Why is the ground snow white?

While growing up as a child I would walk out of my house to go outside to play. That is what we did back then. We played outside. When I stepped outside I would be greeted  not by the site of new fallen snow but that of a white powdery substance covering our lawn. My mother would tell me, "Don't play on the lawn!"  I now know that this substance is called tinuvin. Tinuvin is a product used in the manufacturing of plastics. This Blogger has been told that the white substance covering her lawn was tinuvin. Tinuvin  comes in a multitude of forms and was found at the CG site. It was reported by the FDA that CG stated in reports that Tinuvin was used to manufacture plastics. I was told that Tinuvin is "harmless". 

Hmmmm. I think we are now told NOT to place plastic and plastic wrap in our microwave ovens today. Little did they know 25 years ago. Silly scientist.

Adverse Health Effects of Plastics

In addition to creating safety problems during production, many chemical additives that give plastic products desirable performance properties also have negative environmental and human health effects. These effects include

• Direct toxicity, as in the cases of lead, cadmium, and mercury
• Carcinogens, as in the case of diethylhexyl phthalate (DEHP)
• Endocrine disruption, which can lead to cancers, birth defects, immune system supression and developmental problems in children.

See the Adverse Health Effects Grid for a list of commonly used plastics and their known health effects.

Chemical Migration from Plastic Packaging into Contents

People are exposed to these chemicals not only during manufacturing, but also by using plastic packages, because some chemicals migrate from the plastic packaging to the foods they contain. Examples of plastics contaminating food have been reported with most plastic types, including Styrene from polystyrene, plasticizers from PVC, antioxidants from polyethylene, and Acetaldehyde from PET.

Among the factors controlling migration are the chemical structure of the migrants and the nature of the packaged food. In studies cited in Food Additives and Contaminants, LDPE, HDPE, and polypropylene bottles released measurable levels of BHT, Chimassorb 81, Irganox PS 800, Irganix 1076, and Irganox 1010 into their contents of vegetable oil and ethanol. Evidence was also found that acetaldehyde migrated out of PET and into water.

Recommendations

Find alternatives to plastic products whenever possible. Some specific suggestions:
* Buy food in glass or metal containers; avoid polycarbonate drinking bottles with Bisphenol A
* Avoid heating food in plastic containers, or storing fatty foods in plastic containers or plastic wrap.
* Do not give young children plastic teethers or toys
* Use natural fiber clothing, bedding and furniture
* Avoid all PVC and Styrene products

• Buy food in glass or metal containers
• Avoid heating food in plastic containers, or storing fatty foods in plastic containers or plastic wrap
• Do not give young children plastic teethers or toys
• Use natural fiber clothing, bedding and furniture
• Avoid all PVC and Styrene products

Plastic	Common Uses	Adverse Health Effects
Polyvinyl chloride (#3PVC)	Food packaging, plastic wrap, containers for toiletries, cosmetics, crib bumpers, floor tiles, pacifiers, shower curtains, toys, water pipes, garden hoses, auto upholstery, inflatable swimming pools	Can cause cancer, birth defects, genetic changes, chronic bronchitis, ulcers, skin diseases, deafness, vision failure, indigestion, and liver dysfunction
Phthalates (DEHP, DINP, and others)	Softened vinyl products manufactured with phthalates include vinyl clothing, emulsion paint, footwear, printing inks, non-mouthing toys and children’s products, product packaging and food wrap, vinyl flooring, blood bags and tubing, IV containers and components, surgical gloves, breathing tubes, general purpose labware, inhalation masks, many other medical devices	Endocrine disruption, linked to asthma, developmental and reporoductive effects. Medical waste with PVC and pthalates is regularly incinerated causing public health effects from the relese of dioxins and mercury, including cancer, birth defects, hormonal changes, declining sperm counts, infertility, endometriosis, and immune system impairment.
Polycarbonate, with Bisphenol A (#7)	Water bottles	Scientists  have linked very low doses of bisphenol A exposure to cancers, impaired  immune function, early onset of puberty, obesity, diabetes, and  hyperactivity, among other problems (Environment California)
Polystyrene	Many food containers for meats, fish, cheeses, yogurt, foam and clear clamshell containers, foam and rigid plates, clear bakery containers, packaging "peanuts", foam packaging, audio cassette housings, CD cases, disposable cutlery, building insulation, flotation devices, ice buckets, wall tile, paints, serving trays, throw-away hot drink cups, toys	Can irritate eyes, nose and throat and can cause dizziness and unconsciousness. Migrates into food and stores in body fat. Elevated rates of lymphatic and hematopoietic cancers for workers.
Polyethelyne (#1 PET)	Water and soda bottles, carpet fiber, chewing gum, coffee stirrers, drinking glasses, food containers and wrappers, heat-sealed plastic packaging, kitchenware, plastic bags, squeeze bottles, toys	Suspected human carcinogen
Polyester	Bedding, clothing, disposable diapers, food packaging, tampons, upholstery	Can cause eye and respiratory-tract irritation and acute skin rashes
Urea- formaldehyde	Particle board, plywood, building insulation, fabric finishes	Formaldehyde is a suspected carcinogen and has been shown to cause birth defects and genetic changes. Inhaling formaldehyde can cause cough, swelling of the throat, watery eyes, breathing problems, headaches, rashes, tiredness
Polyurethane Foam	Cushions, mattresses, pillows	Bronchitis, coughing, skin and eye problems. Can release toluene diisocyanate which can produce severe lung problems
Acrylic	Clothing, blankets, carpets made from acrylic fibers, adhesives, contact lenses, dentures, floor waxes, food preparation equipment, disposable diapers, sanitary napkins, paints	Can cause breathing difficulties, vomiting, diarrhea, nausea, weakness, headache and fatigue
Tetrafluoro- ethelyne	Non-stick coating on cookware, clothes irons, ironing board covers, plumbing and tools	Can irritate eyes, nose and throat and can cause breathing difficulties

Sources:http://www.ecologycenter.org/factsheets/plastichealtheffects.html

• Centers for Disease Control Report, "National Report on Human Exposure to Environmental Chemicals," 2001.
• Dadd, Debra, Home Safe Home, Penguin Putnam, New York, 1997.
• Ecology Center Plastic Task Force Report, Berkeley, CA, 1996.
• Goettlich, Paul, "What are Endocrine Disruptors?," 2001
• National Resources Defense Council website, "Endocrine Disruptors FAQ," 2001.

How Plastic wrap is made. http://www.madehow.com/Volume-2/Plastic-Wrap.html#b

Plastic wrap is a form of food packaging consisting of a thin film of flexible, transparent polymer that clings to itself and to food containers to form a tight seal. The plastic keeps the food fresh by protecting it from air and by preventing dry foods from absorbing moisture and wet foods from losing moisture. It also seals in odors to prevent them from spreading to other foods stored nearby.

Plastics are artificial polymers; that is, they consist of gigantic molecules formed by combining thousands of small molecules of the same kind into a long chain. These small molecules are known as monomers, and the process of combining them is known as polymerization. Natural polymers include such familiar substances as silk, rubber, and cotton.

The first plastic was made by the British chemist Alexander Parkes in 1862, who produced a substance he called Parkesine from cotton, nitric acid, sulfuric acid, castor oil, and camphor. Two years later in the United States John Wesley Hyatt improved this product and named it celluloid. Celluloid was a tremendous success and was used to make many different products, but it was highly flammable.

The first completely artificial polymer (unlike celluloid, which was a derivative of the natural polymer cellulose) was Bakelite, which was produced from phenol and formaldehyde by the Belgian chemist Leo Baekeland in 1908. Many other polymers were developed during the 20th century, including such important products as artificial rubber and artificial fibers such as nylon.

The first plastic used for wrapping was cellophane, another derivative of cellulose invented by the Swiss chemist Jacques Brandenberger in 1911. It had the advantage of being transparent, and was used for packaging as early as 1924. Cellophane was the most common form of plastic film made until 1963, when it was overtaken by polyethylene.

Polyethylene was discovered by accident by research workers at the British company Imperial Chemicals Industries in 1933, when they mixed benzene and ethylene at high temperature and pressure. Polyethylene was first used chiefly for electrical insulating material. It was first made into a film in 1945 by the Visking Corporation in the United States, and has grown in popularity ever since.

Polyvinyl chloride (PVC) was produced before World War II and was originally used as an inferior substitute for rubber, but films of this substance were not made in any quantity until the 1950s. PVC is used today in many different products such as pipes, flooring, electric cables, shoes, and clothing, as well as plastic wrap.

Polyvinylidene chloride (PVDC) film was developed by the Dow Chemical Company during World War II for military use. It offered a high degree of protection from moisture and resistance to oils, greases, and corrosive chemicals, so it was used to package sensitive equipment such as optical devices and aircraft engine components. In

1952 it was offered to the public under the familiar trade name Saran Wrap.

Raw Materials

Most household plastic wrap is made from polyethylene, PVC, or PVDC. These polymers are all derived from simple hydrocarbons such as methane or ethylene, which are produced from natural gas or petroleum. Polyethylene is made directly from ethylene. PVC is made from vinyl chloride, derived from ethylene, or from acetylene, derived from methane. PVDC is made from vinyl chloride and vinylidene chloride, a derivative of 1,1,2-trichloroethane, which in turn is derived from ethylene or acetylene.

Some plastic films, including cellophane, are derived from cellulose, which is obtained from wood pulp or from linters, tiny fibers that cling to cotton seeds after the longer cotton fibers have been removed by a cotton gin. At least one form of plastic film (Pliofilm, a trademark of Goodyear) is derived from rubber.

The Manufacturing
Process

Processing the raw materials

• 1 The chemicals needed to synthesize polymers are usually obtained from petroleum. Crude oil is heated in a furnace to about 752°F (400°C). Vapors from the oil move into a fractionating column, a tall tower containing a series of chambers. The chambers are warmer at the bottom of the tower and cooler at the top. The various substances that make up petroleum rise through the chambers as gases until they reach the temperature at which they become liquids. Since each substance has a different boiling point, they liquefy in different chambers and can be separated and collected.
• 2 Most polymers begin with very simple hydrocarbons that have low boiling points. These substances do not liquefy in the fractionating column, but instead remain in the form of gases which can be removed from the top of the tower. They may also be obtained from natural gas, which is mostly methane. Another source for these chemicals is naphtha, a mixture of liquid hydrocarbons, obtained from a fractionating column, which are heavier than gasoline but lighter than heavy oil. Naphtha is heated under pressure to break down the liquid hydrocarbons into smaller molecules, a process known as cracking. A catalyst is added to enable cracking to take place at a lower temperature and pressure than it would without it. The catalyst may be a natural or artificial clay (a mixture of alumina and silica or a zeolite (any of various minerals containing aluminum, silicon, oxygen, and other elements in combination with water.) Catalytic cracking usually takes place at a temperature of about 932°F (500°C) under a pressure of about 100 kilo-pascals. The cracked naphtha is then distilled in a manner similar to that in a fractionating column to separate its components.

Polymerization

• 3 Polyethylene is polymerized from ethylene, which is obtained from cracking. Ethylene is heated in a pressure chamber to about 338°F (170°C) at a pressure of about 200,000 kilopascals in the presence of a small amount of oxygen. The oxygen breaks the ethylene down into free radicals, which combine with each other to form chains of polyethylene. About one percent of a nonreacting gas such as propane is added to prevent the chains from becoming too long.
• 4 PVC is polymerized from vinyl chloride, which can be obtained either by mixing acetylene with hydrochloric acid or ethylene with chlorine. Ethylene is more commonly used because it is efficiently obtained from the cracking of naphtha. If acetylene is used it must first be synthesized by heating methane to about 2732°F (1500°C) or through various other chemical reactions. Vinyl chloride is mixed with water and agitated to form a suspension, much as oil and vinegar are mixed to form salad dressing. Various suspending agents such as starch and gelatin are added to keep the mixture from separating. The temperature of the suspension is raised to about 104°F (40°C) or 122°F (50°C) and an initiator, usually an organic peroxide, is added to start the reaction. The vinyl chloride molecules react with each other to form chains of PVC. The mixture is cooled and particles of PVC are separated from the water in a centrifuge and dried in an oven.
• 5 PVDC is polymerized from a mixture of about 15% vinyl chloride and about 85% vinylidene chloride. To produce vinylidene chloride, first 1,1,2-trichloroethane is made by mixing acetylene, hydrochloric acid, and chlorine, or by mixing ethylene and chlorine. The 1,1,2-trichloroethane then reacts with calcium hydroxide or sodium hydroxide to produce vinylidene chloride. Polymerization of PVDC proceeds in much the same way as PVC.
• 6 Polyethylene is naturally flexible, but PVC and PVDC must have plasticizers added or they will be hard and rigid. Various organic and inorganic esters can be used as plasticizers. Generally the liquid plasticizer is slowly sprayed into dry polymer powder and heated to about 302°F (150°C) to form a homogeneous mixture.

Making plastic wrap

• 7 Plastic wrap is made by extrusion. In this process granules of plastic are heated until they melt at about 212°F (100°C) for polyethylene and about 392°F (200°C) for PVC and PVDC. The liquid is then forced through a die to form a tube of warm, stretchable plastic. At regular intervals compressed air is blown into the side of the moving tube to form large bubbles. This stretches the plastic to the desired thinness. The thin plastic cools rapidly, and the bubble is collapsed between metal rollers to form a film. The film is wound around a large metal roller to form a roll that may hold several kilometers of plastic wrap. The plastic film on these rolls is then unrolled, cut to the proper length (usually about 49 feet [15 m]) and width (about 1 foot [0.33 m]), and rerolled onto small cardboard tubes. (This rolling, unrolling, and rerolling tends to give the plastic wrap a slight negative charge of static electricity, that helps it cling.) The cardboard tubes of plastic wrap are placed in cardboard boxes that have a serrated edge at the opening so that the consumer can tear off the desired length. Some also have a sticky spot on the box to catch the edge of the plastic wrap so it doesn't stick to the tube. The boxes of plastic wrap are then stacked in cartons and shipped to retailers.

Quality Control

A variety of standard tests exist to ensure that plastic wrap is effective. The most important are tests for permeability, impact resistance, and tear strength.

Water vapor permeability is measured by filling a dish with calcium chloride, a highly water-absorbent substance. It is covered with a sample of plastic wrap and weighed. The dish is then placed in a chamber with a controlled temperature and humidity. After a measured amount of time the dish is weighed again. The increase in weight shows how much water vapor has passed through the plastic. This test can also be done by filling the dish with water instead of calcium chloride and measuring the decrease in weight to see how much water vapor has escaped. These tests are performed at 73°F (23°C) with a relative humidity of 50%, at 90°F (32°C) with a relative humidity of 50%, and at 100°F (38°C) with a relative humidity of 90%.

Gas permeability is measured by placing a sample of plastic wrap between two chambers. The upper chamber contains a pressure of 100 kilopascals, and the lower chamber contains a vacuum connected to a tube containing liquid mercury. As the air in the upper chamber passes through the plastic wrap it increases the pressure in the lower chamber and forces the level of mercury to drop. The change in the level reveals how much air has penetrated the plastic.

Impact resistance is measured by dropping weights of increasing size on test samples until half of them break, at which point the weight is recorded. It can also be measured by filling bags made from the plastic wrap that is being tested with sand and dropping them on a hard surface from increasing heights until they burst. The height at which this occurs is then recorded. Impact resistance is also measured by shooting a small steel ball propelled by pressurized air through a sheet of plastic wrap and measuring how much the plastic slows it down.

Tear strength consists of tear initiation strength (the force required to start a tear) and tear propagation strength (the force needed to continue a tear). To measure tear initiation strength a sample shaped like a shallow V is pulled between two jaws until it begins to tear. This unusual shape is selected to provide a 90 degree angle that provides a controlled starting point for the tear. Tear propagation strength is measured by pulling apart a sample containing a precut slit.

In general, PVDC is stronger and less permeable than polyethylene, which is less permeable than PVC.

Environmental Concerns

Since plastic wrap is difficult, if not impossible, to recycle and is rarely reused, it does contribute to waste. One consumer group, considering such factors as the energy and raw materials needed for manufacture, the wastes released during manufacturing and disposal, the ability to be recycled, and the typical amounts used, has rated plastic wrap as "Good." By comparison, reusable plastic containers were rated as "Excellent," plastic bags as "Very Good," aluminum foil and freezer bags as "Good," and freezer papers as "Poor." Another concern is the possibility that exposure to certain plasticizers in plastic wrap could be harmful. These chemicals are absorbed from plastic wrap into hot and fatty foods. Although they have never been shown to cause harm in humans, plasticizers have been proved to cause cancer when fed in large amounts to lab animals. PVC wrap can consist of as much as one-third plasticizers, PVDC wrap consists of about 10% plasticizers, and polyethylene wrap usually contains no plasticizers.

Where To Learn More

Book

Gait, A. J. and E. G. Hancock. Plastics and Synthetic Rubbers. Pergamon Press, 1970.

Periodical

"Keeping Food Fresh." Consumer Reports, March 1994, pp. 143-47.

— Rose Secrest

Read more: http://www.madehow.com/Volume-2/Plastic-Wrap.html#b#ixzz2KqQmGxgw

PHTHALATES

Because all of FDA's product centers are represented on the BPA Task Force, Commissioner von Eschenbach has also tasked it with establishing a comprehensive inventory of regulated products that contain phthalates. Phthalates are primarily used as plasticizers in polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC) polymers to increase their flexibility. Di-(2-ethylhexyl) phthalate (DEHP) is perhaps the most thoroughly studied among the phthalates. DEHP has long been used to produce highly flexible versions of PVC and PVDC polymers for a variety of applications, such as in flexible packaging film.

FDA-authorized uses of phthalates include uses in flexible food packaging. Over the past decade, however, such food contact uses have been greatly reduced or eliminated through the replacement of PVC and PVDC polymers with other polymers that do not require plasticizers and by the use of alternative plasticizers in PVC and PVDC. FDA's Center for Food Safety and Applied Nutrition (CFSAN) has tracked the reductions in use of phthalates in food contact materials as well as the development of new toxicological data.

Bisphenol-A (BPA)

Statement of

Norris Alderson, Ph.D.
Associate Commissioner for Science
Food and Drug Administration
Department of Health and Human Services

before

the Subcommittee on Commerce, Trade and Consumer Protection
House Committee on Energy and Commerce

June 10, 2008

http://www.fda.gov/NewsEvents/Testimony/ucm115235.htm

Dioxins (http://en.wikipedia.org/wiki/Polyvinyl_chloride)

Main article: Polychlorinated dibenzodioxins

PVC produces HCl upon combustion almost quantitatively related to its chlorine content. Extensive studies in Europe indicate that the chlorine found in emitted dioxins is not derived from HCl in the flue gases. Instead, most dioxins arise in the condensed solid phase by the reaction of inorganic chlorides with graphitic structures in char-containing ash particles. Copper acts as a catalyst for these reactions.[35]

Studies of household waste burning indicate consistent increases in dioxin generation with increasing PVC concentrations.[36] According to the EPA dioxin inventory, landfill firesare likely to represent an even larger source of dioxin to the environment. A survey of international studies consistently identifies high dioxin concentrations in areas affected by open waste burning and a study that looked at the homologue pattern found the sample with the highest dioxin concentration was "typical for the pyrolysis of PVC". Other EU studies indicate that PVC likely "accounts for the overwhelming majority of chlorine that is available for dioxin formation during landfill fires."[36]

The next largest sources of dioxin in the EPA inventory are medical and municipal waste incinerators.[37] Various studies have been conducted that reach contradictory results. For instance a study of commercial-scale incinerators showed no relationship between the PVC content of the waste and dioxin emissions.[38][39] Other studies have shown a clear correlation between dioxin formation and chloride content and indicate that PVC is a significant contributor to the formation of both dioxin and PCB in incinerators.[40][41][42]

In February 2007, the Technical and Scientific Advisory Committee of the US Green Building Council (USGBC) released its report on a PVC avoidance related materials credit for the LEED Green Building Rating system. The report concludes that "no single material shows up as the best across all the human health and environmental impact categories, nor as the worst" but that the "risk of dioxin emissions puts PVC consistently among the worst materials for human health impacts."[43]

In Europe the overwhelming importance of combustion conditions on dioxin formation has been established by numerous researchers. The single most important factor in forming dioxin-like compounds is the temperature of the combustion gases. Oxygen concentration also plays a major role on dioxin formation, but not the chlorine content.[44]

The design of modern incinerators minimises PCDD/F formation by optimising the stability of the thermal process. To comply with the EU emission limit of 0.1 ng I-TEQ/m3 modern incinerators operate in conditions minimising dioxin formation and are equipped with pollution control devices which catch the low amounts produced. Recent information is showing for example that dioxin levels in populations near incinerators in Lisbon and Madeira have not risen since the plants began operating in 1999 and 2002 respectively.

Several studies have also shown that removing PVC from waste would not significantly reduce the quantity of dioxins emitted. The European Union Commission published in July 2000 a Green Paper on the Environmental Issues of PVC. "[45] The Commission states (page 27) that it has been suggested that the reduction of the chlorine content in the waste can contribute to the reduction of dioxin formation, even though the actual mechanism is not fully understood. The influence on the reduction is also expected to be a second or third order relationship. It is most likely that the main incineration parameters, such as the temperature and the oxygen concentration, have a major influence on the dioxin formation". The Green Paper states further that at the current levels of chlorine in municipal waste, there does not seem to be a direct quantitative relationship between chlorine content and dioxin formation.

A study commissioned by the European Commission on "Life Cycle Assessment of PVC and of principal competing materials" states that "Recent studies show that the presence of PVC has no significant effect on the amount of dioxins released through incineration of plastic waste."[46]

BASF – FILMS

http://worldaccount.basf.com/wa/EU~en_GB/Catalog/PlasticAdditivesEU/pi/BASF/range/sp_pe_films

Films
The majority of polyethylene (PE) is used in film. Typical applications in the packaging industry are food packaging, grocery sacks and stretch wrap films. Non-packaging applications are domestic trash can liners and in agricultural applications. All kind of polyethylenes are used in film. Low-density polyethylene (LDPE) is still dominant in the agriculture industry as well as in many packaging applications. Nonetheless linear low-density polyethylene (LLDPE) as well as high-density polyethylene (HDPE) are gaining market share due to favorable stiffness, toughness or impact and puncture resistance. For applications with the highest demands of film transparency it is important to ensure high productivity in combination with excellent film properties, optimized processing stability is required making superior stabilization essential to minimize gel formation and discoloration. To meet the requirements on LLDPE/HDPE blown and cast film grades, BASF offers synergistic solution of antioxidant blends which are tailored for either general or color-critical applications. For outdoor applications such as mulch films in the agricultural industry, where light and weather stability is required, BASF offers a broad range of hindered amine light stabilizers (HALS) and UV absorbers.