Lang's Rose Role (Part 3 and counting ...)
Funny how he comes to research a topic. You go and getting some reading sources information and soon a book falls into your hands and it turns out that refuting data is considered a safe, clear and concrete. This is what happened to me "Properties of Paper: An Introduction" , published by TAPPI (Industry Technology Association of the Pulp and Paper, for its acronym in English), authors William E. Scott, James C. Abbott and Stanley Trosset, a fantastic book, even when directed to the industrial production of paper in the United States, which leaves out certain uses art and craft of paper.
Such new information Incomplete places, I am forced to talk more about the nature of paper manufacturing.
We have said that the main source of raw material for industrial production of wood pulp is the tree. We also saw that along with other elements coexist cellulose in plant cells, such as Hemilcelulosa and lignin. However, reading this book I learned that the role of lignin in the plant is the bonding between the fibers and its concentration increases in the outer layers of cells in a plant, contrary to what we said in the last entry . Just need to remove the lignin to release cellulose fibers in a solution homogeneous, since it binds to the outer walls of the fibers and isolation from the other, hindering the formation of contact points between pure cellulose fibers (which are bringing about the "bond" or density of the paper.) Lignin is a complex structure and variable, is insoluble in water but can be soluble in certain acid solutions.
as practical information for those wishing to cook their own flesh, an agent that dissolves the lignin (not too efficient but it serves) is the popular caustic soda in water. Its efficiency improves in the presence of high temperatures and high pressure steam (But do a pressure cooker for a caustic solution can be very dangerous!). Do not worry about the cell, it resists almost all known chemicals except some very strong acids.
The other component, Hemilcelulosa, is a polymer similar to cellulose but with slightly different molecular compositions, is important in the role because it stimulates the formation of fiber-fiber contacts and absorption capacity water, however, does not withstand the process of removing lignin.
So if you ask me, I would say that if they want to make paper at home, forget about the wood of the tree and look for a plant with low concentrations of lignin and fibers too long (this leaves out the cotton) for otherwise the paper will be too strong (as cloth) and difficult bending (do not forget that the mark of a fold is given by the fracture of the fibers).
This is also the fact that paper production has become an extremely polluting process only by the use of chemicals in the extraction of lignin, and this has been like to use cheap and abundant materials as the wood of trees. Is everyone's responsibility to minimize the use of paper obtained by these means.
Within the methods exist to generate purely mechanical pulp (such as ball mills or disc refiners), equivalent to 10 to 15% of world production, its disadvantages are difficulty achieve a uniform and homogeneous pulp, excessive breakage and damage the fibers and rapid aging, so they are used in the manufacture of newsprint, catalogs, mild and temporary.
The lignin gives the pulp and paper color characteristic brown newsprint or newspaper. It must also understand that it is not possible to remove all the lignin in the wood, so all the pulp from that source has a characteristic brown color, the paper called kraft of that color, actually corresponds to a chemical process pure (a process that actually has that name), just has not gone through the stage of bleaching.
And speaking of contamination throughout the production process of the pulp is extremely consumer of fresh water, and while great strides have been developed in the reuse of this and chemicals caustic, is far from reasonable for the current state of nature, everything leads us to try to minimize the paper usage in our daily lives and to respect and love the role we have in hand, for the cost and sacrifice has meant to produce.
Paper Properties
Well, I finally feel that we can enter the field of physical and structural differences between different types of paper. The main properties of the paper is divided into structural and mechanical. In the next posts will talk about each.
structural properties are:
Weight Training
Thickness Duplex
Directionality smoothness
Porosity
Weight
In industrial terms, Paper weight is measured in packets of a certain amount and certain standard sizes but different, which makes it very cumbersome and difficult any comparative analysis of their characteristics, therefore the International System of Units established the amount of mass contained in a sheet fixed surface, weight or value of grams per square meter (g/m2), as an index characterizing the role.
Typical values \u200b\u200bfor different kinds of paper are:
Training
training paper refers to the uniform distribution of fibers and other components across a sheet of paper is in the process of settling and creation of the pulp sheet which controls the distribution of material and its uniformity.
thickness
The thickness (or caliper) is a vital parameter but somewhat underestimated by designers and packers, who generally look for the paper thin as possible to their complex shapes, especially when using the box-pleating and technical design. There is a tendency to believe that the thickness of paper is worthless and does not affect the geometry and symmetry of a figure, nothing more wrong, especially when it comes to folding many layers together.
is clear that the number of layers to be folded together is related to the thickness of paper used. However, there is a physical limit that teaches us to gauge the real importance of the thickness of the role of folding a single sheet. To illustrate exaggerate the thickness of a paper and see how many layers of paper generated large concentric circles around the bend, the higher the number, the greater its diameter and higher paper remaining on the leaf.
The calculation of these diameters was made by a math student in the U.S. (now professor) called Britney Gallivan in December 2001, obtaining a series of numbers and a formula to calculate the length L required for a sheet t thick paper can be folded a number of n consecutive times:
For example, the thickness of a regular bond paper for your printer is 0.1 mm, suppose we want to turn this page over itself 10 times, just lose 55.036036 meters! only paper in the folds ... She managed to establish in 2005 a world record by folding a sheet over itself a number of 12 times (for the curious, our road would measure 880 meters, nearly a mile long)
regular thickness values \u200b\u200bfor different roles are given in the following table:
An important parameter is calculated by dividing the weight by the thickness of paper used, called the bulk density, very thin paper but high weight may be more resistant to tearing than others, usually in the compression step in the manufacture of paper when these differences are achieved. When we see the mechanical properties of paper talk more about it.
