含硫化合物阻燃聚碳酸酯及其阻燃机理

论述了含硫化合物(磺酸盐、磺酰胺盐)及其与聚硅氧烷等的复配物阻燃聚碳酸酯(PC)的特点、配方及性能,详细讨论了硫化合物阻燃PC的机理。为赋予PCUL94V-0或5V阻燃级,极限氧指数(LOI)达40%,所需硫化合物或复配物的添加量甚低,一般小于1%。而阻燃PC的其他性能几乎与未阻燃PC基材相仿。硫化合物在凝聚相中加速PC交联成炭,从而发挥阻燃作用,但对成炭率影响甚小,而气相阻燃作用则是次要的。硫化合物能使PC异构化及发生Fries重排而有助于交联成炭。     

多孔导电聚碳酸酯/碳黑复合材料制备

介绍了一种新颖的制备聚碳酸酯／碳黑复合材料的方法。该方法使用高速混合机把高分子树脂溶液和碳黑粉末混合而成型,通过SEM分析发现,制得的材料横截面由直径大约0．1μm的树脂纤维和乙炔碳黑的团聚物交错缠绕而成。     

Annealing polycarbonate sheets

An annealing cycle for polycarbonate sheets is proposed in this paper. Tests carried out on 0.75–3.00 mm thick sheets show the good reliability of the technique. Further confirmation can be found in practical applications reported in other papers.     

聚合物合金的摩擦磨损特性的研究

作者采用了聚合物共混技术研制了ＰＣ＋ＰＴＦＥ，ＰＣ＋ＰＴＦＥ＋ＰＰＳ两类聚合物合金，并对这些材料的摩擦学特性及其机理进行了研究。结果表明，ＰＴＦＥ的添加不仅可以提高ＰＣ的耐磨性，而且还可降低其摩擦系数；适量的ＰＰＳ的添加具有减摩抗磨作用。聚全物及其合金的摩擦特性可由粘着摩擦理论解释，其磨损过程主要受粘着，磨粒和疲劳机理控制。     

质谱法研究聚碳酸酯低聚体结构

用气相色谱 质谱和场解吸 质谱方法研究聚碳酸酯的乙醇萃取物。发现由溶剂法合成的聚碳酸酯中含有以氯酸甲酯和对 叔丁基苯酚为端基的低聚体。鉴定多达九个低聚体的结构     

叶酸修饰聚碳酸酯磁性载药微球的制备及其性能

通过十六醇(CA)引发2,2-二甲基三亚甲基环碳酸酯(DTC)开环聚合合成了聚碳酸酯(CA-PDTC),CAPDTC进一步与叶酸(FA)通过酯化反应合成了叶酸修饰的聚碳酸酯(CA-PDTC-FA)。采用FTIR、1HNMR和UVvis证实了所得产物的结构。以吲哚美辛(IMC)为模型药物,Fe_3O_4粒子为磁源,通过乳化法制备了叶酸修饰的聚碳酸酯磁性载药微球(CA-PDTC-FA@Fe_3O_4)。经X射线粉末衍射仪(XRD)、热重分析仪(TG)、动态光散射仪(DLS)和振动样品磁强计(VSM)测试,结果发现:质量分数为9.5%的Fe_3O_4粒子被包裹在聚合物微球中,微球粒径约为320 nm,具有超顺磁性,且对IMC的包载率为4.6%,载药微球在模拟人体环境(pH=7.4,37℃)下36 h后的累积释药量为20.0%,具有缓释效果。     

New findings in the catalytic activity of zinc glutarate and its application in the chemical fixation of CO2 into polycarbonates and their derivatives

A heterogeneous zinc glutarate (ZnGA) catalyst and its derivatives were prepared from various zinc and glutarate sources. The hydrothermal reaction between zinc perchlorate hexahydrate and glutaronitrile afforded ZnGA single crystals (sc-ZnGA), with a monoclinic lattice unit cell and a P2/c space group, as determined by X-ray single-crystal structural analysis. The structural details of the ZnGA catalyst are crucial in helping to elucidate its activity in the copolymerization reactions between carbon dioxide (CO₂) and alkylene oxides. X-ray absorption studies provided direct evidence that CO₂ and propylene oxide (PO) are reversibly adsorbed onto the Zn ion centers on the ZnGA surface. Compared to CO₂, PO was found to insert more easily into the Zn–O bond of the ZnGA catalyst, suggesting that the ZnGA-catalyzed copolymerization is initiated by PO rather than CO₂. The activity of the ZnGA catalyst in the copolymerization of CO₂ and PO was found to depend on the zinc source used, and its ability to produce a catalyst of large surface area and high crystallinity (≥77%). Modification of the glutarate ligand with electron-donating or withdrawing substituents failed to enhance the ZnGA catalyst activity further, indicating that glutarate is the best ligand for the Zn metal ion to achieve a high catalytic activity in the CO₂ copolymerization with PO. The ZnGA-catalyzed copolymerization was further optimized to maximize the yield of alternating poly(propylene carbonate), and also extended to the terpolymerization of CO₂ and PO with δ-valerolactone (VL). Terpolymers with high molecular weights and yields could be obtained by adjusting the PO/VL feed ratios. In addition, the terpolymers were found to exhibit excellent enzymatic and biological degradability.     

Reorganization and improvement of bulk polymers by processing with their cyclodextrin inclusion compounds

The formation of polymer-cyclodextrin inclusion compounds of polycarbonate (PC), poly(methylmethacrylate) (PMMA) and poly(vinylacetate) (PVAc) guests with host γ-cyclodextrin (γ-CD) have been successfully achieved. Coalesced bulk polymer samples were obtained by removal of γ-CD from their inclusion compounds (ICs). The chemical and crystalline structures of ICs and coalesced PC, PMMA and PVAc were studied by Fourier transform infrared spectroscopy (FTIR) and wide-angle X-ray diffraction (WAXD). The thermal transitions, thermal stability, and degradation mechanisms of the samples were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and direct insertion probe pyrolysis mass spectrometry (DIP-MS). FTIR findings indicated that the chain conformations of the bulk polymers were altered when they were included inside the CD channels and extended chain conformations were retained when coalesced from their ICs. Significant improvements were observed in the thermal transitions observed for the coalesced polymers, with glass transitions shifted to higher temperatures. The TGA results reveal that the thermal stabilities of coalesced polymers increased slightly compared to the corresponding as-received polymers. The DIP-MS observations indicated that the thermal stability and degradation products of the polymers are affected once the polymers chains are included inside the γ-CD-IC cavities.     

聚碳酸酯／马来酸酐接技高密度聚乙烯共混体系的结构研究

本文通过溶解试验和分析提取物，对ＰＣ／ＨＤＰＥ－ｇ－ＭＡＨ共混体系的微观结构、流变行为进行了研究。结果表明：在熔融共混过程中接枚于聚乙烯链上的羧酸或酸酐与聚磷酸酯发生了某种化学反应，在一定程度上改善了共混体系的相容性。     

Rubber-Toughened polymer blends of polycarbonate (PC) and poly (ethylene terephthalate (PET)

The intrinsically impact brittle nature of the PC/PET blends can be effectively toughened by incorporating butylacrylate core-shell rubber. The rubber-modified PC/PET blend possess both excellent low temperature impact properties and reduced notch sensitivity. The ductile-brittle transition temperature of the blend decreases with the increase of rubber content. The presence of rubber in the PC/PET blend does not relieve the strain rate induced yield stress increase. Two separate modes, localized shear yielding and mass hear yielding, work simultaneously in the rubber toughening mechanism. The plane-strain localized shear yielding dominates the toughening mechanism at lower temperature and results in brittle failure. At higher temperature, the planestress mass shear yielding dominates the toughening mechanism and results in ductile failure. The critical plastic zone volume can be used to interpret the observed phenomenon.