Inedible Woody Bio-based Plastic Material Technology

In order to increase the variety of eco-conscious bioplastic materials, Fuji Xerox is researching and developing a new type of cellulose-based bioplastic in addition to polylactic acid (PLA).

Cellulose is an organic compound found in wood. Compared to other materials, which are found only in certain countries, wood materials are available worldwide and require less transport, thereby reducing CO2 emissions. In addition, using an inedible substance like cellulose avoids the indirect use of farmlandNote1 and consequently does not compete with food supplies.

However, cellulose is generally less durable and flame resistant, and thus is more problematic to handle than PLA.

Fuji Xerox has developed an original alloy compatibilization technology to give cellulose a strength equivalent to that of conventional petroleum-based resins.
First, the strong hydrogen bond of the cellulose is loosened with chemical reactions to facilitate the blending of petroleum-based plastic with cellulose molecules. Then, the type of petroleum-based plastic is selected and the amount of its molecules is adjusted, so as to reduce the difference in melt viscosity when blended with cellulose. As a result, the dispersion of cellulose and petroleum-based plastic is optimized, and compatibility is improved without the use of additives known as compatibilizing agents.

As you can see in Fig. 1, cellulose and petroleum-based plastic are normally difficult to mix. Looking at the texture of the new biomass plastic under a microscope, however, we can see that the cellulose and petroleum-based plastic are well mixed (Fig. 2). This high compatibility results in a plastic with the strength to resist impact and flames.

The inedible woody biomass plastic developed by Fuji Xerox offers a weld strengthNote2 and flexibility that surpass those of petroleum-based plastics, even though it is cellulose-based and consists of approximately 40 percent plant-based materials by weight. It is also as equally flame resistant as petroleum-based plastics. This biomass plastic has obtained the "BiomassPla" logo from the Japan BioPlastics Association.

Fig. 1: Before introducing compatibilization technology

Fig. 1: Before introducing compatibilization technology

In Fig. 1, the petroleum-based plastic (polycarbonate) demonstrates a spindle-like structure (sticking out like the tip of a rope) and is surrounded by cellulose. Both substances are very unevenly dispersed, with separations between the adhered surfaces. This material has low mechanical strength, readily absorbs water, and undergoes significant dimensional change.

Fig. 2: After introducing compatibilization technology

Fig. 2: After introducing compatibilization technology

The grainy features are composed of the petroleum-based plastic. The other areas are composed of cellulose. The image indicates satisfactory dispersion that results in high mechanical strength, low water absorption, and reduced dimensional change.

Note 1
The indirect use of farmland refers to the planting of biomass materials in fields used to produce food.
Note 2
An important property for injection molding materials that is required at the contact point of plastic resin when injected into a mold from two sides.