印度尼西亚化石树脂的光致发光特征研究

紫外灯下,化石树脂常见荧光现象,但其磷光现象仍有待表征与研究.将印度尼西亚产出的类似多米尼加蓝珀的化石树脂分为白色包体(PartⅠ)、暗色包体(PartⅡ)和基底(PartⅢ)三个部分,使用红外光谱确定其植物来源,借助三维荧光光谱仪表征化石树脂的光致发光现象(包括荧光和磷光),并探讨印尼化石树脂发光现象随地质过程变化的...     

高层空间框架结构动力分析的超级元子结构模型

本文将超级元和子结构的思想相结合,根据框架结构的变形特点,建立了高层空间框架结构动力分析的超级元子结构模型。模型中将楼面划分为子结构,在总结构层次将各子结构假想为二维连续体后用超级元来描述,而在子结构内部仍用经典有限元三维梁单元模拟。据此,框架梁位于同一超级元内,而框架柱连接不同的超级元。通过假设子结构内部结点自由度与总结构结点自由度的位移关系,得到超级元的质量矩阵以及框架梁和框架柱的单元刚度方程。该模型中空间框架结构的动力和非动力自由度均有大幅度的缩减,而刚性楼面假定可以进一步减少计算量。最后通过一幢30层钢筋混凝土空间框架结构的动力特性分析验证本文理论的正确性和适用性。     

脲醛树脂粘合剂的制备

介绍了含游离甲醛低的粘结强度大的建筑行业用脲醛树脂粘舍荆的制备方法。研究了树脂合成过程中原材料纯度、尿素和甲醛的摩尔比、反应温度以及反应时间等对粘度和固含量等性能的影响。在一定酸度和温度条件下,分批加入尿素进行阶段反应,得到一种胶液性能稳定、粘接强度高的建筑板材用粘合剂。     

Study on intercalation and exfoliation behavior of organoclays in epoxy resin

Intercalation and exfoliation behavior of organoclays in epoxy resin has been studied through XRD and DSC. It was found that the organoclays were easily intercalated by epoxy oligomer to form a stable epoxy/clay intercalated hybrid. Under appropriate conditions the clays were able to be further exfoliated as the epoxy resin was cured; thus, a nanocomposite was obtained. It was also found that the exfoliating ability of the organoclays was basically determined by the nature of the clays and the curing agent used. The exfoliation mechanism is discussed in this paper. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 115–120, 2001     

The effect of the curing agent content on the curing and liquid‐crystalline phase of liquid‐crystalline epoxy resin

The effect of the curing agent content on the curing behavior and liquid‐crystalline (LC) phase of the liquid‐crystalline epoxy (LCE) resin 4,4′‐di(2,3‐epoxypropyloxy)phenyl benzoate was studied. Diaminodiphenylester (DDE) was used as a curing agent. The curing behavior was observed via differential scanning calorimetry, and the LC phase was investigated with a polarized optical microscopy. The LC phase in the LCE/DDE mixture with a high DDE content was developed during curing. The onset time was inversely proportional to the DDE content. The mesophase stability of LCE/DDE was enhanced by the addition of large amounts of DDE. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 374–379, 2001     

Intractable high‐Tg thermoplastics processed with epoxy resin: Interfacial adhesion and mechanical properties of the cured blends

The intractable, high‐temperature‐resistant thermoplastics (TPs) polyphenylenether (PPE) and polyetherimide (PEI) were processed by dissolution into epoxy–amine precursors and a subsequent reaction of the precursors. Because the TP concentration was higher than the critical concentration, the phase separation produced a dispersion of crosslinked thermoset (TS) particles into a TP matrix. The morphology of the blends was examined with transmission electron microscopy and dynamic mechanical thermal spectroscopy, which showed completion of the phase separation. The interfacial adhesion at the TP‐matrix/TS‐particle interface was estimated on TP/TS bilayers to be 10 J/m² in PEI blends, whereas it was 70 J/m² in PPE blends, where there is strong evidence for in situ grafting between PPE phenolic chain ends and glycidyl functions of the reactive TS. Yielding in the compressive mode occurred at an intermediate yield stress between the components' values, and the anelastic deformation was separated from the plastic deformation. Fractures in the tensile mode occurred through debonding at the matrix/particle interfaces and coalescence of these defects, which led to microcrack formation and brittle failure. Mode I fracture toughness was, therefore, higher for PPE blends than for PEI blends, a result of the higher interfacial adhesion. However, a decrease from pure TP was observed. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 363–373, 2001     

Synthesis of hybrid resins via polysiloxane with methacryloyloxy groups

A polysiloxane derivative with methacryloyloxy groups (MPS) that was obtained from the reaction of polymeric tributylstannyl ester of silicic acid and (3‐methacryloyloxypropyl)dimethylchlorosilane was demonstrated to be a useful inorganic component for the preparation of organic–inorganic hybrid resins as nanocomposites. The copolymerizations of MPS with common monomers such as styrene, acrylonitrile, and methyl methacrylate proceeded readily at room temperature under UV irradiation to give the corresponding resins in good yields. The resins obtained from MPS and methyl methacrylate showed good transparency, hardness in a scratch test, and resistance to toluene but had poor flexibility. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1–7, 2001     

Flame‐retardant epoxy resins: An approach from organic–inorganic hybrid nanocomposites

Phosphorus‐containing epoxy‐based epoxy–silica hybrid materials with a nanostructure were obtained from bis(3‐glycidyloxy)phenylphosphine oxide, diaminodiphenylmethane, and tetraethoxysilane in the presence of the catalyst p‐toluenesulfonic acid via an in situ sol–gel process. The silica formed on a nanometer scale in the epoxy resin was characterized with Fourier transform infrared, NMR, and scanning electron microscopy. The glass‐transition temperatures of the hybrid epoxy resins increased with the silica content. The nanometer‐scale silica showed an enhancement effect of improving the flame‐retardant properties of the epoxy resins. The phosphorus–silica synergistic effect on the limited oxygen index (LOI) enhancement was also observed with a high LOI value of 44.5. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 986–996, 2001     

活性自由基聚合法合成新型裘皮型羧酸酯基功能高分子

采用原子转移自由基聚合反应(ATRP)经二步法合成了一种裘皮型羧酸酯基功能高分子.首先以氯化亚铜-联吡啶络合物(CuCl-bPy)为催化体系,以a-溴代丙酸乙酯(EBP)为引发剂、乙腈(AN)为溶剂在80℃进行甲基丙烯酸甲酯(MMA)的均相ATRP反应,合成得到带溴原子端基的线型聚甲基丙烯酸甲酯(PMMA-Br),其分子量分布呈单分散性(Mn=7.5～8.6x 104,PDI≤1.08);利用所合成PMMA-Br为大分子引发荆、二乙烯基苯(DVB)为单体(交联剂)、氯化亚铜*五甲基二亚乙基三胺(CuCl·PMDETA)为催化剂,在110℃苯甲醚(PME)溶液中进行DVB的活性原子转移自由基聚合反应,合成得到了一种12臂,臂长为120nm～140nm的裘皮型羧酸酯基功能高分子.分析结果表明,所合成裘皮树脂的尺寸均一性良好(PDI≤1.54).     

强碱阴离子交换树脂合成及热稳定性能研究

氯甲基化聚苯乙烯树脂与不同的叔胺反应制备了含不同季铵基团的强碱树脂.将氯甲基化聚苯乙烯树脂进行硝化、溴化反应后,再用三甲胺进行季铵化制备了苯环上含有吸电子基团的强碱树脂,测定了所制备树脂在水中的热稳定性.结果表明,位阻较大的季铵表现出较高的热稳定性;硝化、溴化后的树脂热稳定性有一定改善;而热重分析表明苯环上引入吸电子取代基不利于提高碱基在高温下的稳定性.