Journal of metals, materials and minerals 

About: Journal of metals, materials and minerals is an academic journal. The journal publishes majorly in the area(s): Chemistry & Ultimate tensile strength. It has an ISSN identifier of 2630-0508. Over the lifetime, 528 publications have been published receiving 2396 citations.

Properties of collagen/chitosan scaffolds for skin tissue engineering

Abstract: Biopolymer blends between collagen and chitosan have the potential to produce cell scaffolds with biocompatible properties. In this study, porous scaffolds were fabricated by freeze drying the solution of collagen and chitosan and crosslinked by dehydrothermal treatment (DHT). Various types of scaffolds were prepared by varying compositions of collagen and chitosan. The scaffolds were fully characterized by Fourier transform infrared (FT-IR) spectroscopy. The results proved that collagen and chitosan scaffolds in all blending compositions contained only physical but not chemical interaction in molecular level. The compressive modulus from a universal mechanical testing machine decreased with increasing the compositions of chitosan. Equilibrium swelling ratios of approximately 6-8, carried out in phosphate buffered saline (PBS) at physiological pH (7.4) were found in case of collagen dominate scaffolds. The lysozyme biodegradation test demonstrated that the presence of chitosan could significantly prolong the biodegradation of collagen/chitosan scaffolds. The collagen/chitosan scaffold was more effective to promote and accelerate L929 cell proliferation, particularly for scaffolds containing 30% of chitosan. The results elucidated that the blends of collagen with chitosan have a high possibility to be applied as new materials for skin tissue engineering.

Application of chitosan in rice production

Abstract: Chitosan is a natural biopolymer which stimulates growth and increases yield of plants as well as induces the immune system of plants. The objectives of this study were to determine appropriate applications for increasing of the rice yield. The experiment was performed with randomized complete block design (RCBD) with four replications. Four treatments were done as follows: no chitosan application, seed soaking with chitosan solution, seed soaking and soil application with chitosan solution and seed soaking and foliar spraying with chitosan solution. The results showed that application of chitosan by seed soaking and soil application four times throughout cropping season significantly increased rice yield over the other treatments whereas application by seed soaking and spraying the foliar four times tended to show an ability on disease control. However, it did not show statistically significant differences when compared with the control.

Nano-size hydroxyapatite powders preparation by wet-chemical precipitation route

Abstract: In this study, wet-chemical process was performed to prepare nano-size hydroxyapatite (HA) powders (≈10 nm) by varying concentration (low, medium and high) of the starting solutions in order to increase the amount of as-dried HA powders with different process conditions. Particle sizes and density were analyzed and differential thermal analysiswas used to determine the glass transition (T g ) and the onsetcrystallization (Tc) temperatures. XRD and SEM were performedto identify phases and microstructure. The wet-chemical precipitation using low concentration ofstarting solution under reflux environment could be the optimize process to induce the formation of hydroxyapatite rather than tricalcium phosphate even though obtaining a smaller amount of as-dried powders comparedto using high concentration. In addition, the density at 4.05 g/cm 3 and specific surface area at 89.58 m 2 /g as well as a uniform grain size morphology with a small size distribution can be achieved by using this route.

Comparison of gelatin and collagen scaffolds for fibroblast cell culture

Abstract: Gelatin and collagen were used to produce the scaffold for fibroblast cell culture. The properties of scaffolds obtained from type A and type B gelatin were compared to scaffold obtained from collagen, which is widely used in skin substitute. Porous scaffolds were prepared by freeze drying and dehydrothermal (DHT) crosslinking method. DHT treatment time was performed at 24 and 48 h and the degree of crosslinking was determined by 2,4,6-trinitrobenzene sulphonic acid (TNBS). The morphology of scaffolds was investigated by scanning electron microscopy (SEM). The compressive modulus and swelling ratio of the scaffolds were reported. To confirm the applicability of the scaffolds as a skin substitute, in vitro cell adhesion and cell proliferation tests were employed in this study. The gelatin scaffolds showed comparable properties, especially cell proliferation, to those of collagen scaffolds but the rapid degradation rate of gelatin was the limiting factor of using gelatin in wound healing. However, gelatin scaffolds could be modified to reduce the degradation rate and used substitute collagen scaffold to reduce the cost of materials for scaffold fabrication.

Processing and properties of palm oil-based rigid polyurethane foam

Abstract: Rigid polyurethane (PU) foam has been prepared from palm oil-derived polyol. The polyol was synthesized by transesterification reaction of palm oil and pentaerythritol using calcium oxide as a catalyst. The obtained palm oil-based polyol was reacted with commercial polymeric diphenylmethane diisocyanate in the presence of water (blowing agent), N,N-dimethylcyclohexylamine (catalyst) and polydimethylsiloxane (surfactant) to produce rigid PU foam. The effects of the amount of the catalyst and surfactant on foam properties (i.e. density, compressive strength and thermal behaviors) were studied. It was found that the density of the foams decreased whereas the compressive strength increased with the increasing amount of catalyst and that they were in the range of 38.7-59.0 kg/m3 and 193.6-268.4 kPa, respectively, while an increased amount of surfactant showed negligible effect on these two properties. Furthermore, TGA revealed that the degradation temperature of the prepared foams was about 377°C. Moreover, scanning electron micrographs showed that the cells of the obtained PU foams were closed cells. In addition, the foams were found to have higher number of cells as the concentration of catalyst increased, while the uniformity of cells increased with increasing amount of surfactant.