Another major reason for this renewed growth is an increased awareness for environment, reflected in phrases such as protection of resources, reduction of CO₂ emission and recycling. Other further advantages/disadvantages of natural fibers versus their counter parts can be seen in figure 1.

In order to be molded natural fibers are used in mixture with thermoset or thermoplastic polymers.

• Thermoset polymers such as PF (phenolic resin) or (EP) epoxy are binders for cotton or similar fibers for applications such as inner trim parts or damping materials. Some of their advantages are: sufficient mechanical properties (stiffness and strength), comparable with the glass composite, have a superior thermal stability, lower water absorption compared with thermoplastic polymers (PP) and acceptably low prices levels. Their disadvantages are related to the moisture and air: moisture can affect the chemical reaction therefore the fibers have to be dried before down to 2-3 percent; the air present in the fibers leads to many voids in matrix thus a poor fiber matrix interface. Another downside of PF refers to ecological problems: the thermal disposal needs high temperature as an incomplete combustion occurs at lower temperatures.