Polymeric materials from natural resource

There is a long history to extract polymeric materials from renewable resources. Now focus has been given to the study of structure-function-biodegradability relationships, preparation of composites of natural with synthetic materials for improved properties and various applications, and development of processing technologies, such as foaming technology. Study and application of other abundant non-starch part of plants, natural fibers (jute, kenaf), oil, fats and proteins are active too. 

The modern agricultural technology is ever more demanding for agrochemicals and materials and manufacts that are eco-compatible and attainable at a reasonably competitive price. In that respect, the introduction of polymeric materials from renewable resources in a large variety of agricultural applications appears to be a viable solution provided these materials may be derived from cheap raw materials and eventually from agroindustrial waste or a suitable combination of natural resources and fossil fuel. 

A plethora of chemicals are available from natural feedstocks for the production of polymers and related materials. These natural resources range from seed oils to a spider s silk. While the wide use of these materials may not be economically viable at present, as oil prices continue to rise, these materials will become more attractive commercially. In this paper, the use of triglyceride oils to form novel interpenetrating networks is reviewed, and other natural sources of reactive chemicals and their uses in polymerizations are discussed. 

Seventy years ago, nearly all resources for the production of commodities and many technical products were materials derived from natural textiles. Textiles, ropes, canvas, and paper were made of local natural fibers, such as flax and hemp. Some of them are still used today. In 1908, the first composite materials were applied for the fabrication of big quantities of sheets, tubes, and pipes in electrotechnical usage (paper or cotton as reinforcement in sheets made of phenol- or melamine-formaldehyde resins). In 1896, for example, airplane seats and fuel tanks were made of natural fibers with a small content of polymeric binders [1]. 

Natural monomers and polymers have complex structure and properties, which with proper modifications could be a substitute for today s high-performance plastic materials. Existing biodegradable polymers can be blended with different materials with the aim to reduce cost and to tailor the product for specific applications. NR and almost all other natural resources are discussed and possible modifications and the applications of these natural polymers as well as polymers from natural monomers are analyzed in this review. Further studies are required to improve the performance of these materials so that synthetic polymeric materials can be replaced by polymers derived from these renewable materials. 

The main polymeric materials are based on fossil feedstocks, and the world s growing population has led to increasing mineral oil consumption, which may result in its accelerated depletion as a natural resource [1]. Another problem is the environmental pollution resulting from the disposal of polymeric materials, which may take many years to decompose. Hence, together with the world s growing environmental awareness, the desired durability of plastic materials constitutes a disposal problem. An attempt to solve the waste problem is the use of recycling techniques. However, despite its broad acceptability, recycling alone has proved to be insufficient to solve this problem, since it is impossible to recover all... 

Efficiency developed bugles skeletons from polymeric compositions is defined by that a way of manufacturing bugles skeletons on the basis of a polymeric composition from utilized polymethylmetacrylate will allow to reduce quantity of stages of multiphase process (is excluded necessity of manufacturing of fire-resistant model at a traditional way) and to improve quality of a product. Finally we receive essential economy of material and time resources, that, naturally, reduces the cost price of process of manufacturing of all bugles a skeleton, so cost of orthopedic service for the patient. 

Interest in polymeric materials prepared from renewable natural resources, such as soybean oil, has grown over the past decade. The advantages of these polymeric materials are their low cost, availability, and possible biodegradability (Kaplan, 1998). Among agricultural resources (starch, cellulose, fibers, polylactic acid, cashew nut... 

The over growing environmental pressure caused by the wide spread consumption of petroleum based polymers and plastics has hastened the development of biodegradable and environmentally acceptable materials. Biopolymers derived from various natural resources such as proteins, cellulosics, starch and other polysaccharides are regarded as the alternate materials. Biodegradable polymeric materials derived from renewable sources are the most promising materials because of their easy availability and cost effectiveness. Biodegradable modified polysaccharides have been found to possess varied applications such as salt resistant absorption of water [109]. 

From their vast abundance, renewabihty and eco-friendly nature, it seems logical that in today s world, suffering from both the impending danger of depletion of non-renewable resources (coal/petroleum/natural gas), as well as an ever increasing waste disposal problem (due to the non-biodegradability of synthetic polymeric materials), modified polysaccharides designed for specific applications would be of immense importance. 

Polymers derived from renewable resources (biopolymers) are broadly classified according to the method of production (1) Polymers directly extracted/ removed from natural materials (mainly plants) (e.g. polysaccharides such as starch and cellulose and proteins such as casein and wheat gluten), (2) polymers produced by "classical" chemical synthesis from renewable bio-derived monomers [e.g. poly(lactic acid), poly(glycolic acid) and their biopolyesters polymerized from lactic/glycolic acid monomers, which are produced by fermentation of carbohydrate feedstock] and (3) polymers produced by microorganisms or genetically transformed bacteria [e.g. the polyhydroxyalkanoates, mainly poly(hydroxybutyrates) and copolymers of hydroxybutyrate (HB) and hydroxyvalerate (HV)] [4]. 

Bio-based materials are receiving wide attention, in consequence innovative technologies and competitive industrial products are reducing the dependence on petrochemicals for the production of polymers. Increasing concerns about the environmental degradation caused by conventional polymers have directed worldwide research toward renewable resources. Natural polymers are one of the readily available alternatives for the synthesis path of polyurethanes. The functional groups present in this kind of polymer can be activated for condensation polymerizations, and polyurethane is produced by this route. The incorporation of moieties from natural polymers into the synthetic polymer chain allows tailoring of the properties of polyurethane products for widespread application. 

As two non-petroleum chemicals readily accessible from renewable resources, both furfural and HMF are suitable starting materials for the preparation of versatile fine chemicals [14, 102-106] and can also serve as renewable monomers for preparation of sustainable polymer products [107]. Schemes 3, 4, and 5 depict the stmctures of the selected furan-based monomers [107-113]. As a typical precursor, furfural can be converted to a vast array of furan-based monomers bearing a moiety which can normally be polymerized by chain-growth polymerization mechanisms [108-113]. As shown in Scheme 3, these monomers are all readily polymerizable by chain-growth reactions. However, depending on their specific structure, the nature of the polymerization mechanism is different, ranging from free radical, cationic, anionic, to stereospecific initiation [108-113]. On the other hand, furfuryl... 

The progress of chemistry, associated with the industrial revolution, created a new scope for the preparation of novel polymeric materials based on renewable resources, first through the chemical modification of natural polymers from the mid-nineteenth century, which gave rise to the first commercial thermoplastic materials, like cellulose acetate and nitrate and the first elastomers, through the vulcanization of natural rubber. Later, these processes were complemented by approaches based on the controlled polymerization of a variety of natural monomers and oligomers, including terpenes, polyphenols and rosins. A further development called upon chemical technologies which transformed renewable resources to produce novel monomeric species like furfuryl alcohol. 

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