Introduction
Chemical modification is a method of changing the physics and chemical properties of the polymer by chemical reaction. If the hard segment of the polystyrene is too strong, the polyethylene soft segment can be introduced to increase toughness; nylon, a polyester, or the end group (amino group, carboxy, hydroxyl group, etc.), which can be used for one-membered acid (benzoic acid or B The anhydride), a metallol (cyclohexanol, butanol or benzyl alcohol or the like) is performed; the alkyd polyester, which is polycondensated from the polyol and polymerized acid, and the fatty acid can be remarkable after adding fatty acids. Improve its moisture resistance and water resistance, and the elasticity is also improved.
Chemical Change
Chemical changes are generally existed in production and life. Such as iron rust, festival fireworks, acid bases, etc. Macroscopic can see a new substance, which is a chemical variation. From the micro-chemical changes, the essence of the chemical reaction before and after, there is no change in the number of atoms, only the combination of atoms and atoms has changed. For example, for molecular compositions, the atom recombines into a new substance. The chemical properties of the substance need to be chemically changed by substances to exhibit, so it can be used to study the chemical properties of the substance by chemical reactions in the substance, and new substances can be used.
Chemical change often accompanied by light, heat, gas, precipitation or color odor change, etc., can be used to determine whether thereto has occurred without chemical reactions. But pay attention to the difference between physical changes. Physical changes are often accompanied by luminous (electric lamps), exothermic (friction), release gas (open soda bottle cap), color change (oxygen becomes liquid oxygen), etc., only no new substance is generated, this is physical changes The fundamental difference between chemistry changes. Depending on the reactants, the species species can be divided into four basic types of chemical reactions into combination, decomposition, replacement, and digestion. It is also possible to classify chemical reactions from other angles, such as dividing an oxidative reduction reaction with non-oxidative reactions; heat absorption reactions and exothermic reactions, and the like. The nature of the object in the chemical changes is chemical.