Bisphenol A is an organic compound that is processed synthetically and belongs to the diphenylmethane and bisphenol with two hydroxyphenyl groups attached to the carbon atom of the main chain. Its chemical formula is (CH3)2C(C6H4OH)2. Alternatively, bisphenol A (BPA) definition is that it is a synthetically obtained colourless crystalline organic compound that occurs in the solid phase belonging to the diphenylmethane group and is soluble in organic solvents but poorly dissolves in water (0.344 % wt. At 830C). The diagrammatic representation of the bisphenol A structure is given below.
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Bisphenol A structure represents a bisphenol 4,4’- methanediylphenol in which two methyl groups replace the methyl hydrogens attached with the carbon having a tetrahedral bond. BPAs are mostly used to manufacture certain plastic grades like polycarbonate plastics, some polysulfones and epoxy raisins, that are key material of plastic bottles, baby bottles and food and beverage containers. These are basically the byproducts that leach from the other products that are subjected to health and environmental degradation. BPA is a xenoestrogen and mimics estrogen present in the body, thus exhibiting hormone-like properties. Therefore, the EPA (environmental protection agency) in the USA has set a maximum permissible limit of BPA in the human body below 50 micrograms per kilogram of body weight per day.
Some of the Important Physicochemical Properties of Bisphenol A are Listed Below:
BPA Physico-Chemical Properties
The Chemical Properties of BPA are Listed below.
Bisphenol A Uses
BPA polycarbonate plastics are very sturdy in nature. Due to their high melting point, they have the ability to withstand high temperatures even inside microwaves. Thus they are used to make large variants of microwave-proof utensils.
Because of its high density, it has the capability to withstand high impact collisions. Thus they are very susceptible as a material for safety glasses, bulletproof windows and helmets.
Bisphenol A acts as a component in epoxy resins that are very good coating agents and therefore is used for the protective coating of pipelines and to cover the inner surface of food cans. This helps the food and beverages to last long without any decay. In 2003, the USA used 856000 tons of BPA to produce 21% of epoxy raisins that are mostly used in the printing industry for making sale receipts and other coating papers.
Due to their resiliency, they are used in many medical devices such as heart-lung machines, incubators, artificial kidney, dental fillers and sealants and due to their optical clarity it is also used as eyewear glasses.
BPA is used as the main agent for the production of major classes of resins. Alkylation of BPA with epichlorohydrin results in the formation of vinyl ester resins.
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It is a typical vinyl ester resin that is derived from bisphenol A diglycidyl ether. This is a bid cross-linking polymer produced by free radical polymerization.
Health and Environmental Effects
Some of the Biological Effects are Mentioned below:
Since bisphenol A acts as a xenoestrogen, it mimics the estrogen present in the body and thus shows the properties of certain hormones. Thus phenol containing molecules that are similar to that of BPA shows weak estrogenic properties and thus acts as an estrogenic chemical and endocrine disruptor. It also possesses the property that interrupts the nerve network that manages the signal for the development of the reproductive system in humans and animals.
BPA acts as a binder for both nuclear estrogen receptors, namely, ER alpha and ER beta. Though it is 1000 - 2000 times less fold potent than estradiol, it has the ability to mimic estrogen indicating that it is a selective estrogen receptor modulator t (SERM) and also antagonises estrogen. At high concentration, BPA also has the ability to act as an antagonist of the androgen receptor.
Few of the research shows that it causes stress and increases anxiety in rats. Thus, overexposure to it is harmful during pregnancy and the development of infants. Thus in 2012, the use of bisphenol was banned in baby products like feeding bottles, teethers etc. by the Food and Drug Administrator in the USA.
Some of the Environmental Effects of Bisphenol A are:
BPA can enter into the environment directly through the leaching of chemicals, or degradation of plastic bottles, industries that use BPA casting sands, paper and other recycling industries, plastic coating and straining manufacturers. These go straight into the land rendering it unfertile and barren making it unsuitable for agriculture.
BPA mostly affects the growth and reproduction of marine life. Fishes are the most sensitive species of freshwater. BPA causes endocrine effects in fish, amphibians and reptiles. The relevant exposure level of BPA in the environment is much higher than the level optimized for acute toxicity.