Design of Collagen-Based Hemostatic Material for Use in Plastic and Reconstructive Surgery

This study aims to develop collagen-based hemostatic materials. The sheet-shaped collagen sponge was manufactured by freeze-vacuum drying the aqueous solution of collagen (Col) and heat-denatured collagen (Col’) at a composition ratio of 2/1. The both sides or one side of sponge was treated with ultraviolet (UV) irradiation for 15 minutes to introduce intermolecular crosslinks between collagen molecules. The elution behavior of collagen sponge was investigated by immersing the sponge in water for a predetermined time and then by measuring the weight change. The double-sided UV-irradiated sponge showed very slow elution properties. On the other hand, the single-sided UV-irradiated sponge showed initially fast elution and subsequent very slow elution properties. Such initially fast elution of collagen molecules from the surface without UV-irradiation allows an adhesion of collagen sponge to the wound surface and results in hemostatic effect. In addition, the water absorption and retention properties of sponge were investigated by placing the hydrated sponge on a mesh for a predetermined time and then by measuring the weight change. The double-sided UV-irradiated sponge absorbed 81 times more water than own weight and showed a value of 45 times even after 7 days. The single-sided UV-irradiated sponge absorbed 80 times more water than own weight and showed a value of 39 times even after 7 days. The sponge with high water absorption and retention properties allows a wound healing effect because such sponge can absorb large amounts of blood plasma and exudates containing various cell growth factors. The double-sided UV-irradiated sponge is a good candidate for the wound dressing. On the other hand, the single-sided UV-irradiated sponge is a good candidate for the hemostatic material.

EFFECT OF NANO-FILLER DISPERSION ON THE THERMAL,MECHANICAL AND WATER SORPTION PROPERTIES OF GREEN ENVIRONMENTAL POLYMER

Partially exfoliated nanocomposite （2） has been synthesized by intercalation of poly（propylene carbonate） （PPC） into commercial clay, Cloisite 20B （PPC/C-20B）. Nanocomposite 2 was characterized phiso-chemically and exhibited high thermal, mechanical and anti-water sorption properties as compared to PPC and intercalated nanocomposite （1） of PPC/C- 20B having same amount of clay. TGA results revealed that the thermal decomposition temperature （Td, 50%） of 2 increased significantly, being 40 K and 17 K higher than that of pure PPC and 1, respectively, while DSC measurements indicated that the nano-filler dispersion of 2 increased the glass transition temperature from 21℃ to 31℃. Accordingly, 2 showed high elastic modulus, hardness and anti-water absorption capacity. These thermal, mechanical alad anti-water absorption improvements are of great importance for the application of PPC as packaging and biomaterials.

Influence of SiC Nanoparticles Reinforcement in Areca/Tamarind Hybrid Biopolymer Composites:Thermo-mechanical,Tribological and Morphological Features

Natural fibers are displacing synthetic fibers as reinforcement in polymer composites due to their ease of processing,low cost,wide availability,biodegradability and sustainability.In this study,industrially discarded agro-waste areca fruit husk and tamarind fruit fibers were processed and used as reinforcement with unsaturated polyester resin to create a hybrid composite containing SiC nano filler particles.The SiC nano filler particles were varied from 1 to 4 wt.%in incremental steps of 1 wt.%with a constant 40 wt.%fiber reinforcement to determine its impact on the thermo-mechanical,morphological,wear and hygro-aging properties of the developed hybrid composite.However,the composite made of 3 wt.%SiC nano filler particles exposed overall better properties with better tensile(9.137 MPa),flexural(104.056 MPa),impact(7.983 J/cm^(2)),hardness(91.577 HRRW),wear(2.2×10^(-6)µm),crystallite size(7.9 nm)and thermal stability(360℃).Further advancement in weight percent of filler material,has worsened the properties due to poor dispersion and agglomeration factors by reducing the tensile,flexural,impact and hardness characteristics by 4.6%,6.4%,4.5%and 2.18%respectively.Also,the microstructural investigation revealed the failure pattern,information on interfacial adhesion between the reinforcement,filler and matrix of the hybrid composites.In addition,the crystalline characteristics and availability of functional groups in hybrid polymer composite with 3 wt.%SiC nano filler particles were disclosed by X-ray diffraction(XRD)and Fourier Transform Infrared(FTIR)spectrum analysis,respectively.The above findings reflects that the produced hybrid polymer composites suits well for interiors of automobiles and maritime interior applications to support loads with in the specified range.