BioPlastics Lab
Abstract:
Polymers are used for many things, they help people live their lives, they hold things together, and do much more. To be effective however, polymers must be made specific to what they are being made for. The purpose of this lab is to find a recipe of polymer which will hold the most weight possible without breaking. To perform this experiment, a control recipe of a bio-plastic was created and then tested. From these results, a new bio-plastic recipe was created to outdo the previous one, and hold more weight than it did. Tests showed that After tests were completed, it was found that the more plasticizer a bio-plastic has, the stronger it will be, and that a bio-plastic will be stronger if it is air dried, rather than baked dry.
Introduction:
A monomer is a molecule, which when chemically bonded to other monomers, creates a polymer. Polymers are chains of monomers bonded, and held together by intermolecular forces. Polymers can be either natural (cotton, wood, proteins, etc) or synthetic (plastics, Styrofoam, etc.) General properties of polymers include having a generally low melting point, generally flexible, moderately durable, and being chemically nonreactive meaning polymers degrade slowly. Polymers are classified into two separate groups, homo-polymers, which are polymers made up of only one kind of monomer, and co-polymers, which are polymers made of multiple types of monomers.
Polysaccharide (starch) is a long chain of glucose molecules bonded together. They are usually made of two main ingredients, amylose, a polymer with a linear architecture, and amylopectin, a polymer with a branched architecture. The process by which polymers are made from monomers is called polymerization, and is a chemical reaction. Condensation polymerization is a specific form of polymerization where two molecules bond together resulting in another molecule being released from the reaction. An example of this could be when two glucose (sugar) molecules bond to each other resulting in the release of a molecule of water.
Polymers are generally amorphous, however can have a crystalline structure. The micro-structure of the polymer can show the properties of the polymer, and how it may act under certain conditions. For example, the shape of the micro-structure of the polymer can have an effect on the flexibility of the polymer. Polymers have three main structures, linear, which is a simple, one-stranded monomer chain, because this is a single strand, it is easy for this substance type to pack easier resulting in a more durable, higher melting point polymer. The second structure is branched, a monomer chain where small 'branches' will extend out of the main monomer chain, because of the branches, it is harder for the polymer strands to pack tightly resulting in a weaker, lower melting point polymer substance. Finally cross-linked, where each strand of monomers is connected to another through a branch of monomers, being the most durable, and with the highest melting point.
Similar to the micro-structure of a polymer, the length of each monomer chain affects the durability and flexibility of a polymer. The longer the monomer chain, the more flexible, durable, and higher the melting point the polymer will have. A plate of spaghetti can be used as an example of this. If a fork is dragged through two plates of spaghetti (one with long noodles and the other with short noodles), it will be harder for the fork to move through the plate with longer noodles as they will all become intertwined. The same is with polymers, the longer the monomer chain, the stronger the polymer will be.
To change characteristics of some polymers, molecules such as plasticizers can be added to the polymer. When a plasticizer is added to a polymer, it creates spaces between each monomer chain, this makes the polymer more flexible. Elastomers are a sub-classification of polymers, these polymers may bend out of shape when force is applied, then easily move back to the original position they were in, these types of polymers are rubber. Polymers also respond differently to heat. Some polymers, thermoplastics, can be heated and formed into new shapes as the monomer bonds will reform such as hot glue. This only can happen with linear or branched structured polymers. Another form of polymer, thermoset, can only be molded into a particular shape once; if this type of polymer is reheated, the polymer will not be re-molded as the bonds will not form again. This is only true with cross-linked structured polymers. An example of this would be two-part epoxy, once the bond is formed, it cannot be redone through reheating the polymer.
Methods:
*Wear safety goggles
*Use hot pads for hot surfaces
Original Methods:
Recipe for Starch Bio-plastic
Revised Methods:
Recipe for new starch bio-plastic (glycerin):
To Test the Strength of Each Polymer Recipe:
Results:
(Figure 1: Weight Test)
Table 1: Amount of weight taken to break different polymers
Drying Method
Original Recipe
Glycerin Recipe
Vinegar Recipe
Air dry 72 hours
1,120 grams
MAX
MAX
Bake 3 hours
990 grams
1,090 grams
890 grams
As seen above in Table 1, the original (or control) recipe which was air dried held 1,120 grams before breaking. When baked for 3 hours, the same recipe of polymer held 990 grams. The glycerin recipe, a new recipe made which used more glycerin and less vinegar, when air dried held over 1,500 grams. When baked the same polymer recipe held 1,090 grams. The third recipe created contained more vinegar and less glycerin. When set to air dry, it held over 1,500 grams, when baked it held 890 grams.
Discussion:
The purpose of this lab was to find a recipe of polymer which would hold the most weight possible without breaking. To perform this experiment, a control recipe of a bio-plastic was created and then tested. From these results, a new bio-plastic recipe was created to outdo the previous one, and hold more weight than it did. The original recipe air dried held 1,120 grams (as seen in table 1) and the same recipe baked held 990 grams. The results taken from the tests showed that polymers which were air-dried held more weight than those which were baked. This is true throughout all the testing done in this lab, each time one recipe was baked and the same one air dried, the recipe which was allowed to air dry held more weight than when baked. This could be because when the polymers are baked completely dry, they become more brittle than when they are set out and allowed time to dry slowly, staying stable.
The amount of glycerin and vinegar in the recipe were changed to bring about a different result than the original recipe presented. Glycerin acted as a plasticizer in the recipe, creating space between each monomer strand. The amount of this could be added to or lowered to bring about a different effect. The amount of vinegar in the recipe was also changed, vinegar acted as an acid in the recipe, working to cleave off the branches of branched monomer strands. When branches are taken off of the strand, it becomes easier for the monomer strands to compact tighter, making a more durable polymer. Adding in or lowering the amount of vinegar used in the recipe also brought about a different result.
A new recipe was made using more glycerin and less vinegar. This recipe proved to be better than the control recipe and held more weight. It would seem that the more plasticizer added to a polymer, the more durable it will become. Plasticizers move in-between the monomer strands and create space making the polymer more flexible and in this case, durable. Many times when a substance has more give to it, it is able to hold more weight because the substance was able to stretch or bend when the weight became too much, substances without this 'give' will snap when the weight becomes too much, without first bending and stretching.
The third recipe made added more vinegar and less glycerin. Vinegar acted as the acid in the polymer, working to remove some of the branches protruding from the monomer strands, helping the polymer to pack more tightly, resulting in a more durable polymer. This polymer recipe held a very high amount of weight due to the compactness of the monomer strands, the previous recipe had 'give' to it but was less dense than it could have been, despite this, the polymer was able to hold high amounts of weight. This third recipe did not have as much 'give' to it, however it was very compact helping the polymer to be ale to hold more weight in general. It could be that making a polymer with high amounts of both plasticizer and acid would result in a very compact, but flexible poly which could hold more weight than any of the tests shown in this lab.
It is possible that a more precise measuring technique could have been used to perform these tests, to gain a more exact measurement of the amount of weight needed to break each polymer. However this would not seem to change the results in any way as the properties of each polymer (and the plasticizers and acid) where what were being tested, not the exact weight needed to break them.
Polymers are used for many things, they help people live their lives, they hold things together, and do much more. To be effective however, polymers must be made specific to what they are being made for. The purpose of this lab is to find a recipe of polymer which will hold the most weight possible without breaking. To perform this experiment, a control recipe of a bio-plastic was created and then tested. From these results, a new bio-plastic recipe was created to outdo the previous one, and hold more weight than it did. Tests showed that After tests were completed, it was found that the more plasticizer a bio-plastic has, the stronger it will be, and that a bio-plastic will be stronger if it is air dried, rather than baked dry.
Introduction:
A monomer is a molecule, which when chemically bonded to other monomers, creates a polymer. Polymers are chains of monomers bonded, and held together by intermolecular forces. Polymers can be either natural (cotton, wood, proteins, etc) or synthetic (plastics, Styrofoam, etc.) General properties of polymers include having a generally low melting point, generally flexible, moderately durable, and being chemically nonreactive meaning polymers degrade slowly. Polymers are classified into two separate groups, homo-polymers, which are polymers made up of only one kind of monomer, and co-polymers, which are polymers made of multiple types of monomers.
Polysaccharide (starch) is a long chain of glucose molecules bonded together. They are usually made of two main ingredients, amylose, a polymer with a linear architecture, and amylopectin, a polymer with a branched architecture. The process by which polymers are made from monomers is called polymerization, and is a chemical reaction. Condensation polymerization is a specific form of polymerization where two molecules bond together resulting in another molecule being released from the reaction. An example of this could be when two glucose (sugar) molecules bond to each other resulting in the release of a molecule of water.
Polymers are generally amorphous, however can have a crystalline structure. The micro-structure of the polymer can show the properties of the polymer, and how it may act under certain conditions. For example, the shape of the micro-structure of the polymer can have an effect on the flexibility of the polymer. Polymers have three main structures, linear, which is a simple, one-stranded monomer chain, because this is a single strand, it is easy for this substance type to pack easier resulting in a more durable, higher melting point polymer. The second structure is branched, a monomer chain where small 'branches' will extend out of the main monomer chain, because of the branches, it is harder for the polymer strands to pack tightly resulting in a weaker, lower melting point polymer substance. Finally cross-linked, where each strand of monomers is connected to another through a branch of monomers, being the most durable, and with the highest melting point.
Similar to the micro-structure of a polymer, the length of each monomer chain affects the durability and flexibility of a polymer. The longer the monomer chain, the more flexible, durable, and higher the melting point the polymer will have. A plate of spaghetti can be used as an example of this. If a fork is dragged through two plates of spaghetti (one with long noodles and the other with short noodles), it will be harder for the fork to move through the plate with longer noodles as they will all become intertwined. The same is with polymers, the longer the monomer chain, the stronger the polymer will be.
To change characteristics of some polymers, molecules such as plasticizers can be added to the polymer. When a plasticizer is added to a polymer, it creates spaces between each monomer chain, this makes the polymer more flexible. Elastomers are a sub-classification of polymers, these polymers may bend out of shape when force is applied, then easily move back to the original position they were in, these types of polymers are rubber. Polymers also respond differently to heat. Some polymers, thermoplastics, can be heated and formed into new shapes as the monomer bonds will reform such as hot glue. This only can happen with linear or branched structured polymers. Another form of polymer, thermoset, can only be molded into a particular shape once; if this type of polymer is reheated, the polymer will not be re-molded as the bonds will not form again. This is only true with cross-linked structured polymers. An example of this would be two-part epoxy, once the bond is formed, it cannot be redone through reheating the polymer.
Methods:
*Wear safety goggles
*Use hot pads for hot surfaces
Original Methods:
Recipe for Starch Bio-plastic
- Measure
60ml of cold water, 10g of starch, 5 ml of vinegar and 5 ml of
glycerin and combine in a 600 ml beaker. Mix thoroughly so that all
of the starch is dissolved.
- Place the beaker on a hot plate
set at around 165 °C and stir regularly. Continue heating and
stirring until the mixture begins to thicken. Once the mixture
begins to thicken increase the heat to around 230 °C and stir more
vigorously.
- Once the substance is very clear
and sticky remove from heat and transfer the substance into the
assigned mold.
- Let one half of the bio-plastic
dry at room temperature for 72 hours
- For the other half: Place in an
oven at 150°F for 2-4 hours.
Revised Methods:
Recipe for new starch bio-plastic (glycerin):
-
Measure 60ml of cold water, 10g of starch, 1.25 ml of
vinegar and 5 ml of glycerin and combine in a 600 ml beaker. Mix
thoroughly so that all of the starch is dissolved.
- Place the beaker on a
hot plate set at around 165 °C and stir regularly. Continue
heating and stirring until the mixture begins to thicken. Once the
mixture begins to thicken increase the heat to around 230 °C and
stir more vigorously.
- Once the substance is very clear
and sticky remove from heat and transfer the substance into the
assigned mold.
- Let one half of the bio-plastic
dry at room temperature for 72 hours
-
For the other half: Place in an oven at 150°F for 2-4
hours.
- Measure
60ml of cold water, 10g of starch, 5 ml of vinegar and 1.25 ml of
glycerin and combine in a 600 ml beaker. Mix thoroughly so that all
of the starch is dissolved.
- Place the beaker on a hot plate
set at around 165 °C and stir regularly. Continue heating and
stirring until the mixture begins to thicken. Once the mixture
begins to thicken increase the heat to around 230 °C and stir more
vigorously.
- Once the substance is very clear
and sticky remove from heat and transfer the substance into the
assigned mold.
- Let one half of the bio-plastic
dry at room temperature for 72 hours
-
For other half: Place in an oven at 150°F for 2-4
hours.
To Test the Strength of Each Polymer Recipe:
-
Place polymer on top of and in-between two hard
surfaces with around 2 feet of space below them.
-
Tie a string around the center of the polymer with a
loop at the end hanging in-between the two hard surfaces (see figure
1).
-
Begin hanging weights (in grams) onto the string until
the polymer breaks in half.
-
Record the amount of weight the polymer took before
breaking.
Results:
(Figure 1: Weight Test)
Table 1: Amount of weight taken to break different polymers
Drying Method
Original Recipe
Glycerin Recipe
Vinegar Recipe
Air dry 72 hours
1,120 grams
MAX
MAX
Bake 3 hours
990 grams
1,090 grams
890 grams
As seen above in Table 1, the original (or control) recipe which was air dried held 1,120 grams before breaking. When baked for 3 hours, the same recipe of polymer held 990 grams. The glycerin recipe, a new recipe made which used more glycerin and less vinegar, when air dried held over 1,500 grams. When baked the same polymer recipe held 1,090 grams. The third recipe created contained more vinegar and less glycerin. When set to air dry, it held over 1,500 grams, when baked it held 890 grams.
Discussion:
The purpose of this lab was to find a recipe of polymer which would hold the most weight possible without breaking. To perform this experiment, a control recipe of a bio-plastic was created and then tested. From these results, a new bio-plastic recipe was created to outdo the previous one, and hold more weight than it did. The original recipe air dried held 1,120 grams (as seen in table 1) and the same recipe baked held 990 grams. The results taken from the tests showed that polymers which were air-dried held more weight than those which were baked. This is true throughout all the testing done in this lab, each time one recipe was baked and the same one air dried, the recipe which was allowed to air dry held more weight than when baked. This could be because when the polymers are baked completely dry, they become more brittle than when they are set out and allowed time to dry slowly, staying stable.
The amount of glycerin and vinegar in the recipe were changed to bring about a different result than the original recipe presented. Glycerin acted as a plasticizer in the recipe, creating space between each monomer strand. The amount of this could be added to or lowered to bring about a different effect. The amount of vinegar in the recipe was also changed, vinegar acted as an acid in the recipe, working to cleave off the branches of branched monomer strands. When branches are taken off of the strand, it becomes easier for the monomer strands to compact tighter, making a more durable polymer. Adding in or lowering the amount of vinegar used in the recipe also brought about a different result.
A new recipe was made using more glycerin and less vinegar. This recipe proved to be better than the control recipe and held more weight. It would seem that the more plasticizer added to a polymer, the more durable it will become. Plasticizers move in-between the monomer strands and create space making the polymer more flexible and in this case, durable. Many times when a substance has more give to it, it is able to hold more weight because the substance was able to stretch or bend when the weight became too much, substances without this 'give' will snap when the weight becomes too much, without first bending and stretching.
The third recipe made added more vinegar and less glycerin. Vinegar acted as the acid in the polymer, working to remove some of the branches protruding from the monomer strands, helping the polymer to pack more tightly, resulting in a more durable polymer. This polymer recipe held a very high amount of weight due to the compactness of the monomer strands, the previous recipe had 'give' to it but was less dense than it could have been, despite this, the polymer was able to hold high amounts of weight. This third recipe did not have as much 'give' to it, however it was very compact helping the polymer to be ale to hold more weight in general. It could be that making a polymer with high amounts of both plasticizer and acid would result in a very compact, but flexible poly which could hold more weight than any of the tests shown in this lab.
It is possible that a more precise measuring technique could have been used to perform these tests, to gain a more exact measurement of the amount of weight needed to break each polymer. However this would not seem to change the results in any way as the properties of each polymer (and the plasticizers and acid) where what were being tested, not the exact weight needed to break them.