Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Make your likes visible on Facebook?

Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.

No, thanks

The Properties and Parameters of Experimental Bioplastics

No description
by

gabriella smith

on 13 February 2014

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of The Properties and Parameters of Experimental Bioplastics

The Properties and Parameters of Experimental Bioplastics
Polymers

are a long chain of molecules formed from monomers in a chemical reaction.
Primary
forces hold the monomers together whilst
secondary
forces hold the polymer chains together. These secondary bonds are heat dependent, and will break with energy input.
Unlike elements with defined temperature points (freezing, melting etc) plastics have a

fluid transition range
.
Plastics disintegrate (burn) before becoming gaseous.

Bio-based Thermoplastics
Biopolymers
are created from a range of different raw materials, the main renewable sources of biopolymers are proteins, polysaccharides and lipids.

Proteins
are polymers of amino acids.
Lipids
are polymers made of fatty acids and glycerol.
Polysaccharides
are made from chains of charbohydrates (monosaccharides) Starch, glycogen and cellulose are all polysaccarides made up of glucose.
A way of processing protein-based biomaterials is the mechanical method, which consists of mixing proteins and plasticizer to obtain a dough-like material



The testing procedures to categorize plastics are intense and expensive. This is one of the reasons innovative products do not appear in the wider market. There are hundreds of tests controlled by bodies such as,
ASTM

International
which can be us to define the properties and therefore the identity of the new material. To understand the properties of basic commercial bioplastics I interpreted some of the ASTM's tests, trying to cover a wide range of properties.


Hybrid Plastics
Or Blended bio polymers

Plastics
Plastics
- Materials with long molecular chains (monomers) of natural or fossil raw materials, produced by chemical or biochemical reactions

4 types of plastic
: elastomers, thermosets, thermoplastics and thermoplastic elastomers.
Thermoplastics plastics
which soften or melt when heated and harden when cooled. They have an uncross-linked structure.
Wide range of properties
and source materials, can be blended or additives can be used.
Lack of interest in innovation
All of the most popular commercial plastics were invented before 1940.
The Morphology of Macromolecules
Creating Bioplastics
Proteins

can come from many sources animal, bacteria, and plant. Many proteins are inexpensive, wasted, and abundant raw materials. Animal protein can be found in gelatine, a product usually made from pig and bovine skin and bones - waste products from animal farming. Plant protein can be derived from waste too, certain seeds, stalks etc contain more protein than the equivalent weight of animal material
.
Polysaccharides
,
such as starch and

monosaccharides
such as glycerol can also be used. Polysaccarides and monoscaccarides can be derived from bacteria, plants and animals so again, there is a lot of potential for

sustainable raw materials
.
Thermoplastics
-
heat deformable

Amorphous
or
semi crystalline
.


Semi-crystalline plastics are harder and more heat resistant (although do expand more when heated). Their chains have some structured crystalline regions
Amorphous plastics can be dissolved and their chains are random.
BioPolymer(s)
+
Water
+
Heat
+
Mixing
=
BioPlastic
The plastics are poured into a mold
and left to dry. Different
BioPolymer

bases
create plastics with different properties. This is because of how the molecular chains are organized, (un)crossed, and their length.
Water absorption, thermo-insulation, tensile strength and flexibility tests for
Thermoplastic Starch
,
Glycerin based
and
Vegetable Oil
based plastics
Plastic Properties
Results 1.0
Gelatine based polymers absorbed the most water, was the best insulator and had the greatest tensile strength. These properties make sense considering its molecular structure: uncross-linked chains which are semi-crystalline.
manufacturing methods
Chemical Structure of plastics
In The Laboratory
Production of Plastic Components
The most important manufacturing methods for plastics are injection molding, extrusion, calendering (rolling), compression molding, foaming and casting.
Working methods such as thermal reforming, sawing and milling are also common post production.
casting experiments:

Layered blended plastics using injection, compression casting, foamed unset plastic
.
For in-materio ballistic analogue... one can not change the laws of physics, so one changes the structure and dynamics of the substrate S. Stepney
Further Investigation
How does temperature change effect the physical properties of thermoplastic biopolymers?
Experiment List:
0. How does the plastic react to high temperatures?
1. What happens if the plastic is heated and re-set at various temperatures?
2. How does plastic change if set at different temperatures?
3. How does the plastic change if frozen and left to thaw at different temperatures?
Melting and freezing can be reversible processes
Heating and cooling are reversible processes
Extreme temperature swings cause scarring to the plastic
Setting in a cool environment produces unblemished plastics
The gelatine based bio polymer can be re-set after melting but has a very low glass transition temperature

Blended Biopolymer 1
vegetable oil and gelatine based polymer
protein and polysaccharides
High Glass transition temp (80-90)
Strong yet flexible sheet casting.
High water absorption.
High tensile strength.

Blended biopolymer 2
vegetable oil, starch and glycerine based bio polymer
protein and polysaccharides
(inc starch)
rigid form, yet flexible.
Absorbs less water
High Compressive strength

preparing the specimens for testing, experiment 0, experiment 1 [gly], experiment 2. [oil], experiment 3. [gel]
Experiment Results
Production Parameters
There are certain difficulties associated with creating bio-plastics in my "Kitchen Laboratory":


Contamination
Bioplastics are unfortunately prone to contamination with mold or bacteria. It is imperative that every item used in making the plastic is absolutely clean, that the raw materials have been kept clean and dry and glycerine solutions etc. can not be kept for long periods of time.

Casting process
I personally have very little space to store sheets of bio plastics. Sheets of plastics are preferable for me as they take up less space, dry quicker and I can cast them in wipe clean baking trays to minimize contamination.
Contaminated Plastic
(left)

Contamination can also occur if layers of wet plastics are left to dry out together. The plastics need water to evaporate in order to set, if moisture becomes trapped in the casting process then contamination will occur.

If contamination takes place the damage is irreversible and the plastic will begin to break down immediately. The plastic may totally disintegrate in just a few days.

The larger the sheet of plastic, the longer the plastic takes to dry and the greater risk of contamination.

Ideally, laboratory conditions would be used to create the plastics or at least a chilled, clean environment.
Casting Process

(right) Plastics setting in the 'Laboratory'

Before casting into wipe-clean trays I used card formers and plastic trays - these were particularly prone to contamination.

The setting process can take up to 1-2 weeks depending on the formula and size of the plastic sheet.

Ideally the plastics would be set over a long period around 8 degrees centigrade.

Due to lack of storage and the size of wipe-clean baking trays; the majority of sheets I have been creating are 300x300x5mm.


Full transcript