Many people have been asking about how we plan on developing our composite bamboo products. Conventional polymers are petroleum based and are harmful to the environment. These polymers do not biodegrade after there intended use is complete, and recycling polymers has been a challenge.
This begs the question: How are we going to make composites with green sustainable materials?
What is a Biopolymer?
Ok, before we get to technical in this article, we would like to give you some more plain language to offer context. Composites exist in nature and are everywhere. Wood is a composite. It is is made up of a cellulose polymer and a special ingredient call Lignin, to hold it all together. When we discuss composites for bamboo, it is reforming the natural composite that is bamboo, for the shape of our choice. We do this to make refined finish wood for building. There are many things we can do once we have made composite bamboo, but the point is to do it naturally. This discussion is about our analysis of which Biopolymer we have chosen to use at M.A.E. Make sense? Ok, let’s get a bit nerdy now:
Viable Biopolymers for use with Bamboo:
Our mission at M.A.E. is to produce green building materials that are 100% natural. The process of making them is non-polluting; the raw materials are regenerative and sustainable. This makes the conversation a bit more simple. This graph below will represent all types of polymers that exist. For the sake of our discussion, the BioPolymer MUST adhere to 2 rules: The materials are Fully Bio-based and Fully Biodegradable. Check out this graph which comes from an excellent PDF read on the subject:
With this graph, we can quickly derive that only 4 polymers fit the M.A.E. criteria: TPS, PLA, PHA, and Cellulose Acetate
TPS – ThermoPlastic Starch
Starch and chitosan are abundant. They occur naturally as types of polysaccharide. Both of them are cheap, renewable, non-toxic, and biodegradable. The starch/chitosan blend exhibits good film forming property, so this bioplastic is commonly used in packaging. Regeneration occurs from carbon dioxide and water by the process photosynthesis in plants. Due to its complete biodegradability, low cost, and regenerative nature, starch is considered as a promising candidate for developing sustainable materials. In light of this, if you dig deeper you’ll find that starch has been receiving growing attention for over 45 years. Many people have developed starch-based polymers to reduce the dependence on fossil fuels. Benefits also include reducing environmental impact of conventional polymers.
PLA – Poly-L-actic Acid
Poly-L-lactic acid is truly promising. It is widely available and has a fairly hot melting point of 160°C; allowing processing conditions similar to those used in conventional polymers. PLA also has connectivity inclusion. Testing shows that with 65% bamboo fibre in PLA the force at the breaking point is 3x higher. PLA in particular has fantastic effects when used as a structural building composite because it can be hardened to a heavy weight and does not mix well with water, yet breathable in certain applications. The traits of PLA give the Biopolymer a long lifetime to maintain its solid form without rapid degradation. However, it can be industrially biodegraded when proper composting techniques are used.
PHA – Polyhydroxyalkanoates – OR just PHA’s
It is a mouthful to say for us as well, but as Wikipedia explains:
PHAs are linear polyesters produced in nature by bacterialfermentation of sugar or lipids. They are produced by the bacteria to store carbon and energy. More than 150 different monomers can be combined within this family to give materials with extremely different properties. These plastics are biodegradeable and are used in the production of bioplastics.
Mechanical properties and biocompatibility of PHA can also be changed by blending, modifying the surface or combining PHA with other polymers, enzymes and inorganic materials, making it possible for a wider range of applications.
In other words, these are Biopolymers derived from Algae and other similar water based biomass. The success of proliferating PHA’s is in the rapid reproduction rate of the algae cells over a short period of time. Then growth becomes exponential.
Cellulose as a Biopolymer has the longest history dating back to the 18th century. Generally used in application such as photography film, it largely is harvested from cotton and converted into Cellulose Acetate. Currently, the most rigid form for cellulose is for eyeglass frames, but perhaps future advancements will show greater possibilities for it to be used as a building material.
Our Preferred Choice is: PLA
When accounting for all the variables included in combining these Biopolymers with Bamboo, one clear winner emerges. The wide availability and dense hardening nature of PLAs make them the preferred choice for our composite bamboo products. In Central America, the most abundant source for PLAs comes from Sugar Cane. The oil extraction process creates the PLAs which are then combined into a resin mixture filled and reinforced by Bamboo. This is lightly pressed into forms and heated till cured and air dried.
We are very excited to create more efficiency in the compositing process, so subscribe to our newsletter below to receive updates on our progress.