A Group of IPB Researchers Invented Thermoplastics from Palm Oil
Plastic POLYmers are made from building block MONOmers. The naturally occurring monomers (feedstocks ) can be derived from plants, coal, natural gas or oil. Conventional plastic raw materials derived from petroleum or natural gas have a limited supply, as it is a non-renewable resource. Base chemicals, such as ethylene, are of high importance to our society, e.g. in plastic. However, the fossil feedstocks that these chemicals are currently based upon are of limited availability, and have a considerable environmental impact. The use of conventional plastics as packaging materials causes various problems. Its low ability to degrade naturally leads to environmental pollution. Eventually, oil-based polymer materials have to be replaced in many applications by sustainable, inexpensive, natural materials from renewable resources. This encourages the development of the use of biodegradable plastics, one of which is thermoplastic starch as an environmentally friendly alternative packaging.
Sabrina Manora Indriyani and Farah Fahma of the Department of Agricultural Industrial Technology of the Faculty of Agricultural Technology of Bogor Agricultural University (FATETA IPB) implemented research program on the application of nanofiber of tandan kosong kelapa sawit (TKKS empty palm oil bunches) as reinforcement agent for thermoplastic starch-polyvinyl alcohol composite (TPS-PVA).
Farah said that thermoplastics are plastics that are softened repeatedly by using heat and will harden when cold. A thermoplastic, or thermosoftening plastic, is a plastic material, a polymer, that becomes pliable or moldable above a specific temperature and solidifies upon cooling. Starch is not exactly thermoplastic, but the presence of plasticizer, heating and mechanical process will break the semicrystalline structure. These conditions allow the starch to be processed into thermoplastics.
Crops that are high in starch are the principal source of food calories for people globally, although many affluent people tend to think of starch as a thickener for sauces and gravies or as “bad carbs” in a health conscious diet. On the other hand, even technologically savvy people might not mention starch as a potential raw material for making environmentally friendly plastics. "Starch is a thermoplastic raw material that can be degraded naturally so it is safe for the environment. The addition of cellulose nanofibers until 3% wt increased tensile strength and crystallinity of the composite films. Composite materials generally consist of two or more different materials, namely a filler or reinforcement (reinforcement) and a binder called a matrix. The reinforcement of nanofibers was investigated from the improvements in mechanical properties based on tensile tests, dynamic mechanical analysis, and differential scanning calorimetry," she said.
She also added, cellulose is a fiber that is abundant in nature, strong and can be degraded naturally. Cellulose fibers are fibers made with ether or esters of cellulose, which can be obtained from the bark, wood or leaves of plants, or from a plant-based material. Cellulose can be obtained from various sources of natural fiber, one of which is TKKS which is a waste from the palm oil industry. "TKKS is known containing cellulose acetates having an acetyl content of at least 44.4%, so TKKS has the potential to be utilized as reinforcement agent on thermoplastic starch composite as well as increase TKKS added value," she said.
The research revealed that stability of cellulose nanofibers suspension not only reflects its ability to be well distributed in the matrix of the film, but also related to the crystallinity of cellulose nanofibers, further affect the mechanical properties of the film, improving the effectiveness cellulose nanofibers as a water vapour transmission barrier, and to support the transparency properties of the film. Cellulose nanofibers with higher crystallinity not only support the increased the strength of the film, but it can increase the effectiveness of the film as a water vapour transmission barrier, as well as inhibit the reduction of film transparency due to the use of fillers. The addition of glycerol improves elongation, light transmission and moisture transmission rate in the film, but decreases the tensile strength of the film. (Wied)
