Synthesised by living organisms

Synthesised by living organismsDefinition of biopolymerBiopolymers atomic number 18 naturally occurring polymers which be synthesised by living organisms. This synthesis cease occur either internally within an organisms structure, or externally in appropriate conditions. The term biopolymer alike encompasses those polymers which ar produced by the physical or chemical manipulation of outturn environments. However, depending on the terms origination, it does non strictly include those polymers produced by biological manipulating. For this reason, it is best to classify such polymers as partially synthetic biopolymers. through the chemical and physical manipulation of production environments, a large frame of biopolymers energise been synthesised. Each of these pertlyly developed biopolymers atomic number 18 available with unique and beneficial properties, along with the major power to biodegrade and go away a renewable source of tractile like visible. Reasons why biopolymers whitethorn become increasingly cardinal in fiatPetroleum derived plastics expect melodic lineed an integral relationship with modern society, providing a cheap, convenient and durable method for developing numerous consumer goods and other products. The negative impacts associated with plastic favour the use of biopolymers. such impacts, along with other genes, involve An oeruse of non-biodegradable plastics. These plastics argon produced at a outrank of over degree centigrademillion tonnes per year- consumption patterns which have lead to serious problems concerning environmental pollution, bumble management and danger to animals. An uncertainty about the approaching resources of the petrochemical industry. This industry may become obsolete or produce goods too expensive for principal(prenominal)stream consumption. The initiatives of cycle have failed to make any outstanding pull ahead over the introductory decades. The recent success of biocompatible plastics which have revolutionised the medical industry. The ability to use industrial waste (such as food waste) as a substrate for biopolymer production. This has the added good of improving waste usage and reducing other forms of pollution and treatment. ruin of electronic waste (e-waste) to recover the precious metals contained in chips and circuits. With the continued exponential function growth of the electronics industry, the illegal practice of secretly burning e-waste releases many deadly gases, especially if coated in PVC. For these reasons, much interest has arisen in the rule and development of biodegradable, renewable, practical and economically viable biopolymers to replace the synthetic plastics consumed today. The new age of renewable energy and waste management have resulted in great emphasis on the future of biopolymers and the relative efficiency of their production. Selected BiopolymerPHB is a biopolymer belonging to a group of biopolymers called polyhydroxya lkanoates (PHA). It is also classified as a polyester due to containing an ester functional group. PHB is synthesised by the polymerisation of (R)-3-hydroxybutynl-CoA.PHB is produced by bacteria as the result of physiological stress. During this process PHB acts as an energy storage grain to be used later when other energy sources are depleted. The nigh common form of PHB is poly-3-hydroxybutyrate,(as shown in the above diagram), however discussed be paltryly are the generalised nones for all PHB isomers. PHB was first discovered in 1925 by Maurice Lemoigne who reason that bacteria could produce polyesters. However Maurices discovery was not officially recognized as PHB until its rediscovery in 1957. This stimulated much interest in the future of biopolymers, an interest which has reignited in recent years due to the environmental indicate and uncertain future of the petrochemical industry. utilise traditional production methods, up to 80% of the dry weight of the bacteria ca n be composed of PHB. Properties of the biopolymer 100% biodegradable in both aerobic and anaerobic environments Biocompatible the polymer can be naturally incorporated into and decomposed by the human body Thermoplastic piezoelectric produces an electric potential when compressed 8 Low thermal stability 9 Ultra violet resistance 10 richly melt point 175C8 Low resistance towards acids and bases 10 Transparent and lustrous High crystallinity structural arrangement 8 Stiff 8 More grave then water 10 Brittle depends on the take aim of crystallinity 8 Does not have chain branching it is isotactic ( unvarying structure) and therefore flows well during bear upon8 Is not soluble in water hydrophobic 8 Has a low permeable level (penetration) for oxygen, water and carbon dioxide8Uses or potential uses of the biopolymer affinity between uses and properties PHB could become the new material for use in bottles, bags, wrapping, nappies and other disposables where biodegradability is a concern Due to the biodegradability of PHB in both aerobic and anaerobic environments (both in the presence or lack of oxygen) there is a great incentive for the potential replacement of the polymers derived from petrochemicals. PHB is also hydrophobic, has low permeability by oxygen, water and CO2, has UV resistance, high melting point, and is isotactic properties which make PHB a sufficient replacement for many plastic products. PHB can be used as a medical tool. These include surgical implants, treads and coatings. In medical applications, PHB is biocompatible with the line of business and tissues of humans and other mammals. The approach pattern metabolism of humans produces the monomer of PHB, (R)-3-hydroxybutynl-CoA,and thus does not reject the polymers use as a medical tool. Surgical implants and duds all reabsorb into the body. In the pharmaceutical industry, PHB can coat capsules and provide slow or controlled drug release. The property of biocompatibility allow s this process to occur. Also, a low permeability for O2 and H2O allows it to be released slowly.The electronics industry currently burns the plastic (usually PVC) coatings around chips and circuits to retain precious metals. PHB could provide an alternative which prevents toxic gases being released by this practice. Due to the property of biodegradability, special treatment facilities could be open up to extract the precious metals in an environmentally friendly manner. Potential benefits of the biopolymer to society and the environmentEnvironmental impacts Recycling plastic as an alternative to environmental pollution and regionfill usually requires more energy compared to creating new plastic. A biopolymer with the ability to biodegrade, such as PHB, removes the need to consider the less energy high-octane recycling method. Burning waste plastic to harness energy is an excerpt towards to landfill issue, but this releases toxic gases and increases carbon dioxide concentrati on in the atmosphere. Conversely, biological polymers form part of a natural cycle whereby carbon dioxide and water are used during photosynthesis and released during natural decomposition. The ability to synthesise PHB from a wide diverseness of carbon rich sources kernel that a secondary use or market can be found for some waste products. Using substrates such as industrial food waste and molasses from sugar affect reduces the need for the treatment and disposal of such wastes. The complete changeover to PHB from normal petroleum derived plastics would reduce landfill volumes by approximately 20%, given this is the dower composition of plastics in our rubbish. This would reduce overall volumes of pollution.Societal impacts PHB and other biopolymers have revolutionised the medical industry. PHB is biocompatible with human blood and tissues, and readily reabsorbs into the body objects such as implants and threading. The biopolymer can also be used as a material for slow releasi ng drugs. Improvements in this field are inevi fudge. Petrol derived plastics can be carcinogenic. Examples include those containing benzene and vinyl chloride. PHB is a safer material for use in containers and drink bottles where this is an inconclusive concern. Reducing the volume of landfill by 20% has the social benefit of increasing overall domestic, commercial and industrial land use. It also reduces the public eyesore the landfill creates. Production of PHB using food substrates can have negative societal impacts. A higher demand for substrates which form the staple diet of developing countries may reduce the ability of these countries to purchase this food. Such a consequence would worsen the food shortages of these developing countries.HSC Chemistry sound judgement Task 1 BiopolymersCurrent problems with the biopolymerHSC ChemistryApplying PHB as a stockpile material for petroleum derived synthetic plastics would personify substantially more and render no real perfor mance advantages other than its biodegradability. In the production of PHB foursome major factors influence overall cost the price of the substrate the rough-and-ready rejoinder achieved from that substrate the price of other input factors tedious production procedures such as the need for a pure culture of alcaligenes eutrophus The cost of harvesting the PHB directly from alcaligenes eutrophus costs approximately $8/kg. This is substantially more than the $1/kg production cost for most oil base plastics. These high costs are reflected in the relative costs of diametrical substrates. The cost of the petrochemical substrate for polypropylene is US$0.185/kg of polypropylene . This is a large variation compared to the prices of different PHB substrates given in the following table Substrate effectiveness based on substrate costs and yield of PHB SubstratePrice of substrate (US$/kg)Yield (kg/kg of substrate)Substrate exist (US$/kg of PHB)Glucose0.4930.381.350Sucrose0.2950.400.720 Methanol0.1800.4300.420Acetic Acid0.5950.3801.560Ethanol0.5020.5001.000Molasses0.2200.4200.520 discontinue whey0.0710.3300.220Corn Starch0.2200.1850.580Hemicellulose0.0690.2000.340In addition to the economical restraints of PHB, heterogeneous mechanical issues are also apparent PHB is stiff and brittle compared to polythene and polypropylene. This has hindered its wide acceptance as a practical replacement for these materials. crispiness is directly related to the degree of crystallinity in the material. At room temperature, over time, secondary crystallisation occurs and the material becomes more brittle. The polymer chains degrade during processing The effect of the mass production of PHB on the environment has not been good investigated. While the material is biodegradable and renewable, major environmental consequences not nevertheless identified may exist.Properties/production processes which need further researchThe main directions of improvement and research into modifyi ng PHB and/or its production process can be classified into two categoriesHSC Chemistry1. Methods which involve the physical or chemical manipulation of production environments Adding lubricants and plasticisers to prevent degrading of chains during processing. Researching new bacteria which naturally produce plasticisers along with the biopolymer to address the issue of brittleness. Such progress would directly reduce the production costs as the plasticisers otherwise added are expensive. Suppression of the secondary crystallisation that occurs over time Making products that are programmed degradable a biopolymer that allows you to control when and how it degrades. This will insure that the biopolymer remains practical season still in use. Investigating the influence of additives on PHB degrading and level of brittleness Increasing the productivity of processing techniques such as gibbosity the process in which blends are mixed to create a uniform product Injection shapeing the process of injecting the molten polymer into a mould to solidify Investigating which solvents used in the extraction process are most productive and efficient Distinguishing methods which decrease the production time. Time means money, and the time taken by the bacteria to produce PHB is an economical factor hindering its commercial use.