نتایج جستجو برای: waste polymers
تعداد نتایج: 151822 فیلتر نتایج به سال:
The barrier resistance and wettability of papers are commonly controlled by the application of petroleum-based derivatives such as polyethylene, waxes and/or fluorderivatives as coating. While surface hydrophobicity is improved by employing these polymers, they have become disfavored due to limitations in fossil-oil resources, poor recyclability, and environmental concerns on generated waste wi...
Lack of degradability and the closing of land)ll sites as well as growing water and land pollution problems have led to concern about plastics. Increasingly, raw materials such as crude oil are in short supply for the synthesis of plastics, and the recycling of waste plastics is becoming more important. As the importance of recycling increases, so do studies on elucidation of the biodegradabili...
Despite all the technical and economic problems and the public discussions on the environmental dangers and hazards of chlorine chemistry, poly(vinyl chloride) (PVC) is the second most produced plastic (with a worldwide capacity of about 31 million tons), placing after polyolefins and before styrene polymers. Presently, PVC production worldwide is growing at a rate of more than 4% per year. The...
The depolymerization of polymers by enzymes is of great interest for biodegradable plastics, a group of materials which has been developed as an answer to increasing problems in plastics waste management. Polyesters play the dominant role in biodegradable polymers and recently a model of polyester degradation by hydrolyses (lipases) has been published. The chain mobility of the polymer chains p...
Solid-supported catalysts enable the replacement of solutionbased catalytic chemical processes leading to facile separation of products from the reaction medium, fewer byproducts, lower energy consumption, and less environmental pollution. Recently, this catalytic method has received a lot of attention provided that it could apply to enhance the conversion of a variety of biopolymers into fuels...
The effects of additions of three wastes from sugar mills on the properties of an acid soil were investigated. The wastes used were boiler ash and filter cake from a conventional milling operation and fly ash from a new milling process, where filter cake is burnt in the boilers. Additions of each of the wastes at two sites raised soil pH and increased maize yields in a pot experiment; the effec...
Plastics debris in the marine environment, including resin pellets, fragments and microscopic plastic fragments, contain organic contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons, petroleum hydrocarbons, organochlorine pesticides (2,2'-bis(p-chlorophenyl)-1,1,1-trichloroethane, hexachlorinated hexanes), polybrominated diphenylethers, alkylphenols and bis...
In the last few decades, there has been a dramatic increase in industrial and urban activities, culminating in the need for people to adopt improved living conditions. This has led to an increase in the use of packaging materials, mainly in the form of plastic. Plastics have become an indispensable part of today’s world. Due to their lightweight, durability, energy efficiency, coupled with ease...
Lignin, the plant cell wall polymer that binds fibers together but makes processing difficult, is traditionally formed from three monomers, the so-called monolignols (p-coumaryl, coniferyl, and sinapyl alcohols). Recently, we discovered, in grass lignins, a phenolic monomer that falls outside the canonical lignin biosynthetic pathway, the flavone tricin. As we show here, palm fruit (macaúba [Ac...
This work involves the degradation of plastic waste in the presence of three different nanocatalysts. A thin film of LLDPE was formed with all three nanocatalysts separately in the solvent. Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetric (DSC) analysis of polymers suggest that the presence of these catalysts lowers the degradation temperature and the change mechanism of...
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