The mobile phase and stationary phase in the HPLC will involve in the mechanism. The stationary phase in HPLC normally will be the silica gel. The silica gel will help to separate the components in the liquid sample as its particle size, surface properties and pore structure will lead to good separation results of solvent by minimize the length of diffusion path. The silica gel is also inert to most solvent so it can separate various type of chemical compound with high reproducibility. During the separation, the component in sample will interact with the adsorbent material within the pores of the stationary phase.
Aromaticity can be termed as a chemical property of conjugated cycloalkenes. Aromaticity deals with the uncommon stability of benzene and its derivatives, which is caused by the ability of the electrons in the p-orbitals to delocalize and act as a framework to generate planar molecules. A molecule is only considered aromatic due to the fact that it is cyclic, that it follows the Huckel’s Rule and lastly that each element must have a p-orbital. Antioxidants play and important role in health. It can be defined as a group of organic chemicals and have been used to hinder the process of oxidative degradation of food products, fats and oils and polymers.
These control the release rate of the drug from the patches. These are prepared by dispersing the drug in polymeric base solution. There are some polymers used in preparation of Transdermal patches: Natural polymers: such as, cellulose derivatives, Zein, Gelatin, Shellac, Waxes, Proteins, Gums and their derivatives, Natural rubber, Starch etc. Synthetic Elastomers: e.g. polybutadiene, hydrin rubber, polyisobutylene, silicon rubber, nitrile, acrylonitrile, neoprene, butyl rubber etc.
High density PLA is created by heating the lactic acid with an acid catalyst to create a cyclic lactide. This undergoes a ring-opening polymerization to form high density polyactic acid. There is still research being done on how to create cheap and eco friendly
Solvent used in the elution process would be the mobile phase and solvents of different polarity would have a significant impact on the separation due to the varying solubility of compounds in different solvents. Hexane, being the less polar solvent, interacts mainly with the less polar analytes but very slowly with polar analytes. Therefore using hexane at the start of the elution process allows the less polar compound to be eluted out first. After the complete collection of less polar analyte, the mobile phase was changed to the more polar hexane/ethyl acetate solvent, which has stronger interaction with the more polar component, allowing it to be eluted out faster. The change in solvents throughout the elution process would allow for an effective and efficient separation of the compounds β-carotene and chlorophyll in the crude extract of green leaves.
They can impart localised structural rigidity, confer cytotoxicity by alkylation, or be secondary metabolites . The chemistry of epoxides is dominated by the reactions that involve opening of the strained three-membered heterocyclic ring by nucleophiles. Such reactions yield valuable bifunctional compounds. In nature, epoxide ring opening is catalysed by the phenolic proton of a tyrosine moiety . But in laboratory, the cleavage usually occurs in non-aqueous media in presence of a Lewis acid catalyst like Al2O3, Li+, Mg2+ etc.
Polypropylene forms the head to tail structure through polymerization. There is strong covalent bonds between these atoms but weak Van der waals force (dipole-dipole force) between Polypropylene molecules. Isotactic Polypropylene forms a somewhat tetrahedral arrangement and its molecules are asymmetrical. These molecules form a long polymer chain.
Aliphatic polyesters Aliphatic polyesters are the most widely biodegradable polymers that used in environmental and biomedical fields. In general, these polymers are synthesized via chemical polycondensation reactions using catalyst such as titanium oxides (Gross R.A et.al. 2010; Yang et al., 2012).A wide range of aliphatic polyesters can be designed by using various reactants and changing the synthesis conditions to meet specific requirements such as hydrophobicity, crystallinity, solubility, degradability, glass transition temperature, melting temperature and so on (Clarinval A-N., 2005). 1.1.2. Aliphatic polyesters synthesis Polyesters were historically the first family of synthetic condensation polymers and were investigated as part of Carothers’ pioneering
Investigating how the composition and the structure affect the parent material of polymers: We are using Plastics widely everywhere and so many types of plastics we have. The additives change the structure and the composition of the polymer. Plastic is a polymer we use plastics everywhere soft plastic is used as covers and hard plastic is used as tables in our daily life without plastics we can’t live. Additives are needed for plastics because additives make plastics safer, tougher, colourful and cleaner plastics can be made. They reduce manufacturing cost will be reduced and the product lives longer.
Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. There are many different types of plastics such as: • Polyester (PES) – Fibers, textiles. • Polyethylene terephthalate (PET) – Carbonated drinks bottles, peanut butter jars, plastic film, microwavable packaging. • Polyethylene (PE) – Wide range of inexpensive uses including supermarket bags, plastic