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Degree of Crystallinity: Definition, Factors Affecting and Determination Methods

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What is Degree of Crystallinity? The degree of crystallinity of the polymer is defined as the fraction of the sample which is crystalline. It can be either expressed in terms of the mass fraction or the volume fraction. The degree of crystallinity by a volume fraction is given by Where,  Xₘ = Degree of crystallinity by mass V = Specific volume of the sample Vₐ = Specific volume of fully amorphous polymer Vc = Specific volume of fully crystalline polymer Factors affecting the degree of crystallinity 1. Molecular weight With the increase in molecular weight of the polymer, the degree of crystallinity increases due to a large number of entanglement of the chain which restricts the growth of a crystallite. 2. Symmetry of repeating unit A symmetrical repeating unit structure like CH₂ makes it easier for the formation of crystallites. Thus, increasing the degree of crystallinity. That's why random copolymers do not crystallize because there is no regularity of the repeating unit. 3. Chai
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Green Solvents: Definition, Examples and Types of Green Solvents

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What are Green Solvents? Green solvents, also known as environmentally friendly bio solvents which are derived from the processing of crops. There are many types of green solvents like ionic liquids, supercritical fluids, water, and supercritical water. These green solvents are way much eco-friendly, less toxic, less hazardous than traditional volatile organic compounds (VOCs). For example, Ethyl lactate Ethyl lactate is a green solvent derived from processing corn. Ethyl lactate is the ester of lactic acid which is used as solvents in the paints and coating industry. Types of Green Solvents 1. Supercritical Fluids A compound that exists above its critical pressure (Pc) and above its critical temperature (Tc) is known as supercritical fluid or SCF. Their chemical and physical properties are between those of a gas and a liquid. Phase diagram showing the supercritical fluid region Supercritical liquids are the perfect replacement for organic solvents for industrial and lab processes d
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Alizarin Dye: Definition, Synthesis, Properties and Application

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What is Alizarin Dye? Alizarin is a red dye having chemical formula C₁₄H₈O₄ which is generally used to dye cotton, wool, and silk.  Alizarin was originally obtained from the root of a common madder plant called Rubia tinctorum. It is also known as Turkey Red as it was best dyed in Turkey and in 1869, it becomes the first natural dye to be duplicated synthetically. Synthesis of Alizarin Following are some methods for the synthesis of alizarin: 1. From anthraquinone The starting material for the synthesis of alizarin is an anthraquinone. It can be easily obtained by Friedel-crafts acylation of benzene with phthalic anhydride. Anthraquinone is then sulfonated with concentrated sulphuric acid at a high temperature to give anthraquinone-b-sulphonic acid. Alizarin is obtained by fusion of anthraquinone-b-sulphonic acid with caustic soda. 2. By bromination of anthraquinone Another synthesis is given by Graeve (in 1869). In this method, anthraquinone is brominated to yield dibromo anthraqui
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