PET / PETE Polyester, Its advantages, and its Health issues

PET / PETE Bottles, Jars, Pots, PET Films,

for Food, Water & Beverage Packaging

Polyester, which are primary known for the production of synthetic fibers, are now used for many different applications. Nowadays, PET used as raw material for production of packaging, including food packaging, bottles for water & beverages, films and engineering plastics.

PET polyester used for those products are modified by adding co-monomers and additives which influence the properties of the co-polyesters, such as:

1. melting temperature,
2. high clarity,
3. crystallization rate,
4. neutral color,
5. low acetaldehyde during perform production,
6. second order transition temperature.

Modified resins for rigid packaging, in general, are of higher molecular weights than standard PET resins, the required viscosities as well as the lowest acetaldehyde levels are reached by solid state poly-condensation.

PET [Poly-Ethylene-Terephthalate] polyester manufacturing process:

Pure Terephthalic Acid or Dimethyl-Terephthalate and Ethylene glycol are used for esterification or trans-esterification and further poly-condensation to Poly-Ethylen-Terephthalate [PET]. Diols or Dicarbonic acids are added as co-monomers, they are built into the polyester chains to reduce the melting temperature and the crystallization rate of the so produced co-PET, this modification is necessary to achieve the required product quality for rigid packaging products, with lower temperature and longer resident time technology, gives many benefits, such as minimal reaction by-products, low acetaldehyde formation, excellent product quality, and greater energy efficiency, in the manufacturing process of PET, it uses Antimony-based catalyst [Sb₂O₃], but now has changed with heavy metal free catalyst and stabilizer system

Solid State Poly-condensation process:

Amorphorous PET chips are crystallized in crystallizers, then fed to a reactor where the solid state polycondensation process takes place, the principle of solid state polycondensation process involves high temperature treatment of poly-ethylene-terephthalate [PET] chips in an oxygen-free and moisture-free environment for sufficiently long resident time to achieve the desired molecular weight, the removal of reaction products and volatile impurities, such as volatile organic compound [VOC] acetaldehyde are carried out by diffusion to the PET chips surface and from there into a gas stream, purified and dried nitrogen [N₂] is used as an inert carrier gas.

Advantages of PET Bottles:

• High clarity and free of particles,
• High brilliance, excellent gloss, crystal clear, glass like,
• Un-breakable, breakage resistant / no fear of breaking, customer friendly, easy to dispense,
• Low weight, 90% lighter than glass bottles, easy to carry, saving in transportation cost,
• Non toxic,
• Good chemical resistance, such as acids, alkalis, alcohols, organic solvents, oils, and fats,
• No taste influence on the filled products, totally inert,
• Retain good aroma of the filled products,
• Good barrier properties,
• Good mechanical properties, customizing bottle designed and specification can be tailor made as required,
• Good chemical resistance, such as acids [fair to good], alkalis [poor to fair], alcohols [good], organic solvents [good], oils [good], and fats [good],
• Good form stability, bottle dimensional accuracy gives consistent filling point and brimful volumes, filling efficiency lines possible, bottles blow molding & bottle filling can be synchronized on one production line,
• Good printability, glued and heat shrink labeling possible,
• Can be recycled, eco-friendly.

PET has become the material of choice for bottled water & beverages because it is lightweight and breakage resistant, and PET has been extensively tested for safety, bottles made with PET are widely used for everything from water and fruit juice to soft drinks and even beer.

Advantages of PET-Film Packaging:

• Excellent transparency and gloss,
• High brilliance, excellent gloss, crystal clear, glass like,
• Low weight, 90% lighter than glass made, easy to carry, saving in transportation cost,
• Non toxic,
• Un-breakable, breakage resistant / no fear of breaking, customer friendly, easy to dispense,
• Suitable for food packaging including fats,
• Good chemical resistance, such as acids [fair to good], alkalis [poor to fair], alcohols [good], organic solvents [good], oils [good], and fats [good],
• Low water absorption,
• Good gas barrier / low gas permeability,
• Easy thermoform,
• Good mechanical properties,
• Good printability, glued and heat shrink labeling possible,
• Can be recycled, eco-friendly.

PET Bottles and Health issues:

PET packaging is cleared for safety in food and beverage packaging for single and repeated use, because it is suitable, convenient and recyclable, the U.S. Food and Drug Administration [FDA] has reviewed migration testing data and concluded the PET containers do not leach harmful amounts of substances into their contents under foreseeable conditions of use, all bottles that are re-used should always be properly cleaned, using soap and hot water and then dried thoroughly after that to prevent bacterial growth.

Antimony catalyst used in manufacturing PET:

Antimony trioxide [Sb₂O₃] is often used as a catalyst in the production of PET, metallic antimony [Sb / Stibium] is not used, the function of the catalysts are to ensure that a process happens fast enough, it is just because catalysts speed chemical reactions, to make it commercially practical, antimony was chosen based on its effectiveness as a catalyst; productivity and safety, a 1997 study showed that antimony trioxide has very low toxicity, the compound is relatively inert and does not participate in biological life, a report by the International Life Sciences Institute showed less than five parts per billion (<>

Refill use of PET bottle:

The PET bottle itself poses no danger when refilled. PET is an inert plastic and does not leach harmful materials into its contents, either when a beverage is stored closely, or when bottles are refilled and frozen, the PET containers have been safely used for 20 years and have undergone rigorous testing under FDA guidelines to ensure their safety as a food and beverage containers suitable for storage and reuse, opened bottles can contain bacteria, so that, all PET bottles should be washed with hot, soapy water and dried thoroughly prior to reuse.

Beverages stored and frozen in PET bottles:

It is not danger to freeze PET bottle with beverages content in it, no dioxins are leached from frozen PET bottles into bottle contents.

Leaving a filled PET bottle in a hot car:

The issue that PET bottles leach chemicals when heated in hot cars is not based on any science, and is unsubstantiated by any credible evidence.

PET Bottle leaches Phthalates, DEHA, or Bisphenol-A issues:

1. Phathalates: Poly-Ethylene-Terephthalate [PET / PETE] bottle does not contain plasticizer orthophthalates. PET bottle used terephthalates [different with orthophthalate] as raw material in its manufacturing.
2. DEHA [Di-Ethyl-Hexyl-Adipate]: PET bottles does not use additive substance Diethylhexyl-Adipate, PET bottle does not contain any carcinogenic elements, and DEHA itself is not classified as a carcinogen and has been cleared by the FDA for use to make other kind of plastics (not PET).
3. Bis-phenol A [BPA]: There is no connection between PET plastic and Bis-phenol A. PET does not contain BPA because BPA is not used in PET’s manufacturing, BPA is used in polycarbonate bottles [#7]. Bisphenol A itself belongs to a group of substances which have a hormone-like [oestrogen] effect, this substance may be contained in plastic objects including objects that come into contact with food, some examples are baby bottles [Polycarbonate baby feed bottles #7], beakers, plastic cutlery [knives, forks, spoons used fro eating] or the inner lining of cans.

Also Read:
Safely use of Plastic FoodPackaging
Safely use of Baby Feed Polycarbonate Bottle

Safely use of Plastic Food Packaging

There are seven type of plastic polymers used for food-drink packaging,

many of their additives as well as monomers impurities are harmful for health.

The plastic resin identification codes

Plastics play many important roles in life on earth, but the widespread use of plastics are also causing environmental problems, and harmful for health, chemicals leached from plastics used in cooking and food / drink storage are harmful to human health, the most disturbing of these are hormone disrupters, like Bisphenol A (BPA), which can stimulate the growth of cancer cells, exposure to BPA at a young age can cause genetic damage, the health risks of plastic are significantly amplified in children, whose immune and organ systems are developing and are more vulnerable, plastic should be used wisely, with caution and only when suitable alternatives do not exist or available.
Plastic packaging polymers (resins) which are safe for food and beverages are type No.1 (PET / PETE), No.2 (HDPE), No.4 (LDPE), No.5 (PP). which are not safe for foods and beverages are type No.3 (PVC), No.6 (Polystyrene), and No.7 (others / Polycarbonate).

Recycle of used plastic packaging :

Consumers have a way to identify the type of plastic in many products, especially food storage containers and packaging, the resin identification code in molded formed or imprinted on the bottom of plastic containers. This system of coding was developed in 1988 by the U.S.based Society of the Plastics Industry to facilitate the recycling of post-consumer plastics, it is voluntary for plastic manufacturers, but has become relatively standard on certain plastic products sold globally, unfortunately, as a matter of fact, many plastic products have not yet bearing the resin identification code.

platic polymer / resin identification codes imprinted

at the bottom of plastic bottles

Use of the resin identification codes:

1. For consumers, by knowing the resin identification code for particular plastic products, consumers can then inform themselves of the characteristics of the plastics and the risks of using that products.
2. For plastic recyclers, in the process of recycling, plastic packaging should be separated in groups based on their type of resins (polymers) and their colors,

Recycled plastic packaging are prohibited for re-packing foods and beverages, they are used for other purposes, use only genuine plastic polymers for foods, drinks, drugs / medicines, medicinal devices, and cosmetics.

Polymer chemical compounds can be classified into:

1. Natural polymers: shellac, amber.

2. Biopolymers: proteins, DNA, cellulose.

3. Synthetic polymers: plastics, silicones, nylon, polyacrylonitril.

Plastics are synthetic polymer products, the results polymerization (polycondensation) of the monomers depending on the type of plastics, monomers are nsaturated hydrocarbon chemical compounds, have a double bond between their two carbon atom (double bond chain), called Alkene or olefine, monomers for plastic manufacturing are ethylene, propylene, vinyl-chloride, styrene etc.

Plastic polymers can be divided into two groups:

Polyolefins: polymerization of alkene or olefine,

1. HDPE (High Density Polyethylene) – Recycle code No.2: HDPE is flexible, more rigid than LDPE, good impact strength and stress crack reesistence, good chemical resistance, good vapor barrier. Common uses: plastic bottles and jars for drinking water, foods, milks, juices, cosmetics, detergents and shampoo bottles.
2. PVC (Polyvinyl Chloride) – Recycle code No.3: PVC is flexible to rigid, good for coating, fair water vapor barrier but good oxygen barrier, good chemical resistance, good impact and some stress crack resistance, poor recycling due to chloride residues. Common uses: clear foods and non foods packaging (cling-wrap), squeeze bottles, shampoo bottles, cooking oils, peanut butter jars, medical tubing (medical devices), detergents, glass cleaner bottles, shower curtains, numerous construction products (wire insulations, pipes, sidings). Leaches di(2-ethylhexyl) phthalate (DEHP) or butyl benzyl phthalate (BBzP), depending on which is used as the plasticizer or softener in the manufacturing. PVC has been described as one of the most hazardous consumer products ever created
3. LDPE (Low Density Polyethylene) – Recycle code No.4: LDPE is very flexible, natural milky color, translucent with high impact strength, good chemical resistance, good water vapor and alcohol barrier properties, poor gas barrier, hood stress crack and impact resistance. Common uses: squeezable bottles for honey, mustard, for bread and food bags, used in grocery store, dry cleaning, most plastic wraps.
4. PP (Polypropylene) – Recycle code No.5: PP is rigid, solid, durable in container or cap forms, opaque, natural grayish yellow in natural form, excellent stress crack and impact resistance, PP botlles and jars have excellent moisture barrier, good oil and alcohol barriers, poor gas barrier properties, good chemical resistance. Common uses: plastic containers for ketchups, yogurts, syrup bottles, drinking straws, baby bottles, margarines tubs, medicines.
5. PS (Polystyrene) – Recycle code No.6: PS is transparent, rigid and glasslike polymer, light and heat stable, biologically inert and non-toxic, good resistance to inorganic chemicals, PS containers have good impact and stress resistance, poor barrier properties. Common uses: Styrofoam containers, food plates, take-out food containers, disposable cups and bowls, packaging for CDs (compact disc cases), egg cartons, plastic cutlery. Leaches styrene, which is an endocrine disruptor mimicking the female hormone estrogen, and thus has the potential to cause reproductive and developmental problems.
6. Other (miscellaneous classification) - Recycle No.7: it includes:

• PC (polycarbonate), a dangerous plastic, the new, safer, Common uses of PC bottles: plastic bottles for squeezable ketchups and syrups, juices, used in most plastic baby feed bottles, clear plastic sippy cups, drinking water bottles, large water storage containers, metal food can liners, compact discs, cell phones, computers. Leaches Bisphenol-A an hormone (endocrine) disrupters. Plastic bottles and plastic containers from this group are not easily recyclable
• Bioplastics: Biodegradable bio-based plastics (Plastarch material – PSM) & Polylactic acid or polylactide (PLA) made from renewable resources such as corn and potato starch, and sugar cane, the new safer plastic products.
• PTFE (Polytetrafluoroethylene), known as Teflon.
• Acrylonitrile styrene (AS) or styrene acrylonitrile (SAN), and Acrylonitrile butadiene styrene (ABS). Both AS/SAN and ABS are higher quality plastics with increased strength, rigidity, toughness and temperature and chemical resistance. AS/SAN is used in mixing bowls, thermos casing, dishes, cutlery, coffee filters, toothbrushes, outer covers (printers, calculators, lamps), battery housing. The incorporation of butadiene during the manufacture of AS/SAN, produces ABS, which is an even tougher plastic. ABS is used in LEGO toys, pipes, golf club heads, automotive parts, protective head gear.
  

Polyester: polymerization of esters

1. PET / PETE (Polyethelene Terephthalate) – Recycle code No.1; PET or PETE is semi-rigid to rigid depending on container’s wall thickness, good to fair chemical barrier, not good for strong acids and bases (alkali), good solvent and alcohol barrier, good gas and fair moisture barrier, good moldability. PET / PETE bottles and jars have good stress crack and impact at room temperature. Common uses: bottles for drinking waters, soft drinks, sodas, beers, juices, foods, salad dressings, edible oils, peanut butters, cereal box liners, mouthwashes, lotions, liquid soaps / detergents, cleaning agent containers. Leaches Antimony trioxide.
2. PBT (Polybutylene Terephthalate) – Recycle code No.1: good chemical resistance, clear color, resistance to water, weak acids and bases at room temperature.
3. Polyester fabrics.
4. Polyester fibers.

Harmful chemical compounds in the plastic products:

In the process of polymerization (poly-condensation) there are possibilities of some monomers which are not bound into polymer molecules (macro-molecules), so that they remain as monomer-free compounds in the plastic products.
There are three compounds in plastic products:

1. Polymer compounds: poly-olefins, or polyesters. International Agency for research on Cancer (IARC) studies on carcinogenicity of plastic polymers on animals indicate that plastic polymers are not inherently carcinogenic or genetotoxic. Plastic Polymers are biologically inert due to high molecular weight.
2. Additives (chemicals added to improve the nature of plastics themselves.
3. Monomers impurities.

Many additive chemical compounds used for plastic manufacturing are harmful for human health, they can leach into foods, drinks etc.

Additives for plastics manufacturing are classified based on their functions:
Additives are not part of the polymers matrix, they may migrate out of the plastic surface, the extent of migration is usually enhanced by temperature, additives are usually made up of small molecules which may be absorbed into the human body, some additives are very toxic, lead (Pb) and cadmium (Cd) containing stabilizers have potential adverse human, and eco-toxicological effect, now they are currently being phased out and replaced by stearate and oleate salt of Barium (Ba), Zinc (Zn), Calcium (Ca) system. Lubricants as plastic additives generally do not pose human hazard unless they contain heavy metals. (see Lead-stearate as lubricant). Plasticizers phathalate and adipates as plastic additives are commonly used in PVC manufacturing, they can easily off-gas and migrate into fatty foods when foods are wrapped in PVC, high dosage of phthalates and adipates may cause testicular atrophy, decrease spermatogenesis and lower fertility.

1. Stabilizer:

· Lead compound, compound Lead / Plumbum (Pb): lead-oxides, lead-sulphates, lead-phosphates.

· Cadmium compound (Cd).

· Metal-soap-compound: Zn, Ca/Zn, Ba/Zn, Ba/Cd- stearates and oleate.

· Organic tin compounds (Zn / tin), such as dimethyl-tin-thioglycolate.

2. Palsticizers:

· Phathalates: Diethylhexylphthalate (DEHP), Dioctylphthalate (DOP)

· Adipates: Diethylhexyladipate (DEHA),

· Bisphenol (BPA), used in Polycarbonate baby bottles.

3. Lubricants:

· Lead-stearate,

· Stearic-acid (waxes),

· Mineral-oil.

4. Catalysts:

· Hydrogen peroxide (H₂O₂)

· Ethyl-chloroformate,

· Methylethyl-ketone peroxide,

· Antimony-based catalyst used in the manufacturing of PET bottles.

5. Others additives:

· Pigments: should be food grade (FDC).

· Fillers: talc, titanium-dioxide (TiO₂).

· Bacteriostatics.

· UV radiation absorbers.

· Antistatic agents

· Surfactants.

Additives should be considered carefully, some of them are very toxic, consideration must be made to :

• · Length of food exposure,
• · rate of additives and residues migration into foods,
• · possibility of accumulation.
• 
  

Monomers impurities: ethylene, vinyl-chloride, propylene, styrene.

Some plastic monomers (residue / impurities in plastic manufacturing – during polymerization process) may pose hazards, in some plastics, residues are negligible, but in others they are significant, especially if the molecular weight of the plastic polymers are small, most monomers are not appreciably absorbed through skin, but can be absorbed very well by lung and gastrointestinal tract. Vinyl-chloride monomer (VCM) causes liver cancer, also causes skin and lung tumor, depression of central nerve system (CNS) at dosage of 8000-10.000 ppm. Ethylene and propylene monomers are not genetotoxic. Styrene are strongly genetotoxic when metabolized to styrene-oxide, styrene may also be carcinogenic to human.

Various plastic containers for drinking water sold in the market:

· No.1 (PET / PETE) for drinking water packaged in plastic bottles of 600 ml – 1000 ml.

· No.5 (PP) for drinking water packaged in plastic glass or plastic cup of 250 ml.

· No.7 (Other) for drinking water packaged in plastic gallon container of 20 liters

· No.2 (HDPE) for bottles and gallon plastic caps.

How to use safely plastic food-drink containers?

• Drinking water, try and avoid plastic bottles, use glass bottles or stailess steel bottles, if use plastic bottles made from #1(PET / PETE) or #2 (HDPE) plastic try not to reuse them, and consume the contents as soon as possible because leaching of antimony increases with time.
• Do not use plastic dishes and utensils for meals, as alternatives use glass, ceramic, wood, stainless steel, and lacquer ware.
• Do not heat foods in plastic containers, especially in the microwave oven, which can cause the plastic to degrade and leach chemicals faster, leaching increases when plastic comes into contact with oily or fatty foods, or when the plastic is scratched, worn, cracked, or sticky.
• Do not use PC (polycarbonate) baby bottles, try to use glass, polyethylene, or polypropylene, check the bottle to be sure of the type of plastic code it contains. for baby bottle nipples, try and use silicone which does not leach the carcinogenic nitrosamines that can be found in latex, if has to use PC (polycarbonate) bottles, do not heat the foods and drinks in the bottle, heat them in a separate containers and then transfer them to the bottle once it is warm enough for the child to eat or drink, if the PC plastic bottles are showing signs of wears or scratched, cloudy, do not use but discard the container, replace with the new one.
• Use sippy cups made of stainless steel, or made of polypropylene or polyethylene.
• Use plastic wraps with caution, especially in the microwave, and try to keep the plastic from touching the food, as safer alternatives are using wax paper.

Stainless steel and glass food storage containers are the best for use.

Continued with Related Articles:

· PET / PETE Bottle, its advantages, and its Health issues

· Safely use of Polycarbonate Baby Feed Bottles

· Safely use of Polystyrene Food Plates

. Bioplastics

Green Mosquito Repellents, Repel the Mosquitoes naturally.

A Community Health

How to Control Mosquito

Part 7: Green Mosquito Repellents, Repel Mosquito naturally !

Environment friendly – Eco friendly :
The environmental friendly (eco-friendly) and biodegradable natural insecticides derive from herbs and plants origin are alternative green mosquito repellent. Repellents of plant origin have been used for medicinal purposes for a long time because they do not cause hazards of toxicity to human beings and are easily biodegradable, when compared with other synthetic chemical compounds, natural products are far safer for human beings use.
The chemical contents extracted from herb and plant materials can be used as larvacides, insecticides, and repellents, herb and plant products have been used in many parts of the world for killing or repelling mosquitoes either as extracts, oils or as the whole herbs or plants, many natural products have been tested for repellent activity against mosquitoes, for examples: Ocimum species, Eucalyptus species and Lemon grass.

In addition to using mosquito repelling plants, we want to consider some other factors that can help keep mosquitoes away. Mosquitoes find their host by following carbon dioxide, lactic acid and other components that human beings breath out, mosquitoes key in on carbon dioxide signatures of warm-blooded creatures, humans have a CO2 signature of their own which mosquitoes love them best, blood is close to the surface of the skin. Citronella oil (contains Citronellal) sprayed and misted into the air confuses the mosquitoes because it interferes with their ability to detect CO2. Many outdoors-people have noticed that mosquitoes have a greater attraction to people that have been eating processed foods, sugary foods, on the other hand, mosquitoes less attracted to people eating more of a natural diet such as whole grains, fruits, and vegetables, the processed food diet may make our body odor and blood chemistry more attractive to mosquitoes, beside that, diets high in garlic and onions have been noted to help reduce the attraction of mosquitoes.
We must realize that natural does not always mean safe, because many people are sensitive to plant oils, some of the natural insect repellents are toxic, therefore, although natural repellents provide an alternative to synthetic chemicals repellents, please be careful to follow the manufacturer's instructions when using natural insect repellent products.

Please be noted that different species of mosquitoes are
repelled by and attracted to different things.

Mosquito Repellent Herbs and Plants:

There are a variety of both wild and cultivated herbs and plants that repel mosquitoes, plant-based mosquito repellents are especially useful for people who spend a great deal of time in the wilderness. There are many attractive garden herbs and plants that repel mosquitoes, planting these herbs and plants that repel mosquitoes is a great choice for our house, these attractive herbs and plants do not just enhance the landscape, but we can have a pretty ornaments that also drive mosquitoes away, moreover, it is not only earth-friendly way of repelling those insects, it will add beauty to your gardens, and will not harm our health.

It is important to note that there are many chemical compounds found in the herbs and plants that do repel the mosquitoes, those chemical compounds need to be released from the herbs and plants to increase the mosquito-repelling qualities, depending on the species of herbs and plants themselves, they can be released by either crushing, drying, extracting or steam distillation of the herbs and plants into extracts or oils or alcohol bases that can be applied to skin, clothing, or living rooms, there are also herbs and plants that are best used as smokes, which releases the volatile organic compounds in a smokes.

There two different opinions on Mosquito repellent herbs and plants:
1. First opinion: people who are sure that Just standing near living plants that repel mosquitoes is often not effective, the herbs and plants must be crushed to release the aroma, otherwise mosquitoes can't smell them.
2. Second opinion: people who are sure that those herbs and plants can repel mosquitoes effectively, due to the characteristic aromas they have which mosquitoes don’t like.
Nevertheless, we appreciate, those are free opinions, based on their experiences. It is better to try than do nothing (No Action, Talk Only).

Mosquito Repellent Herbs:

Zodia / Evodia suaveolens :

Zodia or Evodia suaveolens (Rutaceae) is a genuine Indonesia herb, originally from Papua Island. Zodia can repels mosquito, either indoor or outdoor, this is due to its characteristic aroma containing evodiamine and rutaecarpine which mosquitoes don’t like them. It should be noted that Zodia does not kill the mosquitoes, but only gets rid of or repel them from surroundings, Zodia is used besides as mosquito repellent herb, it is also used as decorative plant in house garden. The Papua people usually rub Zodia’s leaves on their skin when they are going to the forest to prevent mosquitoes’ bites, they also believe that Zodia can repel mosquitoes from its surroundings, when there is wind blowing across the herbs, their leaves scratched each other, producing aromatic organic compounds which caused the mosquitoes go away, its scents (stink / unpleasant odor) are totally unacceptable to mosquitoes, so many people now cultivate and place the Zodia herbs at home indoors as well as in front of the doors and the windows (outdoors)

Evodiamine

Gas Chromatographic result of the Oil produced from the leaves of Zodia contains 46% Linalol and 13,26% alpha-Pinene, which area well known as mosquito repellent. Examinations to Aedes aegypti mosquito (mosquito causing dengue desease) indicate that the arms which have been rubbed with leaves of zodia is protected against the mosquito attack during 6 hours compared to arms which are not rubbed. The ability of zodia to repel the mosquito is equal to 70%, more over, the skin bitted by the mosquitoes will faster relief when rubbing with Zodia leaves.

Lavender / Lavandula officinalis

Lavender or Lavandula angustifolia - Mill. Failia Labiatae,
The essential oil obtained from the flowers is very good scented, has a very wide range of applications, it can be used as an insect repellent, the aromatic leaves and flowers are used as an insect repellent, to deliver an aromatic sweet smell to house rooms and to repel mosquitoes.

Citronella Grass

Citronella Grass (Cymbopogon nardus) which grows in tropical regions, is the most popular cultivated plant used for repelling mosquitoes, Citronella oil obtained from Citronella grass contains Citronellal that has insect repellent properties, research shows high repellent effectiveness against mosquitoes. Citronella oil is the primary ingredient in most natural insect repellents, products applied to the skin are most effective.

Citronellal

Ocimum basilicum

Sweet Basil or Ocimum basilicum (Lamiaceae) is an effective insect repellent, it is a good plant to grow in house, where it repels insects, essential oil obtained from the whole plant when applied to the skin it makes a good mosquito repellent.

Rosemary / Rosmarinus officinalis

Rosemary or Rosmarinus officinalis (Labiatae) belongs to mint family. Its native habitat is the area around the Mediterranean Sea and Portugal, now cultivated in many countries, its leaves are long and skinny like pine needles. Rosemary flowers which are violet in color, bloom briefly in spring, Rosemary is a great natural mosquito repellant herb, its essential oil contains eucalyptol (cineole) is considered to have potential antibacterial effects, and has mosquito repellent properties.

Additional cultivated plants that repel mosquitoes:

Peppermint (Mentha piperita)
Marigolds (Tagetes spp.)
Lemon balm (Melissa officinalis)
Garlic (Allium sativum)
Clove (Syzygium aromaticum)
Eucalyptus (Eucalyptus spp.)
Tea tree (Melaleuca alternifolia)

Related Articles:

Studying mosquito life cycle to best control of them.

Can we paralyze the mosquito battery sensors?

Do Insecticides & Pesticides no harm to human beings?

How to choose more user friendly Insecticides?

Which Mosquito Repellents are safe for use?

Natural Sources Mosquito Repellents.

Green Goes with Everything: Simple Steps to a Healthier Life and a Cleaner Planet

Natural Sources Mosquito Repellents.

A Community Health

How to Control Mosquito

Part 6: Natural source of Mosquito Repellents.

Thousands of plants have been tested as potential sources of insect repellents. None of the plant-derived chemicals tested to date demonstrate the broad effectiveness and duration of DEET, but a few show repellent activity. Plants whose essential oils have been reported to have repellent activity include citronella, cedar, verbena, pennyroyal, geranium, lavender, pine, cajuput, cinnamon, rosemary, basil, thyme, allspice, garlic, and peppermint. Unlike synthetic insect repellents, plant-derived repellents have been relatively poorly studied. When tested, most of these essential oils tended to give short-lasting protection, usually less than 2 hours. Readily available plant-derived insect repellents are listed in.
On the Contrary: if someone consumes bananas, the mosquitoes like to bite. Stop eating bananas for the summer and the mosquitoes will be much less interested.

Mosquito Repellents from natural sources :
There are many naturally occurring pesticides / insecticides which can be used as a mosquito repellent, and some of these are:
Achillea alpina, alpha-terpinene, carvacol, Castor Oil, Catnip Oil, Cedar Oil, Celery Extract, Citronella Oil, Clove Oil, Eucalyptus Oil (Cineole), Cajuput Oil (Cineole), Fenel Oil, Garlic, Leongrass Oil, Geranium Oil, Lemon eucalyptus (p-methane-3,8-diol), Nee Oil, Peppermint Oil, Pennyroyal, Rosemary, Tea Tree Oil, Thyme.

Plant derived Repellents :

Lemon Eucalyptus Oil:
Lemon Eucalyptus Oil contains p-menthane, 3,8-diol / PMD, was the best non-DEET mosquito repellent, although the people criticized its odor. Lemon eucalyptus plant extract is registered in Canada for use as an insect repellent. It may protect from mosquitoes’ bites for up to two hours, but is not recommended for use on children under the age of three. Lemon Eucalyptus Oil / PMD-based repellents show low toxicity, but care must be taken to keep them out of the eyes because PMD can cause significant eye irritation.
Comparison : Lemon Eucalyptus Repellent provided 120.1 minutes of mosquito protection, more than a repellent with a low concentration of the chemical DEET, 4.75% DEET provided 88.4 minutes of protection and 23.8% DEET provided 301.5 minutes of protection.

Citronella :
Citronella is registered with the EPA (The United States Environment Protection Agency) as an insect repellent since 1948, considers as a non toxic biopesticide, has been verified by research, including effectiveness in repelling Aedes aegypti (yellow fever mosquito).
Citronella oil has a lemony scent and was originally extracted from the grass plant Cymbopogon nardus, originally extracted from the leaves and stems of different species of Cymbopogon, the oil is used extensively as a source of perfumery chemicals such as citronellal, citronellal and geraniol. These chemicals find extensive use in soap, perfumery, cosmetic and flavouring industries throughout the world.
The US Environmental Protection Agency (EPA) states that citronella oil has little or no toxicity when used as a topical insect repellent, with no reports of adverse effects of concern over a 60 year period. Because some products are applied to human skin, EPA requires proper precautionary labeling to help assure safe use, because citronella may irritate skin and cause dermatitis in certain individuals. If used according to label instructions in the US, citronella is not expected to pose health risks to people, including children and other sensitive populations. The US Food & Drug Administration consider citronella oil as generally recognized as safe (GRAS).

Studies show that citronella can be an effective repellent, but it provides shorter complete protection time than most DEET-based products, to be continually effective, frequent reapplication of the repellent to the skin every 30-60 minutes should be done. Citronella oil also shows has strong antifungal properties, and research indicates that citronella oil is an effective repellent for body louse and head louse, Citronella may irritate skin and cause dermatitis in certain individuals. It should not be used on the skin of young children (under 3 years old).

Citronella oil is classified in trade into two chemotypes:
1. Ceylon type: obtained from Cymbopogon nardus Rendle, consists of citronellal (5-15%), geraniol (18-20%), limonene (9-11%), methyl isoeugenol (7-11%), citronellol (6-8%). In Europe, Ceylon type citronella oil is placed on the category 3 list, with some safety concern regarding methyl isoeugenol.
2. Java type: obtained from Cymbopogon winterianus Jowitt, consists of citronellal (32-45%), geraniol (11-13%), limonene (1-4%), geranyl acetate (3-8%). The higher proportions of geraniol and citronellal in the Java type make it a better source for perfumery derivatives.

Note : Citronella oil from Cymbopogon species should not be confused with other similar lemony oils from Corymbia citriodora and Pelargonium citrosum.
1. Citronella soap is a product that started in the Bahamas and Belize. The soaps are made with olive oil for moisture and great lather, Aloe Vera to soothe the skin, and citronella oil to repel mosquitoes. For high intensity protection you can burn citronella incense. Mosquitoes avoid citronella and they hate the smoke.
2. Citronella essential oil (Java Citronella) is considered to be the highest quality citronella on the market. The best quality is steam distilled from the grass giving it a fresh, sweet woody aroma. It blends well with geranium, cedar wood and other citrus oils. It is 100 percent pure essential oil, no additives, no dilutants, no adulteration, just safe mosquito repellent.

Citronella Candles :
A well-known natural mosquito repellent, effective in protecting from mosquitoes’ bites at concentration of 3% citronella oil in candles, human beeings who are positioned near a citronella candles had 42.3% less bites, citronella candles shouldn't be used as a stand-alone repellent, they may help in combination with topical repellents.

Neem oil :
Neem oil is a vegetable oil pressed from the fruits and seeds of tropical Neem tree (Azadirachta indica), an evergreen tree which is endemic to the Indian subcontinent and has been introduced to many other areas in the tropics.
Neem oil is generally light to dark brown, bitter and has a rather strong odor that is said to combine the odors of peanut and garlic. It comprises mainly triglycerides and large amounts of triterpenoid compounds, which are responsible for the bitter taste.
Neem oil also contains steroids: campesterol, beta-sitosterol, stigmasterol and a triterpenoids of which Azadirachtin is the most well known, it has insecticidal properties, the Azadirachtin content of neem oil varies from 300 ppm to over 2500 ppm depending on the extraction technology and quality of the neem seeds crushed.

Geranium oil :
Mix: 20 drops Eucalyptus oil
20 drops Cedarwood oil
10 drops Tea Tree oil
10 drops Geranium oil
2 oz. Jojoba oil as carrier oil.
Apply to skin as needed avoiding the eye area.
Another product: Bite Blocker, available as a spray or lotion, contains the oils of Geranium oil, Soybean oil and Coconut oil, 30 minutes of complete protection from mosquito bites.

Fenel Oil :
An aerosol spray mosquito repellent containing 5% fennel oil was 84% effective after 90 minutes,
A repellent cream with 8% fennel oil was 70% effective after 90 minutes.

Thyme Oil :
Thyme oil contains carvacrol and alpha-terpinene, found to have significantly greater repellency than a commercial DEET repellent, but don't try to make a thyme oil repellent at home, because it is too irritating and strong-smelling to be used at effective concentrations of above 25%.

Clove oil :
Undiluted topical Clove oil is active against mosquitoes, but same like thyme oil, clove oil should not be applied undiluted to skin as a homemade repellent.

Soybean oil :
Soybean oil two per cent can keep human beings from mosquito bites from one to four hours, It has low toxicity, non-irritating. Consequently, it may also be considered as an alternative to DEET.

Garlic :
Another popular theory is that ingesting garlic can provide protection against mosquitoes.


Celery extract :
Celery extract actives against a wide range of mosquito species comparable to a 25% DEET formula, and Celery extract did not irritate the skin or cause a burning sensation

Catnip:
Catnip or Nepeta cataria is a perennial herb belonging to the mint family and grows wild in most parts of the United States, although it also is cultivated for commercial use. Catnip is native to Europe and was introduced to this country in the late 18th century. It is primarily known for the stimulating effect it has on cats, although some people use the leaves in tea, as a meat tenderizer and even as a folk treatment for fevers, colds, cramps and migraines.

Catnip contains Nepetalactone, a bicyclic terpenoid, isolated by steam distillation, Nepetalactone is the essential oil component in catnip that gives the plant its characteristic odor, repels mosquitoes 10 times more effectively than DEET (Diethyl-m-toluamide), Nepetalactone is the compound used in most commercial insect repellents. Catnip works against all types of mosquitoes, Nepetalactone is safe for people.
Why catnip repels mosquitoes is still a mystery, it might simply be acting as an irritant or the mosquitoes don’t like the smell.

Vitamin B-1:
Vitamin B1 is often taken to help repel mosquitoes, takes one 100 mg of Vitamin B-1 (Thiamine Hydrochloride) tablet a day. The odor of the tablet comes out through body skin, repels the mosquitoes.

Picaridine / Icaridin / Bayrepel :

Picaridine or hydroxyethyl isobutyl piperidine carboxylate is derives from Pepper, a synthetic chemical compound, picaridine is nearly odorless, does not cause skin irritation, it has been registered with the U.S. Environmental Protection Agency (EPA), which means that the materials have been reviewed and approved for effectiveness and human safety, and recommended by the Centers for Disease Control and Prevention (CDC) for mosquitoes that may carry the West Nile virus.

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