TOPIC 15 Paper (Note)

7/29/2019 TOPIC 15 Paper (Note)

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SCE3103 Exploring Materials

TOPIC 15 NATURAL MATERIALS- PAPER

Synopsis

We use many products made from paper. In this topic you will learn about different typesof paper, their properties, the process of making paper and the uses of paper in our dailylife.

Learning Outcomes

1. State the types of paper

2. State the properties of paper

3. Explain the process of making paper4. State the uses of paper in our daily life

OVERVIEW

Figure 15.1 Overview of content

CONTENT

The word paper derives from the Greek term for the ancient Egyptian writing material

called papyrus, which was formed from beaten strips of papyrus plants. Paper is thinmaterial mainly used for writing upon, printing upon or packaging.

15.1 Types of paper

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http://en.wikipedia.org/wiki/Ancient_Egypthttp://en.wikipedia.org/wiki/Papyrushttp://en.wikipedia.org/wiki/Papyrushttp://en.wikipedia.org/wiki/Cyperus_papyrushttp://en.wikipedia.org/wiki/Ancient_Egypthttp://en.wikipedia.org/wiki/Papyrushttp://en.wikipedia.org/wiki/Cyperus_papyrus


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Paper is a material that can be obtained in various types that differ in thickness andweight. Some types of paper include:

Bank paper

Book paper Inkjet paper pH indicator paper Photographic paper Plain paper Recycled paper Rice paper Paper towels Wall paper Wax paper Sand paper Coated paper (glossy and matt surface) Plain paper Newsprint

15.2 Properties of Paper

We use paper everyday. Its usefulness is due to its unique properties such as:

Basis Weight (GSM)

Brightness, Whiteness and Colour

Dimensional Stability

Folding Endurance (Double Folds)

Formation

Gloss

Machine and Cross Direction

Moisture

Opacity

Porosity

Sizing / Cobb

Smoothness

Stiffness

Stretch (Elongation) Tearing Resistance

Temperature and Humidity: Conditioning of Paper

Thickness

Wax Pick No. (Surface Strength)

Wire side and Felt side

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http://www.biltpaper.com/atoz2.asp#1http://www.biltpaper.com/atoz2.asp#2http://www.biltpaper.com/atoz2.asp#4http://www.biltpaper.com/atoz2.asp#5http://www.biltpaper.com/atoz2.asp#6http://www.biltpaper.com/atoz2.asp#7http://www.biltpaper.com/atoz2.asp#8http://www.biltpaper.com/atoz2.asp#9http://www.biltpaper.com/atoz2.asp#10http://www.biltpaper.com/atoz2.asp#11http://www.biltpaper.com/atoz2.asp#12http://www.biltpaper.com/atoz2.asp#13http://www.biltpaper.com/atoz2.asp#14http://www.biltpaper.com/atoz2.asp#15http://www.biltpaper.com/atoz2.asp#16http://www.biltpaper.com/atoz2.asp#17http://www.biltpaper.com/atoz2.asp#18http://www.biltpaper.com/atoz2.asp#19http://www.biltpaper.com/atoz2.asp#20http://www.biltpaper.com/atoz2.asp#1http://www.biltpaper.com/atoz2.asp#2http://www.biltpaper.com/atoz2.asp#4http://www.biltpaper.com/atoz2.asp#5http://www.biltpaper.com/atoz2.asp#6http://www.biltpaper.com/atoz2.asp#7http://www.biltpaper.com/atoz2.asp#8http://www.biltpaper.com/atoz2.asp#9http://www.biltpaper.com/atoz2.asp#10http://www.biltpaper.com/atoz2.asp#11http://www.biltpaper.com/atoz2.asp#12http://www.biltpaper.com/atoz2.asp#13http://www.biltpaper.com/atoz2.asp#14http://www.biltpaper.com/atoz2.asp#15http://www.biltpaper.com/atoz2.asp#16http://www.biltpaper.com/atoz2.asp#17http://www.biltpaper.com/atoz2.asp#18http://www.biltpaper.com/atoz2.asp#19http://www.biltpaper.com/atoz2.asp#20


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Making Notes (2 hours)

To get a better understanding of each of the properties of paperlisted above, read the article in the following website:http://www.biltpaper.com/atoz2.asp .Make short notes on each of the properties of paper.

15.3 Process of making paper

Paper is produced by pressing together moist fibers, typically vegetable fibers composedofcellulose, which are held together by hydrogen bonds, and drying them into flexiblesheets. While the fibers used are usually natural in origin, a wide variety of syntheticfibers, such as polypropylene and polyethylene, may be incorporated into paper as away of imparting desirable physical properties. The most common source of these kindsof fibers is wood pulpfrom pulpwoodtrees, largely softwoods and hardwoods, such asspruce and aspen respectively. Othervegetable fibermaterials including those ofcotton,hemp, linen, andricemay be used.

The steps in the process of making paper are:

Fiber processing / pulping using chemical pulping or mechanical pulping

Adding additives Drying Finishing

Fiber processing/pulping

Wood or plant cell walls are composed of fibers bound together. During pulping, thesefibers are separated from each other and carbohydrate surfaces, primarily cellulose orhemi-cellulose are exposed. Hydrogen bonding between these carbohydrate surfacesgives paper its strength. Fibers can be separated chemically, mechanically, or via acombination of the two.

Chemical pulping

The purpose of a chemical pulping process is to break down the chemical structure oflignin and render it soluble in the cooking liquor, so that it may be washed from thecellulose fibers. Because lignin holds the plant cells together, chemical pulping frees thefibers and makes pulp. The pulp must be bleached to produce white paper for printing,painting and writing. Chemical pulps tend to cost more than mechanical pulps, largelydue to the low yield, 40-50% of the original wood. Since the process preserves fiber

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http://www.biltpaper.com/atoz2.asphttp://en.wikipedia.org/wiki/Fiberhttp://en.wikipedia.org/wiki/Cellulosehttp://en.wikipedia.org/wiki/Cellulosehttp://en.wikipedia.org/wiki/Cellulosehttp://en.wikipedia.org/wiki/Wood_pulphttp://en.wikipedia.org/wiki/Wood_pulphttp://en.wikipedia.org/wiki/Pulpwoodhttp://en.wikipedia.org/wiki/Pulpwoodhttp://en.wikipedia.org/wiki/Softwoodhttp://en.wikipedia.org/wiki/Hardwoodhttp://en.wikipedia.org/wiki/Sprucehttp://en.wikipedia.org/wiki/Aspenhttp://en.wikipedia.org/wiki/Fiber_crophttp://en.wikipedia.org/wiki/Cottonhttp://en.wikipedia.org/wiki/Hemphttp://en.wikipedia.org/wiki/Linenhttp://en.wikipedia.org/wiki/Ricehttp://en.wikipedia.org/wiki/Ricehttp://en.wikipedia.org/wiki/Ricehttp://en.wikipedia.org/wiki/Woodhttp://en.wikipedia.org/wiki/Carbohydratehttp://en.wikipedia.org/wiki/Carbohydratehttp://en.wikipedia.org/wiki/Ligninhttp://en.wikipedia.org/wiki/Cellulosehttp://en.wikipedia.org/wiki/Printinghttp://en.wikipedia.org/wiki/Writinghttp://www.biltpaper.com/atoz2.asphttp://en.wikipedia.org/wiki/Fiberhttp://en.wikipedia.org/wiki/Cellulosehttp://en.wikipedia.org/wiki/Wood_pulphttp://en.wikipedia.org/wiki/Pulpwoodhttp://en.wikipedia.org/wiki/Softwoodhttp://en.wikipedia.org/wiki/Hardwoodhttp://en.wikipedia.org/wiki/Sprucehttp://en.wikipedia.org/wiki/Aspenhttp://en.wikipedia.org/wiki/Fiber_crophttp://en.wikipedia.org/wiki/Cottonhttp://en.wikipedia.org/wiki/Hemphttp://en.wikipedia.org/wiki/Linenhttp://en.wikipedia.org/wiki/Ricehttp://en.wikipedia.org/wiki/Woodhttp://en.wikipedia.org/wiki/Carbohydratehttp://en.wikipedia.org/wiki/Ligninhttp://en.wikipedia.org/wiki/Cellulosehttp://en.wikipedia.org/wiki/Printinghttp://en.wikipedia.org/wiki/Writing


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length, however, chemical pulps tend to make stronger paper. Another advantage ofchemical pulping is that the majority of the heat and electricity needed to run the processis produced by burning the lignin removed during pulping.

Mechanical pulping

There are two major mechanical pulps, thermomechanical pulp (TMP) and mechanicalpulp. The latter is known in the USA as groundwood pulp.In the TMP process, wood is chipped and then fed into large steam-heated refinerswhere the chips are squeezed and fiberised between two steel discs. In the groundwoodprocess, debarked logs are fed into grinders where they are pressed against rotatingstones and fiberised. Mechanical pulping does not remove the lignin, so the yield is veryhigh, more than 95%, but also causes paper made from this pulp to yellow and becomebrittle over time. Mechanical pulps have rather short fiber lengths and produce weakpaper. Although large amounts of electrical energy are required to produce mechanicalpulp, it costs less than chemical pulp.

Additives

Besides the fibers, pulps may contain fillers such as chalk or china clay, which improvethe characteristics of the paper for printing or writing. Additives for sizing purposes maybe mixed into the pulp and/or applied to the paper web later in the manufacturingprocess. The purpose of sizing is to establish the correct level of surface absorbency tosuit the ink or paint.

Drying

After the paper web is produced, the water must be removed from it in order to create ausable product. This is accomplished through pressing and drying. The methods of

doing so vary between the different processes used to make paper, but the conceptsremain the same. Pressing the sheet removes the water by force. Once the water isforced from the sheet, another absorbent material must be used to collect this water. Ona paper machine this is called a felt. When making paper by hand, a blotter sheet isused. Drying involves using air and or heat to remove water from the paper sheet.In the earliest days of papermaking this was done by hanging the paper sheets likelaundry. In more modern times, various forms of heated drying mechanisms are used.The most common is the steam-heated can dryer. These dryer cans heat totemperatures above 200F (93C) and are used in long sequences of more than 40cans. The heat produced by these can easily dry the paper to less than 6% moisture.

Finishing

The paper may then undergo sizing to alter its physical properties for use in variousapplications. Paper at this point is uncoated. Coated paper has a thin layer of materialsuch as china clay applied to one or both sides in order to create a surface more suitablefor high-resolution half-tone screens. Coated or uncoated papers may have theirsurfaces polished by calendering. Coated papers are divided into matt, semi-matt or silk,and gloss.

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The paper is then fed onto reels if it is to be used on web printing presses, or cut intosheets for other printing processes or other purposes. The fibers in the paper basicallyrun in the machine direction. Sheets are usually cut "long-grain", i.e. with the grainparallel to the longer dimension of the sheet. All paper produced by Fourdrinier-typemachines is wove paper, i.e. the wire mesh that transports the web leaves a pattern thathas the same density along the paper grain and across the grain. Wove paper does not

exhibit "laidlines", which are small regular lines left behind on paper when it washandmade in a mould made from rows of metal wires or bamboo. Handmade papersimilarly exhibits "deckle edges", or rough and feathery borders.

15.4 Uses of paper

Paper is a versatile material with many uses. Whilst the most common is for writing andprinting upon, it is also widely used as a packaging material, in many cleaning products,and in a number of industrial and construction processes, and occasionally as a food

ingredient, particularly in Asian cultures.

Paper can be produced with a wide variety of properties, depending on its intended use,such as:

To write or print on: the piece of paper becomes a document; this may be forkeeping a record (or in the case of printing from a computer or copying fromanother paper: an additional record) and for communication.

To represent a value: paper money, bank note, cheque, voucher, ticket

For entertainment: book, magazine, newspaper, art

For packaging: corrugated box, paper bag, envelope, wrapping tissue,

wallpaper For cleaning : toilet paper, handkerchiefs, paper towels, facial tissue

For construction : paper Mache, origami, quiling, paper engineering, clothing

Other uses: sandpaper, blotting paper, litmus paper, universal indicator paper,paper chromatography, electrical insulation paper, filter paper

Figure 15.4 Uses of paper(Source: http://images.google.com)

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http://en.wikipedia.org/wiki/Packaginghttp://en.wikipedia.org/wiki/Cleaninghttp://en.wikipedia.org/wiki/Edible_paperhttp://en.wikipedia.org/wiki/Edible_paperhttp://en.wikipedia.org/wiki/Edible_paperhttp://images.google.com/imgres?imgurl=http://www.misr-italia.com/images/idro_sample.jpg&imgrefurl=http://www.misr-italia.com/idro.html&usg=__s0mlHX5Smy2ABch_gO0CU5iymKI=&h=300&w=300&sz=55&hl=en&start=43&tbnid=Z1mK-qy9l1_XQM:&tbnh=116&tbnw=116&prev=/images%3Fq%3Dtypes%2Bof%2Bpaper%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DN%26start%3D40http://images.google.com/imgres?imgurl=http://blog.craftzine.com/tissue.jpg&imgrefurl=http://blog.craftzine.com/archive/2007/09/acidfree_tissue_paper.html&usg=__MBMAuM33pIO4cS41CR997_6yLTE=&h=400&w=400&sz=64&hl=en&start=3&tbnid=JKNOVQkWSB0q_M:&tbnh=124&tbnw=124&prev=/images%3Fq%3Dtissue%2Bpaper%26gbv%3D2%26hl%3Den%26sa%3DGhttp://images.google.com/imgres?imgurl=http://img.alibaba.com/photo/104907294/Copy_Paper.jpg&imgrefurl=http://www.alibaba.com/product/id105235084-104907294-0/Copy_Paper.html&usg=__jbuENNsWDtVZDUeRnJ-YAPTpIvE=&h=450&w=600&sz=40&hl=en&start=160&tbnid=8WHnCbsBafPFmM:&tbnh=101&tbnw=135&prev=/images%3Fq%3Dpaper%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DN%26start%3D140http://images.google.com/imgres?imgurl=http://www.germes-online.com/direct/dbimage/50258655/Paper_Tea_Cups.jpg&imgrefurl=http://www.germes-online.com/catalog/54/56/1100/paper_cups_plates_food_trays.html&usg=__N1InzFbunJSKcMKhlYfKQ3aPVxY=&h=360&w=360&sz=16&hl=en&start=7&tbnid=FwgeVI_mWpndIM:&tbnh=121&tbnw=121&prev=/images%3Fq%3Dpaper%26gbv%3D2%26hl%3Den%26sa%3DGhttp://en.wikipedia.org/wiki/Packaginghttp://en.wikipedia.org/wiki/Cleaninghttp://en.wikipedia.org/wiki/Edible_paperhttp://en.wikipedia.org/wiki/Edible_paper


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Exercise (2 hours)

Access the internet to gather information and to compare and contrast theproperties of different types of paper and their uses in daily life.

Thinking (10 hours)

We can reuse paper by recycling it. Make your own recycled paper. Go to theinternet for suggestions on how to make recycled paper. This websitehttp://www.recyclenow.com/why_recycling_matters/how_is_it_recycled/paper/ may be helpful. Create a useful item using the recycled paper you havemade. Organise a mini science exhibition to present the process of recyclingpaper and the products made from the recycled paper. Keep a photograph

journal of the exhibition.

At the end of the activity, answer the following questions:

What have you learnt from this activity?

Which part of the primary science curriculum teaches thistopic on paper?

Discuss how you can use this activity in your teaching andlearning.

What was the role of the teacher in this activity?

References

http://en.wikipedia.org/wiki/Paper(paper)

http://www.writersservices.com/wbs/care_history_paper.htm(History of paper making)

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http://www.recyclenow.com/why_recycling_matters/how_is_it_recycled/paper/http://www.recyclenow.com/why_recycling_matters/how_is_it_recycled/paper/http://en.wikipedia.org/wiki/Paperhttp://www.writersservices.com/wbs/care_history_paper.htmhttp://www.recyclenow.com/why_recycling_matters/how_is_it_recycled/paper/http://www.recyclenow.com/why_recycling_matters/how_is_it_recycled/paper/http://en.wikipedia.org/wiki/Paperhttp://www.writersservices.com/wbs/care_history_paper.htm


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http://www.writersservices.com/wbs/care_storing_books.htm(how to store books)

http://www.biltpaper.com/atoz2.asp(properties of paper)

http://www.recyclenow.com/why_recycling_matters/how_is_it_recycled/paper/(recycling of paper)

http://www.paperonweb.com/pmake.htm (processing paper)

http://www.geocities.com/kirktayl/(how to organise a science exhibition)

http://www.paperonweb.com/density.htm (properties of paper)

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http://www.writersservices.com/wbs/care_storing_books.htmhttp://www.biltpaper.com/atoz2.asphttp://www.recyclenow.com/why_recycling_matters/how_is_it_recycled/paper/http://www.paperonweb.com/pmake.htmhttp://www.paperonweb.com/pmake.htmhttp://www.geocities.com/kirktayl/http://www.paperonweb.com/density.htmhttp://www.writersservices.com/wbs/care_storing_books.htmhttp://www.biltpaper.com/atoz2.asphttp://www.recyclenow.com/why_recycling_matters/how_is_it_recycled/paper/http://www.paperonweb.com/pmake.htmhttp://www.geocities.com/kirktayl/http://www.paperonweb.com/density.htm

TOPIC 15 Paper (Note)

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