羧酸系减水剂,原料配比MAS∶AA∶PA=1∶3∶1,反应时间3 h,温度90℃,引发剂用量2%。该减水剂在建筑石膏中掺量为0.7%时,减水率可达18.7%,且可以抑制建筑石膏流动度经时性损失,还同时提高硬化体的强度。静电斥力和空间位阻效应的协同作用是减水剂在建筑石膏中的主要作用。     

二烯丙基甲基烷基溴化铵的合成及性能研究

以二烯丙基甲胺(DAM)和不同碳链的1-溴代烷为主要原料,合成了4种二烯丙基甲基烷基(n=4,6,8,10)溴化铵(分别标记为C4,C6,C8和C10),用IR,1HNMR和元素分析对产物结构进行了表征,并通过测定其表面活性、水溶性和絮凝性能,考察产物结构对其性能的影响。结果表明:C4~C10较佳的合成工艺条件为以丙酮为溶剂,DAM与1-溴代烷的摩尔比为1∶1.1,反应时间为64~72 h,反应温度为50~60℃,所得产物的收率分别为86.16%,78.02%,75.46%和68.10%。结构表征表明合成的产物为目标产物。性能测定表明随烷基链长度的增加,二烯丙基甲基烷基溴化铵的临界胶束浓度和相应的表面张力依次减小,分别为3.2×10-2,2.1×10-2,1.7×10-2和9.0×10-3mol/L以及40.3,38.5,34.3和33.1 m N/m;水溶性好,Krafft点均小于0℃;对高岭土和硅藻土絮凝能力的强弱次序为C10C8C6C4。     

杯[4]芳烃的合成及其抗氧化研究

以对叔丁基苯酚、甲醛、二苯醚、乙酸乙酯等为原料,采用二步法合成了具有耐高温分解性能的对叔丁基杯[4]芳烃化合物。热质量分析发现,该产品的分解温度接近400℃。同时利用膨胀计方法测定了该产物的抗氧化性能,结果发现,对叔丁基杯[4]芳烃确实具有较强的抗氧化安定性能,其抗氧化安定能力与其质量浓度的1.15次幂成正比,可作为性能优良的耐高温抗氧化添加剂使用。     

Synthesis and chemo-physical properties of hydrogels

Hydrogels are synthesized from methyl methacrylate (MMA) and N-vinyl-2-pyrrolidone (NVP) with 1,1,1-trimethylol propane trimethacrylate (TPTA) as a crosslinking agent. It was polymerized under UV radiation (365nm) with a small amount of photosensitizer, diethoxy acetophenone (DEAP), acclerator and diluent, triethanol amine (TEA). The hydrogels were characterized by measuring the water retention, dissolved oxygen diffusivity and permeability, mechanical strength, and light transparency. The hydrogels can retain water up to 80 wt.-% and the mechanical strenght is weakened as the water content is increased in the gel. The dissolved oxygen diffusivity and permeability in the swelling hydrogels are determined to be 10^?6 cm²/sec and 10¹³ cm²s^?1 Pa^?1, respectively. The light transparency is over 90% in the wave lenght ranging from 500 to 700 nm.     

TPEE弹性体合成及性能研究

简要介绍了几种热塑性弹性体,重点对TPEE热塑性弹性体合成过程、产品性能进行研究.使用10L聚合反应釜合成TPEE弹性体,使用熔体流动速率仪、注塑机、万能拉伸试验机、硬度仪、傅立叶变换红外光谱仪、热失重分析仪等手段对产品性能进行表征.     

嵌段型聚醚聚二甲基硅氧烷的合成及其界面性能

用1,1,3,3-四甲基二硅氧烷(D2H)和八甲基环四硅氧烷(D4)为原料,经酸催化平衡反应先制得双端含氢聚二甲基硅氧烷(PHMS),再将其和单烯丙基聚乙二醇甲基醚在铂催化下经硅氢加成反应合成嵌段型聚醚聚二甲基硅氧烷(PEPS).用IR和1HNMR对PEPS的结构进行了表征,并通过测定PEPS水溶液的平衡表面张力研究了其表面活性.结果表明,PEPS具有良好的表面活性,其临界胶束浓度(cmc)为0.7 g·L-1,cmc处的表面张力为25.5 mN·m-1.质量分数0.05%的PEPS水溶液在塑料薄膜上30 s时的接触角为37.2°(水在塑料薄膜上30 s时的接触角为59.3°),而铺展面积是水的5倍.