Utilization of polymers as biomaterials has greatly impacted the advancement of modern medicine. Specifically, polymeric biomaterials that are biodegradable provide the significant advantage of being able to be broken down and removed after they have served their function. Applications are wide ranging with degradable polymers being used clinically as surgical sutures and implants. To fit functional demand, materials with desired physical, chemical, biological, biomechanical, and degradation properties must be selected. Fortunately, a wide range of natural and synthetic degradable polymers has been investigated for biomedical applications with novel materials constantly being developed to meet new challenges. This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications.

Biomedical applications of biodegradable polymers

As a result of its impressive 3D network structure form, a great deal of interest has thus been generated among the science community on the hybridization of carbon fiber (CF) and carbon nanotube (CNT). Although there had been a large amount of studies conducted on this novel hybrid material, there are however, limited reviews being published on their fabrication methods and performances in polymer composites. For this reason, apart from collectively introducing and discussing the advantages and limitations of the hybrid CF-CNT based on various fabrication methods such as those of chemical vapour deposition, electrophoretic deposition, electrospray deposition and chemical functionalization, this study had also examined and compared the detailed performances of each of the hybrid CF-CNT reinforced polymer composite based on their fabrication methods through its mechanical, electrical and thermal properties.

Hybrid carbon fiber-carbon nanotubes reinforced polymer composites: A review

Previous synthesis routes created apatites in low crystallinity and high crystallinity states, but a wider range will extend the design capabilities of apatites for hard tissue replacements. While high crystallinity apatites are more conventional, this work investigated lower crystallinity variations from an amorphous state to low crystallinity apatite. Carbonated hydroxyapatite was prepared by precipitating an amorphous phase followed by crystallization at 650 °C at slow (5 °C min−1) and fast heating rates (60 °C min−1). The effect of processing conditions on crystallinity and structural changes was evaluated by thermal analysis, X-ray diffraction, transmission electron microscopy, Fourier transform infrared and Raman spectroscopy. Furthermore, peak deconvolution of IR and Raman spectra resolved the carbonate and phosphate bands and revealed the carbonate and crystalline phase content in CHAp. Similar to precipitation of crystalline apatites, the crystallization at elevated temperature led to carbonate in both the phosphate and hydroxyl positions. Heating at 650 °C provided a nanosized spherical hydroxyapatite containing carbonate controlled by the heating rate. This creates a mechanism for creating a large range in crystallinity with a greater resorption capability for regenerative medicine.

Effect of Processing Conditions on the Crystallinity and Structure of Carbonated Calcium Hydroxyapatite (CHAp)

Abstract Sodium silicate glasses with a wide range of water contents were prepared. For water contents up to twelve wt% the specimens were prepared by melting Na 2 O·3 SiO 2 glass and varied amounts of water in hydrothermal pressure vessels. A few higher water content samples were synthesized by hydrating glasses in an autoclave under a steam atmosphere. The concentration of different species of water was analyzed by infrared spectroscopy. Density refractive index and the induced absorption due to γ-irradiation were analyzed in terms of the different water species present in the glasses. It has been observed that the effect of water on all these properties can be explained in terms of the different contributions of hydroxyls and molecular water.

Pengfei Liu

Papers

Microstructure and mechanical properties of in-situ grown mullite toughened 3Y-TZP zirconia ceramics fabricated by gelcasting

Influence of carbon coating with phenolic resin in natural graphite on the microstructures and properties of graphite/copper composites

Tribological behavior and mechanism of h-BN modified copper metal matrix composites paired with C/C–SiC

Indentation cracking and deformation mechanism of sodium aluminoborosilicate glasses

Competitive effects of free volume, rigidity, and self-adaptivity on indentation response of silicoaluminoborate glasses