Melting point 210–260 °C; Nylon 6,6 is degraded by strong acids but is resistant to alkalis. It is also resistant to most organic solvents, but can be dissolved in formic acid or phenol. Susceptible to ultraviolet radiation. If you wet nylon, it will lose from 7 to 20% of its strength Strength does not decrease at low temperatures down to -40°C Molecular weight 8–40 thousand Density 1010–1140 kg/m3 Physical properties
Nylon-66 is synthesized by the polycondensation of adipic acid and hexamethylenediamine. To obtain a polymer with maximum molecular weight, a salt of adipic acid and hexamethylenediamine (AG-salt) is used: The synthesis of nylon-6 (nylon) from caprolactam is carried out by hydrolytic polymerization of caprolactam using the “ring opening addition” mechanism: Chemical properties
Textile industry - women's stockings, jackets, socks, umbrellas, wedding veils, sports equipment, carpets, ropes, for the production of knitwear, for the creation of parachutes, body armor, military uniforms, life jackets. Automotive industry - Wheel caps. Rear view mirror housing. Fan shrouds. Windshield washer water heater. Outboard motor housings. Radiator tanks. Cylinder head covers... Instrumentation - Racks, rivets, plugs, screws, buttons, bushings, washers. Staples, clamps, holders, ties for fastening wires and cables. Medicine - dental prosthetics, for bone regeneration and replacement Mechanical engineering - creating foundry molds Electrical industry - Polymer batteries Also used in 3D printing Eyeglass frames, fishing nets, guitar strings are made from nylon
Advantages and Disadvantages *Excellent shockproof properties. *Good mechanical properties. The elasticity of polyamide-6,6 is higher than that of cellulose acetate, it wears out less and is 15% lighter. *Its transparency allows you to achieve special shine and original color effects. *features softness and lightness *Tendency to dry out, causing the material to become brittle. *Limited coloring options in bulk. *Sensitivity to ultraviolet radiation (turns yellow).
The name of this material consists of two words: N.Y. (New York) and Lon (London). First produced on February 28, 1935 by Wallis Carazes at Dupont. Nylon is the first synthetic fiber that was made entirely from coal, water and air. Well-known manufacturers - “Honeywell Nylon Inc”, “Invista”, “Wellman Inc”, “Dupont”. Nylon toothbrushes are like a file that erases enamel and spoils gums and more. This is interesting
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Presentation on the topic: Polymers Application
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PolymersInorganic and organic, amorphous and crystalline substances consisting of “monomeric units” connected into long macromolecules by chemical or coordination bonds. A polymer is a high-molecular compound: the number of monomer units in the polymer (degree of polymerization) must be quite large. In many cases, the number of units can be considered sufficient to classify the molecule as a polymer if the molecular properties do not change when adding another monomer unit. As a rule, polymers are substances with a molecular weight from several thousand to several million
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If the connection between macromolecules is carried out using weak Van Der Waals forces, they are called thermoplastics, if through chemical bonds, they are called thermosets. Linear polymers include, for example, cellulose, branched polymers, for example, amylopectin, there are polymers with complex spatial three-dimensional structures. If the connection between macromolecules is carried out using weak Van Der Waals forces, they are called thermoplastics, if using chemical bonds, they are called thermosets . Linear polymers include, for example, cellulose; branched polymers, for example, amylopectin; there are polymers with complex spatial three-dimensional structures. In the structure of a polymer, a monomer unit can be distinguished - a repeating structural fragment that includes several atoms. Polymers consist of a large number of repeating groups (units) of the same structure, for example, polyvinyl chloride (-CH2-CHCl-)n, natural rubber, etc. High-molecular compounds, the molecules of which contain several types of repeating groups, are called copolymers or heteropolymers.
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A polymer is formed from monomers as a result of polymerization or polycondensation reactions. Polymers include numerous natural compounds: proteins, nucleic acids, polysaccharides, rubber and other organic substances. In most cases, the concept refers to organic compounds, but there are also many inorganic polymers. A large number of polymers are obtained synthetically based on the simplest compounds of elements of natural origin through polymerization reactions, polycondensation and chemical transformations. The names of polymers are formed from the name of the monomer with the prefix poly: polyethylene, polypropylene, polyvinyl acetate, etc. The polymer is formed from monomers as a result of polymerization or polycondensation reactions. Polymers include numerous natural compounds: proteins, nucleic acids, polysaccharides, rubber and other organic substances. In most cases, the concept refers to organic compounds, but there are also many inorganic polymers. A large number of polymers are obtained synthetically based on the simplest compounds of elements of natural origin through polymerization reactions, polycondensation and chemical transformations. The names of polymers are formed from the name of the monomer with the prefix poly: polyethylene, polypropylene, polyvinyl acetate, etc.
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Features: Special mechanical properties: elasticity - the ability to undergo high reversible deformations under a relatively small load (rubbers); low fragility of glassy and crystalline polymers (plastics, organic glass); the ability of macromolecules to orient under the influence of a directed mechanical field (used in the manufacture of fibers and films). Features of solutions polymers: high solution viscosity at low polymer concentration; polymer dissolution occurs through the swelling stage. Special chemical properties: the ability to dramatically change their physical and mechanical properties under the influence of small quantities of a reagent (rubber vulcanization, leather tanning, etc.). Special properties of polymers are explained not only by their large molecular weight, but also by the fact that macromolecules have a chain structure and are flexible.
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Classification According to the chemical composition, all polymers are divided into organic, organoelement, inorganic. Organic polymers. Organoelement polymers. They contain inorganic atoms (Si, Ti, Al) in the main chain of organic radicals, which combine with organic radicals. They don't exist in nature. An artificially obtained representative is organosilicon compounds.
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Polymers are dividedPolymers are divided according to polarity (affecting solubility in various liquids). The polarity of polymer units is determined by the presence in their composition of dipoles - molecules with an isolated distribution of positive and negative charges. In nonpolar units, the dipole moments of atomic bonds are mutually compensated. Polymers whose units have significant polarity are called hydrophilic or polar. Polymers with non-polar units - non-polar, hydrophobic. Polymers containing both polar and non-polar units are called amphiphilic. Homopolymers, each unit of which contains both polar and nonpolar large groups, are proposed to be called amphiphilic homopolymers.
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With respect to heat, polymers are divided into thermoplastic and thermosetting. Thermoplastic polymers (polyethylene, polypropylene, polystyrene) soften when heated, even melt, and harden when cooled. This process is reversible. Thermosetting polymers, when heated, undergo irreversible chemical destruction without melting. Molecules of thermosetting polymers have a nonlinear structure obtained by cross-linking (for example, vulcanization) of chain polymer molecules. The elastic properties of thermosetting polymers are higher than those of thermoplastics, however, thermosetting polymers have practically no fluidity, as a result of which they have a lower fracture stress. In relation to heating, polymers are divided into thermoplastic and thermosetting. Thermoplastic polymers (polyethylene, polypropylene, polystyrene) soften when heated, even melt, and harden when cooled. This process is reversible. Thermosetting polymers, when heated, undergo irreversible chemical destruction without melting. Molecules of thermosetting polymers have a nonlinear structure obtained by cross-linking (for example, vulcanization) of chain polymer molecules. The elastic properties of thermosetting polymers are higher than those of thermoplastics, however, thermosetting polymers have practically no fluidity, as a result of which they have a lower fracture stress. Natural organic polymers are formed in plant and animal organisms. The most important of them are polysaccharides, proteins and nucleic acids, of which the bodies of plants and animals largely consist and which ensure the very functioning of life on Earth
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ApplicationMaterials obtained from polymers1. Fibers based on polymers are obtained by pressing solutions or melts through dies with subsequent solidification; these are polyamides, polyacrylonitriles, etc.2. Polymer films are produced by pressing through dies with slot-like holes or by applying to a moving belt. They are used as electrical insulating and packaging material, the basis of magnetic tapes. 3. Varnishes are solutions of film-forming substances in organic solvents.4. Adhesives, compositions capable of connecting various materials due to the formation of strong bonds between their surfaces with an adhesive layer.5. Plastics6. Composites are composite materials with a polymer base reinforced with filler.
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Areas of application of polymers Areas of application of polymers 1. Polyethylene is resistant to aggressive environments, moisture-proof, and is a dielectric. It is used to make pipes, electrical products, parts of radio equipment, insulating films, cable sheaths for telephone and power lines.2. Polypropylene is mechanically strong, resistant to bending, abrasion, and elastic. Used for the manufacture of pipes, films, battery tanks, etc.3. Polystyrene is resistant to acids. Mechanically strong, is a dielectric. Used as an electrical insulating and structural material in electrical engineering and radio engineering.4. Polyvinyl chloride is flame retardant, mechanically strong, electrical insulating material.5. Polytetrafluoroethylene fluoroplastic dielectric does not dissolve in organic solvents. It has high dielectric properties over a wide temperature range (from -270 to 260ºС). It is also used as an antifriction and hydrophobic material.6. Polymethylmethacrylate plexiglass - used in electrical engineering as a structural material.7. Polyamide – has high strength, wear resistance, and high dielectric properties. 8. Synthetic rubbers (elastomers).9. Phenol-formaldehyde resins are the basis of adhesives, varnishes, and plastics.
Almost 10 times lighter than cork(average density no more than 20 kg/m 3 );
Coefficient of thermal conductivity 0.03 W/(m×K).
It chars, but does not burn in an open flame at 500 °C, and when introduced into the composition flame retardants do not ignite in an oxygen environment.
It has significant water absorption and sensitivity to aggressive chemicals. During storage and operation, it is protected with cellophane or plastic film.
Used as heat and sound insulation material in construction, in the manufacture of refrigeration units, storage facilities and vessels for transporting liquid oxygen, as a filler for hollow structures in transport engineering.
Urea glue
adhesive based on urea-formaldehyde and melamine-formaldehyde resins resins (so-called urea resins), as well as their mixtures.
used in large quantities in the woodworking industry in the manufacture of plywood, furniture, etc.; used for gluing phosphorus and metal.
is an aqueous solution of urea resin. Often the glue contains hardener (oxalic, phthalic, hydrochloric acids or some salts) and filler (legume or cereal flour, starch, wood flour, gypsum, etc.).
For example, K-17 glue consists
from 100 parts (by weight) MF-17 resin, 7 - 22 parts of a 10% aqueous solution of oxalic acid, 6-8 parts of wood flour.
can be cured both when heated and at normal temperature (only in the presence of a hardener).
Polyamides
hard translucent and opaque plastics that soften at temperature 150-180°C. They are distinguished by high chemical resistance, strength, resistance to friction, and elasticity. Polyamides do not ignite well, burn with a bluish flame, emitting the smell of burnt bone.
Proteins such as silk, which were replaced by nylon, are also polyamides.
Structure of polyamides
A distinctive feature of polyamides is the presence of a repeating amide group in the main molecular chain–C(O)–NH–. A distinction is made between aliphatic and aromatic polyamides. Polyamides are known that contain both aliphatic and aromatic fragments in the main chain.
Macromolecules of polyamides consist of flexible methylene chains and polar amide groups regularly located along the chain.
acetic acid amide (acetamide)
Amides are functional derivatives of carboxylic acids in which the hydroxyl –OH in the carboxyl group –COOH is replaced by an amino group –NH2.
Methods for producing polyamides
1. polycondensation (this reaction is called polyamidation) dicarboxylic acids (or their diesters)
and diamines.
Polycondensation is carried out mainly in a melt, less often in a solution of a high-boiling solvent or in a solid phase.
To obtain high molecular weight polyamides from dicarboxylic acids and diamines, polyamidation is carried out at equimolar
ratios of starting substances.
In this way, polyamides are obtained for the production of anide-type fibers (NYLON).
2. Polycondensation of diamines, dinitriles and water in the presence of catalysts. For example, oxygen compounds of phosphorus and boron, in particular mixtures of phosphorous and boric acids.
The process is carried out at 260-300 °C. First, under pressure, periodically releasing the released ammonia from the reaction zone. Finish at atmospheric pressure.
Nitriles are organic compounds of the general formula R-C≡N, formally derivatives of hydrocyanic acid HC≡N.
3. Polymerization of lactam amino acids.Mainly caprolactam. The process is carried out in the presence of water, alcohols, acids, bases and other substances that promote ring opening, or in the presence of catalysts, in a solution or melt at high temperature.
caprolactam
Lactam - cyclic amide
This is how nylon and enanth are obtained.
Getting nylon
Hydrolysis of caprolactam
Polycondensation
NH2 -(CH2) 5 - COOH + NH2 -(CH2) 5 - COOH + ... →
NH2 -(CH2) 5 - CO - NH -(CH2) 5 - CO - ... + nH2 O Simplified diagram
In industry it is obtained from caprolactam. The process is carried out in the presence of water, which plays the role of an activator, at a temperature of 240-270 ° C and a pressure of 15-20 kgf/cm2 in a nitrogen atmosphere.
The polymer is formed due to the interaction amino - and carboxyl groups of the molecules of the starting substances or due to the connection of open lactam molecules.
To produce polyamides with stable properties and regulate their molecular weight, processes are often carried out in the presence of molecular weight regulators - most often acetic acid.
They attach to the reactive end groups of the growing chain and block them, stopping further growth of the molecules.
In the names of aliphatic polyamides after the word “polyamide” (in foreign literature - "nylon") put numbers indicating the number of carbon atoms in the substances used for the synthesis of polyamide.
Polyamide based hexamethylenediamide and adipic
acid is called polyamide-6,6, or nylon-6,6
the first digit shows the number of carbon atoms in the diamine, the second- in dicarboxylic acid.
Material for a chemistry lesson in 11th grade
UMK O.S. Gabrielyan
- POLYMERS (from poly... and Greek meros - share, part), substances whose molecules (macromolecules) consist of a large number of repeating units; The molecular weight of polymers can vary from several thousand to many millions.
- The term “polymers” was introduced by J. Ya. Berzelius in 1833.
- Based on their origin, polymers are divided into natural, or biopolymers (e.g. proteins, nucleic acids, natural rubber), and synthetic(e.g. polyethylene, polyamides, epoxy resins) obtained by polymerization and polycondensation methods. Based on the shape of the molecules, they are distinguished linear, branched And mesh polymers, by nature - organic, organoelement, inorganic polymers.
- According to their structure, macromolecules are divided into linear, schematically designated -A-A-A-A-A-, (for example, natural rubber); branched having side branches (for example, amylopectin); And mesh or cross-linked, if adjacent macromolecules are connected by chemical cross-links (for example, cured epoxy resins). Highly cross-linked polymers are insoluble, infusible and incapable of highly elastic deformations.
- The reaction of formation of a polymer from a monomer is called polymerization. During polymerization, a substance can change from a gaseous or liquid state to a very thick liquid or solid state. The polymerization reaction is not accompanied by the elimination of any low molecular weight by-products. During polymerization, the polymer and monomer are characterized by the same elemental composition.
- n CH 2 = CH → (- CH 2 – CH-) n
propylene polypropylene
The expression in brackets is called the Structural Unit, and the number n in the polymer formula is the degree of polymerization.
- In addition to the polymerization reaction, polymers can be obtained polycondensation- a reaction in which a rearrangement of polymer atoms occurs and water or other low-molecular substances are released from the reaction sphere.
- n C 6 H 12 O 6 → (- C 6 H 10 O 5 -) n + H 2 O
glucose polysaccharide
- Linear and branched polymers form a class thermoplastic polymers or thermoplastics, and spatial - class thermosetting polymers or thermosets.
Polyamides- high-molecular compounds related to heterochain polymers, the main chain of which contains amide bonds through which monomeric residues are connected to each other. An example of polyamides is nylon. Therefore, let’s look at polyamides using polymers and nylon as examples.
Polymers
Polymers are chemical compounds with a high mol. mass (from several thousand to many millions), the molecules of which (macromolecules) consist of a large number of repeating groups (monomer units). The atoms that make up macromolecules are connected to each other by forces of principal and (or) coordination valences.
Classification of polymers
Based on their origin, polymers are divided into natural (biopolymers), for example proteins, nucleic acids, natural resins, and synthetic, for example polyethylene, polypropylene, phenol-formaldehyde resins. Atoms or atomic groups can be located in a macromolecule in the form of: an open chain or an elongated sequence of cycles (linear polymers, for example natural rubber); branched chains (branched polymers, such as amylopectin), three-dimensional networks (cross-linked polymers, such as cured epoxy resins). Polymers whose molecules consist of identical monomer units are called homopolymers (for example, polyvinyl chloride, polycaproamide, cellulose).
Macromolecules of the same chemical composition can be built from units of different spatial configurations. If macromolecules consist of the same stereoisomers or of different stereoisomers alternating in the chain at a certain periodicity, the polymers are called stereoregular.
Polymers whose macromolecules contain several types of monomer units are called copolymers. Copolymers in which units of each type form sufficiently long continuous sequences that replace each other within the macromolecule are called block copolymers. One or more chains of another structure can be attached to the internal (non-terminal) links of a macromolecule of one chemical structure. Such copolymers are called graft copolymers.
Polymers in which each or some stereoisomers of a unit form sufficiently long continuous sequences that replace each other within one macromolecule are called stereoblock copolymers. Depending on the composition of the main (main) chain, polymers are divided into: heterochain, the main chain of which contains atoms of various elements, most often carbon, nitrogen, silicon, phosphorus, and homochain, the main chain of which is built from identical atoms. Of the homochain polymers, the most common are carbon chain polymers, the main chains of which consist only of carbon atoms, for example polyethylene, polymethyl methacrylate, polytetrafluoroethylene. Examples of heterochain polymers are polyesters (polyethylene terephthalate, polycarbonates), polyamides, urea-formaldehyde resins, proteins, and some organosilicon polymers. Polymers whose macromolecules, along with hydrocarbon groups, contain atoms of inorganogenic elements are called organoelement. A separate group of polymers is formed by inorganic polymers, for example plastic sulfur and polyphosphonitrile chloride.
Properties and most important characteristics of polymers
Linear polymers have a specific set of physicochemical and mechanical properties. The most important of these properties: the ability to form high-strength anisotropic highly oriented fibers and films, the ability to undergo large, long-term reversible deformations; the ability to swell in a highly elastic state before dissolving; high viscosity of solutions. This set of properties is due to the high molecular weight, chain structure, and flexibility of macromolecules. When moving from linear chains to branched, sparse three-dimensional networks and, finally, to dense mesh structures, this set of properties becomes less and less pronounced. Highly cross-linked polymers are insoluble, infusible and incapable of highly elastic deformations.
Polymers can exist in crystalline and amorphous states. A necessary condition for crystallization is the regularity of sufficiently long sections of the macromolecule. In crystalline polymers, various supramolecular structures (fibrils, spherulites, single crystals) can appear, the type of which largely determines the properties of the polymer material. Supramolecular structures in non-crystallized (amorphous) polymers are less pronounced than in crystalline ones.
Non-crystallized polymers can exist in three physical states: glassy, highly elastic and viscous. Polymers with a low (below room) temperature of transition from a glassy to a highly elastic state are called elastomers, while those with a high temperature are called plastics. Depending on the chemical composition, structure and relative arrangement of macromolecules, the properties of polymers can vary within very wide limits. Thus, 1,4.-cispolybutadiene, built from flexible hydrocarbon chains, at a temperature of about 20 ° C is an elastic material, which at a temperature of -60 ° C transforms into a glassy state; polymethyl methacrylate, built from more rigid chains, at a temperature of about 20 ° C is a solid glassy product that turns into a highly elastic state only at 100 ° C. Cellulose, a polymer with very rigid chains connected by intermolecular hydrogen bonds, generally cannot exist in a highly elastic state before its decomposition temperature. Large differences in the properties of polymers can be observed even if the differences in the structure of macromolecules are, at first glance, small. Thus, stereoregular polystyrene is a crystalline substance with a melting point of about 235 °C, while non-stereoregular polystyrene is not able to crystallize at all and softens at a temperature of about 80 °C.
Polymers can enter into the following main types of reactions: the formation of chemical bonds between macromolecules (so-called cross-linking), for example, during the vulcanization of rubbers and tanning of leather; decomposition of macromolecules into separate, shorter fragments, reactions of side functional groups of polymers with low molecular weight substances that do not affect the main chain (so-called polymer-analogous transformations); intramolecular reactions occurring between functional groups of one macromolecule, for example intramolecular cyclization. Cross-linking often occurs simultaneously with destruction. An example of polymer-analogous transformations is the saponification of polytyl acetate, leading to the formation of polyvinyl alcohol. The rate of reactions of polymers with low molecular weight substances is often limited by the rate of diffusion of the latter into the polymer phase. This is most obvious in the case of cross-linked polymers. The rate of interaction of macromolecules with low-molecular substances often significantly depends on the nature and location of neighboring units relative to the reacting unit. The same applies to intramolecular reactions between functional groups belonging to the same chain.
