A triangle is geometric figure which has three sides and adjacent to each side is an angle so the triangle has three sides and three angels. There are different types of triangles either a right angle triangle, isosceles triangle etc. An equilateral triangle is a triangle which has all three sides equal to each other. … Read more

Energy is the ability of any body to do some work. A work is said to be done if a force is applied on any body and it is made to move a certain distance in a direction. When work is done it is done on a certain body and the amount of work done … Read more

Upon cooling of the melt, 15-100 nano meter thick single crystals (folding crystallites) are formed which subsequently arrange themselves into larger, polyhedral) structures, so-called spherulites.    Spherulites are centrally symmetric superstructures consisting of many single crystals with their macrornolecules preferentially arranged tangentially to the radius. Spherulites, in general, have a diameter between 0.1-1.0 mm. Typical … Read more

Bimodal polymers are a special group of polymeric materials, which, in principle, consist of two intimately mixed polymers of different molecular weight. With polyethylenes of different molecular weight as an example, show the bimodal effect on practical properties and on processing. Fractions in Polyethylenes (PE), with a molecular weight < 400 g/mol, tend to migrate … Read more

During the solidification process, some polymers are able to form an internal structure consisting of regular shapes with surfaces in an even arrangement. This internal arrangement of macromolecules is called the crystalline structure. Whether polymers are able to crystallize or not depends on their molecular structure. In general, the unbranched macromolecules with no or only … Read more

Crystallization adds a lot of important properties in a material which are not present in the amorphous polymers. Thus it is important to have crystalline polymers for different applications. The fraction of crystalline material in the polymer is called the degree of crystallinity. However, since the boundary between "crystalline" and "amorphous" is not well defined, … Read more

In order to be more useful for the costing of products and services, for cost control, and for a variety of other purposes, costs should be accumulated under three major classifications: by types of expense; by department or cost center; and by job, process, or service. Account classifications of costs by type of expense for … Read more

The experimental measurement of charge on one electron was made by R.A. Millikan, in 1909. The principle of experiment made by R.A. Millikan was that two metallic plates were set horizontally and parallel to each other. These were separated by a short distance. The upper plate had a small hole, at its center, and variable … Read more

Electricity is the name of flow of current, in normal routine current is produced when a charge flows from one point to the other point under the effect of some potential difference. This concept of generation of electricity was introduced by R.A. Millikan in his atomizer experiment in which some droplets of oil were dispersed … Read more

Electricity is a common term used to define the flow of charged particles. The rate of flow of charge is called electrical current and in some definitions the rate of flow of current is called electricity. At atomic level we have some atoms in which we have electrons and protons. The electrons are bound to … Read more

Computers today are one of the important things we are using. They have helped a lot in compiling a lot data which used to be in hard records. One of the uses or benefits of computers is that they are able to provide and retrieve information so quickly so they have increased the pace of … Read more

Cast film extrusion uses Vaccum box in its operational form. The vacuum box is used to ensure intimate contact between the molten polymer web and the casting roll. However vacuum box relies on a negative pressure, not a positive one, for pinning the web to the roll. A good designed vacuum box creates a true … Read more

The air knife is used to ensure intimate contact between the molten polymer web and the casting roll. As the polymer exits the die and contacts thee roll, an air stream from the air knife strikes the polymer. An air blower supplies air. The air velocity across the face of the knife should be equal. … Read more

In chill roll or cast film extrusion, the molten polymer is cast through a narrow slot die and drawn down and formed onto a rotating chill roll with the aid of a web forming device. One or more additional chill rolls can be provided fro improved film cooling and higher outputs. A heated roll can … Read more

The most important types of chain polymerization are radical polymerization, ionic polymerization, and insertion or coordination polymerization. Three steps characterize each method of polymerization. The start reaction or initiation, the growth reaction, and the termination reaction. The first reaction step, i.e. The initiation, is the formation of a reactive radical or ion9. This requires, in … Read more

In ionic polymerization, the activator is not a radical but an ion. Similar to radical polymerization, ionic polymerization is also a chain reaction. In the polymerization of styrene with tetrahydrofuran as the solvent and cumyl potassium as the initiator, the latter dissociates into a positive potassium ion and a negative cumyl ion. The potassium ion … Read more

Polyaddition reactions are similar to polycondensation reactions because they are also step reactions, however without splitting off low molecular weight by-products. The reaction is exothermic rather than endothermic and therefore cannot be stopped at will. Typical for polyaddition reaction is that individual atoms, usually H-atoms, wander from one monomer to another as the two monomers … Read more

A sharp melting point is common to all nylon homopolymers while some copolymers have broad melting point. Nylon 6 melts at about 150°C over glass transition point; it means about 428°F (22O°C). There is little softening of the resin until it actually melts. This provides the necessary strength at elevated temperatures and enables nylon to … Read more

Blocking is a common phenomenon encountered in plastic film rolls, one common reason for film blocking is winder tension, which may be overlooked unless the core cannot be removed from the journal. Conversely, if the tension is too loose the film may telescope off the core making further conversion impossible. Seasonal changes are an acute … Read more

The engine of any automobile car works through a mixture of air and fuel, only a small quantity of fuel is required to initiate the ignition process because the flash point of air is very high and that of fuel is very low thus a less amount of fuel is sufficient for the burning of … Read more