 | ||
| Welcome to world of PLASTICS!!! Look around you, how many things do you see made from plastic? You will realize that plastics are everywhere. There are numerous plastics items such as: toys, pens, food or drink containers and plumbing pipes.
What are Plastics?
Plastics are any synthetic or semi-synthetic organic
polymer, which means that they are artificial or manufactured. So, synthetic materials are made of building blocks that are put together. Plastics are made of carbon. The main material used in the production of man-made plastics is oil(petroleum) and natural gas, but other natural materials like cellulose also can be also used to made plastics. Plastics are large carbon-containing compounds, called polymers which are composed of repeating units of shorter-carbon containing compounds, called monomers.
Plastics are grouped into two main polymer categories:
80% of the plastics produced are thermoplastics while Polyethylene, Polyvinylchloride(PVC), Polypropylene and Polystyrene are among the most commonly used thermoplastics (70%).
6 Main types of plastics:
Common uses: soft drink bottles, cooking oil bottles, peanut butter jars, products containing essential oils, some fruit juices, alcohol beverage bottles, space blankets.
Common uses: dry-cleaning bags, produce bags, trash can liners, food storage containers, bread bags, squeezable containers, six pack soda can rings, food storage.
Common uses: milk jugs, distilled water, large vinegar bottles, grocery bags, liquid laundry and dish detergent, fabric softener, motor oil, antifreeze, bleach and lotion.
Common uses: bottle caps, drinking straws, hinged containers, battery cases, dairy tubs (e.g. sour cream, cottage cheese), cereal box liners.
Common uses: chemical spray bottles, pipes, electrical wire insulation, clothing, bags, upholstery, tubing, flooring, waterbeds, pool toys, bottles.
Common uses: bottle caps, drinking straws, yogurt cups, clear carryout containers, vitamin bottles, fast food, spoons, knives and forks, hot cups, meat and produce trays, egg cartons, food containers.
The chemistry behind plastics:
All plastics are polymers, but not all polymers are plastics. Plastics are formed by a process called polymerization. Polymerization occurs when individual monomers bond together. Identical monomers that combine together form homopolymers while different monomers that combine together form copolymers. Most plastic are usually created with several types of plastics, so they will not break down.
The properties of a plastic are determined by:
The monomers that can be found in plastics include organic compound like ehylene, propylene, styrene, phenol, formaldehyde, ethylene glycol, vinyl chloride and acetonitrile.
Due to the different combination of monomers, different kind of plastics with different chemical properties can be produced.
There are 2 ways which monomers can bond together to form polymers of plastics.
Two small molecules, monomers bind with the loss of a smaller molecule, usually water, alcohol or acid. As in the above picture, both monomer #1 and #2 have hydroxyl groups (OH) and hydrogen group (H). When the two monomers come together, one monomer lose a hydrogen while the other lose a hydroxyl group. The hydrogen and hydroxyl form water (H2O), and the remaining electrons form a covalent chemical bond between the monomers. The resulting compound is the basic subunit of copolymers #1 and #2.
Addition reactions involve rearranging electrons of the double bonds within a monomer to form single bonds with other molecules. The two molecules then formed polymer and the process repeated until polymer chains are formed. The various polymer chains can interact and cross-link by forming strong or weak bonds between monomers contribute to the physical properties of plastics (soft/hard, stretchy/rigid, clear/opaque, chemically inert).
Today most plastics are made from petrochemicals(oil and natural gas). Oil is a carbon rich raw material.
How Plastics formed?
The general way of plastics formed
1. Crude oil and natural gas are refined into ethane, propane or other petrochemical products. As in above figure, ethane undergoes cracking process into ethylene under high temperature furnaces. Ethylene is a small hydrocarbon consisting 4 hydrogen atoms and 2 carbon atoms. Various ethylene is chemically processed to make hydrocarbon monomers or carbon monomers used in plastics.
2. The ethylenes carry out polymerization reactions. The reaction produce polymer resins. Resin is the mass of polymers and usually in the form of powder or tiny granules.
3. Resin is added with plasticizers, dyes and flame-retardant chemicals. The polymer is melted at first and cooled after that. The final polymer resins are formed usually in the forms of pellets. Finally, the polymer resins are processed into final plastic products by the main three processes, extrusion, injection and blow molding.
In our daily life now, it is almost impossible to live without plastics. Yes, plastics are very convenient to use because of their malleability and plasticity. They can be easily moulded by heating. But, did you know plastics take about 300 years to decay? Did you know almost a billion tons of plastics have been discarded since the 1950s? So, what happens to the plastic tossed out in the garbage? Lets us take the initiative by reducing the usage of plastics, only with that we perhaps can reduce and stop the harm to our planet, and in turn, benefit to ourselves. "Say No To Plastic Bags" please!
|
What's on your face?
Take a deep breath before you continue reading this post.
︳︳
︳
︳
︳
︳
Men also put make up on their faces?! Make up
for Halloween I think. (Pictures are taken from internet.)
From those
pictures above, make-ups can totally change a person's appearance, not only for
women but also men. Why women love to put make-ups on their faces? The reasons
are:
1.
They want fairer, smoother and younger skin by covering the dark
spots, dark circles, wrinkles, freckles, fine lines on their faces.
2. Make-ups make
a woman seem more attractive, charming, like-able, competent,
trustworthy and glamorous.
3. Women
can gain
self-confidence from their make-ups, for example, putting on blushes and
lipsticks makes a woman look healthier and sexier and eyeliners make a woman’s eyes stand
out more.
4. Make-ups will
protect their skins from the ravages of weather, central
heating and air conditioning, petrol fumes, etc.
5. Women are
just enjoying the fun applying make-ups on
their faces and sharing the experiences between friends.
-------------------------------------------------------------------------------------------------
Actually what do we know about cosmetics? Let
me do a simple introduction about cosmetics.
Cosmetics are chemical substances or mixture intended to be placed
in contact with the external
parts of the human body or with the teeth and the
mucous membranes of the oral cavity to clean
them or used to enhance or protect
the appearance or correct odour of the human body.
The term 'COSMETICS' covers a wide variety of products, including skin-care creams,
lotions,
powders, perfumes, lipsticks, fingernail and toe nail polish, eye and
facial makeup, permanent
waves, coloured contact lenses, hair dyes, hair sprays
and gels, moisturizers, shampoos,
deodorants and toothpastes, hand sanitizer,
baby products, bath oils, bubble baths, bath salts,
butters and many other
types of products.
Cosmetics bring us a lot
of benefits but have you ever wonder about the ugly side of cosmetics? Have you ever thought about what was in your
cosmetic's products? Are those chemical substances safe for humans’ bodies? Do
you find it hard to read all the ingredients in your cosmetics? Unfortunately
many cosmetics and beauty products are filled with harmful chemicals. One
philosophy … is not to put
anything on the face that you wouldn't eat. If
you wouldn't put it on your plate, then don’t put it on your face! This
is critical because the face absorbs material just as if you had eaten it. So,
if you would not put a spoon in your moisturizer jar and eat it, or use it as
an ingredient in a dish you would serve to your family, then you should not put
it on your face. Chemicals that you put in your mouth are absorbed into your
blood and reach your skin where they are deposited. When you put these
chemicals on your skin, they are absorbed by your skin cells into the blood,
and therefore into the body. Furthermore, some chemicals can enter skin cells
immediately, creating visible deposits (age spots/blemishes), and can worsen
the skin conditions you are trying to improve.
Do you have any idea what's in your shaving cream? Or perfume? When it comes to
beauty products, the effects of the ingredients they contain can be more than
just skin deep. The cosmetics industry uses thousands of synthetic chemicals in
its products, in everything from lipstick and lotion to shampoo and shaving
cream.
Many of these substances are also used in industrial manufacturing processes to clean industrial equipment, stabilize pesticides and grease gears. And we can all agree that an ingredient that effectively scours a garage floor may not be the best choice for a facial cleanser.
Many of these substances are also used in industrial manufacturing processes to clean industrial equipment, stabilize pesticides and grease gears. And we can all agree that an ingredient that effectively scours a garage floor may not be the best choice for a facial cleanser.
Following are some of the chemicals commonly found in cosmetics and what they do to us. This blog post might take some time to finish reading but please do take your time to read because it is closely related to our health especially girls who love to put on make-up. If you are a man who is reading this blog post, you could share to your girlfriends.
1.
BHA and BHT
Used
mainly in moisturizers and makeup as preservatives. The
oxidative characteristics and/or metabolites of BHA and BHT may contribute to
carcinogenicity or tumorigenicity; however the same reactions may combat
oxidative stress. There is evidence that certain persons may have difficulty
metabolizing BHA and BHT, resulting in health and behaviour changes.
2. Coal tar dyes
P-phenylenediamine
and colours listed as "CI" followed by five digits.
P-phenylenediamine is used in some hair dyes; other colours are used in a
variety of cosmetics. Potential to cause cancer and may be contaminated with
heavy metals toxic to the brain.
3. DEA-related ingredients
Used
in some creamy and foaming products, such as moisturizers and shampoos. Can
react to form nitrosamines, which may cause cancer. Harmful to fish and other
wildlife.
4. Dibutyl phthalate
Used
as a plasticizer in some nail care products. Suspected endocrine disrupter and
reproductive toxicant. Harmful to fish and other wildlife.
5. Formaldehyde-releasing preservatives
Used
in a variety of cosmetics. Slowly release small amounts of formaldehyde, which
causes cancer.
6. Paraben, methylparaben, butylparaben and
propylparaben
Used
in a variety of cosmetics as preservatives. Suspected endocrine disrupters and
may interfere with male reproductive functions. Parabens are
a group of compounds widely used as an antifungal agent, preservative and
antimicrobial in creams, lotions, ointments and other cosmetics, including
underarm deodorants. They are absorbed through the skin and have been
identified in biopsy samples from breast tumors.
7. Petrolatum
Used
in some hair products for shine and as a moisture barrier in some lip balms,
lip sticks and moisturizers. Can be contaminated with poly-cyclic aromatic
hydrocarbons, which may cause cancer.
8. Siloxanes
Used
in a variety of cosmetics to soften, smooth and moisten. Suspected endocrine
disrupter and reproductive toxicant (cyclotetrasiloxane). Harmful to fish and
other wildlife.
9. Sodium
laureth sulphate
Used
in some foaming cosmetics, such as shampoos, cleansers and bubble bath. Can be
contaminated with 1,4-dioxane, which may cause cancer.
10. Triclosan
Used
in some antibacterial cosmetics, such as toothpastes, cleansers and deodorants.
Suspected endocrine disrupter and may contribute to antibiotic resistance in
bacteria. Harmful to fish and other wildlife.
11. Phthalates
Phthalates are
a group of endocrine-disrupting chemicals that are found in cosmetics like nail
polish and in synthetic fragrance—both perfumes and fragrance ingredients in
other cosmetic products. Phthalate exposure has been linked to early puberty in
girls, a risk factor for later-life breast cancer. Some phthalates also act as
weak estrogens in cell culture systems.
1,
4-dioxane is not listed on ingredient labels. It is a petroleum-derived
contaminant formed in the manufacture of shampoos, body wash, children’s bath
products and other sussing cosmetics. The International Agency for Research on
Cancer (IARC) has ranked it as a possible carcinogen, and the National
Toxicology Program (NTP) has identified it as a reasonably anticipated
carcinogen.
Ethylene oxide is
found in fragrances and is commonly used to manufacture popular brands of
shampoo. It is classified as a known human carcinogen and is one of the 48
chemicals that the National Toxicology Program (NTP) identifies as mammary
carcinogens in animals.
Polycyclic aromatic
hydrocarbons (PAHs) are a group of chemicals that occur
naturally in coal, crude oil and gasoline. One of the more common PAHs is
naphthalene. Some cosmetics and shampoos are made with coal tar and therefore
may contain PAHs. They have been shown to increase risk for breast cancer.
Placental
extract is derived from human or animal placentas and is used in hair
conditioners, shampoos and other grooming aids, particularly those marketed to
women of colour. The National Toxicology Program (NTP) has identified
progesterone, the major hormonal contaminant in placental extracts, as a
reasonably anticipated carcinogen.
Lead
may be a contaminant in over 650 cosmetic products, including sunscreens,
foundation, nail polishes, lipsticks and whitening toothpaste. Lead is a proven
neurotoxin, linked to learning, language and behavioural problems. It has also
been linked to miscarriage, reduced fertility in men and women, and delays in
puberty onset in girls.
.jpg)
After reading this, you might scare off to apply any those chemicals synthesized make-up products on your face anymore. But don't worry, I know what girls' thinking, even thought they know some chemicals in cosmetic are not good for health but they will not force themselves to stop putting on make-ups on their faces. Why? Because we are girls and we wanted to look the best in front of others. SO, here are some tips for you to choose safe cosmetics:
1. Use Fewer Products with Simpler Ingredients
2. Avoid "Fragrance"
3. Use Truly Natural Cosmetics
4. Beware of Empty Organic and Natural Claims
5. Read the Label to Avoid Synthetic Ingredients
6. Get the Information You Need to Choose Wisely
7. Don't Sweat Over Your Antiperspirant
8. Avoid These Top Offenders:
- Anti-aging creams with lactic, glycolic, AHA and BHA acids
- Hair dyes, especially dark permanent dyes
- Liquid hand soaps with triclosan/triclocarban
- Nail polish and removers with formaldehyde, DBP or toluene (which can be contaminated with benzene)
- Skin lighteners with hydroquinone
- Heavily scented products
- Moisturizers, ointments and skin creams with petrolatum (which can be contaminated with PAHs)
- Fungicides, shaving creams, hair gels and hair coloring containing nonylphenol
- Hair spray, gel, mousse or shaving cream that contains isobutane, a propellant that can be contaminated with 1,3-butadiene
- Sunscreens with UV filters that mimic estrogen
Last, hope you enjoy my blog post. CHEERS! :)
Do you ever wondered why just a small piece of soap can make our bodies clean? It's funny. We've been using soap since birth, yet most of us never even thought about this before now.
What is soap?
Soap is a salt of a fatty acid. There are many different types of fats such as animal fats and vegetable fats. Vegetable fats are usually liquid at room temperature whereas animal fats are usually solid at room temperature. Soaps are made of molecules that are both fat and water soluble. The molecule has a long hydrocarbon tail that allows it to dissolve grease, and a carboxylate polar head that is water soluble. The head is the sodium or potassium salt of an organic acid. Soaps are mainly used as surfactants for washing, bathing, and cleaning.
.jpg)
How soap is made?
Soap is produced from the hydrolysis of fats in a chemical reaction called saponification. Saponification is a chemical reaction between a strong base and a acid, triglyceride (fat or oil) that results in the formation of a salt. There are two ways chemists can accomplish saponification. In both cases, they start with a material rich in triglyceride fats, like animal or vegetable oil.
- One technique involves treating the fat with lye or another very powerful base to saponify it.
In this process, the triglyceride is reacted with a strong base such as sodium or potassium hydroxide to produce glycerol and fatty acid salts. Triglyceride is a compound made of three fatty acids, attached to a single molecule of glycerol. The salt of fatty acid is called soap. Fatty acids are straight-chain monocarboxylic acids. There are two types of fatty acids, saturated fatty acids and unsaturated fatty acids. The carbon-carbon bonds in saturated fatty acids are all single bonds, while unsaturated fatty acids have one or more carbon-carbon double bonds in their chains. Fatty acids are seldom found as free molecules in nature but are most often a part of a larger molecule called a triglyceride. Triglycerides consist of a three-membered carbon chain (glycerol backbone) with a fatty acid bonded to each of the three carbon atoms in the glycerol backbone. The bond between the fatty acid and the glycerol backbone is referred to as an ester linkage. In the saponification process the ester linkage is broken to form glycerol and soap.
This process involves hydrolysis, where water molecules cleave into hydroxide anions and hydrogen cations, yielding glycerol and soap. The acid could be olive oil or coconut oil. Each acid has a unique combination of triglycerides which combines with the base (lye) differently. The base
must always be composed of 1 hydroxide ion. Lye is always use as base
because lye contains one sodium ion and one hydroxide ion. The
equation of saponification is shown below:
- The other requires two steps, one to steam the fat to speed up the reaction and another to treat it with alkali.
When the mix is actually boiled (100 °C+), and after saponification has occurred, the "neat soap" is precipitated from the solution by adding common salt, and the excess liquid is drained off. This excess liquid carries away with it much of the impurities and color compounds in the fat, to leave a purer, whiter soap, and with practically all the glycerine removed. This process tends to result in a soap of purer quality, and the soap may also be less harsh on the skin.
How soap cleans?
Soap is an excellent cleanser because of its ability to act as an emulsifying agent. An emulsifier is capable of dispersing one liquid into another immiscible liquid. There are substances which can be dissolved in water, as for example the salt, and others which can't, as for example oil. Since oil doesn't mix with water, water cannot clean the oil, so soap is needed to suspend oil/dirt so that it can be removed during rinsing. The soap molecules work as a "bridge" between polar water molecules and non-polar oil molecules. Soap molecules have both properties of non-polar and polar at opposite ends of the molecule.
.jpg)
Soap is formed by molecules with a "head" which likes water (hydrophilic) and a long "tail" that hates water (hydrophobic). The head of a soap is a negatively-charged, polar molecule. Its hydrophilic (water-loving) carboxylate group (-CO2) interacts with water molecules via ion-dipole interactions and hydrogen bonding. The hydrophobic (water-fearing) part of a soap molecule, its long, nonpolar hydrocarbon chain, does not interact with water molecules. The hydrocarbon chains are attracted to each other by dispersion forces and cluster together, forming structures called micelles. In these micelles, the carboxylate groups form a negatively-charged spherical surface, with the hydrocarbon chains inside the sphere. Because they are negatively charged, soap micelles repel each other and remain dispersed in water.
Then when soap is added to the water, the long hydrophobic chains of its molecules join the oil particles, while the hydrophilic heads go into the water. The nonpolar hydrocarbon portion of the micelles break up the nonpolar oil molecules. A different type of micelle then forms, with nonpolar soiling molecules in the center. Thus, grease and oil and the 'dirt' attached to them are caught inside the micelle and an emulsion of oil in water is then formed, As a result, the oil droplets repel each other and remain suspended in solution With the rinsing, the emulsion is taken away.
Surfactants are classified by their ionic (electrical charge) properties in water: anionic (negative charge), nonionic (no charge), cationic (positive charge) and amphoteric (either positive or negative charge).
Soap is an anionic surfactant. Water, although a good general solvent, is unfortunately also a substance with a very high surface tension. In the body of the water, each molecule is surrounded and attracted by other water molecules. A tension is created as the water molecules at the surface are pulled into the body of the water. Because of this, water molecules generally prefer to stay together rather than to wet other surfaces and inhibits the cleaning process. Surfactants work by reducing the surface tension of water, allowing the water molecules to better wet the surface and thus increase water's ability to dissolve dirty, oily stains.
Why soap is not effective?
Although soaps are excellent cleansers, they do have disadvantages. They are not effective in hard water. Hardness in water is caused by the presence of mineral salts - mostly those of calcium (Ca) and magnesium (Mg), but sometimes also iron (Fe) and manganese (Mn). The mineral salts react with soap to form an insoluble precipitate known as soap film or scum. The scum cannot rinse away easily. It tends to remain behind and produces visible deposits on clothing and makes fabrics feel stiff. It also attaches to the insides of bathtubs, sinks and washing machines. This reduces the amount of soap available for cleaning
They are also not effective in weak acid. As salts of weak acids, they are converted by mineral acids into free fatty acids. These fatty acids are less soluble than the sodium or potassium salts and form a precipitate or soap scum. Because of this, soaps are ineffective in acidic water. Also, soaps form insoluble salts in hard water, such as water containing magnesium, calcium, or iron. To achieve the same washing or cleaning action, more soap must be added.
CH3(CH2)16CO2-Na+ + HCl → CH3(CH2)16CO2H + Na+ + Cl-
Can you believe that these are actually MADE OF SOAP?
So real right? ;)
Subscribe to:
Posts (Atom)