Papers by Keyword: Biodegradable Polymer

Abstract: The food contamination for pathogenic microorganisms is a serious problem for the food security. Many actions can be taken in order to reduce this pathogenic multiplication, highlighting the use of active packaging for the food conservation, which have antimicrobial agents dispersed in its surface. The metal oxides and its nanoparticles have been shown effective additives for this purpose. With the growing concern with the environmental and the use of less aggressive materials, biodegradable polymers emerge like a good alternative. This work has the goal to investigate the effect on antimicrobial activity against Gram negative (Escherichia coli) and Gram positive (Staphylococcus aureus) bacteria when added zinc oxide nanoparticles (ZnO NPs) in concentration of 1% (wt/wt) in the biodegrable polymer Ecoflex^®. The system was homogenized and proccessed in industrial extruder single screw and the polymer’s antimicrobial activity was evaluated by the agar diffusion tests and counting surviving microorganisms with the time. The results showed that the biodegradable polymer Ecoflex^® with ZnO NPs exhibit good antibacterial activity.

Abstract: The chitosan starch film was produce through solution casting with different carboxylic acid for acid treatment. Several testing were conducted such as tensile test, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), moisture absorption and soil burial. The optimum ratio for the chitosan/starch was 70:30. This ratio shows the highest tensile strength which is 11.84 MPa for the control film. The acid used for chemical modifications were citric acid and ascorbic acid. This acid modificationsexhibited higher tensile strength, Young's modulus, and less weight loss in soil burial and lower percentage of moisture absorption. SEM shows the better solubility of the starch in film with acid treatment. Moisture absorption and weight loss in the soil burial test was lower in the film with acid treatment than thefilm without acid treatment.

Abstract: The influence of molecular weight of poly (D-lactide) (PDL) on the melt crystallization was successfully investigated by non-isothermal differential scanning calorimetry (DSC) technique. The synthesized PDLs with three different number average molecular weights (Mn) of 2.39×10⁵ (PDL1), 1.09×10⁵ (PDL2) and 0.61×10⁵ (PDL3) were utilized in this study. From DSC kinetics analysis, it was found that the rate of PDLs crystallization increased with increasing cooling rate. Furthermore, the crystallization rate of PDLs was dependent on molecular weight and determined to be in the following order: PDL3 > PDL2 > PDL1. The crystallization mechanism was analyzed by the Avrami, Ozawa and Liu models. The mechanism of all PDLs crystallization was nucleation with three dimensional growths. Furthermore, the molecular weight of PDLs affected not only the crystallization rate but also the thermal property. As the molecular weight of PDLs increased, the melting temperature (T_m) increased but the heat of melting (∆H_m) decreased.

Abstract: In this study, cellulolytic enzyme lignin (CEL) was blended with polycaprolactone (PCL) by twin-screw extrusion and injection molding. The thermal, mechanical properties and the morphology of the PCL/CEL blends were investigated as a function of CEL content. The results showed that the CEL in the blends acting as nucleus accelerated the crystallization of PCL when CEL was not more than 10 wt%, but retarded PCL to crystallize with more CEL addition. Thermogravimetry analysis (TGA) revealed that the thermal stability of the PCL/CEL blends was almost unaffected by increasing CEL content. Mechanical test showed that, although the elongation at break and the impact strength were decreased, the strength and the modulus of the PCL/CEL blends were significantly higher than those of the neat PCL. Scanning electron microscopy (SEM) observations indicated that the CEL and the PCL were in good miscibility and there was a good adhesion at the interface of the CEL filler and the PCL matrix, suggesting that CEL could be potential filler used in PCL-based materials to reduce the cost of the friendly material, whereas increased its strength and modulus.

Abstract: In recent years the search for biodegradable polymers has excelled due to environmental issues. Among the biodegradable polymers from renewable sources, the poly (lactic acid) - PLA is one of the most widely used commercially, and several researches are being developed in order to improve their properties and thus increase its commercial applicability. Thus, this work aims to study the effects of incorporating polymer modifier (MBS Copolymer, Biostrength 150 - B150) and organoclay (Brasgel PA) in the properties of PLA. The study was conducted in two stages: with and without clay, and both with the B150. The concentrations used were 90/10 (PLA / modifier) and 3pcr (parts per hundred resin) of organoclay. The results showed that the mechanical properties of tensile and impact PLA significantly improved by using the polymeric modifier, indicating a gain in impact strength without a significant loss in modulus of elasticity.

Abstract: In this study bionanocomposites were prepared from biodegradable polymer matrices such as poly (lactic acid) (PLA) and PBAT/PLA blend commercially known as Ecovio^®, with abundant smectite clays in Paraíba and modified (OMMT) with Praepagen quaternary ammonium salt. Systems with PLA and with the blends of PBAT/PLA were prepared with addition of bentonite clay at a concentration of 3wt.%. in a twin screw corrotational extruder. The systems containing PLA/OMMT and blend of PBAT/PLA/OMMT were characterized by X-ray diffraction (XRD) and Heat Deflection Temperature (HDT). From the diffractograms of bionanocomposites PLA/OMMT and PBAT/PLA/ OMMT it was observed a probably microcomposite structure. It was also observed that the HDT of PBA/PLA/OMMT and the blend of PBAT/PLA bionanocomposites was lower in relation to pure PLA and its PLA/OMMT bionanocomposite.

Abstract: Although the degradation modeling of tissue engineering scaffold is in its initial step, it can direct the design, optimization of scaffold and help the application in medical case of illness. This paper analyzes the modeling methods and gives the speciality of every model which is put forward by researchers in China and abroad about the degradation of tissue engineering scaffold. These models are divided into micro scale, macro scale and two scale models based on the modeling scales. The recent research is belonging to single scale modeling. Some researchers abroad probed to two scale modeling. The future model is prospected in multi scale coupling macro, micro, and meta-macro model.

Abstract: In this article a model based on cellular automata (CA) is proposed to simulate the degradation for biodegradable polymer. The transformational rule of this model is constructed based on the hydrolysis reaction, oligomer diffusion equations and the relationship between intensity and number average molecular weight of the polymer. Furthermore, polymer DLPLA plate corresponding to this CA model was carried out. The simulation shows the middle hollow result which is accordance with the experiment phenomenon. The molecular in the degradation process has good fit with the experiment data. It proves that the model in this article is right and can provide numerical lead for the designs of biodegradable polymer devices.

Abstract: The increasing interest in green energy storage materials for electrochemical devices with the development of polymer as electrolytes candidate has attracted great attention recently. It can offer a number of high-value opportunities, provided that lower costs can be obtained besides environmental friendly. Due to this attention, the development of biodegradable polymer electrolytes (BPEs) has been accomplished in this work by incorporating various composition of dodecyltrimethyl ammonium bromide (DTAB) with carboxy methylcellulose (CMC) via solution casting method. The highest ionic conductivity of the BPEs obtained at room temperature is 7.72 x 10^-4 S cm^-1. The solid-state battery were fabricated with the configuration of Zn + ZnSO₄.7H₂O | BPEs | MnO₂ for the highest conductivity. The open-circuit voltage (OCV) of the fabricated battery with the best performance is 1.33 V at ambient temperature. The performance of the battery at ambient and selected temperature is evaluated to ascertain the effective and viability of these BPEs in solid-state batteries.

Abstract: This study showed the effect of different compounding methods on the impact resistance and tensile properties of poly(lactic acid) blended with cassava starch and natural rubber latex. Poly(ethylene glycol) was used as a plasticizer. It was found that the compounding method was important for the derived mechanical properties of the blend. Furthermore, cooling method of the extrudate also affected the mechanical properties of the blends. The air cooling in the extrusion process provided higher mechanical properties than the water cooling. This work also showed the effect of the natural rubber in the PLA/starch blend.