Materials Biodegradable

The concept of using biodegradable materials for implants which serve a temporary function is a relatively new one. This concept has gained acceptance as it has been realized that an implanted material does not have to be inert, but can be degraded and/or metabolized in vivo once its function has been accompHshed (12). Resorbable polymers have been utilized successfully in the manufacture of sutures, small bone fixation devices (13), and dmg dehvery systems (qv) (14). 

These environmental issues, created a dire need for the development of green polymeric materials, which would not involve the use of toxic and noxious component in their manufacture and could be degradable in nature. For these reasons, through the world today, the development of biodegradable materials with controlled properties has been a subject of great research challenge for the community of material scientists and engineers. 

Sinha, R.S., Yamada, K., Okamoto, M. and Ueda, K. 2002. New polylactide/layered silicate nanocomposite A novel biodegradable material. Nano Betters 2 1093-1096. 

Syntheses of aliphatic polyesters by fermentation and chemical processes have been extensively studied from the viewpoint of biodegradable materials science. Recently, another approach to their production has been made by using an isolated lipase or esterase as catalyst via non-biosynthetic pathways under mild reaction conditions. Lipase and esterase are enzymes which catalyze hydrolysis of esters in an aqueous environment in living systems. Some of them can act as catalyst for the reverse reactions, esterifications and transesterifications, in organic media [1-5]. These catalytic actions have been expanded to... 

Initially PDPs were synthesized by stepwise polycondensation of linear activated depsipeptide [93]. In 1985, Helder, Feijen and coworkers reported the synthesis of PDPs by ROP of a morpholine-2,5-dione derivative (cyclic dimer of ot-hydroxy- and a-amino acid cyclodepsipeptide, cDP) [94, 95]. The ROP method gives an alternative type of PDP by homopolymerization and also allows the copolymerization with other monomers (lactones and cyclic diesters) including LA, GA, and CL to give a wide variety of functional biodegradable materials. The synthesis of PDPs as functional biomaterials has been recently reviewed [17]. 

Current polymeric entubulization repair methods for peripheral nerve regeneration use various nondegradable and biodegradable materials. The most common nondegradable material investigated has been silicone rubber. Medical grade silicone rubber, polydimethylsiloxane, maintains its shape and can be filled with neurotrophic factors or extracellular... 

The increasing popularity of biodegradable materials, which are more susceptible to microbial attack, has boosted the demand for preservation. If the product does not already contain ingredients that are themselves preservatives, such as cationic surfactants, acids, or bases, preservatives may need to be added. The required level of preservatives can be related to water availability (AW), which is defined as the ratio between the water vapor pressure over a substance and the water vapor pressure over pure water at the same temperature [17], In general, an A W of below 70% should be targeted to prohibit microorganism growth [18],... 

Fasal or Fasalex are completely biodegradable materials of vegetal origin. Some properties are shown below ... 

Biodegradable materials are destroyed by micro-organisms into short molecules that can be assimilated by plants and other living organisms... 

There are 22 chapters in the book and they cover the most important aspects of polymers as drugs, prodrugs, dmg delivery systems, and in situ prostheses. The major features promulgated are synthesis, derivatization, degradation, characterization, application, and evaluation techniques as well as new biodegradable materials, assemblies, hydrogels, telechelic polymers, derivatized polysaccharides, micro- and nanoparticles, mimetic... 

Biogas can be used after appropriate gas cleanup as a fuel for engines, gas turbines, fuel cells, boilers, industrial heaters, other processes, or for the manufacturing of chemicals. Before landfilling, treatment or stabihzation of biodegradable materials can be accomplished by a combination of anaerobic digestion followed by aerobic composting. 

On weed-free ground, a loose mulch, 4 in (10 cm) deep, will provide effective weed control. Any weeds that may appear are easily removed. An organic, biodegradable material is the preferred organic option as a bonus, this sort of mulch will attract beetles, centipedes, and other pest-eating creatures that enjoy the dark, moist conditions. 

A mulch membrane, weed barrier, or weed control fabric is simply a sheet of synthetic or biodegradable material that forms a physical and light-excluding barrier to weed growth. Membranes can be used to clear annual and perennial weeds from open ground and beds. They are also used to prevent weeds from growing on ground that has been cleared. 

The ultrasound contrast agents are manufactured from nontoxic natural or synthetic biodegradable materials (e.g., lipids or proteins), and a small amount of an inert low-solubility non-reactive gas (e.g., perfluorocarbon). These components have been shown to be harmless to the patient unlike the tens of milliliters of concentrated viscous solutions of the widely used X-ray contrast agents (which may sometimes result in nephrotoxicity). 

Composts can be made from most biodegradable materials, and could derive from many unusual sources. If it originates from municipal solid waste, however, care should be taken that no toxic and non-degradable materials remain after the supplier s separation processes. Small pieces of brick and concrete, glass and plastic (inerts), lead residues from old car batteries and cadmium from electroplated items are possible. A useful work on specifications and recommended chemical analyses of composts is the book by Bertoldi et al., 1987. 

An additional 7 percent of biodegradable wastes were recycled in 2005 for composting. That number increased from 0 percent in 1960, 1970, and 1980, and from 2 percent in 1990, the first year in which measurable amounts of biodegradable materials were recycled in the country. 

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