Biodegradable plastic – The complete details

The Biodegradable word origin

The Bio word is taken from Greek bios ‘(course of) human life.’ The sense is extended in modern scientific usage to mean ‘organic life.’

What is the meaning of Biodegradable plastic?

Biobased materials indicate the substances obtained from living or dead animals or plants. Biobased materials are a large group of loosely related processing (or engineering) materials, which are mainly derived from substances originally existing in nature, such as in living tissues or organisms, but may also be obtained by synthetic methods.

Extraction of Biodegradable plastic from Biobased material:

Subsequently, biobased materials incorporate common commodities such as leather and wood and those that have undergone more extensive processing such as pectin, oleic acid, and carboxymethyl cellulose. In literature, the term “biobased material” is often used synonymously with biomass or biomaterial words.

The three words differ from each other slightly in definition and mostly in habitual uses. 

What is Biomass?

Biomass refers to animal or plant matter grown for benefits for the production of chemicals and fibers. Still, it does not include its products after processing. More commonly, biomass is frequently used in the literature of energy production, emphasizing its status in the carbon cycle as a renewable fuel.

The study of biodegradable plastic materials is now the large sector in material science and agrobusiness, as are

(a) the study of biomaterials in biomedical and pharmaceutical sciences and 

(b) the analysis of biomass in renewable energy.

Based on their sources and production, biobased materials can be divided into three major categories (1, 2):

Class 1 includes those removed (extraction, exuding, isolation after milling, etc.) from biomass. Examples are (a) polysaccharides such as starch and

cellulose and (b) proteins such as collagen and casein.

Class 2 includes polymers produced by a chemical

method using renewable biobased monomers. Examples are polyesters such as poly(lactic acid), which are made from the polymerization of lactic acid, a fermentation product of carbohydrate feedstock.

Category 2 biobased materials also include

monomers or low-molecular-weight chemicals (so-called “building blocks”) obtained from biobased feedstocks by chemical or biochemical methods, such as rosin, castor oil, and terpene.

Class 3 includes materials produced by microorganisms or genetically modified bacteria. Examples are bacterial cellulose and polyhydroxyalkanoates such as polyhydroxybutyrate.

Because of their overwhelming presence in the world and the versatility of their chemistry and architecture, biobased materials are the sources of many industrial products, such as medicinal, chemicals, fibers, paint, and plastics so on. 

Although most of them can be used for packaging purposes, the consumption of biobased materials in the packaging industry is only about 1%; many of these products are currently produced from petroleum-derived materials.

Comparison study of Biodegradable Plastic

Biobased materials are less dense than metal, and some petroleum-derived thermal plastics, are ideal components for many structural materials. 

Most biobased polymers perform in a fashion similar to that of conventional polymers. Unlike petroleum-derived materials, most biobased materials are biodegradable. This property enables the end-use products of biobased materials to be disposed of upon completing their useful life without causing any environmental concerns.

This is attractive in the production and applications of packaging materials and has become their primary focus. The use of biobased materials also addresses other economic issues:

the use of surplus stocks and the production of higher value-added material from agricultural products and byproducts. Therefore, the use of biobased materials promotes agrobusiness development.

Research for developing the Biodegradable plastic for packaging use:

Scientists and engineers are developing new technologies that will provide competitive cost for products from biobased materials, meet various applications’ standards, and optimize their performance.

Presently, important research areas include:

(I) Reproducibility and quality of biobased materials. It does not only depend on the methods and processing conditions of separation, purification, and fabrication, but also dramatically rely on the sources of raw materials, such as were grown, when harvested, and how and how long they are stored. All these variations make product quality control more complicated and difficult. 

(II) In composites, water absorption can be considered a disadvantage. Migration of water through the polymer can lead to disturbance of the filler/matrix interface, reducing the overall strength of the composites. Most biopolymers are hydrophilic. It is a challenge to improve the water-resistance of biobased materials to retain good mechanical properties when the composites are exposed to highly humid conditions.

(III) The durability of biobased materials is related to their biodegradability. The degradation of biobased products should be controllable, and their properties should be constant during the time of their useful life.

(IV) Gas barrier properties have specific significance in packaging materials. In particular, food packaging requires specific atmospheric conditions to sustain food freshness and overall quality during storage. Biobased materials mimic quite well the oxygen permeability of a wide range of the conventional petroleum-derived thermal plastics.

(V) Thermal stability – Most category one biobased material is not stable at higher temperatures, limiting applications and choices of processing methods.

(VI) Safety Biobased materials, particularly those that come from biological processes, may support microorganism growth. Concerns have arisen over the spread of novel trails in existing populations and the introduction of modified species.

 

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