Technical possibilities for recycling plastics from agribusiness

Author(s):  
Francisco Cadena ◽  
María Belén Aldás ◽  
Alex Darío Aguilar ◽  
Allyson Inga ◽  
Daniel Cando

Plastic waste generated by the Ecuadorian agro-industrial sector represents one of the main environmental impacts, particularly in floricultural and banana production, as a result of its use as a greenhouse cover and as a protective element for the fruit cluster, respectively. The situation become more complicated because of the level of degradation caused by environmental exposure and the degree of contamination due to the use of agrochemicals that plastics present once their useful life has expired. The current research was divided into two stages: characterization of plastic waste and conditioning prior to reprocessing. The results revealed the plastic waste of the floricultural and banana sector, whose predominant material corresponds to LDPE and HDPE, respectively, presents a level of contamination that allows them to be considered as “non-hazardous” waste, which allows them to be recycled, but their processes must be properly controlled and carried out by qualified people. The level of degradation in the exposed banana bags showed losses of mechanical properties of tensile less than 50%, which means that the material is not degraded and it is feasible to recycle it directly. Additionally, the FTIR-ATR spectra on both sides of the film in the samples did not register representative bands of oxidation. On the other hand, in the greenhouse waste, the losses of mechanical properties of tensile strength above 50% as well as the noticeable formation of carbonyl groups in the structure of the material showed the degradation of the plastic. Therefore, the feasibility of recycling will depend on the incorporation of virgin material. The conditioning of the waste for subsequent recycling revealed the need of a washing process consisting of four stages: initial cleaning, pre-wash, washing, and air-drying.

2006 ◽  
Vol 2006 ◽  
pp. 1-10 ◽  
Author(s):  
Lin Jiang ◽  
Qiang Xu ◽  
Chun Pu Hu

A series of polyurethaneurea (PUU) aqueous dispersions, which were stable at ambient temperature for more than 1 year, were prepared with C36-dimer-fatty-acid-based polyester polyol, isophorone diisocyanate, dimethylol propionic acid, and ethylenediamine. The particle size of all these PUU (DPU) aqueous dispersions (<100nm) was less than that of comparable specimens, that is, poly-(neopentyl glycol adipate) polyester-polyol-based PUU (APU) aqueous dispersions, and the polydispersity index was very narrow (≤1.13). The films prepared with the DPU aqueous dispersions exhibited excellent waterproof performance, such as low amount of water absorption (1.3 wt%), and good mechanical properties (hardness and tensile strength), resulting from the strong hydrogen bonding in urea carbonyl groups and the perfect ordered structure of hard segments compared with those prepared with the APU aqueous dispersions. The surface hydrophobicity of the films prepared with modified DPU aqueous dispersions, which were modified with a fluorinated polyacrylate emulsion, was excellent, as the water contact angle on the surface of such films rose up to 100. The mechanical properties of such modified DPU films were further enhanced.


Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.


Author(s):  
K.L. More ◽  
R.A. Lowden

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.


Author(s):  
Thais Helena Sydenstricker Flores-Sahagun ◽  
Kelly Priscila Agapito ◽  
ROSA MARIA JIMENEZ AMEZCUA ◽  
Felipe Jedyn

Author(s):  
Nicholas Randall ◽  
Rahul Premachandran Nair

Abstract With the growing complexity of integrated circuits (IC) comes the issue of quality control during the manufacturing process. In order to avoid late realization of design flaws which could be very expensive, the characterization of the mechanical properties of the IC components needs to be carried out in a more efficient and standardized manner. The effects of changes in the manufacturing process and materials used on the functioning and reliability of the final device also need to be addressed. Initial work on accurately determining several key mechanical properties of bonding pads, solder bumps and coatings using a combination of different methods and equipment has been summarized.


2015 ◽  
Vol 1105 ◽  
pp. 51-55 ◽  
Author(s):  
K.M. Gupta ◽  
Kishor Kalauni

Bhimal fibres are quite a newer kind of bio-degradable fibres. They have never been heard before in literatures from the view point of their utility as engineering material. These fibres have been utilized for investigation of their properties. Characterization of this fibre is essential to determine its properties for further use as reinforcing fibre in polymeric, bio-degradable and other kinds of matrix. With this objective, the fabrication method and other mechanical properties of Bhimal-reinforced-PVA biocomposite have been discussed. The stress-strain curves and load-deflection characteristics are obtained. The tensile, compressive, flexure and impact strengths have been calculated. The results are shown in tables and graphs. The results obtained are compared with other existing natural fibre biocomposites. From the observations, it has been concluded that the tensile strength of Bhimal-reinforced-PVA biocomposite is higher than other natural fibre composites. Hence these can be used as reinforcement to produce much lighter weight biocomposites.


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