The simplest definition of a polymer is a useful chemical made of many repeating units. A polymer can be a three dimensional network think of the repeating units linked together left and right, front and back, up and down or two-dimensional network think of the repeating units linked together left, right, up, and down in a sheet or a one-dimensional network think of the repeating units linked left and right in a chain. Repeating units are often made of carbon and hydrogen and sometimes oxygen, nitrogen, sulfur, chlorine, fluorine, phosphorous, and silicon. Linking countless strips of construction paper together to make paper garlands or hooking together hundreds of paper clips to form chains, or stringing beads helps visualize polymers.
PVC -based plumbing is specifically selected for handling sewage because PVC biodegrades very slowly.
Some packaging materials on the other hand are being developed that would degrade readily upon exposure to the environment. A prominent example is polyhydroxybutyratethe renewably derived polylactic acidand the synthetic polycaprolactone.
Others are the cellulose-based cellulose acetate and celluloid cellulose nitrate.
Polylactic acid is an example of a plastic that biodegrades quickly. Under low oxygen conditions biodegradable plastics break down slower and with the production of methanelike other organic materials do. The breakdown process is accelerated in a dedicated compost heap. Starch-based plastics will degrade within two to four months in a home compost bin, while polylactic acid is largely undecomposed, requiring higher temperatures.
Nevertheless, it takes many months. Many plastic producers have gone so far even to say that their plastics are compostable, typically listing corn starch as an ingredient. However, these claims are questionable because the plastics industry operates under its own definition of compostable: ASTM D  The term "composting" is often used informally to describe the biodegradation of packaging materials.
Legal definitions exist for compostability, the process that leads to compost.
Four criteria are offered by the European Union: Biodegradable technology[ edit ] Now biodegradable technology has become a highly developed market with applications in product packagingproduction, and medicine.
The biodegradation of biomass offers some guidances. This reaction occurs even without prodegradant additives but at a very slow rate. That is why conventional plastics, when discarded, persist for a long time in the environment.
Oxo-biodegradable formulations catalyze and accelerate the biodegradation process but it takes considerable skill and experience to balance the ingredients within the formulations so as to provide the product with a useful life for a set period, followed by degradation and biodegradation.
Biodegradable polymers are classified into three groups: The polymer meaning a material composed of molecules with repeating structural units that form a long chain is used to encapsulate a drug prior to injection in the body and is based on lactic acida compound normally produced in the body, and is thus able to be excreted naturally.
The coating is designed for controlled release over a period of time, reducing the number of injections required and maximizing the therapeutic benefit. Professor Steve Howdle states that biodegradable polymers are particularly attractive for use in drug deliveryas once introduced into the body they require no retrieval or further manipulation and are degraded into soluble, non-toxic by-products.
Different polymers degrade at different rates within the body and therefore polymer selection can be tailored to achieve desired release rates. Biodegradable implant materials can now be used for minimally invasive surgical procedures through degradable thermoplastic polymers. These polymers are now able to change their shape with increase of temperature, causing shape memory capabilities as well as easily degradable sutures.
As a result, implants can now fit through small incisions, doctors can easily perform complex deformations, and sutures and other material aides can naturally biodegrade after a completed surgery. Please help improve this section by adding citations to reliable sources.
Unsourced material may be challenged and removed. September Learn how and when to remove this template message There is no universal definition for biodegradation and there are various definitions of composting, which has led to much confusion between the terms.
They are often are lumped together; however, they do not have have the same meaning. Composting is a human-driven process in which biodegradation occurs under a specific set of circumstances.Biodegradation is the disintegration of materials by bacteria, fungi, or other biological means.
[a] The term is often used in relation to: biomedicine, waste management, ecology, and the bioremediation of the natural environment. A History of Polymers Professors Kinam Park & Luis Solorio Purdue University Biomedical Engineering.
This term had not yet been popul arized so there was confusion as to what it meant (paper); natural rubber (Hevea brasiliensis). SNF is the only global supplier specializing exclusively in the manufacture of Water Soluble Polymers for Water and Waste Water Treatment and leading Polymer producer who remain an independent company.
Our goal is to develop and maintain long-term, mutually . The invention relates to a method for recycling paper products glued and/or coated with polymers, wherein the paper products glued and/or coated with polymers are placed in an aqueous wastepaper suspension, said wastepaper suspension a) is broken down in the presence of at least one hydrolase, b) is broken down in an alkaline medium, and/or c) is treated in a de-inking process in an alkaline.
Polymers formed by a straightforward linking together of monomer units, with no loss or gain of material, are called addition polymers or chain-growth polymers.
A listing of some important addition polymers and their monomer precursors is presented in the following table. Abstract. Plastics have transformed everyday life; usage is increasing and annual production is likely to exceed million tonnes by In this concluding paper to the Theme Issue on Plastics, the Environment and Human Health, we synthesize current understanding of the benefits and concerns surrounding the use of plastics and look to future priorities, challenges and opportunities.