Polyester

Polyester:-

Polyester is a term often defined as “long-chain polymers chemically composed of at least 85% by weight of an ester and a dihydric alcohol and a terephthalic acid”. In other words, it means the linking of several esters within the fibers. Reaction of alcohol with carboxylic acid results in the formation of esters.

Polyester also refers to the various polymers in which the backbones are formed by the “esterification condensation of polyfunctional alcohols and acids”.

Polyester can also be classified as saturated and unsaturated polyesters.

Saturated polyesters refer to that family of polyesters in which the polyester backbones are saturated. They are thus not as reactive as unsaturated polyesters. They consist of low molecular weight liquids used as plasticizers and as reactants in forming urethane polymers, and linear, high molecular weight thermoplastics such as polyethylene terephthalate (Dacron and Mylar). Usual reactants for the saturated polyesters are a glycol and an acid or anhydride.

Unsaturated polyesters refer to that family of polyesters in which the backbone consists of alkyl thermosetting resins characterized by vinyl unsaturation. They are mostly used in reinforced plastics. These are the most widely used and economical family of resins.

Characteristics of polyester

• Polyester fabrics and fibers are extremely strong.
• Polyester is very durable: resistant to most chemicals, stretching and shrinking, wrinkle resistant, mildew and abrasion resistant.
• Polyester is hydrophobic in nature and quick drying. It can be used for insulation by manufacturing hollow fibers.
• Polyester retains its shape and hence is good for making outdoor clothing for harsh climates.
• It is easily washed and dried.

Uses of Polyester

The most popular and one of the earliest uses of polyester was to make polyester suits – all the rage in the 70s. Polyester clothes were very popular. Due to its strength and tenacity polyester was also used to make ropes in industries. PET bottles are today one of the most popular uses of polyester.

Bio-Fuel

                                                                  BIO FUEL

Biofuels are fuels largely derived from living organisms that use the sun as their main energy input. Energy may be put into planting, fertilizing, harvesting, and processing the crops, but most of the energy, in the final plant product, comes from the sun. Through the process of photosynthesis plants convert solar energy into chemical forms of energy (carbohydrates, fats, etc.). Plant convert solar energy into a chemical form more usable as a fuel. Biofuels are considered carbon neutral. That is, they release no net amount of carbon dioxide into the atmosphere.This because the carbon dioxide that is released during combustion was originally absorbed from the atmosphere during the process of photosynthesis.Hence, no extra CO2 is pumped into the atmosphere The process of photosynthesis can be summarised by the equation below.

6H2O + 6CO2 => C6H12O6 + 6O2

Palm oil is used to produce biofuel.  . A process known as transesterification is commonly used to produce biodiesel. Chemically, transesterification is the process of exchanging the alkyl group of an ester with another alkyl group, from a different alcohol. Vegetable oil contains fatty acids bonded to glycerol to form triglycerides. In the case of biodiesel, a vegetable oil ester is combined with a simple alcohol, methanol, and a catalyst, resulting in the breakup of the triglyceride ester to form glycerol and three methyl esters (biodiesel) A typical molecule of biodiesel looks like the structure below.  Mostly it is a long chain of carbon atoms, with hydrogen atoms attached, and at one end is what wecall an ester functional group .

Making good biodiesel requires several other steps besides the transesterification reaction(as shown in the right).  The first is to remove any traces of water in the vegetable oil.  If this is not done, the water will later react with the vegetable oil in the reaction and make soap.

If soap gets made, then later it complicates the steps after the transesterication reaction that are needed to separate the biodiesel from leftover methanol, the NaOH or KOH catalyst, and the glycerol byproduct.Diesel engines can burn biodiesel fuel with no modifications (except for replacing some rubber tubing that may soften with biodiesel).  This is possible because biodiesel is chemically very similar to regular diesel, shown below.  Notice that regular diesel also has the long chain of carbon and hydrogen atoms, but doesn’t have the ester group.Actually, the first diesel engines didn’t run on “diesel” fuel, but on vegetable oil, a sample molecule of which is shown below.  Notice that it also has the long rows of carbon and hydrogen atoms, but is about three times larger than normal diesel molecules.  It also has ester functional groups , like biodiesel.That larger size of vegetable oil means that in cold weather it gels, making it hard to use in an engine.  Converting it into biodiesel makes it a smaller molecule, closer to the size of regular diesel, so that it has to get colder than vegetable oil before it starts to gel.

Miracle Of Tooth Paste with chemistry

Miracle Behind The Shiny Teeth !

Toothpaste is probably the first product that everyone use in the morning as well as the last before going to bed. A smile with white and healthy teeth and gums is what everyone wants to have. Every toothpaste contains binders, abrasives, flavors, sweeteners, fluorides, tooth whiteners, a preservative, and water.
     Toothpaste, which contains sodium fluoride, belongs to the group of weak bases. The high pH of the toothpaste helps to kill the bacteria that reside in our mouth at the time of brushing. Those bacteria prefer a neutral to slightly acidic environment, exactly the conditions of our unbrushed mouth. Tooth enamel naturally loses its minerals and decays. Fluoride works with calcium and phosphate to slow this process and improve remineralization, or the production of new tooth enamel. Fluorides reduce decay by increasing the strength of teeth. Sodium fluoride is the most commonly used fluoride. Sodium perborate is used as a tooth whitening ingredient. Most toothpastes contain the preservative p-hydrozybenzoate. Water is also used for dilution purposes. Fluoride has also been added to other dental products like mouthwash and the fluoride varnish used by dentists.      So, brushing your teeth twice in a day is very important as it keeps your teeth clean and shiny like this,

Secret of Scent(Perfumes)

Secret Behind The Wonderful Scent World!!!

   Nowadays, perfumes are commonly and widely being used in daily life by everyone. Perfume has been used for century to cover the body odor.

   Perfumes encompass a wide variety of chemicals (called notes), which are tailored for specific occasions and seasons. In fact, most of the perfumes are engineered to have three-part of structure.

1)Top notes: light scent that fade quickly

2)heart notes: scent last for several hours

3)Base notes: Scent stick stubbornly to the skin

  A perfume basically consists of 78-95% of ethyl alcohol, and the rest are essential oils. Staying power of the perfume is highly depend by the rate of evaporation.

  Many methods are used to synthesis the perfume.

A) Maceration

1) Raw ingredients are soaked in the solvent.

2) The fragrances are drawn out and collected.

B) Expression

1) Raw ingredients are being compressed.

2) The aromatic oils are being squeezed out.

   By using perfume, our will smell amazingly unique, provides ultimate expression of individuality and causing others to take notice of ours unique style and grace. 

Cosmetics Secret

Secret of beauty J

  Cosmetics (colloquially known as makeup or make-up) are care substances used to enhance the appearance or odor of the human body. They are generally mixtures of chemical compounds, some being derived from natural sources, many being synthetic.

   In the U.S., the Food and Drug Administration (FDA) which regulates cosmetics, defines cosmetics as "intended to be applied to the human body for cleansing, beautifying, promoting attractiveness, or altering the appearance without affecting the body's structure or functions." This broad definition includes, as well, any material intended for use as a component of a cosmetic product. The FDA specifically excludes soap from this category.

 

   During the 20th century, the popularity of cosmetics increased rapidly. Cosmetics are increasingly used by girls at a young age, especially in the United States. Due to the fast-decreasing age of make-up users, many companies, from high-street brands like Rimmel to higher-end products like Estee Lauder, have catered to this expanding market by introducing more flavoured lipsticks and glosses, cosmetics packaged in glittery, sparkly packaging and marketing and advertising using young models. The social consequences of younger and younger beautification  had much attention in the media over the last few years.

    Criticism of cosmetics has come from a variety of sources including some feminists, religious groups, animal rights activists, authors and public interest groups. Growing awareness and preference for cosmetics exists for cosmetics lacking toxic ingredients, especially those derived from petroleum,sodium lauryl sulfate (SLS), and parabens.

Beauty can make happy J

Cosmetics are regarded as a means of enhancing one's complexion and beautifying the skin. For examples,

·        Skin creams and lotions can be used to deep-cleanse the skin.

·        If pores in the skin are blocked, it may lead to infection and acne formation. Various cosmetic cleansing products thoroughly cleanse the skin and remove the dirt and microorganisms from the skin.
·        After cleansing, moisturizers are applied to prevent drying of the skin and to keep it smooth and radiant. Moisturizers also offer excellent protection against cold winds and act as a lubricating agent.

·       There are special sun-protection creams/lotions that can protect you from the harmful UV rays of the sun. These creams minimize the risk of skin cancer, which is the result of exposure to sun rays.

·        Many cosmetics contain vitamins such as A, D, E and K. These vitamins are essential for healthy skin and hair.

·       To cope with body odor, one can use deodorants and perfumes. These help in making one feel fresh all through the day.

·       Apart from skin care, there are also varieties of shampoos and conditioners available, which keep the hair clean, soft and healthy.

Besides that, cosmetics are used not only for skin care, but also to treat certain skin problems. Dark spots or pimples on the face can be hidden using cosmetic products like concealers. You can enhance your most attractive facial features using makeup. Moreover, you can also cover dark circles and wrinkles using various anti-aging creams and eye makeup. Apart from that, not only your face, you can also decorate your nails using attractive nail colours. The wide range of hair colours available today also helps you to modify and highlight your hair in the colour and shade of your choice.

Sometimes too much beauty is not good for health L

  Increasingly, people react to the pollution in their environment with skin diseases and allergies. Just five to ten percent of the approximately 30 million allergy sufferers in Germany react excessively to certain additives and preservatives, both in their food and in their cosmetic products.

    Over the years, numerous methods were developed that were aimed at making products more durable and less perishable. As part of this, countless synthetic additives, which were then admixed to the care products to preserve these longer. Meanwhile, many of these substances are suspected trigger allergies or even cancer can. These findings are based on long-term studies, only in the wake of the global disease spread and thus many people could be made. In spite of previous laboratory and animal experiments, it was not possible to study these long-term effects before the introduction of these substances. The result we see now: Excessive sensitivity of many people on certain products.

  In a nutshell, cosmetics can bring about a huge change in your personality. However, you need to be cautious while using the same. Before buying any cosmetic products, make sure that they are meant for your skin type lest you want to break out into an allergy. Buy products of reputed brands and you will be assured of excellent quality.

Why Can’t Soap Cleanse Our Clothes?

Why Can’t Soap Cleanse Our Clothes?

Soap is the result of the mixture of potassium salts of fatty acids which is obtained from vegetable oils or animal fats and which is reacted with an alkali such as potassium hydroxide. This process of reacting the potassium salts of fatty acids with an alkali is known as saponification.

The saponification process is mostly practiced and performed for the making of soap industrially. This process involves the process of heating animal fats or vegetable oil and reacting with an alkali in order to give the result of soap and water mixed with glycerine. The another part of the process is neutralization of fatty acids with an alkali. The fats and oils are hydrolyzed with a high-pressure steam to produce fatty acids and glycerine. After that, the fatty acids is purified by distillation and neutralization with an alkali to yield soap and water.

If the alkali is sodium hydroxide, then, the sodium soap will be formed. Sodium soaps are made in solid form. Thus, they are also known as ‘hard’soaps. In contrast, if the alkali is potassium hydroxide, then, the soap formed will be smoother and is found in liquid form. This type of soaps is usually found in liquid-hand soaps and shaving cream. The carboxyl group present at the end of the soap molecule is attracted towards the water which is hydrophilic while the other end of the soap molecule which is a hydrocarbon chain is attracted to oil and grease which are non-polar substances rejected by water molecules. This end is known as the hydrophobic end.

Although,soap is a cleaning agent, the cleaning action of soap is affected by water hardness. Soap is proved to be less efficient in cleaning when dissolved in hard water. The water is labeled as hard water due to the presence of mineral salts such as Calcium ions and Magnesium ions which contributes to the formation of the insoluble precipitate also known as scum when soap reacts with these mineral salts. The scum formed on clothes makes the fabric stiff and thus causes a visible stain to deposit on clothes. Moreover, scum attaches to the internal parts of washing machines.

The reaction of soaps with hard water decreases the amount of soap present to be used for the cleaning action. However, if soap is let to react with soft water, the soil on stains and dirts on the clothes shows the presence of mineral salts which eventually reduces the effectiveness of soap in the cleaning action. Therefore, soap is inflexible to be used for laundry purposes, especially in a variety of fibres, washing temperatures and water conditions nowadays.

 

 

Organic chemistry Introduction

Introduction to organic chemistry:-

Organic chemistry is the study of carbon and the study of the chemistry of daily life. Life is based on carbon's ability to form diverse structures and an endless number of different carbon based on molecules. We are living in a world which is largely shaped by organic compounds. There is hardly any walk of life where we do not need the organic compounds. The food that we eat is essentially a mixture of organic compounds. The changes which the food undergoes in our bodies are organic chemical reactions. The clothes that we wear (wool, cotton, leather, synthetics) are all organic in character. The soap, cosmetics, perfume, oils, plastics, explosives, rubber, dyestuffs, paper, insecticides, and many more are all organic compounds. The sources of primary energy we still use every day (petroleum, natural gas, coal) are organic in nature. In the medical field, organic compounds are indispensable. Antibiotics, sulpha drugs, alkaloids, aspirin, iodoform, and many are organic compounds. There is hardly any industry which is not dependent on organic compounds.

            Organic chemistry is that branch of chemistry that deals with the structure, properties, and reactions of compounds that contain carbon. It is a highly creative science. In addition to being plentiful, organic compounds are also unique. This is because carbon atoms have the ability to form strong bonds with many different elements. Carbon atoms are also able to bond covalently to other carbon atoms, while simultaneously forming strong bonds with other nonmetal atoms. When carbon atoms bond together, they can form chains consisting of thousands of atoms. They can also form rings, spheres, and tubes.

 Chemists in general and organic chemists in particular can create new molecules never before proposed which, if carefully designed, may have important properties for the betterment of the human experience. In terms of Ph.D. population, organic chemistry is the largest chemistry discipline, in both total numbers, annual Ph.D. graduates, and in annual production. Organic chemistry is the study of carbon and the study of the chemistry of life. Since not all carbon reactions are organic, another way to look at organic chemistry would be to consider it the study of molecules containing the carbon-hydrogen (C-H) bond and their reactionsOrganic chemistry is a branch of chemistry that involves the study of organic carbon compounds. It encompasses the structures, composition, and synthesis of carbon-containing compounds. In understanding organic chemistry, it is important to note that all organic molecules consist not only of carbon, but also contain hydrogen. While it is true that organic compounds can contain other elements, the bond between carbon and hydrogen is what makes a compound organic.

Originally, organic chemistry was defined as the study of compounds created by living organisms. However, its definition has been enlarged to include artificially synthesized substances as well. Before 1828, all organic compounds were obtained from living organisms. Scientists didn’t believe it was possible to synthesize organic compounds from inorganic compounds. Many attempted to do so and failed. However, in 1828, urea was synthesized from inorganic substances, paving the way for a new definition of organic chemistry.

Organic chemistry deals not only with the chemistry of life and the natural carbon compounds but also with the huge, increasing number of synthetic carbon compounds. We are living in a world which is largely shaped by organic compounds. There is hardly any walk of life where we do not need the organic compounds. There is hardly any industry which is not dependent on organic compounds. It is the most beautiful branch of science which has great applications in our everyday life. All our requirements would not have been fulfilled without the knowledge of organic chemistry. The understanding of organic chemistry dates back to the nineteenth century. Scientists claimed that things obtained from plants are too complex to study and recreate in the laboratory. Inorganic chemistry, another main branch of chemistry, was believed to be much simpler and easier to do research. The scientists believed that all the organic matter were held by a vital force. They then named these compounds as organic.