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Sunday, May 9, 2010

Types of Recyclable Plastic

# The chasing arrow symbol contains a number in the center, one through seven. Types 1, 2, and 3 are common for containers, and type 3 is also used for piping, siding, medical equipment. Type 4 is sometimes used in plastic bags and squeezable bottles, as well as various cloths. Type 5 is most often found in open-top containers, such as yogurt cups, as well as medicine bottles and other containers. Type 6 is used for egg cartons, disposable plates and cups, aspirin bottles. Type 7 plastics include a large number of plastics that don't fit into the other categories, and are often non-recyclable.

Identification recycle code

Most plastics are generally identified by numbers embossed on their bottoms enabling us to know how safe they are for home use and how to recycle them. The numbers from 1-7, indicate the type and amount of resin in them.
Regardless of the number, it doesn't guarantee that something can be recycled. That depends on the current demand or resale market for a specific plastic, the amount of recycled products that can be made from it, the cost to collect it and transport it to recycling facilities, and what it is used for once processed. At any given time, only certain types of plastics are actually recyclable; other types simply end up in landfills.
Plastics being marked with the recycling triangle of chasing arrows enclosing a number doesn't automatically mean an item can be recycled. Some plastics have no second-life use and market demand for them is minimal. The markings only indicate the resin type. The following type plastics use the following codes. Plastics without codes, even toys, should be avoided, as their content would be unknown and possibly even less safe than known unsafe products.

Poly Lactic Acid

Polylactic acid or polylactide (PLA) is a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch (in the U.S.) or sugarcanes (rest of world). Although PLA has been known for more than a century, it has only been of commercial interest in recent years, in light of its biodegradability.
Other biodegradable polymers

* Cellophane
* Plastarch material
* Polycaprolactone
* Polyglycolide
* Poly-3-hydroxybutyrate
* Zein

Very low density polyethylene (VLDPE)

Very low density polyethylene (VLDPE)
VLDPE is defined by a density range of 0.880–0.915 g/cm3. VLDPE is a substantially linear polymer with high levels of short-chain branches, commonly made by copolymerization of ethylene with short-chain alpha-olefins (for example, 1-butene, 1-hexene and 1-octene). VLDPE is most commonly produced using metallocene catalysts due to the greater co-monomer incorporation exhibited by these catalysts. VLDPEs are used for hose and tubing, ice and frozen food bags, food packaging and stretch wrap as well as impact modifiers when blended with other polymers.
Recently much research activity has focused on the nature and distribution of long chain branches in polyethylene. In HDPE a relatively small number of these branches, perhaps 1 in 100 or 1,000 branches per backbone carbon, can significantly affect the rheological properties of the polymer.

Low density polyethylene (LDPE)

Low density polyethylene (LDPE)
LDPE is defined by a density range of 0.910–0.940 g/cm3. LDPE has a high degree of short and long chain branching, which means that the chains do not pack into the crystal structure as well. It has, therefore, less strong intermolecular forces as the instantaneous-dipole induced-dipole attraction is less. This results in a lower tensile strength and increased ductility. LDPE is created by free radical polymerization. The high degree of branching with long chains gives molten LDPE unique and desirable flow properties. LDPE is used for both rigid containers and plastic film applications such as plastic bags and film wrap.

Linear low density polyethylene (LLDPE)

Linear low density polyethylene (LLDPE)
LLDPE is defined by a density range of 0.915–0.925 g/cm3. LLDPE is a substantially linear polymer with significant numbers of short branches, commonly made by copolymerization of ethylene with short-chain alpha-olefins (for example, 1-butene, 1-hexene and 1-octene). LLDPE has higher tensile strength than LDPE, it exhibits higher impact and puncture resistance than LDPE. Lower thickness (gauge) films can be blown, compared with LDPE, with better environmental stress cracking resistance but is not as easy to process. LLDPE is used in packaging, particularly film for bags and sheets. Lower thickness may be used compared to LDPE. Cable covering, toys, lids, buckets, containers and pipe. While other applications are available, LLDPE is used predominantly in film applications due to its toughness, flexibility and relative transparency.

Medium density polyethylene (MDPE)

Medium density polyethylene (MDPE)
MDPE is defined by a density range of 0.926–0.940 g/cm3. MDPE can be produced by chromium/silica catalysts, Ziegler-Natta catalysts or metallocene catalysts. MDPE has good shock and drop resistance properties. It also is less notch sensitive than HDPE, stress cracking resistance is better than HDPE. MDPE is typically used in gas pipes and fittings, sacks, shrink film, packaging film, carrier bags and screw closures.

Cross-linked polyethylene (PEX or XLPE)

Cross-linked polyethylene (PEX or XLPE)
PEX is a medium- to high-density polyethylene containing cross-link bonds introduced into the polymer structure, changing the thermoplast into an elastomer. The high-temperature properties of the polymer are improved, its flow is reduced and its chemical resistance is enhanced. PEX is used in some potable-water plumbing systems because tubes made of the material can be expanded to fit over a metal nipple and it will slowly return to its original shape, forming a permanent, water-tight, connection.

Ultra low molecular weight polyethylene (ULMWPE or PE-WAX)

Ultra low molecular weight polyethylene (ULMWPE or PE-WAX)
HDPE is defined by a density of greater or equal to 0.941 g/cm3. HDPE has a low degree of branching and thus stronger intermolecular forces and tensile strength. HDPE can be produced by chromium/silica catalysts, Ziegler-Natta catalysts or metallocene catalysts. The lack of branching is ensured by an appropriate choice of catalyst (for example, chromium catalysts or Ziegler-Natta catalysts) and reaction conditions. HDPE is used in products and packaging such as milk jugs, detergent bottles, margarine tubs, garbage containers and water pipes.

Ultra high molecular weight polyethylene (UHMWPE)

UHMWPE is polyethylene with a molecular weight numbering in the millions, usually between 3.1 and 5.67 million. The high molecular weight makes it a very tough material, but results in less efficient packing of the chains into the crystal structure as evidenced by densities of less than high density polyethylene (for example, 0.930–0.935 g/cm3). UHMWPE can be made through any catalyst technology, although Ziegler catalysts are most common. Because of its outstanding toughness and its cut, wear and excellent chemical resistance, UHMWPE is used in a diverse range of applications. These include can and bottle handling machine parts, moving parts on weaving machines, bearings, gears, artificial joints, edge protection on ice rinks and butchers' chopping boards. It competes with Aramid in bulletproof vests, under the tradenames Spectra and Dyneema, and is commonly used for the construction of articular portions of implants used for hip and knee replacements.

polyethylene vinyl acetate

Polyethylene is a thermoplastic polymer consisting of long chains of the monomer ethylene (IUPAC name ethene). The recommended scientific name polyethene is systematically derived from the scientific name of the monomer. In certain circumstances it is useful to use a structure-based nomenclature; in such cases IUPAC recommends poly(methylene) (poly(methanediyl) is an non-preferred alternative. The difference in names between the two systems is due to the opening up of the monomer's double bond upon polymerization.
The name is abbreviated to PE in a manner similar to that by which other polymers like polypropylene and polystyrene are shortened to PP and PS respectively. In the United Kingdom the polymer is commonly called polythene, although this is not recognized scientifically.
The ethene molecule (known almost universally by its common name ethylene) C2H4 is CH2=CH2, Two CH2 groups connected by a double bond, thus:
* Ultra high molecular weight polyethylene (UHMWPE)
* Ultra low molecular weight polyethylene (ULMWPE or PE-WAX)
* High molecular weight polyethylene (HMWPE)
* High density polyethylene (HDPE)
* High density cross-linked polyethylene (HDXLPE)
* Cross-linked polyethylene (PEX or XLPE)
* Medium density polyethylene (MDPE)
* Linear low density polyethylene (LLDPE)
* Low density polyethylene (LDPE)
* Very low density polyethylene (VLDPE)

Saturday, May 8, 2010

Plus size clothes

Plus size clothing is a general term given to clothing sized specifically for larger sized or overweight people.Plus-size refers generally to clothing labelled size (US) 14 / (UK) 18 and upwards for women, and for sizes over XL for men. Also called Outsize in some countries (predominantly British), this term has been losing favour since the 1990s. A synonymous term for men's plus-size clothing is big and tall.
Plus size clothing patterns have traditionally been graded up from a smaller construction pattern, however many retailers are using statistical data collected from their own measuring projects, and from specialized Body Scan Data collection projects to modernize the fit and construction of their garments. U.S. companies Lane Bryant and Catherines teamed up over a three-year period to source data to modernize the companies' garment construction. Fourteen thousand women were measured in what was the most extensive female sizing study in the U.S. in over 60 years.


A T-shirt (or tee shirt) is a shirt which is pulled on over the head to cover most of a person's torso. A T-shirt is usually buttonless and collarless, with a round neck and short sleeves. However, many people incorrectly use the term T-shirt to describe any short sleeved shirt or blouse; a polo shirt or other collared shirt is not a T-shirt. The sleeves of the T-shirt extend at least slightly over the shoulder but not completely over the elbow (in short-sleeve version). A shirt that is either longer or shorter than this ceases to be a T-shirt. T-shirts are typically made of cotton or polyester fibers (or a mix of the two), knitted together in a jersey stitch that gives a T-shirt its distinctive soft texture. T-shirts can be decorated with text and/or pictures, and are sometimes used to advertise (see human billboard).
T-shirt fashions include styles for men and women, and for all age groups, including baby, youth, and adult sizes.