jrups
Editor’s Choice : Delamination and Separation of Aluminum-Polyethylene-Paper Packing Material
|
|
Abstract: Delamination and separation of laminated aluminum- polyethylene-paper packaging material were conducted for recycling packaging materials. Delamination was carried out using glacial acetic acid (GAA) solution. L9 (34) orthogonal experiments demonstrate that the most significant factor is GAA concentration followed by temperature and liquid/solid ratio. The delamination time decreased sharply with increasing temperature and the GAA concentration. The packaging material was delaminated under conditions of 60 ˚C, 70 v% GAA solution, liquid/solid ratio 20:1 and delamination time 60 min, and separation of polyethylene, paper and aluminum foil was conducted through sink-float method and air separation. Polyethylene, paper and aluminum foil were separated efficiently. The recovery and purity of aluminum foil was 90.81% and 100%, respectively; the purity of polyethylene was 100%; the recovery and purity of paper was 100% and 96.03%, respectively. This study offers some technical insights for recycling of aluminum-plastic packaging. Keywords: Delamination, separation, aluminum, polyethylene, packaging material.Download Full Article |
Editor’s Choice : Innovative Rice Seed Coating (Oryza Sativa) with Polymer Nanofibres and Microparticles Using the Electrospinning Method
|
|
Abstract: Seed treatments are chemical or biological substances that are applied to seeds to control infection by disease-causing organisms, insects, or other pests. Seed treatment reduces production costs of seedlings, reduces the consumption of seeds, facilitates mechanization of sowing and improves the seedling establishment. The generation of nanofibres and microcapsules by the electrospinning technique is a novel approach for active ingredient controlled release. The study evaluates an innovative rice seed coating (Oryza sativa) with polymer nanofibres and microparticles using this method. Materials and Methods:Polymer nanofibres and microcapsules were applied by the electrospinning technique to irrigated rice seeds. The treatments consisted of: 1) Control, 2) Negative control - Polymer based microcapsule without fungicide. 3) Polymer based microcapsule with fungicide. Microbiological assays and germination tests were performed following the guidelines of the Seed Analysis Rules of the Ministry of Agriculture. Results:The applied polymer as a coating did not affect the physiological quality of the seeds, as attested by the result of the germination tests, and they proved to be effective in the control of fungi disease in crop seeds. Conclusion: The germination and phytosanitary characteristics were improved in the analyzed study. Keywords: Analytical models, dielectric mixtures, effective permittivity, dispersive models, polymers.Download Full Article |
Editor’s Choice : Mechanism of Micro-Crack Propagation in Semicrystalline Polymers
|
|
Abstract: The development and propagation of cracks is the principle reason for premature mechanical failure of polymeric materials. The well known and widely accepted fracture theories, namely the Griffith fracture theory and the Irwin model, both assume that fracture takes place through the presence of preexisting cracks in the polymer. These minor preexisting cracks, or micro-cracks, are practically present in most polymeric samples. The Griffith approach assumes that for any particular material, the fracture stress is controlled by the size of the flaws present in the structure. The control and minimization of micro-crack size during polymer processing requires an understanding of the inherent micro-crack propagation mechanism. The present research reveals a mechanism of internal stress-induced micro-crack propagation in semicrystalline polymers and describes the effect of the intricate crystalline morphological interactions on the extent and direction of intra-spherulite and inter-spherulite micro-crack propagation. In conclusion, a method for minimizing inter-spherulite micro-crack propagation is presented in this article. Keywords: Crystalline morphology, fracture, micro-cracks, internal stress, high -density polyethylene (HDPE). Download Full Article |
Editor’s Choice : Modification of Nanocrystalline Cellulose for Bioactive Loaded Films
|
|
Abstract: Despite the use of petrochemical derived packaging, many problems such as browning and food spoilage still happen in food after harvesting. There is an increasing consumers concern for food shelf life to be extended as much as possible along with a big interest in green and bioactive materials, that could be used in direct contact with aliments. In order to reach public demand, biopolymers coming from natural sources such as plants or animals have been used to replace synthetic materials. Even though natural polymers are biodegradable, they do not reach regulations required with respect to mechanical properties in commercial applications. However, the mechanical properties can be improved when reinforced with nanoparticles. Several reinforcing nanoparticulessuch as clays, silica or silver have been used for industrial applications, but cellulose nanocrystals (CNCs) are a better choice for food industry due to their biodegradable and biocompatible nature as well as their outstanding potential in improving mechanical and barrier properties of nanocomposites. CNCs consist of anhydroglucopyranose units (AGU) linked together and several functional hydroxyl groups found on its surface. Modifications of the CNC surface chemistry can give to cellulose new functionalities that open the way to the development of new bioactive reinforcement in food packaging. The present review will be focused on covalent and non covalent modifications that can be achieved on surface CNC with the aim of adding functionalities to be applied for food industry. Keywords: Food packaging, cellulose nanocrystals, CNC, acetylation, polymer grafting, TEMPO oxidation, layer-by-layer, cationic surfactants, radiation-induced polymer grafting. Download Full Article |
