Common objects that have become familiar to uswhich are ubiquitous in our daily life, it would have been impossible to imagine without using products of organic chemistry. Long before Anselm Paya’s chemical experiments, as a result of which he was able to detect and describe a polysaccharide in 1838, which received its own name “cellulose” (a derivative of French cellulose and Latin cellula, which means cell, cell) the most indispensable things.
Increased knowledge of pulp has led toa variety of things made on its basis. Paper of various grades, cardboard, plastic parts and from artificial fibers (acetate, viscose, copper-ammonia), polymer films, enamels and varnishes, detergents, food additives (E460) and even smokeless powder are products of pulp production and processing.
In its pure form, cellulose is a white solid with quite attractive properties, exhibits high resistance to various chemical and physical effects.
Природа избрала целлюлозу (клетчатку) своим the main building material. In the plant world, it forms the basis for the cell walls of trees and other higher plants. In its purest form in nature, cellulose is found in the hairs of cotton seeds.
The unique properties of this substance are determinedits original structure. The formula of cellulose has a general record (C6 H10 O5) n from which we see a pronounced polymeric structure. Repeated a huge number of times the residue of β-glucose, which has a more expanded form as - [C6 H7 O2 (OH) 3] -, combines into a long linear molecule.
Molecular formula of cellulose determines itsunique chemical properties resist aggressive media. Also, cellulose has a high resistance to heat, even at 200 degrees Celsius, the substance retains its structure and is not destroyed. Self-ignition occurs at a temperature of 420 ° C.
Cellulose is no less attractivephysical properties. The structural formula of cellulose in the form of long filaments containing from 300 to 10,000 glucose residues that do not have side branches, largely determines the high stability of this substance. The glucose formula shows how many hydrogen bonds give cellulose fibers not only great mechanical strength, but also high elasticity. The result of the analytical processing of many chemical experiments and research was the creation of a model of a cellulose macromolecule. It is a rigid helix with a step of 2-3 elementary units, which is stabilized by intramolecular hydrogen bonds.
Not the formula of cellulose, but the degree of its polymerizationis the main characteristic for many substances. So in raw cotton, the number of glucoside residues reaches 2500-3000, in purified cotton - from 900 to 1000, purified wood pulp has an indicator of 800-1000, in regenerative cellulose their number is reduced to 200-400, and in industrial cellulose acetate it ranges from 150 up to 270 "links" in the molecule.
Продуктом для получения целлюлозы служит vegetable raw materials, mainly wood. The main technological process of production involves cooking chips with various chemicals, followed by cleaning, drying and cutting the finished product.
Последующая обработка целлюлозы дает возможность get a lot of materials with given physical and chemical properties that allow to produce a variety of products, without which the life of a modern person is difficult to imagine. The unique formula of cellulose, corrected by chemical and physical processing, became the basis for obtaining materials that have no analogues in nature, which allowed them to be widely used in the chemical industry, medicine and other branches of human activity.
