Papers by Keyword: Swelling Ratio

Abstract: Being one of the three elements of tissue engineering, three-dimensional porous structure scaffold plays an important role in tissue engineering. As it not only prvovide cells for the life, but also serves as a template to guide tissue regeneration and control of organizational structure and other functions. In this study, hyaluronic acid and gelatin are successfully cross-linked by 1-ethyl- (3-dimethylaminopropyl) -carbodiimide hydrochloride (EDC) , and compound β-TCP microspheres to prepare porous hydrogel scaffolds. The microspheres were analyzed by X-ray diffraction (XRD). The scaffolds were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). At the same time, the compressive strength, swelling ratio, degradation of the scaffold were tested. To assess the in vitro cell compatibility of the scaffolds, mouse L929 fibroblasts were seeded onto scaffolds for cell morphology and cell viability studies. The results showed that the pore size of the porous scaffold can be adjusted by changing the ratio of gelatin to hyaluronic acid (HA), increasing the proportion of hyaluronic acid in a certain range, pore size will be significantly increased. With the increase of the proportion of hyaluronic acid in the scaffold, the swelling ratio and the degradation rate also increased. The compressive strength of the scaffold increased with the increase of the proportion of gelatin. The appropriate ratio of β-TCP can promote cell growth and proliferation.

Abstract: In this paper, we intended to study and improve the mechanical properties of poly (lactic acid) (PLA) composites with cellulose fibers from recycled newspapers. The influence of cellulose fiber content on tensile mechanical properties and swelling behavior of biocomposite films were investigated. In addition, the morphological property of biocomposite films was determined by scanning electron microscopy (SEM). It was found that the cellulose fibers have directly affected to the swelling behavior of biocomposite films. In addition, it was found that the cellulose fibers were found embedded between PLA matrices, which resulting to the improvement and increase the mechanical properties of biocomposite films. These findings illustrate that the cellulose fibers from recycled newspaper possesses good fillers and could be a good alternative reinforcement for biopolymer composites.

Abstract: The paper affirms that, despite the number of works in the sludge neutralization of waste water containing heavy metal compounds, the proportion of their use remains marginal. Therefore, one of the important directions of nature protection activities and the natural resources rational use is developing a technology for processing these wastes and their involvement in the production of useful products. The research of chemical, mineralogical and granulometric composition of wastewater slurry waste neutralization in production of vanadium pentoxide and ferrovanadium alloys by OJSC "EVRAZ Vanadium Tula" has been carried out. It is proposed to use a slurry waste in the claydite gravel production technology. The introduction of 1% sludge makes it is possible to obtain the following characteristics of claydite gravel: strength brand P 25, a packed density mark - 250. The 3% increase of the sludge provides a claydite gravel with the strength brand P 15 with the packed density of 250 kg/m³.

Abstract: Super Absorbent Polymer is a new type of functional polymer material developing at a high speed since the late 70’s. It can absorb water quickly . After absorbing water it becomes a kind of achromatic hydromel, and the absorbed should be: water is hard to remove even under pressure. As a result, it is usually referred as high-absorbent polymer, super absorbent polymer retention or super absorbent polymer unnecessary . This study is concerned methods of preparation and application areas of water absorbency, the influence of the initiating agent and cross-linking agent amount on the water absorbency. When the initiating agent, cross-linking agent ratio were respectively 0. 4% and 0. 2%, the water absorbency was highest. The reversibility of PH is also discussed, as well as the best methods of preparing high-water-absorbent resin cut this.

Abstract: A superabsorbent hydrogels were synthesized by an optimized rapid solution polymerization of concertrated partically neutralized acrylic acid in the presence of an organic crosslinker agent under normal atmospheric conditions, nanosized SiO₂ spheres were added into gels to strengthen the gels and decrease the cost. The results showed that, comparing to the inorganic-free hydrogels, the addition of SiO₂ spheres cause a sligtly decreased swelling ratio with a faster swelling rate. Meantime, the strength of hydrogels increases 10-20%.

Abstract: In order to solve the deep profile control problem and improve oil recovery of the oilfield, a novel profile control agent pore-scale polymer elastic microspheres (PSPEMs) was synthesized. The swelling property of PSPEMs in aqueous solution was analyzed. Core flow test and double-tube sand pack models were used for studying profile control and flooding performance of PSPEMs in oil formation. The results show that PSPEMs have good swelling property in aqueous solution with high salinity, high temperature and high pressure. Fig 5 and Fig 6 show that PSPEMs are better than polyacrylamide polymer on profile control. Table 1 indicates PSPEMs can improve water injection profile of heterogeneous formation effectively and plug the high permeable layer first. The higher the concentration of PSPEMs, the shorter the time it spends to realize profile control. The results also confirm that use proper concentration of PSPEMs, the profile control efficiency can increase enormously.

Abstract: The microspheres(SBM) was prepared using N, N'-methylene-bis-acrylamide (MBAA) as cross-linker and K2S2O8-Na2SO3 as initiator in water-in-oil emulsion. And then the effects of the O/W ratio (v/v), the amount of cross-linker and the amount of K2S2O8-Na2SO3 on particle size and swelling ratio were investigated. An increase in particle size was observed by increasing the amount of cross-linker and the amount of K2S2O8-Na2SO3, while with decreasing the O/W ratio and the amount of K2S2O8-Na2SO3 particle size was found to decreased, which was just opposite to the trend of swelling ratio. Particle size of the microspheres is 12-65μm. Ascorbic acid was selected as a sample drug, and the function between ascorbic acid and SBM was illustrated by the three-electrode equipment. The absorption mechanism suggested that the absorption of ascorbic acid on SBM is exist and ascribes to hydrogen bond for－OH and－NH2 of SBM and －OH of ascorbic acid.

Abstract: The hydrogels based on chitosan were prepared by Michael-type addition reaction between chitosan's primary amino groups and maleimide group terminating poly (ethylene glycol) (PEG) under mild conditions. The hydrogels were characterizatied by FTIR, TG, etc. The study on the swelling behavior indicated that the hydrogels possess pH-and thermo-sensitivity. The chitosan-based hydogels crosslinked by Michael-type addition reaction have a potential application on biomaterials due to its biodegradability, biocompatibility, less toxicity and hydrophilicity.

Abstract: A series of PAM/silica nanocomposite (NC) gels using silica sol as the inorganic component were prepared by in situ free-radical polymerization. The addition of silica sol was first used to bring silica nanoparticles to form organic (polymer)/inorganic system. Results from the swelling experiment indicated that the effect of silica particle was nevertheless rather complex as polymer/particle binding. Additionally, it revealed that the swelling ratio of the NC gels with a certain silica content increased with the increasing pH value. Moreover, it exhibited absorption of the polymer onto silica because the chemical cross-linked PAM has changed to the organic/inorganic system. The spectroscopic results showed that the silica nanoparticles formed by silica sol promoted high degree of attachment to the polymer chain. The AFM micrographs displayed that silica particles were of nano degree and in the monodisperse. Both evidences proved that the organic/inorganic system was effectively formed through the addition of silica sol.

Abstract: The skin is the largest organ in the body composed of the epidermis, dermis, and subcutaneous tissue through the latter it is integrated with deeper tissues. The major function of the skin is to shield out attacks, acting as a barrier. The skin can trigger a series of self-healing procedure when it is damaged. The healing process can be divided into three phases: inflammatory, tissue hyperplasia, and tissue reconstruction. Particularly during tissue hyperplasia, fibroblast proliferation and collagen deposition play important roles in the healing. The healing could be accelerated if wound dressing can be properly applied. An ideal wound dressing is capable of absorbing tissue fluid, keeping the wound moistured, stopping bleeding, attaching to the wound surface properly without sticking to the wound tissues, protecting the wound from infection, and accelerating the wound recovery. In this study, the composite membranes was made by adding mixed solutions of low-methoxyl pectin and Bletilla striata, which is a traditional Chinese medicine, into calcium chloride solution. The low-methoxyl pectin is cross-linked with calcium ions, forming a hydrogel. Membranes of varying ratio of the low-methoxyl pectin and Bletilla striata were prepared seeking for the optimal manufacturing parameters to use to investigate its effects on the water stability, water retention, contact angle and degree of swelling of the composite membranes. The results showed that when the ratio of low-methoxyl pectin solutioin (2 wt%) and Bletilla striata extract is 80/20 was added into 40 ml of 0.3 wt% calcium chloride solution, the composite membrane had the optimal performance in terms of the water stability, water retention, and swelling.