Nano-sized hydroxyapatite (HA) particles were prepared by chemical precipitation through aqueous solutions of calcium chloride and ammonium hydrogenphosphate. The influence of temperature, ripening time and calcination on the crystallinity and morphology of the HA nanoparticles were investigated. It was found that the crystallinity and crystallite size increased with the increase of synthetic temperature and ripening time. XRD and TEM results showed that the morphology change of HA nanoparticles was related to their crystallinity. High crystallinity of HA led to regular shape and smooth surface of the nanoparticles. The crystallinity of HA powders increased greatly after calcination at 650 C for 6 h but the change of the crystallite size after calcination was dependent on the crystallinity and crystallite size of ''as prepared'' HA nanoparticles.

Novel porous aminopropyllsooctyl polyhedral oligomeric silsesquioxane (POSS) modified montmorillonite clay complexes (POSS-Mts) with large interlayer distance and specific surface area have been successfully prepared via ion-exchange reaction and followed by freeze-drying treatment. The morphology of the POSS-Mts is highly influenced by the POSS concentration, pH of the suspension and drying procedure, but the interlayer distance of the POSS-Mts does not change much when the POSS concentration is above 0.4 CEC. The POSS-Mts were used as Sn-catalyst supporters to initiate the ring-opening polymerization of cyclic butylene terephthalate oligomers (CBT) for the first time. No diffraction peak was detected by wide-angle X-ray diffraction for the polymerized composites (pCBT/POSS-Mt), even at 10 wt % loading of POSS-Mt. A clay network rather than exfoliation structure was observed unexpectedly in the composites by transmission electron microscopy. The pCBT/POSS-Mt composite with 10 wt % POSS-Mt was further melt-compounded with commercial PBT resin as a master batch. The tensile properties of the resultant PBT/POSS-Mt composites were highly improved as compared to the pristine PBT due to the homogeneous dispersion of POSS-Mt in the PBT matrix.

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An ionogel incorporated into poly(2,5-benzimidazole) membranes was designed for the applications of PEMFCs in a wide temperature range.

Antiplasticization of glassy polymers, arising from the addition of small amounts of plasticizer, was examined to highlight the developments that have taken place over the last few decades, aiming to fill gaps of knowledge in the large number of disjointed publications. The analysis includes the role of polymer/plasticizer molecular interactions and the conditions leading to the cross-over from antiplasticization to plasticization. This was based on molecular dynamics considerations of thermal transitions and related relaxation spectra, alongside the deviation of free volumes from the additivity rule. Useful insights were gained from an analysis of data on molecular glasses, including the implications of the glass fragility concept. The effects of molecular packing resulting from antiplasticization are also discussed in the context of physical ageing. These include considerations on the effects on mechanical properties and diffusion-controlled behaviour. Some peculiar features of antiplasticization regarding changes in Tg were probed and the effects of water were examined, both as a single component and in combination with other plasticizers to illustrate the role of intermolecular forces. The analysis has also brought to light the shortcomings of existing theories for disregarding the dual cross-over from antiplasticization to plasticization with respect to modulus variation with temperature and for not addressing failure related properties, such as yielding, crazing and fracture toughness.

Commercially available organoclay (Closite 30B) was modified by using 3-aminopropyltriethoxysilane (APS) via a silylation reaction. Sodium clay (Closite Na) was treated by APS directly as a control. Such modified clays were further melt-compounded with polybutylene terephthalate (PBT). The morphology and properties of the modified organoclays were characterized with X-ray diffraction (XRD), transmission electrical microscopy (TEM), Infra-red spectroscopy, contact angle measurement, and thermogravimetric analysis (TGA). The effects of modified clays on the crystallization behavior of PBT were characterized by differential scanning calorimetry. The basal spacing of Closite Na was enlarged from 1.01 to 1.41 nm after APS treatment, indicating that the APS was intercalated into the clay intergalleries as a monolayer. The basal spacing of Closite 30B increased slightly after APS treatment, partially resulted from the reactions between the APS and hydroxyl groups on the intercalant of Closite 30B. Closite 30B was found to be exfoliated disorderly after melt-compounded with PBT. The APS-modified Closite 30B only dispersed as swollen elliptical clay aggregates, in which the silicate layers were orderly intercalated. TGA results showed that the decomposition temperature at 5% weight loss of Closite 30B was increased from 250 to 2708C after APS treatment. A significant increase in the degree of crystallinity of PBT was observed in the exfoliated PBT/30B composite.

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