Blends lignin-based thermoplastics

Figure 5. Tensile behaviour to point of ftacture for 85% kraft lignin-based thermoplastic blends with poly(vinyl acetate) in presence of diethyleneglycol dibenzoate (1.6%) and indene (0.8%). Stress-strain a-e curves determined for material test pieces at strain rate of 4.5 x 10" sec" graphical data from reference 1.

Be that as it may, some important insight at the molecular level into the constitution of the 85% kraft lignin-based thermoplastics was furnished by a small modification to the formulation that had been developed for these blends. As already mentioned (see section 2.1), kraft lignin preparations are... 

Li, Y., and Sarkanen, S., 2001, Kraft lignin-based thermoplastic polymer blends. In 11th International Symposium on Wood and Pulping Chemistry ATIP, Paris, Vol. I, pp. 75-78. 

The utilization of TPS for the production of biodegradable plastics has increased and has been the object of several studies in the last decade. However, TPS has two main drawbacks namely its water affinity and its poor mechanical properties. To overcome these problems, the addition of other materials to TPS is necessary. In order to increase its water resistance, TPS has been blended with synthetic polymers and modified by cross-linking agents such as Ca and Zr salts. Substances such as waxes and lignin have also been tested to decrease the water uptake of starch-based materials. TPS s mechanical properties have usually been improved by addition of synthetic polymers, such as ethylene-acryhc acid and ethylene-vinyl alcohol copolymers. Another approach requires the use of natural fibers and mineral fillers. The inclusion of reinforcing fillers such as fibers could, however, enhance the degradation of thermoplastic starch because of the increase in the melt viscosity [79-81]. 

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