ÿþ<html> <head> <title>Cellulose</title> <script language="JavaScript"> <!-- This script and many more are available free online at --> <!-- The JavaScript Source!! http://javascript.internet.com --> <!-- Begin function Start(page) { OpenWin = this.open(page, "CtrlWindow", "height=520,width=700,left=120,top=120,scrollbars=yes"); } function Start_small(page) { OpenWin = this.open(page, "CtrlWindow", "height=400,width=400,left=120,top=120,scrollbars=yes,resizable=yes"); } // End --> </script> <link rel=stylesheet type="text/css" href="level1.css" media=screen> </head> <body bgcolor="ddff99"> <center> <img src="images/cellsign.gif" alt="Cellulose"> </center> <table> <tr> <td> <img src="images/cell05.gif" alt="Structure of Cellulose" > </td> <td> <a href="javascript:Start_small('models/cell3d.htm')"><img src="models/cell.jpg" border="0"></a><br> Click the picture to see a 3-d interactive version of cellulose. </td> </tr> </table> <br> <h2>Made by Nature</h2> <p> All kinds of plants - like carrots, apple trees, and flowers - make the polymer <em>CELLULOSE</em> (sell-you-low-s). Plants use cellulose to make their stems and branches and leaves strong. </p> <p> Cellulose makes tree trunks strong enough to hold up the tallest trees! We can even build tall houses out of wood. Wood is also used to make paper. Did you know that paper is mostly cellulose? </p> <h2>Cotton is Mostly Cellulose!</h2> <p> The cotton-ball part of the cotton plant has a <em>lot</em> of cellulose. <img src="images/cotboll.gif" height="75" align="left"> Cellulose makes great <a href="fiber.htm">fibers</a>. Thanks to cellulose, cotton fibers can be twisted into thread and woven into cloth. Cotton fibers are even found in some fancy kinds of paper, and that makes the paper feel more cloth-like. </p> <h2> Why is cellulose so strong? <br> Why does it make great fibers? </h2> <p> Let's find out by looking at what the polymer chains are like. </p> <table width="100%"> <tr> <td width="10%">&nbsp;</td> <td width="50%"> Cellulose chains are kind of like raw spaghetti: all stretched out and lined up next to each other. Imagine these sticks of spaghetti much, much longer, and stuck to each other, too. </td> <td width="*" valign="middle"> <img src="images/spagraw.gif" height="100" alt="a handful of stiff raw spaghetti"> </td> </tr> </table> <hr color=black> <h2>A Closer Look at Cellulose</h2> <p> Plants make cellulose from glucose, a simple <a href="javascript:Start('sugar.htm');">sugar</a>. Plants know how to connect the glucose monomers in a way that lets the chain stretch out, nice and straight. </p> <center> <table width="100%"><tr> <td style="vertical-align:top;text-align:center"> Monomer: Glucose<br> <img src="images/gluc_str.gif" alt="glucose structure"> </td> <td style="vertical-align:top;text-align:center"> Polymer: Cellulose<br> <img src="images/cellstr.gif" alt="cellulose structure"> <br>&nbsp;<br> <div style="font-size:80%"> <b>We left the C atoms (and most of the H's) out of this drawing to make it look nicer.<br> <a href="javascript:Start('orgdrwg.htm');"><b> Click here to learn more about drawing molecules like this.</a></div> </td> </tr> </table> </center> <p> When the chains lie next to each other, there are -OH groups in-between the chains. See them in blue? There are three -OH groups attached to each ring, and they can act like little magnets for each other. All these little magnets </p> <p> <img src="images/monoclip.gif" alt="Science Term" align="left" height="170"> The science term for this awesome sticky force (between chains of cellulose) is called <em>hydrogen bonding</em>. The "H" acts like the (+) end of a magnet, and the "O" acts like the (-) end. When they're close, they stick. If it was just a few hydrogen bonds, they could pull apart (like pulling apart two weak magnets). But when you add up a whole bunch of them on a long polymer chain, they make the material very stiff and strong!</p> <p style="color:red; text-align:center"> Click on the image below to see one way that cellulose chains can form hydrogen bonds. <br> <script language="JavaScript"> sys_img3090_click = new Image(); sys_img3090_click.src = "images/hbondcrp.gif"; </script> <img src="images/cellstr.gif" border="0" name="sys_img3090" onclick="document.sys_img3090.src=sys_img3090_click.src;"> </p> <hr color=black> <h2>More about Glucose</h2> <p> <img src="images/baker12.gif" align="right" alt="potatoes" height="150"> Glucose is used by plants and animals for energy. There's one problem - we can't digest cellulose! Plants can connect glucose monomers together in a different way, so that they twist all around and form a big globby polymer called <a href="starch.htm">starch</a>. (Potatoes make a lot of starch!) </p><p> Your body can digest the starch back down into glucose molecules, and then use the glucose for energy to run and jump and play and think! You've heard of carbos? Carbos (short for <em>carbohydrates</em>) are sugars and starches. <a href="starch.htm">Click here to learn more about starch.</a> <br> <a href="starlose.htm">Click here to learn more about how starch and cellulose differ.</a> </p><p> Even though we can't digest cellulose, it's still an important part of your diet. The cellulose fibers from vegetables and grains help to scrub out your intestines and keep them clean. <a href="javascript:Start('bran.htm')" >Click here for more about fiber in your diet.</a> </p> <p> To learn more about other polymers made by nature, <a href="natural.htm">click here</a>. </p> <!-- original cellulose code <embed src="models/cell.pdb" width = 300 height = 300 siny = 360 startspin=false display3d=spacefill align=right> <H1> <IMG SRC="images/cellsign.gif" alt="Cellulose"></H1> <p> <img src="images/cell05.gif"> <BR> Cellulose is one of many polymers found in <A HREF="natural.htm">nature</A>. Wood, paper, and cotton all contain cellulose. Cellulose is an excellent <A HREF="fiber.htm">fiber</A>. One way to tell this is by how straight and regular its shape is, especially in the 3-D model. Wood, cotton, and hemp rope are all made of fibrous cellulose. <BR><BR> Cellulose is made of repeat units of the monomer glucose - the same thing as sugar. Because cellulose is built out of a sugar monomer, it is called a polysaccharide. This is the same glucose which your body uses in order to live, but you can't digest it in the form of cellulose. Still it is an important part of your diet. The cellulose fibers from vegetables and grains kind of scrub out your intestines and keep them clean. <p> <CENTER> <img src="images/glucose.gif"> <embed src="models/glucose.pdb" width = 230 height = 230 siny = 360 startspin=false display3d=spacefill> <BR><BR> Now take a look at glucose in this diagram and in 3-D!</a> </CENTER> <A NAME="early"> <BR><BR> <BIG>Polymers Made From Cellulose </BIG> <TABLE bgcolor="c0ddff" align="right" cellpadding="10"> <TD> <CENTER> <IMG SRC="images/ryonpost.gif" alt="Saving Private Rayon - now playing at the Macroplex Cinema" border="0"> <BR><B><SMALL> NOW PLAYING<BR> at the Macroplex<BR> Cinema! </CENTER> </TD> </TABLE> <p>Not only is cellulose everywhere in nature, it was also used to make some of the first synthetic polymers like cellulose nitrate, cellulose acetate, and rayon. Forms of these polymers are still made and used today. <BR><BR> <A NAME="nitrate"> <EM>Cellulose nitrate</EM> - also called nitrous cellulose - was originally used to make <A HREF="plastic.htm#plastic">plastics</A> often used as imitation ivory. It ws also used to make motion picture film. But it was highly explosive and caused a lot of fires in movie theaters. This stuff is still around in a much safer form which is stil used for plastics and clear laquor coating for furniture, musical instruments and other wood objects. <BR><BR> <A NAME="acetate"> <EM>Cellulose acetate</EM> was what replaced cellulose nitrate in movie film. It is not explosive and is sitll used to make film negative, print film and clear plastic sheets. In the old days of movies it was often called celluloid, and this name is still used to refer to movie film, even though a lot of the release prints for movies are now made on more durable <A HREF="pet.htm">polyester</A>. Cellulose acetate is also used to make <A HREF="fiber.htm">fibers</A> for acetate fabric. <BR><BR> <A NAME ="rayon"> <EM>Rayon</EM> was originally a fiber made from cellulose nitrate. But like the plastic and film versions it was also very flammable. The new rayon - made from cellulose xanthate - is much safer and less flammable than the old stuff. Rayon is pretty popular for fabric since it has a lot of the qualities of natural plant fibers - which makes sense, since that's what it is made from. But it also has a smooth texture that makes it shiny like silk. One of the first uses of rayon was as an inexpensive replacement for silk. <P> <BIG> Another Polysaccharide </BIG> <P> A polysaccharide very similar to cellulose, is <A HREF="starch.htm">starch</A>. This is a form that people eat and can digest for energy. <p> --> Other polymers that are used as <a href="fiber.htm">fibers</a> include: <p> <ul> <dt><a href="polyeth.htm"><b>Polyethylene</b></a></dt> <dt><a href="polyprop.htm"><b>Polypropylene</b></a></dt> <dt><a href="nylon.htm"><b>Nylon</b></a></dt> <dt><a href="pet.htm"><b>Polyester</b></a></dt> <dt><a href="polyac.htm"><b>Polyacrylonitrile</b></a></dt> <dt><a href="polyure.htm"><b>Polyurethanes</b></a></dt> </ul> <p> <table cellpadding="6"> <tr> <td> <a href="kfloor2.htm"> <img src="arrow.gif" border="0"></a> </td> <td> <b> <a href="kfloor2.htm">Return to Kinds of Polymers </a> </td> </tr> </table> <table cellpadding="6"> <tr> <td> <a href="index.htm" target="_top"> <img src="arrow.gif" border="0"></a> </td> <td> <b> <a href="index.htm" target="_top">Return to Main Page</a> </td> </tr> </table> <center class="small"> <img src="hr.gif"><br><br> Copyright &copy; 2003 | <a href="http://pslc.ws" target="blank">Polymer Science Learning Center</a> | <a href="http://www.psrc.usm.edu/index.html" target="blank">Department of Polymer Science</a> | <a href="http://www.usm.edu/index.html" target="blank">University of Southern Mississippi</a> </center> </body> </html>