The study on bacterial cellulose (BC) nanofibers used as templates for hydroxylapatite (HAp) deposition has been investigated by our group and many other researchers. However, BC is only microscopically similar to natural collagen but not molecular structure. If protein could be introduced to the surfaces of BC nanofibers, the BC nanofibers could mimic the natural collagen fibers in terms of both shape and molecular structure. In this work, our latest results concerning the preparation of polylysine (PLL) coated BC nanofibers are reported. It is found that the e-polylysine (PLL), a natural coming peptide, was introduced to the surfaces of BC nanofibers via crosslinking method by using procyanidins as crosslinker. The bioactivity of PLL coated BC nanofibers was demonstrated by the bone-like HAp deposition throughout the scaffold in a simulated body fluid (SBF). To initiate mineralization the PLL coated BC nanofibers were immersed in 1.5 times simulated body fluids (1.5 SBF) at 37°C for 7 days. The deposited minerals on the nanofiber surfaces were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and fourier transformed infrared spectroscopy (FTIR). These PLL coated BC nanofibers were proved to act as nano templates to induce the formation of nano-sized platelet-like, calcium-deficient, B-type carbonated HAp of which the features was closed to those of biological apatite.

Apparent diffusion coefficient can be used in differentiating between synovitis and joint effusion and between bone erosion and cysts.

In recent years, due to the unique advantages of nanomaterials, they are widely used in many fields (including the field of tissue engineering, protective clothing, filters, sensors, etc.). How to prepare nanofibers has become a hot research topic. This paper outlines status quo of a class of preparing nonafibres. And this preparation is the centrifugal spinning including melt centrifugal spinning, centrifugal electrospinning and solution centrifugal spinning, which have broad prospects for development. And this paper also briefly describes theirs advantages and disadvantages. Finally, the development trend of centrifugal spinning is summarized.

When a sinusoidal vibration was superimposed in parallel on the flow direction of a polymer melt being extruded through a capillary, the shear stress and shear rate of the polymer melt were analysed with a constant velocity type dynamic rheometer of capillary (CVDRC) devised by the authors. By measuring the instantaneous data of capillary entry pressure, capillary volume flux (or absolute velocity of piston rod) and their phase difference in a vibrating force field, it was found that the relationship between the pulsating amplitude value coefficient of entry pressure and that of volumetric flowrate was an approximate power series; the wall shear stress and wall shear rate of low density polyethylene (LDPE) melt extruded dynamically under various amplitudes and frequencies also exhibited a non-linear proportional relationship.

Vane extruder is a novel equipment in which polymer mainly suffers from elongational deformation. It has the character of short thermal mechanical process so that the biodegradable polymer will less decompose during processing. Different weight ratios of thermoplastic polyurethane (TPU) were blend with polyactide (PLA) in vane extruder. The results show that TPU plays the role of toughening the PLA which is well dispersed in the PLA matrix. From the mechanical properties, for the composite with 40 wt % TPU, the elongation at break of the blend reached 335%. Meanwhile the results observed from DSC curves revealed apparent partial miscibility of the blends and enhanced crystallization ability of PLA due to the influence of elongational flow. From the DMA curves, it could be found that PLA and TPU compatibility of two phases have been improved to some extent because of the elongational deformation.